RetainCountChecker.cpp revision 15d18e15384c9e992bd294fc56f4fdf770763d71
1//==-- RetainCountChecker.cpp - Checks for leaks and other issues -*- C++ -*--// 2// 3// The LLVM Compiler Infrastructure 4// 5// This file is distributed under the University of Illinois Open Source 6// License. See LICENSE.TXT for details. 7// 8//===----------------------------------------------------------------------===// 9// 10// This file defines the methods for RetainCountChecker, which implements 11// a reference count checker for Core Foundation and Cocoa on (Mac OS X). 12// 13//===----------------------------------------------------------------------===// 14 15#include "ClangSACheckers.h" 16#include "clang/AST/DeclObjC.h" 17#include "clang/AST/DeclCXX.h" 18#include "clang/Basic/LangOptions.h" 19#include "clang/Basic/SourceManager.h" 20#include "clang/Analysis/DomainSpecific/CocoaConventions.h" 21#include "clang/AST/ParentMap.h" 22#include "clang/StaticAnalyzer/Core/Checker.h" 23#include "clang/StaticAnalyzer/Core/CheckerManager.h" 24#include "clang/StaticAnalyzer/Core/BugReporter/BugType.h" 25#include "clang/StaticAnalyzer/Core/BugReporter/PathDiagnostic.h" 26#include "clang/StaticAnalyzer/Core/PathSensitive/CallEvent.h" 27#include "clang/StaticAnalyzer/Core/PathSensitive/CheckerContext.h" 28#include "clang/StaticAnalyzer/Core/PathSensitive/ProgramStateTrait.h" 29#include "clang/StaticAnalyzer/Core/PathSensitive/SymbolManager.h" 30#include "llvm/ADT/DenseMap.h" 31#include "llvm/ADT/FoldingSet.h" 32#include "llvm/ADT/ImmutableList.h" 33#include "llvm/ADT/ImmutableMap.h" 34#include "llvm/ADT/SmallString.h" 35#include "llvm/ADT/STLExtras.h" 36#include "llvm/ADT/StringExtras.h" 37#include <cstdarg> 38 39using namespace clang; 40using namespace ento; 41using llvm::StrInStrNoCase; 42 43namespace { 44/// Wrapper around different kinds of node builder, so that helper functions 45/// can have a common interface. 46class GenericNodeBuilderRefCount { 47 CheckerContext *C; 48 const ProgramPointTag *tag; 49public: 50 GenericNodeBuilderRefCount(CheckerContext &c, 51 const ProgramPointTag *t = 0) 52 : C(&c), tag(t){} 53 54 ExplodedNode *MakeNode(ProgramStateRef state, ExplodedNode *Pred, 55 bool MarkAsSink = false) { 56 return C->addTransition(state, Pred, tag, MarkAsSink); 57 } 58}; 59} // end anonymous namespace 60 61//===----------------------------------------------------------------------===// 62// Primitives used for constructing summaries for function/method calls. 63//===----------------------------------------------------------------------===// 64 65/// ArgEffect is used to summarize a function/method call's effect on a 66/// particular argument. 67enum ArgEffect { DoNothing, Autorelease, Dealloc, DecRef, DecRefMsg, 68 DecRefBridgedTransfered, 69 DecRefAndStopTracking, DecRefMsgAndStopTracking, 70 IncRefMsg, IncRef, MakeCollectable, MayEscape, 71 NewAutoreleasePool, StopTracking }; 72 73namespace llvm { 74template <> struct FoldingSetTrait<ArgEffect> { 75static inline void Profile(const ArgEffect X, FoldingSetNodeID& ID) { 76 ID.AddInteger((unsigned) X); 77} 78}; 79} // end llvm namespace 80 81/// ArgEffects summarizes the effects of a function/method call on all of 82/// its arguments. 83typedef llvm::ImmutableMap<unsigned,ArgEffect> ArgEffects; 84 85namespace { 86 87/// RetEffect is used to summarize a function/method call's behavior with 88/// respect to its return value. 89class RetEffect { 90public: 91 enum Kind { NoRet, OwnedSymbol, OwnedAllocatedSymbol, 92 NotOwnedSymbol, GCNotOwnedSymbol, ARCNotOwnedSymbol, 93 OwnedWhenTrackedReceiver }; 94 95 enum ObjKind { CF, ObjC, AnyObj }; 96 97private: 98 Kind K; 99 ObjKind O; 100 101 RetEffect(Kind k, ObjKind o = AnyObj) : K(k), O(o) {} 102 103public: 104 Kind getKind() const { return K; } 105 106 ObjKind getObjKind() const { return O; } 107 108 bool isOwned() const { 109 return K == OwnedSymbol || K == OwnedAllocatedSymbol || 110 K == OwnedWhenTrackedReceiver; 111 } 112 113 bool operator==(const RetEffect &Other) const { 114 return K == Other.K && O == Other.O; 115 } 116 117 static RetEffect MakeOwnedWhenTrackedReceiver() { 118 return RetEffect(OwnedWhenTrackedReceiver, ObjC); 119 } 120 121 static RetEffect MakeOwned(ObjKind o, bool isAllocated = false) { 122 return RetEffect(isAllocated ? OwnedAllocatedSymbol : OwnedSymbol, o); 123 } 124 static RetEffect MakeNotOwned(ObjKind o) { 125 return RetEffect(NotOwnedSymbol, o); 126 } 127 static RetEffect MakeGCNotOwned() { 128 return RetEffect(GCNotOwnedSymbol, ObjC); 129 } 130 static RetEffect MakeARCNotOwned() { 131 return RetEffect(ARCNotOwnedSymbol, ObjC); 132 } 133 static RetEffect MakeNoRet() { 134 return RetEffect(NoRet); 135 } 136 137 void Profile(llvm::FoldingSetNodeID& ID) const { 138 ID.AddInteger((unsigned) K); 139 ID.AddInteger((unsigned) O); 140 } 141}; 142 143//===----------------------------------------------------------------------===// 144// Reference-counting logic (typestate + counts). 145//===----------------------------------------------------------------------===// 146 147class RefVal { 148public: 149 enum Kind { 150 Owned = 0, // Owning reference. 151 NotOwned, // Reference is not owned by still valid (not freed). 152 Released, // Object has been released. 153 ReturnedOwned, // Returned object passes ownership to caller. 154 ReturnedNotOwned, // Return object does not pass ownership to caller. 155 ERROR_START, 156 ErrorDeallocNotOwned, // -dealloc called on non-owned object. 157 ErrorDeallocGC, // Calling -dealloc with GC enabled. 158 ErrorUseAfterRelease, // Object used after released. 159 ErrorReleaseNotOwned, // Release of an object that was not owned. 160 ERROR_LEAK_START, 161 ErrorLeak, // A memory leak due to excessive reference counts. 162 ErrorLeakReturned, // A memory leak due to the returning method not having 163 // the correct naming conventions. 164 ErrorGCLeakReturned, 165 ErrorOverAutorelease, 166 ErrorReturnedNotOwned 167 }; 168 169private: 170 Kind kind; 171 RetEffect::ObjKind okind; 172 unsigned Cnt; 173 unsigned ACnt; 174 QualType T; 175 176 RefVal(Kind k, RetEffect::ObjKind o, unsigned cnt, unsigned acnt, QualType t) 177 : kind(k), okind(o), Cnt(cnt), ACnt(acnt), T(t) {} 178 179public: 180 Kind getKind() const { return kind; } 181 182 RetEffect::ObjKind getObjKind() const { return okind; } 183 184 unsigned getCount() const { return Cnt; } 185 unsigned getAutoreleaseCount() const { return ACnt; } 186 unsigned getCombinedCounts() const { return Cnt + ACnt; } 187 void clearCounts() { Cnt = 0; ACnt = 0; } 188 void setCount(unsigned i) { Cnt = i; } 189 void setAutoreleaseCount(unsigned i) { ACnt = i; } 190 191 QualType getType() const { return T; } 192 193 bool isOwned() const { 194 return getKind() == Owned; 195 } 196 197 bool isNotOwned() const { 198 return getKind() == NotOwned; 199 } 200 201 bool isReturnedOwned() const { 202 return getKind() == ReturnedOwned; 203 } 204 205 bool isReturnedNotOwned() const { 206 return getKind() == ReturnedNotOwned; 207 } 208 209 static RefVal makeOwned(RetEffect::ObjKind o, QualType t, 210 unsigned Count = 1) { 211 return RefVal(Owned, o, Count, 0, t); 212 } 213 214 static RefVal makeNotOwned(RetEffect::ObjKind o, QualType t, 215 unsigned Count = 0) { 216 return RefVal(NotOwned, o, Count, 0, t); 217 } 218 219 // Comparison, profiling, and pretty-printing. 220 221 bool operator==(const RefVal& X) const { 222 return kind == X.kind && Cnt == X.Cnt && T == X.T && ACnt == X.ACnt; 223 } 224 225 RefVal operator-(size_t i) const { 226 return RefVal(getKind(), getObjKind(), getCount() - i, 227 getAutoreleaseCount(), getType()); 228 } 229 230 RefVal operator+(size_t i) const { 231 return RefVal(getKind(), getObjKind(), getCount() + i, 232 getAutoreleaseCount(), getType()); 233 } 234 235 RefVal operator^(Kind k) const { 236 return RefVal(k, getObjKind(), getCount(), getAutoreleaseCount(), 237 getType()); 238 } 239 240 RefVal autorelease() const { 241 return RefVal(getKind(), getObjKind(), getCount(), getAutoreleaseCount()+1, 242 getType()); 243 } 244 245 void Profile(llvm::FoldingSetNodeID& ID) const { 246 ID.AddInteger((unsigned) kind); 247 ID.AddInteger(Cnt); 248 ID.AddInteger(ACnt); 249 ID.Add(T); 250 } 251 252 void print(raw_ostream &Out) const; 253}; 254 255void RefVal::print(raw_ostream &Out) const { 256 if (!T.isNull()) 257 Out << "Tracked " << T.getAsString() << '/'; 258 259 switch (getKind()) { 260 default: llvm_unreachable("Invalid RefVal kind"); 261 case Owned: { 262 Out << "Owned"; 263 unsigned cnt = getCount(); 264 if (cnt) Out << " (+ " << cnt << ")"; 265 break; 266 } 267 268 case NotOwned: { 269 Out << "NotOwned"; 270 unsigned cnt = getCount(); 271 if (cnt) Out << " (+ " << cnt << ")"; 272 break; 273 } 274 275 case ReturnedOwned: { 276 Out << "ReturnedOwned"; 277 unsigned cnt = getCount(); 278 if (cnt) Out << " (+ " << cnt << ")"; 279 break; 280 } 281 282 case ReturnedNotOwned: { 283 Out << "ReturnedNotOwned"; 284 unsigned cnt = getCount(); 285 if (cnt) Out << " (+ " << cnt << ")"; 286 break; 287 } 288 289 case Released: 290 Out << "Released"; 291 break; 292 293 case ErrorDeallocGC: 294 Out << "-dealloc (GC)"; 295 break; 296 297 case ErrorDeallocNotOwned: 298 Out << "-dealloc (not-owned)"; 299 break; 300 301 case ErrorLeak: 302 Out << "Leaked"; 303 break; 304 305 case ErrorLeakReturned: 306 Out << "Leaked (Bad naming)"; 307 break; 308 309 case ErrorGCLeakReturned: 310 Out << "Leaked (GC-ed at return)"; 311 break; 312 313 case ErrorUseAfterRelease: 314 Out << "Use-After-Release [ERROR]"; 315 break; 316 317 case ErrorReleaseNotOwned: 318 Out << "Release of Not-Owned [ERROR]"; 319 break; 320 321 case RefVal::ErrorOverAutorelease: 322 Out << "Over autoreleased"; 323 break; 324 325 case RefVal::ErrorReturnedNotOwned: 326 Out << "Non-owned object returned instead of owned"; 327 break; 328 } 329 330 if (ACnt) { 331 Out << " [ARC +" << ACnt << ']'; 332 } 333} 334} //end anonymous namespace 335 336//===----------------------------------------------------------------------===// 337// RefBindings - State used to track object reference counts. 338//===----------------------------------------------------------------------===// 339 340typedef llvm::ImmutableMap<SymbolRef, RefVal> RefBindings; 341 342namespace clang { 343namespace ento { 344template<> 345struct ProgramStateTrait<RefBindings> 346 : public ProgramStatePartialTrait<RefBindings> { 347 static void *GDMIndex() { 348 static int RefBIndex = 0; 349 return &RefBIndex; 350 } 351}; 352} 353} 354 355//===----------------------------------------------------------------------===// 356// Function/Method behavior summaries. 357//===----------------------------------------------------------------------===// 358 359namespace { 360class RetainSummary { 361 /// Args - a map of (index, ArgEffect) pairs, where index 362 /// specifies the argument (starting from 0). This can be sparsely 363 /// populated; arguments with no entry in Args use 'DefaultArgEffect'. 364 ArgEffects Args; 365 366 /// DefaultArgEffect - The default ArgEffect to apply to arguments that 367 /// do not have an entry in Args. 368 ArgEffect DefaultArgEffect; 369 370 /// Receiver - If this summary applies to an Objective-C message expression, 371 /// this is the effect applied to the state of the receiver. 372 ArgEffect Receiver; 373 374 /// Ret - The effect on the return value. Used to indicate if the 375 /// function/method call returns a new tracked symbol. 376 RetEffect Ret; 377 378public: 379 RetainSummary(ArgEffects A, RetEffect R, ArgEffect defaultEff, 380 ArgEffect ReceiverEff) 381 : Args(A), DefaultArgEffect(defaultEff), Receiver(ReceiverEff), Ret(R) {} 382 383 /// getArg - Return the argument effect on the argument specified by 384 /// idx (starting from 0). 385 ArgEffect getArg(unsigned idx) const { 386 if (const ArgEffect *AE = Args.lookup(idx)) 387 return *AE; 388 389 return DefaultArgEffect; 390 } 391 392 void addArg(ArgEffects::Factory &af, unsigned idx, ArgEffect e) { 393 Args = af.add(Args, idx, e); 394 } 395 396 /// setDefaultArgEffect - Set the default argument effect. 397 void setDefaultArgEffect(ArgEffect E) { 398 DefaultArgEffect = E; 399 } 400 401 /// getRetEffect - Returns the effect on the return value of the call. 402 RetEffect getRetEffect() const { return Ret; } 403 404 /// setRetEffect - Set the effect of the return value of the call. 405 void setRetEffect(RetEffect E) { Ret = E; } 406 407 408 /// Sets the effect on the receiver of the message. 409 void setReceiverEffect(ArgEffect e) { Receiver = e; } 410 411 /// getReceiverEffect - Returns the effect on the receiver of the call. 412 /// This is only meaningful if the summary applies to an ObjCMessageExpr*. 413 ArgEffect getReceiverEffect() const { return Receiver; } 414 415 /// Test if two retain summaries are identical. Note that merely equivalent 416 /// summaries are not necessarily identical (for example, if an explicit 417 /// argument effect matches the default effect). 418 bool operator==(const RetainSummary &Other) const { 419 return Args == Other.Args && DefaultArgEffect == Other.DefaultArgEffect && 420 Receiver == Other.Receiver && Ret == Other.Ret; 421 } 422 423 /// Profile this summary for inclusion in a FoldingSet. 424 void Profile(llvm::FoldingSetNodeID& ID) const { 425 ID.Add(Args); 426 ID.Add(DefaultArgEffect); 427 ID.Add(Receiver); 428 ID.Add(Ret); 429 } 430 431 /// A retain summary is simple if it has no ArgEffects other than the default. 432 bool isSimple() const { 433 return Args.isEmpty(); 434 } 435 436private: 437 ArgEffects getArgEffects() const { return Args; } 438 ArgEffect getDefaultArgEffect() const { return DefaultArgEffect; } 439 440 friend class RetainSummaryManager; 441}; 442} // end anonymous namespace 443 444//===----------------------------------------------------------------------===// 445// Data structures for constructing summaries. 446//===----------------------------------------------------------------------===// 447 448namespace { 449class ObjCSummaryKey { 450 IdentifierInfo* II; 451 Selector S; 452public: 453 ObjCSummaryKey(IdentifierInfo* ii, Selector s) 454 : II(ii), S(s) {} 455 456 ObjCSummaryKey(const ObjCInterfaceDecl *d, Selector s) 457 : II(d ? d->getIdentifier() : 0), S(s) {} 458 459 ObjCSummaryKey(Selector s) 460 : II(0), S(s) {} 461 462 IdentifierInfo *getIdentifier() const { return II; } 463 Selector getSelector() const { return S; } 464}; 465} 466 467namespace llvm { 468template <> struct DenseMapInfo<ObjCSummaryKey> { 469 static inline ObjCSummaryKey getEmptyKey() { 470 return ObjCSummaryKey(DenseMapInfo<IdentifierInfo*>::getEmptyKey(), 471 DenseMapInfo<Selector>::getEmptyKey()); 472 } 473 474 static inline ObjCSummaryKey getTombstoneKey() { 475 return ObjCSummaryKey(DenseMapInfo<IdentifierInfo*>::getTombstoneKey(), 476 DenseMapInfo<Selector>::getTombstoneKey()); 477 } 478 479 static unsigned getHashValue(const ObjCSummaryKey &V) { 480 typedef std::pair<IdentifierInfo*, Selector> PairTy; 481 return DenseMapInfo<PairTy>::getHashValue(PairTy(V.getIdentifier(), 482 V.getSelector())); 483 } 484 485 static bool isEqual(const ObjCSummaryKey& LHS, const ObjCSummaryKey& RHS) { 486 return LHS.getIdentifier() == RHS.getIdentifier() && 487 LHS.getSelector() == RHS.getSelector(); 488 } 489 490}; 491template <> 492struct isPodLike<ObjCSummaryKey> { static const bool value = true; }; 493} // end llvm namespace 494 495namespace { 496class ObjCSummaryCache { 497 typedef llvm::DenseMap<ObjCSummaryKey, const RetainSummary *> MapTy; 498 MapTy M; 499public: 500 ObjCSummaryCache() {} 501 502 const RetainSummary * find(const ObjCInterfaceDecl *D, Selector S) { 503 // Do a lookup with the (D,S) pair. If we find a match return 504 // the iterator. 505 ObjCSummaryKey K(D, S); 506 MapTy::iterator I = M.find(K); 507 508 if (I != M.end()) 509 return I->second; 510 if (!D) 511 return NULL; 512 513 // Walk the super chain. If we find a hit with a parent, we'll end 514 // up returning that summary. We actually allow that key (null,S), as 515 // we cache summaries for the null ObjCInterfaceDecl* to allow us to 516 // generate initial summaries without having to worry about NSObject 517 // being declared. 518 // FIXME: We may change this at some point. 519 for (ObjCInterfaceDecl *C=D->getSuperClass() ;; C=C->getSuperClass()) { 520 if ((I = M.find(ObjCSummaryKey(C, S))) != M.end()) 521 break; 522 523 if (!C) 524 return NULL; 525 } 526 527 // Cache the summary with original key to make the next lookup faster 528 // and return the iterator. 529 const RetainSummary *Summ = I->second; 530 M[K] = Summ; 531 return Summ; 532 } 533 534 const RetainSummary *find(IdentifierInfo* II, Selector S) { 535 // FIXME: Class method lookup. Right now we dont' have a good way 536 // of going between IdentifierInfo* and the class hierarchy. 537 MapTy::iterator I = M.find(ObjCSummaryKey(II, S)); 538 539 if (I == M.end()) 540 I = M.find(ObjCSummaryKey(S)); 541 542 return I == M.end() ? NULL : I->second; 543 } 544 545 const RetainSummary *& operator[](ObjCSummaryKey K) { 546 return M[K]; 547 } 548 549 const RetainSummary *& operator[](Selector S) { 550 return M[ ObjCSummaryKey(S) ]; 551 } 552}; 553} // end anonymous namespace 554 555//===----------------------------------------------------------------------===// 556// Data structures for managing collections of summaries. 557//===----------------------------------------------------------------------===// 558 559namespace { 560class RetainSummaryManager { 561 562 //==-----------------------------------------------------------------==// 563 // Typedefs. 564 //==-----------------------------------------------------------------==// 565 566 typedef llvm::DenseMap<const FunctionDecl*, const RetainSummary *> 567 FuncSummariesTy; 568 569 typedef ObjCSummaryCache ObjCMethodSummariesTy; 570 571 typedef llvm::FoldingSetNodeWrapper<RetainSummary> CachedSummaryNode; 572 573 //==-----------------------------------------------------------------==// 574 // Data. 575 //==-----------------------------------------------------------------==// 576 577 /// Ctx - The ASTContext object for the analyzed ASTs. 578 ASTContext &Ctx; 579 580 /// GCEnabled - Records whether or not the analyzed code runs in GC mode. 581 const bool GCEnabled; 582 583 /// Records whether or not the analyzed code runs in ARC mode. 584 const bool ARCEnabled; 585 586 /// FuncSummaries - A map from FunctionDecls to summaries. 587 FuncSummariesTy FuncSummaries; 588 589 /// ObjCClassMethodSummaries - A map from selectors (for instance methods) 590 /// to summaries. 591 ObjCMethodSummariesTy ObjCClassMethodSummaries; 592 593 /// ObjCMethodSummaries - A map from selectors to summaries. 594 ObjCMethodSummariesTy ObjCMethodSummaries; 595 596 /// BPAlloc - A BumpPtrAllocator used for allocating summaries, ArgEffects, 597 /// and all other data used by the checker. 598 llvm::BumpPtrAllocator BPAlloc; 599 600 /// AF - A factory for ArgEffects objects. 601 ArgEffects::Factory AF; 602 603 /// ScratchArgs - A holding buffer for construct ArgEffects. 604 ArgEffects ScratchArgs; 605 606 /// ObjCAllocRetE - Default return effect for methods returning Objective-C 607 /// objects. 608 RetEffect ObjCAllocRetE; 609 610 /// ObjCInitRetE - Default return effect for init methods returning 611 /// Objective-C objects. 612 RetEffect ObjCInitRetE; 613 614 /// SimpleSummaries - Used for uniquing summaries that don't have special 615 /// effects. 616 llvm::FoldingSet<CachedSummaryNode> SimpleSummaries; 617 618 //==-----------------------------------------------------------------==// 619 // Methods. 620 //==-----------------------------------------------------------------==// 621 622 /// getArgEffects - Returns a persistent ArgEffects object based on the 623 /// data in ScratchArgs. 624 ArgEffects getArgEffects(); 625 626 enum UnaryFuncKind { cfretain, cfrelease, cfmakecollectable }; 627 628 const RetainSummary *getUnarySummary(const FunctionType* FT, 629 UnaryFuncKind func); 630 631 const RetainSummary *getCFSummaryCreateRule(const FunctionDecl *FD); 632 const RetainSummary *getCFSummaryGetRule(const FunctionDecl *FD); 633 const RetainSummary *getCFCreateGetRuleSummary(const FunctionDecl *FD); 634 635 const RetainSummary *getPersistentSummary(const RetainSummary &OldSumm); 636 637 const RetainSummary *getPersistentSummary(RetEffect RetEff, 638 ArgEffect ReceiverEff = DoNothing, 639 ArgEffect DefaultEff = MayEscape) { 640 RetainSummary Summ(getArgEffects(), RetEff, DefaultEff, ReceiverEff); 641 return getPersistentSummary(Summ); 642 } 643 644 const RetainSummary *getDoNothingSummary() { 645 return getPersistentSummary(RetEffect::MakeNoRet(), DoNothing, DoNothing); 646 } 647 648 const RetainSummary *getDefaultSummary() { 649 return getPersistentSummary(RetEffect::MakeNoRet(), 650 DoNothing, MayEscape); 651 } 652 653 const RetainSummary *getPersistentStopSummary() { 654 return getPersistentSummary(RetEffect::MakeNoRet(), 655 StopTracking, StopTracking); 656 } 657 658 void InitializeClassMethodSummaries(); 659 void InitializeMethodSummaries(); 660private: 661 void addNSObjectClsMethSummary(Selector S, const RetainSummary *Summ) { 662 ObjCClassMethodSummaries[S] = Summ; 663 } 664 665 void addNSObjectMethSummary(Selector S, const RetainSummary *Summ) { 666 ObjCMethodSummaries[S] = Summ; 667 } 668 669 void addClassMethSummary(const char* Cls, const char* name, 670 const RetainSummary *Summ, bool isNullary = true) { 671 IdentifierInfo* ClsII = &Ctx.Idents.get(Cls); 672 Selector S = isNullary ? GetNullarySelector(name, Ctx) 673 : GetUnarySelector(name, Ctx); 674 ObjCClassMethodSummaries[ObjCSummaryKey(ClsII, S)] = Summ; 675 } 676 677 void addInstMethSummary(const char* Cls, const char* nullaryName, 678 const RetainSummary *Summ) { 679 IdentifierInfo* ClsII = &Ctx.Idents.get(Cls); 680 Selector S = GetNullarySelector(nullaryName, Ctx); 681 ObjCMethodSummaries[ObjCSummaryKey(ClsII, S)] = Summ; 682 } 683 684 Selector generateSelector(va_list argp) { 685 SmallVector<IdentifierInfo*, 10> II; 686 687 while (const char* s = va_arg(argp, const char*)) 688 II.push_back(&Ctx.Idents.get(s)); 689 690 return Ctx.Selectors.getSelector(II.size(), &II[0]); 691 } 692 693 void addMethodSummary(IdentifierInfo *ClsII, ObjCMethodSummariesTy& Summaries, 694 const RetainSummary * Summ, va_list argp) { 695 Selector S = generateSelector(argp); 696 Summaries[ObjCSummaryKey(ClsII, S)] = Summ; 697 } 698 699 void addInstMethSummary(const char* Cls, const RetainSummary * Summ, ...) { 700 va_list argp; 701 va_start(argp, Summ); 702 addMethodSummary(&Ctx.Idents.get(Cls), ObjCMethodSummaries, Summ, argp); 703 va_end(argp); 704 } 705 706 void addClsMethSummary(const char* Cls, const RetainSummary * Summ, ...) { 707 va_list argp; 708 va_start(argp, Summ); 709 addMethodSummary(&Ctx.Idents.get(Cls),ObjCClassMethodSummaries, Summ, argp); 710 va_end(argp); 711 } 712 713 void addClsMethSummary(IdentifierInfo *II, const RetainSummary * Summ, ...) { 714 va_list argp; 715 va_start(argp, Summ); 716 addMethodSummary(II, ObjCClassMethodSummaries, Summ, argp); 717 va_end(argp); 718 } 719 720public: 721 722 RetainSummaryManager(ASTContext &ctx, bool gcenabled, bool usesARC) 723 : Ctx(ctx), 724 GCEnabled(gcenabled), 725 ARCEnabled(usesARC), 726 AF(BPAlloc), ScratchArgs(AF.getEmptyMap()), 727 ObjCAllocRetE(gcenabled 728 ? RetEffect::MakeGCNotOwned() 729 : (usesARC ? RetEffect::MakeARCNotOwned() 730 : RetEffect::MakeOwned(RetEffect::ObjC, true))), 731 ObjCInitRetE(gcenabled 732 ? RetEffect::MakeGCNotOwned() 733 : (usesARC ? RetEffect::MakeARCNotOwned() 734 : RetEffect::MakeOwnedWhenTrackedReceiver())) { 735 InitializeClassMethodSummaries(); 736 InitializeMethodSummaries(); 737 } 738 739 const RetainSummary *getSummary(const CallEvent &Call, 740 ProgramStateRef State = 0); 741 742 const RetainSummary *getFunctionSummary(const FunctionDecl *FD); 743 744 const RetainSummary *getMethodSummary(Selector S, const ObjCInterfaceDecl *ID, 745 const ObjCMethodDecl *MD, 746 QualType RetTy, 747 ObjCMethodSummariesTy &CachedSummaries); 748 749 const RetainSummary *getInstanceMethodSummary(const ObjCMethodCall &M, 750 ProgramStateRef State); 751 752 const RetainSummary *getClassMethodSummary(const ObjCMethodCall &M) { 753 assert(!M.isInstanceMessage()); 754 const ObjCInterfaceDecl *Class = M.getReceiverInterface(); 755 756 return getMethodSummary(M.getSelector(), Class, M.getDecl(), 757 M.getResultType(), ObjCClassMethodSummaries); 758 } 759 760 /// getMethodSummary - This version of getMethodSummary is used to query 761 /// the summary for the current method being analyzed. 762 const RetainSummary *getMethodSummary(const ObjCMethodDecl *MD) { 763 const ObjCInterfaceDecl *ID = MD->getClassInterface(); 764 Selector S = MD->getSelector(); 765 QualType ResultTy = MD->getResultType(); 766 767 ObjCMethodSummariesTy *CachedSummaries; 768 if (MD->isInstanceMethod()) 769 CachedSummaries = &ObjCMethodSummaries; 770 else 771 CachedSummaries = &ObjCClassMethodSummaries; 772 773 return getMethodSummary(S, ID, MD, ResultTy, *CachedSummaries); 774 } 775 776 const RetainSummary *getStandardMethodSummary(const ObjCMethodDecl *MD, 777 Selector S, QualType RetTy); 778 779 void updateSummaryFromAnnotations(const RetainSummary *&Summ, 780 const ObjCMethodDecl *MD); 781 782 void updateSummaryFromAnnotations(const RetainSummary *&Summ, 783 const FunctionDecl *FD); 784 785 void updateSummaryForCall(const RetainSummary *&Summ, 786 const CallEvent &Call); 787 788 bool isGCEnabled() const { return GCEnabled; } 789 790 bool isARCEnabled() const { return ARCEnabled; } 791 792 bool isARCorGCEnabled() const { return GCEnabled || ARCEnabled; } 793 794 RetEffect getObjAllocRetEffect() const { return ObjCAllocRetE; } 795 796 friend class RetainSummaryTemplate; 797}; 798 799// Used to avoid allocating long-term (BPAlloc'd) memory for default retain 800// summaries. If a function or method looks like it has a default summary, but 801// it has annotations, the annotations are added to the stack-based template 802// and then copied into managed memory. 803class RetainSummaryTemplate { 804 RetainSummaryManager &Manager; 805 const RetainSummary *&RealSummary; 806 RetainSummary ScratchSummary; 807 bool Accessed; 808public: 809 RetainSummaryTemplate(const RetainSummary *&real, RetainSummaryManager &mgr) 810 : Manager(mgr), RealSummary(real), ScratchSummary(*real), Accessed(false) {} 811 812 ~RetainSummaryTemplate() { 813 if (Accessed) 814 RealSummary = Manager.getPersistentSummary(ScratchSummary); 815 } 816 817 RetainSummary &operator*() { 818 Accessed = true; 819 return ScratchSummary; 820 } 821 822 RetainSummary *operator->() { 823 Accessed = true; 824 return &ScratchSummary; 825 } 826}; 827 828} // end anonymous namespace 829 830//===----------------------------------------------------------------------===// 831// Implementation of checker data structures. 832//===----------------------------------------------------------------------===// 833 834ArgEffects RetainSummaryManager::getArgEffects() { 835 ArgEffects AE = ScratchArgs; 836 ScratchArgs = AF.getEmptyMap(); 837 return AE; 838} 839 840const RetainSummary * 841RetainSummaryManager::getPersistentSummary(const RetainSummary &OldSumm) { 842 // Unique "simple" summaries -- those without ArgEffects. 843 if (OldSumm.isSimple()) { 844 llvm::FoldingSetNodeID ID; 845 OldSumm.Profile(ID); 846 847 void *Pos; 848 CachedSummaryNode *N = SimpleSummaries.FindNodeOrInsertPos(ID, Pos); 849 850 if (!N) { 851 N = (CachedSummaryNode *) BPAlloc.Allocate<CachedSummaryNode>(); 852 new (N) CachedSummaryNode(OldSumm); 853 SimpleSummaries.InsertNode(N, Pos); 854 } 855 856 return &N->getValue(); 857 } 858 859 RetainSummary *Summ = (RetainSummary *) BPAlloc.Allocate<RetainSummary>(); 860 new (Summ) RetainSummary(OldSumm); 861 return Summ; 862} 863 864//===----------------------------------------------------------------------===// 865// Summary creation for functions (largely uses of Core Foundation). 866//===----------------------------------------------------------------------===// 867 868static bool isRetain(const FunctionDecl *FD, StringRef FName) { 869 return FName.endswith("Retain"); 870} 871 872static bool isRelease(const FunctionDecl *FD, StringRef FName) { 873 return FName.endswith("Release"); 874} 875 876static bool isMakeCollectable(const FunctionDecl *FD, StringRef FName) { 877 // FIXME: Remove FunctionDecl parameter. 878 // FIXME: Is it really okay if MakeCollectable isn't a suffix? 879 return FName.find("MakeCollectable") != StringRef::npos; 880} 881 882static ArgEffect getStopTrackingEquivalent(ArgEffect E) { 883 switch (E) { 884 case DoNothing: 885 case Autorelease: 886 case DecRefBridgedTransfered: 887 case IncRef: 888 case IncRefMsg: 889 case MakeCollectable: 890 case MayEscape: 891 case NewAutoreleasePool: 892 case StopTracking: 893 return StopTracking; 894 case DecRef: 895 case DecRefAndStopTracking: 896 return DecRefAndStopTracking; 897 case DecRefMsg: 898 case DecRefMsgAndStopTracking: 899 return DecRefMsgAndStopTracking; 900 case Dealloc: 901 return Dealloc; 902 } 903 904 llvm_unreachable("Unknown ArgEffect kind"); 905} 906 907void RetainSummaryManager::updateSummaryForCall(const RetainSummary *&S, 908 const CallEvent &Call) { 909 if (Call.hasNonZeroCallbackArg()) { 910 ArgEffect RecEffect = getStopTrackingEquivalent(S->getReceiverEffect()); 911 ArgEffect DefEffect = getStopTrackingEquivalent(S->getDefaultArgEffect()); 912 913 ArgEffects CustomArgEffects = S->getArgEffects(); 914 for (ArgEffects::iterator I = CustomArgEffects.begin(), 915 E = CustomArgEffects.end(); 916 I != E; ++I) { 917 ArgEffect Translated = getStopTrackingEquivalent(I->second); 918 if (Translated != DefEffect) 919 ScratchArgs = AF.add(ScratchArgs, I->first, Translated); 920 } 921 922 RetEffect RE = RetEffect::MakeNoRet(); 923 924 // Special cases where the callback argument CANNOT free the return value. 925 // This can generally only happen if we know that the callback will only be 926 // called when the return value is already being deallocated. 927 if (const FunctionCall *FC = dyn_cast<FunctionCall>(&Call)) { 928 IdentifierInfo *Name = FC->getDecl()->getIdentifier(); 929 930 // This callback frees the associated buffer. 931 if (Name->isStr("CGBitmapContextCreateWithData")) 932 RE = S->getRetEffect(); 933 } 934 935 S = getPersistentSummary(RE, RecEffect, DefEffect); 936 } 937} 938 939const RetainSummary * 940RetainSummaryManager::getSummary(const CallEvent &Call, 941 ProgramStateRef State) { 942 const RetainSummary *Summ; 943 switch (Call.getKind()) { 944 case CE_Function: 945 Summ = getFunctionSummary(cast<FunctionCall>(Call).getDecl()); 946 break; 947 case CE_CXXMember: 948 case CE_CXXMemberOperator: 949 case CE_Block: 950 case CE_CXXConstructor: 951 case CE_CXXDestructor: 952 case CE_CXXAllocator: 953 // FIXME: These calls are currently unsupported. 954 return getPersistentStopSummary(); 955 case CE_ObjCMessage: { 956 const ObjCMethodCall &Msg = cast<ObjCMethodCall>(Call); 957 if (Msg.isInstanceMessage()) 958 Summ = getInstanceMethodSummary(Msg, State); 959 else 960 Summ = getClassMethodSummary(Msg); 961 break; 962 } 963 } 964 965 updateSummaryForCall(Summ, Call); 966 967 assert(Summ && "Unknown call type?"); 968 return Summ; 969} 970 971const RetainSummary * 972RetainSummaryManager::getFunctionSummary(const FunctionDecl *FD) { 973 // If we don't know what function we're calling, use our default summary. 974 if (!FD) 975 return getDefaultSummary(); 976 977 // Look up a summary in our cache of FunctionDecls -> Summaries. 978 FuncSummariesTy::iterator I = FuncSummaries.find(FD); 979 if (I != FuncSummaries.end()) 980 return I->second; 981 982 // No summary? Generate one. 983 const RetainSummary *S = 0; 984 bool AllowAnnotations = true; 985 986 do { 987 // We generate "stop" summaries for implicitly defined functions. 988 if (FD->isImplicit()) { 989 S = getPersistentStopSummary(); 990 break; 991 } 992 993 // [PR 3337] Use 'getAs<FunctionType>' to strip away any typedefs on the 994 // function's type. 995 const FunctionType* FT = FD->getType()->getAs<FunctionType>(); 996 const IdentifierInfo *II = FD->getIdentifier(); 997 if (!II) 998 break; 999 1000 StringRef FName = II->getName(); 1001 1002 // Strip away preceding '_'. Doing this here will effect all the checks 1003 // down below. 1004 FName = FName.substr(FName.find_first_not_of('_')); 1005 1006 // Inspect the result type. 1007 QualType RetTy = FT->getResultType(); 1008 1009 // FIXME: This should all be refactored into a chain of "summary lookup" 1010 // filters. 1011 assert(ScratchArgs.isEmpty()); 1012 1013 if (FName == "pthread_create" || FName == "pthread_setspecific") { 1014 // Part of: <rdar://problem/7299394> and <rdar://problem/11282706>. 1015 // This will be addressed better with IPA. 1016 S = getPersistentStopSummary(); 1017 } else if (FName == "NSMakeCollectable") { 1018 // Handle: id NSMakeCollectable(CFTypeRef) 1019 S = (RetTy->isObjCIdType()) 1020 ? getUnarySummary(FT, cfmakecollectable) 1021 : getPersistentStopSummary(); 1022 // The headers on OS X 10.8 use cf_consumed/ns_returns_retained, 1023 // but we can fully model NSMakeCollectable ourselves. 1024 AllowAnnotations = false; 1025 } else if (FName == "IOBSDNameMatching" || 1026 FName == "IOServiceMatching" || 1027 FName == "IOServiceNameMatching" || 1028 FName == "IORegistryEntrySearchCFProperty" || 1029 FName == "IORegistryEntryIDMatching" || 1030 FName == "IOOpenFirmwarePathMatching") { 1031 // Part of <rdar://problem/6961230>. (IOKit) 1032 // This should be addressed using a API table. 1033 S = getPersistentSummary(RetEffect::MakeOwned(RetEffect::CF, true), 1034 DoNothing, DoNothing); 1035 } else if (FName == "IOServiceGetMatchingService" || 1036 FName == "IOServiceGetMatchingServices") { 1037 // FIXES: <rdar://problem/6326900> 1038 // This should be addressed using a API table. This strcmp is also 1039 // a little gross, but there is no need to super optimize here. 1040 ScratchArgs = AF.add(ScratchArgs, 1, DecRef); 1041 S = getPersistentSummary(RetEffect::MakeNoRet(), DoNothing, DoNothing); 1042 } else if (FName == "IOServiceAddNotification" || 1043 FName == "IOServiceAddMatchingNotification") { 1044 // Part of <rdar://problem/6961230>. (IOKit) 1045 // This should be addressed using a API table. 1046 ScratchArgs = AF.add(ScratchArgs, 2, DecRef); 1047 S = getPersistentSummary(RetEffect::MakeNoRet(), DoNothing, DoNothing); 1048 } else if (FName == "CVPixelBufferCreateWithBytes") { 1049 // FIXES: <rdar://problem/7283567> 1050 // Eventually this can be improved by recognizing that the pixel 1051 // buffer passed to CVPixelBufferCreateWithBytes is released via 1052 // a callback and doing full IPA to make sure this is done correctly. 1053 // FIXME: This function has an out parameter that returns an 1054 // allocated object. 1055 ScratchArgs = AF.add(ScratchArgs, 7, StopTracking); 1056 S = getPersistentSummary(RetEffect::MakeNoRet(), DoNothing, DoNothing); 1057 } else if (FName == "CGBitmapContextCreateWithData") { 1058 // FIXES: <rdar://problem/7358899> 1059 // Eventually this can be improved by recognizing that 'releaseInfo' 1060 // passed to CGBitmapContextCreateWithData is released via 1061 // a callback and doing full IPA to make sure this is done correctly. 1062 ScratchArgs = AF.add(ScratchArgs, 8, StopTracking); 1063 S = getPersistentSummary(RetEffect::MakeOwned(RetEffect::CF, true), 1064 DoNothing, DoNothing); 1065 } else if (FName == "CVPixelBufferCreateWithPlanarBytes") { 1066 // FIXES: <rdar://problem/7283567> 1067 // Eventually this can be improved by recognizing that the pixel 1068 // buffer passed to CVPixelBufferCreateWithPlanarBytes is released 1069 // via a callback and doing full IPA to make sure this is done 1070 // correctly. 1071 ScratchArgs = AF.add(ScratchArgs, 12, StopTracking); 1072 S = getPersistentSummary(RetEffect::MakeNoRet(), DoNothing, DoNothing); 1073 } else if (FName == "dispatch_set_context") { 1074 // <rdar://problem/11059275> - The analyzer currently doesn't have 1075 // a good way to reason about the finalizer function for libdispatch. 1076 // If we pass a context object that is memory managed, stop tracking it. 1077 // FIXME: this hack should possibly go away once we can handle 1078 // libdispatch finalizers. 1079 ScratchArgs = AF.add(ScratchArgs, 1, StopTracking); 1080 S = getPersistentSummary(RetEffect::MakeNoRet(), DoNothing, DoNothing); 1081 } else if (FName.startswith("NSLog")) { 1082 S = getDoNothingSummary(); 1083 } else if (FName.startswith("NS") && 1084 (FName.find("Insert") != StringRef::npos)) { 1085 // Whitelist NSXXInsertXX, for example NSMapInsertIfAbsent, since they can 1086 // be deallocated by NSMapRemove. (radar://11152419) 1087 ScratchArgs = AF.add(ScratchArgs, 1, StopTracking); 1088 ScratchArgs = AF.add(ScratchArgs, 2, StopTracking); 1089 S = getPersistentSummary(RetEffect::MakeNoRet(), DoNothing, DoNothing); 1090 } 1091 1092 // Did we get a summary? 1093 if (S) 1094 break; 1095 1096 // Enable this code once the semantics of NSDeallocateObject are resolved 1097 // for GC. <rdar://problem/6619988> 1098#if 0 1099 // Handle: NSDeallocateObject(id anObject); 1100 // This method does allow 'nil' (although we don't check it now). 1101 if (strcmp(FName, "NSDeallocateObject") == 0) { 1102 return RetTy == Ctx.VoidTy 1103 ? getPersistentSummary(RetEffect::MakeNoRet(), DoNothing, Dealloc) 1104 : getPersistentStopSummary(); 1105 } 1106#endif 1107 1108 if (RetTy->isPointerType()) { 1109 // For CoreFoundation ('CF') types. 1110 if (cocoa::isRefType(RetTy, "CF", FName)) { 1111 if (isRetain(FD, FName)) 1112 S = getUnarySummary(FT, cfretain); 1113 else if (isMakeCollectable(FD, FName)) 1114 S = getUnarySummary(FT, cfmakecollectable); 1115 else 1116 S = getCFCreateGetRuleSummary(FD); 1117 1118 break; 1119 } 1120 1121 // For CoreGraphics ('CG') types. 1122 if (cocoa::isRefType(RetTy, "CG", FName)) { 1123 if (isRetain(FD, FName)) 1124 S = getUnarySummary(FT, cfretain); 1125 else 1126 S = getCFCreateGetRuleSummary(FD); 1127 1128 break; 1129 } 1130 1131 // For the Disk Arbitration API (DiskArbitration/DADisk.h) 1132 if (cocoa::isRefType(RetTy, "DADisk") || 1133 cocoa::isRefType(RetTy, "DADissenter") || 1134 cocoa::isRefType(RetTy, "DASessionRef")) { 1135 S = getCFCreateGetRuleSummary(FD); 1136 break; 1137 } 1138 1139 break; 1140 } 1141 1142 // Check for release functions, the only kind of functions that we care 1143 // about that don't return a pointer type. 1144 if (FName[0] == 'C' && (FName[1] == 'F' || FName[1] == 'G')) { 1145 // Test for 'CGCF'. 1146 FName = FName.substr(FName.startswith("CGCF") ? 4 : 2); 1147 1148 if (isRelease(FD, FName)) 1149 S = getUnarySummary(FT, cfrelease); 1150 else { 1151 assert (ScratchArgs.isEmpty()); 1152 // Remaining CoreFoundation and CoreGraphics functions. 1153 // We use to assume that they all strictly followed the ownership idiom 1154 // and that ownership cannot be transferred. While this is technically 1155 // correct, many methods allow a tracked object to escape. For example: 1156 // 1157 // CFMutableDictionaryRef x = CFDictionaryCreateMutable(...); 1158 // CFDictionaryAddValue(y, key, x); 1159 // CFRelease(x); 1160 // ... it is okay to use 'x' since 'y' has a reference to it 1161 // 1162 // We handle this and similar cases with the follow heuristic. If the 1163 // function name contains "InsertValue", "SetValue", "AddValue", 1164 // "AppendValue", or "SetAttribute", then we assume that arguments may 1165 // "escape." This means that something else holds on to the object, 1166 // allowing it be used even after its local retain count drops to 0. 1167 ArgEffect E = (StrInStrNoCase(FName, "InsertValue") != StringRef::npos|| 1168 StrInStrNoCase(FName, "AddValue") != StringRef::npos || 1169 StrInStrNoCase(FName, "SetValue") != StringRef::npos || 1170 StrInStrNoCase(FName, "AppendValue") != StringRef::npos|| 1171 StrInStrNoCase(FName, "SetAttribute") != StringRef::npos) 1172 ? MayEscape : DoNothing; 1173 1174 S = getPersistentSummary(RetEffect::MakeNoRet(), DoNothing, E); 1175 } 1176 } 1177 } 1178 while (0); 1179 1180 // If we got all the way here without any luck, use a default summary. 1181 if (!S) 1182 S = getDefaultSummary(); 1183 1184 // Annotations override defaults. 1185 if (AllowAnnotations) 1186 updateSummaryFromAnnotations(S, FD); 1187 1188 FuncSummaries[FD] = S; 1189 return S; 1190} 1191 1192const RetainSummary * 1193RetainSummaryManager::getCFCreateGetRuleSummary(const FunctionDecl *FD) { 1194 if (coreFoundation::followsCreateRule(FD)) 1195 return getCFSummaryCreateRule(FD); 1196 1197 return getCFSummaryGetRule(FD); 1198} 1199 1200const RetainSummary * 1201RetainSummaryManager::getUnarySummary(const FunctionType* FT, 1202 UnaryFuncKind func) { 1203 1204 // Sanity check that this is *really* a unary function. This can 1205 // happen if people do weird things. 1206 const FunctionProtoType* FTP = dyn_cast<FunctionProtoType>(FT); 1207 if (!FTP || FTP->getNumArgs() != 1) 1208 return getPersistentStopSummary(); 1209 1210 assert (ScratchArgs.isEmpty()); 1211 1212 ArgEffect Effect; 1213 switch (func) { 1214 case cfretain: Effect = IncRef; break; 1215 case cfrelease: Effect = DecRef; break; 1216 case cfmakecollectable: Effect = MakeCollectable; break; 1217 } 1218 1219 ScratchArgs = AF.add(ScratchArgs, 0, Effect); 1220 return getPersistentSummary(RetEffect::MakeNoRet(), DoNothing, DoNothing); 1221} 1222 1223const RetainSummary * 1224RetainSummaryManager::getCFSummaryCreateRule(const FunctionDecl *FD) { 1225 assert (ScratchArgs.isEmpty()); 1226 1227 return getPersistentSummary(RetEffect::MakeOwned(RetEffect::CF, true)); 1228} 1229 1230const RetainSummary * 1231RetainSummaryManager::getCFSummaryGetRule(const FunctionDecl *FD) { 1232 assert (ScratchArgs.isEmpty()); 1233 return getPersistentSummary(RetEffect::MakeNotOwned(RetEffect::CF), 1234 DoNothing, DoNothing); 1235} 1236 1237//===----------------------------------------------------------------------===// 1238// Summary creation for Selectors. 1239//===----------------------------------------------------------------------===// 1240 1241void 1242RetainSummaryManager::updateSummaryFromAnnotations(const RetainSummary *&Summ, 1243 const FunctionDecl *FD) { 1244 if (!FD) 1245 return; 1246 1247 assert(Summ && "Must have a summary to add annotations to."); 1248 RetainSummaryTemplate Template(Summ, *this); 1249 1250 // Effects on the parameters. 1251 unsigned parm_idx = 0; 1252 for (FunctionDecl::param_const_iterator pi = FD->param_begin(), 1253 pe = FD->param_end(); pi != pe; ++pi, ++parm_idx) { 1254 const ParmVarDecl *pd = *pi; 1255 if (pd->getAttr<NSConsumedAttr>()) { 1256 if (!GCEnabled) { 1257 Template->addArg(AF, parm_idx, DecRef); 1258 } 1259 } else if (pd->getAttr<CFConsumedAttr>()) { 1260 Template->addArg(AF, parm_idx, DecRef); 1261 } 1262 } 1263 1264 QualType RetTy = FD->getResultType(); 1265 1266 // Determine if there is a special return effect for this method. 1267 if (cocoa::isCocoaObjectRef(RetTy)) { 1268 if (FD->getAttr<NSReturnsRetainedAttr>()) { 1269 Template->setRetEffect(ObjCAllocRetE); 1270 } 1271 else if (FD->getAttr<CFReturnsRetainedAttr>()) { 1272 Template->setRetEffect(RetEffect::MakeOwned(RetEffect::CF, true)); 1273 } 1274 else if (FD->getAttr<NSReturnsNotRetainedAttr>()) { 1275 Template->setRetEffect(RetEffect::MakeNotOwned(RetEffect::ObjC)); 1276 } 1277 else if (FD->getAttr<CFReturnsNotRetainedAttr>()) { 1278 Template->setRetEffect(RetEffect::MakeNotOwned(RetEffect::CF)); 1279 } 1280 } else if (RetTy->getAs<PointerType>()) { 1281 if (FD->getAttr<CFReturnsRetainedAttr>()) { 1282 Template->setRetEffect(RetEffect::MakeOwned(RetEffect::CF, true)); 1283 } 1284 else if (FD->getAttr<CFReturnsNotRetainedAttr>()) { 1285 Template->setRetEffect(RetEffect::MakeNotOwned(RetEffect::CF)); 1286 } 1287 } 1288} 1289 1290void 1291RetainSummaryManager::updateSummaryFromAnnotations(const RetainSummary *&Summ, 1292 const ObjCMethodDecl *MD) { 1293 if (!MD) 1294 return; 1295 1296 assert(Summ && "Must have a valid summary to add annotations to"); 1297 RetainSummaryTemplate Template(Summ, *this); 1298 bool isTrackedLoc = false; 1299 1300 // Effects on the receiver. 1301 if (MD->getAttr<NSConsumesSelfAttr>()) { 1302 if (!GCEnabled) 1303 Template->setReceiverEffect(DecRefMsg); 1304 } 1305 1306 // Effects on the parameters. 1307 unsigned parm_idx = 0; 1308 for (ObjCMethodDecl::param_const_iterator 1309 pi=MD->param_begin(), pe=MD->param_end(); 1310 pi != pe; ++pi, ++parm_idx) { 1311 const ParmVarDecl *pd = *pi; 1312 if (pd->getAttr<NSConsumedAttr>()) { 1313 if (!GCEnabled) 1314 Template->addArg(AF, parm_idx, DecRef); 1315 } 1316 else if(pd->getAttr<CFConsumedAttr>()) { 1317 Template->addArg(AF, parm_idx, DecRef); 1318 } 1319 } 1320 1321 // Determine if there is a special return effect for this method. 1322 if (cocoa::isCocoaObjectRef(MD->getResultType())) { 1323 if (MD->getAttr<NSReturnsRetainedAttr>()) { 1324 Template->setRetEffect(ObjCAllocRetE); 1325 return; 1326 } 1327 if (MD->getAttr<NSReturnsNotRetainedAttr>()) { 1328 Template->setRetEffect(RetEffect::MakeNotOwned(RetEffect::ObjC)); 1329 return; 1330 } 1331 1332 isTrackedLoc = true; 1333 } else { 1334 isTrackedLoc = MD->getResultType()->getAs<PointerType>() != NULL; 1335 } 1336 1337 if (isTrackedLoc) { 1338 if (MD->getAttr<CFReturnsRetainedAttr>()) 1339 Template->setRetEffect(RetEffect::MakeOwned(RetEffect::CF, true)); 1340 else if (MD->getAttr<CFReturnsNotRetainedAttr>()) 1341 Template->setRetEffect(RetEffect::MakeNotOwned(RetEffect::CF)); 1342 } 1343} 1344 1345const RetainSummary * 1346RetainSummaryManager::getStandardMethodSummary(const ObjCMethodDecl *MD, 1347 Selector S, QualType RetTy) { 1348 1349 if (MD) { 1350 // Scan the method decl for 'void*' arguments. These should be treated 1351 // as 'StopTracking' because they are often used with delegates. 1352 // Delegates are a frequent form of false positives with the retain 1353 // count checker. 1354 unsigned i = 0; 1355 for (ObjCMethodDecl::param_const_iterator I = MD->param_begin(), 1356 E = MD->param_end(); I != E; ++I, ++i) 1357 if (const ParmVarDecl *PD = *I) { 1358 QualType Ty = Ctx.getCanonicalType(PD->getType()); 1359 if (Ty.getLocalUnqualifiedType() == Ctx.VoidPtrTy) 1360 ScratchArgs = AF.add(ScratchArgs, i, StopTracking); 1361 } 1362 } 1363 1364 // Any special effects? 1365 ArgEffect ReceiverEff = DoNothing; 1366 RetEffect ResultEff = RetEffect::MakeNoRet(); 1367 1368 // Check the method family, and apply any default annotations. 1369 switch (MD ? MD->getMethodFamily() : S.getMethodFamily()) { 1370 case OMF_None: 1371 case OMF_performSelector: 1372 // Assume all Objective-C methods follow Cocoa Memory Management rules. 1373 // FIXME: Does the non-threaded performSelector family really belong here? 1374 // The selector could be, say, @selector(copy). 1375 if (cocoa::isCocoaObjectRef(RetTy)) 1376 ResultEff = RetEffect::MakeNotOwned(RetEffect::ObjC); 1377 else if (coreFoundation::isCFObjectRef(RetTy)) { 1378 // ObjCMethodDecl currently doesn't consider CF objects as valid return 1379 // values for alloc, new, copy, or mutableCopy, so we have to 1380 // double-check with the selector. This is ugly, but there aren't that 1381 // many Objective-C methods that return CF objects, right? 1382 if (MD) { 1383 switch (S.getMethodFamily()) { 1384 case OMF_alloc: 1385 case OMF_new: 1386 case OMF_copy: 1387 case OMF_mutableCopy: 1388 ResultEff = RetEffect::MakeOwned(RetEffect::CF, true); 1389 break; 1390 default: 1391 ResultEff = RetEffect::MakeNotOwned(RetEffect::CF); 1392 break; 1393 } 1394 } else { 1395 ResultEff = RetEffect::MakeNotOwned(RetEffect::CF); 1396 } 1397 } 1398 break; 1399 case OMF_init: 1400 ResultEff = ObjCInitRetE; 1401 ReceiverEff = DecRefMsg; 1402 break; 1403 case OMF_alloc: 1404 case OMF_new: 1405 case OMF_copy: 1406 case OMF_mutableCopy: 1407 if (cocoa::isCocoaObjectRef(RetTy)) 1408 ResultEff = ObjCAllocRetE; 1409 else if (coreFoundation::isCFObjectRef(RetTy)) 1410 ResultEff = RetEffect::MakeOwned(RetEffect::CF, true); 1411 break; 1412 case OMF_autorelease: 1413 ReceiverEff = Autorelease; 1414 break; 1415 case OMF_retain: 1416 ReceiverEff = IncRefMsg; 1417 break; 1418 case OMF_release: 1419 ReceiverEff = DecRefMsg; 1420 break; 1421 case OMF_dealloc: 1422 ReceiverEff = Dealloc; 1423 break; 1424 case OMF_self: 1425 // -self is handled specially by the ExprEngine to propagate the receiver. 1426 break; 1427 case OMF_retainCount: 1428 case OMF_finalize: 1429 // These methods don't return objects. 1430 break; 1431 } 1432 1433 // If one of the arguments in the selector has the keyword 'delegate' we 1434 // should stop tracking the reference count for the receiver. This is 1435 // because the reference count is quite possibly handled by a delegate 1436 // method. 1437 if (S.isKeywordSelector()) { 1438 for (unsigned i = 0, e = S.getNumArgs(); i != e; ++i) { 1439 StringRef Slot = S.getNameForSlot(i); 1440 if (Slot.substr(Slot.size() - 8).equals_lower("delegate")) { 1441 if (ResultEff == ObjCInitRetE) 1442 ResultEff = RetEffect::MakeNoRet(); 1443 else 1444 ReceiverEff = StopTracking; 1445 } 1446 } 1447 } 1448 1449 if (ScratchArgs.isEmpty() && ReceiverEff == DoNothing && 1450 ResultEff.getKind() == RetEffect::NoRet) 1451 return getDefaultSummary(); 1452 1453 return getPersistentSummary(ResultEff, ReceiverEff, MayEscape); 1454} 1455 1456const RetainSummary * 1457RetainSummaryManager::getInstanceMethodSummary(const ObjCMethodCall &Msg, 1458 ProgramStateRef State) { 1459 const ObjCInterfaceDecl *ReceiverClass = 0; 1460 1461 // We do better tracking of the type of the object than the core ExprEngine. 1462 // See if we have its type in our private state. 1463 // FIXME: Eventually replace the use of state->get<RefBindings> with 1464 // a generic API for reasoning about the Objective-C types of symbolic 1465 // objects. 1466 SVal ReceiverV = Msg.getReceiverSVal(); 1467 if (SymbolRef Sym = ReceiverV.getAsLocSymbol()) 1468 if (const RefVal *T = State->get<RefBindings>(Sym)) 1469 if (const ObjCObjectPointerType *PT = 1470 T->getType()->getAs<ObjCObjectPointerType>()) 1471 ReceiverClass = PT->getInterfaceDecl(); 1472 1473 // If we don't know what kind of object this is, fall back to its static type. 1474 if (!ReceiverClass) 1475 ReceiverClass = Msg.getReceiverInterface(); 1476 1477 // FIXME: The receiver could be a reference to a class, meaning that 1478 // we should use the class method. 1479 // id x = [NSObject class]; 1480 // [x performSelector:... withObject:... afterDelay:...]; 1481 Selector S = Msg.getSelector(); 1482 const ObjCMethodDecl *Method = Msg.getDecl(); 1483 if (!Method && ReceiverClass) 1484 Method = ReceiverClass->getInstanceMethod(S); 1485 1486 return getMethodSummary(S, ReceiverClass, Method, Msg.getResultType(), 1487 ObjCMethodSummaries); 1488} 1489 1490const RetainSummary * 1491RetainSummaryManager::getMethodSummary(Selector S, const ObjCInterfaceDecl *ID, 1492 const ObjCMethodDecl *MD, QualType RetTy, 1493 ObjCMethodSummariesTy &CachedSummaries) { 1494 1495 // Look up a summary in our summary cache. 1496 const RetainSummary *Summ = CachedSummaries.find(ID, S); 1497 1498 if (!Summ) { 1499 Summ = getStandardMethodSummary(MD, S, RetTy); 1500 1501 // Annotations override defaults. 1502 updateSummaryFromAnnotations(Summ, MD); 1503 1504 // Memoize the summary. 1505 CachedSummaries[ObjCSummaryKey(ID, S)] = Summ; 1506 } 1507 1508 return Summ; 1509} 1510 1511void RetainSummaryManager::InitializeClassMethodSummaries() { 1512 assert(ScratchArgs.isEmpty()); 1513 // Create the [NSAssertionHandler currentHander] summary. 1514 addClassMethSummary("NSAssertionHandler", "currentHandler", 1515 getPersistentSummary(RetEffect::MakeNotOwned(RetEffect::ObjC))); 1516 1517 // Create the [NSAutoreleasePool addObject:] summary. 1518 ScratchArgs = AF.add(ScratchArgs, 0, Autorelease); 1519 addClassMethSummary("NSAutoreleasePool", "addObject", 1520 getPersistentSummary(RetEffect::MakeNoRet(), 1521 DoNothing, Autorelease)); 1522} 1523 1524void RetainSummaryManager::InitializeMethodSummaries() { 1525 1526 assert (ScratchArgs.isEmpty()); 1527 1528 // Create the "init" selector. It just acts as a pass-through for the 1529 // receiver. 1530 const RetainSummary *InitSumm = getPersistentSummary(ObjCInitRetE, DecRefMsg); 1531 addNSObjectMethSummary(GetNullarySelector("init", Ctx), InitSumm); 1532 1533 // awakeAfterUsingCoder: behaves basically like an 'init' method. It 1534 // claims the receiver and returns a retained object. 1535 addNSObjectMethSummary(GetUnarySelector("awakeAfterUsingCoder", Ctx), 1536 InitSumm); 1537 1538 // The next methods are allocators. 1539 const RetainSummary *AllocSumm = getPersistentSummary(ObjCAllocRetE); 1540 const RetainSummary *CFAllocSumm = 1541 getPersistentSummary(RetEffect::MakeOwned(RetEffect::CF, true)); 1542 1543 // Create the "retain" selector. 1544 RetEffect NoRet = RetEffect::MakeNoRet(); 1545 const RetainSummary *Summ = getPersistentSummary(NoRet, IncRefMsg); 1546 addNSObjectMethSummary(GetNullarySelector("retain", Ctx), Summ); 1547 1548 // Create the "release" selector. 1549 Summ = getPersistentSummary(NoRet, DecRefMsg); 1550 addNSObjectMethSummary(GetNullarySelector("release", Ctx), Summ); 1551 1552 // Create the "drain" selector. 1553 Summ = getPersistentSummary(NoRet, isGCEnabled() ? DoNothing : DecRef); 1554 addNSObjectMethSummary(GetNullarySelector("drain", Ctx), Summ); 1555 1556 // Create the -dealloc summary. 1557 Summ = getPersistentSummary(NoRet, Dealloc); 1558 addNSObjectMethSummary(GetNullarySelector("dealloc", Ctx), Summ); 1559 1560 // Create the "autorelease" selector. 1561 Summ = getPersistentSummary(NoRet, Autorelease); 1562 addNSObjectMethSummary(GetNullarySelector("autorelease", Ctx), Summ); 1563 1564 // Specially handle NSAutoreleasePool. 1565 addInstMethSummary("NSAutoreleasePool", "init", 1566 getPersistentSummary(NoRet, NewAutoreleasePool)); 1567 1568 // For NSWindow, allocated objects are (initially) self-owned. 1569 // FIXME: For now we opt for false negatives with NSWindow, as these objects 1570 // self-own themselves. However, they only do this once they are displayed. 1571 // Thus, we need to track an NSWindow's display status. 1572 // This is tracked in <rdar://problem/6062711>. 1573 // See also http://llvm.org/bugs/show_bug.cgi?id=3714. 1574 const RetainSummary *NoTrackYet = getPersistentSummary(RetEffect::MakeNoRet(), 1575 StopTracking, 1576 StopTracking); 1577 1578 addClassMethSummary("NSWindow", "alloc", NoTrackYet); 1579 1580#if 0 1581 addInstMethSummary("NSWindow", NoTrackYet, "initWithContentRect", 1582 "styleMask", "backing", "defer", NULL); 1583 1584 addInstMethSummary("NSWindow", NoTrackYet, "initWithContentRect", 1585 "styleMask", "backing", "defer", "screen", NULL); 1586#endif 1587 1588 // For NSPanel (which subclasses NSWindow), allocated objects are not 1589 // self-owned. 1590 // FIXME: For now we don't track NSPanels. object for the same reason 1591 // as for NSWindow objects. 1592 addClassMethSummary("NSPanel", "alloc", NoTrackYet); 1593 1594#if 0 1595 addInstMethSummary("NSPanel", NoTrackYet, "initWithContentRect", 1596 "styleMask", "backing", "defer", NULL); 1597 1598 addInstMethSummary("NSPanel", NoTrackYet, "initWithContentRect", 1599 "styleMask", "backing", "defer", "screen", NULL); 1600#endif 1601 1602 // Don't track allocated autorelease pools yet, as it is okay to prematurely 1603 // exit a method. 1604 addClassMethSummary("NSAutoreleasePool", "alloc", NoTrackYet); 1605 addClassMethSummary("NSAutoreleasePool", "allocWithZone", NoTrackYet, false); 1606 1607 // Create summaries QCRenderer/QCView -createSnapShotImageOfType: 1608 addInstMethSummary("QCRenderer", AllocSumm, 1609 "createSnapshotImageOfType", NULL); 1610 addInstMethSummary("QCView", AllocSumm, 1611 "createSnapshotImageOfType", NULL); 1612 1613 // Create summaries for CIContext, 'createCGImage' and 1614 // 'createCGLayerWithSize'. These objects are CF objects, and are not 1615 // automatically garbage collected. 1616 addInstMethSummary("CIContext", CFAllocSumm, 1617 "createCGImage", "fromRect", NULL); 1618 addInstMethSummary("CIContext", CFAllocSumm, 1619 "createCGImage", "fromRect", "format", "colorSpace", NULL); 1620 addInstMethSummary("CIContext", CFAllocSumm, "createCGLayerWithSize", 1621 "info", NULL); 1622} 1623 1624//===----------------------------------------------------------------------===// 1625// AutoreleaseBindings - State used to track objects in autorelease pools. 1626//===----------------------------------------------------------------------===// 1627 1628typedef llvm::ImmutableMap<SymbolRef, unsigned> ARCounts; 1629typedef llvm::ImmutableMap<SymbolRef, ARCounts> ARPoolContents; 1630typedef llvm::ImmutableList<SymbolRef> ARStack; 1631 1632static int AutoRCIndex = 0; 1633static int AutoRBIndex = 0; 1634 1635namespace { class AutoreleasePoolContents {}; } 1636namespace { class AutoreleaseStack {}; } 1637 1638namespace clang { 1639namespace ento { 1640template<> struct ProgramStateTrait<AutoreleaseStack> 1641 : public ProgramStatePartialTrait<ARStack> { 1642 static inline void *GDMIndex() { return &AutoRBIndex; } 1643}; 1644 1645template<> struct ProgramStateTrait<AutoreleasePoolContents> 1646 : public ProgramStatePartialTrait<ARPoolContents> { 1647 static inline void *GDMIndex() { return &AutoRCIndex; } 1648}; 1649} // end GR namespace 1650} // end clang namespace 1651 1652static SymbolRef GetCurrentAutoreleasePool(ProgramStateRef state) { 1653 ARStack stack = state->get<AutoreleaseStack>(); 1654 return stack.isEmpty() ? SymbolRef() : stack.getHead(); 1655} 1656 1657static ProgramStateRef 1658SendAutorelease(ProgramStateRef state, 1659 ARCounts::Factory &F, 1660 SymbolRef sym) { 1661 SymbolRef pool = GetCurrentAutoreleasePool(state); 1662 const ARCounts *cnts = state->get<AutoreleasePoolContents>(pool); 1663 ARCounts newCnts(0); 1664 1665 if (cnts) { 1666 const unsigned *cnt = (*cnts).lookup(sym); 1667 newCnts = F.add(*cnts, sym, cnt ? *cnt + 1 : 1); 1668 } 1669 else 1670 newCnts = F.add(F.getEmptyMap(), sym, 1); 1671 1672 return state->set<AutoreleasePoolContents>(pool, newCnts); 1673} 1674 1675//===----------------------------------------------------------------------===// 1676// Error reporting. 1677//===----------------------------------------------------------------------===// 1678namespace { 1679 typedef llvm::DenseMap<const ExplodedNode *, const RetainSummary *> 1680 SummaryLogTy; 1681 1682 //===-------------===// 1683 // Bug Descriptions. // 1684 //===-------------===// 1685 1686 class CFRefBug : public BugType { 1687 protected: 1688 CFRefBug(StringRef name) 1689 : BugType(name, categories::MemoryCoreFoundationObjectiveC) {} 1690 public: 1691 1692 // FIXME: Eventually remove. 1693 virtual const char *getDescription() const = 0; 1694 1695 virtual bool isLeak() const { return false; } 1696 }; 1697 1698 class UseAfterRelease : public CFRefBug { 1699 public: 1700 UseAfterRelease() : CFRefBug("Use-after-release") {} 1701 1702 const char *getDescription() const { 1703 return "Reference-counted object is used after it is released"; 1704 } 1705 }; 1706 1707 class BadRelease : public CFRefBug { 1708 public: 1709 BadRelease() : CFRefBug("Bad release") {} 1710 1711 const char *getDescription() const { 1712 return "Incorrect decrement of the reference count of an object that is " 1713 "not owned at this point by the caller"; 1714 } 1715 }; 1716 1717 class DeallocGC : public CFRefBug { 1718 public: 1719 DeallocGC() 1720 : CFRefBug("-dealloc called while using garbage collection") {} 1721 1722 const char *getDescription() const { 1723 return "-dealloc called while using garbage collection"; 1724 } 1725 }; 1726 1727 class DeallocNotOwned : public CFRefBug { 1728 public: 1729 DeallocNotOwned() 1730 : CFRefBug("-dealloc sent to non-exclusively owned object") {} 1731 1732 const char *getDescription() const { 1733 return "-dealloc sent to object that may be referenced elsewhere"; 1734 } 1735 }; 1736 1737 class OverAutorelease : public CFRefBug { 1738 public: 1739 OverAutorelease() 1740 : CFRefBug("Object sent -autorelease too many times") {} 1741 1742 const char *getDescription() const { 1743 return "Object sent -autorelease too many times"; 1744 } 1745 }; 1746 1747 class ReturnedNotOwnedForOwned : public CFRefBug { 1748 public: 1749 ReturnedNotOwnedForOwned() 1750 : CFRefBug("Method should return an owned object") {} 1751 1752 const char *getDescription() const { 1753 return "Object with a +0 retain count returned to caller where a +1 " 1754 "(owning) retain count is expected"; 1755 } 1756 }; 1757 1758 class Leak : public CFRefBug { 1759 public: 1760 Leak(StringRef name) 1761 : CFRefBug(name) { 1762 // Leaks should not be reported if they are post-dominated by a sink. 1763 setSuppressOnSink(true); 1764 } 1765 1766 const char *getDescription() const { return ""; } 1767 1768 bool isLeak() const { return true; } 1769 }; 1770 1771 //===---------===// 1772 // Bug Reports. // 1773 //===---------===// 1774 1775 class CFRefReportVisitor : public BugReporterVisitorImpl<CFRefReportVisitor> { 1776 protected: 1777 SymbolRef Sym; 1778 const SummaryLogTy &SummaryLog; 1779 bool GCEnabled; 1780 1781 public: 1782 CFRefReportVisitor(SymbolRef sym, bool gcEnabled, const SummaryLogTy &log) 1783 : Sym(sym), SummaryLog(log), GCEnabled(gcEnabled) {} 1784 1785 virtual void Profile(llvm::FoldingSetNodeID &ID) const { 1786 static int x = 0; 1787 ID.AddPointer(&x); 1788 ID.AddPointer(Sym); 1789 } 1790 1791 virtual PathDiagnosticPiece *VisitNode(const ExplodedNode *N, 1792 const ExplodedNode *PrevN, 1793 BugReporterContext &BRC, 1794 BugReport &BR); 1795 1796 virtual PathDiagnosticPiece *getEndPath(BugReporterContext &BRC, 1797 const ExplodedNode *N, 1798 BugReport &BR); 1799 }; 1800 1801 class CFRefLeakReportVisitor : public CFRefReportVisitor { 1802 public: 1803 CFRefLeakReportVisitor(SymbolRef sym, bool GCEnabled, 1804 const SummaryLogTy &log) 1805 : CFRefReportVisitor(sym, GCEnabled, log) {} 1806 1807 PathDiagnosticPiece *getEndPath(BugReporterContext &BRC, 1808 const ExplodedNode *N, 1809 BugReport &BR); 1810 1811 virtual BugReporterVisitor *clone() const { 1812 // The curiously-recurring template pattern only works for one level of 1813 // subclassing. Rather than make a new template base for 1814 // CFRefReportVisitor, we simply override clone() to do the right thing. 1815 // This could be trouble someday if BugReporterVisitorImpl is ever 1816 // used for something else besides a convenient implementation of clone(). 1817 return new CFRefLeakReportVisitor(*this); 1818 } 1819 }; 1820 1821 class CFRefReport : public BugReport { 1822 void addGCModeDescription(const LangOptions &LOpts, bool GCEnabled); 1823 1824 public: 1825 CFRefReport(CFRefBug &D, const LangOptions &LOpts, bool GCEnabled, 1826 const SummaryLogTy &Log, ExplodedNode *n, SymbolRef sym, 1827 bool registerVisitor = true) 1828 : BugReport(D, D.getDescription(), n) { 1829 if (registerVisitor) 1830 addVisitor(new CFRefReportVisitor(sym, GCEnabled, Log)); 1831 addGCModeDescription(LOpts, GCEnabled); 1832 } 1833 1834 CFRefReport(CFRefBug &D, const LangOptions &LOpts, bool GCEnabled, 1835 const SummaryLogTy &Log, ExplodedNode *n, SymbolRef sym, 1836 StringRef endText) 1837 : BugReport(D, D.getDescription(), endText, n) { 1838 addVisitor(new CFRefReportVisitor(sym, GCEnabled, Log)); 1839 addGCModeDescription(LOpts, GCEnabled); 1840 } 1841 1842 virtual std::pair<ranges_iterator, ranges_iterator> getRanges() { 1843 const CFRefBug& BugTy = static_cast<CFRefBug&>(getBugType()); 1844 if (!BugTy.isLeak()) 1845 return BugReport::getRanges(); 1846 else 1847 return std::make_pair(ranges_iterator(), ranges_iterator()); 1848 } 1849 }; 1850 1851 class CFRefLeakReport : public CFRefReport { 1852 const MemRegion* AllocBinding; 1853 1854 public: 1855 CFRefLeakReport(CFRefBug &D, const LangOptions &LOpts, bool GCEnabled, 1856 const SummaryLogTy &Log, ExplodedNode *n, SymbolRef sym, 1857 CheckerContext &Ctx); 1858 1859 PathDiagnosticLocation getLocation(const SourceManager &SM) const { 1860 assert(Location.isValid()); 1861 return Location; 1862 } 1863 }; 1864} // end anonymous namespace 1865 1866void CFRefReport::addGCModeDescription(const LangOptions &LOpts, 1867 bool GCEnabled) { 1868 const char *GCModeDescription = 0; 1869 1870 switch (LOpts.getGC()) { 1871 case LangOptions::GCOnly: 1872 assert(GCEnabled); 1873 GCModeDescription = "Code is compiled to only use garbage collection"; 1874 break; 1875 1876 case LangOptions::NonGC: 1877 assert(!GCEnabled); 1878 GCModeDescription = "Code is compiled to use reference counts"; 1879 break; 1880 1881 case LangOptions::HybridGC: 1882 if (GCEnabled) { 1883 GCModeDescription = "Code is compiled to use either garbage collection " 1884 "(GC) or reference counts (non-GC). The bug occurs " 1885 "with GC enabled"; 1886 break; 1887 } else { 1888 GCModeDescription = "Code is compiled to use either garbage collection " 1889 "(GC) or reference counts (non-GC). The bug occurs " 1890 "in non-GC mode"; 1891 break; 1892 } 1893 } 1894 1895 assert(GCModeDescription && "invalid/unknown GC mode"); 1896 addExtraText(GCModeDescription); 1897} 1898 1899// FIXME: This should be a method on SmallVector. 1900static inline bool contains(const SmallVectorImpl<ArgEffect>& V, 1901 ArgEffect X) { 1902 for (SmallVectorImpl<ArgEffect>::const_iterator I=V.begin(), E=V.end(); 1903 I!=E; ++I) 1904 if (*I == X) return true; 1905 1906 return false; 1907} 1908 1909static bool isNumericLiteralExpression(const Expr *E) { 1910 // FIXME: This set of cases was copied from SemaExprObjC. 1911 return isa<IntegerLiteral>(E) || 1912 isa<CharacterLiteral>(E) || 1913 isa<FloatingLiteral>(E) || 1914 isa<ObjCBoolLiteralExpr>(E) || 1915 isa<CXXBoolLiteralExpr>(E); 1916} 1917 1918PathDiagnosticPiece *CFRefReportVisitor::VisitNode(const ExplodedNode *N, 1919 const ExplodedNode *PrevN, 1920 BugReporterContext &BRC, 1921 BugReport &BR) { 1922 // FIXME: We will eventually need to handle non-statement-based events 1923 // (__attribute__((cleanup))). 1924 if (!isa<StmtPoint>(N->getLocation())) 1925 return NULL; 1926 1927 // Check if the type state has changed. 1928 ProgramStateRef PrevSt = PrevN->getState(); 1929 ProgramStateRef CurrSt = N->getState(); 1930 const LocationContext *LCtx = N->getLocationContext(); 1931 1932 const RefVal* CurrT = CurrSt->get<RefBindings>(Sym); 1933 if (!CurrT) return NULL; 1934 1935 const RefVal &CurrV = *CurrT; 1936 const RefVal *PrevT = PrevSt->get<RefBindings>(Sym); 1937 1938 // Create a string buffer to constain all the useful things we want 1939 // to tell the user. 1940 std::string sbuf; 1941 llvm::raw_string_ostream os(sbuf); 1942 1943 // This is the allocation site since the previous node had no bindings 1944 // for this symbol. 1945 if (!PrevT) { 1946 const Stmt *S = cast<StmtPoint>(N->getLocation()).getStmt(); 1947 1948 if (isa<ObjCArrayLiteral>(S)) { 1949 os << "NSArray literal is an object with a +0 retain count"; 1950 } 1951 else if (isa<ObjCDictionaryLiteral>(S)) { 1952 os << "NSDictionary literal is an object with a +0 retain count"; 1953 } 1954 else if (const ObjCBoxedExpr *BL = dyn_cast<ObjCBoxedExpr>(S)) { 1955 if (isNumericLiteralExpression(BL->getSubExpr())) 1956 os << "NSNumber literal is an object with a +0 retain count"; 1957 else { 1958 const ObjCInterfaceDecl *BoxClass = 0; 1959 if (const ObjCMethodDecl *Method = BL->getBoxingMethod()) 1960 BoxClass = Method->getClassInterface(); 1961 1962 // We should always be able to find the boxing class interface, 1963 // but consider this future-proofing. 1964 if (BoxClass) 1965 os << *BoxClass << " b"; 1966 else 1967 os << "B"; 1968 1969 os << "oxed expression produces an object with a +0 retain count"; 1970 } 1971 } 1972 else { 1973 if (const CallExpr *CE = dyn_cast<CallExpr>(S)) { 1974 // Get the name of the callee (if it is available). 1975 SVal X = CurrSt->getSValAsScalarOrLoc(CE->getCallee(), LCtx); 1976 if (const FunctionDecl *FD = X.getAsFunctionDecl()) 1977 os << "Call to function '" << *FD << '\''; 1978 else 1979 os << "function call"; 1980 } 1981 else { 1982 assert(isa<ObjCMessageExpr>(S)); 1983 CallEventManager &Mgr = CurrSt->getStateManager().getCallEventManager(); 1984 CallEventRef<ObjCMethodCall> Call 1985 = Mgr.getObjCMethodCall(cast<ObjCMessageExpr>(S), CurrSt, LCtx); 1986 1987 switch (Call->getMessageKind()) { 1988 case OCM_Message: 1989 os << "Method"; 1990 break; 1991 case OCM_PropertyAccess: 1992 os << "Property"; 1993 break; 1994 case OCM_Subscript: 1995 os << "Subscript"; 1996 break; 1997 } 1998 } 1999 2000 if (CurrV.getObjKind() == RetEffect::CF) { 2001 os << " returns a Core Foundation object with a "; 2002 } 2003 else { 2004 assert (CurrV.getObjKind() == RetEffect::ObjC); 2005 os << " returns an Objective-C object with a "; 2006 } 2007 2008 if (CurrV.isOwned()) { 2009 os << "+1 retain count"; 2010 2011 if (GCEnabled) { 2012 assert(CurrV.getObjKind() == RetEffect::CF); 2013 os << ". " 2014 "Core Foundation objects are not automatically garbage collected."; 2015 } 2016 } 2017 else { 2018 assert (CurrV.isNotOwned()); 2019 os << "+0 retain count"; 2020 } 2021 } 2022 2023 PathDiagnosticLocation Pos(S, BRC.getSourceManager(), 2024 N->getLocationContext()); 2025 return new PathDiagnosticEventPiece(Pos, os.str()); 2026 } 2027 2028 // Gather up the effects that were performed on the object at this 2029 // program point 2030 SmallVector<ArgEffect, 2> AEffects; 2031 2032 const ExplodedNode *OrigNode = BRC.getNodeResolver().getOriginalNode(N); 2033 if (const RetainSummary *Summ = SummaryLog.lookup(OrigNode)) { 2034 // We only have summaries attached to nodes after evaluating CallExpr and 2035 // ObjCMessageExprs. 2036 const Stmt *S = cast<StmtPoint>(N->getLocation()).getStmt(); 2037 2038 if (const CallExpr *CE = dyn_cast<CallExpr>(S)) { 2039 // Iterate through the parameter expressions and see if the symbol 2040 // was ever passed as an argument. 2041 unsigned i = 0; 2042 2043 for (CallExpr::const_arg_iterator AI=CE->arg_begin(), AE=CE->arg_end(); 2044 AI!=AE; ++AI, ++i) { 2045 2046 // Retrieve the value of the argument. Is it the symbol 2047 // we are interested in? 2048 if (CurrSt->getSValAsScalarOrLoc(*AI, LCtx).getAsLocSymbol() != Sym) 2049 continue; 2050 2051 // We have an argument. Get the effect! 2052 AEffects.push_back(Summ->getArg(i)); 2053 } 2054 } 2055 else if (const ObjCMessageExpr *ME = dyn_cast<ObjCMessageExpr>(S)) { 2056 if (const Expr *receiver = ME->getInstanceReceiver()) 2057 if (CurrSt->getSValAsScalarOrLoc(receiver, LCtx) 2058 .getAsLocSymbol() == Sym) { 2059 // The symbol we are tracking is the receiver. 2060 AEffects.push_back(Summ->getReceiverEffect()); 2061 } 2062 } 2063 } 2064 2065 do { 2066 // Get the previous type state. 2067 RefVal PrevV = *PrevT; 2068 2069 // Specially handle -dealloc. 2070 if (!GCEnabled && contains(AEffects, Dealloc)) { 2071 // Determine if the object's reference count was pushed to zero. 2072 assert(!(PrevV == CurrV) && "The typestate *must* have changed."); 2073 // We may not have transitioned to 'release' if we hit an error. 2074 // This case is handled elsewhere. 2075 if (CurrV.getKind() == RefVal::Released) { 2076 assert(CurrV.getCombinedCounts() == 0); 2077 os << "Object released by directly sending the '-dealloc' message"; 2078 break; 2079 } 2080 } 2081 2082 // Specially handle CFMakeCollectable and friends. 2083 if (contains(AEffects, MakeCollectable)) { 2084 // Get the name of the function. 2085 const Stmt *S = cast<StmtPoint>(N->getLocation()).getStmt(); 2086 SVal X = 2087 CurrSt->getSValAsScalarOrLoc(cast<CallExpr>(S)->getCallee(), LCtx); 2088 const FunctionDecl *FD = X.getAsFunctionDecl(); 2089 2090 if (GCEnabled) { 2091 // Determine if the object's reference count was pushed to zero. 2092 assert(!(PrevV == CurrV) && "The typestate *must* have changed."); 2093 2094 os << "In GC mode a call to '" << *FD 2095 << "' decrements an object's retain count and registers the " 2096 "object with the garbage collector. "; 2097 2098 if (CurrV.getKind() == RefVal::Released) { 2099 assert(CurrV.getCount() == 0); 2100 os << "Since it now has a 0 retain count the object can be " 2101 "automatically collected by the garbage collector."; 2102 } 2103 else 2104 os << "An object must have a 0 retain count to be garbage collected. " 2105 "After this call its retain count is +" << CurrV.getCount() 2106 << '.'; 2107 } 2108 else 2109 os << "When GC is not enabled a call to '" << *FD 2110 << "' has no effect on its argument."; 2111 2112 // Nothing more to say. 2113 break; 2114 } 2115 2116 // Determine if the typestate has changed. 2117 if (!(PrevV == CurrV)) 2118 switch (CurrV.getKind()) { 2119 case RefVal::Owned: 2120 case RefVal::NotOwned: 2121 2122 if (PrevV.getCount() == CurrV.getCount()) { 2123 // Did an autorelease message get sent? 2124 if (PrevV.getAutoreleaseCount() == CurrV.getAutoreleaseCount()) 2125 return 0; 2126 2127 assert(PrevV.getAutoreleaseCount() < CurrV.getAutoreleaseCount()); 2128 os << "Object sent -autorelease message"; 2129 break; 2130 } 2131 2132 if (PrevV.getCount() > CurrV.getCount()) 2133 os << "Reference count decremented."; 2134 else 2135 os << "Reference count incremented."; 2136 2137 if (unsigned Count = CurrV.getCount()) 2138 os << " The object now has a +" << Count << " retain count."; 2139 2140 if (PrevV.getKind() == RefVal::Released) { 2141 assert(GCEnabled && CurrV.getCount() > 0); 2142 os << " The object is not eligible for garbage collection until " 2143 "the retain count reaches 0 again."; 2144 } 2145 2146 break; 2147 2148 case RefVal::Released: 2149 os << "Object released."; 2150 break; 2151 2152 case RefVal::ReturnedOwned: 2153 // Autoreleases can be applied after marking a node ReturnedOwned. 2154 if (CurrV.getAutoreleaseCount()) 2155 return NULL; 2156 2157 os << "Object returned to caller as an owning reference (single " 2158 "retain count transferred to caller)"; 2159 break; 2160 2161 case RefVal::ReturnedNotOwned: 2162 os << "Object returned to caller with a +0 retain count"; 2163 break; 2164 2165 default: 2166 return NULL; 2167 } 2168 2169 // Emit any remaining diagnostics for the argument effects (if any). 2170 for (SmallVectorImpl<ArgEffect>::iterator I=AEffects.begin(), 2171 E=AEffects.end(); I != E; ++I) { 2172 2173 // A bunch of things have alternate behavior under GC. 2174 if (GCEnabled) 2175 switch (*I) { 2176 default: break; 2177 case Autorelease: 2178 os << "In GC mode an 'autorelease' has no effect."; 2179 continue; 2180 case IncRefMsg: 2181 os << "In GC mode the 'retain' message has no effect."; 2182 continue; 2183 case DecRefMsg: 2184 os << "In GC mode the 'release' message has no effect."; 2185 continue; 2186 } 2187 } 2188 } while (0); 2189 2190 if (os.str().empty()) 2191 return 0; // We have nothing to say! 2192 2193 const Stmt *S = cast<StmtPoint>(N->getLocation()).getStmt(); 2194 PathDiagnosticLocation Pos(S, BRC.getSourceManager(), 2195 N->getLocationContext()); 2196 PathDiagnosticPiece *P = new PathDiagnosticEventPiece(Pos, os.str()); 2197 2198 // Add the range by scanning the children of the statement for any bindings 2199 // to Sym. 2200 for (Stmt::const_child_iterator I = S->child_begin(), E = S->child_end(); 2201 I!=E; ++I) 2202 if (const Expr *Exp = dyn_cast_or_null<Expr>(*I)) 2203 if (CurrSt->getSValAsScalarOrLoc(Exp, LCtx).getAsLocSymbol() == Sym) { 2204 P->addRange(Exp->getSourceRange()); 2205 break; 2206 } 2207 2208 return P; 2209} 2210 2211// Find the first node in the current function context that referred to the 2212// tracked symbol and the memory location that value was stored to. Note, the 2213// value is only reported if the allocation occurred in the same function as 2214// the leak. 2215static std::pair<const ExplodedNode*,const MemRegion*> 2216GetAllocationSite(ProgramStateManager& StateMgr, const ExplodedNode *N, 2217 SymbolRef Sym) { 2218 const ExplodedNode *Last = N; 2219 const MemRegion* FirstBinding = 0; 2220 const LocationContext *LeakContext = N->getLocationContext(); 2221 2222 while (N) { 2223 ProgramStateRef St = N->getState(); 2224 RefBindings B = St->get<RefBindings>(); 2225 2226 if (!B.lookup(Sym)) 2227 break; 2228 2229 StoreManager::FindUniqueBinding FB(Sym); 2230 StateMgr.iterBindings(St, FB); 2231 if (FB) FirstBinding = FB.getRegion(); 2232 2233 // Allocation node, is the last node in the current context in which the 2234 // symbol was tracked. 2235 if (N->getLocationContext() == LeakContext) 2236 Last = N; 2237 2238 N = N->pred_empty() ? NULL : *(N->pred_begin()); 2239 } 2240 2241 // If allocation happened in a function different from the leak node context, 2242 // do not report the binding. 2243 if (N->getLocationContext() != LeakContext) { 2244 FirstBinding = 0; 2245 } 2246 2247 return std::make_pair(Last, FirstBinding); 2248} 2249 2250PathDiagnosticPiece* 2251CFRefReportVisitor::getEndPath(BugReporterContext &BRC, 2252 const ExplodedNode *EndN, 2253 BugReport &BR) { 2254 BR.markInteresting(Sym); 2255 return BugReporterVisitor::getDefaultEndPath(BRC, EndN, BR); 2256} 2257 2258PathDiagnosticPiece* 2259CFRefLeakReportVisitor::getEndPath(BugReporterContext &BRC, 2260 const ExplodedNode *EndN, 2261 BugReport &BR) { 2262 2263 // Tell the BugReporterContext to report cases when the tracked symbol is 2264 // assigned to different variables, etc. 2265 BR.markInteresting(Sym); 2266 2267 // We are reporting a leak. Walk up the graph to get to the first node where 2268 // the symbol appeared, and also get the first VarDecl that tracked object 2269 // is stored to. 2270 const ExplodedNode *AllocNode = 0; 2271 const MemRegion* FirstBinding = 0; 2272 2273 llvm::tie(AllocNode, FirstBinding) = 2274 GetAllocationSite(BRC.getStateManager(), EndN, Sym); 2275 2276 SourceManager& SM = BRC.getSourceManager(); 2277 2278 // Compute an actual location for the leak. Sometimes a leak doesn't 2279 // occur at an actual statement (e.g., transition between blocks; end 2280 // of function) so we need to walk the graph and compute a real location. 2281 const ExplodedNode *LeakN = EndN; 2282 PathDiagnosticLocation L = PathDiagnosticLocation::createEndOfPath(LeakN, SM); 2283 2284 std::string sbuf; 2285 llvm::raw_string_ostream os(sbuf); 2286 2287 os << "Object leaked: "; 2288 2289 if (FirstBinding) { 2290 os << "object allocated and stored into '" 2291 << FirstBinding->getString() << '\''; 2292 } 2293 else 2294 os << "allocated object"; 2295 2296 // Get the retain count. 2297 const RefVal* RV = EndN->getState()->get<RefBindings>(Sym); 2298 2299 if (RV->getKind() == RefVal::ErrorLeakReturned) { 2300 // FIXME: Per comments in rdar://6320065, "create" only applies to CF 2301 // objects. Only "copy", "alloc", "retain" and "new" transfer ownership 2302 // to the caller for NS objects. 2303 const Decl *D = &EndN->getCodeDecl(); 2304 if (const ObjCMethodDecl *MD = dyn_cast<ObjCMethodDecl>(D)) { 2305 os << " is returned from a method whose name ('" 2306 << MD->getSelector().getAsString() 2307 << "') does not start with 'copy', 'mutableCopy', 'alloc' or 'new'." 2308 " This violates the naming convention rules" 2309 " given in the Memory Management Guide for Cocoa"; 2310 } 2311 else { 2312 const FunctionDecl *FD = cast<FunctionDecl>(D); 2313 os << " is returned from a function whose name ('" 2314 << *FD 2315 << "') does not contain 'Copy' or 'Create'. This violates the naming" 2316 " convention rules given in the Memory Management Guide for Core" 2317 " Foundation"; 2318 } 2319 } 2320 else if (RV->getKind() == RefVal::ErrorGCLeakReturned) { 2321 ObjCMethodDecl &MD = cast<ObjCMethodDecl>(EndN->getCodeDecl()); 2322 os << " and returned from method '" << MD.getSelector().getAsString() 2323 << "' is potentially leaked when using garbage collection. Callers " 2324 "of this method do not expect a returned object with a +1 retain " 2325 "count since they expect the object to be managed by the garbage " 2326 "collector"; 2327 } 2328 else 2329 os << " is not referenced later in this execution path and has a retain " 2330 "count of +" << RV->getCount(); 2331 2332 return new PathDiagnosticEventPiece(L, os.str()); 2333} 2334 2335CFRefLeakReport::CFRefLeakReport(CFRefBug &D, const LangOptions &LOpts, 2336 bool GCEnabled, const SummaryLogTy &Log, 2337 ExplodedNode *n, SymbolRef sym, 2338 CheckerContext &Ctx) 2339: CFRefReport(D, LOpts, GCEnabled, Log, n, sym, false) { 2340 2341 // Most bug reports are cached at the location where they occurred. 2342 // With leaks, we want to unique them by the location where they were 2343 // allocated, and only report a single path. To do this, we need to find 2344 // the allocation site of a piece of tracked memory, which we do via a 2345 // call to GetAllocationSite. This will walk the ExplodedGraph backwards. 2346 // Note that this is *not* the trimmed graph; we are guaranteed, however, 2347 // that all ancestor nodes that represent the allocation site have the 2348 // same SourceLocation. 2349 const ExplodedNode *AllocNode = 0; 2350 2351 const SourceManager& SMgr = Ctx.getSourceManager(); 2352 2353 llvm::tie(AllocNode, AllocBinding) = // Set AllocBinding. 2354 GetAllocationSite(Ctx.getStateManager(), getErrorNode(), sym); 2355 2356 // Get the SourceLocation for the allocation site. 2357 // FIXME: This will crash the analyzer if an allocation comes from an 2358 // implicit call. (Currently there are no such allocations in Cocoa, though.) 2359 const Stmt *AllocStmt; 2360 ProgramPoint P = AllocNode->getLocation(); 2361 if (CallExitEnd *Exit = dyn_cast<CallExitEnd>(&P)) 2362 AllocStmt = Exit->getCalleeContext()->getCallSite(); 2363 else 2364 AllocStmt = cast<PostStmt>(P).getStmt(); 2365 assert(AllocStmt && "All allocations must come from explicit calls"); 2366 Location = PathDiagnosticLocation::createBegin(AllocStmt, SMgr, 2367 n->getLocationContext()); 2368 // Fill in the description of the bug. 2369 Description.clear(); 2370 llvm::raw_string_ostream os(Description); 2371 os << "Potential leak "; 2372 if (GCEnabled) 2373 os << "(when using garbage collection) "; 2374 os << "of an object"; 2375 2376 // FIXME: AllocBinding doesn't get populated for RegionStore yet. 2377 if (AllocBinding) 2378 os << " stored into '" << AllocBinding->getString() << '\''; 2379 2380 addVisitor(new CFRefLeakReportVisitor(sym, GCEnabled, Log)); 2381} 2382 2383//===----------------------------------------------------------------------===// 2384// Main checker logic. 2385//===----------------------------------------------------------------------===// 2386 2387namespace { 2388class RetainCountChecker 2389 : public Checker< check::Bind, 2390 check::DeadSymbols, 2391 check::EndAnalysis, 2392 check::EndPath, 2393 check::PostStmt<BlockExpr>, 2394 check::PostStmt<CastExpr>, 2395 check::PostStmt<ObjCArrayLiteral>, 2396 check::PostStmt<ObjCDictionaryLiteral>, 2397 check::PostStmt<ObjCBoxedExpr>, 2398 check::PostCall, 2399 check::PreStmt<ReturnStmt>, 2400 check::RegionChanges, 2401 eval::Assume, 2402 eval::Call > { 2403 mutable OwningPtr<CFRefBug> useAfterRelease, releaseNotOwned; 2404 mutable OwningPtr<CFRefBug> deallocGC, deallocNotOwned; 2405 mutable OwningPtr<CFRefBug> overAutorelease, returnNotOwnedForOwned; 2406 mutable OwningPtr<CFRefBug> leakWithinFunction, leakAtReturn; 2407 mutable OwningPtr<CFRefBug> leakWithinFunctionGC, leakAtReturnGC; 2408 2409 typedef llvm::DenseMap<SymbolRef, const SimpleProgramPointTag *> SymbolTagMap; 2410 2411 // This map is only used to ensure proper deletion of any allocated tags. 2412 mutable SymbolTagMap DeadSymbolTags; 2413 2414 mutable OwningPtr<RetainSummaryManager> Summaries; 2415 mutable OwningPtr<RetainSummaryManager> SummariesGC; 2416 2417 mutable ARCounts::Factory ARCountFactory; 2418 2419 mutable SummaryLogTy SummaryLog; 2420 mutable bool ShouldResetSummaryLog; 2421 2422public: 2423 RetainCountChecker() : ShouldResetSummaryLog(false) {} 2424 2425 virtual ~RetainCountChecker() { 2426 DeleteContainerSeconds(DeadSymbolTags); 2427 } 2428 2429 void checkEndAnalysis(ExplodedGraph &G, BugReporter &BR, 2430 ExprEngine &Eng) const { 2431 // FIXME: This is a hack to make sure the summary log gets cleared between 2432 // analyses of different code bodies. 2433 // 2434 // Why is this necessary? Because a checker's lifetime is tied to a 2435 // translation unit, but an ExplodedGraph's lifetime is just a code body. 2436 // Once in a blue moon, a new ExplodedNode will have the same address as an 2437 // old one with an associated summary, and the bug report visitor gets very 2438 // confused. (To make things worse, the summary lifetime is currently also 2439 // tied to a code body, so we get a crash instead of incorrect results.) 2440 // 2441 // Why is this a bad solution? Because if the lifetime of the ExplodedGraph 2442 // changes, things will start going wrong again. Really the lifetime of this 2443 // log needs to be tied to either the specific nodes in it or the entire 2444 // ExplodedGraph, not to a specific part of the code being analyzed. 2445 // 2446 // (Also, having stateful local data means that the same checker can't be 2447 // used from multiple threads, but a lot of checkers have incorrect 2448 // assumptions about that anyway. So that wasn't a priority at the time of 2449 // this fix.) 2450 // 2451 // This happens at the end of analysis, but bug reports are emitted /after/ 2452 // this point. So we can't just clear the summary log now. Instead, we mark 2453 // that the next time we access the summary log, it should be cleared. 2454 2455 // If we never reset the summary log during /this/ code body analysis, 2456 // there were no new summaries. There might still have been summaries from 2457 // the /last/ analysis, so clear them out to make sure the bug report 2458 // visitors don't get confused. 2459 if (ShouldResetSummaryLog) 2460 SummaryLog.clear(); 2461 2462 ShouldResetSummaryLog = !SummaryLog.empty(); 2463 } 2464 2465 CFRefBug *getLeakWithinFunctionBug(const LangOptions &LOpts, 2466 bool GCEnabled) const { 2467 if (GCEnabled) { 2468 if (!leakWithinFunctionGC) 2469 leakWithinFunctionGC.reset(new Leak("Leak of object when using " 2470 "garbage collection")); 2471 return leakWithinFunctionGC.get(); 2472 } else { 2473 if (!leakWithinFunction) { 2474 if (LOpts.getGC() == LangOptions::HybridGC) { 2475 leakWithinFunction.reset(new Leak("Leak of object when not using " 2476 "garbage collection (GC) in " 2477 "dual GC/non-GC code")); 2478 } else { 2479 leakWithinFunction.reset(new Leak("Leak")); 2480 } 2481 } 2482 return leakWithinFunction.get(); 2483 } 2484 } 2485 2486 CFRefBug *getLeakAtReturnBug(const LangOptions &LOpts, bool GCEnabled) const { 2487 if (GCEnabled) { 2488 if (!leakAtReturnGC) 2489 leakAtReturnGC.reset(new Leak("Leak of returned object when using " 2490 "garbage collection")); 2491 return leakAtReturnGC.get(); 2492 } else { 2493 if (!leakAtReturn) { 2494 if (LOpts.getGC() == LangOptions::HybridGC) { 2495 leakAtReturn.reset(new Leak("Leak of returned object when not using " 2496 "garbage collection (GC) in dual " 2497 "GC/non-GC code")); 2498 } else { 2499 leakAtReturn.reset(new Leak("Leak of returned object")); 2500 } 2501 } 2502 return leakAtReturn.get(); 2503 } 2504 } 2505 2506 RetainSummaryManager &getSummaryManager(ASTContext &Ctx, 2507 bool GCEnabled) const { 2508 // FIXME: We don't support ARC being turned on and off during one analysis. 2509 // (nor, for that matter, do we support changing ASTContexts) 2510 bool ARCEnabled = (bool)Ctx.getLangOpts().ObjCAutoRefCount; 2511 if (GCEnabled) { 2512 if (!SummariesGC) 2513 SummariesGC.reset(new RetainSummaryManager(Ctx, true, ARCEnabled)); 2514 else 2515 assert(SummariesGC->isARCEnabled() == ARCEnabled); 2516 return *SummariesGC; 2517 } else { 2518 if (!Summaries) 2519 Summaries.reset(new RetainSummaryManager(Ctx, false, ARCEnabled)); 2520 else 2521 assert(Summaries->isARCEnabled() == ARCEnabled); 2522 return *Summaries; 2523 } 2524 } 2525 2526 RetainSummaryManager &getSummaryManager(CheckerContext &C) const { 2527 return getSummaryManager(C.getASTContext(), C.isObjCGCEnabled()); 2528 } 2529 2530 void printState(raw_ostream &Out, ProgramStateRef State, 2531 const char *NL, const char *Sep) const; 2532 2533 void checkBind(SVal loc, SVal val, const Stmt *S, CheckerContext &C) const; 2534 void checkPostStmt(const BlockExpr *BE, CheckerContext &C) const; 2535 void checkPostStmt(const CastExpr *CE, CheckerContext &C) const; 2536 2537 void checkPostStmt(const ObjCArrayLiteral *AL, CheckerContext &C) const; 2538 void checkPostStmt(const ObjCDictionaryLiteral *DL, CheckerContext &C) const; 2539 void checkPostStmt(const ObjCBoxedExpr *BE, CheckerContext &C) const; 2540 2541 void checkPostCall(const CallEvent &Call, CheckerContext &C) const; 2542 2543 void checkSummary(const RetainSummary &Summ, const CallEvent &Call, 2544 CheckerContext &C) const; 2545 2546 bool evalCall(const CallExpr *CE, CheckerContext &C) const; 2547 2548 ProgramStateRef evalAssume(ProgramStateRef state, SVal Cond, 2549 bool Assumption) const; 2550 2551 ProgramStateRef 2552 checkRegionChanges(ProgramStateRef state, 2553 const StoreManager::InvalidatedSymbols *invalidated, 2554 ArrayRef<const MemRegion *> ExplicitRegions, 2555 ArrayRef<const MemRegion *> Regions, 2556 const CallEvent *Call) const; 2557 2558 bool wantsRegionChangeUpdate(ProgramStateRef state) const { 2559 return true; 2560 } 2561 2562 void checkPreStmt(const ReturnStmt *S, CheckerContext &C) const; 2563 void checkReturnWithRetEffect(const ReturnStmt *S, CheckerContext &C, 2564 ExplodedNode *Pred, RetEffect RE, RefVal X, 2565 SymbolRef Sym, ProgramStateRef state) const; 2566 2567 void checkDeadSymbols(SymbolReaper &SymReaper, CheckerContext &C) const; 2568 void checkEndPath(CheckerContext &C) const; 2569 2570 ProgramStateRef updateSymbol(ProgramStateRef state, SymbolRef sym, 2571 RefVal V, ArgEffect E, RefVal::Kind &hasErr, 2572 CheckerContext &C) const; 2573 2574 void processNonLeakError(ProgramStateRef St, SourceRange ErrorRange, 2575 RefVal::Kind ErrorKind, SymbolRef Sym, 2576 CheckerContext &C) const; 2577 2578 void processObjCLiterals(CheckerContext &C, const Expr *Ex) const; 2579 2580 const ProgramPointTag *getDeadSymbolTag(SymbolRef sym) const; 2581 2582 ProgramStateRef handleSymbolDeath(ProgramStateRef state, 2583 SymbolRef sid, RefVal V, 2584 SmallVectorImpl<SymbolRef> &Leaked) const; 2585 2586 std::pair<ExplodedNode *, ProgramStateRef > 2587 handleAutoreleaseCounts(ProgramStateRef state, 2588 GenericNodeBuilderRefCount Bd, ExplodedNode *Pred, 2589 CheckerContext &Ctx, SymbolRef Sym, RefVal V) const; 2590 2591 ExplodedNode *processLeaks(ProgramStateRef state, 2592 SmallVectorImpl<SymbolRef> &Leaked, 2593 GenericNodeBuilderRefCount &Builder, 2594 CheckerContext &Ctx, 2595 ExplodedNode *Pred = 0) const; 2596}; 2597} // end anonymous namespace 2598 2599namespace { 2600class StopTrackingCallback : public SymbolVisitor { 2601 ProgramStateRef state; 2602public: 2603 StopTrackingCallback(ProgramStateRef st) : state(st) {} 2604 ProgramStateRef getState() const { return state; } 2605 2606 bool VisitSymbol(SymbolRef sym) { 2607 state = state->remove<RefBindings>(sym); 2608 return true; 2609 } 2610}; 2611} // end anonymous namespace 2612 2613//===----------------------------------------------------------------------===// 2614// Handle statements that may have an effect on refcounts. 2615//===----------------------------------------------------------------------===// 2616 2617void RetainCountChecker::checkPostStmt(const BlockExpr *BE, 2618 CheckerContext &C) const { 2619 2620 // Scan the BlockDecRefExprs for any object the retain count checker 2621 // may be tracking. 2622 if (!BE->getBlockDecl()->hasCaptures()) 2623 return; 2624 2625 ProgramStateRef state = C.getState(); 2626 const BlockDataRegion *R = 2627 cast<BlockDataRegion>(state->getSVal(BE, 2628 C.getLocationContext()).getAsRegion()); 2629 2630 BlockDataRegion::referenced_vars_iterator I = R->referenced_vars_begin(), 2631 E = R->referenced_vars_end(); 2632 2633 if (I == E) 2634 return; 2635 2636 // FIXME: For now we invalidate the tracking of all symbols passed to blocks 2637 // via captured variables, even though captured variables result in a copy 2638 // and in implicit increment/decrement of a retain count. 2639 SmallVector<const MemRegion*, 10> Regions; 2640 const LocationContext *LC = C.getLocationContext(); 2641 MemRegionManager &MemMgr = C.getSValBuilder().getRegionManager(); 2642 2643 for ( ; I != E; ++I) { 2644 const VarRegion *VR = *I; 2645 if (VR->getSuperRegion() == R) { 2646 VR = MemMgr.getVarRegion(VR->getDecl(), LC); 2647 } 2648 Regions.push_back(VR); 2649 } 2650 2651 state = 2652 state->scanReachableSymbols<StopTrackingCallback>(Regions.data(), 2653 Regions.data() + Regions.size()).getState(); 2654 C.addTransition(state); 2655} 2656 2657void RetainCountChecker::checkPostStmt(const CastExpr *CE, 2658 CheckerContext &C) const { 2659 const ObjCBridgedCastExpr *BE = dyn_cast<ObjCBridgedCastExpr>(CE); 2660 if (!BE) 2661 return; 2662 2663 ArgEffect AE = IncRef; 2664 2665 switch (BE->getBridgeKind()) { 2666 case clang::OBC_Bridge: 2667 // Do nothing. 2668 return; 2669 case clang::OBC_BridgeRetained: 2670 AE = IncRef; 2671 break; 2672 case clang::OBC_BridgeTransfer: 2673 AE = DecRefBridgedTransfered; 2674 break; 2675 } 2676 2677 ProgramStateRef state = C.getState(); 2678 SymbolRef Sym = state->getSVal(CE, C.getLocationContext()).getAsLocSymbol(); 2679 if (!Sym) 2680 return; 2681 const RefVal* T = state->get<RefBindings>(Sym); 2682 if (!T) 2683 return; 2684 2685 RefVal::Kind hasErr = (RefVal::Kind) 0; 2686 state = updateSymbol(state, Sym, *T, AE, hasErr, C); 2687 2688 if (hasErr) { 2689 // FIXME: If we get an error during a bridge cast, should we report it? 2690 // Should we assert that there is no error? 2691 return; 2692 } 2693 2694 C.addTransition(state); 2695} 2696 2697void RetainCountChecker::processObjCLiterals(CheckerContext &C, 2698 const Expr *Ex) const { 2699 ProgramStateRef state = C.getState(); 2700 const ExplodedNode *pred = C.getPredecessor(); 2701 for (Stmt::const_child_iterator it = Ex->child_begin(), et = Ex->child_end() ; 2702 it != et ; ++it) { 2703 const Stmt *child = *it; 2704 SVal V = state->getSVal(child, pred->getLocationContext()); 2705 if (SymbolRef sym = V.getAsSymbol()) 2706 if (const RefVal* T = state->get<RefBindings>(sym)) { 2707 RefVal::Kind hasErr = (RefVal::Kind) 0; 2708 state = updateSymbol(state, sym, *T, MayEscape, hasErr, C); 2709 if (hasErr) { 2710 processNonLeakError(state, child->getSourceRange(), hasErr, sym, C); 2711 return; 2712 } 2713 } 2714 } 2715 2716 // Return the object as autoreleased. 2717 // RetEffect RE = RetEffect::MakeNotOwned(RetEffect::ObjC); 2718 if (SymbolRef sym = 2719 state->getSVal(Ex, pred->getLocationContext()).getAsSymbol()) { 2720 QualType ResultTy = Ex->getType(); 2721 state = state->set<RefBindings>(sym, RefVal::makeNotOwned(RetEffect::ObjC, 2722 ResultTy)); 2723 } 2724 2725 C.addTransition(state); 2726} 2727 2728void RetainCountChecker::checkPostStmt(const ObjCArrayLiteral *AL, 2729 CheckerContext &C) const { 2730 // Apply the 'MayEscape' to all values. 2731 processObjCLiterals(C, AL); 2732} 2733 2734void RetainCountChecker::checkPostStmt(const ObjCDictionaryLiteral *DL, 2735 CheckerContext &C) const { 2736 // Apply the 'MayEscape' to all keys and values. 2737 processObjCLiterals(C, DL); 2738} 2739 2740void RetainCountChecker::checkPostStmt(const ObjCBoxedExpr *Ex, 2741 CheckerContext &C) const { 2742 const ExplodedNode *Pred = C.getPredecessor(); 2743 const LocationContext *LCtx = Pred->getLocationContext(); 2744 ProgramStateRef State = Pred->getState(); 2745 2746 if (SymbolRef Sym = State->getSVal(Ex, LCtx).getAsSymbol()) { 2747 QualType ResultTy = Ex->getType(); 2748 State = State->set<RefBindings>(Sym, RefVal::makeNotOwned(RetEffect::ObjC, 2749 ResultTy)); 2750 } 2751 2752 C.addTransition(State); 2753} 2754 2755void RetainCountChecker::checkPostCall(const CallEvent &Call, 2756 CheckerContext &C) const { 2757 if (C.wasInlined) 2758 return; 2759 2760 RetainSummaryManager &Summaries = getSummaryManager(C); 2761 const RetainSummary *Summ = Summaries.getSummary(Call, C.getState()); 2762 checkSummary(*Summ, Call, C); 2763} 2764 2765/// GetReturnType - Used to get the return type of a message expression or 2766/// function call with the intention of affixing that type to a tracked symbol. 2767/// While the return type can be queried directly from RetEx, when 2768/// invoking class methods we augment to the return type to be that of 2769/// a pointer to the class (as opposed it just being id). 2770// FIXME: We may be able to do this with related result types instead. 2771// This function is probably overestimating. 2772static QualType GetReturnType(const Expr *RetE, ASTContext &Ctx) { 2773 QualType RetTy = RetE->getType(); 2774 // If RetE is not a message expression just return its type. 2775 // If RetE is a message expression, return its types if it is something 2776 /// more specific than id. 2777 if (const ObjCMessageExpr *ME = dyn_cast<ObjCMessageExpr>(RetE)) 2778 if (const ObjCObjectPointerType *PT = RetTy->getAs<ObjCObjectPointerType>()) 2779 if (PT->isObjCQualifiedIdType() || PT->isObjCIdType() || 2780 PT->isObjCClassType()) { 2781 // At this point we know the return type of the message expression is 2782 // id, id<...>, or Class. If we have an ObjCInterfaceDecl, we know this 2783 // is a call to a class method whose type we can resolve. In such 2784 // cases, promote the return type to XXX* (where XXX is the class). 2785 const ObjCInterfaceDecl *D = ME->getReceiverInterface(); 2786 return !D ? RetTy : 2787 Ctx.getObjCObjectPointerType(Ctx.getObjCInterfaceType(D)); 2788 } 2789 2790 return RetTy; 2791} 2792 2793void RetainCountChecker::checkSummary(const RetainSummary &Summ, 2794 const CallEvent &CallOrMsg, 2795 CheckerContext &C) const { 2796 ProgramStateRef state = C.getState(); 2797 2798 // Evaluate the effect of the arguments. 2799 RefVal::Kind hasErr = (RefVal::Kind) 0; 2800 SourceRange ErrorRange; 2801 SymbolRef ErrorSym = 0; 2802 2803 for (unsigned idx = 0, e = CallOrMsg.getNumArgs(); idx != e; ++idx) { 2804 SVal V = CallOrMsg.getArgSVal(idx); 2805 2806 if (SymbolRef Sym = V.getAsLocSymbol()) { 2807 if (RefBindings::data_type *T = state->get<RefBindings>(Sym)) { 2808 state = updateSymbol(state, Sym, *T, Summ.getArg(idx), hasErr, C); 2809 if (hasErr) { 2810 ErrorRange = CallOrMsg.getArgSourceRange(idx); 2811 ErrorSym = Sym; 2812 break; 2813 } 2814 } 2815 } 2816 } 2817 2818 // Evaluate the effect on the message receiver. 2819 bool ReceiverIsTracked = false; 2820 if (!hasErr) { 2821 const ObjCMethodCall *MsgInvocation = dyn_cast<ObjCMethodCall>(&CallOrMsg); 2822 if (MsgInvocation) { 2823 if (SymbolRef Sym = MsgInvocation->getReceiverSVal().getAsLocSymbol()) { 2824 if (const RefVal *T = state->get<RefBindings>(Sym)) { 2825 ReceiverIsTracked = true; 2826 state = updateSymbol(state, Sym, *T, Summ.getReceiverEffect(), 2827 hasErr, C); 2828 if (hasErr) { 2829 ErrorRange = MsgInvocation->getOriginExpr()->getReceiverRange(); 2830 ErrorSym = Sym; 2831 } 2832 } 2833 } 2834 } 2835 } 2836 2837 // Process any errors. 2838 if (hasErr) { 2839 processNonLeakError(state, ErrorRange, hasErr, ErrorSym, C); 2840 return; 2841 } 2842 2843 // Consult the summary for the return value. 2844 RetEffect RE = Summ.getRetEffect(); 2845 2846 if (RE.getKind() == RetEffect::OwnedWhenTrackedReceiver) { 2847 if (ReceiverIsTracked) 2848 RE = getSummaryManager(C).getObjAllocRetEffect(); 2849 else 2850 RE = RetEffect::MakeNoRet(); 2851 } 2852 2853 switch (RE.getKind()) { 2854 default: 2855 llvm_unreachable("Unhandled RetEffect."); 2856 2857 case RetEffect::NoRet: 2858 // No work necessary. 2859 break; 2860 2861 case RetEffect::OwnedAllocatedSymbol: 2862 case RetEffect::OwnedSymbol: { 2863 SymbolRef Sym = state->getSVal(CallOrMsg.getOriginExpr(), 2864 C.getLocationContext()).getAsSymbol(); 2865 if (!Sym) 2866 break; 2867 2868 // Use the result type from the CallEvent as it automatically adjusts 2869 // for methods/functions that return references. 2870 QualType ResultTy = CallOrMsg.getResultType(); 2871 state = state->set<RefBindings>(Sym, RefVal::makeOwned(RE.getObjKind(), 2872 ResultTy)); 2873 2874 // FIXME: Add a flag to the checker where allocations are assumed to 2875 // *not* fail. (The code below is out-of-date, though.) 2876#if 0 2877 if (RE.getKind() == RetEffect::OwnedAllocatedSymbol) { 2878 bool isFeasible; 2879 state = state.assume(loc::SymbolVal(Sym), true, isFeasible); 2880 assert(isFeasible && "Cannot assume fresh symbol is non-null."); 2881 } 2882#endif 2883 2884 break; 2885 } 2886 2887 case RetEffect::GCNotOwnedSymbol: 2888 case RetEffect::ARCNotOwnedSymbol: 2889 case RetEffect::NotOwnedSymbol: { 2890 const Expr *Ex = CallOrMsg.getOriginExpr(); 2891 SymbolRef Sym = state->getSVal(Ex, C.getLocationContext()).getAsSymbol(); 2892 if (!Sym) 2893 break; 2894 2895 // Use GetReturnType in order to give [NSFoo alloc] the type NSFoo *. 2896 QualType ResultTy = GetReturnType(Ex, C.getASTContext()); 2897 state = state->set<RefBindings>(Sym, RefVal::makeNotOwned(RE.getObjKind(), 2898 ResultTy)); 2899 break; 2900 } 2901 } 2902 2903 // This check is actually necessary; otherwise the statement builder thinks 2904 // we've hit a previously-found path. 2905 // Normally addTransition takes care of this, but we want the node pointer. 2906 ExplodedNode *NewNode; 2907 if (state == C.getState()) { 2908 NewNode = C.getPredecessor(); 2909 } else { 2910 NewNode = C.addTransition(state); 2911 } 2912 2913 // Annotate the node with summary we used. 2914 if (NewNode) { 2915 // FIXME: This is ugly. See checkEndAnalysis for why it's necessary. 2916 if (ShouldResetSummaryLog) { 2917 SummaryLog.clear(); 2918 ShouldResetSummaryLog = false; 2919 } 2920 SummaryLog[NewNode] = &Summ; 2921 } 2922} 2923 2924 2925ProgramStateRef 2926RetainCountChecker::updateSymbol(ProgramStateRef state, SymbolRef sym, 2927 RefVal V, ArgEffect E, RefVal::Kind &hasErr, 2928 CheckerContext &C) const { 2929 // In GC mode [... release] and [... retain] do nothing. 2930 // In ARC mode they shouldn't exist at all, but we just ignore them. 2931 bool IgnoreRetainMsg = C.isObjCGCEnabled(); 2932 if (!IgnoreRetainMsg) 2933 IgnoreRetainMsg = (bool)C.getASTContext().getLangOpts().ObjCAutoRefCount; 2934 2935 switch (E) { 2936 default: 2937 break; 2938 case IncRefMsg: 2939 E = IgnoreRetainMsg ? DoNothing : IncRef; 2940 break; 2941 case DecRefMsg: 2942 E = IgnoreRetainMsg ? DoNothing : DecRef; 2943 break; 2944 case DecRefMsgAndStopTracking: 2945 E = IgnoreRetainMsg ? StopTracking : DecRefAndStopTracking; 2946 break; 2947 case MakeCollectable: 2948 E = C.isObjCGCEnabled() ? DecRef : DoNothing; 2949 break; 2950 case NewAutoreleasePool: 2951 E = C.isObjCGCEnabled() ? DoNothing : NewAutoreleasePool; 2952 break; 2953 } 2954 2955 // Handle all use-after-releases. 2956 if (!C.isObjCGCEnabled() && V.getKind() == RefVal::Released) { 2957 V = V ^ RefVal::ErrorUseAfterRelease; 2958 hasErr = V.getKind(); 2959 return state->set<RefBindings>(sym, V); 2960 } 2961 2962 switch (E) { 2963 case DecRefMsg: 2964 case IncRefMsg: 2965 case MakeCollectable: 2966 case DecRefMsgAndStopTracking: 2967 llvm_unreachable("DecRefMsg/IncRefMsg/MakeCollectable already converted"); 2968 2969 case Dealloc: 2970 // Any use of -dealloc in GC is *bad*. 2971 if (C.isObjCGCEnabled()) { 2972 V = V ^ RefVal::ErrorDeallocGC; 2973 hasErr = V.getKind(); 2974 break; 2975 } 2976 2977 switch (V.getKind()) { 2978 default: 2979 llvm_unreachable("Invalid RefVal state for an explicit dealloc."); 2980 case RefVal::Owned: 2981 // The object immediately transitions to the released state. 2982 V = V ^ RefVal::Released; 2983 V.clearCounts(); 2984 return state->set<RefBindings>(sym, V); 2985 case RefVal::NotOwned: 2986 V = V ^ RefVal::ErrorDeallocNotOwned; 2987 hasErr = V.getKind(); 2988 break; 2989 } 2990 break; 2991 2992 case NewAutoreleasePool: 2993 assert(!C.isObjCGCEnabled()); 2994 return state->add<AutoreleaseStack>(sym); 2995 2996 case MayEscape: 2997 if (V.getKind() == RefVal::Owned) { 2998 V = V ^ RefVal::NotOwned; 2999 break; 3000 } 3001 3002 // Fall-through. 3003 3004 case DoNothing: 3005 return state; 3006 3007 case Autorelease: 3008 if (C.isObjCGCEnabled()) 3009 return state; 3010 3011 // Update the autorelease counts. 3012 state = SendAutorelease(state, ARCountFactory, sym); 3013 V = V.autorelease(); 3014 break; 3015 3016 case StopTracking: 3017 return state->remove<RefBindings>(sym); 3018 3019 case IncRef: 3020 switch (V.getKind()) { 3021 default: 3022 llvm_unreachable("Invalid RefVal state for a retain."); 3023 case RefVal::Owned: 3024 case RefVal::NotOwned: 3025 V = V + 1; 3026 break; 3027 case RefVal::Released: 3028 // Non-GC cases are handled above. 3029 assert(C.isObjCGCEnabled()); 3030 V = (V ^ RefVal::Owned) + 1; 3031 break; 3032 } 3033 break; 3034 3035 case DecRef: 3036 case DecRefBridgedTransfered: 3037 case DecRefAndStopTracking: 3038 switch (V.getKind()) { 3039 default: 3040 // case 'RefVal::Released' handled above. 3041 llvm_unreachable("Invalid RefVal state for a release."); 3042 3043 case RefVal::Owned: 3044 assert(V.getCount() > 0); 3045 if (V.getCount() == 1) 3046 V = V ^ (E == DecRefBridgedTransfered ? 3047 RefVal::NotOwned : RefVal::Released); 3048 else if (E == DecRefAndStopTracking) 3049 return state->remove<RefBindings>(sym); 3050 3051 V = V - 1; 3052 break; 3053 3054 case RefVal::NotOwned: 3055 if (V.getCount() > 0) { 3056 if (E == DecRefAndStopTracking) 3057 return state->remove<RefBindings>(sym); 3058 V = V - 1; 3059 } else { 3060 V = V ^ RefVal::ErrorReleaseNotOwned; 3061 hasErr = V.getKind(); 3062 } 3063 break; 3064 3065 case RefVal::Released: 3066 // Non-GC cases are handled above. 3067 assert(C.isObjCGCEnabled()); 3068 V = V ^ RefVal::ErrorUseAfterRelease; 3069 hasErr = V.getKind(); 3070 break; 3071 } 3072 break; 3073 } 3074 return state->set<RefBindings>(sym, V); 3075} 3076 3077void RetainCountChecker::processNonLeakError(ProgramStateRef St, 3078 SourceRange ErrorRange, 3079 RefVal::Kind ErrorKind, 3080 SymbolRef Sym, 3081 CheckerContext &C) const { 3082 ExplodedNode *N = C.generateSink(St); 3083 if (!N) 3084 return; 3085 3086 CFRefBug *BT; 3087 switch (ErrorKind) { 3088 default: 3089 llvm_unreachable("Unhandled error."); 3090 case RefVal::ErrorUseAfterRelease: 3091 if (!useAfterRelease) 3092 useAfterRelease.reset(new UseAfterRelease()); 3093 BT = &*useAfterRelease; 3094 break; 3095 case RefVal::ErrorReleaseNotOwned: 3096 if (!releaseNotOwned) 3097 releaseNotOwned.reset(new BadRelease()); 3098 BT = &*releaseNotOwned; 3099 break; 3100 case RefVal::ErrorDeallocGC: 3101 if (!deallocGC) 3102 deallocGC.reset(new DeallocGC()); 3103 BT = &*deallocGC; 3104 break; 3105 case RefVal::ErrorDeallocNotOwned: 3106 if (!deallocNotOwned) 3107 deallocNotOwned.reset(new DeallocNotOwned()); 3108 BT = &*deallocNotOwned; 3109 break; 3110 } 3111 3112 assert(BT); 3113 CFRefReport *report = new CFRefReport(*BT, C.getASTContext().getLangOpts(), 3114 C.isObjCGCEnabled(), SummaryLog, 3115 N, Sym); 3116 report->addRange(ErrorRange); 3117 C.EmitReport(report); 3118} 3119 3120//===----------------------------------------------------------------------===// 3121// Handle the return values of retain-count-related functions. 3122//===----------------------------------------------------------------------===// 3123 3124bool RetainCountChecker::evalCall(const CallExpr *CE, CheckerContext &C) const { 3125 // Get the callee. We're only interested in simple C functions. 3126 ProgramStateRef state = C.getState(); 3127 const FunctionDecl *FD = C.getCalleeDecl(CE); 3128 if (!FD) 3129 return false; 3130 3131 IdentifierInfo *II = FD->getIdentifier(); 3132 if (!II) 3133 return false; 3134 3135 // For now, we're only handling the functions that return aliases of their 3136 // arguments: CFRetain and CFMakeCollectable (and their families). 3137 // Eventually we should add other functions we can model entirely, 3138 // such as CFRelease, which don't invalidate their arguments or globals. 3139 if (CE->getNumArgs() != 1) 3140 return false; 3141 3142 // Get the name of the function. 3143 StringRef FName = II->getName(); 3144 FName = FName.substr(FName.find_first_not_of('_')); 3145 3146 // See if it's one of the specific functions we know how to eval. 3147 bool canEval = false; 3148 3149 QualType ResultTy = CE->getCallReturnType(); 3150 if (ResultTy->isObjCIdType()) { 3151 // Handle: id NSMakeCollectable(CFTypeRef) 3152 canEval = II->isStr("NSMakeCollectable"); 3153 } else if (ResultTy->isPointerType()) { 3154 // Handle: (CF|CG)Retain 3155 // CFMakeCollectable 3156 // It's okay to be a little sloppy here (CGMakeCollectable doesn't exist). 3157 if (cocoa::isRefType(ResultTy, "CF", FName) || 3158 cocoa::isRefType(ResultTy, "CG", FName)) { 3159 canEval = isRetain(FD, FName) || isMakeCollectable(FD, FName); 3160 } 3161 } 3162 3163 if (!canEval) 3164 return false; 3165 3166 // Bind the return value. 3167 const LocationContext *LCtx = C.getLocationContext(); 3168 SVal RetVal = state->getSVal(CE->getArg(0), LCtx); 3169 if (RetVal.isUnknown()) { 3170 // If the receiver is unknown, conjure a return value. 3171 SValBuilder &SVB = C.getSValBuilder(); 3172 unsigned Count = C.getCurrentBlockCount(); 3173 RetVal = SVB.getConjuredSymbolVal(0, CE, LCtx, ResultTy, Count); 3174 } 3175 state = state->BindExpr(CE, LCtx, RetVal, false); 3176 3177 // FIXME: This should not be necessary, but otherwise the argument seems to be 3178 // considered alive during the next statement. 3179 if (const MemRegion *ArgRegion = RetVal.getAsRegion()) { 3180 // Save the refcount status of the argument. 3181 SymbolRef Sym = RetVal.getAsLocSymbol(); 3182 RefBindings::data_type *Binding = 0; 3183 if (Sym) 3184 Binding = state->get<RefBindings>(Sym); 3185 3186 // Invalidate the argument region. 3187 unsigned Count = C.getCurrentBlockCount(); 3188 state = state->invalidateRegions(ArgRegion, CE, Count, LCtx); 3189 3190 // Restore the refcount status of the argument. 3191 if (Binding) 3192 state = state->set<RefBindings>(Sym, *Binding); 3193 } 3194 3195 C.addTransition(state); 3196 return true; 3197} 3198 3199//===----------------------------------------------------------------------===// 3200// Handle return statements. 3201//===----------------------------------------------------------------------===// 3202 3203// Return true if the current LocationContext has no caller context. 3204static bool inTopFrame(CheckerContext &C) { 3205 const LocationContext *LC = C.getLocationContext(); 3206 return LC->getParent() == 0; 3207} 3208 3209void RetainCountChecker::checkPreStmt(const ReturnStmt *S, 3210 CheckerContext &C) const { 3211 3212 // Only adjust the reference count if this is the top-level call frame, 3213 // and not the result of inlining. In the future, we should do 3214 // better checking even for inlined calls, and see if they match 3215 // with their expected semantics (e.g., the method should return a retained 3216 // object, etc.). 3217 if (!inTopFrame(C)) 3218 return; 3219 3220 const Expr *RetE = S->getRetValue(); 3221 if (!RetE) 3222 return; 3223 3224 ProgramStateRef state = C.getState(); 3225 SymbolRef Sym = 3226 state->getSValAsScalarOrLoc(RetE, C.getLocationContext()).getAsLocSymbol(); 3227 if (!Sym) 3228 return; 3229 3230 // Get the reference count binding (if any). 3231 const RefVal *T = state->get<RefBindings>(Sym); 3232 if (!T) 3233 return; 3234 3235 // Change the reference count. 3236 RefVal X = *T; 3237 3238 switch (X.getKind()) { 3239 case RefVal::Owned: { 3240 unsigned cnt = X.getCount(); 3241 assert(cnt > 0); 3242 X.setCount(cnt - 1); 3243 X = X ^ RefVal::ReturnedOwned; 3244 break; 3245 } 3246 3247 case RefVal::NotOwned: { 3248 unsigned cnt = X.getCount(); 3249 if (cnt) { 3250 X.setCount(cnt - 1); 3251 X = X ^ RefVal::ReturnedOwned; 3252 } 3253 else { 3254 X = X ^ RefVal::ReturnedNotOwned; 3255 } 3256 break; 3257 } 3258 3259 default: 3260 return; 3261 } 3262 3263 // Update the binding. 3264 state = state->set<RefBindings>(Sym, X); 3265 ExplodedNode *Pred = C.addTransition(state); 3266 3267 // At this point we have updated the state properly. 3268 // Everything after this is merely checking to see if the return value has 3269 // been over- or under-retained. 3270 3271 // Did we cache out? 3272 if (!Pred) 3273 return; 3274 3275 // Update the autorelease counts. 3276 static SimpleProgramPointTag 3277 AutoreleaseTag("RetainCountChecker : Autorelease"); 3278 GenericNodeBuilderRefCount Bd(C, &AutoreleaseTag); 3279 llvm::tie(Pred, state) = handleAutoreleaseCounts(state, Bd, Pred, C, Sym, X); 3280 3281 // Did we cache out? 3282 if (!Pred) 3283 return; 3284 3285 // Get the updated binding. 3286 T = state->get<RefBindings>(Sym); 3287 assert(T); 3288 X = *T; 3289 3290 // Consult the summary of the enclosing method. 3291 RetainSummaryManager &Summaries = getSummaryManager(C); 3292 const Decl *CD = &Pred->getCodeDecl(); 3293 RetEffect RE = RetEffect::MakeNoRet(); 3294 3295 // FIXME: What is the convention for blocks? Is there one? 3296 if (const ObjCMethodDecl *MD = dyn_cast<ObjCMethodDecl>(CD)) { 3297 const RetainSummary *Summ = Summaries.getMethodSummary(MD); 3298 RE = Summ->getRetEffect(); 3299 } else if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(CD)) { 3300 if (!isa<CXXMethodDecl>(FD)) { 3301 const RetainSummary *Summ = Summaries.getFunctionSummary(FD); 3302 RE = Summ->getRetEffect(); 3303 } 3304 } 3305 3306 checkReturnWithRetEffect(S, C, Pred, RE, X, Sym, state); 3307} 3308 3309void RetainCountChecker::checkReturnWithRetEffect(const ReturnStmt *S, 3310 CheckerContext &C, 3311 ExplodedNode *Pred, 3312 RetEffect RE, RefVal X, 3313 SymbolRef Sym, 3314 ProgramStateRef state) const { 3315 // Any leaks or other errors? 3316 if (X.isReturnedOwned() && X.getCount() == 0) { 3317 if (RE.getKind() != RetEffect::NoRet) { 3318 bool hasError = false; 3319 if (C.isObjCGCEnabled() && RE.getObjKind() == RetEffect::ObjC) { 3320 // Things are more complicated with garbage collection. If the 3321 // returned object is suppose to be an Objective-C object, we have 3322 // a leak (as the caller expects a GC'ed object) because no 3323 // method should return ownership unless it returns a CF object. 3324 hasError = true; 3325 X = X ^ RefVal::ErrorGCLeakReturned; 3326 } 3327 else if (!RE.isOwned()) { 3328 // Either we are using GC and the returned object is a CF type 3329 // or we aren't using GC. In either case, we expect that the 3330 // enclosing method is expected to return ownership. 3331 hasError = true; 3332 X = X ^ RefVal::ErrorLeakReturned; 3333 } 3334 3335 if (hasError) { 3336 // Generate an error node. 3337 state = state->set<RefBindings>(Sym, X); 3338 3339 static SimpleProgramPointTag 3340 ReturnOwnLeakTag("RetainCountChecker : ReturnsOwnLeak"); 3341 ExplodedNode *N = C.addTransition(state, Pred, &ReturnOwnLeakTag); 3342 if (N) { 3343 const LangOptions &LOpts = C.getASTContext().getLangOpts(); 3344 bool GCEnabled = C.isObjCGCEnabled(); 3345 CFRefReport *report = 3346 new CFRefLeakReport(*getLeakAtReturnBug(LOpts, GCEnabled), 3347 LOpts, GCEnabled, SummaryLog, 3348 N, Sym, C); 3349 C.EmitReport(report); 3350 } 3351 } 3352 } 3353 } else if (X.isReturnedNotOwned()) { 3354 if (RE.isOwned()) { 3355 // Trying to return a not owned object to a caller expecting an 3356 // owned object. 3357 state = state->set<RefBindings>(Sym, X ^ RefVal::ErrorReturnedNotOwned); 3358 3359 static SimpleProgramPointTag 3360 ReturnNotOwnedTag("RetainCountChecker : ReturnNotOwnedForOwned"); 3361 ExplodedNode *N = C.addTransition(state, Pred, &ReturnNotOwnedTag); 3362 if (N) { 3363 if (!returnNotOwnedForOwned) 3364 returnNotOwnedForOwned.reset(new ReturnedNotOwnedForOwned()); 3365 3366 CFRefReport *report = 3367 new CFRefReport(*returnNotOwnedForOwned, 3368 C.getASTContext().getLangOpts(), 3369 C.isObjCGCEnabled(), SummaryLog, N, Sym); 3370 C.EmitReport(report); 3371 } 3372 } 3373 } 3374} 3375 3376//===----------------------------------------------------------------------===// 3377// Check various ways a symbol can be invalidated. 3378//===----------------------------------------------------------------------===// 3379 3380void RetainCountChecker::checkBind(SVal loc, SVal val, const Stmt *S, 3381 CheckerContext &C) const { 3382 // Are we storing to something that causes the value to "escape"? 3383 bool escapes = true; 3384 3385 // A value escapes in three possible cases (this may change): 3386 // 3387 // (1) we are binding to something that is not a memory region. 3388 // (2) we are binding to a memregion that does not have stack storage 3389 // (3) we are binding to a memregion with stack storage that the store 3390 // does not understand. 3391 ProgramStateRef state = C.getState(); 3392 3393 if (loc::MemRegionVal *regionLoc = dyn_cast<loc::MemRegionVal>(&loc)) { 3394 escapes = !regionLoc->getRegion()->hasStackStorage(); 3395 3396 if (!escapes) { 3397 // To test (3), generate a new state with the binding added. If it is 3398 // the same state, then it escapes (since the store cannot represent 3399 // the binding). 3400 // Do this only if we know that the store is not supposed to generate the 3401 // same state. 3402 SVal StoredVal = state->getSVal(regionLoc->getRegion()); 3403 if (StoredVal != val) 3404 escapes = (state == (state->bindLoc(*regionLoc, val))); 3405 } 3406 if (!escapes) { 3407 // Case 4: We do not currently model what happens when a symbol is 3408 // assigned to a struct field, so be conservative here and let the symbol 3409 // go. TODO: This could definitely be improved upon. 3410 escapes = !isa<VarRegion>(regionLoc->getRegion()); 3411 } 3412 } 3413 3414 // If our store can represent the binding and we aren't storing to something 3415 // that doesn't have local storage then just return and have the simulation 3416 // state continue as is. 3417 if (!escapes) 3418 return; 3419 3420 // Otherwise, find all symbols referenced by 'val' that we are tracking 3421 // and stop tracking them. 3422 state = state->scanReachableSymbols<StopTrackingCallback>(val).getState(); 3423 C.addTransition(state); 3424} 3425 3426ProgramStateRef RetainCountChecker::evalAssume(ProgramStateRef state, 3427 SVal Cond, 3428 bool Assumption) const { 3429 3430 // FIXME: We may add to the interface of evalAssume the list of symbols 3431 // whose assumptions have changed. For now we just iterate through the 3432 // bindings and check if any of the tracked symbols are NULL. This isn't 3433 // too bad since the number of symbols we will track in practice are 3434 // probably small and evalAssume is only called at branches and a few 3435 // other places. 3436 RefBindings B = state->get<RefBindings>(); 3437 3438 if (B.isEmpty()) 3439 return state; 3440 3441 bool changed = false; 3442 RefBindings::Factory &RefBFactory = state->get_context<RefBindings>(); 3443 3444 for (RefBindings::iterator I = B.begin(), E = B.end(); I != E; ++I) { 3445 // Check if the symbol is null (or equal to any constant). 3446 // If this is the case, stop tracking the symbol. 3447 if (state->getSymVal(I.getKey())) { 3448 changed = true; 3449 B = RefBFactory.remove(B, I.getKey()); 3450 } 3451 } 3452 3453 if (changed) 3454 state = state->set<RefBindings>(B); 3455 3456 return state; 3457} 3458 3459ProgramStateRef 3460RetainCountChecker::checkRegionChanges(ProgramStateRef state, 3461 const StoreManager::InvalidatedSymbols *invalidated, 3462 ArrayRef<const MemRegion *> ExplicitRegions, 3463 ArrayRef<const MemRegion *> Regions, 3464 const CallEvent *Call) const { 3465 if (!invalidated) 3466 return state; 3467 3468 llvm::SmallPtrSet<SymbolRef, 8> WhitelistedSymbols; 3469 for (ArrayRef<const MemRegion *>::iterator I = ExplicitRegions.begin(), 3470 E = ExplicitRegions.end(); I != E; ++I) { 3471 if (const SymbolicRegion *SR = (*I)->StripCasts()->getAs<SymbolicRegion>()) 3472 WhitelistedSymbols.insert(SR->getSymbol()); 3473 } 3474 3475 for (StoreManager::InvalidatedSymbols::const_iterator I=invalidated->begin(), 3476 E = invalidated->end(); I!=E; ++I) { 3477 SymbolRef sym = *I; 3478 if (WhitelistedSymbols.count(sym)) 3479 continue; 3480 // Remove any existing reference-count binding. 3481 state = state->remove<RefBindings>(sym); 3482 } 3483 return state; 3484} 3485 3486//===----------------------------------------------------------------------===// 3487// Handle dead symbols and end-of-path. 3488//===----------------------------------------------------------------------===// 3489 3490std::pair<ExplodedNode *, ProgramStateRef > 3491RetainCountChecker::handleAutoreleaseCounts(ProgramStateRef state, 3492 GenericNodeBuilderRefCount Bd, 3493 ExplodedNode *Pred, 3494 CheckerContext &Ctx, 3495 SymbolRef Sym, RefVal V) const { 3496 unsigned ACnt = V.getAutoreleaseCount(); 3497 3498 // No autorelease counts? Nothing to be done. 3499 if (!ACnt) 3500 return std::make_pair(Pred, state); 3501 3502 assert(!Ctx.isObjCGCEnabled() && "Autorelease counts in GC mode?"); 3503 unsigned Cnt = V.getCount(); 3504 3505 // FIXME: Handle sending 'autorelease' to already released object. 3506 3507 if (V.getKind() == RefVal::ReturnedOwned) 3508 ++Cnt; 3509 3510 if (ACnt <= Cnt) { 3511 if (ACnt == Cnt) { 3512 V.clearCounts(); 3513 if (V.getKind() == RefVal::ReturnedOwned) 3514 V = V ^ RefVal::ReturnedNotOwned; 3515 else 3516 V = V ^ RefVal::NotOwned; 3517 } else { 3518 V.setCount(Cnt - ACnt); 3519 V.setAutoreleaseCount(0); 3520 } 3521 state = state->set<RefBindings>(Sym, V); 3522 ExplodedNode *N = Bd.MakeNode(state, Pred); 3523 if (N == 0) 3524 state = 0; 3525 return std::make_pair(N, state); 3526 } 3527 3528 // Woah! More autorelease counts then retain counts left. 3529 // Emit hard error. 3530 V = V ^ RefVal::ErrorOverAutorelease; 3531 state = state->set<RefBindings>(Sym, V); 3532 3533 if (ExplodedNode *N = Bd.MakeNode(state, Pred, true)) { 3534 SmallString<128> sbuf; 3535 llvm::raw_svector_ostream os(sbuf); 3536 os << "Object over-autoreleased: object was sent -autorelease "; 3537 if (V.getAutoreleaseCount() > 1) 3538 os << V.getAutoreleaseCount() << " times "; 3539 os << "but the object has a +" << V.getCount() << " retain count"; 3540 3541 if (!overAutorelease) 3542 overAutorelease.reset(new OverAutorelease()); 3543 3544 const LangOptions &LOpts = Ctx.getASTContext().getLangOpts(); 3545 CFRefReport *report = 3546 new CFRefReport(*overAutorelease, LOpts, /* GCEnabled = */ false, 3547 SummaryLog, N, Sym, os.str()); 3548 Ctx.EmitReport(report); 3549 } 3550 3551 return std::make_pair((ExplodedNode *)0, (ProgramStateRef )0); 3552} 3553 3554ProgramStateRef 3555RetainCountChecker::handleSymbolDeath(ProgramStateRef state, 3556 SymbolRef sid, RefVal V, 3557 SmallVectorImpl<SymbolRef> &Leaked) const { 3558 bool hasLeak = false; 3559 if (V.isOwned()) 3560 hasLeak = true; 3561 else if (V.isNotOwned() || V.isReturnedOwned()) 3562 hasLeak = (V.getCount() > 0); 3563 3564 if (!hasLeak) 3565 return state->remove<RefBindings>(sid); 3566 3567 Leaked.push_back(sid); 3568 return state->set<RefBindings>(sid, V ^ RefVal::ErrorLeak); 3569} 3570 3571ExplodedNode * 3572RetainCountChecker::processLeaks(ProgramStateRef state, 3573 SmallVectorImpl<SymbolRef> &Leaked, 3574 GenericNodeBuilderRefCount &Builder, 3575 CheckerContext &Ctx, 3576 ExplodedNode *Pred) const { 3577 if (Leaked.empty()) 3578 return Pred; 3579 3580 // Generate an intermediate node representing the leak point. 3581 ExplodedNode *N = Builder.MakeNode(state, Pred); 3582 3583 if (N) { 3584 for (SmallVectorImpl<SymbolRef>::iterator 3585 I = Leaked.begin(), E = Leaked.end(); I != E; ++I) { 3586 3587 const LangOptions &LOpts = Ctx.getASTContext().getLangOpts(); 3588 bool GCEnabled = Ctx.isObjCGCEnabled(); 3589 CFRefBug *BT = Pred ? getLeakWithinFunctionBug(LOpts, GCEnabled) 3590 : getLeakAtReturnBug(LOpts, GCEnabled); 3591 assert(BT && "BugType not initialized."); 3592 3593 CFRefLeakReport *report = new CFRefLeakReport(*BT, LOpts, GCEnabled, 3594 SummaryLog, N, *I, Ctx); 3595 Ctx.EmitReport(report); 3596 } 3597 } 3598 3599 return N; 3600} 3601 3602void RetainCountChecker::checkEndPath(CheckerContext &Ctx) const { 3603 ProgramStateRef state = Ctx.getState(); 3604 GenericNodeBuilderRefCount Bd(Ctx); 3605 RefBindings B = state->get<RefBindings>(); 3606 ExplodedNode *Pred = Ctx.getPredecessor(); 3607 3608 for (RefBindings::iterator I = B.begin(), E = B.end(); I != E; ++I) { 3609 llvm::tie(Pred, state) = handleAutoreleaseCounts(state, Bd, Pred, Ctx, 3610 I->first, I->second); 3611 if (!state) 3612 return; 3613 } 3614 3615 // If the current LocationContext has a parent, don't check for leaks. 3616 // We will do that later. 3617 // FIXME: we should instead check for imblances of the retain/releases, 3618 // and suggest annotations. 3619 if (Ctx.getLocationContext()->getParent()) 3620 return; 3621 3622 B = state->get<RefBindings>(); 3623 SmallVector<SymbolRef, 10> Leaked; 3624 3625 for (RefBindings::iterator I = B.begin(), E = B.end(); I != E; ++I) 3626 state = handleSymbolDeath(state, I->first, I->second, Leaked); 3627 3628 processLeaks(state, Leaked, Bd, Ctx, Pred); 3629} 3630 3631const ProgramPointTag * 3632RetainCountChecker::getDeadSymbolTag(SymbolRef sym) const { 3633 const SimpleProgramPointTag *&tag = DeadSymbolTags[sym]; 3634 if (!tag) { 3635 SmallString<64> buf; 3636 llvm::raw_svector_ostream out(buf); 3637 out << "RetainCountChecker : Dead Symbol : "; 3638 sym->dumpToStream(out); 3639 tag = new SimpleProgramPointTag(out.str()); 3640 } 3641 return tag; 3642} 3643 3644void RetainCountChecker::checkDeadSymbols(SymbolReaper &SymReaper, 3645 CheckerContext &C) const { 3646 ExplodedNode *Pred = C.getPredecessor(); 3647 3648 ProgramStateRef state = C.getState(); 3649 RefBindings B = state->get<RefBindings>(); 3650 3651 // Update counts from autorelease pools 3652 for (SymbolReaper::dead_iterator I = SymReaper.dead_begin(), 3653 E = SymReaper.dead_end(); I != E; ++I) { 3654 SymbolRef Sym = *I; 3655 if (const RefVal *T = B.lookup(Sym)){ 3656 // Use the symbol as the tag. 3657 // FIXME: This might not be as unique as we would like. 3658 GenericNodeBuilderRefCount Bd(C, getDeadSymbolTag(Sym)); 3659 llvm::tie(Pred, state) = handleAutoreleaseCounts(state, Bd, Pred, C, 3660 Sym, *T); 3661 if (!state) 3662 return; 3663 } 3664 } 3665 3666 B = state->get<RefBindings>(); 3667 SmallVector<SymbolRef, 10> Leaked; 3668 3669 for (SymbolReaper::dead_iterator I = SymReaper.dead_begin(), 3670 E = SymReaper.dead_end(); I != E; ++I) { 3671 if (const RefVal *T = B.lookup(*I)) 3672 state = handleSymbolDeath(state, *I, *T, Leaked); 3673 } 3674 3675 { 3676 GenericNodeBuilderRefCount Bd(C, this); 3677 Pred = processLeaks(state, Leaked, Bd, C, Pred); 3678 } 3679 3680 // Did we cache out? 3681 if (!Pred) 3682 return; 3683 3684 // Now generate a new node that nukes the old bindings. 3685 RefBindings::Factory &F = state->get_context<RefBindings>(); 3686 3687 for (SymbolReaper::dead_iterator I = SymReaper.dead_begin(), 3688 E = SymReaper.dead_end(); I != E; ++I) 3689 B = F.remove(B, *I); 3690 3691 state = state->set<RefBindings>(B); 3692 C.addTransition(state, Pred); 3693} 3694 3695//===----------------------------------------------------------------------===// 3696// Debug printing of refcount bindings and autorelease pools. 3697//===----------------------------------------------------------------------===// 3698 3699static void PrintPool(raw_ostream &Out, SymbolRef Sym, 3700 ProgramStateRef State) { 3701 Out << ' '; 3702 if (Sym) 3703 Sym->dumpToStream(Out); 3704 else 3705 Out << "<pool>"; 3706 Out << ":{"; 3707 3708 // Get the contents of the pool. 3709 if (const ARCounts *Cnts = State->get<AutoreleasePoolContents>(Sym)) 3710 for (ARCounts::iterator I = Cnts->begin(), E = Cnts->end(); I != E; ++I) 3711 Out << '(' << I.getKey() << ',' << I.getData() << ')'; 3712 3713 Out << '}'; 3714} 3715 3716static bool UsesAutorelease(ProgramStateRef state) { 3717 // A state uses autorelease if it allocated an autorelease pool or if it has 3718 // objects in the caller's autorelease pool. 3719 return !state->get<AutoreleaseStack>().isEmpty() || 3720 state->get<AutoreleasePoolContents>(SymbolRef()); 3721} 3722 3723void RetainCountChecker::printState(raw_ostream &Out, ProgramStateRef State, 3724 const char *NL, const char *Sep) const { 3725 3726 RefBindings B = State->get<RefBindings>(); 3727 3728 if (!B.isEmpty()) 3729 Out << Sep << NL; 3730 3731 for (RefBindings::iterator I = B.begin(), E = B.end(); I != E; ++I) { 3732 Out << I->first << " : "; 3733 I->second.print(Out); 3734 Out << NL; 3735 } 3736 3737 // Print the autorelease stack. 3738 if (UsesAutorelease(State)) { 3739 Out << Sep << NL << "AR pool stack:"; 3740 ARStack Stack = State->get<AutoreleaseStack>(); 3741 3742 PrintPool(Out, SymbolRef(), State); // Print the caller's pool. 3743 for (ARStack::iterator I = Stack.begin(), E = Stack.end(); I != E; ++I) 3744 PrintPool(Out, *I, State); 3745 3746 Out << NL; 3747 } 3748} 3749 3750//===----------------------------------------------------------------------===// 3751// Checker registration. 3752//===----------------------------------------------------------------------===// 3753 3754void ento::registerRetainCountChecker(CheckerManager &Mgr) { 3755 Mgr.registerChecker<RetainCountChecker>(); 3756} 3757 3758