RetainCountChecker.cpp revision 740d490593e0de8732a697c9f77b90ddd463863b
1//==-- RetainCountChecker.cpp - Checks for leaks and other issues -*- C++ -*--// 2// 3// The LLVM Compiler Infrastructure 4// 5// This file is distributed under the University of Illinois Open Source 6// License. See LICENSE.TXT for details. 7// 8//===----------------------------------------------------------------------===// 9// 10// This file defines the methods for RetainCountChecker, which implements 11// a reference count checker for Core Foundation and Cocoa on (Mac OS X). 12// 13//===----------------------------------------------------------------------===// 14 15#include "ClangSACheckers.h" 16#include "clang/AST/DeclObjC.h" 17#include "clang/AST/DeclCXX.h" 18#include "clang/Basic/LangOptions.h" 19#include "clang/Basic/SourceManager.h" 20#include "clang/Analysis/DomainSpecific/CocoaConventions.h" 21#include "clang/AST/ParentMap.h" 22#include "clang/StaticAnalyzer/Core/Checker.h" 23#include "clang/StaticAnalyzer/Core/CheckerManager.h" 24#include "clang/StaticAnalyzer/Core/BugReporter/BugType.h" 25#include "clang/StaticAnalyzer/Core/BugReporter/PathDiagnostic.h" 26#include "clang/StaticAnalyzer/Core/PathSensitive/CheckerContext.h" 27#include "clang/StaticAnalyzer/Core/PathSensitive/ProgramStateTrait.h" 28#include "clang/StaticAnalyzer/Core/PathSensitive/SymbolManager.h" 29#include "clang/StaticAnalyzer/Core/PathSensitive/ObjCMessage.h" 30#include "llvm/ADT/DenseMap.h" 31#include "llvm/ADT/FoldingSet.h" 32#include "llvm/ADT/ImmutableList.h" 33#include "llvm/ADT/ImmutableMap.h" 34#include "llvm/ADT/SmallString.h" 35#include "llvm/ADT/STLExtras.h" 36#include "llvm/ADT/StringExtras.h" 37#include <cstdarg> 38 39using namespace clang; 40using namespace ento; 41using llvm::StrInStrNoCase; 42 43namespace { 44/// Wrapper around different kinds of node builder, so that helper functions 45/// can have a common interface. 46class GenericNodeBuilderRefCount { 47 CheckerContext *C; 48 const ProgramPointTag *tag; 49public: 50 GenericNodeBuilderRefCount(CheckerContext &c, 51 const ProgramPointTag *t = 0) 52 : C(&c), tag(t){} 53 54 ExplodedNode *MakeNode(ProgramStateRef state, ExplodedNode *Pred, 55 bool MarkAsSink = false) { 56 return C->addTransition(state, Pred, tag, MarkAsSink); 57 } 58}; 59} // end anonymous namespace 60 61//===----------------------------------------------------------------------===// 62// Primitives used for constructing summaries for function/method calls. 63//===----------------------------------------------------------------------===// 64 65/// ArgEffect is used to summarize a function/method call's effect on a 66/// particular argument. 67enum ArgEffect { DoNothing, Autorelease, Dealloc, DecRef, DecRefMsg, 68 DecRefBridgedTransfered, 69 IncRefMsg, IncRef, MakeCollectable, MayEscape, 70 NewAutoreleasePool, StopTracking }; 71 72namespace llvm { 73template <> struct FoldingSetTrait<ArgEffect> { 74static inline void Profile(const ArgEffect X, FoldingSetNodeID& ID) { 75 ID.AddInteger((unsigned) X); 76} 77}; 78} // end llvm namespace 79 80/// ArgEffects summarizes the effects of a function/method call on all of 81/// its arguments. 82typedef llvm::ImmutableMap<unsigned,ArgEffect> ArgEffects; 83 84namespace { 85 86/// RetEffect is used to summarize a function/method call's behavior with 87/// respect to its return value. 88class RetEffect { 89public: 90 enum Kind { NoRet, OwnedSymbol, OwnedAllocatedSymbol, 91 NotOwnedSymbol, GCNotOwnedSymbol, ARCNotOwnedSymbol, 92 OwnedWhenTrackedReceiver }; 93 94 enum ObjKind { CF, ObjC, AnyObj }; 95 96private: 97 Kind K; 98 ObjKind O; 99 100 RetEffect(Kind k, ObjKind o = AnyObj) : K(k), O(o) {} 101 102public: 103 Kind getKind() const { return K; } 104 105 ObjKind getObjKind() const { return O; } 106 107 bool isOwned() const { 108 return K == OwnedSymbol || K == OwnedAllocatedSymbol || 109 K == OwnedWhenTrackedReceiver; 110 } 111 112 bool operator==(const RetEffect &Other) const { 113 return K == Other.K && O == Other.O; 114 } 115 116 static RetEffect MakeOwnedWhenTrackedReceiver() { 117 return RetEffect(OwnedWhenTrackedReceiver, ObjC); 118 } 119 120 static RetEffect MakeOwned(ObjKind o, bool isAllocated = false) { 121 return RetEffect(isAllocated ? OwnedAllocatedSymbol : OwnedSymbol, o); 122 } 123 static RetEffect MakeNotOwned(ObjKind o) { 124 return RetEffect(NotOwnedSymbol, o); 125 } 126 static RetEffect MakeGCNotOwned() { 127 return RetEffect(GCNotOwnedSymbol, ObjC); 128 } 129 static RetEffect MakeARCNotOwned() { 130 return RetEffect(ARCNotOwnedSymbol, ObjC); 131 } 132 static RetEffect MakeNoRet() { 133 return RetEffect(NoRet); 134 } 135 136 void Profile(llvm::FoldingSetNodeID& ID) const { 137 ID.AddInteger((unsigned) K); 138 ID.AddInteger((unsigned) O); 139 } 140}; 141 142//===----------------------------------------------------------------------===// 143// Reference-counting logic (typestate + counts). 144//===----------------------------------------------------------------------===// 145 146class RefVal { 147public: 148 enum Kind { 149 Owned = 0, // Owning reference. 150 NotOwned, // Reference is not owned by still valid (not freed). 151 Released, // Object has been released. 152 ReturnedOwned, // Returned object passes ownership to caller. 153 ReturnedNotOwned, // Return object does not pass ownership to caller. 154 ERROR_START, 155 ErrorDeallocNotOwned, // -dealloc called on non-owned object. 156 ErrorDeallocGC, // Calling -dealloc with GC enabled. 157 ErrorUseAfterRelease, // Object used after released. 158 ErrorReleaseNotOwned, // Release of an object that was not owned. 159 ERROR_LEAK_START, 160 ErrorLeak, // A memory leak due to excessive reference counts. 161 ErrorLeakReturned, // A memory leak due to the returning method not having 162 // the correct naming conventions. 163 ErrorGCLeakReturned, 164 ErrorOverAutorelease, 165 ErrorReturnedNotOwned 166 }; 167 168private: 169 Kind kind; 170 RetEffect::ObjKind okind; 171 unsigned Cnt; 172 unsigned ACnt; 173 QualType T; 174 175 RefVal(Kind k, RetEffect::ObjKind o, unsigned cnt, unsigned acnt, QualType t) 176 : kind(k), okind(o), Cnt(cnt), ACnt(acnt), T(t) {} 177 178public: 179 Kind getKind() const { return kind; } 180 181 RetEffect::ObjKind getObjKind() const { return okind; } 182 183 unsigned getCount() const { return Cnt; } 184 unsigned getAutoreleaseCount() const { return ACnt; } 185 unsigned getCombinedCounts() const { return Cnt + ACnt; } 186 void clearCounts() { Cnt = 0; ACnt = 0; } 187 void setCount(unsigned i) { Cnt = i; } 188 void setAutoreleaseCount(unsigned i) { ACnt = i; } 189 190 QualType getType() const { return T; } 191 192 bool isOwned() const { 193 return getKind() == Owned; 194 } 195 196 bool isNotOwned() const { 197 return getKind() == NotOwned; 198 } 199 200 bool isReturnedOwned() const { 201 return getKind() == ReturnedOwned; 202 } 203 204 bool isReturnedNotOwned() const { 205 return getKind() == ReturnedNotOwned; 206 } 207 208 static RefVal makeOwned(RetEffect::ObjKind o, QualType t, 209 unsigned Count = 1) { 210 return RefVal(Owned, o, Count, 0, t); 211 } 212 213 static RefVal makeNotOwned(RetEffect::ObjKind o, QualType t, 214 unsigned Count = 0) { 215 return RefVal(NotOwned, o, Count, 0, t); 216 } 217 218 // Comparison, profiling, and pretty-printing. 219 220 bool operator==(const RefVal& X) const { 221 return kind == X.kind && Cnt == X.Cnt && T == X.T && ACnt == X.ACnt; 222 } 223 224 RefVal operator-(size_t i) const { 225 return RefVal(getKind(), getObjKind(), getCount() - i, 226 getAutoreleaseCount(), getType()); 227 } 228 229 RefVal operator+(size_t i) const { 230 return RefVal(getKind(), getObjKind(), getCount() + i, 231 getAutoreleaseCount(), getType()); 232 } 233 234 RefVal operator^(Kind k) const { 235 return RefVal(k, getObjKind(), getCount(), getAutoreleaseCount(), 236 getType()); 237 } 238 239 RefVal autorelease() const { 240 return RefVal(getKind(), getObjKind(), getCount(), getAutoreleaseCount()+1, 241 getType()); 242 } 243 244 void Profile(llvm::FoldingSetNodeID& ID) const { 245 ID.AddInteger((unsigned) kind); 246 ID.AddInteger(Cnt); 247 ID.AddInteger(ACnt); 248 ID.Add(T); 249 } 250 251 void print(raw_ostream &Out) const; 252}; 253 254void RefVal::print(raw_ostream &Out) const { 255 if (!T.isNull()) 256 Out << "Tracked " << T.getAsString() << '/'; 257 258 switch (getKind()) { 259 default: llvm_unreachable("Invalid RefVal kind"); 260 case Owned: { 261 Out << "Owned"; 262 unsigned cnt = getCount(); 263 if (cnt) Out << " (+ " << cnt << ")"; 264 break; 265 } 266 267 case NotOwned: { 268 Out << "NotOwned"; 269 unsigned cnt = getCount(); 270 if (cnt) Out << " (+ " << cnt << ")"; 271 break; 272 } 273 274 case ReturnedOwned: { 275 Out << "ReturnedOwned"; 276 unsigned cnt = getCount(); 277 if (cnt) Out << " (+ " << cnt << ")"; 278 break; 279 } 280 281 case ReturnedNotOwned: { 282 Out << "ReturnedNotOwned"; 283 unsigned cnt = getCount(); 284 if (cnt) Out << " (+ " << cnt << ")"; 285 break; 286 } 287 288 case Released: 289 Out << "Released"; 290 break; 291 292 case ErrorDeallocGC: 293 Out << "-dealloc (GC)"; 294 break; 295 296 case ErrorDeallocNotOwned: 297 Out << "-dealloc (not-owned)"; 298 break; 299 300 case ErrorLeak: 301 Out << "Leaked"; 302 break; 303 304 case ErrorLeakReturned: 305 Out << "Leaked (Bad naming)"; 306 break; 307 308 case ErrorGCLeakReturned: 309 Out << "Leaked (GC-ed at return)"; 310 break; 311 312 case ErrorUseAfterRelease: 313 Out << "Use-After-Release [ERROR]"; 314 break; 315 316 case ErrorReleaseNotOwned: 317 Out << "Release of Not-Owned [ERROR]"; 318 break; 319 320 case RefVal::ErrorOverAutorelease: 321 Out << "Over autoreleased"; 322 break; 323 324 case RefVal::ErrorReturnedNotOwned: 325 Out << "Non-owned object returned instead of owned"; 326 break; 327 } 328 329 if (ACnt) { 330 Out << " [ARC +" << ACnt << ']'; 331 } 332} 333} //end anonymous namespace 334 335//===----------------------------------------------------------------------===// 336// RefBindings - State used to track object reference counts. 337//===----------------------------------------------------------------------===// 338 339typedef llvm::ImmutableMap<SymbolRef, RefVal> RefBindings; 340 341namespace clang { 342namespace ento { 343template<> 344struct ProgramStateTrait<RefBindings> 345 : public ProgramStatePartialTrait<RefBindings> { 346 static void *GDMIndex() { 347 static int RefBIndex = 0; 348 return &RefBIndex; 349 } 350}; 351} 352} 353 354//===----------------------------------------------------------------------===// 355// Function/Method behavior summaries. 356//===----------------------------------------------------------------------===// 357 358namespace { 359class RetainSummary { 360 /// Args - a map of (index, ArgEffect) pairs, where index 361 /// specifies the argument (starting from 0). This can be sparsely 362 /// populated; arguments with no entry in Args use 'DefaultArgEffect'. 363 ArgEffects Args; 364 365 /// DefaultArgEffect - The default ArgEffect to apply to arguments that 366 /// do not have an entry in Args. 367 ArgEffect DefaultArgEffect; 368 369 /// Receiver - If this summary applies to an Objective-C message expression, 370 /// this is the effect applied to the state of the receiver. 371 ArgEffect Receiver; 372 373 /// Ret - The effect on the return value. Used to indicate if the 374 /// function/method call returns a new tracked symbol. 375 RetEffect Ret; 376 377public: 378 RetainSummary(ArgEffects A, RetEffect R, ArgEffect defaultEff, 379 ArgEffect ReceiverEff) 380 : Args(A), DefaultArgEffect(defaultEff), Receiver(ReceiverEff), Ret(R) {} 381 382 /// getArg - Return the argument effect on the argument specified by 383 /// idx (starting from 0). 384 ArgEffect getArg(unsigned idx) const { 385 if (const ArgEffect *AE = Args.lookup(idx)) 386 return *AE; 387 388 return DefaultArgEffect; 389 } 390 391 void addArg(ArgEffects::Factory &af, unsigned idx, ArgEffect e) { 392 Args = af.add(Args, idx, e); 393 } 394 395 /// setDefaultArgEffect - Set the default argument effect. 396 void setDefaultArgEffect(ArgEffect E) { 397 DefaultArgEffect = E; 398 } 399 400 /// getRetEffect - Returns the effect on the return value of the call. 401 RetEffect getRetEffect() const { return Ret; } 402 403 /// setRetEffect - Set the effect of the return value of the call. 404 void setRetEffect(RetEffect E) { Ret = E; } 405 406 407 /// Sets the effect on the receiver of the message. 408 void setReceiverEffect(ArgEffect e) { Receiver = e; } 409 410 /// getReceiverEffect - Returns the effect on the receiver of the call. 411 /// This is only meaningful if the summary applies to an ObjCMessageExpr*. 412 ArgEffect getReceiverEffect() const { return Receiver; } 413 414 /// Test if two retain summaries are identical. Note that merely equivalent 415 /// summaries are not necessarily identical (for example, if an explicit 416 /// argument effect matches the default effect). 417 bool operator==(const RetainSummary &Other) const { 418 return Args == Other.Args && DefaultArgEffect == Other.DefaultArgEffect && 419 Receiver == Other.Receiver && Ret == Other.Ret; 420 } 421 422 /// Profile this summary for inclusion in a FoldingSet. 423 void Profile(llvm::FoldingSetNodeID& ID) const { 424 ID.Add(Args); 425 ID.Add(DefaultArgEffect); 426 ID.Add(Receiver); 427 ID.Add(Ret); 428 } 429 430 /// A retain summary is simple if it has no ArgEffects other than the default. 431 bool isSimple() const { 432 return Args.isEmpty(); 433 } 434}; 435} // end anonymous namespace 436 437//===----------------------------------------------------------------------===// 438// Data structures for constructing summaries. 439//===----------------------------------------------------------------------===// 440 441namespace { 442class ObjCSummaryKey { 443 IdentifierInfo* II; 444 Selector S; 445public: 446 ObjCSummaryKey(IdentifierInfo* ii, Selector s) 447 : II(ii), S(s) {} 448 449 ObjCSummaryKey(const ObjCInterfaceDecl *d, Selector s) 450 : II(d ? d->getIdentifier() : 0), S(s) {} 451 452 ObjCSummaryKey(const ObjCInterfaceDecl *d, IdentifierInfo *ii, Selector s) 453 : II(d ? d->getIdentifier() : ii), S(s) {} 454 455 ObjCSummaryKey(Selector s) 456 : II(0), S(s) {} 457 458 IdentifierInfo *getIdentifier() const { return II; } 459 Selector getSelector() const { return S; } 460}; 461} 462 463namespace llvm { 464template <> struct DenseMapInfo<ObjCSummaryKey> { 465 static inline ObjCSummaryKey getEmptyKey() { 466 return ObjCSummaryKey(DenseMapInfo<IdentifierInfo*>::getEmptyKey(), 467 DenseMapInfo<Selector>::getEmptyKey()); 468 } 469 470 static inline ObjCSummaryKey getTombstoneKey() { 471 return ObjCSummaryKey(DenseMapInfo<IdentifierInfo*>::getTombstoneKey(), 472 DenseMapInfo<Selector>::getTombstoneKey()); 473 } 474 475 static unsigned getHashValue(const ObjCSummaryKey &V) { 476 typedef std::pair<IdentifierInfo*, Selector> PairTy; 477 return DenseMapInfo<PairTy>::getHashValue(PairTy(V.getIdentifier(), 478 V.getSelector())); 479 } 480 481 static bool isEqual(const ObjCSummaryKey& LHS, const ObjCSummaryKey& RHS) { 482 return LHS.getIdentifier() == RHS.getIdentifier() && 483 LHS.getSelector() == RHS.getSelector(); 484 } 485 486}; 487template <> 488struct isPodLike<ObjCSummaryKey> { static const bool value = true; }; 489} // end llvm namespace 490 491namespace { 492class ObjCSummaryCache { 493 typedef llvm::DenseMap<ObjCSummaryKey, const RetainSummary *> MapTy; 494 MapTy M; 495public: 496 ObjCSummaryCache() {} 497 498 const RetainSummary * find(const ObjCInterfaceDecl *D, IdentifierInfo *ClsName, 499 Selector S) { 500 // Lookup the method using the decl for the class @interface. If we 501 // have no decl, lookup using the class name. 502 return D ? find(D, S) : find(ClsName, S); 503 } 504 505 const RetainSummary * find(const ObjCInterfaceDecl *D, Selector S) { 506 // Do a lookup with the (D,S) pair. If we find a match return 507 // the iterator. 508 ObjCSummaryKey K(D, S); 509 MapTy::iterator I = M.find(K); 510 511 if (I != M.end() || !D) 512 return I->second; 513 514 // Walk the super chain. If we find a hit with a parent, we'll end 515 // up returning that summary. We actually allow that key (null,S), as 516 // we cache summaries for the null ObjCInterfaceDecl* to allow us to 517 // generate initial summaries without having to worry about NSObject 518 // being declared. 519 // FIXME: We may change this at some point. 520 for (ObjCInterfaceDecl *C=D->getSuperClass() ;; C=C->getSuperClass()) { 521 if ((I = M.find(ObjCSummaryKey(C, S))) != M.end()) 522 break; 523 524 if (!C) 525 return NULL; 526 } 527 528 // Cache the summary with original key to make the next lookup faster 529 // and return the iterator. 530 const RetainSummary *Summ = I->second; 531 M[K] = Summ; 532 return Summ; 533 } 534 535 const RetainSummary *find(IdentifierInfo* II, Selector S) { 536 // FIXME: Class method lookup. Right now we dont' have a good way 537 // of going between IdentifierInfo* and the class hierarchy. 538 MapTy::iterator I = M.find(ObjCSummaryKey(II, S)); 539 540 if (I == M.end()) 541 I = M.find(ObjCSummaryKey(S)); 542 543 return I == M.end() ? NULL : I->second; 544 } 545 546 const RetainSummary *& operator[](ObjCSummaryKey K) { 547 return M[K]; 548 } 549 550 const RetainSummary *& operator[](Selector S) { 551 return M[ ObjCSummaryKey(S) ]; 552 } 553}; 554} // end anonymous namespace 555 556//===----------------------------------------------------------------------===// 557// Data structures for managing collections of summaries. 558//===----------------------------------------------------------------------===// 559 560namespace { 561class RetainSummaryManager { 562 563 //==-----------------------------------------------------------------==// 564 // Typedefs. 565 //==-----------------------------------------------------------------==// 566 567 typedef llvm::DenseMap<const FunctionDecl*, const RetainSummary *> 568 FuncSummariesTy; 569 570 typedef ObjCSummaryCache ObjCMethodSummariesTy; 571 572 typedef llvm::FoldingSetNodeWrapper<RetainSummary> CachedSummaryNode; 573 574 //==-----------------------------------------------------------------==// 575 // Data. 576 //==-----------------------------------------------------------------==// 577 578 /// Ctx - The ASTContext object for the analyzed ASTs. 579 ASTContext &Ctx; 580 581 /// GCEnabled - Records whether or not the analyzed code runs in GC mode. 582 const bool GCEnabled; 583 584 /// Records whether or not the analyzed code runs in ARC mode. 585 const bool ARCEnabled; 586 587 /// FuncSummaries - A map from FunctionDecls to summaries. 588 FuncSummariesTy FuncSummaries; 589 590 /// ObjCClassMethodSummaries - A map from selectors (for instance methods) 591 /// to summaries. 592 ObjCMethodSummariesTy ObjCClassMethodSummaries; 593 594 /// ObjCMethodSummaries - A map from selectors to summaries. 595 ObjCMethodSummariesTy ObjCMethodSummaries; 596 597 /// BPAlloc - A BumpPtrAllocator used for allocating summaries, ArgEffects, 598 /// and all other data used by the checker. 599 llvm::BumpPtrAllocator BPAlloc; 600 601 /// AF - A factory for ArgEffects objects. 602 ArgEffects::Factory AF; 603 604 /// ScratchArgs - A holding buffer for construct ArgEffects. 605 ArgEffects ScratchArgs; 606 607 /// ObjCAllocRetE - Default return effect for methods returning Objective-C 608 /// objects. 609 RetEffect ObjCAllocRetE; 610 611 /// ObjCInitRetE - Default return effect for init methods returning 612 /// Objective-C objects. 613 RetEffect ObjCInitRetE; 614 615 /// SimpleSummaries - Used for uniquing summaries that don't have special 616 /// effects. 617 llvm::FoldingSet<CachedSummaryNode> SimpleSummaries; 618 619 //==-----------------------------------------------------------------==// 620 // Methods. 621 //==-----------------------------------------------------------------==// 622 623 /// getArgEffects - Returns a persistent ArgEffects object based on the 624 /// data in ScratchArgs. 625 ArgEffects getArgEffects(); 626 627 enum UnaryFuncKind { cfretain, cfrelease, cfmakecollectable }; 628 629public: 630 RetEffect getObjAllocRetEffect() const { return ObjCAllocRetE; } 631 632 const RetainSummary *getUnarySummary(const FunctionType* FT, 633 UnaryFuncKind func); 634 635 const RetainSummary *getCFSummaryCreateRule(const FunctionDecl *FD); 636 const RetainSummary *getCFSummaryGetRule(const FunctionDecl *FD); 637 const RetainSummary *getCFCreateGetRuleSummary(const FunctionDecl *FD); 638 639 const RetainSummary *getPersistentSummary(const RetainSummary &OldSumm); 640 641 const RetainSummary *getPersistentSummary(RetEffect RetEff, 642 ArgEffect ReceiverEff = DoNothing, 643 ArgEffect DefaultEff = MayEscape) { 644 RetainSummary Summ(getArgEffects(), RetEff, DefaultEff, ReceiverEff); 645 return getPersistentSummary(Summ); 646 } 647 648 const RetainSummary *getDoNothingSummary() { 649 return getPersistentSummary(RetEffect::MakeNoRet(), DoNothing, DoNothing); 650 } 651 652 const RetainSummary *getDefaultSummary() { 653 return getPersistentSummary(RetEffect::MakeNoRet(), 654 DoNothing, MayEscape); 655 } 656 657 const RetainSummary *getPersistentStopSummary() { 658 return getPersistentSummary(RetEffect::MakeNoRet(), 659 StopTracking, StopTracking); 660 } 661 662 void InitializeClassMethodSummaries(); 663 void InitializeMethodSummaries(); 664private: 665 void addNSObjectClsMethSummary(Selector S, const RetainSummary *Summ) { 666 ObjCClassMethodSummaries[S] = Summ; 667 } 668 669 void addNSObjectMethSummary(Selector S, const RetainSummary *Summ) { 670 ObjCMethodSummaries[S] = Summ; 671 } 672 673 void addClassMethSummary(const char* Cls, const char* name, 674 const RetainSummary *Summ, bool isNullary = true) { 675 IdentifierInfo* ClsII = &Ctx.Idents.get(Cls); 676 Selector S = isNullary ? GetNullarySelector(name, Ctx) 677 : GetUnarySelector(name, Ctx); 678 ObjCClassMethodSummaries[ObjCSummaryKey(ClsII, S)] = Summ; 679 } 680 681 void addInstMethSummary(const char* Cls, const char* nullaryName, 682 const RetainSummary *Summ) { 683 IdentifierInfo* ClsII = &Ctx.Idents.get(Cls); 684 Selector S = GetNullarySelector(nullaryName, Ctx); 685 ObjCMethodSummaries[ObjCSummaryKey(ClsII, S)] = Summ; 686 } 687 688 Selector generateSelector(va_list argp) { 689 SmallVector<IdentifierInfo*, 10> II; 690 691 while (const char* s = va_arg(argp, const char*)) 692 II.push_back(&Ctx.Idents.get(s)); 693 694 return Ctx.Selectors.getSelector(II.size(), &II[0]); 695 } 696 697 void addMethodSummary(IdentifierInfo *ClsII, ObjCMethodSummariesTy& Summaries, 698 const RetainSummary * Summ, va_list argp) { 699 Selector S = generateSelector(argp); 700 Summaries[ObjCSummaryKey(ClsII, S)] = Summ; 701 } 702 703 void addInstMethSummary(const char* Cls, const RetainSummary * Summ, ...) { 704 va_list argp; 705 va_start(argp, Summ); 706 addMethodSummary(&Ctx.Idents.get(Cls), ObjCMethodSummaries, Summ, argp); 707 va_end(argp); 708 } 709 710 void addClsMethSummary(const char* Cls, const RetainSummary * Summ, ...) { 711 va_list argp; 712 va_start(argp, Summ); 713 addMethodSummary(&Ctx.Idents.get(Cls),ObjCClassMethodSummaries, Summ, argp); 714 va_end(argp); 715 } 716 717 void addClsMethSummary(IdentifierInfo *II, const RetainSummary * Summ, ...) { 718 va_list argp; 719 va_start(argp, Summ); 720 addMethodSummary(II, ObjCClassMethodSummaries, Summ, argp); 721 va_end(argp); 722 } 723 724public: 725 726 RetainSummaryManager(ASTContext &ctx, bool gcenabled, bool usesARC) 727 : Ctx(ctx), 728 GCEnabled(gcenabled), 729 ARCEnabled(usesARC), 730 AF(BPAlloc), ScratchArgs(AF.getEmptyMap()), 731 ObjCAllocRetE(gcenabled 732 ? RetEffect::MakeGCNotOwned() 733 : (usesARC ? RetEffect::MakeARCNotOwned() 734 : RetEffect::MakeOwned(RetEffect::ObjC, true))), 735 ObjCInitRetE(gcenabled 736 ? RetEffect::MakeGCNotOwned() 737 : (usesARC ? RetEffect::MakeARCNotOwned() 738 : RetEffect::MakeOwnedWhenTrackedReceiver())) { 739 InitializeClassMethodSummaries(); 740 InitializeMethodSummaries(); 741 } 742 743 const RetainSummary *getSummary(const FunctionDecl *FD, 744 const CallOrObjCMessage *CME = 0); 745 746 const RetainSummary *getMethodSummary(Selector S, IdentifierInfo *ClsName, 747 const ObjCInterfaceDecl *ID, 748 const ObjCMethodDecl *MD, 749 QualType RetTy, 750 ObjCMethodSummariesTy &CachedSummaries); 751 752 const RetainSummary *getInstanceMethodSummary(const ObjCMessage &msg, 753 ProgramStateRef state, 754 const LocationContext *LC); 755 756 const RetainSummary *getInstanceMethodSummary(const ObjCMessage &msg, 757 const ObjCInterfaceDecl *ID) { 758 return getMethodSummary(msg.getSelector(), 0, ID, msg.getMethodDecl(), 759 msg.getType(Ctx), ObjCMethodSummaries); 760 } 761 762 const RetainSummary *getClassMethodSummary(const ObjCMessage &msg) { 763 const ObjCInterfaceDecl *Class = 0; 764 if (!msg.isInstanceMessage()) 765 Class = msg.getReceiverInterface(); 766 767 return getMethodSummary(msg.getSelector(), Class->getIdentifier(), 768 Class, msg.getMethodDecl(), msg.getType(Ctx), 769 ObjCClassMethodSummaries); 770 } 771 772 /// getMethodSummary - This version of getMethodSummary is used to query 773 /// the summary for the current method being analyzed. 774 const RetainSummary *getMethodSummary(const ObjCMethodDecl *MD) { 775 // FIXME: Eventually this should be unneeded. 776 const ObjCInterfaceDecl *ID = MD->getClassInterface(); 777 Selector S = MD->getSelector(); 778 IdentifierInfo *ClsName = ID->getIdentifier(); 779 QualType ResultTy = MD->getResultType(); 780 781 ObjCMethodSummariesTy *CachedSummaries; 782 if (MD->isInstanceMethod()) 783 CachedSummaries = &ObjCMethodSummaries; 784 else 785 CachedSummaries = &ObjCClassMethodSummaries; 786 787 return getMethodSummary(S, ClsName, ID, MD, ResultTy, *CachedSummaries); 788 } 789 790 const RetainSummary *getStandardMethodSummary(const ObjCMethodDecl *MD, 791 Selector S, QualType RetTy); 792 793 void updateSummaryFromAnnotations(const RetainSummary *&Summ, 794 const ObjCMethodDecl *MD); 795 796 void updateSummaryFromAnnotations(const RetainSummary *&Summ, 797 const FunctionDecl *FD); 798 799 bool isGCEnabled() const { return GCEnabled; } 800 801 bool isARCEnabled() const { return ARCEnabled; } 802 803 bool isARCorGCEnabled() const { return GCEnabled || ARCEnabled; } 804}; 805 806// Used to avoid allocating long-term (BPAlloc'd) memory for default retain 807// summaries. If a function or method looks like it has a default summary, but 808// it has annotations, the annotations are added to the stack-based template 809// and then copied into managed memory. 810class RetainSummaryTemplate { 811 RetainSummaryManager &Manager; 812 const RetainSummary *&RealSummary; 813 RetainSummary ScratchSummary; 814 bool Accessed; 815public: 816 RetainSummaryTemplate(const RetainSummary *&real, const RetainSummary &base, 817 RetainSummaryManager &mgr) 818 : Manager(mgr), RealSummary(real), ScratchSummary(real ? *real : base), 819 Accessed(false) {} 820 821 ~RetainSummaryTemplate() { 822 if (Accessed) 823 RealSummary = Manager.getPersistentSummary(ScratchSummary); 824 } 825 826 RetainSummary &operator*() { 827 Accessed = true; 828 return ScratchSummary; 829 } 830 831 RetainSummary *operator->() { 832 Accessed = true; 833 return &ScratchSummary; 834 } 835}; 836 837} // end anonymous namespace 838 839//===----------------------------------------------------------------------===// 840// Implementation of checker data structures. 841//===----------------------------------------------------------------------===// 842 843ArgEffects RetainSummaryManager::getArgEffects() { 844 ArgEffects AE = ScratchArgs; 845 ScratchArgs = AF.getEmptyMap(); 846 return AE; 847} 848 849const RetainSummary * 850RetainSummaryManager::getPersistentSummary(const RetainSummary &OldSumm) { 851 // Unique "simple" summaries -- those without ArgEffects. 852 if (OldSumm.isSimple()) { 853 llvm::FoldingSetNodeID ID; 854 OldSumm.Profile(ID); 855 856 void *Pos; 857 CachedSummaryNode *N = SimpleSummaries.FindNodeOrInsertPos(ID, Pos); 858 859 if (!N) { 860 N = (CachedSummaryNode *) BPAlloc.Allocate<CachedSummaryNode>(); 861 new (N) CachedSummaryNode(OldSumm); 862 SimpleSummaries.InsertNode(N, Pos); 863 } 864 865 return &N->getValue(); 866 } 867 868 RetainSummary *Summ = (RetainSummary *) BPAlloc.Allocate<RetainSummary>(); 869 new (Summ) RetainSummary(OldSumm); 870 return Summ; 871} 872 873//===----------------------------------------------------------------------===// 874// Summary creation for functions (largely uses of Core Foundation). 875//===----------------------------------------------------------------------===// 876 877static bool isRetain(const FunctionDecl *FD, StringRef FName) { 878 return FName.endswith("Retain"); 879} 880 881static bool isRelease(const FunctionDecl *FD, StringRef FName) { 882 return FName.endswith("Release"); 883} 884 885static bool isMakeCollectable(const FunctionDecl *FD, StringRef FName) { 886 // FIXME: Remove FunctionDecl parameter. 887 // FIXME: Is it really okay if MakeCollectable isn't a suffix? 888 return FName.find("MakeCollectable") != StringRef::npos; 889} 890 891const RetainSummary * 892RetainSummaryManager::getSummary(const FunctionDecl *FD, 893 const CallOrObjCMessage *CME) { 894 // Look up a summary in our cache of FunctionDecls -> Summaries. 895 FuncSummariesTy::iterator I = FuncSummaries.find(FD); 896 if (I != FuncSummaries.end()) 897 return I->second; 898 899 // No summary? Generate one. 900 const RetainSummary *S = 0; 901 902 do { 903 // We generate "stop" summaries for implicitly defined functions. 904 if (FD->isImplicit()) { 905 S = getPersistentStopSummary(); 906 break; 907 } 908 // For C++ methods, generate an implicit "stop" summary as well. We 909 // can relax this once we have a clear policy for C++ methods and 910 // ownership attributes. 911 if (isa<CXXMethodDecl>(FD)) { 912 S = getPersistentStopSummary(); 913 break; 914 } 915 916 // [PR 3337] Use 'getAs<FunctionType>' to strip away any typedefs on the 917 // function's type. 918 const FunctionType* FT = FD->getType()->getAs<FunctionType>(); 919 const IdentifierInfo *II = FD->getIdentifier(); 920 if (!II) 921 break; 922 923 StringRef FName = II->getName(); 924 925 // Strip away preceding '_'. Doing this here will effect all the checks 926 // down below. 927 FName = FName.substr(FName.find_first_not_of('_')); 928 929 // Inspect the result type. 930 QualType RetTy = FT->getResultType(); 931 932 // FIXME: This should all be refactored into a chain of "summary lookup" 933 // filters. 934 assert(ScratchArgs.isEmpty()); 935 936 if (FName == "pthread_create" || FName == "pthread_setspecific") { 937 // Part of: <rdar://problem/7299394> and <rdar://problem/11282706>. 938 // This will be addressed better with IPA. 939 S = getPersistentStopSummary(); 940 } else if (FName == "NSMakeCollectable") { 941 // Handle: id NSMakeCollectable(CFTypeRef) 942 S = (RetTy->isObjCIdType()) 943 ? getUnarySummary(FT, cfmakecollectable) 944 : getPersistentStopSummary(); 945 } else if (FName == "IOBSDNameMatching" || 946 FName == "IOServiceMatching" || 947 FName == "IOServiceNameMatching" || 948 FName == "IORegistryEntrySearchCFProperty" || 949 FName == "IORegistryEntryIDMatching" || 950 FName == "IOOpenFirmwarePathMatching") { 951 // Part of <rdar://problem/6961230>. (IOKit) 952 // This should be addressed using a API table. 953 S = getPersistentSummary(RetEffect::MakeOwned(RetEffect::CF, true), 954 DoNothing, DoNothing); 955 } else if (FName == "IOServiceGetMatchingService" || 956 FName == "IOServiceGetMatchingServices") { 957 // FIXES: <rdar://problem/6326900> 958 // This should be addressed using a API table. This strcmp is also 959 // a little gross, but there is no need to super optimize here. 960 ScratchArgs = AF.add(ScratchArgs, 1, DecRef); 961 S = getPersistentSummary(RetEffect::MakeNoRet(), DoNothing, DoNothing); 962 } else if (FName == "IOServiceAddNotification" || 963 FName == "IOServiceAddMatchingNotification") { 964 // Part of <rdar://problem/6961230>. (IOKit) 965 // This should be addressed using a API table. 966 ScratchArgs = AF.add(ScratchArgs, 2, DecRef); 967 S = getPersistentSummary(RetEffect::MakeNoRet(), DoNothing, DoNothing); 968 } else if (FName == "CVPixelBufferCreateWithBytes") { 969 // FIXES: <rdar://problem/7283567> 970 // Eventually this can be improved by recognizing that the pixel 971 // buffer passed to CVPixelBufferCreateWithBytes is released via 972 // a callback and doing full IPA to make sure this is done correctly. 973 // FIXME: This function has an out parameter that returns an 974 // allocated object. 975 ScratchArgs = AF.add(ScratchArgs, 7, StopTracking); 976 S = getPersistentSummary(RetEffect::MakeNoRet(), DoNothing, DoNothing); 977 } else if (FName == "CGBitmapContextCreateWithData") { 978 // FIXES: <rdar://problem/7358899> 979 // Eventually this can be improved by recognizing that 'releaseInfo' 980 // passed to CGBitmapContextCreateWithData is released via 981 // a callback and doing full IPA to make sure this is done correctly. 982 ScratchArgs = AF.add(ScratchArgs, 8, StopTracking); 983 S = getPersistentSummary(RetEffect::MakeOwned(RetEffect::CF, true), 984 DoNothing, DoNothing); 985 } else if (FName == "CVPixelBufferCreateWithPlanarBytes") { 986 // FIXES: <rdar://problem/7283567> 987 // Eventually this can be improved by recognizing that the pixel 988 // buffer passed to CVPixelBufferCreateWithPlanarBytes is released 989 // via a callback and doing full IPA to make sure this is done 990 // correctly. 991 ScratchArgs = AF.add(ScratchArgs, 12, StopTracking); 992 S = getPersistentSummary(RetEffect::MakeNoRet(), DoNothing, DoNothing); 993 } else if (FName == "dispatch_set_context") { 994 // <rdar://problem/11059275> - The analyzer currently doesn't have 995 // a good way to reason about the finalizer function for libdispatch. 996 // If we pass a context object that is memory managed, stop tracking it. 997 // FIXME: this hack should possibly go away once we can handle 998 // libdispatch finalizers. 999 ScratchArgs = AF.add(ScratchArgs, 1, StopTracking); 1000 S = getPersistentSummary(RetEffect::MakeNoRet(), DoNothing, DoNothing); 1001 } else if (FName.startswith("NSLog")) { 1002 S = getDoNothingSummary(); 1003 } else if (FName.startswith("NS") && 1004 (FName.find("Insert") != StringRef::npos)) { 1005 // Whitelist NSXXInsertXX, for example NSMapInsertIfAbsent, since they can 1006 // be deallocated by NSMapRemove. (radar://11152419) 1007 ScratchArgs = AF.add(ScratchArgs, 1, StopTracking); 1008 ScratchArgs = AF.add(ScratchArgs, 2, StopTracking); 1009 S = getPersistentSummary(RetEffect::MakeNoRet(), DoNothing, DoNothing); 1010 } else if (CME && CME->hasNonZeroCallbackArg()) { 1011 // Allow objects to escape through callbacks. radar://10973977 1012 S = getPersistentStopSummary(); 1013 } 1014 1015 // Did we get a summary? 1016 if (S) 1017 break; 1018 1019 // Enable this code once the semantics of NSDeallocateObject are resolved 1020 // for GC. <rdar://problem/6619988> 1021#if 0 1022 // Handle: NSDeallocateObject(id anObject); 1023 // This method does allow 'nil' (although we don't check it now). 1024 if (strcmp(FName, "NSDeallocateObject") == 0) { 1025 return RetTy == Ctx.VoidTy 1026 ? getPersistentSummary(RetEffect::MakeNoRet(), DoNothing, Dealloc) 1027 : getPersistentStopSummary(); 1028 } 1029#endif 1030 1031 if (RetTy->isPointerType()) { 1032 // For CoreFoundation ('CF') types. 1033 if (cocoa::isRefType(RetTy, "CF", FName)) { 1034 if (isRetain(FD, FName)) 1035 S = getUnarySummary(FT, cfretain); 1036 else if (isMakeCollectable(FD, FName)) 1037 S = getUnarySummary(FT, cfmakecollectable); 1038 else 1039 S = getCFCreateGetRuleSummary(FD); 1040 1041 break; 1042 } 1043 1044 // For CoreGraphics ('CG') types. 1045 if (cocoa::isRefType(RetTy, "CG", FName)) { 1046 if (isRetain(FD, FName)) 1047 S = getUnarySummary(FT, cfretain); 1048 else 1049 S = getCFCreateGetRuleSummary(FD); 1050 1051 break; 1052 } 1053 1054 // For the Disk Arbitration API (DiskArbitration/DADisk.h) 1055 if (cocoa::isRefType(RetTy, "DADisk") || 1056 cocoa::isRefType(RetTy, "DADissenter") || 1057 cocoa::isRefType(RetTy, "DASessionRef")) { 1058 S = getCFCreateGetRuleSummary(FD); 1059 break; 1060 } 1061 1062 break; 1063 } 1064 1065 // Check for release functions, the only kind of functions that we care 1066 // about that don't return a pointer type. 1067 if (FName[0] == 'C' && (FName[1] == 'F' || FName[1] == 'G')) { 1068 // Test for 'CGCF'. 1069 FName = FName.substr(FName.startswith("CGCF") ? 4 : 2); 1070 1071 if (isRelease(FD, FName)) 1072 S = getUnarySummary(FT, cfrelease); 1073 else { 1074 assert (ScratchArgs.isEmpty()); 1075 // Remaining CoreFoundation and CoreGraphics functions. 1076 // We use to assume that they all strictly followed the ownership idiom 1077 // and that ownership cannot be transferred. While this is technically 1078 // correct, many methods allow a tracked object to escape. For example: 1079 // 1080 // CFMutableDictionaryRef x = CFDictionaryCreateMutable(...); 1081 // CFDictionaryAddValue(y, key, x); 1082 // CFRelease(x); 1083 // ... it is okay to use 'x' since 'y' has a reference to it 1084 // 1085 // We handle this and similar cases with the follow heuristic. If the 1086 // function name contains "InsertValue", "SetValue", "AddValue", 1087 // "AppendValue", or "SetAttribute", then we assume that arguments may 1088 // "escape." This means that something else holds on to the object, 1089 // allowing it be used even after its local retain count drops to 0. 1090 ArgEffect E = (StrInStrNoCase(FName, "InsertValue") != StringRef::npos|| 1091 StrInStrNoCase(FName, "AddValue") != StringRef::npos || 1092 StrInStrNoCase(FName, "SetValue") != StringRef::npos || 1093 StrInStrNoCase(FName, "AppendValue") != StringRef::npos|| 1094 StrInStrNoCase(FName, "SetAttribute") != StringRef::npos) 1095 ? MayEscape : DoNothing; 1096 1097 S = getPersistentSummary(RetEffect::MakeNoRet(), DoNothing, E); 1098 } 1099 } 1100 } 1101 while (0); 1102 1103 // Annotations override defaults. 1104 updateSummaryFromAnnotations(S, FD); 1105 1106 FuncSummaries[FD] = S; 1107 return S; 1108} 1109 1110const RetainSummary * 1111RetainSummaryManager::getCFCreateGetRuleSummary(const FunctionDecl *FD) { 1112 if (coreFoundation::followsCreateRule(FD)) 1113 return getCFSummaryCreateRule(FD); 1114 1115 return getCFSummaryGetRule(FD); 1116} 1117 1118const RetainSummary * 1119RetainSummaryManager::getUnarySummary(const FunctionType* FT, 1120 UnaryFuncKind func) { 1121 1122 // Sanity check that this is *really* a unary function. This can 1123 // happen if people do weird things. 1124 const FunctionProtoType* FTP = dyn_cast<FunctionProtoType>(FT); 1125 if (!FTP || FTP->getNumArgs() != 1) 1126 return getPersistentStopSummary(); 1127 1128 assert (ScratchArgs.isEmpty()); 1129 1130 ArgEffect Effect; 1131 switch (func) { 1132 case cfretain: Effect = IncRef; break; 1133 case cfrelease: Effect = DecRef; break; 1134 case cfmakecollectable: Effect = MakeCollectable; break; 1135 } 1136 1137 ScratchArgs = AF.add(ScratchArgs, 0, Effect); 1138 return getPersistentSummary(RetEffect::MakeNoRet(), DoNothing, DoNothing); 1139} 1140 1141const RetainSummary * 1142RetainSummaryManager::getCFSummaryCreateRule(const FunctionDecl *FD) { 1143 assert (ScratchArgs.isEmpty()); 1144 1145 return getPersistentSummary(RetEffect::MakeOwned(RetEffect::CF, true)); 1146} 1147 1148const RetainSummary * 1149RetainSummaryManager::getCFSummaryGetRule(const FunctionDecl *FD) { 1150 assert (ScratchArgs.isEmpty()); 1151 return getPersistentSummary(RetEffect::MakeNotOwned(RetEffect::CF), 1152 DoNothing, DoNothing); 1153} 1154 1155//===----------------------------------------------------------------------===// 1156// Summary creation for Selectors. 1157//===----------------------------------------------------------------------===// 1158 1159void 1160RetainSummaryManager::updateSummaryFromAnnotations(const RetainSummary *&Summ, 1161 const FunctionDecl *FD) { 1162 if (!FD) 1163 return; 1164 1165 RetainSummaryTemplate Template(Summ, *getDefaultSummary(), *this); 1166 1167 // Effects on the parameters. 1168 unsigned parm_idx = 0; 1169 for (FunctionDecl::param_const_iterator pi = FD->param_begin(), 1170 pe = FD->param_end(); pi != pe; ++pi, ++parm_idx) { 1171 const ParmVarDecl *pd = *pi; 1172 if (pd->getAttr<NSConsumedAttr>()) { 1173 if (!GCEnabled) { 1174 Template->addArg(AF, parm_idx, DecRef); 1175 } 1176 } else if (pd->getAttr<CFConsumedAttr>()) { 1177 Template->addArg(AF, parm_idx, DecRef); 1178 } 1179 } 1180 1181 QualType RetTy = FD->getResultType(); 1182 1183 // Determine if there is a special return effect for this method. 1184 if (cocoa::isCocoaObjectRef(RetTy)) { 1185 if (FD->getAttr<NSReturnsRetainedAttr>()) { 1186 Template->setRetEffect(ObjCAllocRetE); 1187 } 1188 else if (FD->getAttr<CFReturnsRetainedAttr>()) { 1189 Template->setRetEffect(RetEffect::MakeOwned(RetEffect::CF, true)); 1190 } 1191 else if (FD->getAttr<NSReturnsNotRetainedAttr>()) { 1192 Template->setRetEffect(RetEffect::MakeNotOwned(RetEffect::ObjC)); 1193 } 1194 else if (FD->getAttr<CFReturnsNotRetainedAttr>()) { 1195 Template->setRetEffect(RetEffect::MakeNotOwned(RetEffect::CF)); 1196 } 1197 } else if (RetTy->getAs<PointerType>()) { 1198 if (FD->getAttr<CFReturnsRetainedAttr>()) { 1199 Template->setRetEffect(RetEffect::MakeOwned(RetEffect::CF, true)); 1200 } 1201 else if (FD->getAttr<CFReturnsNotRetainedAttr>()) { 1202 Template->setRetEffect(RetEffect::MakeNotOwned(RetEffect::CF)); 1203 } 1204 } 1205} 1206 1207void 1208RetainSummaryManager::updateSummaryFromAnnotations(const RetainSummary *&Summ, 1209 const ObjCMethodDecl *MD) { 1210 if (!MD) 1211 return; 1212 1213 RetainSummaryTemplate Template(Summ, *getDefaultSummary(), *this); 1214 bool isTrackedLoc = false; 1215 1216 // Effects on the receiver. 1217 if (MD->getAttr<NSConsumesSelfAttr>()) { 1218 if (!GCEnabled) 1219 Template->setReceiverEffect(DecRefMsg); 1220 } 1221 1222 // Effects on the parameters. 1223 unsigned parm_idx = 0; 1224 for (ObjCMethodDecl::param_const_iterator 1225 pi=MD->param_begin(), pe=MD->param_end(); 1226 pi != pe; ++pi, ++parm_idx) { 1227 const ParmVarDecl *pd = *pi; 1228 if (pd->getAttr<NSConsumedAttr>()) { 1229 if (!GCEnabled) 1230 Template->addArg(AF, parm_idx, DecRef); 1231 } 1232 else if(pd->getAttr<CFConsumedAttr>()) { 1233 Template->addArg(AF, parm_idx, DecRef); 1234 } 1235 } 1236 1237 // Determine if there is a special return effect for this method. 1238 if (cocoa::isCocoaObjectRef(MD->getResultType())) { 1239 if (MD->getAttr<NSReturnsRetainedAttr>()) { 1240 Template->setRetEffect(ObjCAllocRetE); 1241 return; 1242 } 1243 if (MD->getAttr<NSReturnsNotRetainedAttr>()) { 1244 Template->setRetEffect(RetEffect::MakeNotOwned(RetEffect::ObjC)); 1245 return; 1246 } 1247 1248 isTrackedLoc = true; 1249 } else { 1250 isTrackedLoc = MD->getResultType()->getAs<PointerType>() != NULL; 1251 } 1252 1253 if (isTrackedLoc) { 1254 if (MD->getAttr<CFReturnsRetainedAttr>()) 1255 Template->setRetEffect(RetEffect::MakeOwned(RetEffect::CF, true)); 1256 else if (MD->getAttr<CFReturnsNotRetainedAttr>()) 1257 Template->setRetEffect(RetEffect::MakeNotOwned(RetEffect::CF)); 1258 } 1259} 1260 1261const RetainSummary * 1262RetainSummaryManager::getStandardMethodSummary(const ObjCMethodDecl *MD, 1263 Selector S, QualType RetTy) { 1264 1265 if (MD) { 1266 // Scan the method decl for 'void*' arguments. These should be treated 1267 // as 'StopTracking' because they are often used with delegates. 1268 // Delegates are a frequent form of false positives with the retain 1269 // count checker. 1270 unsigned i = 0; 1271 for (ObjCMethodDecl::param_const_iterator I = MD->param_begin(), 1272 E = MD->param_end(); I != E; ++I, ++i) 1273 if (const ParmVarDecl *PD = *I) { 1274 QualType Ty = Ctx.getCanonicalType(PD->getType()); 1275 if (Ty.getLocalUnqualifiedType() == Ctx.VoidPtrTy) 1276 ScratchArgs = AF.add(ScratchArgs, i, StopTracking); 1277 } 1278 } 1279 1280 // Any special effects? 1281 ArgEffect ReceiverEff = DoNothing; 1282 RetEffect ResultEff = RetEffect::MakeNoRet(); 1283 1284 // Check the method family, and apply any default annotations. 1285 switch (MD ? MD->getMethodFamily() : S.getMethodFamily()) { 1286 case OMF_None: 1287 case OMF_performSelector: 1288 // Assume all Objective-C methods follow Cocoa Memory Management rules. 1289 // FIXME: Does the non-threaded performSelector family really belong here? 1290 // The selector could be, say, @selector(copy). 1291 if (cocoa::isCocoaObjectRef(RetTy)) 1292 ResultEff = RetEffect::MakeNotOwned(RetEffect::ObjC); 1293 else if (coreFoundation::isCFObjectRef(RetTy)) { 1294 // ObjCMethodDecl currently doesn't consider CF objects as valid return 1295 // values for alloc, new, copy, or mutableCopy, so we have to 1296 // double-check with the selector. This is ugly, but there aren't that 1297 // many Objective-C methods that return CF objects, right? 1298 if (MD) { 1299 switch (S.getMethodFamily()) { 1300 case OMF_alloc: 1301 case OMF_new: 1302 case OMF_copy: 1303 case OMF_mutableCopy: 1304 ResultEff = RetEffect::MakeOwned(RetEffect::CF, true); 1305 break; 1306 default: 1307 ResultEff = RetEffect::MakeNotOwned(RetEffect::CF); 1308 break; 1309 } 1310 } else { 1311 ResultEff = RetEffect::MakeNotOwned(RetEffect::CF); 1312 } 1313 } 1314 break; 1315 case OMF_init: 1316 ResultEff = ObjCInitRetE; 1317 ReceiverEff = DecRefMsg; 1318 break; 1319 case OMF_alloc: 1320 case OMF_new: 1321 case OMF_copy: 1322 case OMF_mutableCopy: 1323 if (cocoa::isCocoaObjectRef(RetTy)) 1324 ResultEff = ObjCAllocRetE; 1325 else if (coreFoundation::isCFObjectRef(RetTy)) 1326 ResultEff = RetEffect::MakeOwned(RetEffect::CF, true); 1327 break; 1328 case OMF_autorelease: 1329 ReceiverEff = Autorelease; 1330 break; 1331 case OMF_retain: 1332 ReceiverEff = IncRefMsg; 1333 break; 1334 case OMF_release: 1335 ReceiverEff = DecRefMsg; 1336 break; 1337 case OMF_dealloc: 1338 ReceiverEff = Dealloc; 1339 break; 1340 case OMF_self: 1341 // -self is handled specially by the ExprEngine to propagate the receiver. 1342 break; 1343 case OMF_retainCount: 1344 case OMF_finalize: 1345 // These methods don't return objects. 1346 break; 1347 } 1348 1349 // If one of the arguments in the selector has the keyword 'delegate' we 1350 // should stop tracking the reference count for the receiver. This is 1351 // because the reference count is quite possibly handled by a delegate 1352 // method. 1353 if (S.isKeywordSelector()) { 1354 for (unsigned i = 0, e = S.getNumArgs(); i != e; ++i) { 1355 StringRef Slot = S.getNameForSlot(i); 1356 if (Slot.substr(Slot.size() - 8).equals_lower("delegate")) { 1357 if (ResultEff == ObjCInitRetE) 1358 ResultEff = RetEffect::MakeNoRet(); 1359 else 1360 ReceiverEff = StopTracking; 1361 } 1362 } 1363 } 1364 1365 if (ScratchArgs.isEmpty() && ReceiverEff == DoNothing && 1366 ResultEff.getKind() == RetEffect::NoRet) 1367 return getDefaultSummary(); 1368 1369 return getPersistentSummary(ResultEff, ReceiverEff, MayEscape); 1370} 1371 1372const RetainSummary * 1373RetainSummaryManager::getInstanceMethodSummary(const ObjCMessage &msg, 1374 ProgramStateRef state, 1375 const LocationContext *LC) { 1376 1377 // We need the type-information of the tracked receiver object 1378 // Retrieve it from the state. 1379 const Expr *Receiver = msg.getInstanceReceiver(); 1380 const ObjCInterfaceDecl *ID = 0; 1381 1382 // FIXME: Is this really working as expected? There are cases where 1383 // we just use the 'ID' from the message expression. 1384 SVal receiverV; 1385 1386 if (Receiver) { 1387 receiverV = state->getSValAsScalarOrLoc(Receiver, LC); 1388 1389 // FIXME: Eventually replace the use of state->get<RefBindings> with 1390 // a generic API for reasoning about the Objective-C types of symbolic 1391 // objects. 1392 if (SymbolRef Sym = receiverV.getAsLocSymbol()) 1393 if (const RefVal *T = state->get<RefBindings>(Sym)) 1394 if (const ObjCObjectPointerType* PT = 1395 T->getType()->getAs<ObjCObjectPointerType>()) 1396 ID = PT->getInterfaceDecl(); 1397 1398 // FIXME: this is a hack. This may or may not be the actual method 1399 // that is called. 1400 if (!ID) { 1401 if (const ObjCObjectPointerType *PT = 1402 Receiver->getType()->getAs<ObjCObjectPointerType>()) 1403 ID = PT->getInterfaceDecl(); 1404 } 1405 } else { 1406 // FIXME: Hack for 'super'. 1407 ID = msg.getReceiverInterface(); 1408 } 1409 1410 // FIXME: The receiver could be a reference to a class, meaning that 1411 // we should use the class method. 1412 return getInstanceMethodSummary(msg, ID); 1413} 1414 1415const RetainSummary * 1416RetainSummaryManager::getMethodSummary(Selector S, IdentifierInfo *ClsName, 1417 const ObjCInterfaceDecl *ID, 1418 const ObjCMethodDecl *MD, QualType RetTy, 1419 ObjCMethodSummariesTy &CachedSummaries) { 1420 1421 // Look up a summary in our summary cache. 1422 const RetainSummary *Summ = CachedSummaries.find(ID, ClsName, S); 1423 1424 if (!Summ) { 1425 Summ = getStandardMethodSummary(MD, S, RetTy); 1426 1427 // Annotations override defaults. 1428 updateSummaryFromAnnotations(Summ, MD); 1429 1430 // Memoize the summary. 1431 CachedSummaries[ObjCSummaryKey(ID, ClsName, S)] = Summ; 1432 } 1433 1434 return Summ; 1435} 1436 1437void RetainSummaryManager::InitializeClassMethodSummaries() { 1438 assert(ScratchArgs.isEmpty()); 1439 // Create the [NSAssertionHandler currentHander] summary. 1440 addClassMethSummary("NSAssertionHandler", "currentHandler", 1441 getPersistentSummary(RetEffect::MakeNotOwned(RetEffect::ObjC))); 1442 1443 // Create the [NSAutoreleasePool addObject:] summary. 1444 ScratchArgs = AF.add(ScratchArgs, 0, Autorelease); 1445 addClassMethSummary("NSAutoreleasePool", "addObject", 1446 getPersistentSummary(RetEffect::MakeNoRet(), 1447 DoNothing, Autorelease)); 1448 1449 // Create the summaries for [NSObject performSelector...]. We treat 1450 // these as 'stop tracking' for the arguments because they are often 1451 // used for delegates that can release the object. When we have better 1452 // inter-procedural analysis we can potentially do something better. This 1453 // workaround is to remove false positives. 1454 const RetainSummary *Summ = 1455 getPersistentSummary(RetEffect::MakeNoRet(), DoNothing, StopTracking); 1456 IdentifierInfo *NSObjectII = &Ctx.Idents.get("NSObject"); 1457 addClsMethSummary(NSObjectII, Summ, "performSelector", "withObject", 1458 "afterDelay", NULL); 1459 addClsMethSummary(NSObjectII, Summ, "performSelector", "withObject", 1460 "afterDelay", "inModes", NULL); 1461 addClsMethSummary(NSObjectII, Summ, "performSelectorOnMainThread", 1462 "withObject", "waitUntilDone", NULL); 1463 addClsMethSummary(NSObjectII, Summ, "performSelectorOnMainThread", 1464 "withObject", "waitUntilDone", "modes", NULL); 1465 addClsMethSummary(NSObjectII, Summ, "performSelector", "onThread", 1466 "withObject", "waitUntilDone", NULL); 1467 addClsMethSummary(NSObjectII, Summ, "performSelector", "onThread", 1468 "withObject", "waitUntilDone", "modes", NULL); 1469 addClsMethSummary(NSObjectII, Summ, "performSelectorInBackground", 1470 "withObject", NULL); 1471} 1472 1473void RetainSummaryManager::InitializeMethodSummaries() { 1474 1475 assert (ScratchArgs.isEmpty()); 1476 1477 // Create the "init" selector. It just acts as a pass-through for the 1478 // receiver. 1479 const RetainSummary *InitSumm = getPersistentSummary(ObjCInitRetE, DecRefMsg); 1480 addNSObjectMethSummary(GetNullarySelector("init", Ctx), InitSumm); 1481 1482 // awakeAfterUsingCoder: behaves basically like an 'init' method. It 1483 // claims the receiver and returns a retained object. 1484 addNSObjectMethSummary(GetUnarySelector("awakeAfterUsingCoder", Ctx), 1485 InitSumm); 1486 1487 // The next methods are allocators. 1488 const RetainSummary *AllocSumm = getPersistentSummary(ObjCAllocRetE); 1489 const RetainSummary *CFAllocSumm = 1490 getPersistentSummary(RetEffect::MakeOwned(RetEffect::CF, true)); 1491 1492 // Create the "retain" selector. 1493 RetEffect NoRet = RetEffect::MakeNoRet(); 1494 const RetainSummary *Summ = getPersistentSummary(NoRet, IncRefMsg); 1495 addNSObjectMethSummary(GetNullarySelector("retain", Ctx), Summ); 1496 1497 // Create the "release" selector. 1498 Summ = getPersistentSummary(NoRet, DecRefMsg); 1499 addNSObjectMethSummary(GetNullarySelector("release", Ctx), Summ); 1500 1501 // Create the "drain" selector. 1502 Summ = getPersistentSummary(NoRet, isGCEnabled() ? DoNothing : DecRef); 1503 addNSObjectMethSummary(GetNullarySelector("drain", Ctx), Summ); 1504 1505 // Create the -dealloc summary. 1506 Summ = getPersistentSummary(NoRet, Dealloc); 1507 addNSObjectMethSummary(GetNullarySelector("dealloc", Ctx), Summ); 1508 1509 // Create the "autorelease" selector. 1510 Summ = getPersistentSummary(NoRet, Autorelease); 1511 addNSObjectMethSummary(GetNullarySelector("autorelease", Ctx), Summ); 1512 1513 // Specially handle NSAutoreleasePool. 1514 addInstMethSummary("NSAutoreleasePool", "init", 1515 getPersistentSummary(NoRet, NewAutoreleasePool)); 1516 1517 // For NSWindow, allocated objects are (initially) self-owned. 1518 // FIXME: For now we opt for false negatives with NSWindow, as these objects 1519 // self-own themselves. However, they only do this once they are displayed. 1520 // Thus, we need to track an NSWindow's display status. 1521 // This is tracked in <rdar://problem/6062711>. 1522 // See also http://llvm.org/bugs/show_bug.cgi?id=3714. 1523 const RetainSummary *NoTrackYet = getPersistentSummary(RetEffect::MakeNoRet(), 1524 StopTracking, 1525 StopTracking); 1526 1527 addClassMethSummary("NSWindow", "alloc", NoTrackYet); 1528 1529#if 0 1530 addInstMethSummary("NSWindow", NoTrackYet, "initWithContentRect", 1531 "styleMask", "backing", "defer", NULL); 1532 1533 addInstMethSummary("NSWindow", NoTrackYet, "initWithContentRect", 1534 "styleMask", "backing", "defer", "screen", NULL); 1535#endif 1536 1537 // For NSPanel (which subclasses NSWindow), allocated objects are not 1538 // self-owned. 1539 // FIXME: For now we don't track NSPanels. object for the same reason 1540 // as for NSWindow objects. 1541 addClassMethSummary("NSPanel", "alloc", NoTrackYet); 1542 1543#if 0 1544 addInstMethSummary("NSPanel", NoTrackYet, "initWithContentRect", 1545 "styleMask", "backing", "defer", NULL); 1546 1547 addInstMethSummary("NSPanel", NoTrackYet, "initWithContentRect", 1548 "styleMask", "backing", "defer", "screen", NULL); 1549#endif 1550 1551 // Don't track allocated autorelease pools yet, as it is okay to prematurely 1552 // exit a method. 1553 addClassMethSummary("NSAutoreleasePool", "alloc", NoTrackYet); 1554 addClassMethSummary("NSAutoreleasePool", "allocWithZone", NoTrackYet, false); 1555 1556 // Create summaries QCRenderer/QCView -createSnapShotImageOfType: 1557 addInstMethSummary("QCRenderer", AllocSumm, 1558 "createSnapshotImageOfType", NULL); 1559 addInstMethSummary("QCView", AllocSumm, 1560 "createSnapshotImageOfType", NULL); 1561 1562 // Create summaries for CIContext, 'createCGImage' and 1563 // 'createCGLayerWithSize'. These objects are CF objects, and are not 1564 // automatically garbage collected. 1565 addInstMethSummary("CIContext", CFAllocSumm, 1566 "createCGImage", "fromRect", NULL); 1567 addInstMethSummary("CIContext", CFAllocSumm, 1568 "createCGImage", "fromRect", "format", "colorSpace", NULL); 1569 addInstMethSummary("CIContext", CFAllocSumm, "createCGLayerWithSize", 1570 "info", NULL); 1571} 1572 1573//===----------------------------------------------------------------------===// 1574// AutoreleaseBindings - State used to track objects in autorelease pools. 1575//===----------------------------------------------------------------------===// 1576 1577typedef llvm::ImmutableMap<SymbolRef, unsigned> ARCounts; 1578typedef llvm::ImmutableMap<SymbolRef, ARCounts> ARPoolContents; 1579typedef llvm::ImmutableList<SymbolRef> ARStack; 1580 1581static int AutoRCIndex = 0; 1582static int AutoRBIndex = 0; 1583 1584namespace { class AutoreleasePoolContents {}; } 1585namespace { class AutoreleaseStack {}; } 1586 1587namespace clang { 1588namespace ento { 1589template<> struct ProgramStateTrait<AutoreleaseStack> 1590 : public ProgramStatePartialTrait<ARStack> { 1591 static inline void *GDMIndex() { return &AutoRBIndex; } 1592}; 1593 1594template<> struct ProgramStateTrait<AutoreleasePoolContents> 1595 : public ProgramStatePartialTrait<ARPoolContents> { 1596 static inline void *GDMIndex() { return &AutoRCIndex; } 1597}; 1598} // end GR namespace 1599} // end clang namespace 1600 1601static SymbolRef GetCurrentAutoreleasePool(ProgramStateRef state) { 1602 ARStack stack = state->get<AutoreleaseStack>(); 1603 return stack.isEmpty() ? SymbolRef() : stack.getHead(); 1604} 1605 1606static ProgramStateRef 1607SendAutorelease(ProgramStateRef state, 1608 ARCounts::Factory &F, 1609 SymbolRef sym) { 1610 SymbolRef pool = GetCurrentAutoreleasePool(state); 1611 const ARCounts *cnts = state->get<AutoreleasePoolContents>(pool); 1612 ARCounts newCnts(0); 1613 1614 if (cnts) { 1615 const unsigned *cnt = (*cnts).lookup(sym); 1616 newCnts = F.add(*cnts, sym, cnt ? *cnt + 1 : 1); 1617 } 1618 else 1619 newCnts = F.add(F.getEmptyMap(), sym, 1); 1620 1621 return state->set<AutoreleasePoolContents>(pool, newCnts); 1622} 1623 1624//===----------------------------------------------------------------------===// 1625// Error reporting. 1626//===----------------------------------------------------------------------===// 1627namespace { 1628 typedef llvm::DenseMap<const ExplodedNode *, const RetainSummary *> 1629 SummaryLogTy; 1630 1631 //===-------------===// 1632 // Bug Descriptions. // 1633 //===-------------===// 1634 1635 class CFRefBug : public BugType { 1636 protected: 1637 CFRefBug(StringRef name) 1638 : BugType(name, categories::MemoryCoreFoundationObjectiveC) {} 1639 public: 1640 1641 // FIXME: Eventually remove. 1642 virtual const char *getDescription() const = 0; 1643 1644 virtual bool isLeak() const { return false; } 1645 }; 1646 1647 class UseAfterRelease : public CFRefBug { 1648 public: 1649 UseAfterRelease() : CFRefBug("Use-after-release") {} 1650 1651 const char *getDescription() const { 1652 return "Reference-counted object is used after it is released"; 1653 } 1654 }; 1655 1656 class BadRelease : public CFRefBug { 1657 public: 1658 BadRelease() : CFRefBug("Bad release") {} 1659 1660 const char *getDescription() const { 1661 return "Incorrect decrement of the reference count of an object that is " 1662 "not owned at this point by the caller"; 1663 } 1664 }; 1665 1666 class DeallocGC : public CFRefBug { 1667 public: 1668 DeallocGC() 1669 : CFRefBug("-dealloc called while using garbage collection") {} 1670 1671 const char *getDescription() const { 1672 return "-dealloc called while using garbage collection"; 1673 } 1674 }; 1675 1676 class DeallocNotOwned : public CFRefBug { 1677 public: 1678 DeallocNotOwned() 1679 : CFRefBug("-dealloc sent to non-exclusively owned object") {} 1680 1681 const char *getDescription() const { 1682 return "-dealloc sent to object that may be referenced elsewhere"; 1683 } 1684 }; 1685 1686 class OverAutorelease : public CFRefBug { 1687 public: 1688 OverAutorelease() 1689 : CFRefBug("Object sent -autorelease too many times") {} 1690 1691 const char *getDescription() const { 1692 return "Object sent -autorelease too many times"; 1693 } 1694 }; 1695 1696 class ReturnedNotOwnedForOwned : public CFRefBug { 1697 public: 1698 ReturnedNotOwnedForOwned() 1699 : CFRefBug("Method should return an owned object") {} 1700 1701 const char *getDescription() const { 1702 return "Object with a +0 retain count returned to caller where a +1 " 1703 "(owning) retain count is expected"; 1704 } 1705 }; 1706 1707 class Leak : public CFRefBug { 1708 public: 1709 Leak(StringRef name) 1710 : CFRefBug(name) { 1711 // Leaks should not be reported if they are post-dominated by a sink. 1712 setSuppressOnSink(true); 1713 } 1714 1715 const char *getDescription() const { return ""; } 1716 1717 bool isLeak() const { return true; } 1718 }; 1719 1720 //===---------===// 1721 // Bug Reports. // 1722 //===---------===// 1723 1724 class CFRefReportVisitor : public BugReporterVisitorImpl<CFRefReportVisitor> { 1725 protected: 1726 SymbolRef Sym; 1727 const SummaryLogTy &SummaryLog; 1728 bool GCEnabled; 1729 1730 public: 1731 CFRefReportVisitor(SymbolRef sym, bool gcEnabled, const SummaryLogTy &log) 1732 : Sym(sym), SummaryLog(log), GCEnabled(gcEnabled) {} 1733 1734 virtual void Profile(llvm::FoldingSetNodeID &ID) const { 1735 static int x = 0; 1736 ID.AddPointer(&x); 1737 ID.AddPointer(Sym); 1738 } 1739 1740 virtual PathDiagnosticPiece *VisitNode(const ExplodedNode *N, 1741 const ExplodedNode *PrevN, 1742 BugReporterContext &BRC, 1743 BugReport &BR); 1744 1745 virtual PathDiagnosticPiece *getEndPath(BugReporterContext &BRC, 1746 const ExplodedNode *N, 1747 BugReport &BR); 1748 }; 1749 1750 class CFRefLeakReportVisitor : public CFRefReportVisitor { 1751 public: 1752 CFRefLeakReportVisitor(SymbolRef sym, bool GCEnabled, 1753 const SummaryLogTy &log) 1754 : CFRefReportVisitor(sym, GCEnabled, log) {} 1755 1756 PathDiagnosticPiece *getEndPath(BugReporterContext &BRC, 1757 const ExplodedNode *N, 1758 BugReport &BR); 1759 1760 virtual BugReporterVisitor *clone() const { 1761 // The curiously-recurring template pattern only works for one level of 1762 // subclassing. Rather than make a new template base for 1763 // CFRefReportVisitor, we simply override clone() to do the right thing. 1764 // This could be trouble someday if BugReporterVisitorImpl is ever 1765 // used for something else besides a convenient implementation of clone(). 1766 return new CFRefLeakReportVisitor(*this); 1767 } 1768 }; 1769 1770 class CFRefReport : public BugReport { 1771 void addGCModeDescription(const LangOptions &LOpts, bool GCEnabled); 1772 1773 public: 1774 CFRefReport(CFRefBug &D, const LangOptions &LOpts, bool GCEnabled, 1775 const SummaryLogTy &Log, ExplodedNode *n, SymbolRef sym, 1776 bool registerVisitor = true) 1777 : BugReport(D, D.getDescription(), n) { 1778 if (registerVisitor) 1779 addVisitor(new CFRefReportVisitor(sym, GCEnabled, Log)); 1780 addGCModeDescription(LOpts, GCEnabled); 1781 } 1782 1783 CFRefReport(CFRefBug &D, const LangOptions &LOpts, bool GCEnabled, 1784 const SummaryLogTy &Log, ExplodedNode *n, SymbolRef sym, 1785 StringRef endText) 1786 : BugReport(D, D.getDescription(), endText, n) { 1787 addVisitor(new CFRefReportVisitor(sym, GCEnabled, Log)); 1788 addGCModeDescription(LOpts, GCEnabled); 1789 } 1790 1791 virtual std::pair<ranges_iterator, ranges_iterator> getRanges() { 1792 const CFRefBug& BugTy = static_cast<CFRefBug&>(getBugType()); 1793 if (!BugTy.isLeak()) 1794 return BugReport::getRanges(); 1795 else 1796 return std::make_pair(ranges_iterator(), ranges_iterator()); 1797 } 1798 }; 1799 1800 class CFRefLeakReport : public CFRefReport { 1801 const MemRegion* AllocBinding; 1802 1803 public: 1804 CFRefLeakReport(CFRefBug &D, const LangOptions &LOpts, bool GCEnabled, 1805 const SummaryLogTy &Log, ExplodedNode *n, SymbolRef sym, 1806 CheckerContext &Ctx); 1807 1808 PathDiagnosticLocation getLocation(const SourceManager &SM) const { 1809 assert(Location.isValid()); 1810 return Location; 1811 } 1812 }; 1813} // end anonymous namespace 1814 1815void CFRefReport::addGCModeDescription(const LangOptions &LOpts, 1816 bool GCEnabled) { 1817 const char *GCModeDescription = 0; 1818 1819 switch (LOpts.getGC()) { 1820 case LangOptions::GCOnly: 1821 assert(GCEnabled); 1822 GCModeDescription = "Code is compiled to only use garbage collection"; 1823 break; 1824 1825 case LangOptions::NonGC: 1826 assert(!GCEnabled); 1827 GCModeDescription = "Code is compiled to use reference counts"; 1828 break; 1829 1830 case LangOptions::HybridGC: 1831 if (GCEnabled) { 1832 GCModeDescription = "Code is compiled to use either garbage collection " 1833 "(GC) or reference counts (non-GC). The bug occurs " 1834 "with GC enabled"; 1835 break; 1836 } else { 1837 GCModeDescription = "Code is compiled to use either garbage collection " 1838 "(GC) or reference counts (non-GC). The bug occurs " 1839 "in non-GC mode"; 1840 break; 1841 } 1842 } 1843 1844 assert(GCModeDescription && "invalid/unknown GC mode"); 1845 addExtraText(GCModeDescription); 1846} 1847 1848// FIXME: This should be a method on SmallVector. 1849static inline bool contains(const SmallVectorImpl<ArgEffect>& V, 1850 ArgEffect X) { 1851 for (SmallVectorImpl<ArgEffect>::const_iterator I=V.begin(), E=V.end(); 1852 I!=E; ++I) 1853 if (*I == X) return true; 1854 1855 return false; 1856} 1857 1858static bool isNumericLiteralExpression(const Expr *E) { 1859 // FIXME: This set of cases was copied from SemaExprObjC. 1860 return isa<IntegerLiteral>(E) || 1861 isa<CharacterLiteral>(E) || 1862 isa<FloatingLiteral>(E) || 1863 isa<ObjCBoolLiteralExpr>(E) || 1864 isa<CXXBoolLiteralExpr>(E); 1865} 1866 1867static bool isPropertyAccess(const Stmt *S, ParentMap &PM) { 1868 unsigned maxDepth = 4; 1869 while (S && maxDepth) { 1870 if (const PseudoObjectExpr *PO = dyn_cast<PseudoObjectExpr>(S)) { 1871 if (!isa<ObjCMessageExpr>(PO->getSyntacticForm())) 1872 return true; 1873 return false; 1874 } 1875 S = PM.getParent(S); 1876 --maxDepth; 1877 } 1878 return false; 1879} 1880 1881PathDiagnosticPiece *CFRefReportVisitor::VisitNode(const ExplodedNode *N, 1882 const ExplodedNode *PrevN, 1883 BugReporterContext &BRC, 1884 BugReport &BR) { 1885 1886 if (!isa<StmtPoint>(N->getLocation())) 1887 return NULL; 1888 1889 // Check if the type state has changed. 1890 ProgramStateRef PrevSt = PrevN->getState(); 1891 ProgramStateRef CurrSt = N->getState(); 1892 const LocationContext *LCtx = N->getLocationContext(); 1893 1894 const RefVal* CurrT = CurrSt->get<RefBindings>(Sym); 1895 if (!CurrT) return NULL; 1896 1897 const RefVal &CurrV = *CurrT; 1898 const RefVal *PrevT = PrevSt->get<RefBindings>(Sym); 1899 1900 // Create a string buffer to constain all the useful things we want 1901 // to tell the user. 1902 std::string sbuf; 1903 llvm::raw_string_ostream os(sbuf); 1904 1905 // This is the allocation site since the previous node had no bindings 1906 // for this symbol. 1907 if (!PrevT) { 1908 const Stmt *S = cast<StmtPoint>(N->getLocation()).getStmt(); 1909 1910 if (isa<ObjCArrayLiteral>(S)) { 1911 os << "NSArray literal is an object with a +0 retain count"; 1912 } 1913 else if (isa<ObjCDictionaryLiteral>(S)) { 1914 os << "NSDictionary literal is an object with a +0 retain count"; 1915 } 1916 else if (const ObjCBoxedExpr *BL = dyn_cast<ObjCBoxedExpr>(S)) { 1917 if (isNumericLiteralExpression(BL->getSubExpr())) 1918 os << "NSNumber literal is an object with a +0 retain count"; 1919 else { 1920 const ObjCInterfaceDecl *BoxClass = 0; 1921 if (const ObjCMethodDecl *Method = BL->getBoxingMethod()) 1922 BoxClass = Method->getClassInterface(); 1923 1924 // We should always be able to find the boxing class interface, 1925 // but consider this future-proofing. 1926 if (BoxClass) 1927 os << *BoxClass << " b"; 1928 else 1929 os << "B"; 1930 1931 os << "oxed expression produces an object with a +0 retain count"; 1932 } 1933 } 1934 else { 1935 if (const CallExpr *CE = dyn_cast<CallExpr>(S)) { 1936 // Get the name of the callee (if it is available). 1937 SVal X = CurrSt->getSValAsScalarOrLoc(CE->getCallee(), LCtx); 1938 if (const FunctionDecl *FD = X.getAsFunctionDecl()) 1939 os << "Call to function '" << *FD << '\''; 1940 else 1941 os << "function call"; 1942 } 1943 else { 1944 assert(isa<ObjCMessageExpr>(S)); 1945 // The message expression may have between written directly or as 1946 // a property access. Lazily determine which case we are looking at. 1947 os << (isPropertyAccess(S, N->getParentMap()) ? "Property" : "Method"); 1948 } 1949 1950 if (CurrV.getObjKind() == RetEffect::CF) { 1951 os << " returns a Core Foundation object with a "; 1952 } 1953 else { 1954 assert (CurrV.getObjKind() == RetEffect::ObjC); 1955 os << " returns an Objective-C object with a "; 1956 } 1957 1958 if (CurrV.isOwned()) { 1959 os << "+1 retain count"; 1960 1961 if (GCEnabled) { 1962 assert(CurrV.getObjKind() == RetEffect::CF); 1963 os << ". " 1964 "Core Foundation objects are not automatically garbage collected."; 1965 } 1966 } 1967 else { 1968 assert (CurrV.isNotOwned()); 1969 os << "+0 retain count"; 1970 } 1971 } 1972 1973 PathDiagnosticLocation Pos(S, BRC.getSourceManager(), 1974 N->getLocationContext()); 1975 return new PathDiagnosticEventPiece(Pos, os.str()); 1976 } 1977 1978 // Gather up the effects that were performed on the object at this 1979 // program point 1980 SmallVector<ArgEffect, 2> AEffects; 1981 1982 const ExplodedNode *OrigNode = BRC.getNodeResolver().getOriginalNode(N); 1983 if (const RetainSummary *Summ = SummaryLog.lookup(OrigNode)) { 1984 // We only have summaries attached to nodes after evaluating CallExpr and 1985 // ObjCMessageExprs. 1986 const Stmt *S = cast<StmtPoint>(N->getLocation()).getStmt(); 1987 1988 if (const CallExpr *CE = dyn_cast<CallExpr>(S)) { 1989 // Iterate through the parameter expressions and see if the symbol 1990 // was ever passed as an argument. 1991 unsigned i = 0; 1992 1993 for (CallExpr::const_arg_iterator AI=CE->arg_begin(), AE=CE->arg_end(); 1994 AI!=AE; ++AI, ++i) { 1995 1996 // Retrieve the value of the argument. Is it the symbol 1997 // we are interested in? 1998 if (CurrSt->getSValAsScalarOrLoc(*AI, LCtx).getAsLocSymbol() != Sym) 1999 continue; 2000 2001 // We have an argument. Get the effect! 2002 AEffects.push_back(Summ->getArg(i)); 2003 } 2004 } 2005 else if (const ObjCMessageExpr *ME = dyn_cast<ObjCMessageExpr>(S)) { 2006 if (const Expr *receiver = ME->getInstanceReceiver()) 2007 if (CurrSt->getSValAsScalarOrLoc(receiver, LCtx) 2008 .getAsLocSymbol() == Sym) { 2009 // The symbol we are tracking is the receiver. 2010 AEffects.push_back(Summ->getReceiverEffect()); 2011 } 2012 } 2013 } 2014 2015 do { 2016 // Get the previous type state. 2017 RefVal PrevV = *PrevT; 2018 2019 // Specially handle -dealloc. 2020 if (!GCEnabled && contains(AEffects, Dealloc)) { 2021 // Determine if the object's reference count was pushed to zero. 2022 assert(!(PrevV == CurrV) && "The typestate *must* have changed."); 2023 // We may not have transitioned to 'release' if we hit an error. 2024 // This case is handled elsewhere. 2025 if (CurrV.getKind() == RefVal::Released) { 2026 assert(CurrV.getCombinedCounts() == 0); 2027 os << "Object released by directly sending the '-dealloc' message"; 2028 break; 2029 } 2030 } 2031 2032 // Specially handle CFMakeCollectable and friends. 2033 if (contains(AEffects, MakeCollectable)) { 2034 // Get the name of the function. 2035 const Stmt *S = cast<StmtPoint>(N->getLocation()).getStmt(); 2036 SVal X = 2037 CurrSt->getSValAsScalarOrLoc(cast<CallExpr>(S)->getCallee(), LCtx); 2038 const FunctionDecl *FD = X.getAsFunctionDecl(); 2039 2040 if (GCEnabled) { 2041 // Determine if the object's reference count was pushed to zero. 2042 assert(!(PrevV == CurrV) && "The typestate *must* have changed."); 2043 2044 os << "In GC mode a call to '" << *FD 2045 << "' decrements an object's retain count and registers the " 2046 "object with the garbage collector. "; 2047 2048 if (CurrV.getKind() == RefVal::Released) { 2049 assert(CurrV.getCount() == 0); 2050 os << "Since it now has a 0 retain count the object can be " 2051 "automatically collected by the garbage collector."; 2052 } 2053 else 2054 os << "An object must have a 0 retain count to be garbage collected. " 2055 "After this call its retain count is +" << CurrV.getCount() 2056 << '.'; 2057 } 2058 else 2059 os << "When GC is not enabled a call to '" << *FD 2060 << "' has no effect on its argument."; 2061 2062 // Nothing more to say. 2063 break; 2064 } 2065 2066 // Determine if the typestate has changed. 2067 if (!(PrevV == CurrV)) 2068 switch (CurrV.getKind()) { 2069 case RefVal::Owned: 2070 case RefVal::NotOwned: 2071 2072 if (PrevV.getCount() == CurrV.getCount()) { 2073 // Did an autorelease message get sent? 2074 if (PrevV.getAutoreleaseCount() == CurrV.getAutoreleaseCount()) 2075 return 0; 2076 2077 assert(PrevV.getAutoreleaseCount() < CurrV.getAutoreleaseCount()); 2078 os << "Object sent -autorelease message"; 2079 break; 2080 } 2081 2082 if (PrevV.getCount() > CurrV.getCount()) 2083 os << "Reference count decremented."; 2084 else 2085 os << "Reference count incremented."; 2086 2087 if (unsigned Count = CurrV.getCount()) 2088 os << " The object now has a +" << Count << " retain count."; 2089 2090 if (PrevV.getKind() == RefVal::Released) { 2091 assert(GCEnabled && CurrV.getCount() > 0); 2092 os << " The object is not eligible for garbage collection until " 2093 "the retain count reaches 0 again."; 2094 } 2095 2096 break; 2097 2098 case RefVal::Released: 2099 os << "Object released."; 2100 break; 2101 2102 case RefVal::ReturnedOwned: 2103 // Autoreleases can be applied after marking a node ReturnedOwned. 2104 if (CurrV.getAutoreleaseCount()) 2105 return NULL; 2106 2107 os << "Object returned to caller as an owning reference (single " 2108 "retain count transferred to caller)"; 2109 break; 2110 2111 case RefVal::ReturnedNotOwned: 2112 os << "Object returned to caller with a +0 retain count"; 2113 break; 2114 2115 default: 2116 return NULL; 2117 } 2118 2119 // Emit any remaining diagnostics for the argument effects (if any). 2120 for (SmallVectorImpl<ArgEffect>::iterator I=AEffects.begin(), 2121 E=AEffects.end(); I != E; ++I) { 2122 2123 // A bunch of things have alternate behavior under GC. 2124 if (GCEnabled) 2125 switch (*I) { 2126 default: break; 2127 case Autorelease: 2128 os << "In GC mode an 'autorelease' has no effect."; 2129 continue; 2130 case IncRefMsg: 2131 os << "In GC mode the 'retain' message has no effect."; 2132 continue; 2133 case DecRefMsg: 2134 os << "In GC mode the 'release' message has no effect."; 2135 continue; 2136 } 2137 } 2138 } while (0); 2139 2140 if (os.str().empty()) 2141 return 0; // We have nothing to say! 2142 2143 const Stmt *S = cast<StmtPoint>(N->getLocation()).getStmt(); 2144 PathDiagnosticLocation Pos(S, BRC.getSourceManager(), 2145 N->getLocationContext()); 2146 PathDiagnosticPiece *P = new PathDiagnosticEventPiece(Pos, os.str()); 2147 2148 // Add the range by scanning the children of the statement for any bindings 2149 // to Sym. 2150 for (Stmt::const_child_iterator I = S->child_begin(), E = S->child_end(); 2151 I!=E; ++I) 2152 if (const Expr *Exp = dyn_cast_or_null<Expr>(*I)) 2153 if (CurrSt->getSValAsScalarOrLoc(Exp, LCtx).getAsLocSymbol() == Sym) { 2154 P->addRange(Exp->getSourceRange()); 2155 break; 2156 } 2157 2158 return P; 2159} 2160 2161// Find the first node in the current function context that referred to the 2162// tracked symbol and the memory location that value was stored to. Note, the 2163// value is only reported if the allocation occurred in the same function as 2164// the leak. 2165static std::pair<const ExplodedNode*,const MemRegion*> 2166GetAllocationSite(ProgramStateManager& StateMgr, const ExplodedNode *N, 2167 SymbolRef Sym) { 2168 const ExplodedNode *Last = N; 2169 const MemRegion* FirstBinding = 0; 2170 const LocationContext *LeakContext = N->getLocationContext(); 2171 2172 while (N) { 2173 ProgramStateRef St = N->getState(); 2174 RefBindings B = St->get<RefBindings>(); 2175 2176 if (!B.lookup(Sym)) 2177 break; 2178 2179 StoreManager::FindUniqueBinding FB(Sym); 2180 StateMgr.iterBindings(St, FB); 2181 if (FB) FirstBinding = FB.getRegion(); 2182 2183 // Allocation node, is the last node in the current context in which the 2184 // symbol was tracked. 2185 if (N->getLocationContext() == LeakContext) 2186 Last = N; 2187 2188 N = N->pred_empty() ? NULL : *(N->pred_begin()); 2189 } 2190 2191 // If allocation happened in a function different from the leak node context, 2192 // do not report the binding. 2193 if (N->getLocationContext() != LeakContext) { 2194 FirstBinding = 0; 2195 } 2196 2197 return std::make_pair(Last, FirstBinding); 2198} 2199 2200PathDiagnosticPiece* 2201CFRefReportVisitor::getEndPath(BugReporterContext &BRC, 2202 const ExplodedNode *EndN, 2203 BugReport &BR) { 2204 BR.markInteresting(Sym); 2205 return BugReporterVisitor::getDefaultEndPath(BRC, EndN, BR); 2206} 2207 2208PathDiagnosticPiece* 2209CFRefLeakReportVisitor::getEndPath(BugReporterContext &BRC, 2210 const ExplodedNode *EndN, 2211 BugReport &BR) { 2212 2213 // Tell the BugReporterContext to report cases when the tracked symbol is 2214 // assigned to different variables, etc. 2215 BR.markInteresting(Sym); 2216 2217 // We are reporting a leak. Walk up the graph to get to the first node where 2218 // the symbol appeared, and also get the first VarDecl that tracked object 2219 // is stored to. 2220 const ExplodedNode *AllocNode = 0; 2221 const MemRegion* FirstBinding = 0; 2222 2223 llvm::tie(AllocNode, FirstBinding) = 2224 GetAllocationSite(BRC.getStateManager(), EndN, Sym); 2225 2226 SourceManager& SM = BRC.getSourceManager(); 2227 2228 // Compute an actual location for the leak. Sometimes a leak doesn't 2229 // occur at an actual statement (e.g., transition between blocks; end 2230 // of function) so we need to walk the graph and compute a real location. 2231 const ExplodedNode *LeakN = EndN; 2232 PathDiagnosticLocation L = PathDiagnosticLocation::createEndOfPath(LeakN, SM); 2233 2234 std::string sbuf; 2235 llvm::raw_string_ostream os(sbuf); 2236 2237 os << "Object leaked: "; 2238 2239 if (FirstBinding) { 2240 os << "object allocated and stored into '" 2241 << FirstBinding->getString() << '\''; 2242 } 2243 else 2244 os << "allocated object"; 2245 2246 // Get the retain count. 2247 const RefVal* RV = EndN->getState()->get<RefBindings>(Sym); 2248 2249 if (RV->getKind() == RefVal::ErrorLeakReturned) { 2250 // FIXME: Per comments in rdar://6320065, "create" only applies to CF 2251 // objects. Only "copy", "alloc", "retain" and "new" transfer ownership 2252 // to the caller for NS objects. 2253 const Decl *D = &EndN->getCodeDecl(); 2254 if (const ObjCMethodDecl *MD = dyn_cast<ObjCMethodDecl>(D)) { 2255 os << " is returned from a method whose name ('" 2256 << MD->getSelector().getAsString() 2257 << "') does not start with 'copy', 'mutableCopy', 'alloc' or 'new'." 2258 " This violates the naming convention rules" 2259 " given in the Memory Management Guide for Cocoa"; 2260 } 2261 else { 2262 const FunctionDecl *FD = cast<FunctionDecl>(D); 2263 os << " is returned from a function whose name ('" 2264 << *FD 2265 << "') does not contain 'Copy' or 'Create'. This violates the naming" 2266 " convention rules given in the Memory Management Guide for Core" 2267 " Foundation"; 2268 } 2269 } 2270 else if (RV->getKind() == RefVal::ErrorGCLeakReturned) { 2271 ObjCMethodDecl &MD = cast<ObjCMethodDecl>(EndN->getCodeDecl()); 2272 os << " and returned from method '" << MD.getSelector().getAsString() 2273 << "' is potentially leaked when using garbage collection. Callers " 2274 "of this method do not expect a returned object with a +1 retain " 2275 "count since they expect the object to be managed by the garbage " 2276 "collector"; 2277 } 2278 else 2279 os << " is not referenced later in this execution path and has a retain " 2280 "count of +" << RV->getCount(); 2281 2282 return new PathDiagnosticEventPiece(L, os.str()); 2283} 2284 2285CFRefLeakReport::CFRefLeakReport(CFRefBug &D, const LangOptions &LOpts, 2286 bool GCEnabled, const SummaryLogTy &Log, 2287 ExplodedNode *n, SymbolRef sym, 2288 CheckerContext &Ctx) 2289: CFRefReport(D, LOpts, GCEnabled, Log, n, sym, false) { 2290 2291 // Most bug reports are cached at the location where they occurred. 2292 // With leaks, we want to unique them by the location where they were 2293 // allocated, and only report a single path. To do this, we need to find 2294 // the allocation site of a piece of tracked memory, which we do via a 2295 // call to GetAllocationSite. This will walk the ExplodedGraph backwards. 2296 // Note that this is *not* the trimmed graph; we are guaranteed, however, 2297 // that all ancestor nodes that represent the allocation site have the 2298 // same SourceLocation. 2299 const ExplodedNode *AllocNode = 0; 2300 2301 const SourceManager& SMgr = Ctx.getSourceManager(); 2302 2303 llvm::tie(AllocNode, AllocBinding) = // Set AllocBinding. 2304 GetAllocationSite(Ctx.getStateManager(), getErrorNode(), sym); 2305 2306 // Get the SourceLocation for the allocation site. 2307 ProgramPoint P = AllocNode->getLocation(); 2308 const Stmt *AllocStmt = cast<PostStmt>(P).getStmt(); 2309 Location = PathDiagnosticLocation::createBegin(AllocStmt, SMgr, 2310 n->getLocationContext()); 2311 // Fill in the description of the bug. 2312 Description.clear(); 2313 llvm::raw_string_ostream os(Description); 2314 os << "Potential leak "; 2315 if (GCEnabled) 2316 os << "(when using garbage collection) "; 2317 os << "of an object"; 2318 2319 // FIXME: AllocBinding doesn't get populated for RegionStore yet. 2320 if (AllocBinding) 2321 os << " stored into '" << AllocBinding->getString() << '\''; 2322 2323 addVisitor(new CFRefLeakReportVisitor(sym, GCEnabled, Log)); 2324} 2325 2326//===----------------------------------------------------------------------===// 2327// Main checker logic. 2328//===----------------------------------------------------------------------===// 2329 2330namespace { 2331class RetainCountChecker 2332 : public Checker< check::Bind, 2333 check::DeadSymbols, 2334 check::EndAnalysis, 2335 check::EndPath, 2336 check::PostStmt<BlockExpr>, 2337 check::PostStmt<CastExpr>, 2338 check::PostStmt<CallExpr>, 2339 check::PostStmt<CXXConstructExpr>, 2340 check::PostStmt<ObjCArrayLiteral>, 2341 check::PostStmt<ObjCDictionaryLiteral>, 2342 check::PostStmt<ObjCBoxedExpr>, 2343 check::PostObjCMessage, 2344 check::PreStmt<ReturnStmt>, 2345 check::RegionChanges, 2346 eval::Assume, 2347 eval::Call > { 2348 mutable OwningPtr<CFRefBug> useAfterRelease, releaseNotOwned; 2349 mutable OwningPtr<CFRefBug> deallocGC, deallocNotOwned; 2350 mutable OwningPtr<CFRefBug> overAutorelease, returnNotOwnedForOwned; 2351 mutable OwningPtr<CFRefBug> leakWithinFunction, leakAtReturn; 2352 mutable OwningPtr<CFRefBug> leakWithinFunctionGC, leakAtReturnGC; 2353 2354 typedef llvm::DenseMap<SymbolRef, const SimpleProgramPointTag *> SymbolTagMap; 2355 2356 // This map is only used to ensure proper deletion of any allocated tags. 2357 mutable SymbolTagMap DeadSymbolTags; 2358 2359 mutable OwningPtr<RetainSummaryManager> Summaries; 2360 mutable OwningPtr<RetainSummaryManager> SummariesGC; 2361 2362 mutable ARCounts::Factory ARCountFactory; 2363 2364 mutable SummaryLogTy SummaryLog; 2365 mutable bool ShouldResetSummaryLog; 2366 2367public: 2368 RetainCountChecker() : ShouldResetSummaryLog(false) {} 2369 2370 virtual ~RetainCountChecker() { 2371 DeleteContainerSeconds(DeadSymbolTags); 2372 } 2373 2374 void checkEndAnalysis(ExplodedGraph &G, BugReporter &BR, 2375 ExprEngine &Eng) const { 2376 // FIXME: This is a hack to make sure the summary log gets cleared between 2377 // analyses of different code bodies. 2378 // 2379 // Why is this necessary? Because a checker's lifetime is tied to a 2380 // translation unit, but an ExplodedGraph's lifetime is just a code body. 2381 // Once in a blue moon, a new ExplodedNode will have the same address as an 2382 // old one with an associated summary, and the bug report visitor gets very 2383 // confused. (To make things worse, the summary lifetime is currently also 2384 // tied to a code body, so we get a crash instead of incorrect results.) 2385 // 2386 // Why is this a bad solution? Because if the lifetime of the ExplodedGraph 2387 // changes, things will start going wrong again. Really the lifetime of this 2388 // log needs to be tied to either the specific nodes in it or the entire 2389 // ExplodedGraph, not to a specific part of the code being analyzed. 2390 // 2391 // (Also, having stateful local data means that the same checker can't be 2392 // used from multiple threads, but a lot of checkers have incorrect 2393 // assumptions about that anyway. So that wasn't a priority at the time of 2394 // this fix.) 2395 // 2396 // This happens at the end of analysis, but bug reports are emitted /after/ 2397 // this point. So we can't just clear the summary log now. Instead, we mark 2398 // that the next time we access the summary log, it should be cleared. 2399 2400 // If we never reset the summary log during /this/ code body analysis, 2401 // there were no new summaries. There might still have been summaries from 2402 // the /last/ analysis, so clear them out to make sure the bug report 2403 // visitors don't get confused. 2404 if (ShouldResetSummaryLog) 2405 SummaryLog.clear(); 2406 2407 ShouldResetSummaryLog = !SummaryLog.empty(); 2408 } 2409 2410 CFRefBug *getLeakWithinFunctionBug(const LangOptions &LOpts, 2411 bool GCEnabled) const { 2412 if (GCEnabled) { 2413 if (!leakWithinFunctionGC) 2414 leakWithinFunctionGC.reset(new Leak("Leak of object when using " 2415 "garbage collection")); 2416 return leakWithinFunctionGC.get(); 2417 } else { 2418 if (!leakWithinFunction) { 2419 if (LOpts.getGC() == LangOptions::HybridGC) { 2420 leakWithinFunction.reset(new Leak("Leak of object when not using " 2421 "garbage collection (GC) in " 2422 "dual GC/non-GC code")); 2423 } else { 2424 leakWithinFunction.reset(new Leak("Leak")); 2425 } 2426 } 2427 return leakWithinFunction.get(); 2428 } 2429 } 2430 2431 CFRefBug *getLeakAtReturnBug(const LangOptions &LOpts, bool GCEnabled) const { 2432 if (GCEnabled) { 2433 if (!leakAtReturnGC) 2434 leakAtReturnGC.reset(new Leak("Leak of returned object when using " 2435 "garbage collection")); 2436 return leakAtReturnGC.get(); 2437 } else { 2438 if (!leakAtReturn) { 2439 if (LOpts.getGC() == LangOptions::HybridGC) { 2440 leakAtReturn.reset(new Leak("Leak of returned object when not using " 2441 "garbage collection (GC) in dual " 2442 "GC/non-GC code")); 2443 } else { 2444 leakAtReturn.reset(new Leak("Leak of returned object")); 2445 } 2446 } 2447 return leakAtReturn.get(); 2448 } 2449 } 2450 2451 RetainSummaryManager &getSummaryManager(ASTContext &Ctx, 2452 bool GCEnabled) const { 2453 // FIXME: We don't support ARC being turned on and off during one analysis. 2454 // (nor, for that matter, do we support changing ASTContexts) 2455 bool ARCEnabled = (bool)Ctx.getLangOpts().ObjCAutoRefCount; 2456 if (GCEnabled) { 2457 if (!SummariesGC) 2458 SummariesGC.reset(new RetainSummaryManager(Ctx, true, ARCEnabled)); 2459 else 2460 assert(SummariesGC->isARCEnabled() == ARCEnabled); 2461 return *SummariesGC; 2462 } else { 2463 if (!Summaries) 2464 Summaries.reset(new RetainSummaryManager(Ctx, false, ARCEnabled)); 2465 else 2466 assert(Summaries->isARCEnabled() == ARCEnabled); 2467 return *Summaries; 2468 } 2469 } 2470 2471 RetainSummaryManager &getSummaryManager(CheckerContext &C) const { 2472 return getSummaryManager(C.getASTContext(), C.isObjCGCEnabled()); 2473 } 2474 2475 void printState(raw_ostream &Out, ProgramStateRef State, 2476 const char *NL, const char *Sep) const; 2477 2478 void checkBind(SVal loc, SVal val, const Stmt *S, CheckerContext &C) const; 2479 void checkPostStmt(const BlockExpr *BE, CheckerContext &C) const; 2480 void checkPostStmt(const CastExpr *CE, CheckerContext &C) const; 2481 2482 void checkPostStmt(const CallExpr *CE, CheckerContext &C) const; 2483 void checkPostStmt(const CXXConstructExpr *CE, CheckerContext &C) const; 2484 void checkPostStmt(const ObjCArrayLiteral *AL, CheckerContext &C) const; 2485 void checkPostStmt(const ObjCDictionaryLiteral *DL, CheckerContext &C) const; 2486 void checkPostStmt(const ObjCBoxedExpr *BE, CheckerContext &C) const; 2487 2488 void checkPostObjCMessage(const ObjCMessage &Msg, CheckerContext &C) const; 2489 2490 void checkSummary(const RetainSummary &Summ, const CallOrObjCMessage &Call, 2491 CheckerContext &C) const; 2492 2493 bool evalCall(const CallExpr *CE, CheckerContext &C) const; 2494 2495 ProgramStateRef evalAssume(ProgramStateRef state, SVal Cond, 2496 bool Assumption) const; 2497 2498 ProgramStateRef 2499 checkRegionChanges(ProgramStateRef state, 2500 const StoreManager::InvalidatedSymbols *invalidated, 2501 ArrayRef<const MemRegion *> ExplicitRegions, 2502 ArrayRef<const MemRegion *> Regions, 2503 const CallEvent *Call) const; 2504 2505 bool wantsRegionChangeUpdate(ProgramStateRef state) const { 2506 return true; 2507 } 2508 2509 void checkPreStmt(const ReturnStmt *S, CheckerContext &C) const; 2510 void checkReturnWithRetEffect(const ReturnStmt *S, CheckerContext &C, 2511 ExplodedNode *Pred, RetEffect RE, RefVal X, 2512 SymbolRef Sym, ProgramStateRef state) const; 2513 2514 void checkDeadSymbols(SymbolReaper &SymReaper, CheckerContext &C) const; 2515 void checkEndPath(CheckerContext &C) const; 2516 2517 ProgramStateRef updateSymbol(ProgramStateRef state, SymbolRef sym, 2518 RefVal V, ArgEffect E, RefVal::Kind &hasErr, 2519 CheckerContext &C) const; 2520 2521 void processNonLeakError(ProgramStateRef St, SourceRange ErrorRange, 2522 RefVal::Kind ErrorKind, SymbolRef Sym, 2523 CheckerContext &C) const; 2524 2525 void processObjCLiterals(CheckerContext &C, const Expr *Ex) const; 2526 2527 const ProgramPointTag *getDeadSymbolTag(SymbolRef sym) const; 2528 2529 ProgramStateRef handleSymbolDeath(ProgramStateRef state, 2530 SymbolRef sid, RefVal V, 2531 SmallVectorImpl<SymbolRef> &Leaked) const; 2532 2533 std::pair<ExplodedNode *, ProgramStateRef > 2534 handleAutoreleaseCounts(ProgramStateRef state, 2535 GenericNodeBuilderRefCount Bd, ExplodedNode *Pred, 2536 CheckerContext &Ctx, SymbolRef Sym, RefVal V) const; 2537 2538 ExplodedNode *processLeaks(ProgramStateRef state, 2539 SmallVectorImpl<SymbolRef> &Leaked, 2540 GenericNodeBuilderRefCount &Builder, 2541 CheckerContext &Ctx, 2542 ExplodedNode *Pred = 0) const; 2543}; 2544} // end anonymous namespace 2545 2546namespace { 2547class StopTrackingCallback : public SymbolVisitor { 2548 ProgramStateRef state; 2549public: 2550 StopTrackingCallback(ProgramStateRef st) : state(st) {} 2551 ProgramStateRef getState() const { return state; } 2552 2553 bool VisitSymbol(SymbolRef sym) { 2554 state = state->remove<RefBindings>(sym); 2555 return true; 2556 } 2557}; 2558} // end anonymous namespace 2559 2560//===----------------------------------------------------------------------===// 2561// Handle statements that may have an effect on refcounts. 2562//===----------------------------------------------------------------------===// 2563 2564void RetainCountChecker::checkPostStmt(const BlockExpr *BE, 2565 CheckerContext &C) const { 2566 2567 // Scan the BlockDecRefExprs for any object the retain count checker 2568 // may be tracking. 2569 if (!BE->getBlockDecl()->hasCaptures()) 2570 return; 2571 2572 ProgramStateRef state = C.getState(); 2573 const BlockDataRegion *R = 2574 cast<BlockDataRegion>(state->getSVal(BE, 2575 C.getLocationContext()).getAsRegion()); 2576 2577 BlockDataRegion::referenced_vars_iterator I = R->referenced_vars_begin(), 2578 E = R->referenced_vars_end(); 2579 2580 if (I == E) 2581 return; 2582 2583 // FIXME: For now we invalidate the tracking of all symbols passed to blocks 2584 // via captured variables, even though captured variables result in a copy 2585 // and in implicit increment/decrement of a retain count. 2586 SmallVector<const MemRegion*, 10> Regions; 2587 const LocationContext *LC = C.getLocationContext(); 2588 MemRegionManager &MemMgr = C.getSValBuilder().getRegionManager(); 2589 2590 for ( ; I != E; ++I) { 2591 const VarRegion *VR = *I; 2592 if (VR->getSuperRegion() == R) { 2593 VR = MemMgr.getVarRegion(VR->getDecl(), LC); 2594 } 2595 Regions.push_back(VR); 2596 } 2597 2598 state = 2599 state->scanReachableSymbols<StopTrackingCallback>(Regions.data(), 2600 Regions.data() + Regions.size()).getState(); 2601 C.addTransition(state); 2602} 2603 2604void RetainCountChecker::checkPostStmt(const CastExpr *CE, 2605 CheckerContext &C) const { 2606 const ObjCBridgedCastExpr *BE = dyn_cast<ObjCBridgedCastExpr>(CE); 2607 if (!BE) 2608 return; 2609 2610 ArgEffect AE = IncRef; 2611 2612 switch (BE->getBridgeKind()) { 2613 case clang::OBC_Bridge: 2614 // Do nothing. 2615 return; 2616 case clang::OBC_BridgeRetained: 2617 AE = IncRef; 2618 break; 2619 case clang::OBC_BridgeTransfer: 2620 AE = DecRefBridgedTransfered; 2621 break; 2622 } 2623 2624 ProgramStateRef state = C.getState(); 2625 SymbolRef Sym = state->getSVal(CE, C.getLocationContext()).getAsLocSymbol(); 2626 if (!Sym) 2627 return; 2628 const RefVal* T = state->get<RefBindings>(Sym); 2629 if (!T) 2630 return; 2631 2632 RefVal::Kind hasErr = (RefVal::Kind) 0; 2633 state = updateSymbol(state, Sym, *T, AE, hasErr, C); 2634 2635 if (hasErr) { 2636 // FIXME: If we get an error during a bridge cast, should we report it? 2637 // Should we assert that there is no error? 2638 return; 2639 } 2640 2641 C.addTransition(state); 2642} 2643 2644void RetainCountChecker::checkPostStmt(const CallExpr *CE, 2645 CheckerContext &C) const { 2646 if (C.wasInlined) 2647 return; 2648 2649 // Get the callee. 2650 ProgramStateRef state = C.getState(); 2651 const Expr *Callee = CE->getCallee(); 2652 SVal L = state->getSVal(Callee, C.getLocationContext()); 2653 2654 RetainSummaryManager &Summaries = getSummaryManager(C); 2655 const RetainSummary *Summ = 0; 2656 2657 // FIXME: Better support for blocks. For now we stop tracking anything 2658 // that is passed to blocks. 2659 // FIXME: Need to handle variables that are "captured" by the block. 2660 if (dyn_cast_or_null<BlockDataRegion>(L.getAsRegion())) { 2661 Summ = Summaries.getPersistentStopSummary(); 2662 } else if (const FunctionDecl *FD = L.getAsFunctionDecl()) { 2663 CallOrObjCMessage CME(CE, state, C.getLocationContext()); 2664 Summ = Summaries.getSummary(FD, &CME); 2665 } else if (const CXXMemberCallExpr *me = dyn_cast<CXXMemberCallExpr>(CE)) { 2666 if (const CXXMethodDecl *MD = me->getMethodDecl()) { 2667 CallOrObjCMessage CME(CE, state, C.getLocationContext()); 2668 Summ = Summaries.getSummary(MD, &CME); 2669 } 2670 } 2671 2672 if (!Summ) 2673 Summ = Summaries.getDefaultSummary(); 2674 2675 checkSummary(*Summ, CallOrObjCMessage(CE, state, C.getLocationContext()), C); 2676} 2677 2678void RetainCountChecker::checkPostStmt(const CXXConstructExpr *CE, 2679 CheckerContext &C) const { 2680 const CXXConstructorDecl *Ctor = CE->getConstructor(); 2681 if (!Ctor) 2682 return; 2683 2684 RetainSummaryManager &Summaries = getSummaryManager(C); 2685 ProgramStateRef state = C.getState(); 2686 CallOrObjCMessage CME(CE, state, C.getLocationContext()); 2687 const RetainSummary *Summ = Summaries.getSummary(Ctor, &CME); 2688 2689 // If we didn't get a summary, this constructor doesn't affect retain counts. 2690 if (!Summ) 2691 return; 2692 2693 checkSummary(*Summ, CallOrObjCMessage(CE, state, C.getLocationContext()), C); 2694} 2695 2696void RetainCountChecker::processObjCLiterals(CheckerContext &C, 2697 const Expr *Ex) const { 2698 ProgramStateRef state = C.getState(); 2699 const ExplodedNode *pred = C.getPredecessor(); 2700 for (Stmt::const_child_iterator it = Ex->child_begin(), et = Ex->child_end() ; 2701 it != et ; ++it) { 2702 const Stmt *child = *it; 2703 SVal V = state->getSVal(child, pred->getLocationContext()); 2704 if (SymbolRef sym = V.getAsSymbol()) 2705 if (const RefVal* T = state->get<RefBindings>(sym)) { 2706 RefVal::Kind hasErr = (RefVal::Kind) 0; 2707 state = updateSymbol(state, sym, *T, MayEscape, hasErr, C); 2708 if (hasErr) { 2709 processNonLeakError(state, child->getSourceRange(), hasErr, sym, C); 2710 return; 2711 } 2712 } 2713 } 2714 2715 // Return the object as autoreleased. 2716 // RetEffect RE = RetEffect::MakeNotOwned(RetEffect::ObjC); 2717 if (SymbolRef sym = 2718 state->getSVal(Ex, pred->getLocationContext()).getAsSymbol()) { 2719 QualType ResultTy = Ex->getType(); 2720 state = state->set<RefBindings>(sym, RefVal::makeNotOwned(RetEffect::ObjC, 2721 ResultTy)); 2722 } 2723 2724 C.addTransition(state); 2725} 2726 2727void RetainCountChecker::checkPostStmt(const ObjCArrayLiteral *AL, 2728 CheckerContext &C) const { 2729 // Apply the 'MayEscape' to all values. 2730 processObjCLiterals(C, AL); 2731} 2732 2733void RetainCountChecker::checkPostStmt(const ObjCDictionaryLiteral *DL, 2734 CheckerContext &C) const { 2735 // Apply the 'MayEscape' to all keys and values. 2736 processObjCLiterals(C, DL); 2737} 2738 2739void RetainCountChecker::checkPostStmt(const ObjCBoxedExpr *Ex, 2740 CheckerContext &C) const { 2741 const ExplodedNode *Pred = C.getPredecessor(); 2742 const LocationContext *LCtx = Pred->getLocationContext(); 2743 ProgramStateRef State = Pred->getState(); 2744 2745 if (SymbolRef Sym = State->getSVal(Ex, LCtx).getAsSymbol()) { 2746 QualType ResultTy = Ex->getType(); 2747 State = State->set<RefBindings>(Sym, RefVal::makeNotOwned(RetEffect::ObjC, 2748 ResultTy)); 2749 } 2750 2751 C.addTransition(State); 2752} 2753 2754void RetainCountChecker::checkPostObjCMessage(const ObjCMessage &Msg, 2755 CheckerContext &C) const { 2756 ProgramStateRef state = C.getState(); 2757 2758 RetainSummaryManager &Summaries = getSummaryManager(C); 2759 2760 const RetainSummary *Summ; 2761 if (Msg.isInstanceMessage()) { 2762 const LocationContext *LC = C.getLocationContext(); 2763 Summ = Summaries.getInstanceMethodSummary(Msg, state, LC); 2764 } else { 2765 Summ = Summaries.getClassMethodSummary(Msg); 2766 } 2767 2768 // If we didn't get a summary, this message doesn't affect retain counts. 2769 if (!Summ) 2770 return; 2771 2772 checkSummary(*Summ, CallOrObjCMessage(Msg, state, C.getLocationContext()), C); 2773} 2774 2775/// GetReturnType - Used to get the return type of a message expression or 2776/// function call with the intention of affixing that type to a tracked symbol. 2777/// While the the return type can be queried directly from RetEx, when 2778/// invoking class methods we augment to the return type to be that of 2779/// a pointer to the class (as opposed it just being id). 2780// FIXME: We may be able to do this with related result types instead. 2781// This function is probably overestimating. 2782static QualType GetReturnType(const Expr *RetE, ASTContext &Ctx) { 2783 QualType RetTy = RetE->getType(); 2784 // If RetE is not a message expression just return its type. 2785 // If RetE is a message expression, return its types if it is something 2786 /// more specific than id. 2787 if (const ObjCMessageExpr *ME = dyn_cast<ObjCMessageExpr>(RetE)) 2788 if (const ObjCObjectPointerType *PT = RetTy->getAs<ObjCObjectPointerType>()) 2789 if (PT->isObjCQualifiedIdType() || PT->isObjCIdType() || 2790 PT->isObjCClassType()) { 2791 // At this point we know the return type of the message expression is 2792 // id, id<...>, or Class. If we have an ObjCInterfaceDecl, we know this 2793 // is a call to a class method whose type we can resolve. In such 2794 // cases, promote the return type to XXX* (where XXX is the class). 2795 const ObjCInterfaceDecl *D = ME->getReceiverInterface(); 2796 return !D ? RetTy : 2797 Ctx.getObjCObjectPointerType(Ctx.getObjCInterfaceType(D)); 2798 } 2799 2800 return RetTy; 2801} 2802 2803void RetainCountChecker::checkSummary(const RetainSummary &Summ, 2804 const CallOrObjCMessage &CallOrMsg, 2805 CheckerContext &C) const { 2806 ProgramStateRef state = C.getState(); 2807 2808 // Evaluate the effect of the arguments. 2809 RefVal::Kind hasErr = (RefVal::Kind) 0; 2810 SourceRange ErrorRange; 2811 SymbolRef ErrorSym = 0; 2812 2813 for (unsigned idx = 0, e = CallOrMsg.getNumArgs(); idx != e; ++idx) { 2814 SVal V = CallOrMsg.getArgSVal(idx); 2815 2816 if (SymbolRef Sym = V.getAsLocSymbol()) { 2817 if (RefBindings::data_type *T = state->get<RefBindings>(Sym)) { 2818 state = updateSymbol(state, Sym, *T, Summ.getArg(idx), hasErr, C); 2819 if (hasErr) { 2820 ErrorRange = CallOrMsg.getArgSourceRange(idx); 2821 ErrorSym = Sym; 2822 break; 2823 } 2824 } 2825 } 2826 } 2827 2828 // Evaluate the effect on the message receiver. 2829 bool ReceiverIsTracked = false; 2830 if (!hasErr && CallOrMsg.isObjCMessage()) { 2831 const LocationContext *LC = C.getLocationContext(); 2832 SVal Receiver = CallOrMsg.getInstanceMessageReceiver(LC); 2833 if (SymbolRef Sym = Receiver.getAsLocSymbol()) { 2834 if (const RefVal *T = state->get<RefBindings>(Sym)) { 2835 ReceiverIsTracked = true; 2836 state = updateSymbol(state, Sym, *T, Summ.getReceiverEffect(), 2837 hasErr, C); 2838 if (hasErr) { 2839 ErrorRange = CallOrMsg.getReceiverSourceRange(); 2840 ErrorSym = Sym; 2841 } 2842 } 2843 } 2844 } 2845 2846 // Process any errors. 2847 if (hasErr) { 2848 processNonLeakError(state, ErrorRange, hasErr, ErrorSym, C); 2849 return; 2850 } 2851 2852 // Consult the summary for the return value. 2853 RetEffect RE = Summ.getRetEffect(); 2854 2855 if (RE.getKind() == RetEffect::OwnedWhenTrackedReceiver) { 2856 if (ReceiverIsTracked) 2857 RE = getSummaryManager(C).getObjAllocRetEffect(); 2858 else 2859 RE = RetEffect::MakeNoRet(); 2860 } 2861 2862 switch (RE.getKind()) { 2863 default: 2864 llvm_unreachable("Unhandled RetEffect."); 2865 2866 case RetEffect::NoRet: 2867 // No work necessary. 2868 break; 2869 2870 case RetEffect::OwnedAllocatedSymbol: 2871 case RetEffect::OwnedSymbol: { 2872 SymbolRef Sym = state->getSVal(CallOrMsg.getOriginExpr(), 2873 C.getLocationContext()).getAsSymbol(); 2874 if (!Sym) 2875 break; 2876 2877 // Use the result type from callOrMsg as it automatically adjusts 2878 // for methods/functions that return references. 2879 QualType ResultTy = CallOrMsg.getResultType(C.getASTContext()); 2880 state = state->set<RefBindings>(Sym, RefVal::makeOwned(RE.getObjKind(), 2881 ResultTy)); 2882 2883 // FIXME: Add a flag to the checker where allocations are assumed to 2884 // *not* fail. (The code below is out-of-date, though.) 2885#if 0 2886 if (RE.getKind() == RetEffect::OwnedAllocatedSymbol) { 2887 bool isFeasible; 2888 state = state.assume(loc::SymbolVal(Sym), true, isFeasible); 2889 assert(isFeasible && "Cannot assume fresh symbol is non-null."); 2890 } 2891#endif 2892 2893 break; 2894 } 2895 2896 case RetEffect::GCNotOwnedSymbol: 2897 case RetEffect::ARCNotOwnedSymbol: 2898 case RetEffect::NotOwnedSymbol: { 2899 const Expr *Ex = CallOrMsg.getOriginExpr(); 2900 SymbolRef Sym = state->getSVal(Ex, C.getLocationContext()).getAsSymbol(); 2901 if (!Sym) 2902 break; 2903 2904 // Use GetReturnType in order to give [NSFoo alloc] the type NSFoo *. 2905 QualType ResultTy = GetReturnType(Ex, C.getASTContext()); 2906 state = state->set<RefBindings>(Sym, RefVal::makeNotOwned(RE.getObjKind(), 2907 ResultTy)); 2908 break; 2909 } 2910 } 2911 2912 // This check is actually necessary; otherwise the statement builder thinks 2913 // we've hit a previously-found path. 2914 // Normally addTransition takes care of this, but we want the node pointer. 2915 ExplodedNode *NewNode; 2916 if (state == C.getState()) { 2917 NewNode = C.getPredecessor(); 2918 } else { 2919 NewNode = C.addTransition(state); 2920 } 2921 2922 // Annotate the node with summary we used. 2923 if (NewNode) { 2924 // FIXME: This is ugly. See checkEndAnalysis for why it's necessary. 2925 if (ShouldResetSummaryLog) { 2926 SummaryLog.clear(); 2927 ShouldResetSummaryLog = false; 2928 } 2929 SummaryLog[NewNode] = &Summ; 2930 } 2931} 2932 2933 2934ProgramStateRef 2935RetainCountChecker::updateSymbol(ProgramStateRef state, SymbolRef sym, 2936 RefVal V, ArgEffect E, RefVal::Kind &hasErr, 2937 CheckerContext &C) const { 2938 // In GC mode [... release] and [... retain] do nothing. 2939 // In ARC mode they shouldn't exist at all, but we just ignore them. 2940 bool IgnoreRetainMsg = C.isObjCGCEnabled(); 2941 if (!IgnoreRetainMsg) 2942 IgnoreRetainMsg = (bool)C.getASTContext().getLangOpts().ObjCAutoRefCount; 2943 2944 switch (E) { 2945 default: break; 2946 case IncRefMsg: E = IgnoreRetainMsg ? DoNothing : IncRef; break; 2947 case DecRefMsg: E = IgnoreRetainMsg ? DoNothing : DecRef; break; 2948 case MakeCollectable: E = C.isObjCGCEnabled() ? DecRef : DoNothing; break; 2949 case NewAutoreleasePool: E = C.isObjCGCEnabled() ? DoNothing : 2950 NewAutoreleasePool; break; 2951 } 2952 2953 // Handle all use-after-releases. 2954 if (!C.isObjCGCEnabled() && V.getKind() == RefVal::Released) { 2955 V = V ^ RefVal::ErrorUseAfterRelease; 2956 hasErr = V.getKind(); 2957 return state->set<RefBindings>(sym, V); 2958 } 2959 2960 switch (E) { 2961 case DecRefMsg: 2962 case IncRefMsg: 2963 case MakeCollectable: 2964 llvm_unreachable("DecRefMsg/IncRefMsg/MakeCollectable already converted"); 2965 2966 case Dealloc: 2967 // Any use of -dealloc in GC is *bad*. 2968 if (C.isObjCGCEnabled()) { 2969 V = V ^ RefVal::ErrorDeallocGC; 2970 hasErr = V.getKind(); 2971 break; 2972 } 2973 2974 switch (V.getKind()) { 2975 default: 2976 llvm_unreachable("Invalid RefVal state for an explicit dealloc."); 2977 case RefVal::Owned: 2978 // The object immediately transitions to the released state. 2979 V = V ^ RefVal::Released; 2980 V.clearCounts(); 2981 return state->set<RefBindings>(sym, V); 2982 case RefVal::NotOwned: 2983 V = V ^ RefVal::ErrorDeallocNotOwned; 2984 hasErr = V.getKind(); 2985 break; 2986 } 2987 break; 2988 2989 case NewAutoreleasePool: 2990 assert(!C.isObjCGCEnabled()); 2991 return state->add<AutoreleaseStack>(sym); 2992 2993 case MayEscape: 2994 if (V.getKind() == RefVal::Owned) { 2995 V = V ^ RefVal::NotOwned; 2996 break; 2997 } 2998 2999 // Fall-through. 3000 3001 case DoNothing: 3002 return state; 3003 3004 case Autorelease: 3005 if (C.isObjCGCEnabled()) 3006 return state; 3007 3008 // Update the autorelease counts. 3009 state = SendAutorelease(state, ARCountFactory, sym); 3010 V = V.autorelease(); 3011 break; 3012 3013 case StopTracking: 3014 return state->remove<RefBindings>(sym); 3015 3016 case IncRef: 3017 switch (V.getKind()) { 3018 default: 3019 llvm_unreachable("Invalid RefVal state for a retain."); 3020 case RefVal::Owned: 3021 case RefVal::NotOwned: 3022 V = V + 1; 3023 break; 3024 case RefVal::Released: 3025 // Non-GC cases are handled above. 3026 assert(C.isObjCGCEnabled()); 3027 V = (V ^ RefVal::Owned) + 1; 3028 break; 3029 } 3030 break; 3031 3032 case DecRef: 3033 case DecRefBridgedTransfered: 3034 switch (V.getKind()) { 3035 default: 3036 // case 'RefVal::Released' handled above. 3037 llvm_unreachable("Invalid RefVal state for a release."); 3038 3039 case RefVal::Owned: 3040 assert(V.getCount() > 0); 3041 if (V.getCount() == 1) 3042 V = V ^ (E == DecRefBridgedTransfered ? 3043 RefVal::NotOwned : RefVal::Released); 3044 V = V - 1; 3045 break; 3046 3047 case RefVal::NotOwned: 3048 if (V.getCount() > 0) 3049 V = V - 1; 3050 else { 3051 V = V ^ RefVal::ErrorReleaseNotOwned; 3052 hasErr = V.getKind(); 3053 } 3054 break; 3055 3056 case RefVal::Released: 3057 // Non-GC cases are handled above. 3058 assert(C.isObjCGCEnabled()); 3059 V = V ^ RefVal::ErrorUseAfterRelease; 3060 hasErr = V.getKind(); 3061 break; 3062 } 3063 break; 3064 } 3065 return state->set<RefBindings>(sym, V); 3066} 3067 3068void RetainCountChecker::processNonLeakError(ProgramStateRef St, 3069 SourceRange ErrorRange, 3070 RefVal::Kind ErrorKind, 3071 SymbolRef Sym, 3072 CheckerContext &C) const { 3073 ExplodedNode *N = C.generateSink(St); 3074 if (!N) 3075 return; 3076 3077 CFRefBug *BT; 3078 switch (ErrorKind) { 3079 default: 3080 llvm_unreachable("Unhandled error."); 3081 case RefVal::ErrorUseAfterRelease: 3082 if (!useAfterRelease) 3083 useAfterRelease.reset(new UseAfterRelease()); 3084 BT = &*useAfterRelease; 3085 break; 3086 case RefVal::ErrorReleaseNotOwned: 3087 if (!releaseNotOwned) 3088 releaseNotOwned.reset(new BadRelease()); 3089 BT = &*releaseNotOwned; 3090 break; 3091 case RefVal::ErrorDeallocGC: 3092 if (!deallocGC) 3093 deallocGC.reset(new DeallocGC()); 3094 BT = &*deallocGC; 3095 break; 3096 case RefVal::ErrorDeallocNotOwned: 3097 if (!deallocNotOwned) 3098 deallocNotOwned.reset(new DeallocNotOwned()); 3099 BT = &*deallocNotOwned; 3100 break; 3101 } 3102 3103 assert(BT); 3104 CFRefReport *report = new CFRefReport(*BT, C.getASTContext().getLangOpts(), 3105 C.isObjCGCEnabled(), SummaryLog, 3106 N, Sym); 3107 report->addRange(ErrorRange); 3108 C.EmitReport(report); 3109} 3110 3111//===----------------------------------------------------------------------===// 3112// Handle the return values of retain-count-related functions. 3113//===----------------------------------------------------------------------===// 3114 3115bool RetainCountChecker::evalCall(const CallExpr *CE, CheckerContext &C) const { 3116 // Get the callee. We're only interested in simple C functions. 3117 ProgramStateRef state = C.getState(); 3118 const FunctionDecl *FD = C.getCalleeDecl(CE); 3119 if (!FD) 3120 return false; 3121 3122 IdentifierInfo *II = FD->getIdentifier(); 3123 if (!II) 3124 return false; 3125 3126 // For now, we're only handling the functions that return aliases of their 3127 // arguments: CFRetain and CFMakeCollectable (and their families). 3128 // Eventually we should add other functions we can model entirely, 3129 // such as CFRelease, which don't invalidate their arguments or globals. 3130 if (CE->getNumArgs() != 1) 3131 return false; 3132 3133 // Get the name of the function. 3134 StringRef FName = II->getName(); 3135 FName = FName.substr(FName.find_first_not_of('_')); 3136 3137 // See if it's one of the specific functions we know how to eval. 3138 bool canEval = false; 3139 3140 QualType ResultTy = CE->getCallReturnType(); 3141 if (ResultTy->isObjCIdType()) { 3142 // Handle: id NSMakeCollectable(CFTypeRef) 3143 canEval = II->isStr("NSMakeCollectable"); 3144 } else if (ResultTy->isPointerType()) { 3145 // Handle: (CF|CG)Retain 3146 // CFMakeCollectable 3147 // It's okay to be a little sloppy here (CGMakeCollectable doesn't exist). 3148 if (cocoa::isRefType(ResultTy, "CF", FName) || 3149 cocoa::isRefType(ResultTy, "CG", FName)) { 3150 canEval = isRetain(FD, FName) || isMakeCollectable(FD, FName); 3151 } 3152 } 3153 3154 if (!canEval) 3155 return false; 3156 3157 // Bind the return value. 3158 const LocationContext *LCtx = C.getLocationContext(); 3159 SVal RetVal = state->getSVal(CE->getArg(0), LCtx); 3160 if (RetVal.isUnknown()) { 3161 // If the receiver is unknown, conjure a return value. 3162 SValBuilder &SVB = C.getSValBuilder(); 3163 unsigned Count = C.getCurrentBlockCount(); 3164 SVal RetVal = SVB.getConjuredSymbolVal(0, CE, LCtx, ResultTy, Count); 3165 } 3166 state = state->BindExpr(CE, LCtx, RetVal, false); 3167 3168 // FIXME: This should not be necessary, but otherwise the argument seems to be 3169 // considered alive during the next statement. 3170 if (const MemRegion *ArgRegion = RetVal.getAsRegion()) { 3171 // Save the refcount status of the argument. 3172 SymbolRef Sym = RetVal.getAsLocSymbol(); 3173 RefBindings::data_type *Binding = 0; 3174 if (Sym) 3175 Binding = state->get<RefBindings>(Sym); 3176 3177 // Invalidate the argument region. 3178 unsigned Count = C.getCurrentBlockCount(); 3179 state = state->invalidateRegions(ArgRegion, CE, Count, LCtx); 3180 3181 // Restore the refcount status of the argument. 3182 if (Binding) 3183 state = state->set<RefBindings>(Sym, *Binding); 3184 } 3185 3186 C.addTransition(state); 3187 return true; 3188} 3189 3190//===----------------------------------------------------------------------===// 3191// Handle return statements. 3192//===----------------------------------------------------------------------===// 3193 3194// Return true if the current LocationContext has no caller context. 3195static bool inTopFrame(CheckerContext &C) { 3196 const LocationContext *LC = C.getLocationContext(); 3197 return LC->getParent() == 0; 3198} 3199 3200void RetainCountChecker::checkPreStmt(const ReturnStmt *S, 3201 CheckerContext &C) const { 3202 3203 // Only adjust the reference count if this is the top-level call frame, 3204 // and not the result of inlining. In the future, we should do 3205 // better checking even for inlined calls, and see if they match 3206 // with their expected semantics (e.g., the method should return a retained 3207 // object, etc.). 3208 if (!inTopFrame(C)) 3209 return; 3210 3211 const Expr *RetE = S->getRetValue(); 3212 if (!RetE) 3213 return; 3214 3215 ProgramStateRef state = C.getState(); 3216 SymbolRef Sym = 3217 state->getSValAsScalarOrLoc(RetE, C.getLocationContext()).getAsLocSymbol(); 3218 if (!Sym) 3219 return; 3220 3221 // Get the reference count binding (if any). 3222 const RefVal *T = state->get<RefBindings>(Sym); 3223 if (!T) 3224 return; 3225 3226 // Change the reference count. 3227 RefVal X = *T; 3228 3229 switch (X.getKind()) { 3230 case RefVal::Owned: { 3231 unsigned cnt = X.getCount(); 3232 assert(cnt > 0); 3233 X.setCount(cnt - 1); 3234 X = X ^ RefVal::ReturnedOwned; 3235 break; 3236 } 3237 3238 case RefVal::NotOwned: { 3239 unsigned cnt = X.getCount(); 3240 if (cnt) { 3241 X.setCount(cnt - 1); 3242 X = X ^ RefVal::ReturnedOwned; 3243 } 3244 else { 3245 X = X ^ RefVal::ReturnedNotOwned; 3246 } 3247 break; 3248 } 3249 3250 default: 3251 return; 3252 } 3253 3254 // Update the binding. 3255 state = state->set<RefBindings>(Sym, X); 3256 ExplodedNode *Pred = C.addTransition(state); 3257 3258 // At this point we have updated the state properly. 3259 // Everything after this is merely checking to see if the return value has 3260 // been over- or under-retained. 3261 3262 // Did we cache out? 3263 if (!Pred) 3264 return; 3265 3266 // Update the autorelease counts. 3267 static SimpleProgramPointTag 3268 AutoreleaseTag("RetainCountChecker : Autorelease"); 3269 GenericNodeBuilderRefCount Bd(C, &AutoreleaseTag); 3270 llvm::tie(Pred, state) = handleAutoreleaseCounts(state, Bd, Pred, C, Sym, X); 3271 3272 // Did we cache out? 3273 if (!Pred) 3274 return; 3275 3276 // Get the updated binding. 3277 T = state->get<RefBindings>(Sym); 3278 assert(T); 3279 X = *T; 3280 3281 // Consult the summary of the enclosing method. 3282 RetainSummaryManager &Summaries = getSummaryManager(C); 3283 const Decl *CD = &Pred->getCodeDecl(); 3284 3285 if (const ObjCMethodDecl *MD = dyn_cast<ObjCMethodDecl>(CD)) { 3286 // Unlike regular functions, /all/ ObjC methods are assumed to always 3287 // follow Cocoa retain-count conventions, not just those with special 3288 // names or attributes. 3289 const RetainSummary *Summ = Summaries.getMethodSummary(MD); 3290 RetEffect RE = Summ ? Summ->getRetEffect() : RetEffect::MakeNoRet(); 3291 checkReturnWithRetEffect(S, C, Pred, RE, X, Sym, state); 3292 } 3293 3294 if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(CD)) { 3295 if (!isa<CXXMethodDecl>(FD)) 3296 if (const RetainSummary *Summ = Summaries.getSummary(FD, 0)) 3297 checkReturnWithRetEffect(S, C, Pred, Summ->getRetEffect(), X, 3298 Sym, state); 3299 } 3300} 3301 3302void RetainCountChecker::checkReturnWithRetEffect(const ReturnStmt *S, 3303 CheckerContext &C, 3304 ExplodedNode *Pred, 3305 RetEffect RE, RefVal X, 3306 SymbolRef Sym, 3307 ProgramStateRef state) const { 3308 // Any leaks or other errors? 3309 if (X.isReturnedOwned() && X.getCount() == 0) { 3310 if (RE.getKind() != RetEffect::NoRet) { 3311 bool hasError = false; 3312 if (C.isObjCGCEnabled() && RE.getObjKind() == RetEffect::ObjC) { 3313 // Things are more complicated with garbage collection. If the 3314 // returned object is suppose to be an Objective-C object, we have 3315 // a leak (as the caller expects a GC'ed object) because no 3316 // method should return ownership unless it returns a CF object. 3317 hasError = true; 3318 X = X ^ RefVal::ErrorGCLeakReturned; 3319 } 3320 else if (!RE.isOwned()) { 3321 // Either we are using GC and the returned object is a CF type 3322 // or we aren't using GC. In either case, we expect that the 3323 // enclosing method is expected to return ownership. 3324 hasError = true; 3325 X = X ^ RefVal::ErrorLeakReturned; 3326 } 3327 3328 if (hasError) { 3329 // Generate an error node. 3330 state = state->set<RefBindings>(Sym, X); 3331 3332 static SimpleProgramPointTag 3333 ReturnOwnLeakTag("RetainCountChecker : ReturnsOwnLeak"); 3334 ExplodedNode *N = C.addTransition(state, Pred, &ReturnOwnLeakTag); 3335 if (N) { 3336 const LangOptions &LOpts = C.getASTContext().getLangOpts(); 3337 bool GCEnabled = C.isObjCGCEnabled(); 3338 CFRefReport *report = 3339 new CFRefLeakReport(*getLeakAtReturnBug(LOpts, GCEnabled), 3340 LOpts, GCEnabled, SummaryLog, 3341 N, Sym, C); 3342 C.EmitReport(report); 3343 } 3344 } 3345 } 3346 } else if (X.isReturnedNotOwned()) { 3347 if (RE.isOwned()) { 3348 // Trying to return a not owned object to a caller expecting an 3349 // owned object. 3350 state = state->set<RefBindings>(Sym, X ^ RefVal::ErrorReturnedNotOwned); 3351 3352 static SimpleProgramPointTag 3353 ReturnNotOwnedTag("RetainCountChecker : ReturnNotOwnedForOwned"); 3354 ExplodedNode *N = C.addTransition(state, Pred, &ReturnNotOwnedTag); 3355 if (N) { 3356 if (!returnNotOwnedForOwned) 3357 returnNotOwnedForOwned.reset(new ReturnedNotOwnedForOwned()); 3358 3359 CFRefReport *report = 3360 new CFRefReport(*returnNotOwnedForOwned, 3361 C.getASTContext().getLangOpts(), 3362 C.isObjCGCEnabled(), SummaryLog, N, Sym); 3363 C.EmitReport(report); 3364 } 3365 } 3366 } 3367} 3368 3369//===----------------------------------------------------------------------===// 3370// Check various ways a symbol can be invalidated. 3371//===----------------------------------------------------------------------===// 3372 3373void RetainCountChecker::checkBind(SVal loc, SVal val, const Stmt *S, 3374 CheckerContext &C) const { 3375 // Are we storing to something that causes the value to "escape"? 3376 bool escapes = true; 3377 3378 // A value escapes in three possible cases (this may change): 3379 // 3380 // (1) we are binding to something that is not a memory region. 3381 // (2) we are binding to a memregion that does not have stack storage 3382 // (3) we are binding to a memregion with stack storage that the store 3383 // does not understand. 3384 ProgramStateRef state = C.getState(); 3385 3386 if (loc::MemRegionVal *regionLoc = dyn_cast<loc::MemRegionVal>(&loc)) { 3387 escapes = !regionLoc->getRegion()->hasStackStorage(); 3388 3389 if (!escapes) { 3390 // To test (3), generate a new state with the binding added. If it is 3391 // the same state, then it escapes (since the store cannot represent 3392 // the binding). 3393 // Do this only if we know that the store is not supposed to generate the 3394 // same state. 3395 SVal StoredVal = state->getSVal(regionLoc->getRegion()); 3396 if (StoredVal != val) 3397 escapes = (state == (state->bindLoc(*regionLoc, val))); 3398 } 3399 if (!escapes) { 3400 // Case 4: We do not currently model what happens when a symbol is 3401 // assigned to a struct field, so be conservative here and let the symbol 3402 // go. TODO: This could definitely be improved upon. 3403 escapes = !isa<VarRegion>(regionLoc->getRegion()); 3404 } 3405 } 3406 3407 // If our store can represent the binding and we aren't storing to something 3408 // that doesn't have local storage then just return and have the simulation 3409 // state continue as is. 3410 if (!escapes) 3411 return; 3412 3413 // Otherwise, find all symbols referenced by 'val' that we are tracking 3414 // and stop tracking them. 3415 state = state->scanReachableSymbols<StopTrackingCallback>(val).getState(); 3416 C.addTransition(state); 3417} 3418 3419ProgramStateRef RetainCountChecker::evalAssume(ProgramStateRef state, 3420 SVal Cond, 3421 bool Assumption) const { 3422 3423 // FIXME: We may add to the interface of evalAssume the list of symbols 3424 // whose assumptions have changed. For now we just iterate through the 3425 // bindings and check if any of the tracked symbols are NULL. This isn't 3426 // too bad since the number of symbols we will track in practice are 3427 // probably small and evalAssume is only called at branches and a few 3428 // other places. 3429 RefBindings B = state->get<RefBindings>(); 3430 3431 if (B.isEmpty()) 3432 return state; 3433 3434 bool changed = false; 3435 RefBindings::Factory &RefBFactory = state->get_context<RefBindings>(); 3436 3437 for (RefBindings::iterator I = B.begin(), E = B.end(); I != E; ++I) { 3438 // Check if the symbol is null (or equal to any constant). 3439 // If this is the case, stop tracking the symbol. 3440 if (state->getSymVal(I.getKey())) { 3441 changed = true; 3442 B = RefBFactory.remove(B, I.getKey()); 3443 } 3444 } 3445 3446 if (changed) 3447 state = state->set<RefBindings>(B); 3448 3449 return state; 3450} 3451 3452ProgramStateRef 3453RetainCountChecker::checkRegionChanges(ProgramStateRef state, 3454 const StoreManager::InvalidatedSymbols *invalidated, 3455 ArrayRef<const MemRegion *> ExplicitRegions, 3456 ArrayRef<const MemRegion *> Regions, 3457 const CallEvent *Call) const { 3458 if (!invalidated) 3459 return state; 3460 3461 llvm::SmallPtrSet<SymbolRef, 8> WhitelistedSymbols; 3462 for (ArrayRef<const MemRegion *>::iterator I = ExplicitRegions.begin(), 3463 E = ExplicitRegions.end(); I != E; ++I) { 3464 if (const SymbolicRegion *SR = (*I)->StripCasts()->getAs<SymbolicRegion>()) 3465 WhitelistedSymbols.insert(SR->getSymbol()); 3466 } 3467 3468 for (StoreManager::InvalidatedSymbols::const_iterator I=invalidated->begin(), 3469 E = invalidated->end(); I!=E; ++I) { 3470 SymbolRef sym = *I; 3471 if (WhitelistedSymbols.count(sym)) 3472 continue; 3473 // Remove any existing reference-count binding. 3474 state = state->remove<RefBindings>(sym); 3475 } 3476 return state; 3477} 3478 3479//===----------------------------------------------------------------------===// 3480// Handle dead symbols and end-of-path. 3481//===----------------------------------------------------------------------===// 3482 3483std::pair<ExplodedNode *, ProgramStateRef > 3484RetainCountChecker::handleAutoreleaseCounts(ProgramStateRef state, 3485 GenericNodeBuilderRefCount Bd, 3486 ExplodedNode *Pred, 3487 CheckerContext &Ctx, 3488 SymbolRef Sym, RefVal V) const { 3489 unsigned ACnt = V.getAutoreleaseCount(); 3490 3491 // No autorelease counts? Nothing to be done. 3492 if (!ACnt) 3493 return std::make_pair(Pred, state); 3494 3495 assert(!Ctx.isObjCGCEnabled() && "Autorelease counts in GC mode?"); 3496 unsigned Cnt = V.getCount(); 3497 3498 // FIXME: Handle sending 'autorelease' to already released object. 3499 3500 if (V.getKind() == RefVal::ReturnedOwned) 3501 ++Cnt; 3502 3503 if (ACnt <= Cnt) { 3504 if (ACnt == Cnt) { 3505 V.clearCounts(); 3506 if (V.getKind() == RefVal::ReturnedOwned) 3507 V = V ^ RefVal::ReturnedNotOwned; 3508 else 3509 V = V ^ RefVal::NotOwned; 3510 } else { 3511 V.setCount(Cnt - ACnt); 3512 V.setAutoreleaseCount(0); 3513 } 3514 state = state->set<RefBindings>(Sym, V); 3515 ExplodedNode *N = Bd.MakeNode(state, Pred); 3516 if (N == 0) 3517 state = 0; 3518 return std::make_pair(N, state); 3519 } 3520 3521 // Woah! More autorelease counts then retain counts left. 3522 // Emit hard error. 3523 V = V ^ RefVal::ErrorOverAutorelease; 3524 state = state->set<RefBindings>(Sym, V); 3525 3526 if (ExplodedNode *N = Bd.MakeNode(state, Pred, true)) { 3527 SmallString<128> sbuf; 3528 llvm::raw_svector_ostream os(sbuf); 3529 os << "Object over-autoreleased: object was sent -autorelease "; 3530 if (V.getAutoreleaseCount() > 1) 3531 os << V.getAutoreleaseCount() << " times "; 3532 os << "but the object has a +" << V.getCount() << " retain count"; 3533 3534 if (!overAutorelease) 3535 overAutorelease.reset(new OverAutorelease()); 3536 3537 const LangOptions &LOpts = Ctx.getASTContext().getLangOpts(); 3538 CFRefReport *report = 3539 new CFRefReport(*overAutorelease, LOpts, /* GCEnabled = */ false, 3540 SummaryLog, N, Sym, os.str()); 3541 Ctx.EmitReport(report); 3542 } 3543 3544 return std::make_pair((ExplodedNode *)0, (ProgramStateRef )0); 3545} 3546 3547ProgramStateRef 3548RetainCountChecker::handleSymbolDeath(ProgramStateRef state, 3549 SymbolRef sid, RefVal V, 3550 SmallVectorImpl<SymbolRef> &Leaked) const { 3551 bool hasLeak = false; 3552 if (V.isOwned()) 3553 hasLeak = true; 3554 else if (V.isNotOwned() || V.isReturnedOwned()) 3555 hasLeak = (V.getCount() > 0); 3556 3557 if (!hasLeak) 3558 return state->remove<RefBindings>(sid); 3559 3560 Leaked.push_back(sid); 3561 return state->set<RefBindings>(sid, V ^ RefVal::ErrorLeak); 3562} 3563 3564ExplodedNode * 3565RetainCountChecker::processLeaks(ProgramStateRef state, 3566 SmallVectorImpl<SymbolRef> &Leaked, 3567 GenericNodeBuilderRefCount &Builder, 3568 CheckerContext &Ctx, 3569 ExplodedNode *Pred) const { 3570 if (Leaked.empty()) 3571 return Pred; 3572 3573 // Generate an intermediate node representing the leak point. 3574 ExplodedNode *N = Builder.MakeNode(state, Pred); 3575 3576 if (N) { 3577 for (SmallVectorImpl<SymbolRef>::iterator 3578 I = Leaked.begin(), E = Leaked.end(); I != E; ++I) { 3579 3580 const LangOptions &LOpts = Ctx.getASTContext().getLangOpts(); 3581 bool GCEnabled = Ctx.isObjCGCEnabled(); 3582 CFRefBug *BT = Pred ? getLeakWithinFunctionBug(LOpts, GCEnabled) 3583 : getLeakAtReturnBug(LOpts, GCEnabled); 3584 assert(BT && "BugType not initialized."); 3585 3586 CFRefLeakReport *report = new CFRefLeakReport(*BT, LOpts, GCEnabled, 3587 SummaryLog, N, *I, Ctx); 3588 Ctx.EmitReport(report); 3589 } 3590 } 3591 3592 return N; 3593} 3594 3595void RetainCountChecker::checkEndPath(CheckerContext &Ctx) const { 3596 ProgramStateRef state = Ctx.getState(); 3597 GenericNodeBuilderRefCount Bd(Ctx); 3598 RefBindings B = state->get<RefBindings>(); 3599 ExplodedNode *Pred = Ctx.getPredecessor(); 3600 3601 for (RefBindings::iterator I = B.begin(), E = B.end(); I != E; ++I) { 3602 llvm::tie(Pred, state) = handleAutoreleaseCounts(state, Bd, Pred, Ctx, 3603 I->first, I->second); 3604 if (!state) 3605 return; 3606 } 3607 3608 // If the current LocationContext has a parent, don't check for leaks. 3609 // We will do that later. 3610 // FIXME: we should instead check for imblances of the retain/releases, 3611 // and suggest annotations. 3612 if (Ctx.getLocationContext()->getParent()) 3613 return; 3614 3615 B = state->get<RefBindings>(); 3616 SmallVector<SymbolRef, 10> Leaked; 3617 3618 for (RefBindings::iterator I = B.begin(), E = B.end(); I != E; ++I) 3619 state = handleSymbolDeath(state, I->first, I->second, Leaked); 3620 3621 processLeaks(state, Leaked, Bd, Ctx, Pred); 3622} 3623 3624const ProgramPointTag * 3625RetainCountChecker::getDeadSymbolTag(SymbolRef sym) const { 3626 const SimpleProgramPointTag *&tag = DeadSymbolTags[sym]; 3627 if (!tag) { 3628 SmallString<64> buf; 3629 llvm::raw_svector_ostream out(buf); 3630 out << "RetainCountChecker : Dead Symbol : "; 3631 sym->dumpToStream(out); 3632 tag = new SimpleProgramPointTag(out.str()); 3633 } 3634 return tag; 3635} 3636 3637void RetainCountChecker::checkDeadSymbols(SymbolReaper &SymReaper, 3638 CheckerContext &C) const { 3639 ExplodedNode *Pred = C.getPredecessor(); 3640 3641 ProgramStateRef state = C.getState(); 3642 RefBindings B = state->get<RefBindings>(); 3643 3644 // Update counts from autorelease pools 3645 for (SymbolReaper::dead_iterator I = SymReaper.dead_begin(), 3646 E = SymReaper.dead_end(); I != E; ++I) { 3647 SymbolRef Sym = *I; 3648 if (const RefVal *T = B.lookup(Sym)){ 3649 // Use the symbol as the tag. 3650 // FIXME: This might not be as unique as we would like. 3651 GenericNodeBuilderRefCount Bd(C, getDeadSymbolTag(Sym)); 3652 llvm::tie(Pred, state) = handleAutoreleaseCounts(state, Bd, Pred, C, 3653 Sym, *T); 3654 if (!state) 3655 return; 3656 } 3657 } 3658 3659 B = state->get<RefBindings>(); 3660 SmallVector<SymbolRef, 10> Leaked; 3661 3662 for (SymbolReaper::dead_iterator I = SymReaper.dead_begin(), 3663 E = SymReaper.dead_end(); I != E; ++I) { 3664 if (const RefVal *T = B.lookup(*I)) 3665 state = handleSymbolDeath(state, *I, *T, Leaked); 3666 } 3667 3668 { 3669 GenericNodeBuilderRefCount Bd(C, this); 3670 Pred = processLeaks(state, Leaked, Bd, C, Pred); 3671 } 3672 3673 // Did we cache out? 3674 if (!Pred) 3675 return; 3676 3677 // Now generate a new node that nukes the old bindings. 3678 RefBindings::Factory &F = state->get_context<RefBindings>(); 3679 3680 for (SymbolReaper::dead_iterator I = SymReaper.dead_begin(), 3681 E = SymReaper.dead_end(); I != E; ++I) 3682 B = F.remove(B, *I); 3683 3684 state = state->set<RefBindings>(B); 3685 C.addTransition(state, Pred); 3686} 3687 3688//===----------------------------------------------------------------------===// 3689// Debug printing of refcount bindings and autorelease pools. 3690//===----------------------------------------------------------------------===// 3691 3692static void PrintPool(raw_ostream &Out, SymbolRef Sym, 3693 ProgramStateRef State) { 3694 Out << ' '; 3695 if (Sym) 3696 Sym->dumpToStream(Out); 3697 else 3698 Out << "<pool>"; 3699 Out << ":{"; 3700 3701 // Get the contents of the pool. 3702 if (const ARCounts *Cnts = State->get<AutoreleasePoolContents>(Sym)) 3703 for (ARCounts::iterator I = Cnts->begin(), E = Cnts->end(); I != E; ++I) 3704 Out << '(' << I.getKey() << ',' << I.getData() << ')'; 3705 3706 Out << '}'; 3707} 3708 3709static bool UsesAutorelease(ProgramStateRef state) { 3710 // A state uses autorelease if it allocated an autorelease pool or if it has 3711 // objects in the caller's autorelease pool. 3712 return !state->get<AutoreleaseStack>().isEmpty() || 3713 state->get<AutoreleasePoolContents>(SymbolRef()); 3714} 3715 3716void RetainCountChecker::printState(raw_ostream &Out, ProgramStateRef State, 3717 const char *NL, const char *Sep) const { 3718 3719 RefBindings B = State->get<RefBindings>(); 3720 3721 if (!B.isEmpty()) 3722 Out << Sep << NL; 3723 3724 for (RefBindings::iterator I = B.begin(), E = B.end(); I != E; ++I) { 3725 Out << I->first << " : "; 3726 I->second.print(Out); 3727 Out << NL; 3728 } 3729 3730 // Print the autorelease stack. 3731 if (UsesAutorelease(State)) { 3732 Out << Sep << NL << "AR pool stack:"; 3733 ARStack Stack = State->get<AutoreleaseStack>(); 3734 3735 PrintPool(Out, SymbolRef(), State); // Print the caller's pool. 3736 for (ARStack::iterator I = Stack.begin(), E = Stack.end(); I != E; ++I) 3737 PrintPool(Out, *I, State); 3738 3739 Out << NL; 3740 } 3741} 3742 3743//===----------------------------------------------------------------------===// 3744// Checker registration. 3745//===----------------------------------------------------------------------===// 3746 3747void ento::registerRetainCountChecker(CheckerManager &Mgr) { 3748 Mgr.registerChecker<RetainCountChecker>(); 3749} 3750 3751