RetainCountChecker.cpp revision 66c40400e7d6272b0cd675ada18dd62c1f0362c7
1//==-- RetainCountChecker.cpp - Checks for leaks and other issues -*- C++ -*--// 2// 3// The LLVM Compiler Infrastructure 4// 5// This file is distributed under the University of Illinois Open Source 6// License. See LICENSE.TXT for details. 7// 8//===----------------------------------------------------------------------===// 9// 10// This file defines the methods for RetainCountChecker, which implements 11// a reference count checker for Core Foundation and Cocoa on (Mac OS X). 12// 13//===----------------------------------------------------------------------===// 14 15#include "ClangSACheckers.h" 16#include "clang/AST/DeclObjC.h" 17#include "clang/AST/DeclCXX.h" 18#include "clang/Basic/LangOptions.h" 19#include "clang/Basic/SourceManager.h" 20#include "clang/Analysis/DomainSpecific/CocoaConventions.h" 21#include "clang/AST/ParentMap.h" 22#include "clang/StaticAnalyzer/Core/Checker.h" 23#include "clang/StaticAnalyzer/Core/CheckerManager.h" 24#include "clang/StaticAnalyzer/Core/BugReporter/BugType.h" 25#include "clang/StaticAnalyzer/Core/BugReporter/PathDiagnostic.h" 26#include "clang/StaticAnalyzer/Core/PathSensitive/CheckerContext.h" 27#include "clang/StaticAnalyzer/Core/PathSensitive/ProgramStateTrait.h" 28#include "clang/StaticAnalyzer/Core/PathSensitive/SymbolManager.h" 29#include "clang/StaticAnalyzer/Core/PathSensitive/ObjCMessage.h" 30#include "llvm/ADT/DenseMap.h" 31#include "llvm/ADT/FoldingSet.h" 32#include "llvm/ADT/ImmutableList.h" 33#include "llvm/ADT/ImmutableMap.h" 34#include "llvm/ADT/SmallString.h" 35#include "llvm/ADT/STLExtras.h" 36#include "llvm/ADT/StringExtras.h" 37#include <cstdarg> 38 39using namespace clang; 40using namespace ento; 41using llvm::StrInStrNoCase; 42 43namespace { 44/// Wrapper around different kinds of node builder, so that helper functions 45/// can have a common interface. 46class GenericNodeBuilderRefCount { 47 CheckerContext *C; 48 const ProgramPointTag *tag; 49public: 50 GenericNodeBuilderRefCount(CheckerContext &c, 51 const ProgramPointTag *t = 0) 52 : C(&c), tag(t){} 53 54 ExplodedNode *MakeNode(ProgramStateRef state, ExplodedNode *Pred, 55 bool MarkAsSink = false) { 56 return C->addTransition(state, Pred, tag, MarkAsSink); 57 } 58}; 59} // end anonymous namespace 60 61//===----------------------------------------------------------------------===// 62// Primitives used for constructing summaries for function/method calls. 63//===----------------------------------------------------------------------===// 64 65/// ArgEffect is used to summarize a function/method call's effect on a 66/// particular argument. 67enum ArgEffect { DoNothing, Autorelease, Dealloc, DecRef, DecRefMsg, 68 DecRefBridgedTransfered, 69 IncRefMsg, IncRef, MakeCollectable, MayEscape, 70 NewAutoreleasePool, SelfOwn, StopTracking }; 71 72namespace llvm { 73template <> struct FoldingSetTrait<ArgEffect> { 74static inline void Profile(const ArgEffect X, FoldingSetNodeID& ID) { 75 ID.AddInteger((unsigned) X); 76} 77}; 78} // end llvm namespace 79 80/// ArgEffects summarizes the effects of a function/method call on all of 81/// its arguments. 82typedef llvm::ImmutableMap<unsigned,ArgEffect> ArgEffects; 83 84namespace { 85 86/// RetEffect is used to summarize a function/method call's behavior with 87/// respect to its return value. 88class RetEffect { 89public: 90 enum Kind { NoRet, OwnedSymbol, OwnedAllocatedSymbol, 91 NotOwnedSymbol, GCNotOwnedSymbol, ARCNotOwnedSymbol, 92 OwnedWhenTrackedReceiver }; 93 94 enum ObjKind { CF, ObjC, AnyObj }; 95 96private: 97 Kind K; 98 ObjKind O; 99 100 RetEffect(Kind k, ObjKind o = AnyObj) : K(k), O(o) {} 101 102public: 103 Kind getKind() const { return K; } 104 105 ObjKind getObjKind() const { return O; } 106 107 bool isOwned() const { 108 return K == OwnedSymbol || K == OwnedAllocatedSymbol || 109 K == OwnedWhenTrackedReceiver; 110 } 111 112 bool operator==(const RetEffect &Other) const { 113 return K == Other.K && O == Other.O; 114 } 115 116 static RetEffect MakeOwnedWhenTrackedReceiver() { 117 return RetEffect(OwnedWhenTrackedReceiver, ObjC); 118 } 119 120 static RetEffect MakeOwned(ObjKind o, bool isAllocated = false) { 121 return RetEffect(isAllocated ? OwnedAllocatedSymbol : OwnedSymbol, o); 122 } 123 static RetEffect MakeNotOwned(ObjKind o) { 124 return RetEffect(NotOwnedSymbol, o); 125 } 126 static RetEffect MakeGCNotOwned() { 127 return RetEffect(GCNotOwnedSymbol, ObjC); 128 } 129 static RetEffect MakeARCNotOwned() { 130 return RetEffect(ARCNotOwnedSymbol, ObjC); 131 } 132 static RetEffect MakeNoRet() { 133 return RetEffect(NoRet); 134 } 135}; 136 137//===----------------------------------------------------------------------===// 138// Reference-counting logic (typestate + counts). 139//===----------------------------------------------------------------------===// 140 141class RefVal { 142public: 143 enum Kind { 144 Owned = 0, // Owning reference. 145 NotOwned, // Reference is not owned by still valid (not freed). 146 Released, // Object has been released. 147 ReturnedOwned, // Returned object passes ownership to caller. 148 ReturnedNotOwned, // Return object does not pass ownership to caller. 149 ERROR_START, 150 ErrorDeallocNotOwned, // -dealloc called on non-owned object. 151 ErrorDeallocGC, // Calling -dealloc with GC enabled. 152 ErrorUseAfterRelease, // Object used after released. 153 ErrorReleaseNotOwned, // Release of an object that was not owned. 154 ERROR_LEAK_START, 155 ErrorLeak, // A memory leak due to excessive reference counts. 156 ErrorLeakReturned, // A memory leak due to the returning method not having 157 // the correct naming conventions. 158 ErrorGCLeakReturned, 159 ErrorOverAutorelease, 160 ErrorReturnedNotOwned 161 }; 162 163private: 164 Kind kind; 165 RetEffect::ObjKind okind; 166 unsigned Cnt; 167 unsigned ACnt; 168 QualType T; 169 170 RefVal(Kind k, RetEffect::ObjKind o, unsigned cnt, unsigned acnt, QualType t) 171 : kind(k), okind(o), Cnt(cnt), ACnt(acnt), T(t) {} 172 173public: 174 Kind getKind() const { return kind; } 175 176 RetEffect::ObjKind getObjKind() const { return okind; } 177 178 unsigned getCount() const { return Cnt; } 179 unsigned getAutoreleaseCount() const { return ACnt; } 180 unsigned getCombinedCounts() const { return Cnt + ACnt; } 181 void clearCounts() { Cnt = 0; ACnt = 0; } 182 void setCount(unsigned i) { Cnt = i; } 183 void setAutoreleaseCount(unsigned i) { ACnt = i; } 184 185 QualType getType() const { return T; } 186 187 bool isOwned() const { 188 return getKind() == Owned; 189 } 190 191 bool isNotOwned() const { 192 return getKind() == NotOwned; 193 } 194 195 bool isReturnedOwned() const { 196 return getKind() == ReturnedOwned; 197 } 198 199 bool isReturnedNotOwned() const { 200 return getKind() == ReturnedNotOwned; 201 } 202 203 static RefVal makeOwned(RetEffect::ObjKind o, QualType t, 204 unsigned Count = 1) { 205 return RefVal(Owned, o, Count, 0, t); 206 } 207 208 static RefVal makeNotOwned(RetEffect::ObjKind o, QualType t, 209 unsigned Count = 0) { 210 return RefVal(NotOwned, o, Count, 0, t); 211 } 212 213 // Comparison, profiling, and pretty-printing. 214 215 bool operator==(const RefVal& X) const { 216 return kind == X.kind && Cnt == X.Cnt && T == X.T && ACnt == X.ACnt; 217 } 218 219 RefVal operator-(size_t i) const { 220 return RefVal(getKind(), getObjKind(), getCount() - i, 221 getAutoreleaseCount(), getType()); 222 } 223 224 RefVal operator+(size_t i) const { 225 return RefVal(getKind(), getObjKind(), getCount() + i, 226 getAutoreleaseCount(), getType()); 227 } 228 229 RefVal operator^(Kind k) const { 230 return RefVal(k, getObjKind(), getCount(), getAutoreleaseCount(), 231 getType()); 232 } 233 234 RefVal autorelease() const { 235 return RefVal(getKind(), getObjKind(), getCount(), getAutoreleaseCount()+1, 236 getType()); 237 } 238 239 void Profile(llvm::FoldingSetNodeID& ID) const { 240 ID.AddInteger((unsigned) kind); 241 ID.AddInteger(Cnt); 242 ID.AddInteger(ACnt); 243 ID.Add(T); 244 } 245 246 void print(raw_ostream &Out) const; 247}; 248 249void RefVal::print(raw_ostream &Out) const { 250 if (!T.isNull()) 251 Out << "Tracked " << T.getAsString() << '/'; 252 253 switch (getKind()) { 254 default: llvm_unreachable("Invalid RefVal kind"); 255 case Owned: { 256 Out << "Owned"; 257 unsigned cnt = getCount(); 258 if (cnt) Out << " (+ " << cnt << ")"; 259 break; 260 } 261 262 case NotOwned: { 263 Out << "NotOwned"; 264 unsigned cnt = getCount(); 265 if (cnt) Out << " (+ " << cnt << ")"; 266 break; 267 } 268 269 case ReturnedOwned: { 270 Out << "ReturnedOwned"; 271 unsigned cnt = getCount(); 272 if (cnt) Out << " (+ " << cnt << ")"; 273 break; 274 } 275 276 case ReturnedNotOwned: { 277 Out << "ReturnedNotOwned"; 278 unsigned cnt = getCount(); 279 if (cnt) Out << " (+ " << cnt << ")"; 280 break; 281 } 282 283 case Released: 284 Out << "Released"; 285 break; 286 287 case ErrorDeallocGC: 288 Out << "-dealloc (GC)"; 289 break; 290 291 case ErrorDeallocNotOwned: 292 Out << "-dealloc (not-owned)"; 293 break; 294 295 case ErrorLeak: 296 Out << "Leaked"; 297 break; 298 299 case ErrorLeakReturned: 300 Out << "Leaked (Bad naming)"; 301 break; 302 303 case ErrorGCLeakReturned: 304 Out << "Leaked (GC-ed at return)"; 305 break; 306 307 case ErrorUseAfterRelease: 308 Out << "Use-After-Release [ERROR]"; 309 break; 310 311 case ErrorReleaseNotOwned: 312 Out << "Release of Not-Owned [ERROR]"; 313 break; 314 315 case RefVal::ErrorOverAutorelease: 316 Out << "Over autoreleased"; 317 break; 318 319 case RefVal::ErrorReturnedNotOwned: 320 Out << "Non-owned object returned instead of owned"; 321 break; 322 } 323 324 if (ACnt) { 325 Out << " [ARC +" << ACnt << ']'; 326 } 327} 328} //end anonymous namespace 329 330//===----------------------------------------------------------------------===// 331// RefBindings - State used to track object reference counts. 332//===----------------------------------------------------------------------===// 333 334typedef llvm::ImmutableMap<SymbolRef, RefVal> RefBindings; 335 336namespace clang { 337namespace ento { 338template<> 339struct ProgramStateTrait<RefBindings> 340 : public ProgramStatePartialTrait<RefBindings> { 341 static void *GDMIndex() { 342 static int RefBIndex = 0; 343 return &RefBIndex; 344 } 345}; 346} 347} 348 349//===----------------------------------------------------------------------===// 350// Function/Method behavior summaries. 351//===----------------------------------------------------------------------===// 352 353namespace { 354class RetainSummary { 355 /// Args - an ordered vector of (index, ArgEffect) pairs, where index 356 /// specifies the argument (starting from 0). This can be sparsely 357 /// populated; arguments with no entry in Args use 'DefaultArgEffect'. 358 ArgEffects Args; 359 360 /// DefaultArgEffect - The default ArgEffect to apply to arguments that 361 /// do not have an entry in Args. 362 ArgEffect DefaultArgEffect; 363 364 /// Receiver - If this summary applies to an Objective-C message expression, 365 /// this is the effect applied to the state of the receiver. 366 ArgEffect Receiver; 367 368 /// Ret - The effect on the return value. Used to indicate if the 369 /// function/method call returns a new tracked symbol. 370 RetEffect Ret; 371 372public: 373 RetainSummary(ArgEffects A, RetEffect R, ArgEffect defaultEff, 374 ArgEffect ReceiverEff) 375 : Args(A), DefaultArgEffect(defaultEff), Receiver(ReceiverEff), Ret(R) {} 376 377 /// getArg - Return the argument effect on the argument specified by 378 /// idx (starting from 0). 379 ArgEffect getArg(unsigned idx) const { 380 if (const ArgEffect *AE = Args.lookup(idx)) 381 return *AE; 382 383 return DefaultArgEffect; 384 } 385 386 void addArg(ArgEffects::Factory &af, unsigned idx, ArgEffect e) { 387 Args = af.add(Args, idx, e); 388 } 389 390 /// setDefaultArgEffect - Set the default argument effect. 391 void setDefaultArgEffect(ArgEffect E) { 392 DefaultArgEffect = E; 393 } 394 395 /// getRetEffect - Returns the effect on the return value of the call. 396 RetEffect getRetEffect() const { return Ret; } 397 398 /// setRetEffect - Set the effect of the return value of the call. 399 void setRetEffect(RetEffect E) { Ret = E; } 400 401 402 /// Sets the effect on the receiver of the message. 403 void setReceiverEffect(ArgEffect e) { Receiver = e; } 404 405 /// getReceiverEffect - Returns the effect on the receiver of the call. 406 /// This is only meaningful if the summary applies to an ObjCMessageExpr*. 407 ArgEffect getReceiverEffect() const { return Receiver; } 408 409 /// Test if two retain summaries are identical. Note that merely equivalent 410 /// summaries are not necessarily identical (for example, if an explicit 411 /// argument effect matches the default effect). 412 bool operator==(const RetainSummary &Other) const { 413 return Args == Other.Args && DefaultArgEffect == Other.DefaultArgEffect && 414 Receiver == Other.Receiver && Ret == Other.Ret; 415 } 416}; 417} // end anonymous namespace 418 419//===----------------------------------------------------------------------===// 420// Data structures for constructing summaries. 421//===----------------------------------------------------------------------===// 422 423namespace { 424class ObjCSummaryKey { 425 IdentifierInfo* II; 426 Selector S; 427public: 428 ObjCSummaryKey(IdentifierInfo* ii, Selector s) 429 : II(ii), S(s) {} 430 431 ObjCSummaryKey(const ObjCInterfaceDecl *d, Selector s) 432 : II(d ? d->getIdentifier() : 0), S(s) {} 433 434 ObjCSummaryKey(const ObjCInterfaceDecl *d, IdentifierInfo *ii, Selector s) 435 : II(d ? d->getIdentifier() : ii), S(s) {} 436 437 ObjCSummaryKey(Selector s) 438 : II(0), S(s) {} 439 440 IdentifierInfo *getIdentifier() const { return II; } 441 Selector getSelector() const { return S; } 442}; 443} 444 445namespace llvm { 446template <> struct DenseMapInfo<ObjCSummaryKey> { 447 static inline ObjCSummaryKey getEmptyKey() { 448 return ObjCSummaryKey(DenseMapInfo<IdentifierInfo*>::getEmptyKey(), 449 DenseMapInfo<Selector>::getEmptyKey()); 450 } 451 452 static inline ObjCSummaryKey getTombstoneKey() { 453 return ObjCSummaryKey(DenseMapInfo<IdentifierInfo*>::getTombstoneKey(), 454 DenseMapInfo<Selector>::getTombstoneKey()); 455 } 456 457 static unsigned getHashValue(const ObjCSummaryKey &V) { 458 return (DenseMapInfo<IdentifierInfo*>::getHashValue(V.getIdentifier()) 459 & 0x88888888) 460 | (DenseMapInfo<Selector>::getHashValue(V.getSelector()) 461 & 0x55555555); 462 } 463 464 static bool isEqual(const ObjCSummaryKey& LHS, const ObjCSummaryKey& RHS) { 465 return DenseMapInfo<IdentifierInfo*>::isEqual(LHS.getIdentifier(), 466 RHS.getIdentifier()) && 467 DenseMapInfo<Selector>::isEqual(LHS.getSelector(), 468 RHS.getSelector()); 469 } 470 471}; 472template <> 473struct isPodLike<ObjCSummaryKey> { static const bool value = true; }; 474} // end llvm namespace 475 476namespace { 477class ObjCSummaryCache { 478 typedef llvm::DenseMap<ObjCSummaryKey, const RetainSummary *> MapTy; 479 MapTy M; 480public: 481 ObjCSummaryCache() {} 482 483 const RetainSummary * find(const ObjCInterfaceDecl *D, IdentifierInfo *ClsName, 484 Selector S) { 485 // Lookup the method using the decl for the class @interface. If we 486 // have no decl, lookup using the class name. 487 return D ? find(D, S) : find(ClsName, S); 488 } 489 490 const RetainSummary * find(const ObjCInterfaceDecl *D, Selector S) { 491 // Do a lookup with the (D,S) pair. If we find a match return 492 // the iterator. 493 ObjCSummaryKey K(D, S); 494 MapTy::iterator I = M.find(K); 495 496 if (I != M.end() || !D) 497 return I->second; 498 499 // Walk the super chain. If we find a hit with a parent, we'll end 500 // up returning that summary. We actually allow that key (null,S), as 501 // we cache summaries for the null ObjCInterfaceDecl* to allow us to 502 // generate initial summaries without having to worry about NSObject 503 // being declared. 504 // FIXME: We may change this at some point. 505 for (ObjCInterfaceDecl *C=D->getSuperClass() ;; C=C->getSuperClass()) { 506 if ((I = M.find(ObjCSummaryKey(C, S))) != M.end()) 507 break; 508 509 if (!C) 510 return NULL; 511 } 512 513 // Cache the summary with original key to make the next lookup faster 514 // and return the iterator. 515 const RetainSummary *Summ = I->second; 516 M[K] = Summ; 517 return Summ; 518 } 519 520 const RetainSummary *find(IdentifierInfo* II, Selector S) { 521 // FIXME: Class method lookup. Right now we dont' have a good way 522 // of going between IdentifierInfo* and the class hierarchy. 523 MapTy::iterator I = M.find(ObjCSummaryKey(II, S)); 524 525 if (I == M.end()) 526 I = M.find(ObjCSummaryKey(S)); 527 528 return I == M.end() ? NULL : I->second; 529 } 530 531 const RetainSummary *& operator[](ObjCSummaryKey K) { 532 return M[K]; 533 } 534 535 const RetainSummary *& operator[](Selector S) { 536 return M[ ObjCSummaryKey(S) ]; 537 } 538}; 539} // end anonymous namespace 540 541//===----------------------------------------------------------------------===// 542// Data structures for managing collections of summaries. 543//===----------------------------------------------------------------------===// 544 545namespace { 546class RetainSummaryManager { 547 548 //==-----------------------------------------------------------------==// 549 // Typedefs. 550 //==-----------------------------------------------------------------==// 551 552 typedef llvm::DenseMap<const FunctionDecl*, const RetainSummary *> 553 FuncSummariesTy; 554 555 typedef ObjCSummaryCache ObjCMethodSummariesTy; 556 557 //==-----------------------------------------------------------------==// 558 // Data. 559 //==-----------------------------------------------------------------==// 560 561 /// Ctx - The ASTContext object for the analyzed ASTs. 562 ASTContext &Ctx; 563 564 /// GCEnabled - Records whether or not the analyzed code runs in GC mode. 565 const bool GCEnabled; 566 567 /// Records whether or not the analyzed code runs in ARC mode. 568 const bool ARCEnabled; 569 570 /// FuncSummaries - A map from FunctionDecls to summaries. 571 FuncSummariesTy FuncSummaries; 572 573 /// ObjCClassMethodSummaries - A map from selectors (for instance methods) 574 /// to summaries. 575 ObjCMethodSummariesTy ObjCClassMethodSummaries; 576 577 /// ObjCMethodSummaries - A map from selectors to summaries. 578 ObjCMethodSummariesTy ObjCMethodSummaries; 579 580 /// BPAlloc - A BumpPtrAllocator used for allocating summaries, ArgEffects, 581 /// and all other data used by the checker. 582 llvm::BumpPtrAllocator BPAlloc; 583 584 /// AF - A factory for ArgEffects objects. 585 ArgEffects::Factory AF; 586 587 /// ScratchArgs - A holding buffer for construct ArgEffects. 588 ArgEffects ScratchArgs; 589 590 /// ObjCAllocRetE - Default return effect for methods returning Objective-C 591 /// objects. 592 RetEffect ObjCAllocRetE; 593 594 /// ObjCInitRetE - Default return effect for init methods returning 595 /// Objective-C objects. 596 RetEffect ObjCInitRetE; 597 598 RetainSummary DefaultSummary; 599 const RetainSummary *StopSummary; 600 601 //==-----------------------------------------------------------------==// 602 // Methods. 603 //==-----------------------------------------------------------------==// 604 605 /// getArgEffects - Returns a persistent ArgEffects object based on the 606 /// data in ScratchArgs. 607 ArgEffects getArgEffects(); 608 609 enum UnaryFuncKind { cfretain, cfrelease, cfmakecollectable }; 610 611public: 612 RetEffect getObjAllocRetEffect() const { return ObjCAllocRetE; } 613 614 const RetainSummary *getDefaultSummary() { 615 return &DefaultSummary; 616 } 617 618 const RetainSummary *getUnarySummary(const FunctionType* FT, 619 UnaryFuncKind func); 620 621 const RetainSummary *getCFSummaryCreateRule(const FunctionDecl *FD); 622 const RetainSummary *getCFSummaryGetRule(const FunctionDecl *FD); 623 const RetainSummary *getCFCreateGetRuleSummary(const FunctionDecl *FD); 624 625 const RetainSummary *getPersistentSummary(ArgEffects AE, RetEffect RetEff, 626 ArgEffect ReceiverEff = DoNothing, 627 ArgEffect DefaultEff = MayEscape); 628 629 const RetainSummary *getPersistentSummary(RetEffect RE, 630 ArgEffect ReceiverEff = DoNothing, 631 ArgEffect DefaultEff = MayEscape) { 632 return getPersistentSummary(getArgEffects(), RE, ReceiverEff, DefaultEff); 633 } 634 635 const RetainSummary *getPersistentStopSummary() { 636 if (StopSummary) 637 return StopSummary; 638 639 StopSummary = getPersistentSummary(RetEffect::MakeNoRet(), 640 StopTracking, StopTracking); 641 642 return StopSummary; 643 } 644 645 const RetainSummary *getInitMethodSummary(QualType RetTy); 646 647 void InitializeClassMethodSummaries(); 648 void InitializeMethodSummaries(); 649private: 650 void addNSObjectClsMethSummary(Selector S, const RetainSummary *Summ) { 651 ObjCClassMethodSummaries[S] = Summ; 652 } 653 654 void addNSObjectMethSummary(Selector S, const RetainSummary *Summ) { 655 ObjCMethodSummaries[S] = Summ; 656 } 657 658 void addClassMethSummary(const char* Cls, const char* nullaryName, 659 const RetainSummary *Summ) { 660 IdentifierInfo* ClsII = &Ctx.Idents.get(Cls); 661 Selector S = GetNullarySelector(nullaryName, Ctx); 662 ObjCClassMethodSummaries[ObjCSummaryKey(ClsII, S)] = Summ; 663 } 664 665 void addInstMethSummary(const char* Cls, const char* nullaryName, 666 const RetainSummary *Summ) { 667 IdentifierInfo* ClsII = &Ctx.Idents.get(Cls); 668 Selector S = GetNullarySelector(nullaryName, Ctx); 669 ObjCMethodSummaries[ObjCSummaryKey(ClsII, S)] = Summ; 670 } 671 672 Selector generateSelector(va_list argp) { 673 SmallVector<IdentifierInfo*, 10> II; 674 675 while (const char* s = va_arg(argp, const char*)) 676 II.push_back(&Ctx.Idents.get(s)); 677 678 return Ctx.Selectors.getSelector(II.size(), &II[0]); 679 } 680 681 void addMethodSummary(IdentifierInfo *ClsII, ObjCMethodSummariesTy& Summaries, 682 const RetainSummary * Summ, va_list argp) { 683 Selector S = generateSelector(argp); 684 Summaries[ObjCSummaryKey(ClsII, S)] = Summ; 685 } 686 687 void addInstMethSummary(const char* Cls, const RetainSummary * Summ, ...) { 688 va_list argp; 689 va_start(argp, Summ); 690 addMethodSummary(&Ctx.Idents.get(Cls), ObjCMethodSummaries, Summ, argp); 691 va_end(argp); 692 } 693 694 void addClsMethSummary(const char* Cls, const RetainSummary * Summ, ...) { 695 va_list argp; 696 va_start(argp, Summ); 697 addMethodSummary(&Ctx.Idents.get(Cls),ObjCClassMethodSummaries, Summ, argp); 698 va_end(argp); 699 } 700 701 void addClsMethSummary(IdentifierInfo *II, const RetainSummary * Summ, ...) { 702 va_list argp; 703 va_start(argp, Summ); 704 addMethodSummary(II, ObjCClassMethodSummaries, Summ, argp); 705 va_end(argp); 706 } 707 708public: 709 710 RetainSummaryManager(ASTContext &ctx, bool gcenabled, bool usesARC) 711 : Ctx(ctx), 712 GCEnabled(gcenabled), 713 ARCEnabled(usesARC), 714 AF(BPAlloc), ScratchArgs(AF.getEmptyMap()), 715 ObjCAllocRetE(gcenabled 716 ? RetEffect::MakeGCNotOwned() 717 : (usesARC ? RetEffect::MakeARCNotOwned() 718 : RetEffect::MakeOwned(RetEffect::ObjC, true))), 719 ObjCInitRetE(gcenabled 720 ? RetEffect::MakeGCNotOwned() 721 : (usesARC ? RetEffect::MakeARCNotOwned() 722 : RetEffect::MakeOwnedWhenTrackedReceiver())), 723 DefaultSummary(AF.getEmptyMap() /* per-argument effects (none) */, 724 RetEffect::MakeNoRet() /* return effect */, 725 MayEscape, /* default argument effect */ 726 DoNothing /* receiver effect */), 727 StopSummary(0) { 728 729 InitializeClassMethodSummaries(); 730 InitializeMethodSummaries(); 731 } 732 733 const RetainSummary *getSummary(const FunctionDecl *FD); 734 735 const RetainSummary *getInstanceMethodSummary(const ObjCMessage &msg, 736 ProgramStateRef state, 737 const LocationContext *LC); 738 739 const RetainSummary *getInstanceMethodSummary(const ObjCMessage &msg, 740 const ObjCInterfaceDecl *ID) { 741 return getInstanceMethodSummary(msg.getSelector(), 0, 742 ID, msg.getMethodDecl(), msg.getType(Ctx)); 743 } 744 745 const RetainSummary *getInstanceMethodSummary(Selector S, 746 IdentifierInfo *ClsName, 747 const ObjCInterfaceDecl *ID, 748 const ObjCMethodDecl *MD, 749 QualType RetTy); 750 751 const RetainSummary *getClassMethodSummary(Selector S, 752 IdentifierInfo *ClsName, 753 const ObjCInterfaceDecl *ID, 754 const ObjCMethodDecl *MD, 755 QualType RetTy); 756 757 const RetainSummary *getClassMethodSummary(const ObjCMessage &msg) { 758 const ObjCInterfaceDecl *Class = 0; 759 if (!msg.isInstanceMessage()) 760 Class = msg.getReceiverInterface(); 761 762 return getClassMethodSummary(msg.getSelector(), 763 Class? Class->getIdentifier() : 0, 764 Class, 765 msg.getMethodDecl(), msg.getType(Ctx)); 766 } 767 768 /// getMethodSummary - This version of getMethodSummary is used to query 769 /// the summary for the current method being analyzed. 770 const RetainSummary *getMethodSummary(const ObjCMethodDecl *MD) { 771 // FIXME: Eventually this should be unneeded. 772 const ObjCInterfaceDecl *ID = MD->getClassInterface(); 773 Selector S = MD->getSelector(); 774 IdentifierInfo *ClsName = ID->getIdentifier(); 775 QualType ResultTy = MD->getResultType(); 776 777 if (MD->isInstanceMethod()) 778 return getInstanceMethodSummary(S, ClsName, ID, MD, ResultTy); 779 else 780 return getClassMethodSummary(S, ClsName, ID, MD, ResultTy); 781 } 782 783 const RetainSummary *getCommonMethodSummary(const ObjCMethodDecl *MD, 784 Selector S, QualType RetTy); 785 786 void updateSummaryFromAnnotations(const RetainSummary *&Summ, 787 const ObjCMethodDecl *MD); 788 789 void updateSummaryFromAnnotations(const RetainSummary *&Summ, 790 const FunctionDecl *FD); 791 792 bool isGCEnabled() const { return GCEnabled; } 793 794 bool isARCEnabled() const { return ARCEnabled; } 795 796 bool isARCorGCEnabled() const { return GCEnabled || ARCEnabled; } 797 798 const RetainSummary *copySummary(const RetainSummary *OldSumm) { 799 RetainSummary *Summ = (RetainSummary *) BPAlloc.Allocate<RetainSummary>(); 800 new (Summ) RetainSummary(*OldSumm); 801 return Summ; 802 } 803}; 804 805// Used to avoid allocating long-term (BPAlloc'd) memory for default retain 806// summaries. If a function or method looks like it has a default summary, but 807// it has annotations, the annotations are added to the stack-based template 808// and then copied into managed memory. 809class RetainSummaryTemplate { 810 RetainSummaryManager &Manager; 811 const RetainSummary *&RealSummary; 812 const RetainSummary *BaseSummary; 813 RetainSummary ScratchSummary; 814 bool Accessed; 815public: 816 RetainSummaryTemplate(const RetainSummary *&real, const RetainSummary &base, 817 RetainSummaryManager &manager) 818 : Manager(manager), 819 RealSummary(real), 820 BaseSummary(&base), 821 ScratchSummary(base), 822 Accessed(false) {} 823 824 ~RetainSummaryTemplate() { 825 if (Accessed) 826 RealSummary = Manager.copySummary(&ScratchSummary); 827 else if (!RealSummary) 828 RealSummary = BaseSummary; 829 } 830 831 RetainSummary &operator*() { 832 Accessed = true; 833 return ScratchSummary; 834 } 835 836 RetainSummary *operator->() { 837 Accessed = true; 838 return &ScratchSummary; 839 } 840}; 841 842} // end anonymous namespace 843 844//===----------------------------------------------------------------------===// 845// Implementation of checker data structures. 846//===----------------------------------------------------------------------===// 847 848ArgEffects RetainSummaryManager::getArgEffects() { 849 ArgEffects AE = ScratchArgs; 850 ScratchArgs = AF.getEmptyMap(); 851 return AE; 852} 853 854const RetainSummary * 855RetainSummaryManager::getPersistentSummary(ArgEffects AE, RetEffect RetEff, 856 ArgEffect ReceiverEff, 857 ArgEffect DefaultEff) { 858 // Create the summary and return it. 859 RetainSummary *Summ = (RetainSummary *) BPAlloc.Allocate<RetainSummary>(); 860 new (Summ) RetainSummary(AE, RetEff, DefaultEff, ReceiverEff); 861 return Summ; 862} 863 864//===----------------------------------------------------------------------===// 865// Summary creation for functions (largely uses of Core Foundation). 866//===----------------------------------------------------------------------===// 867 868static bool isRetain(const FunctionDecl *FD, StringRef FName) { 869 return FName.endswith("Retain"); 870} 871 872static bool isRelease(const FunctionDecl *FD, StringRef FName) { 873 return FName.endswith("Release"); 874} 875 876static bool isMakeCollectable(const FunctionDecl *FD, StringRef FName) { 877 // FIXME: Remove FunctionDecl parameter. 878 // FIXME: Is it really okay if MakeCollectable isn't a suffix? 879 return FName.find("MakeCollectable") != StringRef::npos; 880} 881 882const RetainSummary * RetainSummaryManager::getSummary(const FunctionDecl *FD) { 883 // Look up a summary in our cache of FunctionDecls -> Summaries. 884 FuncSummariesTy::iterator I = FuncSummaries.find(FD); 885 if (I != FuncSummaries.end()) 886 return I->second; 887 888 // No summary? Generate one. 889 const RetainSummary *S = 0; 890 891 do { 892 // We generate "stop" summaries for implicitly defined functions. 893 if (FD->isImplicit()) { 894 S = getPersistentStopSummary(); 895 break; 896 } 897 // For C++ methods, generate an implicit "stop" summary as well. We 898 // can relax this once we have a clear policy for C++ methods and 899 // ownership attributes. 900 if (isa<CXXMethodDecl>(FD)) { 901 S = getPersistentStopSummary(); 902 break; 903 } 904 905 // [PR 3337] Use 'getAs<FunctionType>' to strip away any typedefs on the 906 // function's type. 907 const FunctionType* FT = FD->getType()->getAs<FunctionType>(); 908 const IdentifierInfo *II = FD->getIdentifier(); 909 if (!II) 910 break; 911 912 StringRef FName = II->getName(); 913 914 // Strip away preceding '_'. Doing this here will effect all the checks 915 // down below. 916 FName = FName.substr(FName.find_first_not_of('_')); 917 918 // Inspect the result type. 919 QualType RetTy = FT->getResultType(); 920 921 // FIXME: This should all be refactored into a chain of "summary lookup" 922 // filters. 923 assert(ScratchArgs.isEmpty()); 924 925 if (FName == "pthread_create") { 926 // Part of: <rdar://problem/7299394>. This will be addressed 927 // better with IPA. 928 S = getPersistentStopSummary(); 929 } else if (FName == "NSMakeCollectable") { 930 // Handle: id NSMakeCollectable(CFTypeRef) 931 S = (RetTy->isObjCIdType()) 932 ? getUnarySummary(FT, cfmakecollectable) 933 : getPersistentStopSummary(); 934 } else if (FName == "IOBSDNameMatching" || 935 FName == "IOServiceMatching" || 936 FName == "IOServiceNameMatching" || 937 FName == "IORegistryEntryIDMatching" || 938 FName == "IOOpenFirmwarePathMatching") { 939 // Part of <rdar://problem/6961230>. (IOKit) 940 // This should be addressed using a API table. 941 S = getPersistentSummary(RetEffect::MakeOwned(RetEffect::CF, true), 942 DoNothing, DoNothing); 943 } else if (FName == "IOServiceGetMatchingService" || 944 FName == "IOServiceGetMatchingServices") { 945 // FIXES: <rdar://problem/6326900> 946 // This should be addressed using a API table. This strcmp is also 947 // a little gross, but there is no need to super optimize here. 948 ScratchArgs = AF.add(ScratchArgs, 1, DecRef); 949 S = getPersistentSummary(RetEffect::MakeNoRet(), DoNothing, DoNothing); 950 } else if (FName == "IOServiceAddNotification" || 951 FName == "IOServiceAddMatchingNotification") { 952 // Part of <rdar://problem/6961230>. (IOKit) 953 // This should be addressed using a API table. 954 ScratchArgs = AF.add(ScratchArgs, 2, DecRef); 955 S = getPersistentSummary(RetEffect::MakeNoRet(), DoNothing, DoNothing); 956 } else if (FName == "CVPixelBufferCreateWithBytes") { 957 // FIXES: <rdar://problem/7283567> 958 // Eventually this can be improved by recognizing that the pixel 959 // buffer passed to CVPixelBufferCreateWithBytes is released via 960 // a callback and doing full IPA to make sure this is done correctly. 961 // FIXME: This function has an out parameter that returns an 962 // allocated object. 963 ScratchArgs = AF.add(ScratchArgs, 7, StopTracking); 964 S = getPersistentSummary(RetEffect::MakeNoRet(), DoNothing, DoNothing); 965 } else if (FName == "CGBitmapContextCreateWithData") { 966 // FIXES: <rdar://problem/7358899> 967 // Eventually this can be improved by recognizing that 'releaseInfo' 968 // passed to CGBitmapContextCreateWithData is released via 969 // a callback and doing full IPA to make sure this is done correctly. 970 ScratchArgs = AF.add(ScratchArgs, 8, StopTracking); 971 S = getPersistentSummary(RetEffect::MakeOwned(RetEffect::CF, true), 972 DoNothing, DoNothing); 973 } else if (FName == "CVPixelBufferCreateWithPlanarBytes") { 974 // FIXES: <rdar://problem/7283567> 975 // Eventually this can be improved by recognizing that the pixel 976 // buffer passed to CVPixelBufferCreateWithPlanarBytes is released 977 // via a callback and doing full IPA to make sure this is done 978 // correctly. 979 ScratchArgs = AF.add(ScratchArgs, 12, StopTracking); 980 S = getPersistentSummary(RetEffect::MakeNoRet(), DoNothing, DoNothing); 981 } 982 983 // Did we get a summary? 984 if (S) 985 break; 986 987 // Enable this code once the semantics of NSDeallocateObject are resolved 988 // for GC. <rdar://problem/6619988> 989#if 0 990 // Handle: NSDeallocateObject(id anObject); 991 // This method does allow 'nil' (although we don't check it now). 992 if (strcmp(FName, "NSDeallocateObject") == 0) { 993 return RetTy == Ctx.VoidTy 994 ? getPersistentSummary(RetEffect::MakeNoRet(), DoNothing, Dealloc) 995 : getPersistentStopSummary(); 996 } 997#endif 998 999 if (RetTy->isPointerType()) { 1000 // For CoreFoundation ('CF') types. 1001 if (cocoa::isRefType(RetTy, "CF", FName)) { 1002 if (isRetain(FD, FName)) 1003 S = getUnarySummary(FT, cfretain); 1004 else if (isMakeCollectable(FD, FName)) 1005 S = getUnarySummary(FT, cfmakecollectable); 1006 else 1007 S = getCFCreateGetRuleSummary(FD); 1008 1009 break; 1010 } 1011 1012 // For CoreGraphics ('CG') types. 1013 if (cocoa::isRefType(RetTy, "CG", FName)) { 1014 if (isRetain(FD, FName)) 1015 S = getUnarySummary(FT, cfretain); 1016 else 1017 S = getCFCreateGetRuleSummary(FD); 1018 1019 break; 1020 } 1021 1022 // For the Disk Arbitration API (DiskArbitration/DADisk.h) 1023 if (cocoa::isRefType(RetTy, "DADisk") || 1024 cocoa::isRefType(RetTy, "DADissenter") || 1025 cocoa::isRefType(RetTy, "DASessionRef")) { 1026 S = getCFCreateGetRuleSummary(FD); 1027 break; 1028 } 1029 1030 break; 1031 } 1032 1033 // Check for release functions, the only kind of functions that we care 1034 // about that don't return a pointer type. 1035 if (FName[0] == 'C' && (FName[1] == 'F' || FName[1] == 'G')) { 1036 // Test for 'CGCF'. 1037 FName = FName.substr(FName.startswith("CGCF") ? 4 : 2); 1038 1039 if (isRelease(FD, FName)) 1040 S = getUnarySummary(FT, cfrelease); 1041 else { 1042 assert (ScratchArgs.isEmpty()); 1043 // Remaining CoreFoundation and CoreGraphics functions. 1044 // We use to assume that they all strictly followed the ownership idiom 1045 // and that ownership cannot be transferred. While this is technically 1046 // correct, many methods allow a tracked object to escape. For example: 1047 // 1048 // CFMutableDictionaryRef x = CFDictionaryCreateMutable(...); 1049 // CFDictionaryAddValue(y, key, x); 1050 // CFRelease(x); 1051 // ... it is okay to use 'x' since 'y' has a reference to it 1052 // 1053 // We handle this and similar cases with the follow heuristic. If the 1054 // function name contains "InsertValue", "SetValue", "AddValue", 1055 // "AppendValue", or "SetAttribute", then we assume that arguments may 1056 // "escape." This means that something else holds on to the object, 1057 // allowing it be used even after its local retain count drops to 0. 1058 ArgEffect E = (StrInStrNoCase(FName, "InsertValue") != StringRef::npos|| 1059 StrInStrNoCase(FName, "AddValue") != StringRef::npos || 1060 StrInStrNoCase(FName, "SetValue") != StringRef::npos || 1061 StrInStrNoCase(FName, "AppendValue") != StringRef::npos|| 1062 StrInStrNoCase(FName, "SetAttribute") != StringRef::npos) 1063 ? MayEscape : DoNothing; 1064 1065 S = getPersistentSummary(RetEffect::MakeNoRet(), DoNothing, E); 1066 } 1067 } 1068 } 1069 while (0); 1070 1071 // Annotations override defaults. 1072 updateSummaryFromAnnotations(S, FD); 1073 1074 FuncSummaries[FD] = S; 1075 return S; 1076} 1077 1078const RetainSummary * 1079RetainSummaryManager::getCFCreateGetRuleSummary(const FunctionDecl *FD) { 1080 if (coreFoundation::followsCreateRule(FD)) 1081 return getCFSummaryCreateRule(FD); 1082 1083 return getCFSummaryGetRule(FD); 1084} 1085 1086const RetainSummary * 1087RetainSummaryManager::getUnarySummary(const FunctionType* FT, 1088 UnaryFuncKind func) { 1089 1090 // Sanity check that this is *really* a unary function. This can 1091 // happen if people do weird things. 1092 const FunctionProtoType* FTP = dyn_cast<FunctionProtoType>(FT); 1093 if (!FTP || FTP->getNumArgs() != 1) 1094 return getPersistentStopSummary(); 1095 1096 assert (ScratchArgs.isEmpty()); 1097 1098 ArgEffect Effect; 1099 switch (func) { 1100 case cfretain: Effect = IncRef; break; 1101 case cfrelease: Effect = DecRef; break; 1102 case cfmakecollectable: Effect = MakeCollectable; break; 1103 } 1104 1105 ScratchArgs = AF.add(ScratchArgs, 0, Effect); 1106 return getPersistentSummary(RetEffect::MakeNoRet(), DoNothing, DoNothing); 1107} 1108 1109const RetainSummary * 1110RetainSummaryManager::getCFSummaryCreateRule(const FunctionDecl *FD) { 1111 assert (ScratchArgs.isEmpty()); 1112 1113 return getPersistentSummary(RetEffect::MakeOwned(RetEffect::CF, true)); 1114} 1115 1116const RetainSummary * 1117RetainSummaryManager::getCFSummaryGetRule(const FunctionDecl *FD) { 1118 assert (ScratchArgs.isEmpty()); 1119 return getPersistentSummary(RetEffect::MakeNotOwned(RetEffect::CF), 1120 DoNothing, DoNothing); 1121} 1122 1123//===----------------------------------------------------------------------===// 1124// Summary creation for Selectors. 1125//===----------------------------------------------------------------------===// 1126 1127const RetainSummary * 1128RetainSummaryManager::getInitMethodSummary(QualType RetTy) { 1129 assert(ScratchArgs.isEmpty()); 1130 // 'init' methods conceptually return a newly allocated object and claim 1131 // the receiver. 1132 if (cocoa::isCocoaObjectRef(RetTy) || 1133 coreFoundation::isCFObjectRef(RetTy)) 1134 return getPersistentSummary(ObjCInitRetE, DecRefMsg); 1135 1136 return getDefaultSummary(); 1137} 1138 1139void 1140RetainSummaryManager::updateSummaryFromAnnotations(const RetainSummary *&Summ, 1141 const FunctionDecl *FD) { 1142 if (!FD) 1143 return; 1144 1145 RetainSummaryTemplate Template(Summ, DefaultSummary, *this); 1146 1147 // Effects on the parameters. 1148 unsigned parm_idx = 0; 1149 for (FunctionDecl::param_const_iterator pi = FD->param_begin(), 1150 pe = FD->param_end(); pi != pe; ++pi, ++parm_idx) { 1151 const ParmVarDecl *pd = *pi; 1152 if (pd->getAttr<NSConsumedAttr>()) { 1153 if (!GCEnabled) { 1154 Template->addArg(AF, parm_idx, DecRef); 1155 } 1156 } else if (pd->getAttr<CFConsumedAttr>()) { 1157 Template->addArg(AF, parm_idx, DecRef); 1158 } 1159 } 1160 1161 QualType RetTy = FD->getResultType(); 1162 1163 // Determine if there is a special return effect for this method. 1164 if (cocoa::isCocoaObjectRef(RetTy)) { 1165 if (FD->getAttr<NSReturnsRetainedAttr>()) { 1166 Template->setRetEffect(ObjCAllocRetE); 1167 } 1168 else if (FD->getAttr<CFReturnsRetainedAttr>()) { 1169 Template->setRetEffect(RetEffect::MakeOwned(RetEffect::CF, true)); 1170 } 1171 else if (FD->getAttr<NSReturnsNotRetainedAttr>()) { 1172 Template->setRetEffect(RetEffect::MakeNotOwned(RetEffect::ObjC)); 1173 } 1174 else if (FD->getAttr<CFReturnsNotRetainedAttr>()) { 1175 Template->setRetEffect(RetEffect::MakeNotOwned(RetEffect::CF)); 1176 } 1177 } else if (RetTy->getAs<PointerType>()) { 1178 if (FD->getAttr<CFReturnsRetainedAttr>()) { 1179 Template->setRetEffect(RetEffect::MakeOwned(RetEffect::CF, true)); 1180 } 1181 else if (FD->getAttr<CFReturnsNotRetainedAttr>()) { 1182 Template->setRetEffect(RetEffect::MakeNotOwned(RetEffect::CF)); 1183 } 1184 } 1185} 1186 1187void 1188RetainSummaryManager::updateSummaryFromAnnotations(const RetainSummary *&Summ, 1189 const ObjCMethodDecl *MD) { 1190 if (!MD) 1191 return; 1192 1193 RetainSummaryTemplate Template(Summ, DefaultSummary, *this); 1194 1195 bool isTrackedLoc = false; 1196 1197 // Effects on the receiver. 1198 if (MD->getAttr<NSConsumesSelfAttr>()) { 1199 if (!GCEnabled) 1200 Template->setReceiverEffect(DecRefMsg); 1201 } 1202 1203 // Effects on the parameters. 1204 unsigned parm_idx = 0; 1205 for (ObjCMethodDecl::param_const_iterator 1206 pi=MD->param_begin(), pe=MD->param_end(); 1207 pi != pe; ++pi, ++parm_idx) { 1208 const ParmVarDecl *pd = *pi; 1209 if (pd->getAttr<NSConsumedAttr>()) { 1210 if (!GCEnabled) 1211 Template->addArg(AF, parm_idx, DecRef); 1212 } 1213 else if(pd->getAttr<CFConsumedAttr>()) { 1214 Template->addArg(AF, parm_idx, DecRef); 1215 } 1216 } 1217 1218 // Determine if there is a special return effect for this method. 1219 if (cocoa::isCocoaObjectRef(MD->getResultType())) { 1220 if (MD->getAttr<NSReturnsRetainedAttr>()) { 1221 Template->setRetEffect(ObjCAllocRetE); 1222 return; 1223 } 1224 if (MD->getAttr<NSReturnsNotRetainedAttr>()) { 1225 Template->setRetEffect(RetEffect::MakeNotOwned(RetEffect::ObjC)); 1226 return; 1227 } 1228 1229 isTrackedLoc = true; 1230 } else { 1231 isTrackedLoc = MD->getResultType()->getAs<PointerType>() != NULL; 1232 } 1233 1234 if (isTrackedLoc) { 1235 if (MD->getAttr<CFReturnsRetainedAttr>()) 1236 Template->setRetEffect(RetEffect::MakeOwned(RetEffect::CF, true)); 1237 else if (MD->getAttr<CFReturnsNotRetainedAttr>()) 1238 Template->setRetEffect(RetEffect::MakeNotOwned(RetEffect::CF)); 1239 } 1240} 1241 1242const RetainSummary * 1243RetainSummaryManager::getCommonMethodSummary(const ObjCMethodDecl *MD, 1244 Selector S, QualType RetTy) { 1245 1246 if (MD) { 1247 // Scan the method decl for 'void*' arguments. These should be treated 1248 // as 'StopTracking' because they are often used with delegates. 1249 // Delegates are a frequent form of false positives with the retain 1250 // count checker. 1251 unsigned i = 0; 1252 for (ObjCMethodDecl::param_const_iterator I = MD->param_begin(), 1253 E = MD->param_end(); I != E; ++I, ++i) 1254 if (const ParmVarDecl *PD = *I) { 1255 QualType Ty = Ctx.getCanonicalType(PD->getType()); 1256 if (Ty.getLocalUnqualifiedType() == Ctx.VoidPtrTy) 1257 ScratchArgs = AF.add(ScratchArgs, i, StopTracking); 1258 } 1259 } 1260 1261 // Any special effect for the receiver? 1262 ArgEffect ReceiverEff = DoNothing; 1263 1264 // If one of the arguments in the selector has the keyword 'delegate' we 1265 // should stop tracking the reference count for the receiver. This is 1266 // because the reference count is quite possibly handled by a delegate 1267 // method. 1268 if (S.isKeywordSelector()) { 1269 const std::string &str = S.getAsString(); 1270 assert(!str.empty()); 1271 if (StrInStrNoCase(str, "delegate:") != StringRef::npos) 1272 ReceiverEff = StopTracking; 1273 } 1274 1275 // Look for methods that return an owned object. 1276 if (cocoa::isCocoaObjectRef(RetTy)) { 1277 // EXPERIMENTAL: assume the Cocoa conventions for all objects returned 1278 // by instance methods. 1279 RetEffect E = cocoa::followsFundamentalRule(S, MD) 1280 ? ObjCAllocRetE : RetEffect::MakeNotOwned(RetEffect::ObjC); 1281 1282 return getPersistentSummary(E, ReceiverEff, MayEscape); 1283 } 1284 1285 // Look for methods that return an owned core foundation object. 1286 if (coreFoundation::isCFObjectRef(RetTy)) { 1287 RetEffect E = cocoa::followsFundamentalRule(S, MD) 1288 ? RetEffect::MakeOwned(RetEffect::CF, true) 1289 : RetEffect::MakeNotOwned(RetEffect::CF); 1290 1291 return getPersistentSummary(E, ReceiverEff, MayEscape); 1292 } 1293 1294 if (ScratchArgs.isEmpty() && ReceiverEff == DoNothing) 1295 return getDefaultSummary(); 1296 1297 return getPersistentSummary(RetEffect::MakeNoRet(), ReceiverEff, MayEscape); 1298} 1299 1300const RetainSummary * 1301RetainSummaryManager::getInstanceMethodSummary(const ObjCMessage &msg, 1302 ProgramStateRef state, 1303 const LocationContext *LC) { 1304 1305 // We need the type-information of the tracked receiver object 1306 // Retrieve it from the state. 1307 const Expr *Receiver = msg.getInstanceReceiver(); 1308 const ObjCInterfaceDecl *ID = 0; 1309 1310 // FIXME: Is this really working as expected? There are cases where 1311 // we just use the 'ID' from the message expression. 1312 SVal receiverV; 1313 1314 if (Receiver) { 1315 receiverV = state->getSValAsScalarOrLoc(Receiver, LC); 1316 1317 // FIXME: Eventually replace the use of state->get<RefBindings> with 1318 // a generic API for reasoning about the Objective-C types of symbolic 1319 // objects. 1320 if (SymbolRef Sym = receiverV.getAsLocSymbol()) 1321 if (const RefVal *T = state->get<RefBindings>(Sym)) 1322 if (const ObjCObjectPointerType* PT = 1323 T->getType()->getAs<ObjCObjectPointerType>()) 1324 ID = PT->getInterfaceDecl(); 1325 1326 // FIXME: this is a hack. This may or may not be the actual method 1327 // that is called. 1328 if (!ID) { 1329 if (const ObjCObjectPointerType *PT = 1330 Receiver->getType()->getAs<ObjCObjectPointerType>()) 1331 ID = PT->getInterfaceDecl(); 1332 } 1333 } else { 1334 // FIXME: Hack for 'super'. 1335 ID = msg.getReceiverInterface(); 1336 } 1337 1338 // FIXME: The receiver could be a reference to a class, meaning that 1339 // we should use the class method. 1340 return getInstanceMethodSummary(msg, ID); 1341} 1342 1343const RetainSummary * 1344RetainSummaryManager::getInstanceMethodSummary(Selector S, 1345 IdentifierInfo *ClsName, 1346 const ObjCInterfaceDecl *ID, 1347 const ObjCMethodDecl *MD, 1348 QualType RetTy) { 1349 1350 // Look up a summary in our summary cache. 1351 const RetainSummary *Summ = ObjCMethodSummaries.find(ID, ClsName, S); 1352 1353 if (!Summ) { 1354 assert(ScratchArgs.isEmpty()); 1355 1356 // "initXXX": pass-through for receiver. 1357 if (cocoa::deriveNamingConvention(S, MD) == cocoa::InitRule) 1358 Summ = getInitMethodSummary(RetTy); 1359 else 1360 Summ = getCommonMethodSummary(MD, S, RetTy); 1361 1362 // Annotations override defaults. 1363 updateSummaryFromAnnotations(Summ, MD); 1364 1365 // Memoize the summary. 1366 ObjCMethodSummaries[ObjCSummaryKey(ID, ClsName, S)] = Summ; 1367 } 1368 1369 return Summ; 1370} 1371 1372const RetainSummary * 1373RetainSummaryManager::getClassMethodSummary(Selector S, IdentifierInfo *ClsName, 1374 const ObjCInterfaceDecl *ID, 1375 const ObjCMethodDecl *MD, 1376 QualType RetTy) { 1377 1378 assert(ClsName && "Class name must be specified."); 1379 const RetainSummary *Summ = ObjCClassMethodSummaries.find(ID, ClsName, S); 1380 1381 if (!Summ) { 1382 Summ = getCommonMethodSummary(MD, S, RetTy); 1383 1384 // Annotations override defaults. 1385 updateSummaryFromAnnotations(Summ, MD); 1386 1387 // Memoize the summary. 1388 ObjCClassMethodSummaries[ObjCSummaryKey(ID, ClsName, S)] = Summ; 1389 } 1390 1391 return Summ; 1392} 1393 1394void RetainSummaryManager::InitializeClassMethodSummaries() { 1395 assert(ScratchArgs.isEmpty()); 1396 // Create the [NSAssertionHandler currentHander] summary. 1397 addClassMethSummary("NSAssertionHandler", "currentHandler", 1398 getPersistentSummary(RetEffect::MakeNotOwned(RetEffect::ObjC))); 1399 1400 // Create the [NSAutoreleasePool addObject:] summary. 1401 ScratchArgs = AF.add(ScratchArgs, 0, Autorelease); 1402 addClassMethSummary("NSAutoreleasePool", "addObject", 1403 getPersistentSummary(RetEffect::MakeNoRet(), 1404 DoNothing, Autorelease)); 1405 1406 // Create the summaries for [NSObject performSelector...]. We treat 1407 // these as 'stop tracking' for the arguments because they are often 1408 // used for delegates that can release the object. When we have better 1409 // inter-procedural analysis we can potentially do something better. This 1410 // workaround is to remove false positives. 1411 const RetainSummary *Summ = 1412 getPersistentSummary(RetEffect::MakeNoRet(), DoNothing, StopTracking); 1413 IdentifierInfo *NSObjectII = &Ctx.Idents.get("NSObject"); 1414 addClsMethSummary(NSObjectII, Summ, "performSelector", "withObject", 1415 "afterDelay", NULL); 1416 addClsMethSummary(NSObjectII, Summ, "performSelector", "withObject", 1417 "afterDelay", "inModes", NULL); 1418 addClsMethSummary(NSObjectII, Summ, "performSelectorOnMainThread", 1419 "withObject", "waitUntilDone", NULL); 1420 addClsMethSummary(NSObjectII, Summ, "performSelectorOnMainThread", 1421 "withObject", "waitUntilDone", "modes", NULL); 1422 addClsMethSummary(NSObjectII, Summ, "performSelector", "onThread", 1423 "withObject", "waitUntilDone", NULL); 1424 addClsMethSummary(NSObjectII, Summ, "performSelector", "onThread", 1425 "withObject", "waitUntilDone", "modes", NULL); 1426 addClsMethSummary(NSObjectII, Summ, "performSelectorInBackground", 1427 "withObject", NULL); 1428} 1429 1430void RetainSummaryManager::InitializeMethodSummaries() { 1431 1432 assert (ScratchArgs.isEmpty()); 1433 1434 // Create the "init" selector. It just acts as a pass-through for the 1435 // receiver. 1436 const RetainSummary *InitSumm = getPersistentSummary(ObjCInitRetE, DecRefMsg); 1437 addNSObjectMethSummary(GetNullarySelector("init", Ctx), InitSumm); 1438 1439 // awakeAfterUsingCoder: behaves basically like an 'init' method. It 1440 // claims the receiver and returns a retained object. 1441 addNSObjectMethSummary(GetUnarySelector("awakeAfterUsingCoder", Ctx), 1442 InitSumm); 1443 1444 // The next methods are allocators. 1445 const RetainSummary *AllocSumm = getPersistentSummary(ObjCAllocRetE); 1446 const RetainSummary *CFAllocSumm = 1447 getPersistentSummary(RetEffect::MakeOwned(RetEffect::CF, true)); 1448 1449 // Create the "retain" selector. 1450 RetEffect NoRet = RetEffect::MakeNoRet(); 1451 const RetainSummary *Summ = getPersistentSummary(NoRet, IncRefMsg); 1452 addNSObjectMethSummary(GetNullarySelector("retain", Ctx), Summ); 1453 1454 // Create the "release" selector. 1455 Summ = getPersistentSummary(NoRet, DecRefMsg); 1456 addNSObjectMethSummary(GetNullarySelector("release", Ctx), Summ); 1457 1458 // Create the "drain" selector. 1459 Summ = getPersistentSummary(NoRet, isGCEnabled() ? DoNothing : DecRef); 1460 addNSObjectMethSummary(GetNullarySelector("drain", Ctx), Summ); 1461 1462 // Create the -dealloc summary. 1463 Summ = getPersistentSummary(NoRet, Dealloc); 1464 addNSObjectMethSummary(GetNullarySelector("dealloc", Ctx), Summ); 1465 1466 // Create the "autorelease" selector. 1467 Summ = getPersistentSummary(NoRet, Autorelease); 1468 addNSObjectMethSummary(GetNullarySelector("autorelease", Ctx), Summ); 1469 1470 // Specially handle NSAutoreleasePool. 1471 addInstMethSummary("NSAutoreleasePool", "init", 1472 getPersistentSummary(NoRet, NewAutoreleasePool)); 1473 1474 // For NSWindow, allocated objects are (initially) self-owned. 1475 // FIXME: For now we opt for false negatives with NSWindow, as these objects 1476 // self-own themselves. However, they only do this once they are displayed. 1477 // Thus, we need to track an NSWindow's display status. 1478 // This is tracked in <rdar://problem/6062711>. 1479 // See also http://llvm.org/bugs/show_bug.cgi?id=3714. 1480 const RetainSummary *NoTrackYet = getPersistentSummary(RetEffect::MakeNoRet(), 1481 StopTracking, 1482 StopTracking); 1483 1484 addClassMethSummary("NSWindow", "alloc", NoTrackYet); 1485 1486#if 0 1487 addInstMethSummary("NSWindow", NoTrackYet, "initWithContentRect", 1488 "styleMask", "backing", "defer", NULL); 1489 1490 addInstMethSummary("NSWindow", NoTrackYet, "initWithContentRect", 1491 "styleMask", "backing", "defer", "screen", NULL); 1492#endif 1493 1494 // For NSPanel (which subclasses NSWindow), allocated objects are not 1495 // self-owned. 1496 // FIXME: For now we don't track NSPanels. object for the same reason 1497 // as for NSWindow objects. 1498 addClassMethSummary("NSPanel", "alloc", NoTrackYet); 1499 1500#if 0 1501 addInstMethSummary("NSPanel", NoTrackYet, "initWithContentRect", 1502 "styleMask", "backing", "defer", NULL); 1503 1504 addInstMethSummary("NSPanel", NoTrackYet, "initWithContentRect", 1505 "styleMask", "backing", "defer", "screen", NULL); 1506#endif 1507 1508 // Don't track allocated autorelease pools yet, as it is okay to prematurely 1509 // exit a method. 1510 addClassMethSummary("NSAutoreleasePool", "alloc", NoTrackYet); 1511 1512 // Create summaries QCRenderer/QCView -createSnapShotImageOfType: 1513 addInstMethSummary("QCRenderer", AllocSumm, 1514 "createSnapshotImageOfType", NULL); 1515 addInstMethSummary("QCView", AllocSumm, 1516 "createSnapshotImageOfType", NULL); 1517 1518 // Create summaries for CIContext, 'createCGImage' and 1519 // 'createCGLayerWithSize'. These objects are CF objects, and are not 1520 // automatically garbage collected. 1521 addInstMethSummary("CIContext", CFAllocSumm, 1522 "createCGImage", "fromRect", NULL); 1523 addInstMethSummary("CIContext", CFAllocSumm, 1524 "createCGImage", "fromRect", "format", "colorSpace", NULL); 1525 addInstMethSummary("CIContext", CFAllocSumm, "createCGLayerWithSize", 1526 "info", NULL); 1527} 1528 1529//===----------------------------------------------------------------------===// 1530// AutoreleaseBindings - State used to track objects in autorelease pools. 1531//===----------------------------------------------------------------------===// 1532 1533typedef llvm::ImmutableMap<SymbolRef, unsigned> ARCounts; 1534typedef llvm::ImmutableMap<SymbolRef, ARCounts> ARPoolContents; 1535typedef llvm::ImmutableList<SymbolRef> ARStack; 1536 1537static int AutoRCIndex = 0; 1538static int AutoRBIndex = 0; 1539 1540namespace { class AutoreleasePoolContents {}; } 1541namespace { class AutoreleaseStack {}; } 1542 1543namespace clang { 1544namespace ento { 1545template<> struct ProgramStateTrait<AutoreleaseStack> 1546 : public ProgramStatePartialTrait<ARStack> { 1547 static inline void *GDMIndex() { return &AutoRBIndex; } 1548}; 1549 1550template<> struct ProgramStateTrait<AutoreleasePoolContents> 1551 : public ProgramStatePartialTrait<ARPoolContents> { 1552 static inline void *GDMIndex() { return &AutoRCIndex; } 1553}; 1554} // end GR namespace 1555} // end clang namespace 1556 1557static SymbolRef GetCurrentAutoreleasePool(ProgramStateRef state) { 1558 ARStack stack = state->get<AutoreleaseStack>(); 1559 return stack.isEmpty() ? SymbolRef() : stack.getHead(); 1560} 1561 1562static ProgramStateRef 1563SendAutorelease(ProgramStateRef state, 1564 ARCounts::Factory &F, 1565 SymbolRef sym) { 1566 SymbolRef pool = GetCurrentAutoreleasePool(state); 1567 const ARCounts *cnts = state->get<AutoreleasePoolContents>(pool); 1568 ARCounts newCnts(0); 1569 1570 if (cnts) { 1571 const unsigned *cnt = (*cnts).lookup(sym); 1572 newCnts = F.add(*cnts, sym, cnt ? *cnt + 1 : 1); 1573 } 1574 else 1575 newCnts = F.add(F.getEmptyMap(), sym, 1); 1576 1577 return state->set<AutoreleasePoolContents>(pool, newCnts); 1578} 1579 1580//===----------------------------------------------------------------------===// 1581// Error reporting. 1582//===----------------------------------------------------------------------===// 1583namespace { 1584 typedef llvm::DenseMap<const ExplodedNode *, const RetainSummary *> 1585 SummaryLogTy; 1586 1587 //===-------------===// 1588 // Bug Descriptions. // 1589 //===-------------===// 1590 1591 class CFRefBug : public BugType { 1592 protected: 1593 CFRefBug(StringRef name) 1594 : BugType(name, "Memory (Core Foundation/Objective-C)") {} 1595 public: 1596 1597 // FIXME: Eventually remove. 1598 virtual const char *getDescription() const = 0; 1599 1600 virtual bool isLeak() const { return false; } 1601 }; 1602 1603 class UseAfterRelease : public CFRefBug { 1604 public: 1605 UseAfterRelease() : CFRefBug("Use-after-release") {} 1606 1607 const char *getDescription() const { 1608 return "Reference-counted object is used after it is released"; 1609 } 1610 }; 1611 1612 class BadRelease : public CFRefBug { 1613 public: 1614 BadRelease() : CFRefBug("Bad release") {} 1615 1616 const char *getDescription() const { 1617 return "Incorrect decrement of the reference count of an object that is " 1618 "not owned at this point by the caller"; 1619 } 1620 }; 1621 1622 class DeallocGC : public CFRefBug { 1623 public: 1624 DeallocGC() 1625 : CFRefBug("-dealloc called while using garbage collection") {} 1626 1627 const char *getDescription() const { 1628 return "-dealloc called while using garbage collection"; 1629 } 1630 }; 1631 1632 class DeallocNotOwned : public CFRefBug { 1633 public: 1634 DeallocNotOwned() 1635 : CFRefBug("-dealloc sent to non-exclusively owned object") {} 1636 1637 const char *getDescription() const { 1638 return "-dealloc sent to object that may be referenced elsewhere"; 1639 } 1640 }; 1641 1642 class OverAutorelease : public CFRefBug { 1643 public: 1644 OverAutorelease() 1645 : CFRefBug("Object sent -autorelease too many times") {} 1646 1647 const char *getDescription() const { 1648 return "Object sent -autorelease too many times"; 1649 } 1650 }; 1651 1652 class ReturnedNotOwnedForOwned : public CFRefBug { 1653 public: 1654 ReturnedNotOwnedForOwned() 1655 : CFRefBug("Method should return an owned object") {} 1656 1657 const char *getDescription() const { 1658 return "Object with a +0 retain count returned to caller where a +1 " 1659 "(owning) retain count is expected"; 1660 } 1661 }; 1662 1663 class Leak : public CFRefBug { 1664 const bool isReturn; 1665 protected: 1666 Leak(StringRef name, bool isRet) 1667 : CFRefBug(name), isReturn(isRet) { 1668 // Leaks should not be reported if they are post-dominated by a sink. 1669 setSuppressOnSink(true); 1670 } 1671 public: 1672 1673 const char *getDescription() const { return ""; } 1674 1675 bool isLeak() const { return true; } 1676 }; 1677 1678 class LeakAtReturn : public Leak { 1679 public: 1680 LeakAtReturn(StringRef name) 1681 : Leak(name, true) {} 1682 }; 1683 1684 class LeakWithinFunction : public Leak { 1685 public: 1686 LeakWithinFunction(StringRef name) 1687 : Leak(name, false) {} 1688 }; 1689 1690 //===---------===// 1691 // Bug Reports. // 1692 //===---------===// 1693 1694 class CFRefReportVisitor : public BugReporterVisitor { 1695 protected: 1696 SymbolRef Sym; 1697 const SummaryLogTy &SummaryLog; 1698 bool GCEnabled; 1699 1700 public: 1701 CFRefReportVisitor(SymbolRef sym, bool gcEnabled, const SummaryLogTy &log) 1702 : Sym(sym), SummaryLog(log), GCEnabled(gcEnabled) {} 1703 1704 virtual void Profile(llvm::FoldingSetNodeID &ID) const { 1705 static int x = 0; 1706 ID.AddPointer(&x); 1707 ID.AddPointer(Sym); 1708 } 1709 1710 virtual PathDiagnosticPiece *VisitNode(const ExplodedNode *N, 1711 const ExplodedNode *PrevN, 1712 BugReporterContext &BRC, 1713 BugReport &BR); 1714 1715 virtual PathDiagnosticPiece *getEndPath(BugReporterContext &BRC, 1716 const ExplodedNode *N, 1717 BugReport &BR); 1718 }; 1719 1720 class CFRefLeakReportVisitor : public CFRefReportVisitor { 1721 public: 1722 CFRefLeakReportVisitor(SymbolRef sym, bool GCEnabled, 1723 const SummaryLogTy &log) 1724 : CFRefReportVisitor(sym, GCEnabled, log) {} 1725 1726 PathDiagnosticPiece *getEndPath(BugReporterContext &BRC, 1727 const ExplodedNode *N, 1728 BugReport &BR); 1729 }; 1730 1731 class CFRefReport : public BugReport { 1732 void addGCModeDescription(const LangOptions &LOpts, bool GCEnabled); 1733 1734 public: 1735 CFRefReport(CFRefBug &D, const LangOptions &LOpts, bool GCEnabled, 1736 const SummaryLogTy &Log, ExplodedNode *n, SymbolRef sym, 1737 bool registerVisitor = true) 1738 : BugReport(D, D.getDescription(), n) { 1739 if (registerVisitor) 1740 addVisitor(new CFRefReportVisitor(sym, GCEnabled, Log)); 1741 addGCModeDescription(LOpts, GCEnabled); 1742 } 1743 1744 CFRefReport(CFRefBug &D, const LangOptions &LOpts, bool GCEnabled, 1745 const SummaryLogTy &Log, ExplodedNode *n, SymbolRef sym, 1746 StringRef endText) 1747 : BugReport(D, D.getDescription(), endText, n) { 1748 addVisitor(new CFRefReportVisitor(sym, GCEnabled, Log)); 1749 addGCModeDescription(LOpts, GCEnabled); 1750 } 1751 1752 virtual std::pair<ranges_iterator, ranges_iterator> getRanges() { 1753 const CFRefBug& BugTy = static_cast<CFRefBug&>(getBugType()); 1754 if (!BugTy.isLeak()) 1755 return BugReport::getRanges(); 1756 else 1757 return std::make_pair(ranges_iterator(), ranges_iterator()); 1758 } 1759 }; 1760 1761 class CFRefLeakReport : public CFRefReport { 1762 const MemRegion* AllocBinding; 1763 1764 public: 1765 CFRefLeakReport(CFRefBug &D, const LangOptions &LOpts, bool GCEnabled, 1766 const SummaryLogTy &Log, ExplodedNode *n, SymbolRef sym, 1767 CheckerContext &Ctx); 1768 1769 PathDiagnosticLocation getLocation(const SourceManager &SM) const { 1770 assert(Location.isValid()); 1771 return Location; 1772 } 1773 }; 1774} // end anonymous namespace 1775 1776void CFRefReport::addGCModeDescription(const LangOptions &LOpts, 1777 bool GCEnabled) { 1778 const char *GCModeDescription = 0; 1779 1780 switch (LOpts.getGC()) { 1781 case LangOptions::GCOnly: 1782 assert(GCEnabled); 1783 GCModeDescription = "Code is compiled to only use garbage collection"; 1784 break; 1785 1786 case LangOptions::NonGC: 1787 assert(!GCEnabled); 1788 GCModeDescription = "Code is compiled to use reference counts"; 1789 break; 1790 1791 case LangOptions::HybridGC: 1792 if (GCEnabled) { 1793 GCModeDescription = "Code is compiled to use either garbage collection " 1794 "(GC) or reference counts (non-GC). The bug occurs " 1795 "with GC enabled"; 1796 break; 1797 } else { 1798 GCModeDescription = "Code is compiled to use either garbage collection " 1799 "(GC) or reference counts (non-GC). The bug occurs " 1800 "in non-GC mode"; 1801 break; 1802 } 1803 } 1804 1805 assert(GCModeDescription && "invalid/unknown GC mode"); 1806 addExtraText(GCModeDescription); 1807} 1808 1809// FIXME: This should be a method on SmallVector. 1810static inline bool contains(const SmallVectorImpl<ArgEffect>& V, 1811 ArgEffect X) { 1812 for (SmallVectorImpl<ArgEffect>::const_iterator I=V.begin(), E=V.end(); 1813 I!=E; ++I) 1814 if (*I == X) return true; 1815 1816 return false; 1817} 1818 1819static bool isPropertyAccess(const Stmt *S, ParentMap &PM) { 1820 unsigned maxDepth = 4; 1821 while (S && maxDepth) { 1822 if (const PseudoObjectExpr *PO = dyn_cast<PseudoObjectExpr>(S)) { 1823 if (!isa<ObjCMessageExpr>(PO->getSyntacticForm())) 1824 return true; 1825 return false; 1826 } 1827 S = PM.getParent(S); 1828 --maxDepth; 1829 } 1830 return false; 1831} 1832 1833PathDiagnosticPiece *CFRefReportVisitor::VisitNode(const ExplodedNode *N, 1834 const ExplodedNode *PrevN, 1835 BugReporterContext &BRC, 1836 BugReport &BR) { 1837 1838 if (!isa<StmtPoint>(N->getLocation())) 1839 return NULL; 1840 1841 // Check if the type state has changed. 1842 ProgramStateRef PrevSt = PrevN->getState(); 1843 ProgramStateRef CurrSt = N->getState(); 1844 const LocationContext *LCtx = N->getLocationContext(); 1845 1846 const RefVal* CurrT = CurrSt->get<RefBindings>(Sym); 1847 if (!CurrT) return NULL; 1848 1849 const RefVal &CurrV = *CurrT; 1850 const RefVal *PrevT = PrevSt->get<RefBindings>(Sym); 1851 1852 // Create a string buffer to constain all the useful things we want 1853 // to tell the user. 1854 std::string sbuf; 1855 llvm::raw_string_ostream os(sbuf); 1856 1857 // This is the allocation site since the previous node had no bindings 1858 // for this symbol. 1859 if (!PrevT) { 1860 const Stmt *S = cast<StmtPoint>(N->getLocation()).getStmt(); 1861 1862 if (const CallExpr *CE = dyn_cast<CallExpr>(S)) { 1863 // Get the name of the callee (if it is available). 1864 SVal X = CurrSt->getSValAsScalarOrLoc(CE->getCallee(), LCtx); 1865 if (const FunctionDecl *FD = X.getAsFunctionDecl()) 1866 os << "Call to function '" << *FD << '\''; 1867 else 1868 os << "function call"; 1869 } 1870 else { 1871 assert(isa<ObjCMessageExpr>(S)); 1872 // The message expression may have between written directly or as 1873 // a property access. Lazily determine which case we are looking at. 1874 os << (isPropertyAccess(S, N->getParentMap()) ? "Property" : "Method"); 1875 } 1876 1877 if (CurrV.getObjKind() == RetEffect::CF) { 1878 os << " returns a Core Foundation object with a "; 1879 } 1880 else { 1881 assert (CurrV.getObjKind() == RetEffect::ObjC); 1882 os << " returns an Objective-C object with a "; 1883 } 1884 1885 if (CurrV.isOwned()) { 1886 os << "+1 retain count"; 1887 1888 if (GCEnabled) { 1889 assert(CurrV.getObjKind() == RetEffect::CF); 1890 os << ". " 1891 "Core Foundation objects are not automatically garbage collected."; 1892 } 1893 } 1894 else { 1895 assert (CurrV.isNotOwned()); 1896 os << "+0 retain count"; 1897 } 1898 1899 PathDiagnosticLocation Pos(S, BRC.getSourceManager(), 1900 N->getLocationContext()); 1901 return new PathDiagnosticEventPiece(Pos, os.str()); 1902 } 1903 1904 // Gather up the effects that were performed on the object at this 1905 // program point 1906 SmallVector<ArgEffect, 2> AEffects; 1907 1908 const ExplodedNode *OrigNode = BRC.getNodeResolver().getOriginalNode(N); 1909 if (const RetainSummary *Summ = SummaryLog.lookup(OrigNode)) { 1910 // We only have summaries attached to nodes after evaluating CallExpr and 1911 // ObjCMessageExprs. 1912 const Stmt *S = cast<StmtPoint>(N->getLocation()).getStmt(); 1913 1914 if (const CallExpr *CE = dyn_cast<CallExpr>(S)) { 1915 // Iterate through the parameter expressions and see if the symbol 1916 // was ever passed as an argument. 1917 unsigned i = 0; 1918 1919 for (CallExpr::const_arg_iterator AI=CE->arg_begin(), AE=CE->arg_end(); 1920 AI!=AE; ++AI, ++i) { 1921 1922 // Retrieve the value of the argument. Is it the symbol 1923 // we are interested in? 1924 if (CurrSt->getSValAsScalarOrLoc(*AI, LCtx).getAsLocSymbol() != Sym) 1925 continue; 1926 1927 // We have an argument. Get the effect! 1928 AEffects.push_back(Summ->getArg(i)); 1929 } 1930 } 1931 else if (const ObjCMessageExpr *ME = dyn_cast<ObjCMessageExpr>(S)) { 1932 if (const Expr *receiver = ME->getInstanceReceiver()) 1933 if (CurrSt->getSValAsScalarOrLoc(receiver, LCtx) 1934 .getAsLocSymbol() == Sym) { 1935 // The symbol we are tracking is the receiver. 1936 AEffects.push_back(Summ->getReceiverEffect()); 1937 } 1938 } 1939 } 1940 1941 do { 1942 // Get the previous type state. 1943 RefVal PrevV = *PrevT; 1944 1945 // Specially handle -dealloc. 1946 if (!GCEnabled && contains(AEffects, Dealloc)) { 1947 // Determine if the object's reference count was pushed to zero. 1948 assert(!(PrevV == CurrV) && "The typestate *must* have changed."); 1949 // We may not have transitioned to 'release' if we hit an error. 1950 // This case is handled elsewhere. 1951 if (CurrV.getKind() == RefVal::Released) { 1952 assert(CurrV.getCombinedCounts() == 0); 1953 os << "Object released by directly sending the '-dealloc' message"; 1954 break; 1955 } 1956 } 1957 1958 // Specially handle CFMakeCollectable and friends. 1959 if (contains(AEffects, MakeCollectable)) { 1960 // Get the name of the function. 1961 const Stmt *S = cast<StmtPoint>(N->getLocation()).getStmt(); 1962 SVal X = 1963 CurrSt->getSValAsScalarOrLoc(cast<CallExpr>(S)->getCallee(), LCtx); 1964 const FunctionDecl *FD = X.getAsFunctionDecl(); 1965 1966 if (GCEnabled) { 1967 // Determine if the object's reference count was pushed to zero. 1968 assert(!(PrevV == CurrV) && "The typestate *must* have changed."); 1969 1970 os << "In GC mode a call to '" << *FD 1971 << "' decrements an object's retain count and registers the " 1972 "object with the garbage collector. "; 1973 1974 if (CurrV.getKind() == RefVal::Released) { 1975 assert(CurrV.getCount() == 0); 1976 os << "Since it now has a 0 retain count the object can be " 1977 "automatically collected by the garbage collector."; 1978 } 1979 else 1980 os << "An object must have a 0 retain count to be garbage collected. " 1981 "After this call its retain count is +" << CurrV.getCount() 1982 << '.'; 1983 } 1984 else 1985 os << "When GC is not enabled a call to '" << *FD 1986 << "' has no effect on its argument."; 1987 1988 // Nothing more to say. 1989 break; 1990 } 1991 1992 // Determine if the typestate has changed. 1993 if (!(PrevV == CurrV)) 1994 switch (CurrV.getKind()) { 1995 case RefVal::Owned: 1996 case RefVal::NotOwned: 1997 1998 if (PrevV.getCount() == CurrV.getCount()) { 1999 // Did an autorelease message get sent? 2000 if (PrevV.getAutoreleaseCount() == CurrV.getAutoreleaseCount()) 2001 return 0; 2002 2003 assert(PrevV.getAutoreleaseCount() < CurrV.getAutoreleaseCount()); 2004 os << "Object sent -autorelease message"; 2005 break; 2006 } 2007 2008 if (PrevV.getCount() > CurrV.getCount()) 2009 os << "Reference count decremented."; 2010 else 2011 os << "Reference count incremented."; 2012 2013 if (unsigned Count = CurrV.getCount()) 2014 os << " The object now has a +" << Count << " retain count."; 2015 2016 if (PrevV.getKind() == RefVal::Released) { 2017 assert(GCEnabled && CurrV.getCount() > 0); 2018 os << " The object is not eligible for garbage collection until the " 2019 "retain count reaches 0 again."; 2020 } 2021 2022 break; 2023 2024 case RefVal::Released: 2025 os << "Object released."; 2026 break; 2027 2028 case RefVal::ReturnedOwned: 2029 os << "Object returned to caller as an owning reference (single retain " 2030 "count transferred to caller)"; 2031 break; 2032 2033 case RefVal::ReturnedNotOwned: 2034 os << "Object returned to caller with a +0 retain count"; 2035 break; 2036 2037 default: 2038 return NULL; 2039 } 2040 2041 // Emit any remaining diagnostics for the argument effects (if any). 2042 for (SmallVectorImpl<ArgEffect>::iterator I=AEffects.begin(), 2043 E=AEffects.end(); I != E; ++I) { 2044 2045 // A bunch of things have alternate behavior under GC. 2046 if (GCEnabled) 2047 switch (*I) { 2048 default: break; 2049 case Autorelease: 2050 os << "In GC mode an 'autorelease' has no effect."; 2051 continue; 2052 case IncRefMsg: 2053 os << "In GC mode the 'retain' message has no effect."; 2054 continue; 2055 case DecRefMsg: 2056 os << "In GC mode the 'release' message has no effect."; 2057 continue; 2058 } 2059 } 2060 } while (0); 2061 2062 if (os.str().empty()) 2063 return 0; // We have nothing to say! 2064 2065 const Stmt *S = cast<StmtPoint>(N->getLocation()).getStmt(); 2066 PathDiagnosticLocation Pos(S, BRC.getSourceManager(), 2067 N->getLocationContext()); 2068 PathDiagnosticPiece *P = new PathDiagnosticEventPiece(Pos, os.str()); 2069 2070 // Add the range by scanning the children of the statement for any bindings 2071 // to Sym. 2072 for (Stmt::const_child_iterator I = S->child_begin(), E = S->child_end(); 2073 I!=E; ++I) 2074 if (const Expr *Exp = dyn_cast_or_null<Expr>(*I)) 2075 if (CurrSt->getSValAsScalarOrLoc(Exp, LCtx).getAsLocSymbol() == Sym) { 2076 P->addRange(Exp->getSourceRange()); 2077 break; 2078 } 2079 2080 return P; 2081} 2082 2083namespace { 2084 class FindUniqueBinding : 2085 public StoreManager::BindingsHandler { 2086 SymbolRef Sym; 2087 const MemRegion* Binding; 2088 bool First; 2089 2090 public: 2091 FindUniqueBinding(SymbolRef sym) : Sym(sym), Binding(0), First(true) {} 2092 2093 bool HandleBinding(StoreManager& SMgr, Store store, const MemRegion* R, 2094 SVal val) { 2095 2096 SymbolRef SymV = val.getAsSymbol(); 2097 if (!SymV || SymV != Sym) 2098 return true; 2099 2100 if (Binding) { 2101 First = false; 2102 return false; 2103 } 2104 else 2105 Binding = R; 2106 2107 return true; 2108 } 2109 2110 operator bool() { return First && Binding; } 2111 const MemRegion *getRegion() { return Binding; } 2112 }; 2113} 2114 2115static std::pair<const ExplodedNode*,const MemRegion*> 2116GetAllocationSite(ProgramStateManager& StateMgr, const ExplodedNode *N, 2117 SymbolRef Sym) { 2118 2119 // Find both first node that referred to the tracked symbol and the 2120 // memory location that value was store to. 2121 const ExplodedNode *Last = N; 2122 const MemRegion* FirstBinding = 0; 2123 2124 while (N) { 2125 ProgramStateRef St = N->getState(); 2126 RefBindings B = St->get<RefBindings>(); 2127 2128 if (!B.lookup(Sym)) 2129 break; 2130 2131 FindUniqueBinding FB(Sym); 2132 StateMgr.iterBindings(St, FB); 2133 if (FB) FirstBinding = FB.getRegion(); 2134 2135 Last = N; 2136 N = N->pred_empty() ? NULL : *(N->pred_begin()); 2137 } 2138 2139 return std::make_pair(Last, FirstBinding); 2140} 2141 2142PathDiagnosticPiece* 2143CFRefReportVisitor::getEndPath(BugReporterContext &BRC, 2144 const ExplodedNode *EndN, 2145 BugReport &BR) { 2146 // Tell the BugReporterContext to report cases when the tracked symbol is 2147 // assigned to different variables, etc. 2148 BRC.addNotableSymbol(Sym); 2149 return BugReporterVisitor::getDefaultEndPath(BRC, EndN, BR); 2150} 2151 2152PathDiagnosticPiece* 2153CFRefLeakReportVisitor::getEndPath(BugReporterContext &BRC, 2154 const ExplodedNode *EndN, 2155 BugReport &BR) { 2156 2157 // Tell the BugReporterContext to report cases when the tracked symbol is 2158 // assigned to different variables, etc. 2159 BRC.addNotableSymbol(Sym); 2160 2161 // We are reporting a leak. Walk up the graph to get to the first node where 2162 // the symbol appeared, and also get the first VarDecl that tracked object 2163 // is stored to. 2164 const ExplodedNode *AllocNode = 0; 2165 const MemRegion* FirstBinding = 0; 2166 2167 llvm::tie(AllocNode, FirstBinding) = 2168 GetAllocationSite(BRC.getStateManager(), EndN, Sym); 2169 2170 SourceManager& SM = BRC.getSourceManager(); 2171 2172 // Compute an actual location for the leak. Sometimes a leak doesn't 2173 // occur at an actual statement (e.g., transition between blocks; end 2174 // of function) so we need to walk the graph and compute a real location. 2175 const ExplodedNode *LeakN = EndN; 2176 PathDiagnosticLocation L = PathDiagnosticLocation::createEndOfPath(LeakN, SM); 2177 2178 std::string sbuf; 2179 llvm::raw_string_ostream os(sbuf); 2180 2181 os << "Object leaked: "; 2182 2183 if (FirstBinding) { 2184 os << "object allocated and stored into '" 2185 << FirstBinding->getString() << '\''; 2186 } 2187 else 2188 os << "allocated object"; 2189 2190 // Get the retain count. 2191 const RefVal* RV = EndN->getState()->get<RefBindings>(Sym); 2192 2193 if (RV->getKind() == RefVal::ErrorLeakReturned) { 2194 // FIXME: Per comments in rdar://6320065, "create" only applies to CF 2195 // objects. Only "copy", "alloc", "retain" and "new" transfer ownership 2196 // to the caller for NS objects. 2197 const Decl *D = &EndN->getCodeDecl(); 2198 if (const ObjCMethodDecl *MD = dyn_cast<ObjCMethodDecl>(D)) { 2199 os << " is returned from a method whose name ('" 2200 << MD->getSelector().getAsString() 2201 << "') does not start with 'copy', 'mutableCopy', 'alloc' or 'new'." 2202 " This violates the naming convention rules" 2203 " given in the Memory Management Guide for Cocoa"; 2204 } 2205 else { 2206 const FunctionDecl *FD = cast<FunctionDecl>(D); 2207 os << " is returned from a function whose name ('" 2208 << *FD 2209 << "') does not contain 'Copy' or 'Create'. This violates the naming" 2210 " convention rules given in the Memory Management Guide for Core" 2211 " Foundation"; 2212 } 2213 } 2214 else if (RV->getKind() == RefVal::ErrorGCLeakReturned) { 2215 ObjCMethodDecl &MD = cast<ObjCMethodDecl>(EndN->getCodeDecl()); 2216 os << " and returned from method '" << MD.getSelector().getAsString() 2217 << "' is potentially leaked when using garbage collection. Callers " 2218 "of this method do not expect a returned object with a +1 retain " 2219 "count since they expect the object to be managed by the garbage " 2220 "collector"; 2221 } 2222 else 2223 os << " is not referenced later in this execution path and has a retain " 2224 "count of +" << RV->getCount(); 2225 2226 return new PathDiagnosticEventPiece(L, os.str()); 2227} 2228 2229CFRefLeakReport::CFRefLeakReport(CFRefBug &D, const LangOptions &LOpts, 2230 bool GCEnabled, const SummaryLogTy &Log, 2231 ExplodedNode *n, SymbolRef sym, 2232 CheckerContext &Ctx) 2233: CFRefReport(D, LOpts, GCEnabled, Log, n, sym, false) { 2234 2235 // Most bug reports are cached at the location where they occurred. 2236 // With leaks, we want to unique them by the location where they were 2237 // allocated, and only report a single path. To do this, we need to find 2238 // the allocation site of a piece of tracked memory, which we do via a 2239 // call to GetAllocationSite. This will walk the ExplodedGraph backwards. 2240 // Note that this is *not* the trimmed graph; we are guaranteed, however, 2241 // that all ancestor nodes that represent the allocation site have the 2242 // same SourceLocation. 2243 const ExplodedNode *AllocNode = 0; 2244 2245 const SourceManager& SMgr = Ctx.getSourceManager(); 2246 2247 llvm::tie(AllocNode, AllocBinding) = // Set AllocBinding. 2248 GetAllocationSite(Ctx.getStateManager(), getErrorNode(), sym); 2249 2250 // Get the SourceLocation for the allocation site. 2251 ProgramPoint P = AllocNode->getLocation(); 2252 const Stmt *AllocStmt = cast<PostStmt>(P).getStmt(); 2253 Location = PathDiagnosticLocation::createBegin(AllocStmt, SMgr, 2254 n->getLocationContext()); 2255 // Fill in the description of the bug. 2256 Description.clear(); 2257 llvm::raw_string_ostream os(Description); 2258 unsigned AllocLine = SMgr.getExpansionLineNumber(AllocStmt->getLocStart()); 2259 os << "Potential leak "; 2260 if (GCEnabled) 2261 os << "(when using garbage collection) "; 2262 os << "of an object allocated on line " << AllocLine; 2263 2264 // FIXME: AllocBinding doesn't get populated for RegionStore yet. 2265 if (AllocBinding) 2266 os << " and stored into '" << AllocBinding->getString() << '\''; 2267 2268 addVisitor(new CFRefLeakReportVisitor(sym, GCEnabled, Log)); 2269} 2270 2271//===----------------------------------------------------------------------===// 2272// Main checker logic. 2273//===----------------------------------------------------------------------===// 2274 2275namespace { 2276class RetainCountChecker 2277 : public Checker< check::Bind, 2278 check::DeadSymbols, 2279 check::EndAnalysis, 2280 check::EndPath, 2281 check::PostStmt<BlockExpr>, 2282 check::PostStmt<CastExpr>, 2283 check::PostStmt<CallExpr>, 2284 check::PostStmt<CXXConstructExpr>, 2285 check::PostObjCMessage, 2286 check::PreStmt<ReturnStmt>, 2287 check::RegionChanges, 2288 eval::Assume, 2289 eval::Call > { 2290 mutable OwningPtr<CFRefBug> useAfterRelease, releaseNotOwned; 2291 mutable OwningPtr<CFRefBug> deallocGC, deallocNotOwned; 2292 mutable OwningPtr<CFRefBug> overAutorelease, returnNotOwnedForOwned; 2293 mutable OwningPtr<CFRefBug> leakWithinFunction, leakAtReturn; 2294 mutable OwningPtr<CFRefBug> leakWithinFunctionGC, leakAtReturnGC; 2295 2296 typedef llvm::DenseMap<SymbolRef, const SimpleProgramPointTag *> SymbolTagMap; 2297 2298 // This map is only used to ensure proper deletion of any allocated tags. 2299 mutable SymbolTagMap DeadSymbolTags; 2300 2301 mutable OwningPtr<RetainSummaryManager> Summaries; 2302 mutable OwningPtr<RetainSummaryManager> SummariesGC; 2303 2304 mutable ARCounts::Factory ARCountFactory; 2305 2306 mutable SummaryLogTy SummaryLog; 2307 mutable bool ShouldResetSummaryLog; 2308 2309public: 2310 RetainCountChecker() : ShouldResetSummaryLog(false) {} 2311 2312 virtual ~RetainCountChecker() { 2313 DeleteContainerSeconds(DeadSymbolTags); 2314 } 2315 2316 void checkEndAnalysis(ExplodedGraph &G, BugReporter &BR, 2317 ExprEngine &Eng) const { 2318 // FIXME: This is a hack to make sure the summary log gets cleared between 2319 // analyses of different code bodies. 2320 // 2321 // Why is this necessary? Because a checker's lifetime is tied to a 2322 // translation unit, but an ExplodedGraph's lifetime is just a code body. 2323 // Once in a blue moon, a new ExplodedNode will have the same address as an 2324 // old one with an associated summary, and the bug report visitor gets very 2325 // confused. (To make things worse, the summary lifetime is currently also 2326 // tied to a code body, so we get a crash instead of incorrect results.) 2327 // 2328 // Why is this a bad solution? Because if the lifetime of the ExplodedGraph 2329 // changes, things will start going wrong again. Really the lifetime of this 2330 // log needs to be tied to either the specific nodes in it or the entire 2331 // ExplodedGraph, not to a specific part of the code being analyzed. 2332 // 2333 // (Also, having stateful local data means that the same checker can't be 2334 // used from multiple threads, but a lot of checkers have incorrect 2335 // assumptions about that anyway. So that wasn't a priority at the time of 2336 // this fix.) 2337 // 2338 // This happens at the end of analysis, but bug reports are emitted /after/ 2339 // this point. So we can't just clear the summary log now. Instead, we mark 2340 // that the next time we access the summary log, it should be cleared. 2341 2342 // If we never reset the summary log during /this/ code body analysis, 2343 // there were no new summaries. There might still have been summaries from 2344 // the /last/ analysis, so clear them out to make sure the bug report 2345 // visitors don't get confused. 2346 if (ShouldResetSummaryLog) 2347 SummaryLog.clear(); 2348 2349 ShouldResetSummaryLog = !SummaryLog.empty(); 2350 } 2351 2352 CFRefBug *getLeakWithinFunctionBug(const LangOptions &LOpts, 2353 bool GCEnabled) const { 2354 if (GCEnabled) { 2355 if (!leakWithinFunctionGC) 2356 leakWithinFunctionGC.reset(new LeakWithinFunction("Leak of object when " 2357 "using garbage " 2358 "collection")); 2359 return leakWithinFunctionGC.get(); 2360 } else { 2361 if (!leakWithinFunction) { 2362 if (LOpts.getGC() == LangOptions::HybridGC) { 2363 leakWithinFunction.reset(new LeakWithinFunction("Leak of object when " 2364 "not using garbage " 2365 "collection (GC) in " 2366 "dual GC/non-GC " 2367 "code")); 2368 } else { 2369 leakWithinFunction.reset(new LeakWithinFunction("Leak")); 2370 } 2371 } 2372 return leakWithinFunction.get(); 2373 } 2374 } 2375 2376 CFRefBug *getLeakAtReturnBug(const LangOptions &LOpts, bool GCEnabled) const { 2377 if (GCEnabled) { 2378 if (!leakAtReturnGC) 2379 leakAtReturnGC.reset(new LeakAtReturn("Leak of returned object when " 2380 "using garbage collection")); 2381 return leakAtReturnGC.get(); 2382 } else { 2383 if (!leakAtReturn) { 2384 if (LOpts.getGC() == LangOptions::HybridGC) { 2385 leakAtReturn.reset(new LeakAtReturn("Leak of returned object when " 2386 "not using garbage collection " 2387 "(GC) in dual GC/non-GC code")); 2388 } else { 2389 leakAtReturn.reset(new LeakAtReturn("Leak of returned object")); 2390 } 2391 } 2392 return leakAtReturn.get(); 2393 } 2394 } 2395 2396 RetainSummaryManager &getSummaryManager(ASTContext &Ctx, 2397 bool GCEnabled) const { 2398 // FIXME: We don't support ARC being turned on and off during one analysis. 2399 // (nor, for that matter, do we support changing ASTContexts) 2400 bool ARCEnabled = (bool)Ctx.getLangOptions().ObjCAutoRefCount; 2401 if (GCEnabled) { 2402 if (!SummariesGC) 2403 SummariesGC.reset(new RetainSummaryManager(Ctx, true, ARCEnabled)); 2404 else 2405 assert(SummariesGC->isARCEnabled() == ARCEnabled); 2406 return *SummariesGC; 2407 } else { 2408 if (!Summaries) 2409 Summaries.reset(new RetainSummaryManager(Ctx, false, ARCEnabled)); 2410 else 2411 assert(Summaries->isARCEnabled() == ARCEnabled); 2412 return *Summaries; 2413 } 2414 } 2415 2416 RetainSummaryManager &getSummaryManager(CheckerContext &C) const { 2417 return getSummaryManager(C.getASTContext(), C.isObjCGCEnabled()); 2418 } 2419 2420 void printState(raw_ostream &Out, ProgramStateRef State, 2421 const char *NL, const char *Sep) const; 2422 2423 void checkBind(SVal loc, SVal val, const Stmt *S, CheckerContext &C) const; 2424 void checkPostStmt(const BlockExpr *BE, CheckerContext &C) const; 2425 void checkPostStmt(const CastExpr *CE, CheckerContext &C) const; 2426 2427 void checkPostStmt(const CallExpr *CE, CheckerContext &C) const; 2428 void checkPostStmt(const CXXConstructExpr *CE, CheckerContext &C) const; 2429 void checkPostObjCMessage(const ObjCMessage &Msg, CheckerContext &C) const; 2430 void checkSummary(const RetainSummary &Summ, const CallOrObjCMessage &Call, 2431 CheckerContext &C) const; 2432 2433 bool evalCall(const CallExpr *CE, CheckerContext &C) const; 2434 2435 ProgramStateRef evalAssume(ProgramStateRef state, SVal Cond, 2436 bool Assumption) const; 2437 2438 ProgramStateRef 2439 checkRegionChanges(ProgramStateRef state, 2440 const StoreManager::InvalidatedSymbols *invalidated, 2441 ArrayRef<const MemRegion *> ExplicitRegions, 2442 ArrayRef<const MemRegion *> Regions, 2443 const CallOrObjCMessage *Call) const; 2444 2445 bool wantsRegionChangeUpdate(ProgramStateRef state) const { 2446 return true; 2447 } 2448 2449 void checkPreStmt(const ReturnStmt *S, CheckerContext &C) const; 2450 void checkReturnWithRetEffect(const ReturnStmt *S, CheckerContext &C, 2451 ExplodedNode *Pred, RetEffect RE, RefVal X, 2452 SymbolRef Sym, ProgramStateRef state) const; 2453 2454 void checkDeadSymbols(SymbolReaper &SymReaper, CheckerContext &C) const; 2455 void checkEndPath(CheckerContext &C) const; 2456 2457 ProgramStateRef updateSymbol(ProgramStateRef state, SymbolRef sym, 2458 RefVal V, ArgEffect E, RefVal::Kind &hasErr, 2459 CheckerContext &C) const; 2460 2461 void processNonLeakError(ProgramStateRef St, SourceRange ErrorRange, 2462 RefVal::Kind ErrorKind, SymbolRef Sym, 2463 CheckerContext &C) const; 2464 2465 const ProgramPointTag *getDeadSymbolTag(SymbolRef sym) const; 2466 2467 ProgramStateRef handleSymbolDeath(ProgramStateRef state, 2468 SymbolRef sid, RefVal V, 2469 SmallVectorImpl<SymbolRef> &Leaked) const; 2470 2471 std::pair<ExplodedNode *, ProgramStateRef > 2472 handleAutoreleaseCounts(ProgramStateRef state, 2473 GenericNodeBuilderRefCount Bd, ExplodedNode *Pred, 2474 CheckerContext &Ctx, SymbolRef Sym, RefVal V) const; 2475 2476 ExplodedNode *processLeaks(ProgramStateRef state, 2477 SmallVectorImpl<SymbolRef> &Leaked, 2478 GenericNodeBuilderRefCount &Builder, 2479 CheckerContext &Ctx, 2480 ExplodedNode *Pred = 0) const; 2481}; 2482} // end anonymous namespace 2483 2484namespace { 2485class StopTrackingCallback : public SymbolVisitor { 2486 ProgramStateRef state; 2487public: 2488 StopTrackingCallback(ProgramStateRef st) : state(st) {} 2489 ProgramStateRef getState() const { return state; } 2490 2491 bool VisitSymbol(SymbolRef sym) { 2492 state = state->remove<RefBindings>(sym); 2493 return true; 2494 } 2495}; 2496} // end anonymous namespace 2497 2498//===----------------------------------------------------------------------===// 2499// Handle statements that may have an effect on refcounts. 2500//===----------------------------------------------------------------------===// 2501 2502void RetainCountChecker::checkPostStmt(const BlockExpr *BE, 2503 CheckerContext &C) const { 2504 2505 // Scan the BlockDecRefExprs for any object the retain count checker 2506 // may be tracking. 2507 if (!BE->getBlockDecl()->hasCaptures()) 2508 return; 2509 2510 ProgramStateRef state = C.getState(); 2511 const BlockDataRegion *R = 2512 cast<BlockDataRegion>(state->getSVal(BE, 2513 C.getLocationContext()).getAsRegion()); 2514 2515 BlockDataRegion::referenced_vars_iterator I = R->referenced_vars_begin(), 2516 E = R->referenced_vars_end(); 2517 2518 if (I == E) 2519 return; 2520 2521 // FIXME: For now we invalidate the tracking of all symbols passed to blocks 2522 // via captured variables, even though captured variables result in a copy 2523 // and in implicit increment/decrement of a retain count. 2524 SmallVector<const MemRegion*, 10> Regions; 2525 const LocationContext *LC = C.getLocationContext(); 2526 MemRegionManager &MemMgr = C.getSValBuilder().getRegionManager(); 2527 2528 for ( ; I != E; ++I) { 2529 const VarRegion *VR = *I; 2530 if (VR->getSuperRegion() == R) { 2531 VR = MemMgr.getVarRegion(VR->getDecl(), LC); 2532 } 2533 Regions.push_back(VR); 2534 } 2535 2536 state = 2537 state->scanReachableSymbols<StopTrackingCallback>(Regions.data(), 2538 Regions.data() + Regions.size()).getState(); 2539 C.addTransition(state); 2540} 2541 2542void RetainCountChecker::checkPostStmt(const CastExpr *CE, 2543 CheckerContext &C) const { 2544 const ObjCBridgedCastExpr *BE = dyn_cast<ObjCBridgedCastExpr>(CE); 2545 if (!BE) 2546 return; 2547 2548 ArgEffect AE = IncRef; 2549 2550 switch (BE->getBridgeKind()) { 2551 case clang::OBC_Bridge: 2552 // Do nothing. 2553 return; 2554 case clang::OBC_BridgeRetained: 2555 AE = IncRef; 2556 break; 2557 case clang::OBC_BridgeTransfer: 2558 AE = DecRefBridgedTransfered; 2559 break; 2560 } 2561 2562 ProgramStateRef state = C.getState(); 2563 SymbolRef Sym = state->getSVal(CE, C.getLocationContext()).getAsLocSymbol(); 2564 if (!Sym) 2565 return; 2566 const RefVal* T = state->get<RefBindings>(Sym); 2567 if (!T) 2568 return; 2569 2570 RefVal::Kind hasErr = (RefVal::Kind) 0; 2571 state = updateSymbol(state, Sym, *T, AE, hasErr, C); 2572 2573 if (hasErr) { 2574 // FIXME: If we get an error during a bridge cast, should we report it? 2575 // Should we assert that there is no error? 2576 return; 2577 } 2578 2579 C.addTransition(state); 2580} 2581 2582void RetainCountChecker::checkPostStmt(const CallExpr *CE, 2583 CheckerContext &C) const { 2584 // Get the callee. 2585 ProgramStateRef state = C.getState(); 2586 const Expr *Callee = CE->getCallee(); 2587 SVal L = state->getSVal(Callee, C.getLocationContext()); 2588 2589 RetainSummaryManager &Summaries = getSummaryManager(C); 2590 const RetainSummary *Summ = 0; 2591 2592 // FIXME: Better support for blocks. For now we stop tracking anything 2593 // that is passed to blocks. 2594 // FIXME: Need to handle variables that are "captured" by the block. 2595 if (dyn_cast_or_null<BlockDataRegion>(L.getAsRegion())) { 2596 Summ = Summaries.getPersistentStopSummary(); 2597 } else if (const FunctionDecl *FD = L.getAsFunctionDecl()) { 2598 Summ = Summaries.getSummary(FD); 2599 } else if (const CXXMemberCallExpr *me = dyn_cast<CXXMemberCallExpr>(CE)) { 2600 if (const CXXMethodDecl *MD = me->getMethodDecl()) 2601 Summ = Summaries.getSummary(MD); 2602 } 2603 2604 if (!Summ) 2605 Summ = Summaries.getDefaultSummary(); 2606 2607 checkSummary(*Summ, CallOrObjCMessage(CE, state, C.getLocationContext()), C); 2608} 2609 2610void RetainCountChecker::checkPostStmt(const CXXConstructExpr *CE, 2611 CheckerContext &C) const { 2612 const CXXConstructorDecl *Ctor = CE->getConstructor(); 2613 if (!Ctor) 2614 return; 2615 2616 RetainSummaryManager &Summaries = getSummaryManager(C); 2617 const RetainSummary *Summ = Summaries.getSummary(Ctor); 2618 2619 // If we didn't get a summary, this constructor doesn't affect retain counts. 2620 if (!Summ) 2621 return; 2622 2623 ProgramStateRef state = C.getState(); 2624 checkSummary(*Summ, CallOrObjCMessage(CE, state, C.getLocationContext()), C); 2625} 2626 2627void RetainCountChecker::checkPostObjCMessage(const ObjCMessage &Msg, 2628 CheckerContext &C) const { 2629 ProgramStateRef state = C.getState(); 2630 2631 RetainSummaryManager &Summaries = getSummaryManager(C); 2632 2633 const RetainSummary *Summ; 2634 if (Msg.isInstanceMessage()) { 2635 const LocationContext *LC = C.getLocationContext(); 2636 Summ = Summaries.getInstanceMethodSummary(Msg, state, LC); 2637 } else { 2638 Summ = Summaries.getClassMethodSummary(Msg); 2639 } 2640 2641 // If we didn't get a summary, this message doesn't affect retain counts. 2642 if (!Summ) 2643 return; 2644 2645 checkSummary(*Summ, CallOrObjCMessage(Msg, state, C.getLocationContext()), C); 2646} 2647 2648/// GetReturnType - Used to get the return type of a message expression or 2649/// function call with the intention of affixing that type to a tracked symbol. 2650/// While the the return type can be queried directly from RetEx, when 2651/// invoking class methods we augment to the return type to be that of 2652/// a pointer to the class (as opposed it just being id). 2653// FIXME: We may be able to do this with related result types instead. 2654// This function is probably overestimating. 2655static QualType GetReturnType(const Expr *RetE, ASTContext &Ctx) { 2656 QualType RetTy = RetE->getType(); 2657 // If RetE is not a message expression just return its type. 2658 // If RetE is a message expression, return its types if it is something 2659 /// more specific than id. 2660 if (const ObjCMessageExpr *ME = dyn_cast<ObjCMessageExpr>(RetE)) 2661 if (const ObjCObjectPointerType *PT = RetTy->getAs<ObjCObjectPointerType>()) 2662 if (PT->isObjCQualifiedIdType() || PT->isObjCIdType() || 2663 PT->isObjCClassType()) { 2664 // At this point we know the return type of the message expression is 2665 // id, id<...>, or Class. If we have an ObjCInterfaceDecl, we know this 2666 // is a call to a class method whose type we can resolve. In such 2667 // cases, promote the return type to XXX* (where XXX is the class). 2668 const ObjCInterfaceDecl *D = ME->getReceiverInterface(); 2669 return !D ? RetTy : 2670 Ctx.getObjCObjectPointerType(Ctx.getObjCInterfaceType(D)); 2671 } 2672 2673 return RetTy; 2674} 2675 2676void RetainCountChecker::checkSummary(const RetainSummary &Summ, 2677 const CallOrObjCMessage &CallOrMsg, 2678 CheckerContext &C) const { 2679 ProgramStateRef state = C.getState(); 2680 2681 // Evaluate the effect of the arguments. 2682 RefVal::Kind hasErr = (RefVal::Kind) 0; 2683 SourceRange ErrorRange; 2684 SymbolRef ErrorSym = 0; 2685 2686 for (unsigned idx = 0, e = CallOrMsg.getNumArgs(); idx != e; ++idx) { 2687 SVal V = CallOrMsg.getArgSVal(idx); 2688 2689 if (SymbolRef Sym = V.getAsLocSymbol()) { 2690 if (RefBindings::data_type *T = state->get<RefBindings>(Sym)) { 2691 state = updateSymbol(state, Sym, *T, Summ.getArg(idx), hasErr, C); 2692 if (hasErr) { 2693 ErrorRange = CallOrMsg.getArgSourceRange(idx); 2694 ErrorSym = Sym; 2695 break; 2696 } 2697 } 2698 } 2699 } 2700 2701 // Evaluate the effect on the message receiver. 2702 bool ReceiverIsTracked = false; 2703 if (!hasErr && CallOrMsg.isObjCMessage()) { 2704 const LocationContext *LC = C.getLocationContext(); 2705 SVal Receiver = CallOrMsg.getInstanceMessageReceiver(LC); 2706 if (SymbolRef Sym = Receiver.getAsLocSymbol()) { 2707 if (const RefVal *T = state->get<RefBindings>(Sym)) { 2708 ReceiverIsTracked = true; 2709 state = updateSymbol(state, Sym, *T, Summ.getReceiverEffect(), 2710 hasErr, C); 2711 if (hasErr) { 2712 ErrorRange = CallOrMsg.getReceiverSourceRange(); 2713 ErrorSym = Sym; 2714 } 2715 } 2716 } 2717 } 2718 2719 // Process any errors. 2720 if (hasErr) { 2721 processNonLeakError(state, ErrorRange, hasErr, ErrorSym, C); 2722 return; 2723 } 2724 2725 // Consult the summary for the return value. 2726 RetEffect RE = Summ.getRetEffect(); 2727 2728 if (RE.getKind() == RetEffect::OwnedWhenTrackedReceiver) { 2729 if (ReceiverIsTracked) 2730 RE = getSummaryManager(C).getObjAllocRetEffect(); 2731 else 2732 RE = RetEffect::MakeNoRet(); 2733 } 2734 2735 switch (RE.getKind()) { 2736 default: 2737 llvm_unreachable("Unhandled RetEffect."); 2738 2739 case RetEffect::NoRet: 2740 // No work necessary. 2741 break; 2742 2743 case RetEffect::OwnedAllocatedSymbol: 2744 case RetEffect::OwnedSymbol: { 2745 SymbolRef Sym = state->getSVal(CallOrMsg.getOriginExpr(), 2746 C.getLocationContext()).getAsSymbol(); 2747 if (!Sym) 2748 break; 2749 2750 // Use the result type from callOrMsg as it automatically adjusts 2751 // for methods/functions that return references. 2752 QualType ResultTy = CallOrMsg.getResultType(C.getASTContext()); 2753 state = state->set<RefBindings>(Sym, RefVal::makeOwned(RE.getObjKind(), 2754 ResultTy)); 2755 2756 // FIXME: Add a flag to the checker where allocations are assumed to 2757 // *not* fail. (The code below is out-of-date, though.) 2758#if 0 2759 if (RE.getKind() == RetEffect::OwnedAllocatedSymbol) { 2760 bool isFeasible; 2761 state = state.assume(loc::SymbolVal(Sym), true, isFeasible); 2762 assert(isFeasible && "Cannot assume fresh symbol is non-null."); 2763 } 2764#endif 2765 2766 break; 2767 } 2768 2769 case RetEffect::GCNotOwnedSymbol: 2770 case RetEffect::ARCNotOwnedSymbol: 2771 case RetEffect::NotOwnedSymbol: { 2772 const Expr *Ex = CallOrMsg.getOriginExpr(); 2773 SymbolRef Sym = state->getSVal(Ex, C.getLocationContext()).getAsSymbol(); 2774 if (!Sym) 2775 break; 2776 2777 // Use GetReturnType in order to give [NSFoo alloc] the type NSFoo *. 2778 QualType ResultTy = GetReturnType(Ex, C.getASTContext()); 2779 state = state->set<RefBindings>(Sym, RefVal::makeNotOwned(RE.getObjKind(), 2780 ResultTy)); 2781 break; 2782 } 2783 } 2784 2785 // This check is actually necessary; otherwise the statement builder thinks 2786 // we've hit a previously-found path. 2787 // Normally addTransition takes care of this, but we want the node pointer. 2788 ExplodedNode *NewNode; 2789 if (state == C.getState()) { 2790 NewNode = C.getPredecessor(); 2791 } else { 2792 NewNode = C.addTransition(state); 2793 } 2794 2795 // Annotate the node with summary we used. 2796 if (NewNode) { 2797 // FIXME: This is ugly. See checkEndAnalysis for why it's necessary. 2798 if (ShouldResetSummaryLog) { 2799 SummaryLog.clear(); 2800 ShouldResetSummaryLog = false; 2801 } 2802 SummaryLog[NewNode] = &Summ; 2803 } 2804} 2805 2806 2807ProgramStateRef 2808RetainCountChecker::updateSymbol(ProgramStateRef state, SymbolRef sym, 2809 RefVal V, ArgEffect E, RefVal::Kind &hasErr, 2810 CheckerContext &C) const { 2811 // In GC mode [... release] and [... retain] do nothing. 2812 // In ARC mode they shouldn't exist at all, but we just ignore them. 2813 bool IgnoreRetainMsg = C.isObjCGCEnabled(); 2814 if (!IgnoreRetainMsg) 2815 IgnoreRetainMsg = (bool)C.getASTContext().getLangOptions().ObjCAutoRefCount; 2816 2817 switch (E) { 2818 default: break; 2819 case IncRefMsg: E = IgnoreRetainMsg ? DoNothing : IncRef; break; 2820 case DecRefMsg: E = IgnoreRetainMsg ? DoNothing : DecRef; break; 2821 case MakeCollectable: E = C.isObjCGCEnabled() ? DecRef : DoNothing; break; 2822 case NewAutoreleasePool: E = C.isObjCGCEnabled() ? DoNothing : 2823 NewAutoreleasePool; break; 2824 } 2825 2826 // Handle all use-after-releases. 2827 if (!C.isObjCGCEnabled() && V.getKind() == RefVal::Released) { 2828 V = V ^ RefVal::ErrorUseAfterRelease; 2829 hasErr = V.getKind(); 2830 return state->set<RefBindings>(sym, V); 2831 } 2832 2833 switch (E) { 2834 case DecRefMsg: 2835 case IncRefMsg: 2836 case MakeCollectable: 2837 llvm_unreachable("DecRefMsg/IncRefMsg/MakeCollectable already converted"); 2838 2839 case Dealloc: 2840 // Any use of -dealloc in GC is *bad*. 2841 if (C.isObjCGCEnabled()) { 2842 V = V ^ RefVal::ErrorDeallocGC; 2843 hasErr = V.getKind(); 2844 break; 2845 } 2846 2847 switch (V.getKind()) { 2848 default: 2849 llvm_unreachable("Invalid RefVal state for an explicit dealloc."); 2850 case RefVal::Owned: 2851 // The object immediately transitions to the released state. 2852 V = V ^ RefVal::Released; 2853 V.clearCounts(); 2854 return state->set<RefBindings>(sym, V); 2855 case RefVal::NotOwned: 2856 V = V ^ RefVal::ErrorDeallocNotOwned; 2857 hasErr = V.getKind(); 2858 break; 2859 } 2860 break; 2861 2862 case NewAutoreleasePool: 2863 assert(!C.isObjCGCEnabled()); 2864 return state->add<AutoreleaseStack>(sym); 2865 2866 case MayEscape: 2867 if (V.getKind() == RefVal::Owned) { 2868 V = V ^ RefVal::NotOwned; 2869 break; 2870 } 2871 2872 // Fall-through. 2873 2874 case DoNothing: 2875 return state; 2876 2877 case Autorelease: 2878 if (C.isObjCGCEnabled()) 2879 return state; 2880 2881 // Update the autorelease counts. 2882 state = SendAutorelease(state, ARCountFactory, sym); 2883 V = V.autorelease(); 2884 break; 2885 2886 case StopTracking: 2887 return state->remove<RefBindings>(sym); 2888 2889 case IncRef: 2890 switch (V.getKind()) { 2891 default: 2892 llvm_unreachable("Invalid RefVal state for a retain."); 2893 case RefVal::Owned: 2894 case RefVal::NotOwned: 2895 V = V + 1; 2896 break; 2897 case RefVal::Released: 2898 // Non-GC cases are handled above. 2899 assert(C.isObjCGCEnabled()); 2900 V = (V ^ RefVal::Owned) + 1; 2901 break; 2902 } 2903 break; 2904 2905 case SelfOwn: 2906 V = V ^ RefVal::NotOwned; 2907 // Fall-through. 2908 case DecRef: 2909 case DecRefBridgedTransfered: 2910 switch (V.getKind()) { 2911 default: 2912 // case 'RefVal::Released' handled above. 2913 llvm_unreachable("Invalid RefVal state for a release."); 2914 2915 case RefVal::Owned: 2916 assert(V.getCount() > 0); 2917 if (V.getCount() == 1) 2918 V = V ^ (E == DecRefBridgedTransfered ? 2919 RefVal::NotOwned : RefVal::Released); 2920 V = V - 1; 2921 break; 2922 2923 case RefVal::NotOwned: 2924 if (V.getCount() > 0) 2925 V = V - 1; 2926 else { 2927 V = V ^ RefVal::ErrorReleaseNotOwned; 2928 hasErr = V.getKind(); 2929 } 2930 break; 2931 2932 case RefVal::Released: 2933 // Non-GC cases are handled above. 2934 assert(C.isObjCGCEnabled()); 2935 V = V ^ RefVal::ErrorUseAfterRelease; 2936 hasErr = V.getKind(); 2937 break; 2938 } 2939 break; 2940 } 2941 return state->set<RefBindings>(sym, V); 2942} 2943 2944void RetainCountChecker::processNonLeakError(ProgramStateRef St, 2945 SourceRange ErrorRange, 2946 RefVal::Kind ErrorKind, 2947 SymbolRef Sym, 2948 CheckerContext &C) const { 2949 ExplodedNode *N = C.generateSink(St); 2950 if (!N) 2951 return; 2952 2953 CFRefBug *BT; 2954 switch (ErrorKind) { 2955 default: 2956 llvm_unreachable("Unhandled error."); 2957 case RefVal::ErrorUseAfterRelease: 2958 if (!useAfterRelease) 2959 useAfterRelease.reset(new UseAfterRelease()); 2960 BT = &*useAfterRelease; 2961 break; 2962 case RefVal::ErrorReleaseNotOwned: 2963 if (!releaseNotOwned) 2964 releaseNotOwned.reset(new BadRelease()); 2965 BT = &*releaseNotOwned; 2966 break; 2967 case RefVal::ErrorDeallocGC: 2968 if (!deallocGC) 2969 deallocGC.reset(new DeallocGC()); 2970 BT = &*deallocGC; 2971 break; 2972 case RefVal::ErrorDeallocNotOwned: 2973 if (!deallocNotOwned) 2974 deallocNotOwned.reset(new DeallocNotOwned()); 2975 BT = &*deallocNotOwned; 2976 break; 2977 } 2978 2979 assert(BT); 2980 CFRefReport *report = new CFRefReport(*BT, C.getASTContext().getLangOptions(), 2981 C.isObjCGCEnabled(), SummaryLog, 2982 N, Sym); 2983 report->addRange(ErrorRange); 2984 C.EmitReport(report); 2985} 2986 2987//===----------------------------------------------------------------------===// 2988// Handle the return values of retain-count-related functions. 2989//===----------------------------------------------------------------------===// 2990 2991bool RetainCountChecker::evalCall(const CallExpr *CE, CheckerContext &C) const { 2992 // Get the callee. We're only interested in simple C functions. 2993 ProgramStateRef state = C.getState(); 2994 const FunctionDecl *FD = C.getCalleeDecl(CE); 2995 if (!FD) 2996 return false; 2997 2998 IdentifierInfo *II = FD->getIdentifier(); 2999 if (!II) 3000 return false; 3001 3002 // For now, we're only handling the functions that return aliases of their 3003 // arguments: CFRetain and CFMakeCollectable (and their families). 3004 // Eventually we should add other functions we can model entirely, 3005 // such as CFRelease, which don't invalidate their arguments or globals. 3006 if (CE->getNumArgs() != 1) 3007 return false; 3008 3009 // Get the name of the function. 3010 StringRef FName = II->getName(); 3011 FName = FName.substr(FName.find_first_not_of('_')); 3012 3013 // See if it's one of the specific functions we know how to eval. 3014 bool canEval = false; 3015 3016 QualType ResultTy = CE->getCallReturnType(); 3017 if (ResultTy->isObjCIdType()) { 3018 // Handle: id NSMakeCollectable(CFTypeRef) 3019 canEval = II->isStr("NSMakeCollectable"); 3020 } else if (ResultTy->isPointerType()) { 3021 // Handle: (CF|CG)Retain 3022 // CFMakeCollectable 3023 // It's okay to be a little sloppy here (CGMakeCollectable doesn't exist). 3024 if (cocoa::isRefType(ResultTy, "CF", FName) || 3025 cocoa::isRefType(ResultTy, "CG", FName)) { 3026 canEval = isRetain(FD, FName) || isMakeCollectable(FD, FName); 3027 } 3028 } 3029 3030 if (!canEval) 3031 return false; 3032 3033 // Bind the return value. 3034 const LocationContext *LCtx = C.getLocationContext(); 3035 SVal RetVal = state->getSVal(CE->getArg(0), LCtx); 3036 if (RetVal.isUnknown()) { 3037 // If the receiver is unknown, conjure a return value. 3038 SValBuilder &SVB = C.getSValBuilder(); 3039 unsigned Count = C.getCurrentBlockCount(); 3040 SVal RetVal = SVB.getConjuredSymbolVal(0, CE, ResultTy, Count); 3041 } 3042 state = state->BindExpr(CE, LCtx, RetVal, false); 3043 3044 // FIXME: This should not be necessary, but otherwise the argument seems to be 3045 // considered alive during the next statement. 3046 if (const MemRegion *ArgRegion = RetVal.getAsRegion()) { 3047 // Save the refcount status of the argument. 3048 SymbolRef Sym = RetVal.getAsLocSymbol(); 3049 RefBindings::data_type *Binding = 0; 3050 if (Sym) 3051 Binding = state->get<RefBindings>(Sym); 3052 3053 // Invalidate the argument region. 3054 unsigned Count = C.getCurrentBlockCount(); 3055 state = state->invalidateRegions(ArgRegion, CE, Count); 3056 3057 // Restore the refcount status of the argument. 3058 if (Binding) 3059 state = state->set<RefBindings>(Sym, *Binding); 3060 } 3061 3062 C.addTransition(state); 3063 return true; 3064} 3065 3066//===----------------------------------------------------------------------===// 3067// Handle return statements. 3068//===----------------------------------------------------------------------===// 3069 3070void RetainCountChecker::checkPreStmt(const ReturnStmt *S, 3071 CheckerContext &C) const { 3072 const Expr *RetE = S->getRetValue(); 3073 if (!RetE) 3074 return; 3075 3076 ProgramStateRef state = C.getState(); 3077 SymbolRef Sym = 3078 state->getSValAsScalarOrLoc(RetE, C.getLocationContext()).getAsLocSymbol(); 3079 if (!Sym) 3080 return; 3081 3082 // Get the reference count binding (if any). 3083 const RefVal *T = state->get<RefBindings>(Sym); 3084 if (!T) 3085 return; 3086 3087 // Change the reference count. 3088 RefVal X = *T; 3089 3090 switch (X.getKind()) { 3091 case RefVal::Owned: { 3092 unsigned cnt = X.getCount(); 3093 assert(cnt > 0); 3094 X.setCount(cnt - 1); 3095 X = X ^ RefVal::ReturnedOwned; 3096 break; 3097 } 3098 3099 case RefVal::NotOwned: { 3100 unsigned cnt = X.getCount(); 3101 if (cnt) { 3102 X.setCount(cnt - 1); 3103 X = X ^ RefVal::ReturnedOwned; 3104 } 3105 else { 3106 X = X ^ RefVal::ReturnedNotOwned; 3107 } 3108 break; 3109 } 3110 3111 default: 3112 return; 3113 } 3114 3115 // Update the binding. 3116 state = state->set<RefBindings>(Sym, X); 3117 ExplodedNode *Pred = C.addTransition(state); 3118 3119 // At this point we have updated the state properly. 3120 // Everything after this is merely checking to see if the return value has 3121 // been over- or under-retained. 3122 3123 // Did we cache out? 3124 if (!Pred) 3125 return; 3126 3127 // Update the autorelease counts. 3128 static SimpleProgramPointTag 3129 AutoreleaseTag("RetainCountChecker : Autorelease"); 3130 GenericNodeBuilderRefCount Bd(C, &AutoreleaseTag); 3131 llvm::tie(Pred, state) = handleAutoreleaseCounts(state, Bd, Pred, C, Sym, X); 3132 3133 // Did we cache out? 3134 if (!Pred) 3135 return; 3136 3137 // Get the updated binding. 3138 T = state->get<RefBindings>(Sym); 3139 assert(T); 3140 X = *T; 3141 3142 // Consult the summary of the enclosing method. 3143 RetainSummaryManager &Summaries = getSummaryManager(C); 3144 const Decl *CD = &Pred->getCodeDecl(); 3145 3146 if (const ObjCMethodDecl *MD = dyn_cast<ObjCMethodDecl>(CD)) { 3147 // Unlike regular functions, /all/ ObjC methods are assumed to always 3148 // follow Cocoa retain-count conventions, not just those with special 3149 // names or attributes. 3150 const RetainSummary *Summ = Summaries.getMethodSummary(MD); 3151 RetEffect RE = Summ ? Summ->getRetEffect() : RetEffect::MakeNoRet(); 3152 checkReturnWithRetEffect(S, C, Pred, RE, X, Sym, state); 3153 } 3154 3155 if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(CD)) { 3156 if (!isa<CXXMethodDecl>(FD)) 3157 if (const RetainSummary *Summ = Summaries.getSummary(FD)) 3158 checkReturnWithRetEffect(S, C, Pred, Summ->getRetEffect(), X, 3159 Sym, state); 3160 } 3161} 3162 3163void RetainCountChecker::checkReturnWithRetEffect(const ReturnStmt *S, 3164 CheckerContext &C, 3165 ExplodedNode *Pred, 3166 RetEffect RE, RefVal X, 3167 SymbolRef Sym, 3168 ProgramStateRef state) const { 3169 // Any leaks or other errors? 3170 if (X.isReturnedOwned() && X.getCount() == 0) { 3171 if (RE.getKind() != RetEffect::NoRet) { 3172 bool hasError = false; 3173 if (C.isObjCGCEnabled() && RE.getObjKind() == RetEffect::ObjC) { 3174 // Things are more complicated with garbage collection. If the 3175 // returned object is suppose to be an Objective-C object, we have 3176 // a leak (as the caller expects a GC'ed object) because no 3177 // method should return ownership unless it returns a CF object. 3178 hasError = true; 3179 X = X ^ RefVal::ErrorGCLeakReturned; 3180 } 3181 else if (!RE.isOwned()) { 3182 // Either we are using GC and the returned object is a CF type 3183 // or we aren't using GC. In either case, we expect that the 3184 // enclosing method is expected to return ownership. 3185 hasError = true; 3186 X = X ^ RefVal::ErrorLeakReturned; 3187 } 3188 3189 if (hasError) { 3190 // Generate an error node. 3191 state = state->set<RefBindings>(Sym, X); 3192 3193 static SimpleProgramPointTag 3194 ReturnOwnLeakTag("RetainCountChecker : ReturnsOwnLeak"); 3195 ExplodedNode *N = C.addTransition(state, Pred, &ReturnOwnLeakTag); 3196 if (N) { 3197 const LangOptions &LOpts = C.getASTContext().getLangOptions(); 3198 bool GCEnabled = C.isObjCGCEnabled(); 3199 CFRefReport *report = 3200 new CFRefLeakReport(*getLeakAtReturnBug(LOpts, GCEnabled), 3201 LOpts, GCEnabled, SummaryLog, 3202 N, Sym, C); 3203 C.EmitReport(report); 3204 } 3205 } 3206 } 3207 } else if (X.isReturnedNotOwned()) { 3208 if (RE.isOwned()) { 3209 // Trying to return a not owned object to a caller expecting an 3210 // owned object. 3211 state = state->set<RefBindings>(Sym, X ^ RefVal::ErrorReturnedNotOwned); 3212 3213 static SimpleProgramPointTag 3214 ReturnNotOwnedTag("RetainCountChecker : ReturnNotOwnedForOwned"); 3215 ExplodedNode *N = C.addTransition(state, Pred, &ReturnNotOwnedTag); 3216 if (N) { 3217 if (!returnNotOwnedForOwned) 3218 returnNotOwnedForOwned.reset(new ReturnedNotOwnedForOwned()); 3219 3220 CFRefReport *report = 3221 new CFRefReport(*returnNotOwnedForOwned, 3222 C.getASTContext().getLangOptions(), 3223 C.isObjCGCEnabled(), SummaryLog, N, Sym); 3224 C.EmitReport(report); 3225 } 3226 } 3227 } 3228} 3229 3230//===----------------------------------------------------------------------===// 3231// Check various ways a symbol can be invalidated. 3232//===----------------------------------------------------------------------===// 3233 3234void RetainCountChecker::checkBind(SVal loc, SVal val, const Stmt *S, 3235 CheckerContext &C) const { 3236 // Are we storing to something that causes the value to "escape"? 3237 bool escapes = true; 3238 3239 // A value escapes in three possible cases (this may change): 3240 // 3241 // (1) we are binding to something that is not a memory region. 3242 // (2) we are binding to a memregion that does not have stack storage 3243 // (3) we are binding to a memregion with stack storage that the store 3244 // does not understand. 3245 ProgramStateRef state = C.getState(); 3246 3247 if (loc::MemRegionVal *regionLoc = dyn_cast<loc::MemRegionVal>(&loc)) { 3248 escapes = !regionLoc->getRegion()->hasStackStorage(); 3249 3250 if (!escapes) { 3251 // To test (3), generate a new state with the binding added. If it is 3252 // the same state, then it escapes (since the store cannot represent 3253 // the binding). 3254 escapes = (state == (state->bindLoc(*regionLoc, val))); 3255 } 3256 } 3257 3258 // If our store can represent the binding and we aren't storing to something 3259 // that doesn't have local storage then just return and have the simulation 3260 // state continue as is. 3261 if (!escapes) 3262 return; 3263 3264 // Otherwise, find all symbols referenced by 'val' that we are tracking 3265 // and stop tracking them. 3266 state = state->scanReachableSymbols<StopTrackingCallback>(val).getState(); 3267 C.addTransition(state); 3268} 3269 3270ProgramStateRef RetainCountChecker::evalAssume(ProgramStateRef state, 3271 SVal Cond, 3272 bool Assumption) const { 3273 3274 // FIXME: We may add to the interface of evalAssume the list of symbols 3275 // whose assumptions have changed. For now we just iterate through the 3276 // bindings and check if any of the tracked symbols are NULL. This isn't 3277 // too bad since the number of symbols we will track in practice are 3278 // probably small and evalAssume is only called at branches and a few 3279 // other places. 3280 RefBindings B = state->get<RefBindings>(); 3281 3282 if (B.isEmpty()) 3283 return state; 3284 3285 bool changed = false; 3286 RefBindings::Factory &RefBFactory = state->get_context<RefBindings>(); 3287 3288 for (RefBindings::iterator I = B.begin(), E = B.end(); I != E; ++I) { 3289 // Check if the symbol is null (or equal to any constant). 3290 // If this is the case, stop tracking the symbol. 3291 if (state->getSymVal(I.getKey())) { 3292 changed = true; 3293 B = RefBFactory.remove(B, I.getKey()); 3294 } 3295 } 3296 3297 if (changed) 3298 state = state->set<RefBindings>(B); 3299 3300 return state; 3301} 3302 3303ProgramStateRef 3304RetainCountChecker::checkRegionChanges(ProgramStateRef state, 3305 const StoreManager::InvalidatedSymbols *invalidated, 3306 ArrayRef<const MemRegion *> ExplicitRegions, 3307 ArrayRef<const MemRegion *> Regions, 3308 const CallOrObjCMessage *Call) const { 3309 if (!invalidated) 3310 return state; 3311 3312 llvm::SmallPtrSet<SymbolRef, 8> WhitelistedSymbols; 3313 for (ArrayRef<const MemRegion *>::iterator I = ExplicitRegions.begin(), 3314 E = ExplicitRegions.end(); I != E; ++I) { 3315 if (const SymbolicRegion *SR = (*I)->StripCasts()->getAs<SymbolicRegion>()) 3316 WhitelistedSymbols.insert(SR->getSymbol()); 3317 } 3318 3319 for (StoreManager::InvalidatedSymbols::const_iterator I=invalidated->begin(), 3320 E = invalidated->end(); I!=E; ++I) { 3321 SymbolRef sym = *I; 3322 if (WhitelistedSymbols.count(sym)) 3323 continue; 3324 // Remove any existing reference-count binding. 3325 state = state->remove<RefBindings>(sym); 3326 } 3327 return state; 3328} 3329 3330//===----------------------------------------------------------------------===// 3331// Handle dead symbols and end-of-path. 3332//===----------------------------------------------------------------------===// 3333 3334std::pair<ExplodedNode *, ProgramStateRef > 3335RetainCountChecker::handleAutoreleaseCounts(ProgramStateRef state, 3336 GenericNodeBuilderRefCount Bd, 3337 ExplodedNode *Pred, 3338 CheckerContext &Ctx, 3339 SymbolRef Sym, RefVal V) const { 3340 unsigned ACnt = V.getAutoreleaseCount(); 3341 3342 // No autorelease counts? Nothing to be done. 3343 if (!ACnt) 3344 return std::make_pair(Pred, state); 3345 3346 assert(!Ctx.isObjCGCEnabled() && "Autorelease counts in GC mode?"); 3347 unsigned Cnt = V.getCount(); 3348 3349 // FIXME: Handle sending 'autorelease' to already released object. 3350 3351 if (V.getKind() == RefVal::ReturnedOwned) 3352 ++Cnt; 3353 3354 if (ACnt <= Cnt) { 3355 if (ACnt == Cnt) { 3356 V.clearCounts(); 3357 if (V.getKind() == RefVal::ReturnedOwned) 3358 V = V ^ RefVal::ReturnedNotOwned; 3359 else 3360 V = V ^ RefVal::NotOwned; 3361 } else { 3362 V.setCount(Cnt - ACnt); 3363 V.setAutoreleaseCount(0); 3364 } 3365 state = state->set<RefBindings>(Sym, V); 3366 ExplodedNode *N = Bd.MakeNode(state, Pred); 3367 if (N == 0) 3368 state = 0; 3369 return std::make_pair(N, state); 3370 } 3371 3372 // Woah! More autorelease counts then retain counts left. 3373 // Emit hard error. 3374 V = V ^ RefVal::ErrorOverAutorelease; 3375 state = state->set<RefBindings>(Sym, V); 3376 3377 if (ExplodedNode *N = Bd.MakeNode(state, Pred, true)) { 3378 SmallString<128> sbuf; 3379 llvm::raw_svector_ostream os(sbuf); 3380 os << "Object over-autoreleased: object was sent -autorelease "; 3381 if (V.getAutoreleaseCount() > 1) 3382 os << V.getAutoreleaseCount() << " times "; 3383 os << "but the object has a +" << V.getCount() << " retain count"; 3384 3385 if (!overAutorelease) 3386 overAutorelease.reset(new OverAutorelease()); 3387 3388 const LangOptions &LOpts = Ctx.getASTContext().getLangOptions(); 3389 CFRefReport *report = 3390 new CFRefReport(*overAutorelease, LOpts, /* GCEnabled = */ false, 3391 SummaryLog, N, Sym, os.str()); 3392 Ctx.EmitReport(report); 3393 } 3394 3395 return std::make_pair((ExplodedNode *)0, (ProgramStateRef )0); 3396} 3397 3398ProgramStateRef 3399RetainCountChecker::handleSymbolDeath(ProgramStateRef state, 3400 SymbolRef sid, RefVal V, 3401 SmallVectorImpl<SymbolRef> &Leaked) const { 3402 bool hasLeak = false; 3403 if (V.isOwned()) 3404 hasLeak = true; 3405 else if (V.isNotOwned() || V.isReturnedOwned()) 3406 hasLeak = (V.getCount() > 0); 3407 3408 if (!hasLeak) 3409 return state->remove<RefBindings>(sid); 3410 3411 Leaked.push_back(sid); 3412 return state->set<RefBindings>(sid, V ^ RefVal::ErrorLeak); 3413} 3414 3415ExplodedNode * 3416RetainCountChecker::processLeaks(ProgramStateRef state, 3417 SmallVectorImpl<SymbolRef> &Leaked, 3418 GenericNodeBuilderRefCount &Builder, 3419 CheckerContext &Ctx, 3420 ExplodedNode *Pred) const { 3421 if (Leaked.empty()) 3422 return Pred; 3423 3424 // Generate an intermediate node representing the leak point. 3425 ExplodedNode *N = Builder.MakeNode(state, Pred); 3426 3427 if (N) { 3428 for (SmallVectorImpl<SymbolRef>::iterator 3429 I = Leaked.begin(), E = Leaked.end(); I != E; ++I) { 3430 3431 const LangOptions &LOpts = Ctx.getASTContext().getLangOptions(); 3432 bool GCEnabled = Ctx.isObjCGCEnabled(); 3433 CFRefBug *BT = Pred ? getLeakWithinFunctionBug(LOpts, GCEnabled) 3434 : getLeakAtReturnBug(LOpts, GCEnabled); 3435 assert(BT && "BugType not initialized."); 3436 3437 CFRefLeakReport *report = new CFRefLeakReport(*BT, LOpts, GCEnabled, 3438 SummaryLog, N, *I, Ctx); 3439 Ctx.EmitReport(report); 3440 } 3441 } 3442 3443 return N; 3444} 3445 3446void RetainCountChecker::checkEndPath(CheckerContext &Ctx) const { 3447 ProgramStateRef state = Ctx.getState(); 3448 GenericNodeBuilderRefCount Bd(Ctx); 3449 RefBindings B = state->get<RefBindings>(); 3450 ExplodedNode *Pred = Ctx.getPredecessor(); 3451 3452 for (RefBindings::iterator I = B.begin(), E = B.end(); I != E; ++I) { 3453 llvm::tie(Pred, state) = handleAutoreleaseCounts(state, Bd, Pred, Ctx, 3454 I->first, I->second); 3455 if (!state) 3456 return; 3457 } 3458 3459 // If the current LocationContext has a parent, don't check for leaks. 3460 // We will do that later. 3461 // FIXME: we should instead check for imblances of the retain/releases, 3462 // and suggest annotations. 3463 if (Ctx.getLocationContext()->getParent()) 3464 return; 3465 3466 B = state->get<RefBindings>(); 3467 SmallVector<SymbolRef, 10> Leaked; 3468 3469 for (RefBindings::iterator I = B.begin(), E = B.end(); I != E; ++I) 3470 state = handleSymbolDeath(state, I->first, I->second, Leaked); 3471 3472 processLeaks(state, Leaked, Bd, Ctx, Pred); 3473} 3474 3475const ProgramPointTag * 3476RetainCountChecker::getDeadSymbolTag(SymbolRef sym) const { 3477 const SimpleProgramPointTag *&tag = DeadSymbolTags[sym]; 3478 if (!tag) { 3479 SmallString<64> buf; 3480 llvm::raw_svector_ostream out(buf); 3481 out << "RetainCountChecker : Dead Symbol : "; 3482 sym->dumpToStream(out); 3483 tag = new SimpleProgramPointTag(out.str()); 3484 } 3485 return tag; 3486} 3487 3488void RetainCountChecker::checkDeadSymbols(SymbolReaper &SymReaper, 3489 CheckerContext &C) const { 3490 ExplodedNode *Pred = C.getPredecessor(); 3491 3492 ProgramStateRef state = C.getState(); 3493 RefBindings B = state->get<RefBindings>(); 3494 3495 // Update counts from autorelease pools 3496 for (SymbolReaper::dead_iterator I = SymReaper.dead_begin(), 3497 E = SymReaper.dead_end(); I != E; ++I) { 3498 SymbolRef Sym = *I; 3499 if (const RefVal *T = B.lookup(Sym)){ 3500 // Use the symbol as the tag. 3501 // FIXME: This might not be as unique as we would like. 3502 GenericNodeBuilderRefCount Bd(C, getDeadSymbolTag(Sym)); 3503 llvm::tie(Pred, state) = handleAutoreleaseCounts(state, Bd, Pred, C, 3504 Sym, *T); 3505 if (!state) 3506 return; 3507 } 3508 } 3509 3510 B = state->get<RefBindings>(); 3511 SmallVector<SymbolRef, 10> Leaked; 3512 3513 for (SymbolReaper::dead_iterator I = SymReaper.dead_begin(), 3514 E = SymReaper.dead_end(); I != E; ++I) { 3515 if (const RefVal *T = B.lookup(*I)) 3516 state = handleSymbolDeath(state, *I, *T, Leaked); 3517 } 3518 3519 { 3520 GenericNodeBuilderRefCount Bd(C, this); 3521 Pred = processLeaks(state, Leaked, Bd, C, Pred); 3522 } 3523 3524 // Did we cache out? 3525 if (!Pred) 3526 return; 3527 3528 // Now generate a new node that nukes the old bindings. 3529 RefBindings::Factory &F = state->get_context<RefBindings>(); 3530 3531 for (SymbolReaper::dead_iterator I = SymReaper.dead_begin(), 3532 E = SymReaper.dead_end(); I != E; ++I) 3533 B = F.remove(B, *I); 3534 3535 state = state->set<RefBindings>(B); 3536 C.addTransition(state, Pred); 3537} 3538 3539//===----------------------------------------------------------------------===// 3540// Debug printing of refcount bindings and autorelease pools. 3541//===----------------------------------------------------------------------===// 3542 3543static void PrintPool(raw_ostream &Out, SymbolRef Sym, 3544 ProgramStateRef State) { 3545 Out << ' '; 3546 if (Sym) 3547 Sym->dumpToStream(Out); 3548 else 3549 Out << "<pool>"; 3550 Out << ":{"; 3551 3552 // Get the contents of the pool. 3553 if (const ARCounts *Cnts = State->get<AutoreleasePoolContents>(Sym)) 3554 for (ARCounts::iterator I = Cnts->begin(), E = Cnts->end(); I != E; ++I) 3555 Out << '(' << I.getKey() << ',' << I.getData() << ')'; 3556 3557 Out << '}'; 3558} 3559 3560static bool UsesAutorelease(ProgramStateRef state) { 3561 // A state uses autorelease if it allocated an autorelease pool or if it has 3562 // objects in the caller's autorelease pool. 3563 return !state->get<AutoreleaseStack>().isEmpty() || 3564 state->get<AutoreleasePoolContents>(SymbolRef()); 3565} 3566 3567void RetainCountChecker::printState(raw_ostream &Out, ProgramStateRef State, 3568 const char *NL, const char *Sep) const { 3569 3570 RefBindings B = State->get<RefBindings>(); 3571 3572 if (!B.isEmpty()) 3573 Out << Sep << NL; 3574 3575 for (RefBindings::iterator I = B.begin(), E = B.end(); I != E; ++I) { 3576 Out << I->first << " : "; 3577 I->second.print(Out); 3578 Out << NL; 3579 } 3580 3581 // Print the autorelease stack. 3582 if (UsesAutorelease(State)) { 3583 Out << Sep << NL << "AR pool stack:"; 3584 ARStack Stack = State->get<AutoreleaseStack>(); 3585 3586 PrintPool(Out, SymbolRef(), State); // Print the caller's pool. 3587 for (ARStack::iterator I = Stack.begin(), E = Stack.end(); I != E; ++I) 3588 PrintPool(Out, *I, State); 3589 3590 Out << NL; 3591 } 3592} 3593 3594//===----------------------------------------------------------------------===// 3595// Checker registration. 3596//===----------------------------------------------------------------------===// 3597 3598void ento::registerRetainCountChecker(CheckerManager &Mgr) { 3599 Mgr.registerChecker<RetainCountChecker>(); 3600} 3601 3602