RetainCountChecker.cpp revision e7e0168f625368032a5d2b4471d3406cd9d9f8ae
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* name, 659 const RetainSummary *Summ, bool isNullary = true) { 660 IdentifierInfo* ClsII = &Ctx.Idents.get(Cls); 661 Selector S = isNullary ? GetNullarySelector(name, Ctx) 662 : GetUnarySelector(name, Ctx); 663 ObjCClassMethodSummaries[ObjCSummaryKey(ClsII, S)] = Summ; 664 } 665 666 void addInstMethSummary(const char* Cls, const char* nullaryName, 667 const RetainSummary *Summ) { 668 IdentifierInfo* ClsII = &Ctx.Idents.get(Cls); 669 Selector S = GetNullarySelector(nullaryName, Ctx); 670 ObjCMethodSummaries[ObjCSummaryKey(ClsII, S)] = Summ; 671 } 672 673 Selector generateSelector(va_list argp) { 674 SmallVector<IdentifierInfo*, 10> II; 675 676 while (const char* s = va_arg(argp, const char*)) 677 II.push_back(&Ctx.Idents.get(s)); 678 679 return Ctx.Selectors.getSelector(II.size(), &II[0]); 680 } 681 682 void addMethodSummary(IdentifierInfo *ClsII, ObjCMethodSummariesTy& Summaries, 683 const RetainSummary * Summ, va_list argp) { 684 Selector S = generateSelector(argp); 685 Summaries[ObjCSummaryKey(ClsII, S)] = Summ; 686 } 687 688 void addInstMethSummary(const char* Cls, const RetainSummary * Summ, ...) { 689 va_list argp; 690 va_start(argp, Summ); 691 addMethodSummary(&Ctx.Idents.get(Cls), ObjCMethodSummaries, Summ, argp); 692 va_end(argp); 693 } 694 695 void addClsMethSummary(const char* Cls, const RetainSummary * Summ, ...) { 696 va_list argp; 697 va_start(argp, Summ); 698 addMethodSummary(&Ctx.Idents.get(Cls),ObjCClassMethodSummaries, Summ, argp); 699 va_end(argp); 700 } 701 702 void addClsMethSummary(IdentifierInfo *II, const RetainSummary * Summ, ...) { 703 va_list argp; 704 va_start(argp, Summ); 705 addMethodSummary(II, ObjCClassMethodSummaries, Summ, argp); 706 va_end(argp); 707 } 708 709public: 710 711 RetainSummaryManager(ASTContext &ctx, bool gcenabled, bool usesARC) 712 : Ctx(ctx), 713 GCEnabled(gcenabled), 714 ARCEnabled(usesARC), 715 AF(BPAlloc), ScratchArgs(AF.getEmptyMap()), 716 ObjCAllocRetE(gcenabled 717 ? RetEffect::MakeGCNotOwned() 718 : (usesARC ? RetEffect::MakeARCNotOwned() 719 : RetEffect::MakeOwned(RetEffect::ObjC, true))), 720 ObjCInitRetE(gcenabled 721 ? RetEffect::MakeGCNotOwned() 722 : (usesARC ? RetEffect::MakeARCNotOwned() 723 : RetEffect::MakeOwnedWhenTrackedReceiver())), 724 DefaultSummary(AF.getEmptyMap() /* per-argument effects (none) */, 725 RetEffect::MakeNoRet() /* return effect */, 726 MayEscape, /* default argument effect */ 727 DoNothing /* receiver effect */), 728 StopSummary(0) { 729 730 InitializeClassMethodSummaries(); 731 InitializeMethodSummaries(); 732 } 733 734 const RetainSummary *getSummary(const FunctionDecl *FD); 735 736 const RetainSummary *getInstanceMethodSummary(const ObjCMessage &msg, 737 ProgramStateRef state, 738 const LocationContext *LC); 739 740 const RetainSummary *getInstanceMethodSummary(const ObjCMessage &msg, 741 const ObjCInterfaceDecl *ID) { 742 return getInstanceMethodSummary(msg.getSelector(), 0, 743 ID, msg.getMethodDecl(), msg.getType(Ctx)); 744 } 745 746 const RetainSummary *getInstanceMethodSummary(Selector S, 747 IdentifierInfo *ClsName, 748 const ObjCInterfaceDecl *ID, 749 const ObjCMethodDecl *MD, 750 QualType RetTy); 751 752 const RetainSummary *getClassMethodSummary(Selector S, 753 IdentifierInfo *ClsName, 754 const ObjCInterfaceDecl *ID, 755 const ObjCMethodDecl *MD, 756 QualType RetTy); 757 758 const RetainSummary *getClassMethodSummary(const ObjCMessage &msg) { 759 const ObjCInterfaceDecl *Class = 0; 760 if (!msg.isInstanceMessage()) 761 Class = msg.getReceiverInterface(); 762 763 return getClassMethodSummary(msg.getSelector(), 764 Class? Class->getIdentifier() : 0, 765 Class, 766 msg.getMethodDecl(), msg.getType(Ctx)); 767 } 768 769 /// getMethodSummary - This version of getMethodSummary is used to query 770 /// the summary for the current method being analyzed. 771 const RetainSummary *getMethodSummary(const ObjCMethodDecl *MD) { 772 // FIXME: Eventually this should be unneeded. 773 const ObjCInterfaceDecl *ID = MD->getClassInterface(); 774 Selector S = MD->getSelector(); 775 IdentifierInfo *ClsName = ID->getIdentifier(); 776 QualType ResultTy = MD->getResultType(); 777 778 if (MD->isInstanceMethod()) 779 return getInstanceMethodSummary(S, ClsName, ID, MD, ResultTy); 780 else 781 return getClassMethodSummary(S, ClsName, ID, MD, ResultTy); 782 } 783 784 const RetainSummary *getCommonMethodSummary(const ObjCMethodDecl *MD, 785 Selector S, QualType RetTy); 786 787 void updateSummaryFromAnnotations(const RetainSummary *&Summ, 788 const ObjCMethodDecl *MD); 789 790 void updateSummaryFromAnnotations(const RetainSummary *&Summ, 791 const FunctionDecl *FD); 792 793 bool isGCEnabled() const { return GCEnabled; } 794 795 bool isARCEnabled() const { return ARCEnabled; } 796 797 bool isARCorGCEnabled() const { return GCEnabled || ARCEnabled; } 798 799 const RetainSummary *copySummary(const RetainSummary *OldSumm) { 800 RetainSummary *Summ = (RetainSummary *) BPAlloc.Allocate<RetainSummary>(); 801 new (Summ) RetainSummary(*OldSumm); 802 return Summ; 803 } 804}; 805 806// Used to avoid allocating long-term (BPAlloc'd) memory for default retain 807// summaries. If a function or method looks like it has a default summary, but 808// it has annotations, the annotations are added to the stack-based template 809// and then copied into managed memory. 810class RetainSummaryTemplate { 811 RetainSummaryManager &Manager; 812 const RetainSummary *&RealSummary; 813 const RetainSummary *BaseSummary; 814 RetainSummary ScratchSummary; 815 bool Accessed; 816public: 817 RetainSummaryTemplate(const RetainSummary *&real, const RetainSummary &base, 818 RetainSummaryManager &manager) 819 : Manager(manager), 820 RealSummary(real), 821 BaseSummary(&base), 822 ScratchSummary(base), 823 Accessed(false) {} 824 825 ~RetainSummaryTemplate() { 826 if (Accessed) 827 RealSummary = Manager.copySummary(&ScratchSummary); 828 else if (!RealSummary) 829 RealSummary = BaseSummary; 830 } 831 832 RetainSummary &operator*() { 833 Accessed = true; 834 return ScratchSummary; 835 } 836 837 RetainSummary *operator->() { 838 Accessed = true; 839 return &ScratchSummary; 840 } 841}; 842 843} // end anonymous namespace 844 845//===----------------------------------------------------------------------===// 846// Implementation of checker data structures. 847//===----------------------------------------------------------------------===// 848 849ArgEffects RetainSummaryManager::getArgEffects() { 850 ArgEffects AE = ScratchArgs; 851 ScratchArgs = AF.getEmptyMap(); 852 return AE; 853} 854 855const RetainSummary * 856RetainSummaryManager::getPersistentSummary(ArgEffects AE, RetEffect RetEff, 857 ArgEffect ReceiverEff, 858 ArgEffect DefaultEff) { 859 // Create the summary and return it. 860 RetainSummary *Summ = (RetainSummary *) BPAlloc.Allocate<RetainSummary>(); 861 new (Summ) RetainSummary(AE, RetEff, DefaultEff, ReceiverEff); 862 return Summ; 863} 864 865//===----------------------------------------------------------------------===// 866// Summary creation for functions (largely uses of Core Foundation). 867//===----------------------------------------------------------------------===// 868 869static bool isRetain(const FunctionDecl *FD, StringRef FName) { 870 return FName.endswith("Retain"); 871} 872 873static bool isRelease(const FunctionDecl *FD, StringRef FName) { 874 return FName.endswith("Release"); 875} 876 877static bool isMakeCollectable(const FunctionDecl *FD, StringRef FName) { 878 // FIXME: Remove FunctionDecl parameter. 879 // FIXME: Is it really okay if MakeCollectable isn't a suffix? 880 return FName.find("MakeCollectable") != StringRef::npos; 881} 882 883const RetainSummary * RetainSummaryManager::getSummary(const FunctionDecl *FD) { 884 // Look up a summary in our cache of FunctionDecls -> Summaries. 885 FuncSummariesTy::iterator I = FuncSummaries.find(FD); 886 if (I != FuncSummaries.end()) 887 return I->second; 888 889 // No summary? Generate one. 890 const RetainSummary *S = 0; 891 892 do { 893 // We generate "stop" summaries for implicitly defined functions. 894 if (FD->isImplicit()) { 895 S = getPersistentStopSummary(); 896 break; 897 } 898 // For C++ methods, generate an implicit "stop" summary as well. We 899 // can relax this once we have a clear policy for C++ methods and 900 // ownership attributes. 901 if (isa<CXXMethodDecl>(FD)) { 902 S = getPersistentStopSummary(); 903 break; 904 } 905 906 // [PR 3337] Use 'getAs<FunctionType>' to strip away any typedefs on the 907 // function's type. 908 const FunctionType* FT = FD->getType()->getAs<FunctionType>(); 909 const IdentifierInfo *II = FD->getIdentifier(); 910 if (!II) 911 break; 912 913 StringRef FName = II->getName(); 914 915 // Strip away preceding '_'. Doing this here will effect all the checks 916 // down below. 917 FName = FName.substr(FName.find_first_not_of('_')); 918 919 // Inspect the result type. 920 QualType RetTy = FT->getResultType(); 921 922 // FIXME: This should all be refactored into a chain of "summary lookup" 923 // filters. 924 assert(ScratchArgs.isEmpty()); 925 926 if (FName == "pthread_create") { 927 // Part of: <rdar://problem/7299394>. This will be addressed 928 // better with IPA. 929 S = getPersistentStopSummary(); 930 } else if (FName == "NSMakeCollectable") { 931 // Handle: id NSMakeCollectable(CFTypeRef) 932 S = (RetTy->isObjCIdType()) 933 ? getUnarySummary(FT, cfmakecollectable) 934 : getPersistentStopSummary(); 935 } else if (FName == "IOBSDNameMatching" || 936 FName == "IOServiceMatching" || 937 FName == "IOServiceNameMatching" || 938 FName == "IORegistryEntryIDMatching" || 939 FName == "IOOpenFirmwarePathMatching") { 940 // Part of <rdar://problem/6961230>. (IOKit) 941 // This should be addressed using a API table. 942 S = getPersistentSummary(RetEffect::MakeOwned(RetEffect::CF, true), 943 DoNothing, DoNothing); 944 } else if (FName == "IOServiceGetMatchingService" || 945 FName == "IOServiceGetMatchingServices") { 946 // FIXES: <rdar://problem/6326900> 947 // This should be addressed using a API table. This strcmp is also 948 // a little gross, but there is no need to super optimize here. 949 ScratchArgs = AF.add(ScratchArgs, 1, DecRef); 950 S = getPersistentSummary(RetEffect::MakeNoRet(), DoNothing, DoNothing); 951 } else if (FName == "IOServiceAddNotification" || 952 FName == "IOServiceAddMatchingNotification") { 953 // Part of <rdar://problem/6961230>. (IOKit) 954 // This should be addressed using a API table. 955 ScratchArgs = AF.add(ScratchArgs, 2, DecRef); 956 S = getPersistentSummary(RetEffect::MakeNoRet(), DoNothing, DoNothing); 957 } else if (FName == "CVPixelBufferCreateWithBytes") { 958 // FIXES: <rdar://problem/7283567> 959 // Eventually this can be improved by recognizing that the pixel 960 // buffer passed to CVPixelBufferCreateWithBytes is released via 961 // a callback and doing full IPA to make sure this is done correctly. 962 // FIXME: This function has an out parameter that returns an 963 // allocated object. 964 ScratchArgs = AF.add(ScratchArgs, 7, StopTracking); 965 S = getPersistentSummary(RetEffect::MakeNoRet(), DoNothing, DoNothing); 966 } else if (FName == "CGBitmapContextCreateWithData") { 967 // FIXES: <rdar://problem/7358899> 968 // Eventually this can be improved by recognizing that 'releaseInfo' 969 // passed to CGBitmapContextCreateWithData is released via 970 // a callback and doing full IPA to make sure this is done correctly. 971 ScratchArgs = AF.add(ScratchArgs, 8, StopTracking); 972 S = getPersistentSummary(RetEffect::MakeOwned(RetEffect::CF, true), 973 DoNothing, DoNothing); 974 } else if (FName == "CVPixelBufferCreateWithPlanarBytes") { 975 // FIXES: <rdar://problem/7283567> 976 // Eventually this can be improved by recognizing that the pixel 977 // buffer passed to CVPixelBufferCreateWithPlanarBytes is released 978 // via a callback and doing full IPA to make sure this is done 979 // correctly. 980 ScratchArgs = AF.add(ScratchArgs, 12, StopTracking); 981 S = getPersistentSummary(RetEffect::MakeNoRet(), DoNothing, DoNothing); 982 } 983 984 // Did we get a summary? 985 if (S) 986 break; 987 988 // Enable this code once the semantics of NSDeallocateObject are resolved 989 // for GC. <rdar://problem/6619988> 990#if 0 991 // Handle: NSDeallocateObject(id anObject); 992 // This method does allow 'nil' (although we don't check it now). 993 if (strcmp(FName, "NSDeallocateObject") == 0) { 994 return RetTy == Ctx.VoidTy 995 ? getPersistentSummary(RetEffect::MakeNoRet(), DoNothing, Dealloc) 996 : getPersistentStopSummary(); 997 } 998#endif 999 1000 if (RetTy->isPointerType()) { 1001 // For CoreFoundation ('CF') types. 1002 if (cocoa::isRefType(RetTy, "CF", FName)) { 1003 if (isRetain(FD, FName)) 1004 S = getUnarySummary(FT, cfretain); 1005 else if (isMakeCollectable(FD, FName)) 1006 S = getUnarySummary(FT, cfmakecollectable); 1007 else 1008 S = getCFCreateGetRuleSummary(FD); 1009 1010 break; 1011 } 1012 1013 // For CoreGraphics ('CG') types. 1014 if (cocoa::isRefType(RetTy, "CG", FName)) { 1015 if (isRetain(FD, FName)) 1016 S = getUnarySummary(FT, cfretain); 1017 else 1018 S = getCFCreateGetRuleSummary(FD); 1019 1020 break; 1021 } 1022 1023 // For the Disk Arbitration API (DiskArbitration/DADisk.h) 1024 if (cocoa::isRefType(RetTy, "DADisk") || 1025 cocoa::isRefType(RetTy, "DADissenter") || 1026 cocoa::isRefType(RetTy, "DASessionRef")) { 1027 S = getCFCreateGetRuleSummary(FD); 1028 break; 1029 } 1030 1031 break; 1032 } 1033 1034 // Check for release functions, the only kind of functions that we care 1035 // about that don't return a pointer type. 1036 if (FName[0] == 'C' && (FName[1] == 'F' || FName[1] == 'G')) { 1037 // Test for 'CGCF'. 1038 FName = FName.substr(FName.startswith("CGCF") ? 4 : 2); 1039 1040 if (isRelease(FD, FName)) 1041 S = getUnarySummary(FT, cfrelease); 1042 else { 1043 assert (ScratchArgs.isEmpty()); 1044 // Remaining CoreFoundation and CoreGraphics functions. 1045 // We use to assume that they all strictly followed the ownership idiom 1046 // and that ownership cannot be transferred. While this is technically 1047 // correct, many methods allow a tracked object to escape. For example: 1048 // 1049 // CFMutableDictionaryRef x = CFDictionaryCreateMutable(...); 1050 // CFDictionaryAddValue(y, key, x); 1051 // CFRelease(x); 1052 // ... it is okay to use 'x' since 'y' has a reference to it 1053 // 1054 // We handle this and similar cases with the follow heuristic. If the 1055 // function name contains "InsertValue", "SetValue", "AddValue", 1056 // "AppendValue", or "SetAttribute", then we assume that arguments may 1057 // "escape." This means that something else holds on to the object, 1058 // allowing it be used even after its local retain count drops to 0. 1059 ArgEffect E = (StrInStrNoCase(FName, "InsertValue") != StringRef::npos|| 1060 StrInStrNoCase(FName, "AddValue") != StringRef::npos || 1061 StrInStrNoCase(FName, "SetValue") != StringRef::npos || 1062 StrInStrNoCase(FName, "AppendValue") != StringRef::npos|| 1063 StrInStrNoCase(FName, "SetAttribute") != StringRef::npos) 1064 ? MayEscape : DoNothing; 1065 1066 S = getPersistentSummary(RetEffect::MakeNoRet(), DoNothing, E); 1067 } 1068 } 1069 } 1070 while (0); 1071 1072 // Annotations override defaults. 1073 updateSummaryFromAnnotations(S, FD); 1074 1075 FuncSummaries[FD] = S; 1076 return S; 1077} 1078 1079const RetainSummary * 1080RetainSummaryManager::getCFCreateGetRuleSummary(const FunctionDecl *FD) { 1081 if (coreFoundation::followsCreateRule(FD)) 1082 return getCFSummaryCreateRule(FD); 1083 1084 return getCFSummaryGetRule(FD); 1085} 1086 1087const RetainSummary * 1088RetainSummaryManager::getUnarySummary(const FunctionType* FT, 1089 UnaryFuncKind func) { 1090 1091 // Sanity check that this is *really* a unary function. This can 1092 // happen if people do weird things. 1093 const FunctionProtoType* FTP = dyn_cast<FunctionProtoType>(FT); 1094 if (!FTP || FTP->getNumArgs() != 1) 1095 return getPersistentStopSummary(); 1096 1097 assert (ScratchArgs.isEmpty()); 1098 1099 ArgEffect Effect; 1100 switch (func) { 1101 case cfretain: Effect = IncRef; break; 1102 case cfrelease: Effect = DecRef; break; 1103 case cfmakecollectable: Effect = MakeCollectable; break; 1104 } 1105 1106 ScratchArgs = AF.add(ScratchArgs, 0, Effect); 1107 return getPersistentSummary(RetEffect::MakeNoRet(), DoNothing, DoNothing); 1108} 1109 1110const RetainSummary * 1111RetainSummaryManager::getCFSummaryCreateRule(const FunctionDecl *FD) { 1112 assert (ScratchArgs.isEmpty()); 1113 1114 return getPersistentSummary(RetEffect::MakeOwned(RetEffect::CF, true)); 1115} 1116 1117const RetainSummary * 1118RetainSummaryManager::getCFSummaryGetRule(const FunctionDecl *FD) { 1119 assert (ScratchArgs.isEmpty()); 1120 return getPersistentSummary(RetEffect::MakeNotOwned(RetEffect::CF), 1121 DoNothing, DoNothing); 1122} 1123 1124//===----------------------------------------------------------------------===// 1125// Summary creation for Selectors. 1126//===----------------------------------------------------------------------===// 1127 1128const RetainSummary * 1129RetainSummaryManager::getInitMethodSummary(QualType RetTy) { 1130 assert(ScratchArgs.isEmpty()); 1131 // 'init' methods conceptually return a newly allocated object and claim 1132 // the receiver. 1133 if (cocoa::isCocoaObjectRef(RetTy) || 1134 coreFoundation::isCFObjectRef(RetTy)) 1135 return getPersistentSummary(ObjCInitRetE, DecRefMsg); 1136 1137 return getDefaultSummary(); 1138} 1139 1140void 1141RetainSummaryManager::updateSummaryFromAnnotations(const RetainSummary *&Summ, 1142 const FunctionDecl *FD) { 1143 if (!FD) 1144 return; 1145 1146 RetainSummaryTemplate Template(Summ, DefaultSummary, *this); 1147 1148 // Effects on the parameters. 1149 unsigned parm_idx = 0; 1150 for (FunctionDecl::param_const_iterator pi = FD->param_begin(), 1151 pe = FD->param_end(); pi != pe; ++pi, ++parm_idx) { 1152 const ParmVarDecl *pd = *pi; 1153 if (pd->getAttr<NSConsumedAttr>()) { 1154 if (!GCEnabled) { 1155 Template->addArg(AF, parm_idx, DecRef); 1156 } 1157 } else if (pd->getAttr<CFConsumedAttr>()) { 1158 Template->addArg(AF, parm_idx, DecRef); 1159 } 1160 } 1161 1162 QualType RetTy = FD->getResultType(); 1163 1164 // Determine if there is a special return effect for this method. 1165 if (cocoa::isCocoaObjectRef(RetTy)) { 1166 if (FD->getAttr<NSReturnsRetainedAttr>()) { 1167 Template->setRetEffect(ObjCAllocRetE); 1168 } 1169 else if (FD->getAttr<CFReturnsRetainedAttr>()) { 1170 Template->setRetEffect(RetEffect::MakeOwned(RetEffect::CF, true)); 1171 } 1172 else if (FD->getAttr<NSReturnsNotRetainedAttr>()) { 1173 Template->setRetEffect(RetEffect::MakeNotOwned(RetEffect::ObjC)); 1174 } 1175 else if (FD->getAttr<CFReturnsNotRetainedAttr>()) { 1176 Template->setRetEffect(RetEffect::MakeNotOwned(RetEffect::CF)); 1177 } 1178 } else if (RetTy->getAs<PointerType>()) { 1179 if (FD->getAttr<CFReturnsRetainedAttr>()) { 1180 Template->setRetEffect(RetEffect::MakeOwned(RetEffect::CF, true)); 1181 } 1182 else if (FD->getAttr<CFReturnsNotRetainedAttr>()) { 1183 Template->setRetEffect(RetEffect::MakeNotOwned(RetEffect::CF)); 1184 } 1185 } 1186} 1187 1188void 1189RetainSummaryManager::updateSummaryFromAnnotations(const RetainSummary *&Summ, 1190 const ObjCMethodDecl *MD) { 1191 if (!MD) 1192 return; 1193 1194 RetainSummaryTemplate Template(Summ, DefaultSummary, *this); 1195 1196 bool isTrackedLoc = false; 1197 1198 // Effects on the receiver. 1199 if (MD->getAttr<NSConsumesSelfAttr>()) { 1200 if (!GCEnabled) 1201 Template->setReceiverEffect(DecRefMsg); 1202 } 1203 1204 // Effects on the parameters. 1205 unsigned parm_idx = 0; 1206 for (ObjCMethodDecl::param_const_iterator 1207 pi=MD->param_begin(), pe=MD->param_end(); 1208 pi != pe; ++pi, ++parm_idx) { 1209 const ParmVarDecl *pd = *pi; 1210 if (pd->getAttr<NSConsumedAttr>()) { 1211 if (!GCEnabled) 1212 Template->addArg(AF, parm_idx, DecRef); 1213 } 1214 else if(pd->getAttr<CFConsumedAttr>()) { 1215 Template->addArg(AF, parm_idx, DecRef); 1216 } 1217 } 1218 1219 // Determine if there is a special return effect for this method. 1220 if (cocoa::isCocoaObjectRef(MD->getResultType())) { 1221 if (MD->getAttr<NSReturnsRetainedAttr>()) { 1222 Template->setRetEffect(ObjCAllocRetE); 1223 return; 1224 } 1225 if (MD->getAttr<NSReturnsNotRetainedAttr>()) { 1226 Template->setRetEffect(RetEffect::MakeNotOwned(RetEffect::ObjC)); 1227 return; 1228 } 1229 1230 isTrackedLoc = true; 1231 } else { 1232 isTrackedLoc = MD->getResultType()->getAs<PointerType>() != NULL; 1233 } 1234 1235 if (isTrackedLoc) { 1236 if (MD->getAttr<CFReturnsRetainedAttr>()) 1237 Template->setRetEffect(RetEffect::MakeOwned(RetEffect::CF, true)); 1238 else if (MD->getAttr<CFReturnsNotRetainedAttr>()) 1239 Template->setRetEffect(RetEffect::MakeNotOwned(RetEffect::CF)); 1240 } 1241} 1242 1243const RetainSummary * 1244RetainSummaryManager::getCommonMethodSummary(const ObjCMethodDecl *MD, 1245 Selector S, QualType RetTy) { 1246 1247 if (MD) { 1248 // Scan the method decl for 'void*' arguments. These should be treated 1249 // as 'StopTracking' because they are often used with delegates. 1250 // Delegates are a frequent form of false positives with the retain 1251 // count checker. 1252 unsigned i = 0; 1253 for (ObjCMethodDecl::param_const_iterator I = MD->param_begin(), 1254 E = MD->param_end(); I != E; ++I, ++i) 1255 if (const ParmVarDecl *PD = *I) { 1256 QualType Ty = Ctx.getCanonicalType(PD->getType()); 1257 if (Ty.getLocalUnqualifiedType() == Ctx.VoidPtrTy) 1258 ScratchArgs = AF.add(ScratchArgs, i, StopTracking); 1259 } 1260 } 1261 1262 // Any special effect for the receiver? 1263 ArgEffect ReceiverEff = DoNothing; 1264 1265 // If one of the arguments in the selector has the keyword 'delegate' we 1266 // should stop tracking the reference count for the receiver. This is 1267 // because the reference count is quite possibly handled by a delegate 1268 // method. 1269 if (S.isKeywordSelector()) { 1270 const std::string &str = S.getAsString(); 1271 assert(!str.empty()); 1272 if (StrInStrNoCase(str, "delegate:") != StringRef::npos) 1273 ReceiverEff = StopTracking; 1274 } 1275 1276 // Look for methods that return an owned object. 1277 if (cocoa::isCocoaObjectRef(RetTy)) { 1278 // EXPERIMENTAL: assume the Cocoa conventions for all objects returned 1279 // by instance methods. 1280 RetEffect E = cocoa::followsFundamentalRule(S, MD) 1281 ? ObjCAllocRetE : RetEffect::MakeNotOwned(RetEffect::ObjC); 1282 1283 return getPersistentSummary(E, ReceiverEff, MayEscape); 1284 } 1285 1286 // Look for methods that return an owned core foundation object. 1287 if (coreFoundation::isCFObjectRef(RetTy)) { 1288 RetEffect E = cocoa::followsFundamentalRule(S, MD) 1289 ? RetEffect::MakeOwned(RetEffect::CF, true) 1290 : RetEffect::MakeNotOwned(RetEffect::CF); 1291 1292 return getPersistentSummary(E, ReceiverEff, MayEscape); 1293 } 1294 1295 if (ScratchArgs.isEmpty() && ReceiverEff == DoNothing) 1296 return getDefaultSummary(); 1297 1298 return getPersistentSummary(RetEffect::MakeNoRet(), ReceiverEff, MayEscape); 1299} 1300 1301const RetainSummary * 1302RetainSummaryManager::getInstanceMethodSummary(const ObjCMessage &msg, 1303 ProgramStateRef state, 1304 const LocationContext *LC) { 1305 1306 // We need the type-information of the tracked receiver object 1307 // Retrieve it from the state. 1308 const Expr *Receiver = msg.getInstanceReceiver(); 1309 const ObjCInterfaceDecl *ID = 0; 1310 1311 // FIXME: Is this really working as expected? There are cases where 1312 // we just use the 'ID' from the message expression. 1313 SVal receiverV; 1314 1315 if (Receiver) { 1316 receiverV = state->getSValAsScalarOrLoc(Receiver, LC); 1317 1318 // FIXME: Eventually replace the use of state->get<RefBindings> with 1319 // a generic API for reasoning about the Objective-C types of symbolic 1320 // objects. 1321 if (SymbolRef Sym = receiverV.getAsLocSymbol()) 1322 if (const RefVal *T = state->get<RefBindings>(Sym)) 1323 if (const ObjCObjectPointerType* PT = 1324 T->getType()->getAs<ObjCObjectPointerType>()) 1325 ID = PT->getInterfaceDecl(); 1326 1327 // FIXME: this is a hack. This may or may not be the actual method 1328 // that is called. 1329 if (!ID) { 1330 if (const ObjCObjectPointerType *PT = 1331 Receiver->getType()->getAs<ObjCObjectPointerType>()) 1332 ID = PT->getInterfaceDecl(); 1333 } 1334 } else { 1335 // FIXME: Hack for 'super'. 1336 ID = msg.getReceiverInterface(); 1337 } 1338 1339 // FIXME: The receiver could be a reference to a class, meaning that 1340 // we should use the class method. 1341 return getInstanceMethodSummary(msg, ID); 1342} 1343 1344const RetainSummary * 1345RetainSummaryManager::getInstanceMethodSummary(Selector S, 1346 IdentifierInfo *ClsName, 1347 const ObjCInterfaceDecl *ID, 1348 const ObjCMethodDecl *MD, 1349 QualType RetTy) { 1350 1351 // Look up a summary in our summary cache. 1352 const RetainSummary *Summ = ObjCMethodSummaries.find(ID, ClsName, S); 1353 1354 if (!Summ) { 1355 assert(ScratchArgs.isEmpty()); 1356 1357 // "initXXX": pass-through for receiver. 1358 if (cocoa::deriveNamingConvention(S, MD) == cocoa::InitRule) 1359 Summ = getInitMethodSummary(RetTy); 1360 else 1361 Summ = getCommonMethodSummary(MD, S, RetTy); 1362 1363 // Annotations override defaults. 1364 updateSummaryFromAnnotations(Summ, MD); 1365 1366 // Memoize the summary. 1367 ObjCMethodSummaries[ObjCSummaryKey(ID, ClsName, S)] = Summ; 1368 } 1369 1370 return Summ; 1371} 1372 1373const RetainSummary * 1374RetainSummaryManager::getClassMethodSummary(Selector S, IdentifierInfo *ClsName, 1375 const ObjCInterfaceDecl *ID, 1376 const ObjCMethodDecl *MD, 1377 QualType RetTy) { 1378 1379 assert(ClsName && "Class name must be specified."); 1380 const RetainSummary *Summ = ObjCClassMethodSummaries.find(ID, ClsName, S); 1381 1382 if (!Summ) { 1383 Summ = getCommonMethodSummary(MD, S, RetTy); 1384 1385 // Annotations override defaults. 1386 updateSummaryFromAnnotations(Summ, MD); 1387 1388 // Memoize the summary. 1389 ObjCClassMethodSummaries[ObjCSummaryKey(ID, ClsName, S)] = Summ; 1390 } 1391 1392 return Summ; 1393} 1394 1395void RetainSummaryManager::InitializeClassMethodSummaries() { 1396 assert(ScratchArgs.isEmpty()); 1397 // Create the [NSAssertionHandler currentHander] summary. 1398 addClassMethSummary("NSAssertionHandler", "currentHandler", 1399 getPersistentSummary(RetEffect::MakeNotOwned(RetEffect::ObjC))); 1400 1401 // Create the [NSAutoreleasePool addObject:] summary. 1402 ScratchArgs = AF.add(ScratchArgs, 0, Autorelease); 1403 addClassMethSummary("NSAutoreleasePool", "addObject", 1404 getPersistentSummary(RetEffect::MakeNoRet(), 1405 DoNothing, Autorelease)); 1406 1407 // Create the summaries for [NSObject performSelector...]. We treat 1408 // these as 'stop tracking' for the arguments because they are often 1409 // used for delegates that can release the object. When we have better 1410 // inter-procedural analysis we can potentially do something better. This 1411 // workaround is to remove false positives. 1412 const RetainSummary *Summ = 1413 getPersistentSummary(RetEffect::MakeNoRet(), DoNothing, StopTracking); 1414 IdentifierInfo *NSObjectII = &Ctx.Idents.get("NSObject"); 1415 addClsMethSummary(NSObjectII, Summ, "performSelector", "withObject", 1416 "afterDelay", NULL); 1417 addClsMethSummary(NSObjectII, Summ, "performSelector", "withObject", 1418 "afterDelay", "inModes", NULL); 1419 addClsMethSummary(NSObjectII, Summ, "performSelectorOnMainThread", 1420 "withObject", "waitUntilDone", NULL); 1421 addClsMethSummary(NSObjectII, Summ, "performSelectorOnMainThread", 1422 "withObject", "waitUntilDone", "modes", NULL); 1423 addClsMethSummary(NSObjectII, Summ, "performSelector", "onThread", 1424 "withObject", "waitUntilDone", NULL); 1425 addClsMethSummary(NSObjectII, Summ, "performSelector", "onThread", 1426 "withObject", "waitUntilDone", "modes", NULL); 1427 addClsMethSummary(NSObjectII, Summ, "performSelectorInBackground", 1428 "withObject", NULL); 1429} 1430 1431void RetainSummaryManager::InitializeMethodSummaries() { 1432 1433 assert (ScratchArgs.isEmpty()); 1434 1435 // Create the "init" selector. It just acts as a pass-through for the 1436 // receiver. 1437 const RetainSummary *InitSumm = getPersistentSummary(ObjCInitRetE, DecRefMsg); 1438 addNSObjectMethSummary(GetNullarySelector("init", Ctx), InitSumm); 1439 1440 // awakeAfterUsingCoder: behaves basically like an 'init' method. It 1441 // claims the receiver and returns a retained object. 1442 addNSObjectMethSummary(GetUnarySelector("awakeAfterUsingCoder", Ctx), 1443 InitSumm); 1444 1445 // The next methods are allocators. 1446 const RetainSummary *AllocSumm = getPersistentSummary(ObjCAllocRetE); 1447 const RetainSummary *CFAllocSumm = 1448 getPersistentSummary(RetEffect::MakeOwned(RetEffect::CF, true)); 1449 1450 // Create the "retain" selector. 1451 RetEffect NoRet = RetEffect::MakeNoRet(); 1452 const RetainSummary *Summ = getPersistentSummary(NoRet, IncRefMsg); 1453 addNSObjectMethSummary(GetNullarySelector("retain", Ctx), Summ); 1454 1455 // Create the "release" selector. 1456 Summ = getPersistentSummary(NoRet, DecRefMsg); 1457 addNSObjectMethSummary(GetNullarySelector("release", Ctx), Summ); 1458 1459 // Create the "drain" selector. 1460 Summ = getPersistentSummary(NoRet, isGCEnabled() ? DoNothing : DecRef); 1461 addNSObjectMethSummary(GetNullarySelector("drain", Ctx), Summ); 1462 1463 // Create the -dealloc summary. 1464 Summ = getPersistentSummary(NoRet, Dealloc); 1465 addNSObjectMethSummary(GetNullarySelector("dealloc", Ctx), Summ); 1466 1467 // Create the "autorelease" selector. 1468 Summ = getPersistentSummary(NoRet, Autorelease); 1469 addNSObjectMethSummary(GetNullarySelector("autorelease", Ctx), Summ); 1470 1471 // Specially handle NSAutoreleasePool. 1472 addInstMethSummary("NSAutoreleasePool", "init", 1473 getPersistentSummary(NoRet, NewAutoreleasePool)); 1474 1475 // For NSWindow, allocated objects are (initially) self-owned. 1476 // FIXME: For now we opt for false negatives with NSWindow, as these objects 1477 // self-own themselves. However, they only do this once they are displayed. 1478 // Thus, we need to track an NSWindow's display status. 1479 // This is tracked in <rdar://problem/6062711>. 1480 // See also http://llvm.org/bugs/show_bug.cgi?id=3714. 1481 const RetainSummary *NoTrackYet = getPersistentSummary(RetEffect::MakeNoRet(), 1482 StopTracking, 1483 StopTracking); 1484 1485 addClassMethSummary("NSWindow", "alloc", NoTrackYet); 1486 1487#if 0 1488 addInstMethSummary("NSWindow", NoTrackYet, "initWithContentRect", 1489 "styleMask", "backing", "defer", NULL); 1490 1491 addInstMethSummary("NSWindow", NoTrackYet, "initWithContentRect", 1492 "styleMask", "backing", "defer", "screen", NULL); 1493#endif 1494 1495 // For NSPanel (which subclasses NSWindow), allocated objects are not 1496 // self-owned. 1497 // FIXME: For now we don't track NSPanels. object for the same reason 1498 // as for NSWindow objects. 1499 addClassMethSummary("NSPanel", "alloc", NoTrackYet); 1500 1501#if 0 1502 addInstMethSummary("NSPanel", NoTrackYet, "initWithContentRect", 1503 "styleMask", "backing", "defer", NULL); 1504 1505 addInstMethSummary("NSPanel", NoTrackYet, "initWithContentRect", 1506 "styleMask", "backing", "defer", "screen", NULL); 1507#endif 1508 1509 // Don't track allocated autorelease pools yet, as it is okay to prematurely 1510 // exit a method. 1511 addClassMethSummary("NSAutoreleasePool", "alloc", NoTrackYet); 1512 addClassMethSummary("NSAutoreleasePool", "allocWithZone", NoTrackYet, false); 1513 1514 // Create summaries QCRenderer/QCView -createSnapShotImageOfType: 1515 addInstMethSummary("QCRenderer", AllocSumm, 1516 "createSnapshotImageOfType", NULL); 1517 addInstMethSummary("QCView", AllocSumm, 1518 "createSnapshotImageOfType", NULL); 1519 1520 // Create summaries for CIContext, 'createCGImage' and 1521 // 'createCGLayerWithSize'. These objects are CF objects, and are not 1522 // automatically garbage collected. 1523 addInstMethSummary("CIContext", CFAllocSumm, 1524 "createCGImage", "fromRect", NULL); 1525 addInstMethSummary("CIContext", CFAllocSumm, 1526 "createCGImage", "fromRect", "format", "colorSpace", NULL); 1527 addInstMethSummary("CIContext", CFAllocSumm, "createCGLayerWithSize", 1528 "info", NULL); 1529} 1530 1531//===----------------------------------------------------------------------===// 1532// AutoreleaseBindings - State used to track objects in autorelease pools. 1533//===----------------------------------------------------------------------===// 1534 1535typedef llvm::ImmutableMap<SymbolRef, unsigned> ARCounts; 1536typedef llvm::ImmutableMap<SymbolRef, ARCounts> ARPoolContents; 1537typedef llvm::ImmutableList<SymbolRef> ARStack; 1538 1539static int AutoRCIndex = 0; 1540static int AutoRBIndex = 0; 1541 1542namespace { class AutoreleasePoolContents {}; } 1543namespace { class AutoreleaseStack {}; } 1544 1545namespace clang { 1546namespace ento { 1547template<> struct ProgramStateTrait<AutoreleaseStack> 1548 : public ProgramStatePartialTrait<ARStack> { 1549 static inline void *GDMIndex() { return &AutoRBIndex; } 1550}; 1551 1552template<> struct ProgramStateTrait<AutoreleasePoolContents> 1553 : public ProgramStatePartialTrait<ARPoolContents> { 1554 static inline void *GDMIndex() { return &AutoRCIndex; } 1555}; 1556} // end GR namespace 1557} // end clang namespace 1558 1559static SymbolRef GetCurrentAutoreleasePool(ProgramStateRef state) { 1560 ARStack stack = state->get<AutoreleaseStack>(); 1561 return stack.isEmpty() ? SymbolRef() : stack.getHead(); 1562} 1563 1564static ProgramStateRef 1565SendAutorelease(ProgramStateRef state, 1566 ARCounts::Factory &F, 1567 SymbolRef sym) { 1568 SymbolRef pool = GetCurrentAutoreleasePool(state); 1569 const ARCounts *cnts = state->get<AutoreleasePoolContents>(pool); 1570 ARCounts newCnts(0); 1571 1572 if (cnts) { 1573 const unsigned *cnt = (*cnts).lookup(sym); 1574 newCnts = F.add(*cnts, sym, cnt ? *cnt + 1 : 1); 1575 } 1576 else 1577 newCnts = F.add(F.getEmptyMap(), sym, 1); 1578 1579 return state->set<AutoreleasePoolContents>(pool, newCnts); 1580} 1581 1582//===----------------------------------------------------------------------===// 1583// Error reporting. 1584//===----------------------------------------------------------------------===// 1585namespace { 1586 typedef llvm::DenseMap<const ExplodedNode *, const RetainSummary *> 1587 SummaryLogTy; 1588 1589 //===-------------===// 1590 // Bug Descriptions. // 1591 //===-------------===// 1592 1593 class CFRefBug : public BugType { 1594 protected: 1595 CFRefBug(StringRef name) 1596 : BugType(name, "Memory (Core Foundation/Objective-C)") {} 1597 public: 1598 1599 // FIXME: Eventually remove. 1600 virtual const char *getDescription() const = 0; 1601 1602 virtual bool isLeak() const { return false; } 1603 }; 1604 1605 class UseAfterRelease : public CFRefBug { 1606 public: 1607 UseAfterRelease() : CFRefBug("Use-after-release") {} 1608 1609 const char *getDescription() const { 1610 return "Reference-counted object is used after it is released"; 1611 } 1612 }; 1613 1614 class BadRelease : public CFRefBug { 1615 public: 1616 BadRelease() : CFRefBug("Bad release") {} 1617 1618 const char *getDescription() const { 1619 return "Incorrect decrement of the reference count of an object that is " 1620 "not owned at this point by the caller"; 1621 } 1622 }; 1623 1624 class DeallocGC : public CFRefBug { 1625 public: 1626 DeallocGC() 1627 : CFRefBug("-dealloc called while using garbage collection") {} 1628 1629 const char *getDescription() const { 1630 return "-dealloc called while using garbage collection"; 1631 } 1632 }; 1633 1634 class DeallocNotOwned : public CFRefBug { 1635 public: 1636 DeallocNotOwned() 1637 : CFRefBug("-dealloc sent to non-exclusively owned object") {} 1638 1639 const char *getDescription() const { 1640 return "-dealloc sent to object that may be referenced elsewhere"; 1641 } 1642 }; 1643 1644 class OverAutorelease : public CFRefBug { 1645 public: 1646 OverAutorelease() 1647 : CFRefBug("Object sent -autorelease too many times") {} 1648 1649 const char *getDescription() const { 1650 return "Object sent -autorelease too many times"; 1651 } 1652 }; 1653 1654 class ReturnedNotOwnedForOwned : public CFRefBug { 1655 public: 1656 ReturnedNotOwnedForOwned() 1657 : CFRefBug("Method should return an owned object") {} 1658 1659 const char *getDescription() const { 1660 return "Object with a +0 retain count returned to caller where a +1 " 1661 "(owning) retain count is expected"; 1662 } 1663 }; 1664 1665 class Leak : public CFRefBug { 1666 const bool isReturn; 1667 protected: 1668 Leak(StringRef name, bool isRet) 1669 : CFRefBug(name), isReturn(isRet) { 1670 // Leaks should not be reported if they are post-dominated by a sink. 1671 setSuppressOnSink(true); 1672 } 1673 public: 1674 1675 const char *getDescription() const { return ""; } 1676 1677 bool isLeak() const { return true; } 1678 }; 1679 1680 class LeakAtReturn : public Leak { 1681 public: 1682 LeakAtReturn(StringRef name) 1683 : Leak(name, true) {} 1684 }; 1685 1686 class LeakWithinFunction : public Leak { 1687 public: 1688 LeakWithinFunction(StringRef name) 1689 : Leak(name, false) {} 1690 }; 1691 1692 //===---------===// 1693 // Bug Reports. // 1694 //===---------===// 1695 1696 class CFRefReportVisitor : public BugReporterVisitor { 1697 protected: 1698 SymbolRef Sym; 1699 const SummaryLogTy &SummaryLog; 1700 bool GCEnabled; 1701 1702 public: 1703 CFRefReportVisitor(SymbolRef sym, bool gcEnabled, const SummaryLogTy &log) 1704 : Sym(sym), SummaryLog(log), GCEnabled(gcEnabled) {} 1705 1706 virtual void Profile(llvm::FoldingSetNodeID &ID) const { 1707 static int x = 0; 1708 ID.AddPointer(&x); 1709 ID.AddPointer(Sym); 1710 } 1711 1712 virtual PathDiagnosticPiece *VisitNode(const ExplodedNode *N, 1713 const ExplodedNode *PrevN, 1714 BugReporterContext &BRC, 1715 BugReport &BR); 1716 1717 virtual PathDiagnosticPiece *getEndPath(BugReporterContext &BRC, 1718 const ExplodedNode *N, 1719 BugReport &BR); 1720 }; 1721 1722 class CFRefLeakReportVisitor : public CFRefReportVisitor { 1723 public: 1724 CFRefLeakReportVisitor(SymbolRef sym, bool GCEnabled, 1725 const SummaryLogTy &log) 1726 : CFRefReportVisitor(sym, GCEnabled, log) {} 1727 1728 PathDiagnosticPiece *getEndPath(BugReporterContext &BRC, 1729 const ExplodedNode *N, 1730 BugReport &BR); 1731 }; 1732 1733 class CFRefReport : public BugReport { 1734 void addGCModeDescription(const LangOptions &LOpts, bool GCEnabled); 1735 1736 public: 1737 CFRefReport(CFRefBug &D, const LangOptions &LOpts, bool GCEnabled, 1738 const SummaryLogTy &Log, ExplodedNode *n, SymbolRef sym, 1739 bool registerVisitor = true) 1740 : BugReport(D, D.getDescription(), n) { 1741 if (registerVisitor) 1742 addVisitor(new CFRefReportVisitor(sym, GCEnabled, Log)); 1743 addGCModeDescription(LOpts, GCEnabled); 1744 } 1745 1746 CFRefReport(CFRefBug &D, const LangOptions &LOpts, bool GCEnabled, 1747 const SummaryLogTy &Log, ExplodedNode *n, SymbolRef sym, 1748 StringRef endText) 1749 : BugReport(D, D.getDescription(), endText, n) { 1750 addVisitor(new CFRefReportVisitor(sym, GCEnabled, Log)); 1751 addGCModeDescription(LOpts, GCEnabled); 1752 } 1753 1754 virtual std::pair<ranges_iterator, ranges_iterator> getRanges() { 1755 const CFRefBug& BugTy = static_cast<CFRefBug&>(getBugType()); 1756 if (!BugTy.isLeak()) 1757 return BugReport::getRanges(); 1758 else 1759 return std::make_pair(ranges_iterator(), ranges_iterator()); 1760 } 1761 }; 1762 1763 class CFRefLeakReport : public CFRefReport { 1764 const MemRegion* AllocBinding; 1765 1766 public: 1767 CFRefLeakReport(CFRefBug &D, const LangOptions &LOpts, bool GCEnabled, 1768 const SummaryLogTy &Log, ExplodedNode *n, SymbolRef sym, 1769 CheckerContext &Ctx); 1770 1771 PathDiagnosticLocation getLocation(const SourceManager &SM) const { 1772 assert(Location.isValid()); 1773 return Location; 1774 } 1775 }; 1776} // end anonymous namespace 1777 1778void CFRefReport::addGCModeDescription(const LangOptions &LOpts, 1779 bool GCEnabled) { 1780 const char *GCModeDescription = 0; 1781 1782 switch (LOpts.getGC()) { 1783 case LangOptions::GCOnly: 1784 assert(GCEnabled); 1785 GCModeDescription = "Code is compiled to only use garbage collection"; 1786 break; 1787 1788 case LangOptions::NonGC: 1789 assert(!GCEnabled); 1790 GCModeDescription = "Code is compiled to use reference counts"; 1791 break; 1792 1793 case LangOptions::HybridGC: 1794 if (GCEnabled) { 1795 GCModeDescription = "Code is compiled to use either garbage collection " 1796 "(GC) or reference counts (non-GC). The bug occurs " 1797 "with GC enabled"; 1798 break; 1799 } else { 1800 GCModeDescription = "Code is compiled to use either garbage collection " 1801 "(GC) or reference counts (non-GC). The bug occurs " 1802 "in non-GC mode"; 1803 break; 1804 } 1805 } 1806 1807 assert(GCModeDescription && "invalid/unknown GC mode"); 1808 addExtraText(GCModeDescription); 1809} 1810 1811// FIXME: This should be a method on SmallVector. 1812static inline bool contains(const SmallVectorImpl<ArgEffect>& V, 1813 ArgEffect X) { 1814 for (SmallVectorImpl<ArgEffect>::const_iterator I=V.begin(), E=V.end(); 1815 I!=E; ++I) 1816 if (*I == X) return true; 1817 1818 return false; 1819} 1820 1821static bool isPropertyAccess(const Stmt *S, ParentMap &PM) { 1822 unsigned maxDepth = 4; 1823 while (S && maxDepth) { 1824 if (const PseudoObjectExpr *PO = dyn_cast<PseudoObjectExpr>(S)) { 1825 if (!isa<ObjCMessageExpr>(PO->getSyntacticForm())) 1826 return true; 1827 return false; 1828 } 1829 S = PM.getParent(S); 1830 --maxDepth; 1831 } 1832 return false; 1833} 1834 1835PathDiagnosticPiece *CFRefReportVisitor::VisitNode(const ExplodedNode *N, 1836 const ExplodedNode *PrevN, 1837 BugReporterContext &BRC, 1838 BugReport &BR) { 1839 1840 if (!isa<StmtPoint>(N->getLocation())) 1841 return NULL; 1842 1843 // Check if the type state has changed. 1844 ProgramStateRef PrevSt = PrevN->getState(); 1845 ProgramStateRef CurrSt = N->getState(); 1846 const LocationContext *LCtx = N->getLocationContext(); 1847 1848 const RefVal* CurrT = CurrSt->get<RefBindings>(Sym); 1849 if (!CurrT) return NULL; 1850 1851 const RefVal &CurrV = *CurrT; 1852 const RefVal *PrevT = PrevSt->get<RefBindings>(Sym); 1853 1854 // Create a string buffer to constain all the useful things we want 1855 // to tell the user. 1856 std::string sbuf; 1857 llvm::raw_string_ostream os(sbuf); 1858 1859 // This is the allocation site since the previous node had no bindings 1860 // for this symbol. 1861 if (!PrevT) { 1862 const Stmt *S = cast<StmtPoint>(N->getLocation()).getStmt(); 1863 1864 if (const CallExpr *CE = dyn_cast<CallExpr>(S)) { 1865 // Get the name of the callee (if it is available). 1866 SVal X = CurrSt->getSValAsScalarOrLoc(CE->getCallee(), LCtx); 1867 if (const FunctionDecl *FD = X.getAsFunctionDecl()) 1868 os << "Call to function '" << *FD << '\''; 1869 else 1870 os << "function call"; 1871 } 1872 else { 1873 assert(isa<ObjCMessageExpr>(S)); 1874 // The message expression may have between written directly or as 1875 // a property access. Lazily determine which case we are looking at. 1876 os << (isPropertyAccess(S, N->getParentMap()) ? "Property" : "Method"); 1877 } 1878 1879 if (CurrV.getObjKind() == RetEffect::CF) { 1880 os << " returns a Core Foundation object with a "; 1881 } 1882 else { 1883 assert (CurrV.getObjKind() == RetEffect::ObjC); 1884 os << " returns an Objective-C object with a "; 1885 } 1886 1887 if (CurrV.isOwned()) { 1888 os << "+1 retain count"; 1889 1890 if (GCEnabled) { 1891 assert(CurrV.getObjKind() == RetEffect::CF); 1892 os << ". " 1893 "Core Foundation objects are not automatically garbage collected."; 1894 } 1895 } 1896 else { 1897 assert (CurrV.isNotOwned()); 1898 os << "+0 retain count"; 1899 } 1900 1901 PathDiagnosticLocation Pos(S, BRC.getSourceManager(), 1902 N->getLocationContext()); 1903 return new PathDiagnosticEventPiece(Pos, os.str()); 1904 } 1905 1906 // Gather up the effects that were performed on the object at this 1907 // program point 1908 SmallVector<ArgEffect, 2> AEffects; 1909 1910 const ExplodedNode *OrigNode = BRC.getNodeResolver().getOriginalNode(N); 1911 if (const RetainSummary *Summ = SummaryLog.lookup(OrigNode)) { 1912 // We only have summaries attached to nodes after evaluating CallExpr and 1913 // ObjCMessageExprs. 1914 const Stmt *S = cast<StmtPoint>(N->getLocation()).getStmt(); 1915 1916 if (const CallExpr *CE = dyn_cast<CallExpr>(S)) { 1917 // Iterate through the parameter expressions and see if the symbol 1918 // was ever passed as an argument. 1919 unsigned i = 0; 1920 1921 for (CallExpr::const_arg_iterator AI=CE->arg_begin(), AE=CE->arg_end(); 1922 AI!=AE; ++AI, ++i) { 1923 1924 // Retrieve the value of the argument. Is it the symbol 1925 // we are interested in? 1926 if (CurrSt->getSValAsScalarOrLoc(*AI, LCtx).getAsLocSymbol() != Sym) 1927 continue; 1928 1929 // We have an argument. Get the effect! 1930 AEffects.push_back(Summ->getArg(i)); 1931 } 1932 } 1933 else if (const ObjCMessageExpr *ME = dyn_cast<ObjCMessageExpr>(S)) { 1934 if (const Expr *receiver = ME->getInstanceReceiver()) 1935 if (CurrSt->getSValAsScalarOrLoc(receiver, LCtx) 1936 .getAsLocSymbol() == Sym) { 1937 // The symbol we are tracking is the receiver. 1938 AEffects.push_back(Summ->getReceiverEffect()); 1939 } 1940 } 1941 } 1942 1943 do { 1944 // Get the previous type state. 1945 RefVal PrevV = *PrevT; 1946 1947 // Specially handle -dealloc. 1948 if (!GCEnabled && contains(AEffects, Dealloc)) { 1949 // Determine if the object's reference count was pushed to zero. 1950 assert(!(PrevV == CurrV) && "The typestate *must* have changed."); 1951 // We may not have transitioned to 'release' if we hit an error. 1952 // This case is handled elsewhere. 1953 if (CurrV.getKind() == RefVal::Released) { 1954 assert(CurrV.getCombinedCounts() == 0); 1955 os << "Object released by directly sending the '-dealloc' message"; 1956 break; 1957 } 1958 } 1959 1960 // Specially handle CFMakeCollectable and friends. 1961 if (contains(AEffects, MakeCollectable)) { 1962 // Get the name of the function. 1963 const Stmt *S = cast<StmtPoint>(N->getLocation()).getStmt(); 1964 SVal X = 1965 CurrSt->getSValAsScalarOrLoc(cast<CallExpr>(S)->getCallee(), LCtx); 1966 const FunctionDecl *FD = X.getAsFunctionDecl(); 1967 1968 if (GCEnabled) { 1969 // Determine if the object's reference count was pushed to zero. 1970 assert(!(PrevV == CurrV) && "The typestate *must* have changed."); 1971 1972 os << "In GC mode a call to '" << *FD 1973 << "' decrements an object's retain count and registers the " 1974 "object with the garbage collector. "; 1975 1976 if (CurrV.getKind() == RefVal::Released) { 1977 assert(CurrV.getCount() == 0); 1978 os << "Since it now has a 0 retain count the object can be " 1979 "automatically collected by the garbage collector."; 1980 } 1981 else 1982 os << "An object must have a 0 retain count to be garbage collected. " 1983 "After this call its retain count is +" << CurrV.getCount() 1984 << '.'; 1985 } 1986 else 1987 os << "When GC is not enabled a call to '" << *FD 1988 << "' has no effect on its argument."; 1989 1990 // Nothing more to say. 1991 break; 1992 } 1993 1994 // Determine if the typestate has changed. 1995 if (!(PrevV == CurrV)) 1996 switch (CurrV.getKind()) { 1997 case RefVal::Owned: 1998 case RefVal::NotOwned: 1999 2000 if (PrevV.getCount() == CurrV.getCount()) { 2001 // Did an autorelease message get sent? 2002 if (PrevV.getAutoreleaseCount() == CurrV.getAutoreleaseCount()) 2003 return 0; 2004 2005 assert(PrevV.getAutoreleaseCount() < CurrV.getAutoreleaseCount()); 2006 os << "Object sent -autorelease message"; 2007 break; 2008 } 2009 2010 if (PrevV.getCount() > CurrV.getCount()) 2011 os << "Reference count decremented."; 2012 else 2013 os << "Reference count incremented."; 2014 2015 if (unsigned Count = CurrV.getCount()) 2016 os << " The object now has a +" << Count << " retain count."; 2017 2018 if (PrevV.getKind() == RefVal::Released) { 2019 assert(GCEnabled && CurrV.getCount() > 0); 2020 os << " The object is not eligible for garbage collection until the " 2021 "retain count reaches 0 again."; 2022 } 2023 2024 break; 2025 2026 case RefVal::Released: 2027 os << "Object released."; 2028 break; 2029 2030 case RefVal::ReturnedOwned: 2031 os << "Object returned to caller as an owning reference (single retain " 2032 "count transferred to caller)"; 2033 break; 2034 2035 case RefVal::ReturnedNotOwned: 2036 os << "Object returned to caller with a +0 retain count"; 2037 break; 2038 2039 default: 2040 return NULL; 2041 } 2042 2043 // Emit any remaining diagnostics for the argument effects (if any). 2044 for (SmallVectorImpl<ArgEffect>::iterator I=AEffects.begin(), 2045 E=AEffects.end(); I != E; ++I) { 2046 2047 // A bunch of things have alternate behavior under GC. 2048 if (GCEnabled) 2049 switch (*I) { 2050 default: break; 2051 case Autorelease: 2052 os << "In GC mode an 'autorelease' has no effect."; 2053 continue; 2054 case IncRefMsg: 2055 os << "In GC mode the 'retain' message has no effect."; 2056 continue; 2057 case DecRefMsg: 2058 os << "In GC mode the 'release' message has no effect."; 2059 continue; 2060 } 2061 } 2062 } while (0); 2063 2064 if (os.str().empty()) 2065 return 0; // We have nothing to say! 2066 2067 const Stmt *S = cast<StmtPoint>(N->getLocation()).getStmt(); 2068 PathDiagnosticLocation Pos(S, BRC.getSourceManager(), 2069 N->getLocationContext()); 2070 PathDiagnosticPiece *P = new PathDiagnosticEventPiece(Pos, os.str()); 2071 2072 // Add the range by scanning the children of the statement for any bindings 2073 // to Sym. 2074 for (Stmt::const_child_iterator I = S->child_begin(), E = S->child_end(); 2075 I!=E; ++I) 2076 if (const Expr *Exp = dyn_cast_or_null<Expr>(*I)) 2077 if (CurrSt->getSValAsScalarOrLoc(Exp, LCtx).getAsLocSymbol() == Sym) { 2078 P->addRange(Exp->getSourceRange()); 2079 break; 2080 } 2081 2082 return P; 2083} 2084 2085namespace { 2086 class FindUniqueBinding : 2087 public StoreManager::BindingsHandler { 2088 SymbolRef Sym; 2089 const MemRegion* Binding; 2090 bool First; 2091 2092 public: 2093 FindUniqueBinding(SymbolRef sym) : Sym(sym), Binding(0), First(true) {} 2094 2095 bool HandleBinding(StoreManager& SMgr, Store store, const MemRegion* R, 2096 SVal val) { 2097 2098 SymbolRef SymV = val.getAsSymbol(); 2099 if (!SymV || SymV != Sym) 2100 return true; 2101 2102 if (Binding) { 2103 First = false; 2104 return false; 2105 } 2106 else 2107 Binding = R; 2108 2109 return true; 2110 } 2111 2112 operator bool() { return First && Binding; } 2113 const MemRegion *getRegion() { return Binding; } 2114 }; 2115} 2116 2117// Find the first node in the current function context that referred to the 2118// tracked symbol and the memory location that value was stored to. Note, the 2119// value is only reported if the allocation occurred in the same function as 2120// the leak. 2121static std::pair<const ExplodedNode*,const MemRegion*> 2122GetAllocationSite(ProgramStateManager& StateMgr, const ExplodedNode *N, 2123 SymbolRef Sym) { 2124 const ExplodedNode *Last = N; 2125 const MemRegion* FirstBinding = 0; 2126 const LocationContext *LeakContext = N->getLocationContext(); 2127 2128 while (N) { 2129 ProgramStateRef St = N->getState(); 2130 RefBindings B = St->get<RefBindings>(); 2131 2132 if (!B.lookup(Sym)) 2133 break; 2134 2135 FindUniqueBinding FB(Sym); 2136 StateMgr.iterBindings(St, FB); 2137 if (FB) FirstBinding = FB.getRegion(); 2138 2139 // Allocation node, is the last node in the current context in which the 2140 // symbol was tracked. 2141 if (N->getLocationContext() == LeakContext) 2142 Last = N; 2143 2144 N = N->pred_empty() ? NULL : *(N->pred_begin()); 2145 } 2146 2147 // If allocation happened in a function different from the leak node context, 2148 // do not report the binding. 2149 if (N->getLocationContext() != LeakContext) { 2150 FirstBinding = 0; 2151 } 2152 2153 return std::make_pair(Last, FirstBinding); 2154} 2155 2156PathDiagnosticPiece* 2157CFRefReportVisitor::getEndPath(BugReporterContext &BRC, 2158 const ExplodedNode *EndN, 2159 BugReport &BR) { 2160 // Tell the BugReporterContext to report cases when the tracked symbol is 2161 // assigned to different variables, etc. 2162 BRC.addNotableSymbol(Sym); 2163 return BugReporterVisitor::getDefaultEndPath(BRC, EndN, BR); 2164} 2165 2166PathDiagnosticPiece* 2167CFRefLeakReportVisitor::getEndPath(BugReporterContext &BRC, 2168 const ExplodedNode *EndN, 2169 BugReport &BR) { 2170 2171 // Tell the BugReporterContext to report cases when the tracked symbol is 2172 // assigned to different variables, etc. 2173 BRC.addNotableSymbol(Sym); 2174 2175 // We are reporting a leak. Walk up the graph to get to the first node where 2176 // the symbol appeared, and also get the first VarDecl that tracked object 2177 // is stored to. 2178 const ExplodedNode *AllocNode = 0; 2179 const MemRegion* FirstBinding = 0; 2180 2181 llvm::tie(AllocNode, FirstBinding) = 2182 GetAllocationSite(BRC.getStateManager(), EndN, Sym); 2183 2184 SourceManager& SM = BRC.getSourceManager(); 2185 2186 // Compute an actual location for the leak. Sometimes a leak doesn't 2187 // occur at an actual statement (e.g., transition between blocks; end 2188 // of function) so we need to walk the graph and compute a real location. 2189 const ExplodedNode *LeakN = EndN; 2190 PathDiagnosticLocation L = PathDiagnosticLocation::createEndOfPath(LeakN, SM); 2191 2192 std::string sbuf; 2193 llvm::raw_string_ostream os(sbuf); 2194 2195 os << "Object leaked: "; 2196 2197 if (FirstBinding) { 2198 os << "object allocated and stored into '" 2199 << FirstBinding->getString() << '\''; 2200 } 2201 else 2202 os << "allocated object"; 2203 2204 // Get the retain count. 2205 const RefVal* RV = EndN->getState()->get<RefBindings>(Sym); 2206 2207 if (RV->getKind() == RefVal::ErrorLeakReturned) { 2208 // FIXME: Per comments in rdar://6320065, "create" only applies to CF 2209 // objects. Only "copy", "alloc", "retain" and "new" transfer ownership 2210 // to the caller for NS objects. 2211 const Decl *D = &EndN->getCodeDecl(); 2212 if (const ObjCMethodDecl *MD = dyn_cast<ObjCMethodDecl>(D)) { 2213 os << " is returned from a method whose name ('" 2214 << MD->getSelector().getAsString() 2215 << "') does not start with 'copy', 'mutableCopy', 'alloc' or 'new'." 2216 " This violates the naming convention rules" 2217 " given in the Memory Management Guide for Cocoa"; 2218 } 2219 else { 2220 const FunctionDecl *FD = cast<FunctionDecl>(D); 2221 os << " is returned from a function whose name ('" 2222 << *FD 2223 << "') does not contain 'Copy' or 'Create'. This violates the naming" 2224 " convention rules given in the Memory Management Guide for Core" 2225 " Foundation"; 2226 } 2227 } 2228 else if (RV->getKind() == RefVal::ErrorGCLeakReturned) { 2229 ObjCMethodDecl &MD = cast<ObjCMethodDecl>(EndN->getCodeDecl()); 2230 os << " and returned from method '" << MD.getSelector().getAsString() 2231 << "' is potentially leaked when using garbage collection. Callers " 2232 "of this method do not expect a returned object with a +1 retain " 2233 "count since they expect the object to be managed by the garbage " 2234 "collector"; 2235 } 2236 else 2237 os << " is not referenced later in this execution path and has a retain " 2238 "count of +" << RV->getCount(); 2239 2240 return new PathDiagnosticEventPiece(L, os.str()); 2241} 2242 2243CFRefLeakReport::CFRefLeakReport(CFRefBug &D, const LangOptions &LOpts, 2244 bool GCEnabled, const SummaryLogTy &Log, 2245 ExplodedNode *n, SymbolRef sym, 2246 CheckerContext &Ctx) 2247: CFRefReport(D, LOpts, GCEnabled, Log, n, sym, false) { 2248 2249 // Most bug reports are cached at the location where they occurred. 2250 // With leaks, we want to unique them by the location where they were 2251 // allocated, and only report a single path. To do this, we need to find 2252 // the allocation site of a piece of tracked memory, which we do via a 2253 // call to GetAllocationSite. This will walk the ExplodedGraph backwards. 2254 // Note that this is *not* the trimmed graph; we are guaranteed, however, 2255 // that all ancestor nodes that represent the allocation site have the 2256 // same SourceLocation. 2257 const ExplodedNode *AllocNode = 0; 2258 2259 const SourceManager& SMgr = Ctx.getSourceManager(); 2260 2261 llvm::tie(AllocNode, AllocBinding) = // Set AllocBinding. 2262 GetAllocationSite(Ctx.getStateManager(), getErrorNode(), sym); 2263 2264 // Get the SourceLocation for the allocation site. 2265 ProgramPoint P = AllocNode->getLocation(); 2266 const Stmt *AllocStmt = cast<PostStmt>(P).getStmt(); 2267 Location = PathDiagnosticLocation::createBegin(AllocStmt, SMgr, 2268 n->getLocationContext()); 2269 // Fill in the description of the bug. 2270 Description.clear(); 2271 llvm::raw_string_ostream os(Description); 2272 os << "Potential leak "; 2273 if (GCEnabled) 2274 os << "(when using garbage collection) "; 2275 os << "of an object"; 2276 2277 // FIXME: AllocBinding doesn't get populated for RegionStore yet. 2278 if (AllocBinding) 2279 os << " stored into '" << AllocBinding->getString() << '\''; 2280 2281 addVisitor(new CFRefLeakReportVisitor(sym, GCEnabled, Log)); 2282} 2283 2284//===----------------------------------------------------------------------===// 2285// Main checker logic. 2286//===----------------------------------------------------------------------===// 2287 2288namespace { 2289class RetainCountChecker 2290 : public Checker< check::Bind, 2291 check::DeadSymbols, 2292 check::EndAnalysis, 2293 check::EndPath, 2294 check::PostStmt<BlockExpr>, 2295 check::PostStmt<CastExpr>, 2296 check::PostStmt<CallExpr>, 2297 check::PostStmt<CXXConstructExpr>, 2298 check::PostObjCMessage, 2299 check::PreStmt<ReturnStmt>, 2300 check::RegionChanges, 2301 eval::Assume, 2302 eval::Call > { 2303 mutable OwningPtr<CFRefBug> useAfterRelease, releaseNotOwned; 2304 mutable OwningPtr<CFRefBug> deallocGC, deallocNotOwned; 2305 mutable OwningPtr<CFRefBug> overAutorelease, returnNotOwnedForOwned; 2306 mutable OwningPtr<CFRefBug> leakWithinFunction, leakAtReturn; 2307 mutable OwningPtr<CFRefBug> leakWithinFunctionGC, leakAtReturnGC; 2308 2309 typedef llvm::DenseMap<SymbolRef, const SimpleProgramPointTag *> SymbolTagMap; 2310 2311 // This map is only used to ensure proper deletion of any allocated tags. 2312 mutable SymbolTagMap DeadSymbolTags; 2313 2314 mutable OwningPtr<RetainSummaryManager> Summaries; 2315 mutable OwningPtr<RetainSummaryManager> SummariesGC; 2316 2317 mutable ARCounts::Factory ARCountFactory; 2318 2319 mutable SummaryLogTy SummaryLog; 2320 mutable bool ShouldResetSummaryLog; 2321 2322public: 2323 RetainCountChecker() : ShouldResetSummaryLog(false) {} 2324 2325 virtual ~RetainCountChecker() { 2326 DeleteContainerSeconds(DeadSymbolTags); 2327 } 2328 2329 void checkEndAnalysis(ExplodedGraph &G, BugReporter &BR, 2330 ExprEngine &Eng) const { 2331 // FIXME: This is a hack to make sure the summary log gets cleared between 2332 // analyses of different code bodies. 2333 // 2334 // Why is this necessary? Because a checker's lifetime is tied to a 2335 // translation unit, but an ExplodedGraph's lifetime is just a code body. 2336 // Once in a blue moon, a new ExplodedNode will have the same address as an 2337 // old one with an associated summary, and the bug report visitor gets very 2338 // confused. (To make things worse, the summary lifetime is currently also 2339 // tied to a code body, so we get a crash instead of incorrect results.) 2340 // 2341 // Why is this a bad solution? Because if the lifetime of the ExplodedGraph 2342 // changes, things will start going wrong again. Really the lifetime of this 2343 // log needs to be tied to either the specific nodes in it or the entire 2344 // ExplodedGraph, not to a specific part of the code being analyzed. 2345 // 2346 // (Also, having stateful local data means that the same checker can't be 2347 // used from multiple threads, but a lot of checkers have incorrect 2348 // assumptions about that anyway. So that wasn't a priority at the time of 2349 // this fix.) 2350 // 2351 // This happens at the end of analysis, but bug reports are emitted /after/ 2352 // this point. So we can't just clear the summary log now. Instead, we mark 2353 // that the next time we access the summary log, it should be cleared. 2354 2355 // If we never reset the summary log during /this/ code body analysis, 2356 // there were no new summaries. There might still have been summaries from 2357 // the /last/ analysis, so clear them out to make sure the bug report 2358 // visitors don't get confused. 2359 if (ShouldResetSummaryLog) 2360 SummaryLog.clear(); 2361 2362 ShouldResetSummaryLog = !SummaryLog.empty(); 2363 } 2364 2365 CFRefBug *getLeakWithinFunctionBug(const LangOptions &LOpts, 2366 bool GCEnabled) const { 2367 if (GCEnabled) { 2368 if (!leakWithinFunctionGC) 2369 leakWithinFunctionGC.reset(new LeakWithinFunction("Leak of object when " 2370 "using garbage " 2371 "collection")); 2372 return leakWithinFunctionGC.get(); 2373 } else { 2374 if (!leakWithinFunction) { 2375 if (LOpts.getGC() == LangOptions::HybridGC) { 2376 leakWithinFunction.reset(new LeakWithinFunction("Leak of object when " 2377 "not using garbage " 2378 "collection (GC) in " 2379 "dual GC/non-GC " 2380 "code")); 2381 } else { 2382 leakWithinFunction.reset(new LeakWithinFunction("Leak")); 2383 } 2384 } 2385 return leakWithinFunction.get(); 2386 } 2387 } 2388 2389 CFRefBug *getLeakAtReturnBug(const LangOptions &LOpts, bool GCEnabled) const { 2390 if (GCEnabled) { 2391 if (!leakAtReturnGC) 2392 leakAtReturnGC.reset(new LeakAtReturn("Leak of returned object when " 2393 "using garbage collection")); 2394 return leakAtReturnGC.get(); 2395 } else { 2396 if (!leakAtReturn) { 2397 if (LOpts.getGC() == LangOptions::HybridGC) { 2398 leakAtReturn.reset(new LeakAtReturn("Leak of returned object when " 2399 "not using garbage collection " 2400 "(GC) in dual GC/non-GC code")); 2401 } else { 2402 leakAtReturn.reset(new LeakAtReturn("Leak of returned object")); 2403 } 2404 } 2405 return leakAtReturn.get(); 2406 } 2407 } 2408 2409 RetainSummaryManager &getSummaryManager(ASTContext &Ctx, 2410 bool GCEnabled) const { 2411 // FIXME: We don't support ARC being turned on and off during one analysis. 2412 // (nor, for that matter, do we support changing ASTContexts) 2413 bool ARCEnabled = (bool)Ctx.getLangOptions().ObjCAutoRefCount; 2414 if (GCEnabled) { 2415 if (!SummariesGC) 2416 SummariesGC.reset(new RetainSummaryManager(Ctx, true, ARCEnabled)); 2417 else 2418 assert(SummariesGC->isARCEnabled() == ARCEnabled); 2419 return *SummariesGC; 2420 } else { 2421 if (!Summaries) 2422 Summaries.reset(new RetainSummaryManager(Ctx, false, ARCEnabled)); 2423 else 2424 assert(Summaries->isARCEnabled() == ARCEnabled); 2425 return *Summaries; 2426 } 2427 } 2428 2429 RetainSummaryManager &getSummaryManager(CheckerContext &C) const { 2430 return getSummaryManager(C.getASTContext(), C.isObjCGCEnabled()); 2431 } 2432 2433 void printState(raw_ostream &Out, ProgramStateRef State, 2434 const char *NL, const char *Sep) const; 2435 2436 void checkBind(SVal loc, SVal val, const Stmt *S, CheckerContext &C) const; 2437 void checkPostStmt(const BlockExpr *BE, CheckerContext &C) const; 2438 void checkPostStmt(const CastExpr *CE, CheckerContext &C) const; 2439 2440 void checkPostStmt(const CallExpr *CE, CheckerContext &C) const; 2441 void checkPostStmt(const CXXConstructExpr *CE, CheckerContext &C) const; 2442 void checkPostObjCMessage(const ObjCMessage &Msg, CheckerContext &C) const; 2443 void checkSummary(const RetainSummary &Summ, const CallOrObjCMessage &Call, 2444 CheckerContext &C) const; 2445 2446 bool evalCall(const CallExpr *CE, CheckerContext &C) const; 2447 2448 ProgramStateRef evalAssume(ProgramStateRef state, SVal Cond, 2449 bool Assumption) const; 2450 2451 ProgramStateRef 2452 checkRegionChanges(ProgramStateRef state, 2453 const StoreManager::InvalidatedSymbols *invalidated, 2454 ArrayRef<const MemRegion *> ExplicitRegions, 2455 ArrayRef<const MemRegion *> Regions, 2456 const CallOrObjCMessage *Call) const; 2457 2458 bool wantsRegionChangeUpdate(ProgramStateRef state) const { 2459 return true; 2460 } 2461 2462 void checkPreStmt(const ReturnStmt *S, CheckerContext &C) const; 2463 void checkReturnWithRetEffect(const ReturnStmt *S, CheckerContext &C, 2464 ExplodedNode *Pred, RetEffect RE, RefVal X, 2465 SymbolRef Sym, ProgramStateRef state) const; 2466 2467 void checkDeadSymbols(SymbolReaper &SymReaper, CheckerContext &C) const; 2468 void checkEndPath(CheckerContext &C) const; 2469 2470 ProgramStateRef updateSymbol(ProgramStateRef state, SymbolRef sym, 2471 RefVal V, ArgEffect E, RefVal::Kind &hasErr, 2472 CheckerContext &C) const; 2473 2474 void processNonLeakError(ProgramStateRef St, SourceRange ErrorRange, 2475 RefVal::Kind ErrorKind, SymbolRef Sym, 2476 CheckerContext &C) const; 2477 2478 const ProgramPointTag *getDeadSymbolTag(SymbolRef sym) const; 2479 2480 ProgramStateRef handleSymbolDeath(ProgramStateRef state, 2481 SymbolRef sid, RefVal V, 2482 SmallVectorImpl<SymbolRef> &Leaked) const; 2483 2484 std::pair<ExplodedNode *, ProgramStateRef > 2485 handleAutoreleaseCounts(ProgramStateRef state, 2486 GenericNodeBuilderRefCount Bd, ExplodedNode *Pred, 2487 CheckerContext &Ctx, SymbolRef Sym, RefVal V) const; 2488 2489 ExplodedNode *processLeaks(ProgramStateRef state, 2490 SmallVectorImpl<SymbolRef> &Leaked, 2491 GenericNodeBuilderRefCount &Builder, 2492 CheckerContext &Ctx, 2493 ExplodedNode *Pred = 0) const; 2494}; 2495} // end anonymous namespace 2496 2497namespace { 2498class StopTrackingCallback : public SymbolVisitor { 2499 ProgramStateRef state; 2500public: 2501 StopTrackingCallback(ProgramStateRef st) : state(st) {} 2502 ProgramStateRef getState() const { return state; } 2503 2504 bool VisitSymbol(SymbolRef sym) { 2505 state = state->remove<RefBindings>(sym); 2506 return true; 2507 } 2508}; 2509} // end anonymous namespace 2510 2511//===----------------------------------------------------------------------===// 2512// Handle statements that may have an effect on refcounts. 2513//===----------------------------------------------------------------------===// 2514 2515void RetainCountChecker::checkPostStmt(const BlockExpr *BE, 2516 CheckerContext &C) const { 2517 2518 // Scan the BlockDecRefExprs for any object the retain count checker 2519 // may be tracking. 2520 if (!BE->getBlockDecl()->hasCaptures()) 2521 return; 2522 2523 ProgramStateRef state = C.getState(); 2524 const BlockDataRegion *R = 2525 cast<BlockDataRegion>(state->getSVal(BE, 2526 C.getLocationContext()).getAsRegion()); 2527 2528 BlockDataRegion::referenced_vars_iterator I = R->referenced_vars_begin(), 2529 E = R->referenced_vars_end(); 2530 2531 if (I == E) 2532 return; 2533 2534 // FIXME: For now we invalidate the tracking of all symbols passed to blocks 2535 // via captured variables, even though captured variables result in a copy 2536 // and in implicit increment/decrement of a retain count. 2537 SmallVector<const MemRegion*, 10> Regions; 2538 const LocationContext *LC = C.getLocationContext(); 2539 MemRegionManager &MemMgr = C.getSValBuilder().getRegionManager(); 2540 2541 for ( ; I != E; ++I) { 2542 const VarRegion *VR = *I; 2543 if (VR->getSuperRegion() == R) { 2544 VR = MemMgr.getVarRegion(VR->getDecl(), LC); 2545 } 2546 Regions.push_back(VR); 2547 } 2548 2549 state = 2550 state->scanReachableSymbols<StopTrackingCallback>(Regions.data(), 2551 Regions.data() + Regions.size()).getState(); 2552 C.addTransition(state); 2553} 2554 2555void RetainCountChecker::checkPostStmt(const CastExpr *CE, 2556 CheckerContext &C) const { 2557 const ObjCBridgedCastExpr *BE = dyn_cast<ObjCBridgedCastExpr>(CE); 2558 if (!BE) 2559 return; 2560 2561 ArgEffect AE = IncRef; 2562 2563 switch (BE->getBridgeKind()) { 2564 case clang::OBC_Bridge: 2565 // Do nothing. 2566 return; 2567 case clang::OBC_BridgeRetained: 2568 AE = IncRef; 2569 break; 2570 case clang::OBC_BridgeTransfer: 2571 AE = DecRefBridgedTransfered; 2572 break; 2573 } 2574 2575 ProgramStateRef state = C.getState(); 2576 SymbolRef Sym = state->getSVal(CE, C.getLocationContext()).getAsLocSymbol(); 2577 if (!Sym) 2578 return; 2579 const RefVal* T = state->get<RefBindings>(Sym); 2580 if (!T) 2581 return; 2582 2583 RefVal::Kind hasErr = (RefVal::Kind) 0; 2584 state = updateSymbol(state, Sym, *T, AE, hasErr, C); 2585 2586 if (hasErr) { 2587 // FIXME: If we get an error during a bridge cast, should we report it? 2588 // Should we assert that there is no error? 2589 return; 2590 } 2591 2592 C.addTransition(state); 2593} 2594 2595void RetainCountChecker::checkPostStmt(const CallExpr *CE, 2596 CheckerContext &C) const { 2597 // Get the callee. 2598 ProgramStateRef state = C.getState(); 2599 const Expr *Callee = CE->getCallee(); 2600 SVal L = state->getSVal(Callee, C.getLocationContext()); 2601 2602 RetainSummaryManager &Summaries = getSummaryManager(C); 2603 const RetainSummary *Summ = 0; 2604 2605 // FIXME: Better support for blocks. For now we stop tracking anything 2606 // that is passed to blocks. 2607 // FIXME: Need to handle variables that are "captured" by the block. 2608 if (dyn_cast_or_null<BlockDataRegion>(L.getAsRegion())) { 2609 Summ = Summaries.getPersistentStopSummary(); 2610 } else if (const FunctionDecl *FD = L.getAsFunctionDecl()) { 2611 Summ = Summaries.getSummary(FD); 2612 } else if (const CXXMemberCallExpr *me = dyn_cast<CXXMemberCallExpr>(CE)) { 2613 if (const CXXMethodDecl *MD = me->getMethodDecl()) 2614 Summ = Summaries.getSummary(MD); 2615 } 2616 2617 if (!Summ) 2618 Summ = Summaries.getDefaultSummary(); 2619 2620 checkSummary(*Summ, CallOrObjCMessage(CE, state, C.getLocationContext()), C); 2621} 2622 2623void RetainCountChecker::checkPostStmt(const CXXConstructExpr *CE, 2624 CheckerContext &C) const { 2625 const CXXConstructorDecl *Ctor = CE->getConstructor(); 2626 if (!Ctor) 2627 return; 2628 2629 RetainSummaryManager &Summaries = getSummaryManager(C); 2630 const RetainSummary *Summ = Summaries.getSummary(Ctor); 2631 2632 // If we didn't get a summary, this constructor doesn't affect retain counts. 2633 if (!Summ) 2634 return; 2635 2636 ProgramStateRef state = C.getState(); 2637 checkSummary(*Summ, CallOrObjCMessage(CE, state, C.getLocationContext()), C); 2638} 2639 2640void RetainCountChecker::checkPostObjCMessage(const ObjCMessage &Msg, 2641 CheckerContext &C) const { 2642 ProgramStateRef state = C.getState(); 2643 2644 RetainSummaryManager &Summaries = getSummaryManager(C); 2645 2646 const RetainSummary *Summ; 2647 if (Msg.isInstanceMessage()) { 2648 const LocationContext *LC = C.getLocationContext(); 2649 Summ = Summaries.getInstanceMethodSummary(Msg, state, LC); 2650 } else { 2651 Summ = Summaries.getClassMethodSummary(Msg); 2652 } 2653 2654 // If we didn't get a summary, this message doesn't affect retain counts. 2655 if (!Summ) 2656 return; 2657 2658 checkSummary(*Summ, CallOrObjCMessage(Msg, state, C.getLocationContext()), C); 2659} 2660 2661/// GetReturnType - Used to get the return type of a message expression or 2662/// function call with the intention of affixing that type to a tracked symbol. 2663/// While the the return type can be queried directly from RetEx, when 2664/// invoking class methods we augment to the return type to be that of 2665/// a pointer to the class (as opposed it just being id). 2666// FIXME: We may be able to do this with related result types instead. 2667// This function is probably overestimating. 2668static QualType GetReturnType(const Expr *RetE, ASTContext &Ctx) { 2669 QualType RetTy = RetE->getType(); 2670 // If RetE is not a message expression just return its type. 2671 // If RetE is a message expression, return its types if it is something 2672 /// more specific than id. 2673 if (const ObjCMessageExpr *ME = dyn_cast<ObjCMessageExpr>(RetE)) 2674 if (const ObjCObjectPointerType *PT = RetTy->getAs<ObjCObjectPointerType>()) 2675 if (PT->isObjCQualifiedIdType() || PT->isObjCIdType() || 2676 PT->isObjCClassType()) { 2677 // At this point we know the return type of the message expression is 2678 // id, id<...>, or Class. If we have an ObjCInterfaceDecl, we know this 2679 // is a call to a class method whose type we can resolve. In such 2680 // cases, promote the return type to XXX* (where XXX is the class). 2681 const ObjCInterfaceDecl *D = ME->getReceiverInterface(); 2682 return !D ? RetTy : 2683 Ctx.getObjCObjectPointerType(Ctx.getObjCInterfaceType(D)); 2684 } 2685 2686 return RetTy; 2687} 2688 2689void RetainCountChecker::checkSummary(const RetainSummary &Summ, 2690 const CallOrObjCMessage &CallOrMsg, 2691 CheckerContext &C) const { 2692 ProgramStateRef state = C.getState(); 2693 2694 // Evaluate the effect of the arguments. 2695 RefVal::Kind hasErr = (RefVal::Kind) 0; 2696 SourceRange ErrorRange; 2697 SymbolRef ErrorSym = 0; 2698 2699 for (unsigned idx = 0, e = CallOrMsg.getNumArgs(); idx != e; ++idx) { 2700 SVal V = CallOrMsg.getArgSVal(idx); 2701 2702 if (SymbolRef Sym = V.getAsLocSymbol()) { 2703 if (RefBindings::data_type *T = state->get<RefBindings>(Sym)) { 2704 state = updateSymbol(state, Sym, *T, Summ.getArg(idx), hasErr, C); 2705 if (hasErr) { 2706 ErrorRange = CallOrMsg.getArgSourceRange(idx); 2707 ErrorSym = Sym; 2708 break; 2709 } 2710 } 2711 } 2712 } 2713 2714 // Evaluate the effect on the message receiver. 2715 bool ReceiverIsTracked = false; 2716 if (!hasErr && CallOrMsg.isObjCMessage()) { 2717 const LocationContext *LC = C.getLocationContext(); 2718 SVal Receiver = CallOrMsg.getInstanceMessageReceiver(LC); 2719 if (SymbolRef Sym = Receiver.getAsLocSymbol()) { 2720 if (const RefVal *T = state->get<RefBindings>(Sym)) { 2721 ReceiverIsTracked = true; 2722 state = updateSymbol(state, Sym, *T, Summ.getReceiverEffect(), 2723 hasErr, C); 2724 if (hasErr) { 2725 ErrorRange = CallOrMsg.getReceiverSourceRange(); 2726 ErrorSym = Sym; 2727 } 2728 } 2729 } 2730 } 2731 2732 // Process any errors. 2733 if (hasErr) { 2734 processNonLeakError(state, ErrorRange, hasErr, ErrorSym, C); 2735 return; 2736 } 2737 2738 // Consult the summary for the return value. 2739 RetEffect RE = Summ.getRetEffect(); 2740 2741 if (RE.getKind() == RetEffect::OwnedWhenTrackedReceiver) { 2742 if (ReceiverIsTracked) 2743 RE = getSummaryManager(C).getObjAllocRetEffect(); 2744 else 2745 RE = RetEffect::MakeNoRet(); 2746 } 2747 2748 switch (RE.getKind()) { 2749 default: 2750 llvm_unreachable("Unhandled RetEffect."); 2751 2752 case RetEffect::NoRet: 2753 // No work necessary. 2754 break; 2755 2756 case RetEffect::OwnedAllocatedSymbol: 2757 case RetEffect::OwnedSymbol: { 2758 SymbolRef Sym = state->getSVal(CallOrMsg.getOriginExpr(), 2759 C.getLocationContext()).getAsSymbol(); 2760 if (!Sym) 2761 break; 2762 2763 // Use the result type from callOrMsg as it automatically adjusts 2764 // for methods/functions that return references. 2765 QualType ResultTy = CallOrMsg.getResultType(C.getASTContext()); 2766 state = state->set<RefBindings>(Sym, RefVal::makeOwned(RE.getObjKind(), 2767 ResultTy)); 2768 2769 // FIXME: Add a flag to the checker where allocations are assumed to 2770 // *not* fail. (The code below is out-of-date, though.) 2771#if 0 2772 if (RE.getKind() == RetEffect::OwnedAllocatedSymbol) { 2773 bool isFeasible; 2774 state = state.assume(loc::SymbolVal(Sym), true, isFeasible); 2775 assert(isFeasible && "Cannot assume fresh symbol is non-null."); 2776 } 2777#endif 2778 2779 break; 2780 } 2781 2782 case RetEffect::GCNotOwnedSymbol: 2783 case RetEffect::ARCNotOwnedSymbol: 2784 case RetEffect::NotOwnedSymbol: { 2785 const Expr *Ex = CallOrMsg.getOriginExpr(); 2786 SymbolRef Sym = state->getSVal(Ex, C.getLocationContext()).getAsSymbol(); 2787 if (!Sym) 2788 break; 2789 2790 // Use GetReturnType in order to give [NSFoo alloc] the type NSFoo *. 2791 QualType ResultTy = GetReturnType(Ex, C.getASTContext()); 2792 state = state->set<RefBindings>(Sym, RefVal::makeNotOwned(RE.getObjKind(), 2793 ResultTy)); 2794 break; 2795 } 2796 } 2797 2798 // This check is actually necessary; otherwise the statement builder thinks 2799 // we've hit a previously-found path. 2800 // Normally addTransition takes care of this, but we want the node pointer. 2801 ExplodedNode *NewNode; 2802 if (state == C.getState()) { 2803 NewNode = C.getPredecessor(); 2804 } else { 2805 NewNode = C.addTransition(state); 2806 } 2807 2808 // Annotate the node with summary we used. 2809 if (NewNode) { 2810 // FIXME: This is ugly. See checkEndAnalysis for why it's necessary. 2811 if (ShouldResetSummaryLog) { 2812 SummaryLog.clear(); 2813 ShouldResetSummaryLog = false; 2814 } 2815 SummaryLog[NewNode] = &Summ; 2816 } 2817} 2818 2819 2820ProgramStateRef 2821RetainCountChecker::updateSymbol(ProgramStateRef state, SymbolRef sym, 2822 RefVal V, ArgEffect E, RefVal::Kind &hasErr, 2823 CheckerContext &C) const { 2824 // In GC mode [... release] and [... retain] do nothing. 2825 // In ARC mode they shouldn't exist at all, but we just ignore them. 2826 bool IgnoreRetainMsg = C.isObjCGCEnabled(); 2827 if (!IgnoreRetainMsg) 2828 IgnoreRetainMsg = (bool)C.getASTContext().getLangOptions().ObjCAutoRefCount; 2829 2830 switch (E) { 2831 default: break; 2832 case IncRefMsg: E = IgnoreRetainMsg ? DoNothing : IncRef; break; 2833 case DecRefMsg: E = IgnoreRetainMsg ? DoNothing : DecRef; break; 2834 case MakeCollectable: E = C.isObjCGCEnabled() ? DecRef : DoNothing; break; 2835 case NewAutoreleasePool: E = C.isObjCGCEnabled() ? DoNothing : 2836 NewAutoreleasePool; break; 2837 } 2838 2839 // Handle all use-after-releases. 2840 if (!C.isObjCGCEnabled() && V.getKind() == RefVal::Released) { 2841 V = V ^ RefVal::ErrorUseAfterRelease; 2842 hasErr = V.getKind(); 2843 return state->set<RefBindings>(sym, V); 2844 } 2845 2846 switch (E) { 2847 case DecRefMsg: 2848 case IncRefMsg: 2849 case MakeCollectable: 2850 llvm_unreachable("DecRefMsg/IncRefMsg/MakeCollectable already converted"); 2851 2852 case Dealloc: 2853 // Any use of -dealloc in GC is *bad*. 2854 if (C.isObjCGCEnabled()) { 2855 V = V ^ RefVal::ErrorDeallocGC; 2856 hasErr = V.getKind(); 2857 break; 2858 } 2859 2860 switch (V.getKind()) { 2861 default: 2862 llvm_unreachable("Invalid RefVal state for an explicit dealloc."); 2863 case RefVal::Owned: 2864 // The object immediately transitions to the released state. 2865 V = V ^ RefVal::Released; 2866 V.clearCounts(); 2867 return state->set<RefBindings>(sym, V); 2868 case RefVal::NotOwned: 2869 V = V ^ RefVal::ErrorDeallocNotOwned; 2870 hasErr = V.getKind(); 2871 break; 2872 } 2873 break; 2874 2875 case NewAutoreleasePool: 2876 assert(!C.isObjCGCEnabled()); 2877 return state->add<AutoreleaseStack>(sym); 2878 2879 case MayEscape: 2880 if (V.getKind() == RefVal::Owned) { 2881 V = V ^ RefVal::NotOwned; 2882 break; 2883 } 2884 2885 // Fall-through. 2886 2887 case DoNothing: 2888 return state; 2889 2890 case Autorelease: 2891 if (C.isObjCGCEnabled()) 2892 return state; 2893 2894 // Update the autorelease counts. 2895 state = SendAutorelease(state, ARCountFactory, sym); 2896 V = V.autorelease(); 2897 break; 2898 2899 case StopTracking: 2900 return state->remove<RefBindings>(sym); 2901 2902 case IncRef: 2903 switch (V.getKind()) { 2904 default: 2905 llvm_unreachable("Invalid RefVal state for a retain."); 2906 case RefVal::Owned: 2907 case RefVal::NotOwned: 2908 V = V + 1; 2909 break; 2910 case RefVal::Released: 2911 // Non-GC cases are handled above. 2912 assert(C.isObjCGCEnabled()); 2913 V = (V ^ RefVal::Owned) + 1; 2914 break; 2915 } 2916 break; 2917 2918 case SelfOwn: 2919 V = V ^ RefVal::NotOwned; 2920 // Fall-through. 2921 case DecRef: 2922 case DecRefBridgedTransfered: 2923 switch (V.getKind()) { 2924 default: 2925 // case 'RefVal::Released' handled above. 2926 llvm_unreachable("Invalid RefVal state for a release."); 2927 2928 case RefVal::Owned: 2929 assert(V.getCount() > 0); 2930 if (V.getCount() == 1) 2931 V = V ^ (E == DecRefBridgedTransfered ? 2932 RefVal::NotOwned : RefVal::Released); 2933 V = V - 1; 2934 break; 2935 2936 case RefVal::NotOwned: 2937 if (V.getCount() > 0) 2938 V = V - 1; 2939 else { 2940 V = V ^ RefVal::ErrorReleaseNotOwned; 2941 hasErr = V.getKind(); 2942 } 2943 break; 2944 2945 case RefVal::Released: 2946 // Non-GC cases are handled above. 2947 assert(C.isObjCGCEnabled()); 2948 V = V ^ RefVal::ErrorUseAfterRelease; 2949 hasErr = V.getKind(); 2950 break; 2951 } 2952 break; 2953 } 2954 return state->set<RefBindings>(sym, V); 2955} 2956 2957void RetainCountChecker::processNonLeakError(ProgramStateRef St, 2958 SourceRange ErrorRange, 2959 RefVal::Kind ErrorKind, 2960 SymbolRef Sym, 2961 CheckerContext &C) const { 2962 ExplodedNode *N = C.generateSink(St); 2963 if (!N) 2964 return; 2965 2966 CFRefBug *BT; 2967 switch (ErrorKind) { 2968 default: 2969 llvm_unreachable("Unhandled error."); 2970 case RefVal::ErrorUseAfterRelease: 2971 if (!useAfterRelease) 2972 useAfterRelease.reset(new UseAfterRelease()); 2973 BT = &*useAfterRelease; 2974 break; 2975 case RefVal::ErrorReleaseNotOwned: 2976 if (!releaseNotOwned) 2977 releaseNotOwned.reset(new BadRelease()); 2978 BT = &*releaseNotOwned; 2979 break; 2980 case RefVal::ErrorDeallocGC: 2981 if (!deallocGC) 2982 deallocGC.reset(new DeallocGC()); 2983 BT = &*deallocGC; 2984 break; 2985 case RefVal::ErrorDeallocNotOwned: 2986 if (!deallocNotOwned) 2987 deallocNotOwned.reset(new DeallocNotOwned()); 2988 BT = &*deallocNotOwned; 2989 break; 2990 } 2991 2992 assert(BT); 2993 CFRefReport *report = new CFRefReport(*BT, C.getASTContext().getLangOptions(), 2994 C.isObjCGCEnabled(), SummaryLog, 2995 N, Sym); 2996 report->addRange(ErrorRange); 2997 C.EmitReport(report); 2998} 2999 3000//===----------------------------------------------------------------------===// 3001// Handle the return values of retain-count-related functions. 3002//===----------------------------------------------------------------------===// 3003 3004bool RetainCountChecker::evalCall(const CallExpr *CE, CheckerContext &C) const { 3005 // Get the callee. We're only interested in simple C functions. 3006 ProgramStateRef state = C.getState(); 3007 const FunctionDecl *FD = C.getCalleeDecl(CE); 3008 if (!FD) 3009 return false; 3010 3011 IdentifierInfo *II = FD->getIdentifier(); 3012 if (!II) 3013 return false; 3014 3015 // For now, we're only handling the functions that return aliases of their 3016 // arguments: CFRetain and CFMakeCollectable (and their families). 3017 // Eventually we should add other functions we can model entirely, 3018 // such as CFRelease, which don't invalidate their arguments or globals. 3019 if (CE->getNumArgs() != 1) 3020 return false; 3021 3022 // Get the name of the function. 3023 StringRef FName = II->getName(); 3024 FName = FName.substr(FName.find_first_not_of('_')); 3025 3026 // See if it's one of the specific functions we know how to eval. 3027 bool canEval = false; 3028 3029 QualType ResultTy = CE->getCallReturnType(); 3030 if (ResultTy->isObjCIdType()) { 3031 // Handle: id NSMakeCollectable(CFTypeRef) 3032 canEval = II->isStr("NSMakeCollectable"); 3033 } else if (ResultTy->isPointerType()) { 3034 // Handle: (CF|CG)Retain 3035 // CFMakeCollectable 3036 // It's okay to be a little sloppy here (CGMakeCollectable doesn't exist). 3037 if (cocoa::isRefType(ResultTy, "CF", FName) || 3038 cocoa::isRefType(ResultTy, "CG", FName)) { 3039 canEval = isRetain(FD, FName) || isMakeCollectable(FD, FName); 3040 } 3041 } 3042 3043 if (!canEval) 3044 return false; 3045 3046 // Bind the return value. 3047 const LocationContext *LCtx = C.getLocationContext(); 3048 SVal RetVal = state->getSVal(CE->getArg(0), LCtx); 3049 if (RetVal.isUnknown()) { 3050 // If the receiver is unknown, conjure a return value. 3051 SValBuilder &SVB = C.getSValBuilder(); 3052 unsigned Count = C.getCurrentBlockCount(); 3053 SVal RetVal = SVB.getConjuredSymbolVal(0, CE, LCtx, ResultTy, Count); 3054 } 3055 state = state->BindExpr(CE, LCtx, RetVal, false); 3056 3057 // FIXME: This should not be necessary, but otherwise the argument seems to be 3058 // considered alive during the next statement. 3059 if (const MemRegion *ArgRegion = RetVal.getAsRegion()) { 3060 // Save the refcount status of the argument. 3061 SymbolRef Sym = RetVal.getAsLocSymbol(); 3062 RefBindings::data_type *Binding = 0; 3063 if (Sym) 3064 Binding = state->get<RefBindings>(Sym); 3065 3066 // Invalidate the argument region. 3067 unsigned Count = C.getCurrentBlockCount(); 3068 state = state->invalidateRegions(ArgRegion, CE, Count, LCtx); 3069 3070 // Restore the refcount status of the argument. 3071 if (Binding) 3072 state = state->set<RefBindings>(Sym, *Binding); 3073 } 3074 3075 C.addTransition(state); 3076 return true; 3077} 3078 3079//===----------------------------------------------------------------------===// 3080// Handle return statements. 3081//===----------------------------------------------------------------------===// 3082 3083// Return true if the current LocationContext has no caller context. 3084static bool inTopFrame(CheckerContext &C) { 3085 const LocationContext *LC = C.getLocationContext(); 3086 return LC->getParent() == 0; 3087} 3088 3089void RetainCountChecker::checkPreStmt(const ReturnStmt *S, 3090 CheckerContext &C) const { 3091 3092 // Only adjust the reference count if this is the top-level call frame, 3093 // and not the result of inlining. In the future, we should do 3094 // better checking even for inlined calls, and see if they match 3095 // with their expected semantics (e.g., the method should return a retained 3096 // object, etc.). 3097 if (!inTopFrame(C)) 3098 return; 3099 3100 const Expr *RetE = S->getRetValue(); 3101 if (!RetE) 3102 return; 3103 3104 ProgramStateRef state = C.getState(); 3105 SymbolRef Sym = 3106 state->getSValAsScalarOrLoc(RetE, C.getLocationContext()).getAsLocSymbol(); 3107 if (!Sym) 3108 return; 3109 3110 // Get the reference count binding (if any). 3111 const RefVal *T = state->get<RefBindings>(Sym); 3112 if (!T) 3113 return; 3114 3115 // Change the reference count. 3116 RefVal X = *T; 3117 3118 switch (X.getKind()) { 3119 case RefVal::Owned: { 3120 unsigned cnt = X.getCount(); 3121 assert(cnt > 0); 3122 X.setCount(cnt - 1); 3123 X = X ^ RefVal::ReturnedOwned; 3124 break; 3125 } 3126 3127 case RefVal::NotOwned: { 3128 unsigned cnt = X.getCount(); 3129 if (cnt) { 3130 X.setCount(cnt - 1); 3131 X = X ^ RefVal::ReturnedOwned; 3132 } 3133 else { 3134 X = X ^ RefVal::ReturnedNotOwned; 3135 } 3136 break; 3137 } 3138 3139 default: 3140 return; 3141 } 3142 3143 // Update the binding. 3144 state = state->set<RefBindings>(Sym, X); 3145 ExplodedNode *Pred = C.addTransition(state); 3146 3147 // At this point we have updated the state properly. 3148 // Everything after this is merely checking to see if the return value has 3149 // been over- or under-retained. 3150 3151 // Did we cache out? 3152 if (!Pred) 3153 return; 3154 3155 // Update the autorelease counts. 3156 static SimpleProgramPointTag 3157 AutoreleaseTag("RetainCountChecker : Autorelease"); 3158 GenericNodeBuilderRefCount Bd(C, &AutoreleaseTag); 3159 llvm::tie(Pred, state) = handleAutoreleaseCounts(state, Bd, Pred, C, Sym, X); 3160 3161 // Did we cache out? 3162 if (!Pred) 3163 return; 3164 3165 // Get the updated binding. 3166 T = state->get<RefBindings>(Sym); 3167 assert(T); 3168 X = *T; 3169 3170 // Consult the summary of the enclosing method. 3171 RetainSummaryManager &Summaries = getSummaryManager(C); 3172 const Decl *CD = &Pred->getCodeDecl(); 3173 3174 if (const ObjCMethodDecl *MD = dyn_cast<ObjCMethodDecl>(CD)) { 3175 // Unlike regular functions, /all/ ObjC methods are assumed to always 3176 // follow Cocoa retain-count conventions, not just those with special 3177 // names or attributes. 3178 const RetainSummary *Summ = Summaries.getMethodSummary(MD); 3179 RetEffect RE = Summ ? Summ->getRetEffect() : RetEffect::MakeNoRet(); 3180 checkReturnWithRetEffect(S, C, Pred, RE, X, Sym, state); 3181 } 3182 3183 if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(CD)) { 3184 if (!isa<CXXMethodDecl>(FD)) 3185 if (const RetainSummary *Summ = Summaries.getSummary(FD)) 3186 checkReturnWithRetEffect(S, C, Pred, Summ->getRetEffect(), X, 3187 Sym, state); 3188 } 3189} 3190 3191void RetainCountChecker::checkReturnWithRetEffect(const ReturnStmt *S, 3192 CheckerContext &C, 3193 ExplodedNode *Pred, 3194 RetEffect RE, RefVal X, 3195 SymbolRef Sym, 3196 ProgramStateRef state) const { 3197 // Any leaks or other errors? 3198 if (X.isReturnedOwned() && X.getCount() == 0) { 3199 if (RE.getKind() != RetEffect::NoRet) { 3200 bool hasError = false; 3201 if (C.isObjCGCEnabled() && RE.getObjKind() == RetEffect::ObjC) { 3202 // Things are more complicated with garbage collection. If the 3203 // returned object is suppose to be an Objective-C object, we have 3204 // a leak (as the caller expects a GC'ed object) because no 3205 // method should return ownership unless it returns a CF object. 3206 hasError = true; 3207 X = X ^ RefVal::ErrorGCLeakReturned; 3208 } 3209 else if (!RE.isOwned()) { 3210 // Either we are using GC and the returned object is a CF type 3211 // or we aren't using GC. In either case, we expect that the 3212 // enclosing method is expected to return ownership. 3213 hasError = true; 3214 X = X ^ RefVal::ErrorLeakReturned; 3215 } 3216 3217 if (hasError) { 3218 // Generate an error node. 3219 state = state->set<RefBindings>(Sym, X); 3220 3221 static SimpleProgramPointTag 3222 ReturnOwnLeakTag("RetainCountChecker : ReturnsOwnLeak"); 3223 ExplodedNode *N = C.addTransition(state, Pred, &ReturnOwnLeakTag); 3224 if (N) { 3225 const LangOptions &LOpts = C.getASTContext().getLangOptions(); 3226 bool GCEnabled = C.isObjCGCEnabled(); 3227 CFRefReport *report = 3228 new CFRefLeakReport(*getLeakAtReturnBug(LOpts, GCEnabled), 3229 LOpts, GCEnabled, SummaryLog, 3230 N, Sym, C); 3231 C.EmitReport(report); 3232 } 3233 } 3234 } 3235 } else if (X.isReturnedNotOwned()) { 3236 if (RE.isOwned()) { 3237 // Trying to return a not owned object to a caller expecting an 3238 // owned object. 3239 state = state->set<RefBindings>(Sym, X ^ RefVal::ErrorReturnedNotOwned); 3240 3241 static SimpleProgramPointTag 3242 ReturnNotOwnedTag("RetainCountChecker : ReturnNotOwnedForOwned"); 3243 ExplodedNode *N = C.addTransition(state, Pred, &ReturnNotOwnedTag); 3244 if (N) { 3245 if (!returnNotOwnedForOwned) 3246 returnNotOwnedForOwned.reset(new ReturnedNotOwnedForOwned()); 3247 3248 CFRefReport *report = 3249 new CFRefReport(*returnNotOwnedForOwned, 3250 C.getASTContext().getLangOptions(), 3251 C.isObjCGCEnabled(), SummaryLog, N, Sym); 3252 C.EmitReport(report); 3253 } 3254 } 3255 } 3256} 3257 3258//===----------------------------------------------------------------------===// 3259// Check various ways a symbol can be invalidated. 3260//===----------------------------------------------------------------------===// 3261 3262void RetainCountChecker::checkBind(SVal loc, SVal val, const Stmt *S, 3263 CheckerContext &C) const { 3264 // Are we storing to something that causes the value to "escape"? 3265 bool escapes = true; 3266 3267 // A value escapes in three possible cases (this may change): 3268 // 3269 // (1) we are binding to something that is not a memory region. 3270 // (2) we are binding to a memregion that does not have stack storage 3271 // (3) we are binding to a memregion with stack storage that the store 3272 // does not understand. 3273 ProgramStateRef state = C.getState(); 3274 3275 if (loc::MemRegionVal *regionLoc = dyn_cast<loc::MemRegionVal>(&loc)) { 3276 escapes = !regionLoc->getRegion()->hasStackStorage(); 3277 3278 if (!escapes) { 3279 // To test (3), generate a new state with the binding added. If it is 3280 // the same state, then it escapes (since the store cannot represent 3281 // the binding). 3282 escapes = (state == (state->bindLoc(*regionLoc, val))); 3283 } 3284 } 3285 3286 // If our store can represent the binding and we aren't storing to something 3287 // that doesn't have local storage then just return and have the simulation 3288 // state continue as is. 3289 if (!escapes) 3290 return; 3291 3292 // Otherwise, find all symbols referenced by 'val' that we are tracking 3293 // and stop tracking them. 3294 state = state->scanReachableSymbols<StopTrackingCallback>(val).getState(); 3295 C.addTransition(state); 3296} 3297 3298ProgramStateRef RetainCountChecker::evalAssume(ProgramStateRef state, 3299 SVal Cond, 3300 bool Assumption) const { 3301 3302 // FIXME: We may add to the interface of evalAssume the list of symbols 3303 // whose assumptions have changed. For now we just iterate through the 3304 // bindings and check if any of the tracked symbols are NULL. This isn't 3305 // too bad since the number of symbols we will track in practice are 3306 // probably small and evalAssume is only called at branches and a few 3307 // other places. 3308 RefBindings B = state->get<RefBindings>(); 3309 3310 if (B.isEmpty()) 3311 return state; 3312 3313 bool changed = false; 3314 RefBindings::Factory &RefBFactory = state->get_context<RefBindings>(); 3315 3316 for (RefBindings::iterator I = B.begin(), E = B.end(); I != E; ++I) { 3317 // Check if the symbol is null (or equal to any constant). 3318 // If this is the case, stop tracking the symbol. 3319 if (state->getSymVal(I.getKey())) { 3320 changed = true; 3321 B = RefBFactory.remove(B, I.getKey()); 3322 } 3323 } 3324 3325 if (changed) 3326 state = state->set<RefBindings>(B); 3327 3328 return state; 3329} 3330 3331ProgramStateRef 3332RetainCountChecker::checkRegionChanges(ProgramStateRef state, 3333 const StoreManager::InvalidatedSymbols *invalidated, 3334 ArrayRef<const MemRegion *> ExplicitRegions, 3335 ArrayRef<const MemRegion *> Regions, 3336 const CallOrObjCMessage *Call) const { 3337 if (!invalidated) 3338 return state; 3339 3340 llvm::SmallPtrSet<SymbolRef, 8> WhitelistedSymbols; 3341 for (ArrayRef<const MemRegion *>::iterator I = ExplicitRegions.begin(), 3342 E = ExplicitRegions.end(); I != E; ++I) { 3343 if (const SymbolicRegion *SR = (*I)->StripCasts()->getAs<SymbolicRegion>()) 3344 WhitelistedSymbols.insert(SR->getSymbol()); 3345 } 3346 3347 for (StoreManager::InvalidatedSymbols::const_iterator I=invalidated->begin(), 3348 E = invalidated->end(); I!=E; ++I) { 3349 SymbolRef sym = *I; 3350 if (WhitelistedSymbols.count(sym)) 3351 continue; 3352 // Remove any existing reference-count binding. 3353 state = state->remove<RefBindings>(sym); 3354 } 3355 return state; 3356} 3357 3358//===----------------------------------------------------------------------===// 3359// Handle dead symbols and end-of-path. 3360//===----------------------------------------------------------------------===// 3361 3362std::pair<ExplodedNode *, ProgramStateRef > 3363RetainCountChecker::handleAutoreleaseCounts(ProgramStateRef state, 3364 GenericNodeBuilderRefCount Bd, 3365 ExplodedNode *Pred, 3366 CheckerContext &Ctx, 3367 SymbolRef Sym, RefVal V) const { 3368 unsigned ACnt = V.getAutoreleaseCount(); 3369 3370 // No autorelease counts? Nothing to be done. 3371 if (!ACnt) 3372 return std::make_pair(Pred, state); 3373 3374 assert(!Ctx.isObjCGCEnabled() && "Autorelease counts in GC mode?"); 3375 unsigned Cnt = V.getCount(); 3376 3377 // FIXME: Handle sending 'autorelease' to already released object. 3378 3379 if (V.getKind() == RefVal::ReturnedOwned) 3380 ++Cnt; 3381 3382 if (ACnt <= Cnt) { 3383 if (ACnt == Cnt) { 3384 V.clearCounts(); 3385 if (V.getKind() == RefVal::ReturnedOwned) 3386 V = V ^ RefVal::ReturnedNotOwned; 3387 else 3388 V = V ^ RefVal::NotOwned; 3389 } else { 3390 V.setCount(Cnt - ACnt); 3391 V.setAutoreleaseCount(0); 3392 } 3393 state = state->set<RefBindings>(Sym, V); 3394 ExplodedNode *N = Bd.MakeNode(state, Pred); 3395 if (N == 0) 3396 state = 0; 3397 return std::make_pair(N, state); 3398 } 3399 3400 // Woah! More autorelease counts then retain counts left. 3401 // Emit hard error. 3402 V = V ^ RefVal::ErrorOverAutorelease; 3403 state = state->set<RefBindings>(Sym, V); 3404 3405 if (ExplodedNode *N = Bd.MakeNode(state, Pred, true)) { 3406 SmallString<128> sbuf; 3407 llvm::raw_svector_ostream os(sbuf); 3408 os << "Object over-autoreleased: object was sent -autorelease "; 3409 if (V.getAutoreleaseCount() > 1) 3410 os << V.getAutoreleaseCount() << " times "; 3411 os << "but the object has a +" << V.getCount() << " retain count"; 3412 3413 if (!overAutorelease) 3414 overAutorelease.reset(new OverAutorelease()); 3415 3416 const LangOptions &LOpts = Ctx.getASTContext().getLangOptions(); 3417 CFRefReport *report = 3418 new CFRefReport(*overAutorelease, LOpts, /* GCEnabled = */ false, 3419 SummaryLog, N, Sym, os.str()); 3420 Ctx.EmitReport(report); 3421 } 3422 3423 return std::make_pair((ExplodedNode *)0, (ProgramStateRef )0); 3424} 3425 3426ProgramStateRef 3427RetainCountChecker::handleSymbolDeath(ProgramStateRef state, 3428 SymbolRef sid, RefVal V, 3429 SmallVectorImpl<SymbolRef> &Leaked) const { 3430 bool hasLeak = false; 3431 if (V.isOwned()) 3432 hasLeak = true; 3433 else if (V.isNotOwned() || V.isReturnedOwned()) 3434 hasLeak = (V.getCount() > 0); 3435 3436 if (!hasLeak) 3437 return state->remove<RefBindings>(sid); 3438 3439 Leaked.push_back(sid); 3440 return state->set<RefBindings>(sid, V ^ RefVal::ErrorLeak); 3441} 3442 3443ExplodedNode * 3444RetainCountChecker::processLeaks(ProgramStateRef state, 3445 SmallVectorImpl<SymbolRef> &Leaked, 3446 GenericNodeBuilderRefCount &Builder, 3447 CheckerContext &Ctx, 3448 ExplodedNode *Pred) const { 3449 if (Leaked.empty()) 3450 return Pred; 3451 3452 // Generate an intermediate node representing the leak point. 3453 ExplodedNode *N = Builder.MakeNode(state, Pred); 3454 3455 if (N) { 3456 for (SmallVectorImpl<SymbolRef>::iterator 3457 I = Leaked.begin(), E = Leaked.end(); I != E; ++I) { 3458 3459 const LangOptions &LOpts = Ctx.getASTContext().getLangOptions(); 3460 bool GCEnabled = Ctx.isObjCGCEnabled(); 3461 CFRefBug *BT = Pred ? getLeakWithinFunctionBug(LOpts, GCEnabled) 3462 : getLeakAtReturnBug(LOpts, GCEnabled); 3463 assert(BT && "BugType not initialized."); 3464 3465 CFRefLeakReport *report = new CFRefLeakReport(*BT, LOpts, GCEnabled, 3466 SummaryLog, N, *I, Ctx); 3467 Ctx.EmitReport(report); 3468 } 3469 } 3470 3471 return N; 3472} 3473 3474void RetainCountChecker::checkEndPath(CheckerContext &Ctx) const { 3475 ProgramStateRef state = Ctx.getState(); 3476 GenericNodeBuilderRefCount Bd(Ctx); 3477 RefBindings B = state->get<RefBindings>(); 3478 ExplodedNode *Pred = Ctx.getPredecessor(); 3479 3480 for (RefBindings::iterator I = B.begin(), E = B.end(); I != E; ++I) { 3481 llvm::tie(Pred, state) = handleAutoreleaseCounts(state, Bd, Pred, Ctx, 3482 I->first, I->second); 3483 if (!state) 3484 return; 3485 } 3486 3487 // If the current LocationContext has a parent, don't check for leaks. 3488 // We will do that later. 3489 // FIXME: we should instead check for imblances of the retain/releases, 3490 // and suggest annotations. 3491 if (Ctx.getLocationContext()->getParent()) 3492 return; 3493 3494 B = state->get<RefBindings>(); 3495 SmallVector<SymbolRef, 10> Leaked; 3496 3497 for (RefBindings::iterator I = B.begin(), E = B.end(); I != E; ++I) 3498 state = handleSymbolDeath(state, I->first, I->second, Leaked); 3499 3500 processLeaks(state, Leaked, Bd, Ctx, Pred); 3501} 3502 3503const ProgramPointTag * 3504RetainCountChecker::getDeadSymbolTag(SymbolRef sym) const { 3505 const SimpleProgramPointTag *&tag = DeadSymbolTags[sym]; 3506 if (!tag) { 3507 SmallString<64> buf; 3508 llvm::raw_svector_ostream out(buf); 3509 out << "RetainCountChecker : Dead Symbol : "; 3510 sym->dumpToStream(out); 3511 tag = new SimpleProgramPointTag(out.str()); 3512 } 3513 return tag; 3514} 3515 3516void RetainCountChecker::checkDeadSymbols(SymbolReaper &SymReaper, 3517 CheckerContext &C) const { 3518 ExplodedNode *Pred = C.getPredecessor(); 3519 3520 ProgramStateRef state = C.getState(); 3521 RefBindings B = state->get<RefBindings>(); 3522 3523 // Update counts from autorelease pools 3524 for (SymbolReaper::dead_iterator I = SymReaper.dead_begin(), 3525 E = SymReaper.dead_end(); I != E; ++I) { 3526 SymbolRef Sym = *I; 3527 if (const RefVal *T = B.lookup(Sym)){ 3528 // Use the symbol as the tag. 3529 // FIXME: This might not be as unique as we would like. 3530 GenericNodeBuilderRefCount Bd(C, getDeadSymbolTag(Sym)); 3531 llvm::tie(Pred, state) = handleAutoreleaseCounts(state, Bd, Pred, C, 3532 Sym, *T); 3533 if (!state) 3534 return; 3535 } 3536 } 3537 3538 B = state->get<RefBindings>(); 3539 SmallVector<SymbolRef, 10> Leaked; 3540 3541 for (SymbolReaper::dead_iterator I = SymReaper.dead_begin(), 3542 E = SymReaper.dead_end(); I != E; ++I) { 3543 if (const RefVal *T = B.lookup(*I)) 3544 state = handleSymbolDeath(state, *I, *T, Leaked); 3545 } 3546 3547 { 3548 GenericNodeBuilderRefCount Bd(C, this); 3549 Pred = processLeaks(state, Leaked, Bd, C, Pred); 3550 } 3551 3552 // Did we cache out? 3553 if (!Pred) 3554 return; 3555 3556 // Now generate a new node that nukes the old bindings. 3557 RefBindings::Factory &F = state->get_context<RefBindings>(); 3558 3559 for (SymbolReaper::dead_iterator I = SymReaper.dead_begin(), 3560 E = SymReaper.dead_end(); I != E; ++I) 3561 B = F.remove(B, *I); 3562 3563 state = state->set<RefBindings>(B); 3564 C.addTransition(state, Pred); 3565} 3566 3567//===----------------------------------------------------------------------===// 3568// Debug printing of refcount bindings and autorelease pools. 3569//===----------------------------------------------------------------------===// 3570 3571static void PrintPool(raw_ostream &Out, SymbolRef Sym, 3572 ProgramStateRef State) { 3573 Out << ' '; 3574 if (Sym) 3575 Sym->dumpToStream(Out); 3576 else 3577 Out << "<pool>"; 3578 Out << ":{"; 3579 3580 // Get the contents of the pool. 3581 if (const ARCounts *Cnts = State->get<AutoreleasePoolContents>(Sym)) 3582 for (ARCounts::iterator I = Cnts->begin(), E = Cnts->end(); I != E; ++I) 3583 Out << '(' << I.getKey() << ',' << I.getData() << ')'; 3584 3585 Out << '}'; 3586} 3587 3588static bool UsesAutorelease(ProgramStateRef state) { 3589 // A state uses autorelease if it allocated an autorelease pool or if it has 3590 // objects in the caller's autorelease pool. 3591 return !state->get<AutoreleaseStack>().isEmpty() || 3592 state->get<AutoreleasePoolContents>(SymbolRef()); 3593} 3594 3595void RetainCountChecker::printState(raw_ostream &Out, ProgramStateRef State, 3596 const char *NL, const char *Sep) const { 3597 3598 RefBindings B = State->get<RefBindings>(); 3599 3600 if (!B.isEmpty()) 3601 Out << Sep << NL; 3602 3603 for (RefBindings::iterator I = B.begin(), E = B.end(); I != E; ++I) { 3604 Out << I->first << " : "; 3605 I->second.print(Out); 3606 Out << NL; 3607 } 3608 3609 // Print the autorelease stack. 3610 if (UsesAutorelease(State)) { 3611 Out << Sep << NL << "AR pool stack:"; 3612 ARStack Stack = State->get<AutoreleaseStack>(); 3613 3614 PrintPool(Out, SymbolRef(), State); // Print the caller's pool. 3615 for (ARStack::iterator I = Stack.begin(), E = Stack.end(); I != E; ++I) 3616 PrintPool(Out, *I, State); 3617 3618 Out << NL; 3619 } 3620} 3621 3622//===----------------------------------------------------------------------===// 3623// Checker registration. 3624//===----------------------------------------------------------------------===// 3625 3626void ento::registerRetainCountChecker(CheckerManager &Mgr) { 3627 Mgr.registerChecker<RetainCountChecker>(); 3628} 3629 3630