RetainCountChecker.cpp revision b805c8ff133ef0c62df032fa711d6b13c5afd7f4
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/STLExtras.h" 35#include "llvm/ADT/StringExtras.h" 36#include <cstdarg> 37 38using namespace clang; 39using namespace ento; 40using llvm::StrInStrNoCase; 41 42namespace { 43/// Wrapper around different kinds of node builder, so that helper functions 44/// can have a common interface. 45class GenericNodeBuilderRefCount { 46 CheckerContext *C; 47 const ProgramPointTag *tag; 48public: 49 GenericNodeBuilderRefCount(CheckerContext &c, 50 const ProgramPointTag *t = 0) 51 : C(&c), tag(t){} 52 53 ExplodedNode *MakeNode(const ProgramState *state, ExplodedNode *Pred, 54 bool MarkAsSink = false) { 55 return C->addTransition(state, Pred, tag, MarkAsSink); 56 } 57}; 58} // end anonymous namespace 59 60//===----------------------------------------------------------------------===// 61// Primitives used for constructing summaries for function/method calls. 62//===----------------------------------------------------------------------===// 63 64/// ArgEffect is used to summarize a function/method call's effect on a 65/// particular argument. 66enum ArgEffect { DoNothing, Autorelease, Dealloc, DecRef, DecRefMsg, 67 DecRefBridgedTransfered, 68 IncRefMsg, IncRef, MakeCollectable, MayEscape, 69 NewAutoreleasePool, SelfOwn, StopTracking }; 70 71namespace llvm { 72template <> struct FoldingSetTrait<ArgEffect> { 73static inline void Profile(const ArgEffect X, FoldingSetNodeID& ID) { 74 ID.AddInteger((unsigned) X); 75} 76}; 77} // end llvm namespace 78 79/// ArgEffects summarizes the effects of a function/method call on all of 80/// its arguments. 81typedef llvm::ImmutableMap<unsigned,ArgEffect> ArgEffects; 82 83namespace { 84 85/// RetEffect is used to summarize a function/method call's behavior with 86/// respect to its return value. 87class RetEffect { 88public: 89 enum Kind { NoRet, OwnedSymbol, OwnedAllocatedSymbol, 90 NotOwnedSymbol, GCNotOwnedSymbol, ARCNotOwnedSymbol, 91 OwnedWhenTrackedReceiver }; 92 93 enum ObjKind { CF, ObjC, AnyObj }; 94 95private: 96 Kind K; 97 ObjKind O; 98 99 RetEffect(Kind k, ObjKind o = AnyObj) : K(k), O(o) {} 100 101public: 102 Kind getKind() const { return K; } 103 104 ObjKind getObjKind() const { return O; } 105 106 bool isOwned() const { 107 return K == OwnedSymbol || K == OwnedAllocatedSymbol || 108 K == OwnedWhenTrackedReceiver; 109 } 110 111 bool operator==(const RetEffect &Other) const { 112 return K == Other.K && O == Other.O; 113 } 114 115 static RetEffect MakeOwnedWhenTrackedReceiver() { 116 return RetEffect(OwnedWhenTrackedReceiver, ObjC); 117 } 118 119 static RetEffect MakeOwned(ObjKind o, bool isAllocated = false) { 120 return RetEffect(isAllocated ? OwnedAllocatedSymbol : OwnedSymbol, o); 121 } 122 static RetEffect MakeNotOwned(ObjKind o) { 123 return RetEffect(NotOwnedSymbol, o); 124 } 125 static RetEffect MakeGCNotOwned() { 126 return RetEffect(GCNotOwnedSymbol, ObjC); 127 } 128 static RetEffect MakeARCNotOwned() { 129 return RetEffect(ARCNotOwnedSymbol, ObjC); 130 } 131 static RetEffect MakeNoRet() { 132 return RetEffect(NoRet); 133 } 134}; 135 136//===----------------------------------------------------------------------===// 137// Reference-counting logic (typestate + counts). 138//===----------------------------------------------------------------------===// 139 140class RefVal { 141public: 142 enum Kind { 143 Owned = 0, // Owning reference. 144 NotOwned, // Reference is not owned by still valid (not freed). 145 Released, // Object has been released. 146 ReturnedOwned, // Returned object passes ownership to caller. 147 ReturnedNotOwned, // Return object does not pass ownership to caller. 148 ERROR_START, 149 ErrorDeallocNotOwned, // -dealloc called on non-owned object. 150 ErrorDeallocGC, // Calling -dealloc with GC enabled. 151 ErrorUseAfterRelease, // Object used after released. 152 ErrorReleaseNotOwned, // Release of an object that was not owned. 153 ERROR_LEAK_START, 154 ErrorLeak, // A memory leak due to excessive reference counts. 155 ErrorLeakReturned, // A memory leak due to the returning method not having 156 // the correct naming conventions. 157 ErrorGCLeakReturned, 158 ErrorOverAutorelease, 159 ErrorReturnedNotOwned 160 }; 161 162private: 163 Kind kind; 164 RetEffect::ObjKind okind; 165 unsigned Cnt; 166 unsigned ACnt; 167 QualType T; 168 169 RefVal(Kind k, RetEffect::ObjKind o, unsigned cnt, unsigned acnt, QualType t) 170 : kind(k), okind(o), Cnt(cnt), ACnt(acnt), T(t) {} 171 172public: 173 Kind getKind() const { return kind; } 174 175 RetEffect::ObjKind getObjKind() const { return okind; } 176 177 unsigned getCount() const { return Cnt; } 178 unsigned getAutoreleaseCount() const { return ACnt; } 179 unsigned getCombinedCounts() const { return Cnt + ACnt; } 180 void clearCounts() { Cnt = 0; ACnt = 0; } 181 void setCount(unsigned i) { Cnt = i; } 182 void setAutoreleaseCount(unsigned i) { ACnt = i; } 183 184 QualType getType() const { return T; } 185 186 bool isOwned() const { 187 return getKind() == Owned; 188 } 189 190 bool isNotOwned() const { 191 return getKind() == NotOwned; 192 } 193 194 bool isReturnedOwned() const { 195 return getKind() == ReturnedOwned; 196 } 197 198 bool isReturnedNotOwned() const { 199 return getKind() == ReturnedNotOwned; 200 } 201 202 static RefVal makeOwned(RetEffect::ObjKind o, QualType t, 203 unsigned Count = 1) { 204 return RefVal(Owned, o, Count, 0, t); 205 } 206 207 static RefVal makeNotOwned(RetEffect::ObjKind o, QualType t, 208 unsigned Count = 0) { 209 return RefVal(NotOwned, o, Count, 0, t); 210 } 211 212 // Comparison, profiling, and pretty-printing. 213 214 bool operator==(const RefVal& X) const { 215 return kind == X.kind && Cnt == X.Cnt && T == X.T && ACnt == X.ACnt; 216 } 217 218 RefVal operator-(size_t i) const { 219 return RefVal(getKind(), getObjKind(), getCount() - i, 220 getAutoreleaseCount(), getType()); 221 } 222 223 RefVal operator+(size_t i) const { 224 return RefVal(getKind(), getObjKind(), getCount() + i, 225 getAutoreleaseCount(), getType()); 226 } 227 228 RefVal operator^(Kind k) const { 229 return RefVal(k, getObjKind(), getCount(), getAutoreleaseCount(), 230 getType()); 231 } 232 233 RefVal autorelease() const { 234 return RefVal(getKind(), getObjKind(), getCount(), getAutoreleaseCount()+1, 235 getType()); 236 } 237 238 void Profile(llvm::FoldingSetNodeID& ID) const { 239 ID.AddInteger((unsigned) kind); 240 ID.AddInteger(Cnt); 241 ID.AddInteger(ACnt); 242 ID.Add(T); 243 } 244 245 void print(raw_ostream &Out) const; 246}; 247 248void RefVal::print(raw_ostream &Out) const { 249 if (!T.isNull()) 250 Out << "Tracked " << T.getAsString() << '/'; 251 252 switch (getKind()) { 253 default: llvm_unreachable("Invalid RefVal kind"); 254 case Owned: { 255 Out << "Owned"; 256 unsigned cnt = getCount(); 257 if (cnt) Out << " (+ " << cnt << ")"; 258 break; 259 } 260 261 case NotOwned: { 262 Out << "NotOwned"; 263 unsigned cnt = getCount(); 264 if (cnt) Out << " (+ " << cnt << ")"; 265 break; 266 } 267 268 case ReturnedOwned: { 269 Out << "ReturnedOwned"; 270 unsigned cnt = getCount(); 271 if (cnt) Out << " (+ " << cnt << ")"; 272 break; 273 } 274 275 case ReturnedNotOwned: { 276 Out << "ReturnedNotOwned"; 277 unsigned cnt = getCount(); 278 if (cnt) Out << " (+ " << cnt << ")"; 279 break; 280 } 281 282 case Released: 283 Out << "Released"; 284 break; 285 286 case ErrorDeallocGC: 287 Out << "-dealloc (GC)"; 288 break; 289 290 case ErrorDeallocNotOwned: 291 Out << "-dealloc (not-owned)"; 292 break; 293 294 case ErrorLeak: 295 Out << "Leaked"; 296 break; 297 298 case ErrorLeakReturned: 299 Out << "Leaked (Bad naming)"; 300 break; 301 302 case ErrorGCLeakReturned: 303 Out << "Leaked (GC-ed at return)"; 304 break; 305 306 case ErrorUseAfterRelease: 307 Out << "Use-After-Release [ERROR]"; 308 break; 309 310 case ErrorReleaseNotOwned: 311 Out << "Release of Not-Owned [ERROR]"; 312 break; 313 314 case RefVal::ErrorOverAutorelease: 315 Out << "Over autoreleased"; 316 break; 317 318 case RefVal::ErrorReturnedNotOwned: 319 Out << "Non-owned object returned instead of owned"; 320 break; 321 } 322 323 if (ACnt) { 324 Out << " [ARC +" << ACnt << ']'; 325 } 326} 327} //end anonymous namespace 328 329//===----------------------------------------------------------------------===// 330// RefBindings - State used to track object reference counts. 331//===----------------------------------------------------------------------===// 332 333typedef llvm::ImmutableMap<SymbolRef, RefVal> RefBindings; 334 335namespace clang { 336namespace ento { 337template<> 338struct ProgramStateTrait<RefBindings> 339 : public ProgramStatePartialTrait<RefBindings> { 340 static void *GDMIndex() { 341 static int RefBIndex = 0; 342 return &RefBIndex; 343 } 344}; 345} 346} 347 348//===----------------------------------------------------------------------===// 349// Function/Method behavior summaries. 350//===----------------------------------------------------------------------===// 351 352namespace { 353class RetainSummary { 354 /// Args - an ordered vector of (index, ArgEffect) pairs, where index 355 /// specifies the argument (starting from 0). This can be sparsely 356 /// populated; arguments with no entry in Args use 'DefaultArgEffect'. 357 ArgEffects Args; 358 359 /// DefaultArgEffect - The default ArgEffect to apply to arguments that 360 /// do not have an entry in Args. 361 ArgEffect DefaultArgEffect; 362 363 /// Receiver - If this summary applies to an Objective-C message expression, 364 /// this is the effect applied to the state of the receiver. 365 ArgEffect Receiver; 366 367 /// Ret - The effect on the return value. Used to indicate if the 368 /// function/method call returns a new tracked symbol. 369 RetEffect Ret; 370 371public: 372 RetainSummary(ArgEffects A, RetEffect R, ArgEffect defaultEff, 373 ArgEffect ReceiverEff) 374 : Args(A), DefaultArgEffect(defaultEff), Receiver(ReceiverEff), Ret(R) {} 375 376 /// getArg - Return the argument effect on the argument specified by 377 /// idx (starting from 0). 378 ArgEffect getArg(unsigned idx) const { 379 if (const ArgEffect *AE = Args.lookup(idx)) 380 return *AE; 381 382 return DefaultArgEffect; 383 } 384 385 void addArg(ArgEffects::Factory &af, unsigned idx, ArgEffect e) { 386 Args = af.add(Args, idx, e); 387 } 388 389 /// setDefaultArgEffect - Set the default argument effect. 390 void setDefaultArgEffect(ArgEffect E) { 391 DefaultArgEffect = E; 392 } 393 394 /// getRetEffect - Returns the effect on the return value of the call. 395 RetEffect getRetEffect() const { return Ret; } 396 397 /// setRetEffect - Set the effect of the return value of the call. 398 void setRetEffect(RetEffect E) { Ret = E; } 399 400 401 /// Sets the effect on the receiver of the message. 402 void setReceiverEffect(ArgEffect e) { Receiver = e; } 403 404 /// getReceiverEffect - Returns the effect on the receiver of the call. 405 /// This is only meaningful if the summary applies to an ObjCMessageExpr*. 406 ArgEffect getReceiverEffect() const { return Receiver; } 407 408 /// Test if two retain summaries are identical. Note that merely equivalent 409 /// summaries are not necessarily identical (for example, if an explicit 410 /// argument effect matches the default effect). 411 bool operator==(const RetainSummary &Other) const { 412 return Args == Other.Args && DefaultArgEffect == Other.DefaultArgEffect && 413 Receiver == Other.Receiver && Ret == Other.Ret; 414 } 415}; 416} // end anonymous namespace 417 418//===----------------------------------------------------------------------===// 419// Data structures for constructing summaries. 420//===----------------------------------------------------------------------===// 421 422namespace { 423class ObjCSummaryKey { 424 IdentifierInfo* II; 425 Selector S; 426public: 427 ObjCSummaryKey(IdentifierInfo* ii, Selector s) 428 : II(ii), S(s) {} 429 430 ObjCSummaryKey(const ObjCInterfaceDecl *d, Selector s) 431 : II(d ? d->getIdentifier() : 0), S(s) {} 432 433 ObjCSummaryKey(const ObjCInterfaceDecl *d, IdentifierInfo *ii, Selector s) 434 : II(d ? d->getIdentifier() : ii), S(s) {} 435 436 ObjCSummaryKey(Selector s) 437 : II(0), S(s) {} 438 439 IdentifierInfo* getIdentifier() const { return II; } 440 Selector getSelector() const { return S; } 441}; 442} 443 444namespace llvm { 445template <> struct DenseMapInfo<ObjCSummaryKey> { 446 static inline ObjCSummaryKey getEmptyKey() { 447 return ObjCSummaryKey(DenseMapInfo<IdentifierInfo*>::getEmptyKey(), 448 DenseMapInfo<Selector>::getEmptyKey()); 449 } 450 451 static inline ObjCSummaryKey getTombstoneKey() { 452 return ObjCSummaryKey(DenseMapInfo<IdentifierInfo*>::getTombstoneKey(), 453 DenseMapInfo<Selector>::getTombstoneKey()); 454 } 455 456 static unsigned getHashValue(const ObjCSummaryKey &V) { 457 return (DenseMapInfo<IdentifierInfo*>::getHashValue(V.getIdentifier()) 458 & 0x88888888) 459 | (DenseMapInfo<Selector>::getHashValue(V.getSelector()) 460 & 0x55555555); 461 } 462 463 static bool isEqual(const ObjCSummaryKey& LHS, const ObjCSummaryKey& RHS) { 464 return DenseMapInfo<IdentifierInfo*>::isEqual(LHS.getIdentifier(), 465 RHS.getIdentifier()) && 466 DenseMapInfo<Selector>::isEqual(LHS.getSelector(), 467 RHS.getSelector()); 468 } 469 470}; 471template <> 472struct isPodLike<ObjCSummaryKey> { static const bool value = true; }; 473} // end llvm namespace 474 475namespace { 476class ObjCSummaryCache { 477 typedef llvm::DenseMap<ObjCSummaryKey, const RetainSummary *> MapTy; 478 MapTy M; 479public: 480 ObjCSummaryCache() {} 481 482 const RetainSummary * find(const ObjCInterfaceDecl *D, IdentifierInfo *ClsName, 483 Selector S) { 484 // Lookup the method using the decl for the class @interface. If we 485 // have no decl, lookup using the class name. 486 return D ? find(D, S) : find(ClsName, S); 487 } 488 489 const RetainSummary * find(const ObjCInterfaceDecl *D, Selector S) { 490 // Do a lookup with the (D,S) pair. If we find a match return 491 // the iterator. 492 ObjCSummaryKey K(D, S); 493 MapTy::iterator I = M.find(K); 494 495 if (I != M.end() || !D) 496 return I->second; 497 498 // Walk the super chain. If we find a hit with a parent, we'll end 499 // up returning that summary. We actually allow that key (null,S), as 500 // we cache summaries for the null ObjCInterfaceDecl* to allow us to 501 // generate initial summaries without having to worry about NSObject 502 // being declared. 503 // FIXME: We may change this at some point. 504 for (ObjCInterfaceDecl *C=D->getSuperClass() ;; C=C->getSuperClass()) { 505 if ((I = M.find(ObjCSummaryKey(C, S))) != M.end()) 506 break; 507 508 if (!C) 509 return NULL; 510 } 511 512 // Cache the summary with original key to make the next lookup faster 513 // and return the iterator. 514 const RetainSummary *Summ = I->second; 515 M[K] = Summ; 516 return Summ; 517 } 518 519 const RetainSummary * find(IdentifierInfo* II, Selector S) { 520 // FIXME: Class method lookup. Right now we dont' have a good way 521 // of going between IdentifierInfo* and the class hierarchy. 522 MapTy::iterator I = M.find(ObjCSummaryKey(II, S)); 523 524 if (I == M.end()) 525 I = M.find(ObjCSummaryKey(S)); 526 527 return I == M.end() ? NULL : I->second; 528 } 529 530 const RetainSummary *& operator[](ObjCSummaryKey K) { 531 return M[K]; 532 } 533 534 const RetainSummary *& operator[](Selector S) { 535 return M[ ObjCSummaryKey(S) ]; 536 } 537}; 538} // end anonymous namespace 539 540//===----------------------------------------------------------------------===// 541// Data structures for managing collections of summaries. 542//===----------------------------------------------------------------------===// 543 544namespace { 545class RetainSummaryManager { 546 547 //==-----------------------------------------------------------------==// 548 // Typedefs. 549 //==-----------------------------------------------------------------==// 550 551 typedef llvm::DenseMap<const FunctionDecl*, const RetainSummary *> 552 FuncSummariesTy; 553 554 typedef ObjCSummaryCache ObjCMethodSummariesTy; 555 556 //==-----------------------------------------------------------------==// 557 // Data. 558 //==-----------------------------------------------------------------==// 559 560 /// Ctx - The ASTContext object for the analyzed ASTs. 561 ASTContext &Ctx; 562 563 /// GCEnabled - Records whether or not the analyzed code runs in GC mode. 564 const bool GCEnabled; 565 566 /// Records whether or not the analyzed code runs in ARC mode. 567 const bool ARCEnabled; 568 569 /// FuncSummaries - A map from FunctionDecls to summaries. 570 FuncSummariesTy FuncSummaries; 571 572 /// ObjCClassMethodSummaries - A map from selectors (for instance methods) 573 /// to summaries. 574 ObjCMethodSummariesTy ObjCClassMethodSummaries; 575 576 /// ObjCMethodSummaries - A map from selectors to summaries. 577 ObjCMethodSummariesTy ObjCMethodSummaries; 578 579 /// BPAlloc - A BumpPtrAllocator used for allocating summaries, ArgEffects, 580 /// and all other data used by the checker. 581 llvm::BumpPtrAllocator BPAlloc; 582 583 /// AF - A factory for ArgEffects objects. 584 ArgEffects::Factory AF; 585 586 /// ScratchArgs - A holding buffer for construct ArgEffects. 587 ArgEffects ScratchArgs; 588 589 /// ObjCAllocRetE - Default return effect for methods returning Objective-C 590 /// objects. 591 RetEffect ObjCAllocRetE; 592 593 /// ObjCInitRetE - Default return effect for init methods returning 594 /// Objective-C objects. 595 RetEffect ObjCInitRetE; 596 597 RetainSummary DefaultSummary; 598 const RetainSummary *StopSummary; 599 600 //==-----------------------------------------------------------------==// 601 // Methods. 602 //==-----------------------------------------------------------------==// 603 604 /// getArgEffects - Returns a persistent ArgEffects object based on the 605 /// data in ScratchArgs. 606 ArgEffects getArgEffects(); 607 608 enum UnaryFuncKind { cfretain, cfrelease, cfmakecollectable }; 609 610public: 611 RetEffect getObjAllocRetEffect() const { return ObjCAllocRetE; } 612 613 const RetainSummary *getDefaultSummary() { 614 return &DefaultSummary; 615 } 616 617 const RetainSummary * getUnarySummary(const FunctionType* FT, 618 UnaryFuncKind func); 619 620 const RetainSummary * getCFSummaryCreateRule(const FunctionDecl *FD); 621 const RetainSummary * getCFSummaryGetRule(const FunctionDecl *FD); 622 const RetainSummary * getCFCreateGetRuleSummary(const FunctionDecl *FD); 623 624 const RetainSummary * getPersistentSummary(ArgEffects AE, RetEffect RetEff, 625 ArgEffect ReceiverEff = DoNothing, 626 ArgEffect DefaultEff = MayEscape); 627 628 const RetainSummary * getPersistentSummary(RetEffect RE, 629 ArgEffect ReceiverEff = DoNothing, 630 ArgEffect DefaultEff = MayEscape) { 631 return getPersistentSummary(getArgEffects(), RE, ReceiverEff, DefaultEff); 632 } 633 634 const RetainSummary *getPersistentStopSummary() { 635 if (StopSummary) 636 return StopSummary; 637 638 StopSummary = getPersistentSummary(RetEffect::MakeNoRet(), 639 StopTracking, StopTracking); 640 641 return StopSummary; 642 } 643 644 const RetainSummary *getInitMethodSummary(QualType RetTy); 645 646 void InitializeClassMethodSummaries(); 647 void InitializeMethodSummaries(); 648private: 649 void addNSObjectClsMethSummary(Selector S, const RetainSummary *Summ) { 650 ObjCClassMethodSummaries[S] = Summ; 651 } 652 653 void addNSObjectMethSummary(Selector S, const RetainSummary *Summ) { 654 ObjCMethodSummaries[S] = Summ; 655 } 656 657 void addClassMethSummary(const char* Cls, const char* nullaryName, 658 const RetainSummary *Summ) { 659 IdentifierInfo* ClsII = &Ctx.Idents.get(Cls); 660 Selector S = GetNullarySelector(nullaryName, Ctx); 661 ObjCClassMethodSummaries[ObjCSummaryKey(ClsII, S)] = Summ; 662 } 663 664 void addInstMethSummary(const char* Cls, const char* nullaryName, 665 const RetainSummary *Summ) { 666 IdentifierInfo* ClsII = &Ctx.Idents.get(Cls); 667 Selector S = GetNullarySelector(nullaryName, Ctx); 668 ObjCMethodSummaries[ObjCSummaryKey(ClsII, S)] = Summ; 669 } 670 671 Selector generateSelector(va_list argp) { 672 SmallVector<IdentifierInfo*, 10> II; 673 674 while (const char* s = va_arg(argp, const char*)) 675 II.push_back(&Ctx.Idents.get(s)); 676 677 return Ctx.Selectors.getSelector(II.size(), &II[0]); 678 } 679 680 void addMethodSummary(IdentifierInfo *ClsII, ObjCMethodSummariesTy& Summaries, 681 const RetainSummary * Summ, va_list argp) { 682 Selector S = generateSelector(argp); 683 Summaries[ObjCSummaryKey(ClsII, S)] = Summ; 684 } 685 686 void addInstMethSummary(const char* Cls, const RetainSummary * Summ, ...) { 687 va_list argp; 688 va_start(argp, Summ); 689 addMethodSummary(&Ctx.Idents.get(Cls), ObjCMethodSummaries, Summ, argp); 690 va_end(argp); 691 } 692 693 void addClsMethSummary(const char* Cls, const RetainSummary * Summ, ...) { 694 va_list argp; 695 va_start(argp, Summ); 696 addMethodSummary(&Ctx.Idents.get(Cls),ObjCClassMethodSummaries, Summ, argp); 697 va_end(argp); 698 } 699 700 void addClsMethSummary(IdentifierInfo *II, const RetainSummary * Summ, ...) { 701 va_list argp; 702 va_start(argp, Summ); 703 addMethodSummary(II, ObjCClassMethodSummaries, Summ, argp); 704 va_end(argp); 705 } 706 707public: 708 709 RetainSummaryManager(ASTContext &ctx, bool gcenabled, bool usesARC) 710 : Ctx(ctx), 711 GCEnabled(gcenabled), 712 ARCEnabled(usesARC), 713 AF(BPAlloc), ScratchArgs(AF.getEmptyMap()), 714 ObjCAllocRetE(gcenabled 715 ? RetEffect::MakeGCNotOwned() 716 : (usesARC ? RetEffect::MakeARCNotOwned() 717 : RetEffect::MakeOwned(RetEffect::ObjC, true))), 718 ObjCInitRetE(gcenabled 719 ? RetEffect::MakeGCNotOwned() 720 : (usesARC ? RetEffect::MakeARCNotOwned() 721 : RetEffect::MakeOwnedWhenTrackedReceiver())), 722 DefaultSummary(AF.getEmptyMap() /* per-argument effects (none) */, 723 RetEffect::MakeNoRet() /* return effect */, 724 MayEscape, /* default argument effect */ 725 DoNothing /* receiver effect */), 726 StopSummary(0) { 727 728 InitializeClassMethodSummaries(); 729 InitializeMethodSummaries(); 730 } 731 732 const RetainSummary * getSummary(const FunctionDecl *FD); 733 734 const RetainSummary *getInstanceMethodSummary(const ObjCMessage &msg, 735 const ProgramState *state, 736 const LocationContext *LC); 737 738 const RetainSummary * getInstanceMethodSummary(const ObjCMessage &msg, 739 const ObjCInterfaceDecl *ID) { 740 return getInstanceMethodSummary(msg.getSelector(), 0, 741 ID, msg.getMethodDecl(), msg.getType(Ctx)); 742 } 743 744 const RetainSummary * getInstanceMethodSummary(Selector S, 745 IdentifierInfo *ClsName, 746 const ObjCInterfaceDecl *ID, 747 const ObjCMethodDecl *MD, 748 QualType RetTy); 749 750 const RetainSummary *getClassMethodSummary(Selector S, 751 IdentifierInfo *ClsName, 752 const ObjCInterfaceDecl *ID, 753 const ObjCMethodDecl *MD, 754 QualType RetTy); 755 756 const RetainSummary *getClassMethodSummary(const ObjCMessage &msg) { 757 const ObjCInterfaceDecl *Class = 0; 758 if (!msg.isInstanceMessage()) 759 Class = msg.getReceiverInterface(); 760 761 return getClassMethodSummary(msg.getSelector(), 762 Class? Class->getIdentifier() : 0, 763 Class, 764 msg.getMethodDecl(), msg.getType(Ctx)); 765 } 766 767 /// getMethodSummary - This version of getMethodSummary is used to query 768 /// the summary for the current method being analyzed. 769 const RetainSummary *getMethodSummary(const ObjCMethodDecl *MD) { 770 // FIXME: Eventually this should be unneeded. 771 const ObjCInterfaceDecl *ID = MD->getClassInterface(); 772 Selector S = MD->getSelector(); 773 IdentifierInfo *ClsName = ID->getIdentifier(); 774 QualType ResultTy = MD->getResultType(); 775 776 if (MD->isInstanceMethod()) 777 return getInstanceMethodSummary(S, ClsName, ID, MD, ResultTy); 778 else 779 return getClassMethodSummary(S, ClsName, ID, MD, ResultTy); 780 } 781 782 const RetainSummary * getCommonMethodSummary(const ObjCMethodDecl *MD, 783 Selector S, QualType RetTy); 784 785 void updateSummaryFromAnnotations(const RetainSummary *&Summ, 786 const ObjCMethodDecl *MD); 787 788 void updateSummaryFromAnnotations(const RetainSummary *&Summ, 789 const FunctionDecl *FD); 790 791 bool isGCEnabled() const { return GCEnabled; } 792 793 bool isARCEnabled() const { return ARCEnabled; } 794 795 bool isARCorGCEnabled() const { return GCEnabled || ARCEnabled; } 796 797 const RetainSummary *copySummary(const RetainSummary *OldSumm) { 798 RetainSummary *Summ = (RetainSummary *) BPAlloc.Allocate<RetainSummary>(); 799 new (Summ) RetainSummary(*OldSumm); 800 return Summ; 801 } 802}; 803 804// Used to avoid allocating long-term (BPAlloc'd) memory for default retain 805// summaries. If a function or method looks like it has a default summary, but 806// it has annotations, the annotations are added to the stack-based template 807// and then copied into managed memory. 808class RetainSummaryTemplate { 809 RetainSummaryManager &Manager; 810 const RetainSummary *&RealSummary; 811 const RetainSummary *BaseSummary; 812 RetainSummary ScratchSummary; 813 bool Accessed; 814public: 815 RetainSummaryTemplate(const RetainSummary *&real, const RetainSummary &base, 816 RetainSummaryManager &manager) 817 : Manager(manager), 818 RealSummary(real), 819 BaseSummary(&base), 820 ScratchSummary(base), 821 Accessed(false) {} 822 823 ~RetainSummaryTemplate() { 824 if (Accessed) 825 RealSummary = Manager.copySummary(&ScratchSummary); 826 else if (!RealSummary) 827 RealSummary = BaseSummary; 828 } 829 830 RetainSummary &operator*() { 831 Accessed = true; 832 return ScratchSummary; 833 } 834 835 RetainSummary *operator->() { 836 Accessed = true; 837 return &ScratchSummary; 838 } 839}; 840 841} // end anonymous namespace 842 843//===----------------------------------------------------------------------===// 844// Implementation of checker data structures. 845//===----------------------------------------------------------------------===// 846 847ArgEffects RetainSummaryManager::getArgEffects() { 848 ArgEffects AE = ScratchArgs; 849 ScratchArgs = AF.getEmptyMap(); 850 return AE; 851} 852 853const RetainSummary * 854RetainSummaryManager::getPersistentSummary(ArgEffects AE, RetEffect RetEff, 855 ArgEffect ReceiverEff, 856 ArgEffect DefaultEff) { 857 // Create the summary and return it. 858 RetainSummary *Summ = (RetainSummary *) BPAlloc.Allocate<RetainSummary>(); 859 new (Summ) RetainSummary(AE, RetEff, DefaultEff, ReceiverEff); 860 return Summ; 861} 862 863//===----------------------------------------------------------------------===// 864// Summary creation for functions (largely uses of Core Foundation). 865//===----------------------------------------------------------------------===// 866 867static bool isRetain(const FunctionDecl *FD, StringRef FName) { 868 return FName.endswith("Retain"); 869} 870 871static bool isRelease(const FunctionDecl *FD, StringRef FName) { 872 return FName.endswith("Release"); 873} 874 875static bool isMakeCollectable(const FunctionDecl *FD, StringRef FName) { 876 // FIXME: Remove FunctionDecl parameter. 877 // FIXME: Is it really okay if MakeCollectable isn't a suffix? 878 return FName.find("MakeCollectable") != StringRef::npos; 879} 880 881const RetainSummary * RetainSummaryManager::getSummary(const FunctionDecl *FD) { 882 // Look up a summary in our cache of FunctionDecls -> Summaries. 883 FuncSummariesTy::iterator I = FuncSummaries.find(FD); 884 if (I != FuncSummaries.end()) 885 return I->second; 886 887 // No summary? Generate one. 888 const RetainSummary *S = 0; 889 890 do { 891 // We generate "stop" summaries for implicitly defined functions. 892 if (FD->isImplicit()) { 893 S = getPersistentStopSummary(); 894 break; 895 } 896 // For C++ methods, generate an implicit "stop" summary as well. We 897 // can relax this once we have a clear policy for C++ methods and 898 // ownership attributes. 899 if (isa<CXXMethodDecl>(FD)) { 900 S = getPersistentStopSummary(); 901 break; 902 } 903 904 // [PR 3337] Use 'getAs<FunctionType>' to strip away any typedefs on the 905 // function's type. 906 const FunctionType* FT = FD->getType()->getAs<FunctionType>(); 907 const IdentifierInfo *II = FD->getIdentifier(); 908 if (!II) 909 break; 910 911 StringRef FName = II->getName(); 912 913 // Strip away preceding '_'. Doing this here will effect all the checks 914 // down below. 915 FName = FName.substr(FName.find_first_not_of('_')); 916 917 // Inspect the result type. 918 QualType RetTy = FT->getResultType(); 919 920 // FIXME: This should all be refactored into a chain of "summary lookup" 921 // filters. 922 assert(ScratchArgs.isEmpty()); 923 924 if (FName == "pthread_create") { 925 // Part of: <rdar://problem/7299394>. This will be addressed 926 // better with IPA. 927 S = getPersistentStopSummary(); 928 } else if (FName == "NSMakeCollectable") { 929 // Handle: id NSMakeCollectable(CFTypeRef) 930 S = (RetTy->isObjCIdType()) 931 ? getUnarySummary(FT, cfmakecollectable) 932 : getPersistentStopSummary(); 933 } else if (FName == "IOBSDNameMatching" || 934 FName == "IOServiceMatching" || 935 FName == "IOServiceNameMatching" || 936 FName == "IORegistryEntryIDMatching" || 937 FName == "IOOpenFirmwarePathMatching") { 938 // Part of <rdar://problem/6961230>. (IOKit) 939 // This should be addressed using a API table. 940 S = getPersistentSummary(RetEffect::MakeOwned(RetEffect::CF, true), 941 DoNothing, DoNothing); 942 } else if (FName == "IOServiceGetMatchingService" || 943 FName == "IOServiceGetMatchingServices") { 944 // FIXES: <rdar://problem/6326900> 945 // This should be addressed using a API table. This strcmp is also 946 // a little gross, but there is no need to super optimize here. 947 ScratchArgs = AF.add(ScratchArgs, 1, DecRef); 948 S = getPersistentSummary(RetEffect::MakeNoRet(), DoNothing, DoNothing); 949 } else if (FName == "IOServiceAddNotification" || 950 FName == "IOServiceAddMatchingNotification") { 951 // Part of <rdar://problem/6961230>. (IOKit) 952 // This should be addressed using a API table. 953 ScratchArgs = AF.add(ScratchArgs, 2, DecRef); 954 S = getPersistentSummary(RetEffect::MakeNoRet(), DoNothing, DoNothing); 955 } else if (FName == "CVPixelBufferCreateWithBytes") { 956 // FIXES: <rdar://problem/7283567> 957 // Eventually this can be improved by recognizing that the pixel 958 // buffer passed to CVPixelBufferCreateWithBytes is released via 959 // a callback and doing full IPA to make sure this is done correctly. 960 // FIXME: This function has an out parameter that returns an 961 // allocated object. 962 ScratchArgs = AF.add(ScratchArgs, 7, StopTracking); 963 S = getPersistentSummary(RetEffect::MakeNoRet(), DoNothing, DoNothing); 964 } else if (FName == "CGBitmapContextCreateWithData") { 965 // FIXES: <rdar://problem/7358899> 966 // Eventually this can be improved by recognizing that 'releaseInfo' 967 // passed to CGBitmapContextCreateWithData is released via 968 // a callback and doing full IPA to make sure this is done correctly. 969 ScratchArgs = AF.add(ScratchArgs, 8, StopTracking); 970 S = getPersistentSummary(RetEffect::MakeOwned(RetEffect::CF, true), 971 DoNothing, DoNothing); 972 } else if (FName == "CVPixelBufferCreateWithPlanarBytes") { 973 // FIXES: <rdar://problem/7283567> 974 // Eventually this can be improved by recognizing that the pixel 975 // buffer passed to CVPixelBufferCreateWithPlanarBytes is released 976 // via a callback and doing full IPA to make sure this is done 977 // correctly. 978 ScratchArgs = AF.add(ScratchArgs, 12, StopTracking); 979 S = getPersistentSummary(RetEffect::MakeNoRet(), DoNothing, DoNothing); 980 } 981 982 // Did we get a summary? 983 if (S) 984 break; 985 986 // Enable this code once the semantics of NSDeallocateObject are resolved 987 // for GC. <rdar://problem/6619988> 988#if 0 989 // Handle: NSDeallocateObject(id anObject); 990 // This method does allow 'nil' (although we don't check it now). 991 if (strcmp(FName, "NSDeallocateObject") == 0) { 992 return RetTy == Ctx.VoidTy 993 ? getPersistentSummary(RetEffect::MakeNoRet(), DoNothing, Dealloc) 994 : getPersistentStopSummary(); 995 } 996#endif 997 998 if (RetTy->isPointerType()) { 999 // For CoreFoundation ('CF') types. 1000 if (cocoa::isRefType(RetTy, "CF", FName)) { 1001 if (isRetain(FD, FName)) 1002 S = getUnarySummary(FT, cfretain); 1003 else if (isMakeCollectable(FD, FName)) 1004 S = getUnarySummary(FT, cfmakecollectable); 1005 else 1006 S = getCFCreateGetRuleSummary(FD); 1007 1008 break; 1009 } 1010 1011 // For CoreGraphics ('CG') types. 1012 if (cocoa::isRefType(RetTy, "CG", FName)) { 1013 if (isRetain(FD, FName)) 1014 S = getUnarySummary(FT, cfretain); 1015 else 1016 S = getCFCreateGetRuleSummary(FD); 1017 1018 break; 1019 } 1020 1021 // For the Disk Arbitration API (DiskArbitration/DADisk.h) 1022 if (cocoa::isRefType(RetTy, "DADisk") || 1023 cocoa::isRefType(RetTy, "DADissenter") || 1024 cocoa::isRefType(RetTy, "DASessionRef")) { 1025 S = getCFCreateGetRuleSummary(FD); 1026 break; 1027 } 1028 1029 break; 1030 } 1031 1032 // Check for release functions, the only kind of functions that we care 1033 // about that don't return a pointer type. 1034 if (FName[0] == 'C' && (FName[1] == 'F' || FName[1] == 'G')) { 1035 // Test for 'CGCF'. 1036 FName = FName.substr(FName.startswith("CGCF") ? 4 : 2); 1037 1038 if (isRelease(FD, FName)) 1039 S = getUnarySummary(FT, cfrelease); 1040 else { 1041 assert (ScratchArgs.isEmpty()); 1042 // Remaining CoreFoundation and CoreGraphics functions. 1043 // We use to assume that they all strictly followed the ownership idiom 1044 // and that ownership cannot be transferred. While this is technically 1045 // correct, many methods allow a tracked object to escape. For example: 1046 // 1047 // CFMutableDictionaryRef x = CFDictionaryCreateMutable(...); 1048 // CFDictionaryAddValue(y, key, x); 1049 // CFRelease(x); 1050 // ... it is okay to use 'x' since 'y' has a reference to it 1051 // 1052 // We handle this and similar cases with the follow heuristic. If the 1053 // function name contains "InsertValue", "SetValue", "AddValue", 1054 // "AppendValue", or "SetAttribute", then we assume that arguments may 1055 // "escape." This means that something else holds on to the object, 1056 // allowing it be used even after its local retain count drops to 0. 1057 ArgEffect E = (StrInStrNoCase(FName, "InsertValue") != StringRef::npos|| 1058 StrInStrNoCase(FName, "AddValue") != StringRef::npos || 1059 StrInStrNoCase(FName, "SetValue") != StringRef::npos || 1060 StrInStrNoCase(FName, "AppendValue") != StringRef::npos|| 1061 StrInStrNoCase(FName, "SetAttribute") != StringRef::npos) 1062 ? MayEscape : DoNothing; 1063 1064 S = getPersistentSummary(RetEffect::MakeNoRet(), DoNothing, E); 1065 } 1066 } 1067 } 1068 while (0); 1069 1070 // Annotations override defaults. 1071 updateSummaryFromAnnotations(S, FD); 1072 1073 FuncSummaries[FD] = S; 1074 return S; 1075} 1076 1077const RetainSummary * 1078RetainSummaryManager::getCFCreateGetRuleSummary(const FunctionDecl *FD) { 1079 if (coreFoundation::followsCreateRule(FD)) 1080 return getCFSummaryCreateRule(FD); 1081 1082 return getCFSummaryGetRule(FD); 1083} 1084 1085const RetainSummary * 1086RetainSummaryManager::getUnarySummary(const FunctionType* FT, 1087 UnaryFuncKind func) { 1088 1089 // Sanity check that this is *really* a unary function. This can 1090 // happen if people do weird things. 1091 const FunctionProtoType* FTP = dyn_cast<FunctionProtoType>(FT); 1092 if (!FTP || FTP->getNumArgs() != 1) 1093 return getPersistentStopSummary(); 1094 1095 assert (ScratchArgs.isEmpty()); 1096 1097 ArgEffect Effect; 1098 switch (func) { 1099 case cfretain: Effect = IncRef; break; 1100 case cfrelease: Effect = DecRef; break; 1101 case cfmakecollectable: Effect = MakeCollectable; break; 1102 default: llvm_unreachable("Not a supported unary function."); 1103 } 1104 1105 ScratchArgs = AF.add(ScratchArgs, 0, Effect); 1106 return getPersistentSummary(RetEffect::MakeNoRet(), DoNothing, DoNothing); 1107} 1108 1109const RetainSummary * 1110RetainSummaryManager::getCFSummaryCreateRule(const FunctionDecl *FD) { 1111 assert (ScratchArgs.isEmpty()); 1112 1113 return getPersistentSummary(RetEffect::MakeOwned(RetEffect::CF, true)); 1114} 1115 1116const RetainSummary * 1117RetainSummaryManager::getCFSummaryGetRule(const FunctionDecl *FD) { 1118 assert (ScratchArgs.isEmpty()); 1119 return getPersistentSummary(RetEffect::MakeNotOwned(RetEffect::CF), 1120 DoNothing, DoNothing); 1121} 1122 1123//===----------------------------------------------------------------------===// 1124// Summary creation for Selectors. 1125//===----------------------------------------------------------------------===// 1126 1127const RetainSummary * 1128RetainSummaryManager::getInitMethodSummary(QualType RetTy) { 1129 assert(ScratchArgs.isEmpty()); 1130 // 'init' methods conceptually return a newly allocated object and claim 1131 // the receiver. 1132 if (cocoa::isCocoaObjectRef(RetTy) || 1133 coreFoundation::isCFObjectRef(RetTy)) 1134 return getPersistentSummary(ObjCInitRetE, DecRefMsg); 1135 1136 return getDefaultSummary(); 1137} 1138 1139void 1140RetainSummaryManager::updateSummaryFromAnnotations(const RetainSummary *&Summ, 1141 const FunctionDecl *FD) { 1142 if (!FD) 1143 return; 1144 1145 RetainSummaryTemplate Template(Summ, DefaultSummary, *this); 1146 1147 // Effects on the parameters. 1148 unsigned parm_idx = 0; 1149 for (FunctionDecl::param_const_iterator pi = FD->param_begin(), 1150 pe = FD->param_end(); pi != pe; ++pi, ++parm_idx) { 1151 const ParmVarDecl *pd = *pi; 1152 if (pd->getAttr<NSConsumedAttr>()) { 1153 if (!GCEnabled) { 1154 Template->addArg(AF, parm_idx, DecRef); 1155 } 1156 } else if (pd->getAttr<CFConsumedAttr>()) { 1157 Template->addArg(AF, parm_idx, DecRef); 1158 } 1159 } 1160 1161 QualType RetTy = FD->getResultType(); 1162 1163 // Determine if there is a special return effect for this method. 1164 if (cocoa::isCocoaObjectRef(RetTy)) { 1165 if (FD->getAttr<NSReturnsRetainedAttr>()) { 1166 Template->setRetEffect(ObjCAllocRetE); 1167 } 1168 else if (FD->getAttr<CFReturnsRetainedAttr>()) { 1169 Template->setRetEffect(RetEffect::MakeOwned(RetEffect::CF, true)); 1170 } 1171 else if (FD->getAttr<NSReturnsNotRetainedAttr>()) { 1172 Template->setRetEffect(RetEffect::MakeNotOwned(RetEffect::ObjC)); 1173 } 1174 else if (FD->getAttr<CFReturnsNotRetainedAttr>()) { 1175 Template->setRetEffect(RetEffect::MakeNotOwned(RetEffect::CF)); 1176 } 1177 } else if (RetTy->getAs<PointerType>()) { 1178 if (FD->getAttr<CFReturnsRetainedAttr>()) { 1179 Template->setRetEffect(RetEffect::MakeOwned(RetEffect::CF, true)); 1180 } 1181 else if (FD->getAttr<CFReturnsNotRetainedAttr>()) { 1182 Template->setRetEffect(RetEffect::MakeNotOwned(RetEffect::CF)); 1183 } 1184 } 1185} 1186 1187void 1188RetainSummaryManager::updateSummaryFromAnnotations(const RetainSummary *&Summ, 1189 const ObjCMethodDecl *MD) { 1190 if (!MD) 1191 return; 1192 1193 RetainSummaryTemplate Template(Summ, DefaultSummary, *this); 1194 1195 bool isTrackedLoc = false; 1196 1197 // Effects on the receiver. 1198 if (MD->getAttr<NSConsumesSelfAttr>()) { 1199 if (!GCEnabled) 1200 Template->setReceiverEffect(DecRefMsg); 1201 } 1202 1203 // Effects on the parameters. 1204 unsigned parm_idx = 0; 1205 for (ObjCMethodDecl::param_const_iterator 1206 pi=MD->param_begin(), pe=MD->param_end(); 1207 pi != pe; ++pi, ++parm_idx) { 1208 const ParmVarDecl *pd = *pi; 1209 if (pd->getAttr<NSConsumedAttr>()) { 1210 if (!GCEnabled) 1211 Template->addArg(AF, parm_idx, DecRef); 1212 } 1213 else if(pd->getAttr<CFConsumedAttr>()) { 1214 Template->addArg(AF, parm_idx, DecRef); 1215 } 1216 } 1217 1218 // Determine if there is a special return effect for this method. 1219 if (cocoa::isCocoaObjectRef(MD->getResultType())) { 1220 if (MD->getAttr<NSReturnsRetainedAttr>()) { 1221 Template->setRetEffect(ObjCAllocRetE); 1222 return; 1223 } 1224 if (MD->getAttr<NSReturnsNotRetainedAttr>()) { 1225 Template->setRetEffect(RetEffect::MakeNotOwned(RetEffect::ObjC)); 1226 return; 1227 } 1228 1229 isTrackedLoc = true; 1230 } else { 1231 isTrackedLoc = MD->getResultType()->getAs<PointerType>() != NULL; 1232 } 1233 1234 if (isTrackedLoc) { 1235 if (MD->getAttr<CFReturnsRetainedAttr>()) 1236 Template->setRetEffect(RetEffect::MakeOwned(RetEffect::CF, true)); 1237 else if (MD->getAttr<CFReturnsNotRetainedAttr>()) 1238 Template->setRetEffect(RetEffect::MakeNotOwned(RetEffect::CF)); 1239 } 1240} 1241 1242const RetainSummary * 1243RetainSummaryManager::getCommonMethodSummary(const ObjCMethodDecl *MD, 1244 Selector S, QualType RetTy) { 1245 1246 if (MD) { 1247 // Scan the method decl for 'void*' arguments. These should be treated 1248 // as 'StopTracking' because they are often used with delegates. 1249 // Delegates are a frequent form of false positives with the retain 1250 // count checker. 1251 unsigned i = 0; 1252 for (ObjCMethodDecl::param_const_iterator I = MD->param_begin(), 1253 E = MD->param_end(); I != E; ++I, ++i) 1254 if (const ParmVarDecl *PD = *I) { 1255 QualType Ty = Ctx.getCanonicalType(PD->getType()); 1256 if (Ty.getLocalUnqualifiedType() == Ctx.VoidPtrTy) 1257 ScratchArgs = AF.add(ScratchArgs, i, StopTracking); 1258 } 1259 } 1260 1261 // Any special effect for the receiver? 1262 ArgEffect ReceiverEff = DoNothing; 1263 1264 // If one of the arguments in the selector has the keyword 'delegate' we 1265 // should stop tracking the reference count for the receiver. This is 1266 // because the reference count is quite possibly handled by a delegate 1267 // method. 1268 if (S.isKeywordSelector()) { 1269 const std::string &str = S.getAsString(); 1270 assert(!str.empty()); 1271 if (StrInStrNoCase(str, "delegate:") != StringRef::npos) 1272 ReceiverEff = StopTracking; 1273 } 1274 1275 // Look for methods that return an owned object. 1276 if (cocoa::isCocoaObjectRef(RetTy)) { 1277 // EXPERIMENTAL: assume the Cocoa conventions for all objects returned 1278 // by instance methods. 1279 RetEffect E = cocoa::followsFundamentalRule(S, MD) 1280 ? ObjCAllocRetE : RetEffect::MakeNotOwned(RetEffect::ObjC); 1281 1282 return getPersistentSummary(E, ReceiverEff, MayEscape); 1283 } 1284 1285 // Look for methods that return an owned core foundation object. 1286 if (coreFoundation::isCFObjectRef(RetTy)) { 1287 RetEffect E = cocoa::followsFundamentalRule(S, MD) 1288 ? RetEffect::MakeOwned(RetEffect::CF, true) 1289 : RetEffect::MakeNotOwned(RetEffect::CF); 1290 1291 return getPersistentSummary(E, ReceiverEff, MayEscape); 1292 } 1293 1294 if (ScratchArgs.isEmpty() && ReceiverEff == DoNothing) 1295 return getDefaultSummary(); 1296 1297 return getPersistentSummary(RetEffect::MakeNoRet(), ReceiverEff, MayEscape); 1298} 1299 1300const RetainSummary * 1301RetainSummaryManager::getInstanceMethodSummary(const ObjCMessage &msg, 1302 const ProgramState *state, 1303 const LocationContext *LC) { 1304 1305 // We need the type-information of the tracked receiver object 1306 // Retrieve it from the state. 1307 const Expr *Receiver = msg.getInstanceReceiver(); 1308 const ObjCInterfaceDecl *ID = 0; 1309 1310 // FIXME: Is this really working as expected? There are cases where 1311 // we just use the 'ID' from the message expression. 1312 SVal receiverV; 1313 1314 if (Receiver) { 1315 receiverV = state->getSValAsScalarOrLoc(Receiver); 1316 1317 // FIXME: Eventually replace the use of state->get<RefBindings> with 1318 // a generic API for reasoning about the Objective-C types of symbolic 1319 // objects. 1320 if (SymbolRef Sym = receiverV.getAsLocSymbol()) 1321 if (const RefVal *T = state->get<RefBindings>(Sym)) 1322 if (const ObjCObjectPointerType* PT = 1323 T->getType()->getAs<ObjCObjectPointerType>()) 1324 ID = PT->getInterfaceDecl(); 1325 1326 // FIXME: this is a hack. This may or may not be the actual method 1327 // that is called. 1328 if (!ID) { 1329 if (const ObjCObjectPointerType *PT = 1330 Receiver->getType()->getAs<ObjCObjectPointerType>()) 1331 ID = PT->getInterfaceDecl(); 1332 } 1333 } else { 1334 // FIXME: Hack for 'super'. 1335 ID = msg.getReceiverInterface(); 1336 } 1337 1338 // FIXME: The receiver could be a reference to a class, meaning that 1339 // we should use the class method. 1340 return getInstanceMethodSummary(msg, ID); 1341} 1342 1343const RetainSummary * 1344RetainSummaryManager::getInstanceMethodSummary(Selector S, 1345 IdentifierInfo *ClsName, 1346 const ObjCInterfaceDecl *ID, 1347 const ObjCMethodDecl *MD, 1348 QualType RetTy) { 1349 1350 // Look up a summary in our summary cache. 1351 const RetainSummary *Summ = ObjCMethodSummaries.find(ID, ClsName, S); 1352 1353 if (!Summ) { 1354 assert(ScratchArgs.isEmpty()); 1355 1356 // "initXXX": pass-through for receiver. 1357 if (cocoa::deriveNamingConvention(S, MD) == cocoa::InitRule) 1358 Summ = getInitMethodSummary(RetTy); 1359 else 1360 Summ = getCommonMethodSummary(MD, S, RetTy); 1361 1362 // Annotations override defaults. 1363 updateSummaryFromAnnotations(Summ, MD); 1364 1365 // Memoize the summary. 1366 ObjCMethodSummaries[ObjCSummaryKey(ID, ClsName, S)] = Summ; 1367 } 1368 1369 return Summ; 1370} 1371 1372const RetainSummary * 1373RetainSummaryManager::getClassMethodSummary(Selector S, IdentifierInfo *ClsName, 1374 const ObjCInterfaceDecl *ID, 1375 const ObjCMethodDecl *MD, 1376 QualType RetTy) { 1377 1378 assert(ClsName && "Class name must be specified."); 1379 const RetainSummary *Summ = ObjCClassMethodSummaries.find(ID, ClsName, S); 1380 1381 if (!Summ) { 1382 Summ = getCommonMethodSummary(MD, S, RetTy); 1383 1384 // Annotations override defaults. 1385 updateSummaryFromAnnotations(Summ, MD); 1386 1387 // Memoize the summary. 1388 ObjCClassMethodSummaries[ObjCSummaryKey(ID, ClsName, S)] = Summ; 1389 } 1390 1391 return Summ; 1392} 1393 1394void RetainSummaryManager::InitializeClassMethodSummaries() { 1395 assert(ScratchArgs.isEmpty()); 1396 // Create the [NSAssertionHandler currentHander] summary. 1397 addClassMethSummary("NSAssertionHandler", "currentHandler", 1398 getPersistentSummary(RetEffect::MakeNotOwned(RetEffect::ObjC))); 1399 1400 // Create the [NSAutoreleasePool addObject:] summary. 1401 ScratchArgs = AF.add(ScratchArgs, 0, Autorelease); 1402 addClassMethSummary("NSAutoreleasePool", "addObject", 1403 getPersistentSummary(RetEffect::MakeNoRet(), 1404 DoNothing, Autorelease)); 1405 1406 // Create the summaries for [NSObject performSelector...]. We treat 1407 // these as 'stop tracking' for the arguments because they are often 1408 // used for delegates that can release the object. When we have better 1409 // inter-procedural analysis we can potentially do something better. This 1410 // workaround is to remove false positives. 1411 const RetainSummary *Summ = 1412 getPersistentSummary(RetEffect::MakeNoRet(), DoNothing, StopTracking); 1413 IdentifierInfo *NSObjectII = &Ctx.Idents.get("NSObject"); 1414 addClsMethSummary(NSObjectII, Summ, "performSelector", "withObject", 1415 "afterDelay", NULL); 1416 addClsMethSummary(NSObjectII, Summ, "performSelector", "withObject", 1417 "afterDelay", "inModes", NULL); 1418 addClsMethSummary(NSObjectII, Summ, "performSelectorOnMainThread", 1419 "withObject", "waitUntilDone", NULL); 1420 addClsMethSummary(NSObjectII, Summ, "performSelectorOnMainThread", 1421 "withObject", "waitUntilDone", "modes", NULL); 1422 addClsMethSummary(NSObjectII, Summ, "performSelector", "onThread", 1423 "withObject", "waitUntilDone", NULL); 1424 addClsMethSummary(NSObjectII, Summ, "performSelector", "onThread", 1425 "withObject", "waitUntilDone", "modes", NULL); 1426 addClsMethSummary(NSObjectII, Summ, "performSelectorInBackground", 1427 "withObject", NULL); 1428} 1429 1430void RetainSummaryManager::InitializeMethodSummaries() { 1431 1432 assert (ScratchArgs.isEmpty()); 1433 1434 // Create the "init" selector. It just acts as a pass-through for the 1435 // receiver. 1436 const RetainSummary *InitSumm = getPersistentSummary(ObjCInitRetE, DecRefMsg); 1437 addNSObjectMethSummary(GetNullarySelector("init", Ctx), InitSumm); 1438 1439 // awakeAfterUsingCoder: behaves basically like an 'init' method. It 1440 // claims the receiver and returns a retained object. 1441 addNSObjectMethSummary(GetUnarySelector("awakeAfterUsingCoder", Ctx), 1442 InitSumm); 1443 1444 // The next methods are allocators. 1445 const RetainSummary *AllocSumm = getPersistentSummary(ObjCAllocRetE); 1446 const RetainSummary *CFAllocSumm = 1447 getPersistentSummary(RetEffect::MakeOwned(RetEffect::CF, true)); 1448 1449 // Create the "retain" selector. 1450 RetEffect NoRet = RetEffect::MakeNoRet(); 1451 const RetainSummary *Summ = getPersistentSummary(NoRet, IncRefMsg); 1452 addNSObjectMethSummary(GetNullarySelector("retain", Ctx), Summ); 1453 1454 // Create the "release" selector. 1455 Summ = getPersistentSummary(NoRet, DecRefMsg); 1456 addNSObjectMethSummary(GetNullarySelector("release", Ctx), Summ); 1457 1458 // Create the "drain" selector. 1459 Summ = getPersistentSummary(NoRet, isGCEnabled() ? DoNothing : DecRef); 1460 addNSObjectMethSummary(GetNullarySelector("drain", Ctx), Summ); 1461 1462 // Create the -dealloc summary. 1463 Summ = getPersistentSummary(NoRet, Dealloc); 1464 addNSObjectMethSummary(GetNullarySelector("dealloc", Ctx), Summ); 1465 1466 // Create the "autorelease" selector. 1467 Summ = getPersistentSummary(NoRet, Autorelease); 1468 addNSObjectMethSummary(GetNullarySelector("autorelease", Ctx), Summ); 1469 1470 // Specially handle NSAutoreleasePool. 1471 addInstMethSummary("NSAutoreleasePool", "init", 1472 getPersistentSummary(NoRet, NewAutoreleasePool)); 1473 1474 // For NSWindow, allocated objects are (initially) self-owned. 1475 // FIXME: For now we opt for false negatives with NSWindow, as these objects 1476 // self-own themselves. However, they only do this once they are displayed. 1477 // Thus, we need to track an NSWindow's display status. 1478 // This is tracked in <rdar://problem/6062711>. 1479 // See also http://llvm.org/bugs/show_bug.cgi?id=3714. 1480 const RetainSummary *NoTrackYet = getPersistentSummary(RetEffect::MakeNoRet(), 1481 StopTracking, 1482 StopTracking); 1483 1484 addClassMethSummary("NSWindow", "alloc", NoTrackYet); 1485 1486#if 0 1487 addInstMethSummary("NSWindow", NoTrackYet, "initWithContentRect", 1488 "styleMask", "backing", "defer", NULL); 1489 1490 addInstMethSummary("NSWindow", NoTrackYet, "initWithContentRect", 1491 "styleMask", "backing", "defer", "screen", NULL); 1492#endif 1493 1494 // For NSPanel (which subclasses NSWindow), allocated objects are not 1495 // self-owned. 1496 // FIXME: For now we don't track NSPanels. object for the same reason 1497 // as for NSWindow objects. 1498 addClassMethSummary("NSPanel", "alloc", NoTrackYet); 1499 1500#if 0 1501 addInstMethSummary("NSPanel", NoTrackYet, "initWithContentRect", 1502 "styleMask", "backing", "defer", NULL); 1503 1504 addInstMethSummary("NSPanel", NoTrackYet, "initWithContentRect", 1505 "styleMask", "backing", "defer", "screen", NULL); 1506#endif 1507 1508 // Don't track allocated autorelease pools yet, as it is okay to prematurely 1509 // exit a method. 1510 addClassMethSummary("NSAutoreleasePool", "alloc", NoTrackYet); 1511 1512 // Create summaries QCRenderer/QCView -createSnapShotImageOfType: 1513 addInstMethSummary("QCRenderer", AllocSumm, 1514 "createSnapshotImageOfType", NULL); 1515 addInstMethSummary("QCView", AllocSumm, 1516 "createSnapshotImageOfType", NULL); 1517 1518 // Create summaries for CIContext, 'createCGImage' and 1519 // 'createCGLayerWithSize'. These objects are CF objects, and are not 1520 // automatically garbage collected. 1521 addInstMethSummary("CIContext", CFAllocSumm, 1522 "createCGImage", "fromRect", NULL); 1523 addInstMethSummary("CIContext", CFAllocSumm, 1524 "createCGImage", "fromRect", "format", "colorSpace", NULL); 1525 addInstMethSummary("CIContext", CFAllocSumm, "createCGLayerWithSize", 1526 "info", NULL); 1527} 1528 1529//===----------------------------------------------------------------------===// 1530// AutoreleaseBindings - State used to track objects in autorelease pools. 1531//===----------------------------------------------------------------------===// 1532 1533typedef llvm::ImmutableMap<SymbolRef, unsigned> ARCounts; 1534typedef llvm::ImmutableMap<SymbolRef, ARCounts> ARPoolContents; 1535typedef llvm::ImmutableList<SymbolRef> ARStack; 1536 1537static int AutoRCIndex = 0; 1538static int AutoRBIndex = 0; 1539 1540namespace { class AutoreleasePoolContents {}; } 1541namespace { class AutoreleaseStack {}; } 1542 1543namespace clang { 1544namespace ento { 1545template<> struct ProgramStateTrait<AutoreleaseStack> 1546 : public ProgramStatePartialTrait<ARStack> { 1547 static inline void *GDMIndex() { return &AutoRBIndex; } 1548}; 1549 1550template<> struct ProgramStateTrait<AutoreleasePoolContents> 1551 : public ProgramStatePartialTrait<ARPoolContents> { 1552 static inline void *GDMIndex() { return &AutoRCIndex; } 1553}; 1554} // end GR namespace 1555} // end clang namespace 1556 1557static SymbolRef GetCurrentAutoreleasePool(const ProgramState *state) { 1558 ARStack stack = state->get<AutoreleaseStack>(); 1559 return stack.isEmpty() ? SymbolRef() : stack.getHead(); 1560} 1561 1562static const ProgramState * 1563SendAutorelease(const ProgramState *state, 1564 ARCounts::Factory &F, 1565 SymbolRef sym) { 1566 SymbolRef pool = GetCurrentAutoreleasePool(state); 1567 const ARCounts *cnts = state->get<AutoreleasePoolContents>(pool); 1568 ARCounts newCnts(0); 1569 1570 if (cnts) { 1571 const unsigned *cnt = (*cnts).lookup(sym); 1572 newCnts = F.add(*cnts, sym, cnt ? *cnt + 1 : 1); 1573 } 1574 else 1575 newCnts = F.add(F.getEmptyMap(), sym, 1); 1576 1577 return state->set<AutoreleasePoolContents>(pool, newCnts); 1578} 1579 1580//===----------------------------------------------------------------------===// 1581// Error reporting. 1582//===----------------------------------------------------------------------===// 1583namespace { 1584 typedef llvm::DenseMap<const ExplodedNode *, const RetainSummary *> 1585 SummaryLogTy; 1586 1587 //===-------------===// 1588 // Bug Descriptions. // 1589 //===-------------===// 1590 1591 class CFRefBug : public BugType { 1592 protected: 1593 CFRefBug(StringRef name) 1594 : BugType(name, "Memory (Core Foundation/Objective-C)") {} 1595 public: 1596 1597 // FIXME: Eventually remove. 1598 virtual const char *getDescription() const = 0; 1599 1600 virtual bool isLeak() const { return false; } 1601 }; 1602 1603 class UseAfterRelease : public CFRefBug { 1604 public: 1605 UseAfterRelease() : CFRefBug("Use-after-release") {} 1606 1607 const char *getDescription() const { 1608 return "Reference-counted object is used after it is released"; 1609 } 1610 }; 1611 1612 class BadRelease : public CFRefBug { 1613 public: 1614 BadRelease() : CFRefBug("Bad release") {} 1615 1616 const char *getDescription() const { 1617 return "Incorrect decrement of the reference count of an object that is " 1618 "not owned at this point by the caller"; 1619 } 1620 }; 1621 1622 class DeallocGC : public CFRefBug { 1623 public: 1624 DeallocGC() 1625 : CFRefBug("-dealloc called while using garbage collection") {} 1626 1627 const char *getDescription() const { 1628 return "-dealloc called while using garbage collection"; 1629 } 1630 }; 1631 1632 class DeallocNotOwned : public CFRefBug { 1633 public: 1634 DeallocNotOwned() 1635 : CFRefBug("-dealloc sent to non-exclusively owned object") {} 1636 1637 const char *getDescription() const { 1638 return "-dealloc sent to object that may be referenced elsewhere"; 1639 } 1640 }; 1641 1642 class OverAutorelease : public CFRefBug { 1643 public: 1644 OverAutorelease() 1645 : CFRefBug("Object sent -autorelease too many times") {} 1646 1647 const char *getDescription() const { 1648 return "Object sent -autorelease too many times"; 1649 } 1650 }; 1651 1652 class ReturnedNotOwnedForOwned : public CFRefBug { 1653 public: 1654 ReturnedNotOwnedForOwned() 1655 : CFRefBug("Method should return an owned object") {} 1656 1657 const char *getDescription() const { 1658 return "Object with a +0 retain count returned to caller where a +1 " 1659 "(owning) retain count is expected"; 1660 } 1661 }; 1662 1663 class Leak : public CFRefBug { 1664 const bool isReturn; 1665 protected: 1666 Leak(StringRef name, bool isRet) 1667 : CFRefBug(name), isReturn(isRet) { 1668 // Leaks should not be reported if they are post-dominated by a sink. 1669 setSuppressOnSink(true); 1670 } 1671 public: 1672 1673 const char *getDescription() const { return ""; } 1674 1675 bool isLeak() const { return true; } 1676 }; 1677 1678 class LeakAtReturn : public Leak { 1679 public: 1680 LeakAtReturn(StringRef name) 1681 : Leak(name, true) {} 1682 }; 1683 1684 class LeakWithinFunction : public Leak { 1685 public: 1686 LeakWithinFunction(StringRef name) 1687 : Leak(name, false) {} 1688 }; 1689 1690 //===---------===// 1691 // Bug Reports. // 1692 //===---------===// 1693 1694 class CFRefReportVisitor : public BugReporterVisitor { 1695 protected: 1696 SymbolRef Sym; 1697 const SummaryLogTy &SummaryLog; 1698 bool GCEnabled; 1699 1700 public: 1701 CFRefReportVisitor(SymbolRef sym, bool gcEnabled, const SummaryLogTy &log) 1702 : Sym(sym), SummaryLog(log), GCEnabled(gcEnabled) {} 1703 1704 virtual void Profile(llvm::FoldingSetNodeID &ID) const { 1705 static int x = 0; 1706 ID.AddPointer(&x); 1707 ID.AddPointer(Sym); 1708 } 1709 1710 virtual PathDiagnosticPiece *VisitNode(const ExplodedNode *N, 1711 const ExplodedNode *PrevN, 1712 BugReporterContext &BRC, 1713 BugReport &BR); 1714 1715 virtual PathDiagnosticPiece *getEndPath(BugReporterContext &BRC, 1716 const ExplodedNode *N, 1717 BugReport &BR); 1718 }; 1719 1720 class CFRefLeakReportVisitor : public CFRefReportVisitor { 1721 public: 1722 CFRefLeakReportVisitor(SymbolRef sym, bool GCEnabled, 1723 const SummaryLogTy &log) 1724 : CFRefReportVisitor(sym, GCEnabled, log) {} 1725 1726 PathDiagnosticPiece *getEndPath(BugReporterContext &BRC, 1727 const ExplodedNode *N, 1728 BugReport &BR); 1729 }; 1730 1731 class CFRefReport : public BugReport { 1732 void addGCModeDescription(const LangOptions &LOpts, bool GCEnabled); 1733 1734 public: 1735 CFRefReport(CFRefBug &D, const LangOptions &LOpts, bool GCEnabled, 1736 const SummaryLogTy &Log, ExplodedNode *n, SymbolRef sym, 1737 bool registerVisitor = true) 1738 : BugReport(D, D.getDescription(), n) { 1739 if (registerVisitor) 1740 addVisitor(new CFRefReportVisitor(sym, GCEnabled, Log)); 1741 addGCModeDescription(LOpts, GCEnabled); 1742 } 1743 1744 CFRefReport(CFRefBug &D, const LangOptions &LOpts, bool GCEnabled, 1745 const SummaryLogTy &Log, ExplodedNode *n, SymbolRef sym, 1746 StringRef endText) 1747 : BugReport(D, D.getDescription(), endText, n) { 1748 addVisitor(new CFRefReportVisitor(sym, GCEnabled, Log)); 1749 addGCModeDescription(LOpts, GCEnabled); 1750 } 1751 1752 virtual std::pair<ranges_iterator, ranges_iterator> getRanges() { 1753 const CFRefBug& BugTy = static_cast<CFRefBug&>(getBugType()); 1754 if (!BugTy.isLeak()) 1755 return BugReport::getRanges(); 1756 else 1757 return std::make_pair(ranges_iterator(), ranges_iterator()); 1758 } 1759 }; 1760 1761 class CFRefLeakReport : public CFRefReport { 1762 const MemRegion* AllocBinding; 1763 1764 public: 1765 CFRefLeakReport(CFRefBug &D, const LangOptions &LOpts, bool GCEnabled, 1766 const SummaryLogTy &Log, ExplodedNode *n, SymbolRef sym, 1767 CheckerContext &Ctx); 1768 1769 PathDiagnosticLocation getLocation(const SourceManager &SM) const { 1770 assert(Location.isValid()); 1771 return Location; 1772 } 1773 }; 1774} // end anonymous namespace 1775 1776void CFRefReport::addGCModeDescription(const LangOptions &LOpts, 1777 bool GCEnabled) { 1778 const char *GCModeDescription = 0; 1779 1780 switch (LOpts.getGC()) { 1781 case LangOptions::GCOnly: 1782 assert(GCEnabled); 1783 GCModeDescription = "Code is compiled to only use garbage collection"; 1784 break; 1785 1786 case LangOptions::NonGC: 1787 assert(!GCEnabled); 1788 GCModeDescription = "Code is compiled to use reference counts"; 1789 break; 1790 1791 case LangOptions::HybridGC: 1792 if (GCEnabled) { 1793 GCModeDescription = "Code is compiled to use either garbage collection " 1794 "(GC) or reference counts (non-GC). The bug occurs " 1795 "with GC enabled"; 1796 break; 1797 } else { 1798 GCModeDescription = "Code is compiled to use either garbage collection " 1799 "(GC) or reference counts (non-GC). The bug occurs " 1800 "in non-GC mode"; 1801 break; 1802 } 1803 } 1804 1805 assert(GCModeDescription && "invalid/unknown GC mode"); 1806 addExtraText(GCModeDescription); 1807} 1808 1809// FIXME: This should be a method on SmallVector. 1810static inline bool contains(const SmallVectorImpl<ArgEffect>& V, 1811 ArgEffect X) { 1812 for (SmallVectorImpl<ArgEffect>::const_iterator I=V.begin(), E=V.end(); 1813 I!=E; ++I) 1814 if (*I == X) return true; 1815 1816 return false; 1817} 1818 1819static bool isPropertyAccess(const Stmt *S, ParentMap &PM) { 1820 unsigned maxDepth = 4; 1821 while (S && maxDepth) { 1822 if (const PseudoObjectExpr *PO = dyn_cast<PseudoObjectExpr>(S)) { 1823 if (!isa<ObjCMessageExpr>(PO->getSyntacticForm())) 1824 return true; 1825 return false; 1826 } 1827 S = PM.getParent(S); 1828 --maxDepth; 1829 } 1830 return false; 1831} 1832 1833PathDiagnosticPiece *CFRefReportVisitor::VisitNode(const ExplodedNode *N, 1834 const ExplodedNode *PrevN, 1835 BugReporterContext &BRC, 1836 BugReport &BR) { 1837 1838 if (!isa<StmtPoint>(N->getLocation())) 1839 return NULL; 1840 1841 // Check if the type state has changed. 1842 const ProgramState *PrevSt = PrevN->getState(); 1843 const ProgramState *CurrSt = N->getState(); 1844 1845 const RefVal* CurrT = CurrSt->get<RefBindings>(Sym); 1846 if (!CurrT) return NULL; 1847 1848 const RefVal &CurrV = *CurrT; 1849 const RefVal *PrevT = PrevSt->get<RefBindings>(Sym); 1850 1851 // Create a string buffer to constain all the useful things we want 1852 // to tell the user. 1853 std::string sbuf; 1854 llvm::raw_string_ostream os(sbuf); 1855 1856 // This is the allocation site since the previous node had no bindings 1857 // for this symbol. 1858 if (!PrevT) { 1859 const Stmt *S = cast<StmtPoint>(N->getLocation()).getStmt(); 1860 1861 if (const CallExpr *CE = dyn_cast<CallExpr>(S)) { 1862 // Get the name of the callee (if it is available). 1863 SVal X = CurrSt->getSValAsScalarOrLoc(CE->getCallee()); 1864 if (const FunctionDecl *FD = X.getAsFunctionDecl()) 1865 os << "Call to function '" << *FD << '\''; 1866 else 1867 os << "function call"; 1868 } 1869 else { 1870 assert(isa<ObjCMessageExpr>(S)); 1871 // The message expression may have between written directly or as 1872 // a property access. Lazily determine which case we are looking at. 1873 os << (isPropertyAccess(S, N->getParentMap()) ? "Property" : "Method"); 1874 } 1875 1876 if (CurrV.getObjKind() == RetEffect::CF) { 1877 os << " returns a Core Foundation object with a "; 1878 } 1879 else { 1880 assert (CurrV.getObjKind() == RetEffect::ObjC); 1881 os << " returns an Objective-C object with a "; 1882 } 1883 1884 if (CurrV.isOwned()) { 1885 os << "+1 retain count"; 1886 1887 if (GCEnabled) { 1888 assert(CurrV.getObjKind() == RetEffect::CF); 1889 os << ". " 1890 "Core Foundation objects are not automatically garbage collected."; 1891 } 1892 } 1893 else { 1894 assert (CurrV.isNotOwned()); 1895 os << "+0 retain count"; 1896 } 1897 1898 PathDiagnosticLocation Pos(S, BRC.getSourceManager(), 1899 N->getLocationContext()); 1900 return new PathDiagnosticEventPiece(Pos, os.str()); 1901 } 1902 1903 // Gather up the effects that were performed on the object at this 1904 // program point 1905 SmallVector<ArgEffect, 2> AEffects; 1906 1907 const ExplodedNode *OrigNode = BRC.getNodeResolver().getOriginalNode(N); 1908 if (const RetainSummary *Summ = SummaryLog.lookup(OrigNode)) { 1909 // We only have summaries attached to nodes after evaluating CallExpr and 1910 // ObjCMessageExprs. 1911 const Stmt *S = cast<StmtPoint>(N->getLocation()).getStmt(); 1912 1913 if (const CallExpr *CE = dyn_cast<CallExpr>(S)) { 1914 // Iterate through the parameter expressions and see if the symbol 1915 // was ever passed as an argument. 1916 unsigned i = 0; 1917 1918 for (CallExpr::const_arg_iterator AI=CE->arg_begin(), AE=CE->arg_end(); 1919 AI!=AE; ++AI, ++i) { 1920 1921 // Retrieve the value of the argument. Is it the symbol 1922 // we are interested in? 1923 if (CurrSt->getSValAsScalarOrLoc(*AI).getAsLocSymbol() != Sym) 1924 continue; 1925 1926 // We have an argument. Get the effect! 1927 AEffects.push_back(Summ->getArg(i)); 1928 } 1929 } 1930 else if (const ObjCMessageExpr *ME = dyn_cast<ObjCMessageExpr>(S)) { 1931 if (const Expr *receiver = ME->getInstanceReceiver()) 1932 if (CurrSt->getSValAsScalarOrLoc(receiver).getAsLocSymbol() == Sym) { 1933 // The symbol we are tracking is the receiver. 1934 AEffects.push_back(Summ->getReceiverEffect()); 1935 } 1936 } 1937 } 1938 1939 do { 1940 // Get the previous type state. 1941 RefVal PrevV = *PrevT; 1942 1943 // Specially handle -dealloc. 1944 if (!GCEnabled && contains(AEffects, Dealloc)) { 1945 // Determine if the object's reference count was pushed to zero. 1946 assert(!(PrevV == CurrV) && "The typestate *must* have changed."); 1947 // We may not have transitioned to 'release' if we hit an error. 1948 // This case is handled elsewhere. 1949 if (CurrV.getKind() == RefVal::Released) { 1950 assert(CurrV.getCombinedCounts() == 0); 1951 os << "Object released by directly sending the '-dealloc' message"; 1952 break; 1953 } 1954 } 1955 1956 // Specially handle CFMakeCollectable and friends. 1957 if (contains(AEffects, MakeCollectable)) { 1958 // Get the name of the function. 1959 const Stmt *S = cast<StmtPoint>(N->getLocation()).getStmt(); 1960 SVal X = CurrSt->getSValAsScalarOrLoc(cast<CallExpr>(S)->getCallee()); 1961 const FunctionDecl *FD = X.getAsFunctionDecl(); 1962 1963 if (GCEnabled) { 1964 // Determine if the object's reference count was pushed to zero. 1965 assert(!(PrevV == CurrV) && "The typestate *must* have changed."); 1966 1967 os << "In GC mode a call to '" << *FD 1968 << "' decrements an object's retain count and registers the " 1969 "object with the garbage collector. "; 1970 1971 if (CurrV.getKind() == RefVal::Released) { 1972 assert(CurrV.getCount() == 0); 1973 os << "Since it now has a 0 retain count the object can be " 1974 "automatically collected by the garbage collector."; 1975 } 1976 else 1977 os << "An object must have a 0 retain count to be garbage collected. " 1978 "After this call its retain count is +" << CurrV.getCount() 1979 << '.'; 1980 } 1981 else 1982 os << "When GC is not enabled a call to '" << *FD 1983 << "' has no effect on its argument."; 1984 1985 // Nothing more to say. 1986 break; 1987 } 1988 1989 // Determine if the typestate has changed. 1990 if (!(PrevV == CurrV)) 1991 switch (CurrV.getKind()) { 1992 case RefVal::Owned: 1993 case RefVal::NotOwned: 1994 1995 if (PrevV.getCount() == CurrV.getCount()) { 1996 // Did an autorelease message get sent? 1997 if (PrevV.getAutoreleaseCount() == CurrV.getAutoreleaseCount()) 1998 return 0; 1999 2000 assert(PrevV.getAutoreleaseCount() < CurrV.getAutoreleaseCount()); 2001 os << "Object sent -autorelease message"; 2002 break; 2003 } 2004 2005 if (PrevV.getCount() > CurrV.getCount()) 2006 os << "Reference count decremented."; 2007 else 2008 os << "Reference count incremented."; 2009 2010 if (unsigned Count = CurrV.getCount()) 2011 os << " The object now has a +" << Count << " retain count."; 2012 2013 if (PrevV.getKind() == RefVal::Released) { 2014 assert(GCEnabled && CurrV.getCount() > 0); 2015 os << " The object is not eligible for garbage collection until the " 2016 "retain count reaches 0 again."; 2017 } 2018 2019 break; 2020 2021 case RefVal::Released: 2022 os << "Object released."; 2023 break; 2024 2025 case RefVal::ReturnedOwned: 2026 os << "Object returned to caller as an owning reference (single retain " 2027 "count transferred to caller)"; 2028 break; 2029 2030 case RefVal::ReturnedNotOwned: 2031 os << "Object returned to caller with a +0 retain count"; 2032 break; 2033 2034 default: 2035 return NULL; 2036 } 2037 2038 // Emit any remaining diagnostics for the argument effects (if any). 2039 for (SmallVectorImpl<ArgEffect>::iterator I=AEffects.begin(), 2040 E=AEffects.end(); I != E; ++I) { 2041 2042 // A bunch of things have alternate behavior under GC. 2043 if (GCEnabled) 2044 switch (*I) { 2045 default: break; 2046 case Autorelease: 2047 os << "In GC mode an 'autorelease' has no effect."; 2048 continue; 2049 case IncRefMsg: 2050 os << "In GC mode the 'retain' message has no effect."; 2051 continue; 2052 case DecRefMsg: 2053 os << "In GC mode the 'release' message has no effect."; 2054 continue; 2055 } 2056 } 2057 } while (0); 2058 2059 if (os.str().empty()) 2060 return 0; // We have nothing to say! 2061 2062 const Stmt *S = cast<StmtPoint>(N->getLocation()).getStmt(); 2063 PathDiagnosticLocation Pos(S, BRC.getSourceManager(), 2064 N->getLocationContext()); 2065 PathDiagnosticPiece *P = new PathDiagnosticEventPiece(Pos, os.str()); 2066 2067 // Add the range by scanning the children of the statement for any bindings 2068 // to Sym. 2069 for (Stmt::const_child_iterator I = S->child_begin(), E = S->child_end(); 2070 I!=E; ++I) 2071 if (const Expr *Exp = dyn_cast_or_null<Expr>(*I)) 2072 if (CurrSt->getSValAsScalarOrLoc(Exp).getAsLocSymbol() == Sym) { 2073 P->addRange(Exp->getSourceRange()); 2074 break; 2075 } 2076 2077 return P; 2078} 2079 2080namespace { 2081 class FindUniqueBinding : 2082 public StoreManager::BindingsHandler { 2083 SymbolRef Sym; 2084 const MemRegion* Binding; 2085 bool First; 2086 2087 public: 2088 FindUniqueBinding(SymbolRef sym) : Sym(sym), Binding(0), First(true) {} 2089 2090 bool HandleBinding(StoreManager& SMgr, Store store, const MemRegion* R, 2091 SVal val) { 2092 2093 SymbolRef SymV = val.getAsSymbol(); 2094 if (!SymV || SymV != Sym) 2095 return true; 2096 2097 if (Binding) { 2098 First = false; 2099 return false; 2100 } 2101 else 2102 Binding = R; 2103 2104 return true; 2105 } 2106 2107 operator bool() { return First && Binding; } 2108 const MemRegion* getRegion() { return Binding; } 2109 }; 2110} 2111 2112static std::pair<const ExplodedNode*,const MemRegion*> 2113GetAllocationSite(ProgramStateManager& StateMgr, const ExplodedNode *N, 2114 SymbolRef Sym) { 2115 2116 // Find both first node that referred to the tracked symbol and the 2117 // memory location that value was store to. 2118 const ExplodedNode *Last = N; 2119 const MemRegion* FirstBinding = 0; 2120 2121 while (N) { 2122 const ProgramState *St = N->getState(); 2123 RefBindings B = St->get<RefBindings>(); 2124 2125 if (!B.lookup(Sym)) 2126 break; 2127 2128 FindUniqueBinding FB(Sym); 2129 StateMgr.iterBindings(St, FB); 2130 if (FB) FirstBinding = FB.getRegion(); 2131 2132 Last = N; 2133 N = N->pred_empty() ? NULL : *(N->pred_begin()); 2134 } 2135 2136 return std::make_pair(Last, FirstBinding); 2137} 2138 2139PathDiagnosticPiece* 2140CFRefReportVisitor::getEndPath(BugReporterContext &BRC, 2141 const ExplodedNode *EndN, 2142 BugReport &BR) { 2143 // Tell the BugReporterContext to report cases when the tracked symbol is 2144 // assigned to different variables, etc. 2145 BRC.addNotableSymbol(Sym); 2146 return BugReporterVisitor::getDefaultEndPath(BRC, EndN, BR); 2147} 2148 2149PathDiagnosticPiece* 2150CFRefLeakReportVisitor::getEndPath(BugReporterContext &BRC, 2151 const ExplodedNode *EndN, 2152 BugReport &BR) { 2153 2154 // Tell the BugReporterContext to report cases when the tracked symbol is 2155 // assigned to different variables, etc. 2156 BRC.addNotableSymbol(Sym); 2157 2158 // We are reporting a leak. Walk up the graph to get to the first node where 2159 // the symbol appeared, and also get the first VarDecl that tracked object 2160 // is stored to. 2161 const ExplodedNode *AllocNode = 0; 2162 const MemRegion* FirstBinding = 0; 2163 2164 llvm::tie(AllocNode, FirstBinding) = 2165 GetAllocationSite(BRC.getStateManager(), EndN, Sym); 2166 2167 SourceManager& SM = BRC.getSourceManager(); 2168 2169 // Compute an actual location for the leak. Sometimes a leak doesn't 2170 // occur at an actual statement (e.g., transition between blocks; end 2171 // of function) so we need to walk the graph and compute a real location. 2172 const ExplodedNode *LeakN = EndN; 2173 PathDiagnosticLocation L = PathDiagnosticLocation::createEndOfPath(LeakN, SM); 2174 2175 std::string sbuf; 2176 llvm::raw_string_ostream os(sbuf); 2177 2178 os << "Object leaked: "; 2179 2180 if (FirstBinding) { 2181 os << "object allocated and stored into '" 2182 << FirstBinding->getString() << '\''; 2183 } 2184 else 2185 os << "allocated object"; 2186 2187 // Get the retain count. 2188 const RefVal* RV = EndN->getState()->get<RefBindings>(Sym); 2189 2190 if (RV->getKind() == RefVal::ErrorLeakReturned) { 2191 // FIXME: Per comments in rdar://6320065, "create" only applies to CF 2192 // objects. Only "copy", "alloc", "retain" and "new" transfer ownership 2193 // to the caller for NS objects. 2194 const Decl *D = &EndN->getCodeDecl(); 2195 if (const ObjCMethodDecl *MD = dyn_cast<ObjCMethodDecl>(D)) { 2196 os << " is returned from a method whose name ('" 2197 << MD->getSelector().getAsString() 2198 << "') does not start with 'copy', 'mutableCopy', 'alloc' or 'new'." 2199 " This violates the naming convention rules" 2200 " given in the Memory Management Guide for Cocoa"; 2201 } 2202 else { 2203 const FunctionDecl *FD = cast<FunctionDecl>(D); 2204 os << " is return from a function whose name ('" 2205 << FD->getNameAsString() 2206 << "') does not contain 'Copy' or 'Create'. This violates the naming" 2207 " convention rules given the Memory Management Guide for Core" 2208 " Foundation"; 2209 } 2210 } 2211 else if (RV->getKind() == RefVal::ErrorGCLeakReturned) { 2212 ObjCMethodDecl &MD = cast<ObjCMethodDecl>(EndN->getCodeDecl()); 2213 os << " and returned from method '" << MD.getSelector().getAsString() 2214 << "' is potentially leaked when using garbage collection. Callers " 2215 "of this method do not expect a returned object with a +1 retain " 2216 "count since they expect the object to be managed by the garbage " 2217 "collector"; 2218 } 2219 else 2220 os << " is not referenced later in this execution path and has a retain " 2221 "count of +" << RV->getCount(); 2222 2223 return new PathDiagnosticEventPiece(L, os.str()); 2224} 2225 2226CFRefLeakReport::CFRefLeakReport(CFRefBug &D, const LangOptions &LOpts, 2227 bool GCEnabled, const SummaryLogTy &Log, 2228 ExplodedNode *n, SymbolRef sym, 2229 CheckerContext &Ctx) 2230: CFRefReport(D, LOpts, GCEnabled, Log, n, sym, false) { 2231 2232 // Most bug reports are cached at the location where they occurred. 2233 // With leaks, we want to unique them by the location where they were 2234 // allocated, and only report a single path. To do this, we need to find 2235 // the allocation site of a piece of tracked memory, which we do via a 2236 // call to GetAllocationSite. This will walk the ExplodedGraph backwards. 2237 // Note that this is *not* the trimmed graph; we are guaranteed, however, 2238 // that all ancestor nodes that represent the allocation site have the 2239 // same SourceLocation. 2240 const ExplodedNode *AllocNode = 0; 2241 2242 const SourceManager& SMgr = Ctx.getSourceManager(); 2243 2244 llvm::tie(AllocNode, AllocBinding) = // Set AllocBinding. 2245 GetAllocationSite(Ctx.getStateManager(), getErrorNode(), sym); 2246 2247 // Get the SourceLocation for the allocation site. 2248 ProgramPoint P = AllocNode->getLocation(); 2249 const Stmt *AllocStmt = cast<PostStmt>(P).getStmt(); 2250 Location = PathDiagnosticLocation::createBegin(AllocStmt, SMgr, 2251 n->getLocationContext()); 2252 // Fill in the description of the bug. 2253 Description.clear(); 2254 llvm::raw_string_ostream os(Description); 2255 unsigned AllocLine = SMgr.getExpansionLineNumber(AllocStmt->getLocStart()); 2256 os << "Potential leak "; 2257 if (GCEnabled) 2258 os << "(when using garbage collection) "; 2259 os << "of an object allocated on line " << AllocLine; 2260 2261 // FIXME: AllocBinding doesn't get populated for RegionStore yet. 2262 if (AllocBinding) 2263 os << " and stored into '" << AllocBinding->getString() << '\''; 2264 2265 addVisitor(new CFRefLeakReportVisitor(sym, GCEnabled, Log)); 2266} 2267 2268//===----------------------------------------------------------------------===// 2269// Main checker logic. 2270//===----------------------------------------------------------------------===// 2271 2272namespace { 2273class RetainCountChecker 2274 : public Checker< check::Bind, 2275 check::DeadSymbols, 2276 check::EndAnalysis, 2277 check::EndPath, 2278 check::PostStmt<BlockExpr>, 2279 check::PostStmt<CastExpr>, 2280 check::PostStmt<CallExpr>, 2281 check::PostStmt<CXXConstructExpr>, 2282 check::PostObjCMessage, 2283 check::PreStmt<ReturnStmt>, 2284 check::RegionChanges, 2285 eval::Assume, 2286 eval::Call > { 2287 mutable llvm::OwningPtr<CFRefBug> useAfterRelease, releaseNotOwned; 2288 mutable llvm::OwningPtr<CFRefBug> deallocGC, deallocNotOwned; 2289 mutable llvm::OwningPtr<CFRefBug> overAutorelease, returnNotOwnedForOwned; 2290 mutable llvm::OwningPtr<CFRefBug> leakWithinFunction, leakAtReturn; 2291 mutable llvm::OwningPtr<CFRefBug> leakWithinFunctionGC, leakAtReturnGC; 2292 2293 typedef llvm::DenseMap<SymbolRef, const SimpleProgramPointTag *> SymbolTagMap; 2294 2295 // This map is only used to ensure proper deletion of any allocated tags. 2296 mutable SymbolTagMap DeadSymbolTags; 2297 2298 mutable llvm::OwningPtr<RetainSummaryManager> Summaries; 2299 mutable llvm::OwningPtr<RetainSummaryManager> SummariesGC; 2300 2301 mutable ARCounts::Factory ARCountFactory; 2302 2303 mutable SummaryLogTy SummaryLog; 2304 mutable bool ShouldResetSummaryLog; 2305 2306public: 2307 RetainCountChecker() : ShouldResetSummaryLog(false) {} 2308 2309 virtual ~RetainCountChecker() { 2310 DeleteContainerSeconds(DeadSymbolTags); 2311 } 2312 2313 void checkEndAnalysis(ExplodedGraph &G, BugReporter &BR, 2314 ExprEngine &Eng) const { 2315 // FIXME: This is a hack to make sure the summary log gets cleared between 2316 // analyses of different code bodies. 2317 // 2318 // Why is this necessary? Because a checker's lifetime is tied to a 2319 // translation unit, but an ExplodedGraph's lifetime is just a code body. 2320 // Once in a blue moon, a new ExplodedNode will have the same address as an 2321 // old one with an associated summary, and the bug report visitor gets very 2322 // confused. (To make things worse, the summary lifetime is currently also 2323 // tied to a code body, so we get a crash instead of incorrect results.) 2324 // 2325 // Why is this a bad solution? Because if the lifetime of the ExplodedGraph 2326 // changes, things will start going wrong again. Really the lifetime of this 2327 // log needs to be tied to either the specific nodes in it or the entire 2328 // ExplodedGraph, not to a specific part of the code being analyzed. 2329 // 2330 // (Also, having stateful local data means that the same checker can't be 2331 // used from multiple threads, but a lot of checkers have incorrect 2332 // assumptions about that anyway. So that wasn't a priority at the time of 2333 // this fix.) 2334 // 2335 // This happens at the end of analysis, but bug reports are emitted /after/ 2336 // this point. So we can't just clear the summary log now. Instead, we mark 2337 // that the next time we access the summary log, it should be cleared. 2338 2339 // If we never reset the summary log during /this/ code body analysis, 2340 // there were no new summaries. There might still have been summaries from 2341 // the /last/ analysis, so clear them out to make sure the bug report 2342 // visitors don't get confused. 2343 if (ShouldResetSummaryLog) 2344 SummaryLog.clear(); 2345 2346 ShouldResetSummaryLog = !SummaryLog.empty(); 2347 } 2348 2349 CFRefBug *getLeakWithinFunctionBug(const LangOptions &LOpts, 2350 bool GCEnabled) const { 2351 if (GCEnabled) { 2352 if (!leakWithinFunctionGC) 2353 leakWithinFunctionGC.reset(new LeakWithinFunction("Leak of object when " 2354 "using garbage " 2355 "collection")); 2356 return leakWithinFunctionGC.get(); 2357 } else { 2358 if (!leakWithinFunction) { 2359 if (LOpts.getGC() == LangOptions::HybridGC) { 2360 leakWithinFunction.reset(new LeakWithinFunction("Leak of object when " 2361 "not using garbage " 2362 "collection (GC) in " 2363 "dual GC/non-GC " 2364 "code")); 2365 } else { 2366 leakWithinFunction.reset(new LeakWithinFunction("Leak")); 2367 } 2368 } 2369 return leakWithinFunction.get(); 2370 } 2371 } 2372 2373 CFRefBug *getLeakAtReturnBug(const LangOptions &LOpts, bool GCEnabled) const { 2374 if (GCEnabled) { 2375 if (!leakAtReturnGC) 2376 leakAtReturnGC.reset(new LeakAtReturn("Leak of returned object when " 2377 "using garbage collection")); 2378 return leakAtReturnGC.get(); 2379 } else { 2380 if (!leakAtReturn) { 2381 if (LOpts.getGC() == LangOptions::HybridGC) { 2382 leakAtReturn.reset(new LeakAtReturn("Leak of returned object when " 2383 "not using garbage collection " 2384 "(GC) in dual GC/non-GC code")); 2385 } else { 2386 leakAtReturn.reset(new LeakAtReturn("Leak of returned object")); 2387 } 2388 } 2389 return leakAtReturn.get(); 2390 } 2391 } 2392 2393 RetainSummaryManager &getSummaryManager(ASTContext &Ctx, 2394 bool GCEnabled) const { 2395 // FIXME: We don't support ARC being turned on and off during one analysis. 2396 // (nor, for that matter, do we support changing ASTContexts) 2397 bool ARCEnabled = (bool)Ctx.getLangOptions().ObjCAutoRefCount; 2398 if (GCEnabled) { 2399 if (!SummariesGC) 2400 SummariesGC.reset(new RetainSummaryManager(Ctx, true, ARCEnabled)); 2401 else 2402 assert(SummariesGC->isARCEnabled() == ARCEnabled); 2403 return *SummariesGC; 2404 } else { 2405 if (!Summaries) 2406 Summaries.reset(new RetainSummaryManager(Ctx, false, ARCEnabled)); 2407 else 2408 assert(Summaries->isARCEnabled() == ARCEnabled); 2409 return *Summaries; 2410 } 2411 } 2412 2413 RetainSummaryManager &getSummaryManager(CheckerContext &C) const { 2414 return getSummaryManager(C.getASTContext(), C.isObjCGCEnabled()); 2415 } 2416 2417 void printState(raw_ostream &Out, const ProgramState *State, 2418 const char *NL, const char *Sep) const; 2419 2420 void checkBind(SVal loc, SVal val, const Stmt *S, CheckerContext &C) const; 2421 void checkPostStmt(const BlockExpr *BE, CheckerContext &C) const; 2422 void checkPostStmt(const CastExpr *CE, CheckerContext &C) const; 2423 2424 void checkPostStmt(const CallExpr *CE, CheckerContext &C) const; 2425 void checkPostStmt(const CXXConstructExpr *CE, CheckerContext &C) const; 2426 void checkPostObjCMessage(const ObjCMessage &Msg, CheckerContext &C) const; 2427 void checkSummary(const RetainSummary &Summ, const CallOrObjCMessage &Call, 2428 CheckerContext &C) const; 2429 2430 bool evalCall(const CallExpr *CE, CheckerContext &C) const; 2431 2432 const ProgramState *evalAssume(const ProgramState *state, SVal Cond, 2433 bool Assumption) const; 2434 2435 const ProgramState * 2436 checkRegionChanges(const ProgramState *state, 2437 const StoreManager::InvalidatedSymbols *invalidated, 2438 ArrayRef<const MemRegion *> ExplicitRegions, 2439 ArrayRef<const MemRegion *> Regions) const; 2440 2441 bool wantsRegionChangeUpdate(const ProgramState *state) const { 2442 return true; 2443 } 2444 2445 void checkPreStmt(const ReturnStmt *S, CheckerContext &C) const; 2446 void checkReturnWithRetEffect(const ReturnStmt *S, CheckerContext &C, 2447 ExplodedNode *Pred, RetEffect RE, RefVal X, 2448 SymbolRef Sym, const ProgramState *state) const; 2449 2450 void checkDeadSymbols(SymbolReaper &SymReaper, CheckerContext &C) const; 2451 void checkEndPath(CheckerContext &C) const; 2452 2453 const ProgramState *updateSymbol(const ProgramState *state, SymbolRef sym, 2454 RefVal V, ArgEffect E, RefVal::Kind &hasErr, 2455 CheckerContext &C) const; 2456 2457 void processNonLeakError(const ProgramState *St, SourceRange ErrorRange, 2458 RefVal::Kind ErrorKind, SymbolRef Sym, 2459 CheckerContext &C) const; 2460 2461 const ProgramPointTag *getDeadSymbolTag(SymbolRef sym) const; 2462 2463 const ProgramState *handleSymbolDeath(const ProgramState *state, 2464 SymbolRef sid, RefVal V, 2465 SmallVectorImpl<SymbolRef> &Leaked) const; 2466 2467 std::pair<ExplodedNode *, const ProgramState *> 2468 handleAutoreleaseCounts(const ProgramState *state, 2469 GenericNodeBuilderRefCount Bd, ExplodedNode *Pred, 2470 CheckerContext &Ctx, SymbolRef Sym, RefVal V) const; 2471 2472 ExplodedNode *processLeaks(const ProgramState *state, 2473 SmallVectorImpl<SymbolRef> &Leaked, 2474 GenericNodeBuilderRefCount &Builder, 2475 CheckerContext &Ctx, 2476 ExplodedNode *Pred = 0) const; 2477}; 2478} // end anonymous namespace 2479 2480namespace { 2481class StopTrackingCallback : public SymbolVisitor { 2482 const ProgramState *state; 2483public: 2484 StopTrackingCallback(const ProgramState *st) : state(st) {} 2485 const ProgramState *getState() const { return state; } 2486 2487 bool VisitSymbol(SymbolRef sym) { 2488 state = state->remove<RefBindings>(sym); 2489 return true; 2490 } 2491}; 2492} // end anonymous namespace 2493 2494//===----------------------------------------------------------------------===// 2495// Handle statements that may have an effect on refcounts. 2496//===----------------------------------------------------------------------===// 2497 2498void RetainCountChecker::checkPostStmt(const BlockExpr *BE, 2499 CheckerContext &C) const { 2500 2501 // Scan the BlockDecRefExprs for any object the retain count checker 2502 // may be tracking. 2503 if (!BE->getBlockDecl()->hasCaptures()) 2504 return; 2505 2506 const ProgramState *state = C.getState(); 2507 const BlockDataRegion *R = 2508 cast<BlockDataRegion>(state->getSVal(BE).getAsRegion()); 2509 2510 BlockDataRegion::referenced_vars_iterator I = R->referenced_vars_begin(), 2511 E = R->referenced_vars_end(); 2512 2513 if (I == E) 2514 return; 2515 2516 // FIXME: For now we invalidate the tracking of all symbols passed to blocks 2517 // via captured variables, even though captured variables result in a copy 2518 // and in implicit increment/decrement of a retain count. 2519 SmallVector<const MemRegion*, 10> Regions; 2520 const LocationContext *LC = C.getLocationContext(); 2521 MemRegionManager &MemMgr = C.getSValBuilder().getRegionManager(); 2522 2523 for ( ; I != E; ++I) { 2524 const VarRegion *VR = *I; 2525 if (VR->getSuperRegion() == R) { 2526 VR = MemMgr.getVarRegion(VR->getDecl(), LC); 2527 } 2528 Regions.push_back(VR); 2529 } 2530 2531 state = 2532 state->scanReachableSymbols<StopTrackingCallback>(Regions.data(), 2533 Regions.data() + Regions.size()).getState(); 2534 C.addTransition(state); 2535} 2536 2537void RetainCountChecker::checkPostStmt(const CastExpr *CE, 2538 CheckerContext &C) const { 2539 const ObjCBridgedCastExpr *BE = dyn_cast<ObjCBridgedCastExpr>(CE); 2540 if (!BE) 2541 return; 2542 2543 ArgEffect AE = IncRef; 2544 2545 switch (BE->getBridgeKind()) { 2546 case clang::OBC_Bridge: 2547 // Do nothing. 2548 return; 2549 case clang::OBC_BridgeRetained: 2550 AE = IncRef; 2551 break; 2552 case clang::OBC_BridgeTransfer: 2553 AE = DecRefBridgedTransfered; 2554 break; 2555 } 2556 2557 const ProgramState *state = C.getState(); 2558 SymbolRef Sym = state->getSVal(CE).getAsLocSymbol(); 2559 if (!Sym) 2560 return; 2561 const RefVal* T = state->get<RefBindings>(Sym); 2562 if (!T) 2563 return; 2564 2565 RefVal::Kind hasErr = (RefVal::Kind) 0; 2566 state = updateSymbol(state, Sym, *T, AE, hasErr, C); 2567 2568 if (hasErr) { 2569 // FIXME: If we get an error during a bridge cast, should we report it? 2570 // Should we assert that there is no error? 2571 return; 2572 } 2573 2574 C.addTransition(state); 2575} 2576 2577void RetainCountChecker::checkPostStmt(const CallExpr *CE, 2578 CheckerContext &C) const { 2579 // Get the callee. 2580 const ProgramState *state = C.getState(); 2581 const Expr *Callee = CE->getCallee(); 2582 SVal L = state->getSVal(Callee); 2583 2584 RetainSummaryManager &Summaries = getSummaryManager(C); 2585 const RetainSummary *Summ = 0; 2586 2587 // FIXME: Better support for blocks. For now we stop tracking anything 2588 // that is passed to blocks. 2589 // FIXME: Need to handle variables that are "captured" by the block. 2590 if (dyn_cast_or_null<BlockDataRegion>(L.getAsRegion())) { 2591 Summ = Summaries.getPersistentStopSummary(); 2592 } else if (const FunctionDecl *FD = L.getAsFunctionDecl()) { 2593 Summ = Summaries.getSummary(FD); 2594 } else if (const CXXMemberCallExpr *me = dyn_cast<CXXMemberCallExpr>(CE)) { 2595 if (const CXXMethodDecl *MD = me->getMethodDecl()) 2596 Summ = Summaries.getSummary(MD); 2597 } 2598 2599 if (!Summ) 2600 Summ = Summaries.getDefaultSummary(); 2601 2602 checkSummary(*Summ, CallOrObjCMessage(CE, state), C); 2603} 2604 2605void RetainCountChecker::checkPostStmt(const CXXConstructExpr *CE, 2606 CheckerContext &C) const { 2607 const CXXConstructorDecl *Ctor = CE->getConstructor(); 2608 if (!Ctor) 2609 return; 2610 2611 RetainSummaryManager &Summaries = getSummaryManager(C); 2612 const RetainSummary *Summ = Summaries.getSummary(Ctor); 2613 2614 // If we didn't get a summary, this constructor doesn't affect retain counts. 2615 if (!Summ) 2616 return; 2617 2618 const ProgramState *state = C.getState(); 2619 checkSummary(*Summ, CallOrObjCMessage(CE, state), C); 2620} 2621 2622void RetainCountChecker::checkPostObjCMessage(const ObjCMessage &Msg, 2623 CheckerContext &C) const { 2624 const ProgramState *state = C.getState(); 2625 2626 RetainSummaryManager &Summaries = getSummaryManager(C); 2627 2628 const RetainSummary *Summ; 2629 if (Msg.isInstanceMessage()) { 2630 const LocationContext *LC = C.getLocationContext(); 2631 Summ = Summaries.getInstanceMethodSummary(Msg, state, LC); 2632 } else { 2633 Summ = Summaries.getClassMethodSummary(Msg); 2634 } 2635 2636 // If we didn't get a summary, this message doesn't affect retain counts. 2637 if (!Summ) 2638 return; 2639 2640 checkSummary(*Summ, CallOrObjCMessage(Msg, state), C); 2641} 2642 2643/// GetReturnType - Used to get the return type of a message expression or 2644/// function call with the intention of affixing that type to a tracked symbol. 2645/// While the the return type can be queried directly from RetEx, when 2646/// invoking class methods we augment to the return type to be that of 2647/// a pointer to the class (as opposed it just being id). 2648// FIXME: We may be able to do this with related result types instead. 2649// This function is probably overestimating. 2650static QualType GetReturnType(const Expr *RetE, ASTContext &Ctx) { 2651 QualType RetTy = RetE->getType(); 2652 // If RetE is not a message expression just return its type. 2653 // If RetE is a message expression, return its types if it is something 2654 /// more specific than id. 2655 if (const ObjCMessageExpr *ME = dyn_cast<ObjCMessageExpr>(RetE)) 2656 if (const ObjCObjectPointerType *PT = RetTy->getAs<ObjCObjectPointerType>()) 2657 if (PT->isObjCQualifiedIdType() || PT->isObjCIdType() || 2658 PT->isObjCClassType()) { 2659 // At this point we know the return type of the message expression is 2660 // id, id<...>, or Class. If we have an ObjCInterfaceDecl, we know this 2661 // is a call to a class method whose type we can resolve. In such 2662 // cases, promote the return type to XXX* (where XXX is the class). 2663 const ObjCInterfaceDecl *D = ME->getReceiverInterface(); 2664 return !D ? RetTy : 2665 Ctx.getObjCObjectPointerType(Ctx.getObjCInterfaceType(D)); 2666 } 2667 2668 return RetTy; 2669} 2670 2671void RetainCountChecker::checkSummary(const RetainSummary &Summ, 2672 const CallOrObjCMessage &CallOrMsg, 2673 CheckerContext &C) const { 2674 const ProgramState *state = C.getState(); 2675 2676 // Evaluate the effect of the arguments. 2677 RefVal::Kind hasErr = (RefVal::Kind) 0; 2678 SourceRange ErrorRange; 2679 SymbolRef ErrorSym = 0; 2680 2681 for (unsigned idx = 0, e = CallOrMsg.getNumArgs(); idx != e; ++idx) { 2682 SVal V = CallOrMsg.getArgSVal(idx); 2683 2684 if (SymbolRef Sym = V.getAsLocSymbol()) { 2685 if (RefBindings::data_type *T = state->get<RefBindings>(Sym)) { 2686 state = updateSymbol(state, Sym, *T, Summ.getArg(idx), hasErr, C); 2687 if (hasErr) { 2688 ErrorRange = CallOrMsg.getArgSourceRange(idx); 2689 ErrorSym = Sym; 2690 break; 2691 } 2692 } 2693 } 2694 } 2695 2696 // Evaluate the effect on the message receiver. 2697 bool ReceiverIsTracked = false; 2698 if (!hasErr && CallOrMsg.isObjCMessage()) { 2699 const LocationContext *LC = C.getLocationContext(); 2700 SVal Receiver = CallOrMsg.getInstanceMessageReceiver(LC); 2701 if (SymbolRef Sym = Receiver.getAsLocSymbol()) { 2702 if (const RefVal *T = state->get<RefBindings>(Sym)) { 2703 ReceiverIsTracked = true; 2704 state = updateSymbol(state, Sym, *T, Summ.getReceiverEffect(), 2705 hasErr, C); 2706 if (hasErr) { 2707 ErrorRange = CallOrMsg.getReceiverSourceRange(); 2708 ErrorSym = Sym; 2709 } 2710 } 2711 } 2712 } 2713 2714 // Process any errors. 2715 if (hasErr) { 2716 processNonLeakError(state, ErrorRange, hasErr, ErrorSym, C); 2717 return; 2718 } 2719 2720 // Consult the summary for the return value. 2721 RetEffect RE = Summ.getRetEffect(); 2722 2723 if (RE.getKind() == RetEffect::OwnedWhenTrackedReceiver) { 2724 if (ReceiverIsTracked) 2725 RE = getSummaryManager(C).getObjAllocRetEffect(); 2726 else 2727 RE = RetEffect::MakeNoRet(); 2728 } 2729 2730 switch (RE.getKind()) { 2731 default: 2732 llvm_unreachable("Unhandled RetEffect."); break; 2733 2734 case RetEffect::NoRet: 2735 // No work necessary. 2736 break; 2737 2738 case RetEffect::OwnedAllocatedSymbol: 2739 case RetEffect::OwnedSymbol: { 2740 SymbolRef Sym = state->getSVal(CallOrMsg.getOriginExpr()).getAsSymbol(); 2741 if (!Sym) 2742 break; 2743 2744 // Use the result type from callOrMsg as it automatically adjusts 2745 // for methods/functions that return references. 2746 QualType ResultTy = CallOrMsg.getResultType(C.getASTContext()); 2747 state = state->set<RefBindings>(Sym, RefVal::makeOwned(RE.getObjKind(), 2748 ResultTy)); 2749 2750 // FIXME: Add a flag to the checker where allocations are assumed to 2751 // *not* fail. (The code below is out-of-date, though.) 2752#if 0 2753 if (RE.getKind() == RetEffect::OwnedAllocatedSymbol) { 2754 bool isFeasible; 2755 state = state.assume(loc::SymbolVal(Sym), true, isFeasible); 2756 assert(isFeasible && "Cannot assume fresh symbol is non-null."); 2757 } 2758#endif 2759 2760 break; 2761 } 2762 2763 case RetEffect::GCNotOwnedSymbol: 2764 case RetEffect::ARCNotOwnedSymbol: 2765 case RetEffect::NotOwnedSymbol: { 2766 const Expr *Ex = CallOrMsg.getOriginExpr(); 2767 SymbolRef Sym = state->getSVal(Ex).getAsSymbol(); 2768 if (!Sym) 2769 break; 2770 2771 // Use GetReturnType in order to give [NSFoo alloc] the type NSFoo *. 2772 QualType ResultTy = GetReturnType(Ex, C.getASTContext()); 2773 state = state->set<RefBindings>(Sym, RefVal::makeNotOwned(RE.getObjKind(), 2774 ResultTy)); 2775 break; 2776 } 2777 } 2778 2779 // This check is actually necessary; otherwise the statement builder thinks 2780 // we've hit a previously-found path. 2781 // Normally addTransition takes care of this, but we want the node pointer. 2782 ExplodedNode *NewNode; 2783 if (state == C.getState()) { 2784 NewNode = C.getPredecessor(); 2785 } else { 2786 NewNode = C.addTransition(state); 2787 } 2788 2789 // Annotate the node with summary we used. 2790 if (NewNode) { 2791 // FIXME: This is ugly. See checkEndAnalysis for why it's necessary. 2792 if (ShouldResetSummaryLog) { 2793 SummaryLog.clear(); 2794 ShouldResetSummaryLog = false; 2795 } 2796 SummaryLog[NewNode] = &Summ; 2797 } 2798} 2799 2800 2801const ProgramState * 2802RetainCountChecker::updateSymbol(const ProgramState *state, SymbolRef sym, 2803 RefVal V, ArgEffect E, RefVal::Kind &hasErr, 2804 CheckerContext &C) const { 2805 // In GC mode [... release] and [... retain] do nothing. 2806 // In ARC mode they shouldn't exist at all, but we just ignore them. 2807 bool IgnoreRetainMsg = C.isObjCGCEnabled(); 2808 if (!IgnoreRetainMsg) 2809 IgnoreRetainMsg = (bool)C.getASTContext().getLangOptions().ObjCAutoRefCount; 2810 2811 switch (E) { 2812 default: break; 2813 case IncRefMsg: E = IgnoreRetainMsg ? DoNothing : IncRef; break; 2814 case DecRefMsg: E = IgnoreRetainMsg ? DoNothing : DecRef; break; 2815 case MakeCollectable: E = C.isObjCGCEnabled() ? DecRef : DoNothing; break; 2816 case NewAutoreleasePool: E = C.isObjCGCEnabled() ? DoNothing : 2817 NewAutoreleasePool; break; 2818 } 2819 2820 // Handle all use-after-releases. 2821 if (!C.isObjCGCEnabled() && V.getKind() == RefVal::Released) { 2822 V = V ^ RefVal::ErrorUseAfterRelease; 2823 hasErr = V.getKind(); 2824 return state->set<RefBindings>(sym, V); 2825 } 2826 2827 switch (E) { 2828 case DecRefMsg: 2829 case IncRefMsg: 2830 case MakeCollectable: 2831 llvm_unreachable("DecRefMsg/IncRefMsg/MakeCollectable already converted"); 2832 return state; 2833 2834 case Dealloc: 2835 // Any use of -dealloc in GC is *bad*. 2836 if (C.isObjCGCEnabled()) { 2837 V = V ^ RefVal::ErrorDeallocGC; 2838 hasErr = V.getKind(); 2839 break; 2840 } 2841 2842 switch (V.getKind()) { 2843 default: 2844 llvm_unreachable("Invalid RefVal state for an explicit dealloc."); 2845 break; 2846 case RefVal::Owned: 2847 // The object immediately transitions to the released state. 2848 V = V ^ RefVal::Released; 2849 V.clearCounts(); 2850 return state->set<RefBindings>(sym, V); 2851 case RefVal::NotOwned: 2852 V = V ^ RefVal::ErrorDeallocNotOwned; 2853 hasErr = V.getKind(); 2854 break; 2855 } 2856 break; 2857 2858 case NewAutoreleasePool: 2859 assert(!C.isObjCGCEnabled()); 2860 return state->add<AutoreleaseStack>(sym); 2861 2862 case MayEscape: 2863 if (V.getKind() == RefVal::Owned) { 2864 V = V ^ RefVal::NotOwned; 2865 break; 2866 } 2867 2868 // Fall-through. 2869 2870 case DoNothing: 2871 return state; 2872 2873 case Autorelease: 2874 if (C.isObjCGCEnabled()) 2875 return state; 2876 2877 // Update the autorelease counts. 2878 state = SendAutorelease(state, ARCountFactory, sym); 2879 V = V.autorelease(); 2880 break; 2881 2882 case StopTracking: 2883 return state->remove<RefBindings>(sym); 2884 2885 case IncRef: 2886 switch (V.getKind()) { 2887 default: 2888 llvm_unreachable("Invalid RefVal state for a retain."); 2889 break; 2890 case RefVal::Owned: 2891 case RefVal::NotOwned: 2892 V = V + 1; 2893 break; 2894 case RefVal::Released: 2895 // Non-GC cases are handled above. 2896 assert(C.isObjCGCEnabled()); 2897 V = (V ^ RefVal::Owned) + 1; 2898 break; 2899 } 2900 break; 2901 2902 case SelfOwn: 2903 V = V ^ RefVal::NotOwned; 2904 // Fall-through. 2905 case DecRef: 2906 case DecRefBridgedTransfered: 2907 switch (V.getKind()) { 2908 default: 2909 // case 'RefVal::Released' handled above. 2910 llvm_unreachable("Invalid RefVal state for a release."); 2911 break; 2912 2913 case RefVal::Owned: 2914 assert(V.getCount() > 0); 2915 if (V.getCount() == 1) 2916 V = V ^ (E == DecRefBridgedTransfered ? 2917 RefVal::NotOwned : RefVal::Released); 2918 V = V - 1; 2919 break; 2920 2921 case RefVal::NotOwned: 2922 if (V.getCount() > 0) 2923 V = V - 1; 2924 else { 2925 V = V ^ RefVal::ErrorReleaseNotOwned; 2926 hasErr = V.getKind(); 2927 } 2928 break; 2929 2930 case RefVal::Released: 2931 // Non-GC cases are handled above. 2932 assert(C.isObjCGCEnabled()); 2933 V = V ^ RefVal::ErrorUseAfterRelease; 2934 hasErr = V.getKind(); 2935 break; 2936 } 2937 break; 2938 } 2939 return state->set<RefBindings>(sym, V); 2940} 2941 2942void RetainCountChecker::processNonLeakError(const ProgramState *St, 2943 SourceRange ErrorRange, 2944 RefVal::Kind ErrorKind, 2945 SymbolRef Sym, 2946 CheckerContext &C) const { 2947 ExplodedNode *N = C.generateSink(St); 2948 if (!N) 2949 return; 2950 2951 CFRefBug *BT; 2952 switch (ErrorKind) { 2953 default: 2954 llvm_unreachable("Unhandled error."); 2955 return; 2956 case RefVal::ErrorUseAfterRelease: 2957 if (!useAfterRelease) 2958 useAfterRelease.reset(new UseAfterRelease()); 2959 BT = &*useAfterRelease; 2960 break; 2961 case RefVal::ErrorReleaseNotOwned: 2962 if (!releaseNotOwned) 2963 releaseNotOwned.reset(new BadRelease()); 2964 BT = &*releaseNotOwned; 2965 break; 2966 case RefVal::ErrorDeallocGC: 2967 if (!deallocGC) 2968 deallocGC.reset(new DeallocGC()); 2969 BT = &*deallocGC; 2970 break; 2971 case RefVal::ErrorDeallocNotOwned: 2972 if (!deallocNotOwned) 2973 deallocNotOwned.reset(new DeallocNotOwned()); 2974 BT = &*deallocNotOwned; 2975 break; 2976 } 2977 2978 assert(BT); 2979 CFRefReport *report = new CFRefReport(*BT, C.getASTContext().getLangOptions(), 2980 C.isObjCGCEnabled(), SummaryLog, 2981 N, Sym); 2982 report->addRange(ErrorRange); 2983 C.EmitReport(report); 2984} 2985 2986//===----------------------------------------------------------------------===// 2987// Handle the return values of retain-count-related functions. 2988//===----------------------------------------------------------------------===// 2989 2990bool RetainCountChecker::evalCall(const CallExpr *CE, CheckerContext &C) const { 2991 // Get the callee. We're only interested in simple C functions. 2992 const ProgramState *state = C.getState(); 2993 const FunctionDecl *FD = C.getCalleeDecl(CE); 2994 if (!FD) 2995 return false; 2996 2997 IdentifierInfo *II = FD->getIdentifier(); 2998 if (!II) 2999 return false; 3000 3001 // For now, we're only handling the functions that return aliases of their 3002 // arguments: CFRetain and CFMakeCollectable (and their families). 3003 // Eventually we should add other functions we can model entirely, 3004 // such as CFRelease, which don't invalidate their arguments or globals. 3005 if (CE->getNumArgs() != 1) 3006 return false; 3007 3008 // Get the name of the function. 3009 StringRef FName = II->getName(); 3010 FName = FName.substr(FName.find_first_not_of('_')); 3011 3012 // See if it's one of the specific functions we know how to eval. 3013 bool canEval = false; 3014 3015 QualType ResultTy = CE->getCallReturnType(); 3016 if (ResultTy->isObjCIdType()) { 3017 // Handle: id NSMakeCollectable(CFTypeRef) 3018 canEval = II->isStr("NSMakeCollectable"); 3019 } else if (ResultTy->isPointerType()) { 3020 // Handle: (CF|CG)Retain 3021 // CFMakeCollectable 3022 // It's okay to be a little sloppy here (CGMakeCollectable doesn't exist). 3023 if (cocoa::isRefType(ResultTy, "CF", FName) || 3024 cocoa::isRefType(ResultTy, "CG", FName)) { 3025 canEval = isRetain(FD, FName) || isMakeCollectable(FD, FName); 3026 } 3027 } 3028 3029 if (!canEval) 3030 return false; 3031 3032 // Bind the return value. 3033 SVal RetVal = state->getSVal(CE->getArg(0)); 3034 if (RetVal.isUnknown()) { 3035 // If the receiver is unknown, conjure a return value. 3036 SValBuilder &SVB = C.getSValBuilder(); 3037 unsigned Count = C.getCurrentBlockCount(); 3038 SVal RetVal = SVB.getConjuredSymbolVal(0, CE, ResultTy, Count); 3039 } 3040 state = state->BindExpr(CE, RetVal, false); 3041 3042 // FIXME: This should not be necessary, but otherwise the argument seems to be 3043 // considered alive during the next statement. 3044 if (const MemRegion *ArgRegion = RetVal.getAsRegion()) { 3045 // Save the refcount status of the argument. 3046 SymbolRef Sym = RetVal.getAsLocSymbol(); 3047 RefBindings::data_type *Binding = 0; 3048 if (Sym) 3049 Binding = state->get<RefBindings>(Sym); 3050 3051 // Invalidate the argument region. 3052 unsigned Count = C.getCurrentBlockCount(); 3053 state = state->invalidateRegions(ArgRegion, CE, Count); 3054 3055 // Restore the refcount status of the argument. 3056 if (Binding) 3057 state = state->set<RefBindings>(Sym, *Binding); 3058 } 3059 3060 C.addTransition(state); 3061 return true; 3062} 3063 3064//===----------------------------------------------------------------------===// 3065// Handle return statements. 3066//===----------------------------------------------------------------------===// 3067 3068void RetainCountChecker::checkPreStmt(const ReturnStmt *S, 3069 CheckerContext &C) const { 3070 const Expr *RetE = S->getRetValue(); 3071 if (!RetE) 3072 return; 3073 3074 const ProgramState *state = C.getState(); 3075 SymbolRef Sym = state->getSValAsScalarOrLoc(RetE).getAsLocSymbol(); 3076 if (!Sym) 3077 return; 3078 3079 // Get the reference count binding (if any). 3080 const RefVal *T = state->get<RefBindings>(Sym); 3081 if (!T) 3082 return; 3083 3084 // Change the reference count. 3085 RefVal X = *T; 3086 3087 switch (X.getKind()) { 3088 case RefVal::Owned: { 3089 unsigned cnt = X.getCount(); 3090 assert(cnt > 0); 3091 X.setCount(cnt - 1); 3092 X = X ^ RefVal::ReturnedOwned; 3093 break; 3094 } 3095 3096 case RefVal::NotOwned: { 3097 unsigned cnt = X.getCount(); 3098 if (cnt) { 3099 X.setCount(cnt - 1); 3100 X = X ^ RefVal::ReturnedOwned; 3101 } 3102 else { 3103 X = X ^ RefVal::ReturnedNotOwned; 3104 } 3105 break; 3106 } 3107 3108 default: 3109 return; 3110 } 3111 3112 // Update the binding. 3113 state = state->set<RefBindings>(Sym, X); 3114 ExplodedNode *Pred = C.addTransition(state); 3115 3116 // At this point we have updated the state properly. 3117 // Everything after this is merely checking to see if the return value has 3118 // been over- or under-retained. 3119 3120 // Did we cache out? 3121 if (!Pred) 3122 return; 3123 3124 // Update the autorelease counts. 3125 static SimpleProgramPointTag 3126 AutoreleaseTag("RetainCountChecker : Autorelease"); 3127 GenericNodeBuilderRefCount Bd(C, &AutoreleaseTag); 3128 llvm::tie(Pred, state) = handleAutoreleaseCounts(state, Bd, Pred, C, Sym, X); 3129 3130 // Did we cache out? 3131 if (!Pred) 3132 return; 3133 3134 // Get the updated binding. 3135 T = state->get<RefBindings>(Sym); 3136 assert(T); 3137 X = *T; 3138 3139 // Consult the summary of the enclosing method. 3140 RetainSummaryManager &Summaries = getSummaryManager(C); 3141 const Decl *CD = &Pred->getCodeDecl(); 3142 3143 if (const ObjCMethodDecl *MD = dyn_cast<ObjCMethodDecl>(CD)) { 3144 // Unlike regular functions, /all/ ObjC methods are assumed to always 3145 // follow Cocoa retain-count conventions, not just those with special 3146 // names or attributes. 3147 const RetainSummary *Summ = Summaries.getMethodSummary(MD); 3148 RetEffect RE = Summ ? Summ->getRetEffect() : RetEffect::MakeNoRet(); 3149 checkReturnWithRetEffect(S, C, Pred, RE, X, Sym, state); 3150 } 3151 3152 if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(CD)) { 3153 if (!isa<CXXMethodDecl>(FD)) 3154 if (const RetainSummary *Summ = Summaries.getSummary(FD)) 3155 checkReturnWithRetEffect(S, C, Pred, Summ->getRetEffect(), X, 3156 Sym, state); 3157 } 3158} 3159 3160void RetainCountChecker::checkReturnWithRetEffect(const ReturnStmt *S, 3161 CheckerContext &C, 3162 ExplodedNode *Pred, 3163 RetEffect RE, RefVal X, 3164 SymbolRef Sym, 3165 const ProgramState *state) const { 3166 // Any leaks or other errors? 3167 if (X.isReturnedOwned() && X.getCount() == 0) { 3168 if (RE.getKind() != RetEffect::NoRet) { 3169 bool hasError = false; 3170 if (C.isObjCGCEnabled() && RE.getObjKind() == RetEffect::ObjC) { 3171 // Things are more complicated with garbage collection. If the 3172 // returned object is suppose to be an Objective-C object, we have 3173 // a leak (as the caller expects a GC'ed object) because no 3174 // method should return ownership unless it returns a CF object. 3175 hasError = true; 3176 X = X ^ RefVal::ErrorGCLeakReturned; 3177 } 3178 else if (!RE.isOwned()) { 3179 // Either we are using GC and the returned object is a CF type 3180 // or we aren't using GC. In either case, we expect that the 3181 // enclosing method is expected to return ownership. 3182 hasError = true; 3183 X = X ^ RefVal::ErrorLeakReturned; 3184 } 3185 3186 if (hasError) { 3187 // Generate an error node. 3188 state = state->set<RefBindings>(Sym, X); 3189 3190 static SimpleProgramPointTag 3191 ReturnOwnLeakTag("RetainCountChecker : ReturnsOwnLeak"); 3192 ExplodedNode *N = C.addTransition(state, Pred, &ReturnOwnLeakTag); 3193 if (N) { 3194 const LangOptions &LOpts = C.getASTContext().getLangOptions(); 3195 bool GCEnabled = C.isObjCGCEnabled(); 3196 CFRefReport *report = 3197 new CFRefLeakReport(*getLeakAtReturnBug(LOpts, GCEnabled), 3198 LOpts, GCEnabled, SummaryLog, 3199 N, Sym, C); 3200 C.EmitReport(report); 3201 } 3202 } 3203 } 3204 } else if (X.isReturnedNotOwned()) { 3205 if (RE.isOwned()) { 3206 // Trying to return a not owned object to a caller expecting an 3207 // owned object. 3208 state = state->set<RefBindings>(Sym, X ^ RefVal::ErrorReturnedNotOwned); 3209 3210 static SimpleProgramPointTag 3211 ReturnNotOwnedTag("RetainCountChecker : ReturnNotOwnedForOwned"); 3212 ExplodedNode *N = C.addTransition(state, Pred, &ReturnNotOwnedTag); 3213 if (N) { 3214 if (!returnNotOwnedForOwned) 3215 returnNotOwnedForOwned.reset(new ReturnedNotOwnedForOwned()); 3216 3217 CFRefReport *report = 3218 new CFRefReport(*returnNotOwnedForOwned, 3219 C.getASTContext().getLangOptions(), 3220 C.isObjCGCEnabled(), SummaryLog, N, Sym); 3221 C.EmitReport(report); 3222 } 3223 } 3224 } 3225} 3226 3227//===----------------------------------------------------------------------===// 3228// Check various ways a symbol can be invalidated. 3229//===----------------------------------------------------------------------===// 3230 3231void RetainCountChecker::checkBind(SVal loc, SVal val, const Stmt *S, 3232 CheckerContext &C) const { 3233 // Are we storing to something that causes the value to "escape"? 3234 bool escapes = true; 3235 3236 // A value escapes in three possible cases (this may change): 3237 // 3238 // (1) we are binding to something that is not a memory region. 3239 // (2) we are binding to a memregion that does not have stack storage 3240 // (3) we are binding to a memregion with stack storage that the store 3241 // does not understand. 3242 const ProgramState *state = C.getState(); 3243 3244 if (loc::MemRegionVal *regionLoc = dyn_cast<loc::MemRegionVal>(&loc)) { 3245 escapes = !regionLoc->getRegion()->hasStackStorage(); 3246 3247 if (!escapes) { 3248 // To test (3), generate a new state with the binding added. If it is 3249 // the same state, then it escapes (since the store cannot represent 3250 // the binding). 3251 escapes = (state == (state->bindLoc(*regionLoc, val))); 3252 } 3253 } 3254 3255 // If our store can represent the binding and we aren't storing to something 3256 // that doesn't have local storage then just return and have the simulation 3257 // state continue as is. 3258 if (!escapes) 3259 return; 3260 3261 // Otherwise, find all symbols referenced by 'val' that we are tracking 3262 // and stop tracking them. 3263 state = state->scanReachableSymbols<StopTrackingCallback>(val).getState(); 3264 C.addTransition(state); 3265} 3266 3267const ProgramState *RetainCountChecker::evalAssume(const ProgramState *state, 3268 SVal Cond, 3269 bool Assumption) const { 3270 3271 // FIXME: We may add to the interface of evalAssume the list of symbols 3272 // whose assumptions have changed. For now we just iterate through the 3273 // bindings and check if any of the tracked symbols are NULL. This isn't 3274 // too bad since the number of symbols we will track in practice are 3275 // probably small and evalAssume is only called at branches and a few 3276 // other places. 3277 RefBindings B = state->get<RefBindings>(); 3278 3279 if (B.isEmpty()) 3280 return state; 3281 3282 bool changed = false; 3283 RefBindings::Factory &RefBFactory = state->get_context<RefBindings>(); 3284 3285 for (RefBindings::iterator I = B.begin(), E = B.end(); I != E; ++I) { 3286 // Check if the symbol is null (or equal to any constant). 3287 // If this is the case, stop tracking the symbol. 3288 if (state->getSymVal(I.getKey())) { 3289 changed = true; 3290 B = RefBFactory.remove(B, I.getKey()); 3291 } 3292 } 3293 3294 if (changed) 3295 state = state->set<RefBindings>(B); 3296 3297 return state; 3298} 3299 3300const ProgramState * 3301RetainCountChecker::checkRegionChanges(const ProgramState *state, 3302 const StoreManager::InvalidatedSymbols *invalidated, 3303 ArrayRef<const MemRegion *> ExplicitRegions, 3304 ArrayRef<const MemRegion *> Regions) const { 3305 if (!invalidated) 3306 return state; 3307 3308 llvm::SmallPtrSet<SymbolRef, 8> WhitelistedSymbols; 3309 for (ArrayRef<const MemRegion *>::iterator I = ExplicitRegions.begin(), 3310 E = ExplicitRegions.end(); I != E; ++I) { 3311 if (const SymbolicRegion *SR = (*I)->StripCasts()->getAs<SymbolicRegion>()) 3312 WhitelistedSymbols.insert(SR->getSymbol()); 3313 } 3314 3315 for (StoreManager::InvalidatedSymbols::const_iterator I=invalidated->begin(), 3316 E = invalidated->end(); I!=E; ++I) { 3317 SymbolRef sym = *I; 3318 if (WhitelistedSymbols.count(sym)) 3319 continue; 3320 // Remove any existing reference-count binding. 3321 state = state->remove<RefBindings>(sym); 3322 } 3323 return state; 3324} 3325 3326//===----------------------------------------------------------------------===// 3327// Handle dead symbols and end-of-path. 3328//===----------------------------------------------------------------------===// 3329 3330std::pair<ExplodedNode *, const ProgramState *> 3331RetainCountChecker::handleAutoreleaseCounts(const ProgramState *state, 3332 GenericNodeBuilderRefCount Bd, 3333 ExplodedNode *Pred, 3334 CheckerContext &Ctx, 3335 SymbolRef Sym, RefVal V) const { 3336 unsigned ACnt = V.getAutoreleaseCount(); 3337 3338 // No autorelease counts? Nothing to be done. 3339 if (!ACnt) 3340 return std::make_pair(Pred, state); 3341 3342 assert(!Ctx.isObjCGCEnabled() && "Autorelease counts in GC mode?"); 3343 unsigned Cnt = V.getCount(); 3344 3345 // FIXME: Handle sending 'autorelease' to already released object. 3346 3347 if (V.getKind() == RefVal::ReturnedOwned) 3348 ++Cnt; 3349 3350 if (ACnt <= Cnt) { 3351 if (ACnt == Cnt) { 3352 V.clearCounts(); 3353 if (V.getKind() == RefVal::ReturnedOwned) 3354 V = V ^ RefVal::ReturnedNotOwned; 3355 else 3356 V = V ^ RefVal::NotOwned; 3357 } else { 3358 V.setCount(Cnt - ACnt); 3359 V.setAutoreleaseCount(0); 3360 } 3361 state = state->set<RefBindings>(Sym, V); 3362 ExplodedNode *N = Bd.MakeNode(state, Pred); 3363 if (N == 0) 3364 state = 0; 3365 return std::make_pair(N, state); 3366 } 3367 3368 // Woah! More autorelease counts then retain counts left. 3369 // Emit hard error. 3370 V = V ^ RefVal::ErrorOverAutorelease; 3371 state = state->set<RefBindings>(Sym, V); 3372 3373 if (ExplodedNode *N = Bd.MakeNode(state, Pred, true)) { 3374 llvm::SmallString<128> sbuf; 3375 llvm::raw_svector_ostream os(sbuf); 3376 os << "Object over-autoreleased: object was sent -autorelease "; 3377 if (V.getAutoreleaseCount() > 1) 3378 os << V.getAutoreleaseCount() << " times "; 3379 os << "but the object has a +" << V.getCount() << " retain count"; 3380 3381 if (!overAutorelease) 3382 overAutorelease.reset(new OverAutorelease()); 3383 3384 const LangOptions &LOpts = Ctx.getASTContext().getLangOptions(); 3385 CFRefReport *report = 3386 new CFRefReport(*overAutorelease, LOpts, /* GCEnabled = */ false, 3387 SummaryLog, N, Sym, os.str()); 3388 Ctx.EmitReport(report); 3389 } 3390 3391 return std::make_pair((ExplodedNode *)0, (const ProgramState *)0); 3392} 3393 3394const ProgramState * 3395RetainCountChecker::handleSymbolDeath(const ProgramState *state, 3396 SymbolRef sid, RefVal V, 3397 SmallVectorImpl<SymbolRef> &Leaked) const { 3398 bool hasLeak = false; 3399 if (V.isOwned()) 3400 hasLeak = true; 3401 else if (V.isNotOwned() || V.isReturnedOwned()) 3402 hasLeak = (V.getCount() > 0); 3403 3404 if (!hasLeak) 3405 return state->remove<RefBindings>(sid); 3406 3407 Leaked.push_back(sid); 3408 return state->set<RefBindings>(sid, V ^ RefVal::ErrorLeak); 3409} 3410 3411ExplodedNode * 3412RetainCountChecker::processLeaks(const ProgramState *state, 3413 SmallVectorImpl<SymbolRef> &Leaked, 3414 GenericNodeBuilderRefCount &Builder, 3415 CheckerContext &Ctx, 3416 ExplodedNode *Pred) const { 3417 if (Leaked.empty()) 3418 return Pred; 3419 3420 // Generate an intermediate node representing the leak point. 3421 ExplodedNode *N = Builder.MakeNode(state, Pred); 3422 3423 if (N) { 3424 for (SmallVectorImpl<SymbolRef>::iterator 3425 I = Leaked.begin(), E = Leaked.end(); I != E; ++I) { 3426 3427 const LangOptions &LOpts = Ctx.getASTContext().getLangOptions(); 3428 bool GCEnabled = Ctx.isObjCGCEnabled(); 3429 CFRefBug *BT = Pred ? getLeakWithinFunctionBug(LOpts, GCEnabled) 3430 : getLeakAtReturnBug(LOpts, GCEnabled); 3431 assert(BT && "BugType not initialized."); 3432 3433 CFRefLeakReport *report = new CFRefLeakReport(*BT, LOpts, GCEnabled, 3434 SummaryLog, N, *I, Ctx); 3435 Ctx.EmitReport(report); 3436 } 3437 } 3438 3439 return N; 3440} 3441 3442void RetainCountChecker::checkEndPath(CheckerContext &Ctx) const { 3443 const ProgramState *state = Ctx.getState(); 3444 GenericNodeBuilderRefCount Bd(Ctx); 3445 RefBindings B = state->get<RefBindings>(); 3446 ExplodedNode *Pred = Ctx.getPredecessor(); 3447 3448 for (RefBindings::iterator I = B.begin(), E = B.end(); I != E; ++I) { 3449 llvm::tie(Pred, state) = handleAutoreleaseCounts(state, Bd, Pred, Ctx, 3450 I->first, I->second); 3451 if (!state) 3452 return; 3453 } 3454 3455 B = state->get<RefBindings>(); 3456 SmallVector<SymbolRef, 10> Leaked; 3457 3458 for (RefBindings::iterator I = B.begin(), E = B.end(); I != E; ++I) 3459 state = handleSymbolDeath(state, I->first, I->second, Leaked); 3460 3461 processLeaks(state, Leaked, Bd, Ctx, Pred); 3462} 3463 3464const ProgramPointTag * 3465RetainCountChecker::getDeadSymbolTag(SymbolRef sym) const { 3466 const SimpleProgramPointTag *&tag = DeadSymbolTags[sym]; 3467 if (!tag) { 3468 llvm::SmallString<64> buf; 3469 llvm::raw_svector_ostream out(buf); 3470 out << "RetainCountChecker : Dead Symbol : " << sym->getSymbolID(); 3471 tag = new SimpleProgramPointTag(out.str()); 3472 } 3473 return tag; 3474} 3475 3476void RetainCountChecker::checkDeadSymbols(SymbolReaper &SymReaper, 3477 CheckerContext &C) const { 3478 ExplodedNode *Pred = C.getPredecessor(); 3479 3480 const ProgramState *state = C.getState(); 3481 RefBindings B = state->get<RefBindings>(); 3482 3483 // Update counts from autorelease pools 3484 for (SymbolReaper::dead_iterator I = SymReaper.dead_begin(), 3485 E = SymReaper.dead_end(); I != E; ++I) { 3486 SymbolRef Sym = *I; 3487 if (const RefVal *T = B.lookup(Sym)){ 3488 // Use the symbol as the tag. 3489 // FIXME: This might not be as unique as we would like. 3490 GenericNodeBuilderRefCount Bd(C, getDeadSymbolTag(Sym)); 3491 llvm::tie(Pred, state) = handleAutoreleaseCounts(state, Bd, Pred, C, 3492 Sym, *T); 3493 if (!state) 3494 return; 3495 } 3496 } 3497 3498 B = state->get<RefBindings>(); 3499 SmallVector<SymbolRef, 10> Leaked; 3500 3501 for (SymbolReaper::dead_iterator I = SymReaper.dead_begin(), 3502 E = SymReaper.dead_end(); I != E; ++I) { 3503 if (const RefVal *T = B.lookup(*I)) 3504 state = handleSymbolDeath(state, *I, *T, Leaked); 3505 } 3506 3507 { 3508 GenericNodeBuilderRefCount Bd(C, this); 3509 Pred = processLeaks(state, Leaked, Bd, C, Pred); 3510 } 3511 3512 // Did we cache out? 3513 if (!Pred) 3514 return; 3515 3516 // Now generate a new node that nukes the old bindings. 3517 RefBindings::Factory &F = state->get_context<RefBindings>(); 3518 3519 for (SymbolReaper::dead_iterator I = SymReaper.dead_begin(), 3520 E = SymReaper.dead_end(); I != E; ++I) 3521 B = F.remove(B, *I); 3522 3523 state = state->set<RefBindings>(B); 3524 C.addTransition(state, Pred); 3525} 3526 3527//===----------------------------------------------------------------------===// 3528// Debug printing of refcount bindings and autorelease pools. 3529//===----------------------------------------------------------------------===// 3530 3531static void PrintPool(raw_ostream &Out, SymbolRef Sym, 3532 const ProgramState *State) { 3533 Out << ' '; 3534 if (Sym) 3535 Out << Sym->getSymbolID(); 3536 else 3537 Out << "<pool>"; 3538 Out << ":{"; 3539 3540 // Get the contents of the pool. 3541 if (const ARCounts *Cnts = State->get<AutoreleasePoolContents>(Sym)) 3542 for (ARCounts::iterator I = Cnts->begin(), E = Cnts->end(); I != E; ++I) 3543 Out << '(' << I.getKey() << ',' << I.getData() << ')'; 3544 3545 Out << '}'; 3546} 3547 3548static bool UsesAutorelease(const ProgramState *state) { 3549 // A state uses autorelease if it allocated an autorelease pool or if it has 3550 // objects in the caller's autorelease pool. 3551 return !state->get<AutoreleaseStack>().isEmpty() || 3552 state->get<AutoreleasePoolContents>(SymbolRef()); 3553} 3554 3555void RetainCountChecker::printState(raw_ostream &Out, const ProgramState *State, 3556 const char *NL, const char *Sep) const { 3557 3558 RefBindings B = State->get<RefBindings>(); 3559 3560 if (!B.isEmpty()) 3561 Out << Sep << NL; 3562 3563 for (RefBindings::iterator I = B.begin(), E = B.end(); I != E; ++I) { 3564 Out << I->first << " : "; 3565 I->second.print(Out); 3566 Out << NL; 3567 } 3568 3569 // Print the autorelease stack. 3570 if (UsesAutorelease(State)) { 3571 Out << Sep << NL << "AR pool stack:"; 3572 ARStack Stack = State->get<AutoreleaseStack>(); 3573 3574 PrintPool(Out, SymbolRef(), State); // Print the caller's pool. 3575 for (ARStack::iterator I = Stack.begin(), E = Stack.end(); I != E; ++I) 3576 PrintPool(Out, *I, State); 3577 3578 Out << NL; 3579 } 3580} 3581 3582//===----------------------------------------------------------------------===// 3583// Checker registration. 3584//===----------------------------------------------------------------------===// 3585 3586void ento::registerRetainCountChecker(CheckerManager &Mgr) { 3587 Mgr.registerChecker<RetainCountChecker>(); 3588} 3589 3590