RetainCountChecker.cpp revision 4eff823b8e015e003d05953c386d685ee6bb6235
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/StaticAnalyzer/Core/Checker.h" 22#include "clang/StaticAnalyzer/Core/CheckerManager.h" 23#include "clang/StaticAnalyzer/Core/BugReporter/BugType.h" 24#include "clang/StaticAnalyzer/Core/BugReporter/PathDiagnostic.h" 25#include "clang/StaticAnalyzer/Core/PathSensitive/CheckerContext.h" 26#include "clang/StaticAnalyzer/Core/PathSensitive/ExprEngineBuilders.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; 48 EndOfFunctionNodeBuilder *ENB; 49public: 50 GenericNodeBuilderRefCount(CheckerContext &c, 51 const ProgramPointTag *t) 52 : C(&c), tag(t), ENB(0) {} 53 54 GenericNodeBuilderRefCount(EndOfFunctionNodeBuilder &enb) 55 : C(0), tag(0), ENB(&enb) {} 56 57 ExplodedNode *MakeNode(const ProgramState *state, ExplodedNode *Pred) { 58 if (C) 59 return C->generateNode(state, Pred, tag, false); 60 61 assert(ENB); 62 return ENB->generateNode(state, Pred); 63 } 64}; 65} // end anonymous namespace 66 67//===----------------------------------------------------------------------===// 68// Primitives used for constructing summaries for function/method calls. 69//===----------------------------------------------------------------------===// 70 71/// ArgEffect is used to summarize a function/method call's effect on a 72/// particular argument. 73enum ArgEffect { DoNothing, Autorelease, Dealloc, DecRef, DecRefMsg, 74 DecRefBridgedTransfered, 75 IncRefMsg, IncRef, MakeCollectable, MayEscape, 76 NewAutoreleasePool, SelfOwn, StopTracking }; 77 78namespace llvm { 79template <> struct FoldingSetTrait<ArgEffect> { 80static inline void Profile(const ArgEffect X, FoldingSetNodeID& ID) { 81 ID.AddInteger((unsigned) X); 82} 83}; 84} // end llvm namespace 85 86/// ArgEffects summarizes the effects of a function/method call on all of 87/// its arguments. 88typedef llvm::ImmutableMap<unsigned,ArgEffect> ArgEffects; 89 90namespace { 91 92/// RetEffect is used to summarize a function/method call's behavior with 93/// respect to its return value. 94class RetEffect { 95public: 96 enum Kind { NoRet, OwnedSymbol, OwnedAllocatedSymbol, 97 NotOwnedSymbol, GCNotOwnedSymbol, ARCNotOwnedSymbol, 98 OwnedWhenTrackedReceiver }; 99 100 enum ObjKind { CF, ObjC, AnyObj }; 101 102private: 103 Kind K; 104 ObjKind O; 105 106 RetEffect(Kind k, ObjKind o = AnyObj) : K(k), O(o) {} 107 108public: 109 Kind getKind() const { return K; } 110 111 ObjKind getObjKind() const { return O; } 112 113 bool isOwned() const { 114 return K == OwnedSymbol || K == OwnedAllocatedSymbol || 115 K == OwnedWhenTrackedReceiver; 116 } 117 118 bool operator==(const RetEffect &Other) const { 119 return K == Other.K && O == Other.O; 120 } 121 122 static RetEffect MakeOwnedWhenTrackedReceiver() { 123 return RetEffect(OwnedWhenTrackedReceiver, ObjC); 124 } 125 126 static RetEffect MakeOwned(ObjKind o, bool isAllocated = false) { 127 return RetEffect(isAllocated ? OwnedAllocatedSymbol : OwnedSymbol, o); 128 } 129 static RetEffect MakeNotOwned(ObjKind o) { 130 return RetEffect(NotOwnedSymbol, o); 131 } 132 static RetEffect MakeGCNotOwned() { 133 return RetEffect(GCNotOwnedSymbol, ObjC); 134 } 135 static RetEffect MakeARCNotOwned() { 136 return RetEffect(ARCNotOwnedSymbol, ObjC); 137 } 138 static RetEffect MakeNoRet() { 139 return RetEffect(NoRet); 140 } 141}; 142 143//===----------------------------------------------------------------------===// 144// Reference-counting logic (typestate + counts). 145//===----------------------------------------------------------------------===// 146 147class RefVal { 148public: 149 enum Kind { 150 Owned = 0, // Owning reference. 151 NotOwned, // Reference is not owned by still valid (not freed). 152 Released, // Object has been released. 153 ReturnedOwned, // Returned object passes ownership to caller. 154 ReturnedNotOwned, // Return object does not pass ownership to caller. 155 ERROR_START, 156 ErrorDeallocNotOwned, // -dealloc called on non-owned object. 157 ErrorDeallocGC, // Calling -dealloc with GC enabled. 158 ErrorUseAfterRelease, // Object used after released. 159 ErrorReleaseNotOwned, // Release of an object that was not owned. 160 ERROR_LEAK_START, 161 ErrorLeak, // A memory leak due to excessive reference counts. 162 ErrorLeakReturned, // A memory leak due to the returning method not having 163 // the correct naming conventions. 164 ErrorGCLeakReturned, 165 ErrorOverAutorelease, 166 ErrorReturnedNotOwned 167 }; 168 169private: 170 Kind kind; 171 RetEffect::ObjKind okind; 172 unsigned Cnt; 173 unsigned ACnt; 174 QualType T; 175 176 RefVal(Kind k, RetEffect::ObjKind o, unsigned cnt, unsigned acnt, QualType t) 177 : kind(k), okind(o), Cnt(cnt), ACnt(acnt), T(t) {} 178 179public: 180 Kind getKind() const { return kind; } 181 182 RetEffect::ObjKind getObjKind() const { return okind; } 183 184 unsigned getCount() const { return Cnt; } 185 unsigned getAutoreleaseCount() const { return ACnt; } 186 unsigned getCombinedCounts() const { return Cnt + ACnt; } 187 void clearCounts() { Cnt = 0; ACnt = 0; } 188 void setCount(unsigned i) { Cnt = i; } 189 void setAutoreleaseCount(unsigned i) { ACnt = i; } 190 191 QualType getType() const { return T; } 192 193 bool isOwned() const { 194 return getKind() == Owned; 195 } 196 197 bool isNotOwned() const { 198 return getKind() == NotOwned; 199 } 200 201 bool isReturnedOwned() const { 202 return getKind() == ReturnedOwned; 203 } 204 205 bool isReturnedNotOwned() const { 206 return getKind() == ReturnedNotOwned; 207 } 208 209 static RefVal makeOwned(RetEffect::ObjKind o, QualType t, 210 unsigned Count = 1) { 211 return RefVal(Owned, o, Count, 0, t); 212 } 213 214 static RefVal makeNotOwned(RetEffect::ObjKind o, QualType t, 215 unsigned Count = 0) { 216 return RefVal(NotOwned, o, Count, 0, t); 217 } 218 219 // Comparison, profiling, and pretty-printing. 220 221 bool operator==(const RefVal& X) const { 222 return kind == X.kind && Cnt == X.Cnt && T == X.T && ACnt == X.ACnt; 223 } 224 225 RefVal operator-(size_t i) const { 226 return RefVal(getKind(), getObjKind(), getCount() - i, 227 getAutoreleaseCount(), getType()); 228 } 229 230 RefVal operator+(size_t i) const { 231 return RefVal(getKind(), getObjKind(), getCount() + i, 232 getAutoreleaseCount(), getType()); 233 } 234 235 RefVal operator^(Kind k) const { 236 return RefVal(k, getObjKind(), getCount(), getAutoreleaseCount(), 237 getType()); 238 } 239 240 RefVal autorelease() const { 241 return RefVal(getKind(), getObjKind(), getCount(), getAutoreleaseCount()+1, 242 getType()); 243 } 244 245 void Profile(llvm::FoldingSetNodeID& ID) const { 246 ID.AddInteger((unsigned) kind); 247 ID.AddInteger(Cnt); 248 ID.AddInteger(ACnt); 249 ID.Add(T); 250 } 251 252 void print(raw_ostream &Out) const; 253}; 254 255void RefVal::print(raw_ostream &Out) const { 256 if (!T.isNull()) 257 Out << "Tracked " << T.getAsString() << '/'; 258 259 switch (getKind()) { 260 default: llvm_unreachable("Invalid RefVal kind"); 261 case Owned: { 262 Out << "Owned"; 263 unsigned cnt = getCount(); 264 if (cnt) Out << " (+ " << cnt << ")"; 265 break; 266 } 267 268 case NotOwned: { 269 Out << "NotOwned"; 270 unsigned cnt = getCount(); 271 if (cnt) Out << " (+ " << cnt << ")"; 272 break; 273 } 274 275 case ReturnedOwned: { 276 Out << "ReturnedOwned"; 277 unsigned cnt = getCount(); 278 if (cnt) Out << " (+ " << cnt << ")"; 279 break; 280 } 281 282 case ReturnedNotOwned: { 283 Out << "ReturnedNotOwned"; 284 unsigned cnt = getCount(); 285 if (cnt) Out << " (+ " << cnt << ")"; 286 break; 287 } 288 289 case Released: 290 Out << "Released"; 291 break; 292 293 case ErrorDeallocGC: 294 Out << "-dealloc (GC)"; 295 break; 296 297 case ErrorDeallocNotOwned: 298 Out << "-dealloc (not-owned)"; 299 break; 300 301 case ErrorLeak: 302 Out << "Leaked"; 303 break; 304 305 case ErrorLeakReturned: 306 Out << "Leaked (Bad naming)"; 307 break; 308 309 case ErrorGCLeakReturned: 310 Out << "Leaked (GC-ed at return)"; 311 break; 312 313 case ErrorUseAfterRelease: 314 Out << "Use-After-Release [ERROR]"; 315 break; 316 317 case ErrorReleaseNotOwned: 318 Out << "Release of Not-Owned [ERROR]"; 319 break; 320 321 case RefVal::ErrorOverAutorelease: 322 Out << "Over autoreleased"; 323 break; 324 325 case RefVal::ErrorReturnedNotOwned: 326 Out << "Non-owned object returned instead of owned"; 327 break; 328 } 329 330 if (ACnt) { 331 Out << " [ARC +" << ACnt << ']'; 332 } 333} 334} //end anonymous namespace 335 336//===----------------------------------------------------------------------===// 337// RefBindings - State used to track object reference counts. 338//===----------------------------------------------------------------------===// 339 340typedef llvm::ImmutableMap<SymbolRef, RefVal> RefBindings; 341 342namespace clang { 343namespace ento { 344template<> 345struct ProgramStateTrait<RefBindings> 346 : public ProgramStatePartialTrait<RefBindings> { 347 static void *GDMIndex() { 348 static int RefBIndex = 0; 349 return &RefBIndex; 350 } 351}; 352} 353} 354 355//===----------------------------------------------------------------------===// 356// Function/Method behavior summaries. 357//===----------------------------------------------------------------------===// 358 359namespace { 360class RetainSummary { 361 /// Args - an ordered vector of (index, ArgEffect) pairs, where index 362 /// specifies the argument (starting from 0). This can be sparsely 363 /// populated; arguments with no entry in Args use 'DefaultArgEffect'. 364 ArgEffects Args; 365 366 /// DefaultArgEffect - The default ArgEffect to apply to arguments that 367 /// do not have an entry in Args. 368 ArgEffect DefaultArgEffect; 369 370 /// Receiver - If this summary applies to an Objective-C message expression, 371 /// this is the effect applied to the state of the receiver. 372 ArgEffect Receiver; 373 374 /// Ret - The effect on the return value. Used to indicate if the 375 /// function/method call returns a new tracked symbol. 376 RetEffect Ret; 377 378public: 379 RetainSummary(ArgEffects A, RetEffect R, ArgEffect defaultEff, 380 ArgEffect ReceiverEff) 381 : Args(A), DefaultArgEffect(defaultEff), Receiver(ReceiverEff), Ret(R) {} 382 383 /// getArg - Return the argument effect on the argument specified by 384 /// idx (starting from 0). 385 ArgEffect getArg(unsigned idx) const { 386 if (const ArgEffect *AE = Args.lookup(idx)) 387 return *AE; 388 389 return DefaultArgEffect; 390 } 391 392 void addArg(ArgEffects::Factory &af, unsigned idx, ArgEffect e) { 393 Args = af.add(Args, idx, e); 394 } 395 396 /// setDefaultArgEffect - Set the default argument effect. 397 void setDefaultArgEffect(ArgEffect E) { 398 DefaultArgEffect = E; 399 } 400 401 /// getRetEffect - Returns the effect on the return value of the call. 402 RetEffect getRetEffect() const { return Ret; } 403 404 /// setRetEffect - Set the effect of the return value of the call. 405 void setRetEffect(RetEffect E) { Ret = E; } 406 407 408 /// Sets the effect on the receiver of the message. 409 void setReceiverEffect(ArgEffect e) { Receiver = e; } 410 411 /// getReceiverEffect - Returns the effect on the receiver of the call. 412 /// This is only meaningful if the summary applies to an ObjCMessageExpr*. 413 ArgEffect getReceiverEffect() const { return Receiver; } 414 415 /// Test if two retain summaries are identical. Note that merely equivalent 416 /// summaries are not necessarily identical (for example, if an explicit 417 /// argument effect matches the default effect). 418 bool operator==(const RetainSummary &Other) const { 419 return Args == Other.Args && DefaultArgEffect == Other.DefaultArgEffect && 420 Receiver == Other.Receiver && Ret == Other.Ret; 421 } 422}; 423} // end anonymous namespace 424 425//===----------------------------------------------------------------------===// 426// Data structures for constructing summaries. 427//===----------------------------------------------------------------------===// 428 429namespace { 430class ObjCSummaryKey { 431 IdentifierInfo* II; 432 Selector S; 433public: 434 ObjCSummaryKey(IdentifierInfo* ii, Selector s) 435 : II(ii), S(s) {} 436 437 ObjCSummaryKey(const ObjCInterfaceDecl *d, Selector s) 438 : II(d ? d->getIdentifier() : 0), S(s) {} 439 440 ObjCSummaryKey(const ObjCInterfaceDecl *d, IdentifierInfo *ii, Selector s) 441 : II(d ? d->getIdentifier() : ii), S(s) {} 442 443 ObjCSummaryKey(Selector s) 444 : II(0), S(s) {} 445 446 IdentifierInfo* getIdentifier() const { return II; } 447 Selector getSelector() const { return S; } 448}; 449} 450 451namespace llvm { 452template <> struct DenseMapInfo<ObjCSummaryKey> { 453 static inline ObjCSummaryKey getEmptyKey() { 454 return ObjCSummaryKey(DenseMapInfo<IdentifierInfo*>::getEmptyKey(), 455 DenseMapInfo<Selector>::getEmptyKey()); 456 } 457 458 static inline ObjCSummaryKey getTombstoneKey() { 459 return ObjCSummaryKey(DenseMapInfo<IdentifierInfo*>::getTombstoneKey(), 460 DenseMapInfo<Selector>::getTombstoneKey()); 461 } 462 463 static unsigned getHashValue(const ObjCSummaryKey &V) { 464 return (DenseMapInfo<IdentifierInfo*>::getHashValue(V.getIdentifier()) 465 & 0x88888888) 466 | (DenseMapInfo<Selector>::getHashValue(V.getSelector()) 467 & 0x55555555); 468 } 469 470 static bool isEqual(const ObjCSummaryKey& LHS, const ObjCSummaryKey& RHS) { 471 return DenseMapInfo<IdentifierInfo*>::isEqual(LHS.getIdentifier(), 472 RHS.getIdentifier()) && 473 DenseMapInfo<Selector>::isEqual(LHS.getSelector(), 474 RHS.getSelector()); 475 } 476 477}; 478template <> 479struct isPodLike<ObjCSummaryKey> { static const bool value = true; }; 480} // end llvm namespace 481 482namespace { 483class ObjCSummaryCache { 484 typedef llvm::DenseMap<ObjCSummaryKey, RetainSummary*> MapTy; 485 MapTy M; 486public: 487 ObjCSummaryCache() {} 488 489 RetainSummary* find(const ObjCInterfaceDecl *D, IdentifierInfo *ClsName, 490 Selector S) { 491 // Lookup the method using the decl for the class @interface. If we 492 // have no decl, lookup using the class name. 493 return D ? find(D, S) : find(ClsName, S); 494 } 495 496 RetainSummary* find(const ObjCInterfaceDecl *D, Selector S) { 497 // Do a lookup with the (D,S) pair. If we find a match return 498 // the iterator. 499 ObjCSummaryKey K(D, S); 500 MapTy::iterator I = M.find(K); 501 502 if (I != M.end() || !D) 503 return I->second; 504 505 // Walk the super chain. If we find a hit with a parent, we'll end 506 // up returning that summary. We actually allow that key (null,S), as 507 // we cache summaries for the null ObjCInterfaceDecl* to allow us to 508 // generate initial summaries without having to worry about NSObject 509 // being declared. 510 // FIXME: We may change this at some point. 511 for (ObjCInterfaceDecl *C=D->getSuperClass() ;; C=C->getSuperClass()) { 512 if ((I = M.find(ObjCSummaryKey(C, S))) != M.end()) 513 break; 514 515 if (!C) 516 return NULL; 517 } 518 519 // Cache the summary with original key to make the next lookup faster 520 // and return the iterator. 521 RetainSummary *Summ = I->second; 522 M[K] = Summ; 523 return Summ; 524 } 525 526 RetainSummary* find(IdentifierInfo* II, Selector S) { 527 // FIXME: Class method lookup. Right now we dont' have a good way 528 // of going between IdentifierInfo* and the class hierarchy. 529 MapTy::iterator I = M.find(ObjCSummaryKey(II, S)); 530 531 if (I == M.end()) 532 I = M.find(ObjCSummaryKey(S)); 533 534 return I == M.end() ? NULL : I->second; 535 } 536 537 RetainSummary*& operator[](ObjCSummaryKey K) { 538 return M[K]; 539 } 540 541 RetainSummary*& operator[](Selector S) { 542 return M[ ObjCSummaryKey(S) ]; 543 } 544}; 545} // end anonymous namespace 546 547//===----------------------------------------------------------------------===// 548// Data structures for managing collections of summaries. 549//===----------------------------------------------------------------------===// 550 551namespace { 552class RetainSummaryManager { 553 554 //==-----------------------------------------------------------------==// 555 // Typedefs. 556 //==-----------------------------------------------------------------==// 557 558 typedef llvm::DenseMap<const FunctionDecl*, RetainSummary*> 559 FuncSummariesTy; 560 561 typedef ObjCSummaryCache ObjCMethodSummariesTy; 562 563 //==-----------------------------------------------------------------==// 564 // Data. 565 //==-----------------------------------------------------------------==// 566 567 /// Ctx - The ASTContext object for the analyzed ASTs. 568 ASTContext &Ctx; 569 570 /// GCEnabled - Records whether or not the analyzed code runs in GC mode. 571 const bool GCEnabled; 572 573 /// Records whether or not the analyzed code runs in ARC mode. 574 const bool ARCEnabled; 575 576 /// FuncSummaries - A map from FunctionDecls to summaries. 577 FuncSummariesTy FuncSummaries; 578 579 /// ObjCClassMethodSummaries - A map from selectors (for instance methods) 580 /// to summaries. 581 ObjCMethodSummariesTy ObjCClassMethodSummaries; 582 583 /// ObjCMethodSummaries - A map from selectors to summaries. 584 ObjCMethodSummariesTy ObjCMethodSummaries; 585 586 /// BPAlloc - A BumpPtrAllocator used for allocating summaries, ArgEffects, 587 /// and all other data used by the checker. 588 llvm::BumpPtrAllocator BPAlloc; 589 590 /// AF - A factory for ArgEffects objects. 591 ArgEffects::Factory AF; 592 593 /// ScratchArgs - A holding buffer for construct ArgEffects. 594 ArgEffects ScratchArgs; 595 596 /// ObjCAllocRetE - Default return effect for methods returning Objective-C 597 /// objects. 598 RetEffect ObjCAllocRetE; 599 600 /// ObjCInitRetE - Default return effect for init methods returning 601 /// Objective-C objects. 602 RetEffect ObjCInitRetE; 603 604 RetainSummary DefaultSummary; 605 RetainSummary* StopSummary; 606 607 //==-----------------------------------------------------------------==// 608 // Methods. 609 //==-----------------------------------------------------------------==// 610 611 /// getArgEffects - Returns a persistent ArgEffects object based on the 612 /// data in ScratchArgs. 613 ArgEffects getArgEffects(); 614 615 enum UnaryFuncKind { cfretain, cfrelease, cfmakecollectable }; 616 617public: 618 RetEffect getObjAllocRetEffect() const { return ObjCAllocRetE; } 619 620 RetainSummary* getUnarySummary(const FunctionType* FT, UnaryFuncKind func); 621 622 RetainSummary* getCFSummaryCreateRule(const FunctionDecl *FD); 623 RetainSummary* getCFSummaryGetRule(const FunctionDecl *FD); 624 RetainSummary* getCFCreateGetRuleSummary(const FunctionDecl *FD); 625 626 RetainSummary* getPersistentSummary(ArgEffects AE, RetEffect RetEff, 627 ArgEffect ReceiverEff = DoNothing, 628 ArgEffect DefaultEff = MayEscape); 629 630 RetainSummary* getPersistentSummary(RetEffect RE, 631 ArgEffect ReceiverEff = DoNothing, 632 ArgEffect DefaultEff = MayEscape) { 633 return getPersistentSummary(getArgEffects(), RE, ReceiverEff, DefaultEff); 634 } 635 636 RetainSummary *getPersistentStopSummary() { 637 if (StopSummary) 638 return StopSummary; 639 640 StopSummary = getPersistentSummary(RetEffect::MakeNoRet(), 641 StopTracking, StopTracking); 642 643 return StopSummary; 644 } 645 646 RetainSummary *getInitMethodSummary(QualType RetTy); 647 648 void InitializeClassMethodSummaries(); 649 void InitializeMethodSummaries(); 650private: 651 void addNSObjectClsMethSummary(Selector S, RetainSummary *Summ) { 652 ObjCClassMethodSummaries[S] = Summ; 653 } 654 655 void addNSObjectMethSummary(Selector S, RetainSummary *Summ) { 656 ObjCMethodSummaries[S] = Summ; 657 } 658 659 void addClassMethSummary(const char* Cls, const char* nullaryName, 660 RetainSummary *Summ) { 661 IdentifierInfo* ClsII = &Ctx.Idents.get(Cls); 662 Selector S = GetNullarySelector(nullaryName, Ctx); 663 ObjCClassMethodSummaries[ObjCSummaryKey(ClsII, S)] = Summ; 664 } 665 666 void addInstMethSummary(const char* Cls, const char* nullaryName, 667 RetainSummary *Summ) { 668 IdentifierInfo* ClsII = &Ctx.Idents.get(Cls); 669 Selector S = GetNullarySelector(nullaryName, Ctx); 670 ObjCMethodSummaries[ObjCSummaryKey(ClsII, S)] = Summ; 671 } 672 673 Selector generateSelector(va_list argp) { 674 SmallVector<IdentifierInfo*, 10> II; 675 676 while (const char* s = va_arg(argp, const char*)) 677 II.push_back(&Ctx.Idents.get(s)); 678 679 return Ctx.Selectors.getSelector(II.size(), &II[0]); 680 } 681 682 void addMethodSummary(IdentifierInfo *ClsII, ObjCMethodSummariesTy& Summaries, 683 RetainSummary* Summ, va_list argp) { 684 Selector S = generateSelector(argp); 685 Summaries[ObjCSummaryKey(ClsII, S)] = Summ; 686 } 687 688 void addInstMethSummary(const char* Cls, RetainSummary* Summ, ...) { 689 va_list argp; 690 va_start(argp, Summ); 691 addMethodSummary(&Ctx.Idents.get(Cls), ObjCMethodSummaries, Summ, argp); 692 va_end(argp); 693 } 694 695 void addClsMethSummary(const char* Cls, RetainSummary* Summ, ...) { 696 va_list argp; 697 va_start(argp, Summ); 698 addMethodSummary(&Ctx.Idents.get(Cls),ObjCClassMethodSummaries, Summ, argp); 699 va_end(argp); 700 } 701 702 void addClsMethSummary(IdentifierInfo *II, RetainSummary* Summ, ...) { 703 va_list argp; 704 va_start(argp, Summ); 705 addMethodSummary(II, ObjCClassMethodSummaries, Summ, argp); 706 va_end(argp); 707 } 708 709public: 710 711 RetainSummaryManager(ASTContext &ctx, bool gcenabled, bool usesARC) 712 : Ctx(ctx), 713 GCEnabled(gcenabled), 714 ARCEnabled(usesARC), 715 AF(BPAlloc), ScratchArgs(AF.getEmptyMap()), 716 ObjCAllocRetE(gcenabled 717 ? RetEffect::MakeGCNotOwned() 718 : (usesARC ? RetEffect::MakeARCNotOwned() 719 : RetEffect::MakeOwned(RetEffect::ObjC, true))), 720 ObjCInitRetE(gcenabled 721 ? RetEffect::MakeGCNotOwned() 722 : (usesARC ? RetEffect::MakeARCNotOwned() 723 : RetEffect::MakeOwnedWhenTrackedReceiver())), 724 DefaultSummary(AF.getEmptyMap() /* per-argument effects (none) */, 725 RetEffect::MakeNoRet() /* return effect */, 726 MayEscape, /* default argument effect */ 727 DoNothing /* receiver effect */), 728 StopSummary(0) { 729 730 InitializeClassMethodSummaries(); 731 InitializeMethodSummaries(); 732 } 733 734 RetainSummary* getSummary(const FunctionDecl *FD); 735 736 RetainSummary *getInstanceMethodSummary(const ObjCMessage &msg, 737 const ProgramState *state, 738 const LocationContext *LC); 739 740 RetainSummary* getInstanceMethodSummary(const ObjCMessage &msg, 741 const ObjCInterfaceDecl *ID) { 742 return getInstanceMethodSummary(msg.getSelector(), 0, 743 ID, msg.getMethodDecl(), msg.getType(Ctx)); 744 } 745 746 RetainSummary* getInstanceMethodSummary(Selector S, IdentifierInfo *ClsName, 747 const ObjCInterfaceDecl *ID, 748 const ObjCMethodDecl *MD, 749 QualType RetTy); 750 751 RetainSummary *getClassMethodSummary(Selector S, IdentifierInfo *ClsName, 752 const ObjCInterfaceDecl *ID, 753 const ObjCMethodDecl *MD, 754 QualType RetTy); 755 756 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 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 RetainSummary* getCommonMethodSummary(const ObjCMethodDecl *MD, 783 Selector S, QualType RetTy); 784 785 void updateSummaryFromAnnotations(RetainSummary *&Summ, 786 const ObjCMethodDecl *MD); 787 788 void updateSummaryFromAnnotations(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 RetainSummary *copySummary(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 RetainSummary *&RealSummary; 811 RetainSummary ScratchSummary; 812 bool Accessed; 813public: 814 RetainSummaryTemplate(RetainSummary *&real, const RetainSummary &base, 815 RetainSummaryManager &manager) 816 : Manager(manager), RealSummary(real), ScratchSummary(base), Accessed(false) 817 {} 818 819 ~RetainSummaryTemplate() { 820 if (!RealSummary && Accessed) 821 RealSummary = Manager.copySummary(&ScratchSummary); 822 } 823 824 RetainSummary &operator*() { 825 Accessed = true; 826 return RealSummary ? *RealSummary : ScratchSummary; 827 } 828 829 RetainSummary *operator->() { 830 Accessed = true; 831 return RealSummary ? RealSummary : &ScratchSummary; 832 } 833}; 834 835} // end anonymous namespace 836 837//===----------------------------------------------------------------------===// 838// Implementation of checker data structures. 839//===----------------------------------------------------------------------===// 840 841ArgEffects RetainSummaryManager::getArgEffects() { 842 ArgEffects AE = ScratchArgs; 843 ScratchArgs = AF.getEmptyMap(); 844 return AE; 845} 846 847RetainSummary* 848RetainSummaryManager::getPersistentSummary(ArgEffects AE, RetEffect RetEff, 849 ArgEffect ReceiverEff, 850 ArgEffect DefaultEff) { 851 // Create the summary and return it. 852 RetainSummary *Summ = (RetainSummary*) BPAlloc.Allocate<RetainSummary>(); 853 new (Summ) RetainSummary(AE, RetEff, DefaultEff, ReceiverEff); 854 return Summ; 855} 856 857//===----------------------------------------------------------------------===// 858// Summary creation for functions (largely uses of Core Foundation). 859//===----------------------------------------------------------------------===// 860 861static bool isRetain(const FunctionDecl *FD, StringRef FName) { 862 return FName.endswith("Retain"); 863} 864 865static bool isRelease(const FunctionDecl *FD, StringRef FName) { 866 return FName.endswith("Release"); 867} 868 869static bool isMakeCollectable(const FunctionDecl *FD, StringRef FName) { 870 // FIXME: Remove FunctionDecl parameter. 871 // FIXME: Is it really okay if MakeCollectable isn't a suffix? 872 return FName.find("MakeCollectable") != StringRef::npos; 873} 874 875RetainSummary* RetainSummaryManager::getSummary(const FunctionDecl *FD) { 876 // Look up a summary in our cache of FunctionDecls -> Summaries. 877 FuncSummariesTy::iterator I = FuncSummaries.find(FD); 878 if (I != FuncSummaries.end()) 879 return I->second; 880 881 // No summary? Generate one. 882 RetainSummary *S = 0; 883 884 do { 885 // We generate "stop" summaries for implicitly defined functions. 886 if (FD->isImplicit()) { 887 S = getPersistentStopSummary(); 888 break; 889 } 890 // For C++ methods, generate an implicit "stop" summary as well. We 891 // can relax this once we have a clear policy for C++ methods and 892 // ownership attributes. 893 if (isa<CXXMethodDecl>(FD)) { 894 S = getPersistentStopSummary(); 895 break; 896 } 897 898 // [PR 3337] Use 'getAs<FunctionType>' to strip away any typedefs on the 899 // function's type. 900 const FunctionType* FT = FD->getType()->getAs<FunctionType>(); 901 const IdentifierInfo *II = FD->getIdentifier(); 902 if (!II) 903 break; 904 905 StringRef FName = II->getName(); 906 907 // Strip away preceding '_'. Doing this here will effect all the checks 908 // down below. 909 FName = FName.substr(FName.find_first_not_of('_')); 910 911 // Inspect the result type. 912 QualType RetTy = FT->getResultType(); 913 914 // FIXME: This should all be refactored into a chain of "summary lookup" 915 // filters. 916 assert(ScratchArgs.isEmpty()); 917 918 if (FName == "pthread_create") { 919 // Part of: <rdar://problem/7299394>. This will be addressed 920 // better with IPA. 921 S = getPersistentStopSummary(); 922 } else if (FName == "NSMakeCollectable") { 923 // Handle: id NSMakeCollectable(CFTypeRef) 924 S = (RetTy->isObjCIdType()) 925 ? getUnarySummary(FT, cfmakecollectable) 926 : getPersistentStopSummary(); 927 } else if (FName == "IOBSDNameMatching" || 928 FName == "IOServiceMatching" || 929 FName == "IOServiceNameMatching" || 930 FName == "IORegistryEntryIDMatching" || 931 FName == "IOOpenFirmwarePathMatching") { 932 // Part of <rdar://problem/6961230>. (IOKit) 933 // This should be addressed using a API table. 934 S = getPersistentSummary(RetEffect::MakeOwned(RetEffect::CF, true), 935 DoNothing, DoNothing); 936 } else if (FName == "IOServiceGetMatchingService" || 937 FName == "IOServiceGetMatchingServices") { 938 // FIXES: <rdar://problem/6326900> 939 // This should be addressed using a API table. This strcmp is also 940 // a little gross, but there is no need to super optimize here. 941 ScratchArgs = AF.add(ScratchArgs, 1, DecRef); 942 S = getPersistentSummary(RetEffect::MakeNoRet(), DoNothing, DoNothing); 943 } else if (FName == "IOServiceAddNotification" || 944 FName == "IOServiceAddMatchingNotification") { 945 // Part of <rdar://problem/6961230>. (IOKit) 946 // This should be addressed using a API table. 947 ScratchArgs = AF.add(ScratchArgs, 2, DecRef); 948 S = getPersistentSummary(RetEffect::MakeNoRet(), DoNothing, DoNothing); 949 } else if (FName == "CVPixelBufferCreateWithBytes") { 950 // FIXES: <rdar://problem/7283567> 951 // Eventually this can be improved by recognizing that the pixel 952 // buffer passed to CVPixelBufferCreateWithBytes is released via 953 // a callback and doing full IPA to make sure this is done correctly. 954 // FIXME: This function has an out parameter that returns an 955 // allocated object. 956 ScratchArgs = AF.add(ScratchArgs, 7, StopTracking); 957 S = getPersistentSummary(RetEffect::MakeNoRet(), DoNothing, DoNothing); 958 } else if (FName == "CGBitmapContextCreateWithData") { 959 // FIXES: <rdar://problem/7358899> 960 // Eventually this can be improved by recognizing that 'releaseInfo' 961 // passed to CGBitmapContextCreateWithData is released via 962 // a callback and doing full IPA to make sure this is done correctly. 963 ScratchArgs = AF.add(ScratchArgs, 8, StopTracking); 964 S = getPersistentSummary(RetEffect::MakeOwned(RetEffect::CF, true), 965 DoNothing, DoNothing); 966 } else if (FName == "CVPixelBufferCreateWithPlanarBytes") { 967 // FIXES: <rdar://problem/7283567> 968 // Eventually this can be improved by recognizing that the pixel 969 // buffer passed to CVPixelBufferCreateWithPlanarBytes is released 970 // via a callback and doing full IPA to make sure this is done 971 // correctly. 972 ScratchArgs = AF.add(ScratchArgs, 12, StopTracking); 973 S = getPersistentSummary(RetEffect::MakeNoRet(), DoNothing, DoNothing); 974 } 975 976 // Did we get a summary? 977 if (S) 978 break; 979 980 // Enable this code once the semantics of NSDeallocateObject are resolved 981 // for GC. <rdar://problem/6619988> 982#if 0 983 // Handle: NSDeallocateObject(id anObject); 984 // This method does allow 'nil' (although we don't check it now). 985 if (strcmp(FName, "NSDeallocateObject") == 0) { 986 return RetTy == Ctx.VoidTy 987 ? getPersistentSummary(RetEffect::MakeNoRet(), DoNothing, Dealloc) 988 : getPersistentStopSummary(); 989 } 990#endif 991 992 if (RetTy->isPointerType()) { 993 // For CoreFoundation ('CF') types. 994 if (cocoa::isRefType(RetTy, "CF", FName)) { 995 if (isRetain(FD, FName)) 996 S = getUnarySummary(FT, cfretain); 997 else if (isMakeCollectable(FD, FName)) 998 S = getUnarySummary(FT, cfmakecollectable); 999 else 1000 S = getCFCreateGetRuleSummary(FD); 1001 1002 break; 1003 } 1004 1005 // For CoreGraphics ('CG') types. 1006 if (cocoa::isRefType(RetTy, "CG", FName)) { 1007 if (isRetain(FD, FName)) 1008 S = getUnarySummary(FT, cfretain); 1009 else 1010 S = getCFCreateGetRuleSummary(FD); 1011 1012 break; 1013 } 1014 1015 // For the Disk Arbitration API (DiskArbitration/DADisk.h) 1016 if (cocoa::isRefType(RetTy, "DADisk") || 1017 cocoa::isRefType(RetTy, "DADissenter") || 1018 cocoa::isRefType(RetTy, "DASessionRef")) { 1019 S = getCFCreateGetRuleSummary(FD); 1020 break; 1021 } 1022 1023 break; 1024 } 1025 1026 // Check for release functions, the only kind of functions that we care 1027 // about that don't return a pointer type. 1028 if (FName[0] == 'C' && (FName[1] == 'F' || FName[1] == 'G')) { 1029 // Test for 'CGCF'. 1030 FName = FName.substr(FName.startswith("CGCF") ? 4 : 2); 1031 1032 if (isRelease(FD, FName)) 1033 S = getUnarySummary(FT, cfrelease); 1034 else { 1035 assert (ScratchArgs.isEmpty()); 1036 // Remaining CoreFoundation and CoreGraphics functions. 1037 // We use to assume that they all strictly followed the ownership idiom 1038 // and that ownership cannot be transferred. While this is technically 1039 // correct, many methods allow a tracked object to escape. For example: 1040 // 1041 // CFMutableDictionaryRef x = CFDictionaryCreateMutable(...); 1042 // CFDictionaryAddValue(y, key, x); 1043 // CFRelease(x); 1044 // ... it is okay to use 'x' since 'y' has a reference to it 1045 // 1046 // We handle this and similar cases with the follow heuristic. If the 1047 // function name contains "InsertValue", "SetValue", "AddValue", 1048 // "AppendValue", or "SetAttribute", then we assume that arguments may 1049 // "escape." This means that something else holds on to the object, 1050 // allowing it be used even after its local retain count drops to 0. 1051 ArgEffect E = (StrInStrNoCase(FName, "InsertValue") != StringRef::npos|| 1052 StrInStrNoCase(FName, "AddValue") != StringRef::npos || 1053 StrInStrNoCase(FName, "SetValue") != StringRef::npos || 1054 StrInStrNoCase(FName, "AppendValue") != StringRef::npos|| 1055 StrInStrNoCase(FName, "SetAttribute") != StringRef::npos) 1056 ? MayEscape : DoNothing; 1057 1058 S = getPersistentSummary(RetEffect::MakeNoRet(), DoNothing, E); 1059 } 1060 } 1061 } 1062 while (0); 1063 1064 // Annotations override defaults. 1065 updateSummaryFromAnnotations(S, FD); 1066 1067 FuncSummaries[FD] = S; 1068 return S; 1069} 1070 1071RetainSummary* 1072RetainSummaryManager::getCFCreateGetRuleSummary(const FunctionDecl *FD) { 1073 if (coreFoundation::followsCreateRule(FD)) 1074 return getCFSummaryCreateRule(FD); 1075 1076 return getCFSummaryGetRule(FD); 1077} 1078 1079RetainSummary* 1080RetainSummaryManager::getUnarySummary(const FunctionType* FT, 1081 UnaryFuncKind func) { 1082 1083 // Sanity check that this is *really* a unary function. This can 1084 // happen if people do weird things. 1085 const FunctionProtoType* FTP = dyn_cast<FunctionProtoType>(FT); 1086 if (!FTP || FTP->getNumArgs() != 1) 1087 return getPersistentStopSummary(); 1088 1089 assert (ScratchArgs.isEmpty()); 1090 1091 ArgEffect Effect; 1092 switch (func) { 1093 case cfretain: Effect = IncRef; break; 1094 case cfrelease: Effect = DecRef; break; 1095 case cfmakecollectable: Effect = MakeCollectable; break; 1096 default: llvm_unreachable("Not a supported unary function."); 1097 } 1098 1099 ScratchArgs = AF.add(ScratchArgs, 0, Effect); 1100 return getPersistentSummary(RetEffect::MakeNoRet(), DoNothing, DoNothing); 1101} 1102 1103RetainSummary* 1104RetainSummaryManager::getCFSummaryCreateRule(const FunctionDecl *FD) { 1105 assert (ScratchArgs.isEmpty()); 1106 1107 return getPersistentSummary(RetEffect::MakeOwned(RetEffect::CF, true)); 1108} 1109 1110RetainSummary* 1111RetainSummaryManager::getCFSummaryGetRule(const FunctionDecl *FD) { 1112 assert (ScratchArgs.isEmpty()); 1113 return getPersistentSummary(RetEffect::MakeNotOwned(RetEffect::CF), 1114 DoNothing, DoNothing); 1115} 1116 1117//===----------------------------------------------------------------------===// 1118// Summary creation for Selectors. 1119//===----------------------------------------------------------------------===// 1120 1121RetainSummary* 1122RetainSummaryManager::getInitMethodSummary(QualType RetTy) { 1123 assert(ScratchArgs.isEmpty()); 1124 // 'init' methods conceptually return a newly allocated object and claim 1125 // the receiver. 1126 if (cocoa::isCocoaObjectRef(RetTy) || 1127 coreFoundation::isCFObjectRef(RetTy)) 1128 return getPersistentSummary(ObjCInitRetE, DecRefMsg); 1129 1130 return 0; 1131} 1132 1133void 1134RetainSummaryManager::updateSummaryFromAnnotations(RetainSummary *&Summ, 1135 const FunctionDecl *FD) { 1136 if (!FD) 1137 return; 1138 1139 RetainSummaryTemplate Template(Summ, DefaultSummary, *this); 1140 1141 // Effects on the parameters. 1142 unsigned parm_idx = 0; 1143 for (FunctionDecl::param_const_iterator pi = FD->param_begin(), 1144 pe = FD->param_end(); pi != pe; ++pi, ++parm_idx) { 1145 const ParmVarDecl *pd = *pi; 1146 if (pd->getAttr<NSConsumedAttr>()) { 1147 if (!GCEnabled) { 1148 Template->addArg(AF, parm_idx, DecRef); 1149 } 1150 } else if (pd->getAttr<CFConsumedAttr>()) { 1151 Template->addArg(AF, parm_idx, DecRef); 1152 } 1153 } 1154 1155 QualType RetTy = FD->getResultType(); 1156 1157 // Determine if there is a special return effect for this method. 1158 if (cocoa::isCocoaObjectRef(RetTy)) { 1159 if (FD->getAttr<NSReturnsRetainedAttr>()) { 1160 Template->setRetEffect(ObjCAllocRetE); 1161 } 1162 else if (FD->getAttr<CFReturnsRetainedAttr>()) { 1163 Template->setRetEffect(RetEffect::MakeOwned(RetEffect::CF, true)); 1164 } 1165 else if (FD->getAttr<NSReturnsNotRetainedAttr>()) { 1166 Template->setRetEffect(RetEffect::MakeNotOwned(RetEffect::ObjC)); 1167 } 1168 else if (FD->getAttr<CFReturnsNotRetainedAttr>()) { 1169 Template->setRetEffect(RetEffect::MakeNotOwned(RetEffect::CF)); 1170 } 1171 } else if (RetTy->getAs<PointerType>()) { 1172 if (FD->getAttr<CFReturnsRetainedAttr>()) { 1173 Template->setRetEffect(RetEffect::MakeOwned(RetEffect::CF, true)); 1174 } 1175 else if (FD->getAttr<CFReturnsNotRetainedAttr>()) { 1176 Template->setRetEffect(RetEffect::MakeNotOwned(RetEffect::CF)); 1177 } 1178 } 1179} 1180 1181void 1182RetainSummaryManager::updateSummaryFromAnnotations(RetainSummary *&Summ, 1183 const ObjCMethodDecl *MD) { 1184 if (!MD) 1185 return; 1186 1187 RetainSummaryTemplate Template(Summ, DefaultSummary, *this); 1188 1189 bool isTrackedLoc = false; 1190 1191 // Effects on the receiver. 1192 if (MD->getAttr<NSConsumesSelfAttr>()) { 1193 if (!GCEnabled) 1194 Template->setReceiverEffect(DecRefMsg); 1195 } 1196 1197 // Effects on the parameters. 1198 unsigned parm_idx = 0; 1199 for (ObjCMethodDecl::param_const_iterator 1200 pi=MD->param_begin(), pe=MD->param_end(); 1201 pi != pe; ++pi, ++parm_idx) { 1202 const ParmVarDecl *pd = *pi; 1203 if (pd->getAttr<NSConsumedAttr>()) { 1204 if (!GCEnabled) 1205 Template->addArg(AF, parm_idx, DecRef); 1206 } 1207 else if(pd->getAttr<CFConsumedAttr>()) { 1208 Template->addArg(AF, parm_idx, DecRef); 1209 } 1210 } 1211 1212 // Determine if there is a special return effect for this method. 1213 if (cocoa::isCocoaObjectRef(MD->getResultType())) { 1214 if (MD->getAttr<NSReturnsRetainedAttr>()) { 1215 Template->setRetEffect(ObjCAllocRetE); 1216 return; 1217 } 1218 if (MD->getAttr<NSReturnsNotRetainedAttr>()) { 1219 Template->setRetEffect(RetEffect::MakeNotOwned(RetEffect::ObjC)); 1220 return; 1221 } 1222 1223 isTrackedLoc = true; 1224 } else { 1225 isTrackedLoc = MD->getResultType()->getAs<PointerType>() != NULL; 1226 } 1227 1228 if (isTrackedLoc) { 1229 if (MD->getAttr<CFReturnsRetainedAttr>()) 1230 Template->setRetEffect(RetEffect::MakeOwned(RetEffect::CF, true)); 1231 else if (MD->getAttr<CFReturnsNotRetainedAttr>()) 1232 Template->setRetEffect(RetEffect::MakeNotOwned(RetEffect::CF)); 1233 } 1234} 1235 1236RetainSummary* 1237RetainSummaryManager::getCommonMethodSummary(const ObjCMethodDecl *MD, 1238 Selector S, QualType RetTy) { 1239 1240 if (MD) { 1241 // Scan the method decl for 'void*' arguments. These should be treated 1242 // as 'StopTracking' because they are often used with delegates. 1243 // Delegates are a frequent form of false positives with the retain 1244 // count checker. 1245 unsigned i = 0; 1246 for (ObjCMethodDecl::param_const_iterator I = MD->param_begin(), 1247 E = MD->param_end(); I != E; ++I, ++i) 1248 if (const ParmVarDecl *PD = *I) { 1249 QualType Ty = Ctx.getCanonicalType(PD->getType()); 1250 if (Ty.getLocalUnqualifiedType() == Ctx.VoidPtrTy) 1251 ScratchArgs = AF.add(ScratchArgs, i, StopTracking); 1252 } 1253 } 1254 1255 // Any special effect for the receiver? 1256 ArgEffect ReceiverEff = DoNothing; 1257 1258 // If one of the arguments in the selector has the keyword 'delegate' we 1259 // should stop tracking the reference count for the receiver. This is 1260 // because the reference count is quite possibly handled by a delegate 1261 // method. 1262 if (S.isKeywordSelector()) { 1263 const std::string &str = S.getAsString(); 1264 assert(!str.empty()); 1265 if (StrInStrNoCase(str, "delegate:") != StringRef::npos) 1266 ReceiverEff = StopTracking; 1267 } 1268 1269 // Look for methods that return an owned object. 1270 if (cocoa::isCocoaObjectRef(RetTy)) { 1271 // EXPERIMENTAL: assume the Cocoa conventions for all objects returned 1272 // by instance methods. 1273 RetEffect E = cocoa::followsFundamentalRule(S, MD) 1274 ? ObjCAllocRetE : RetEffect::MakeNotOwned(RetEffect::ObjC); 1275 1276 return getPersistentSummary(E, ReceiverEff, MayEscape); 1277 } 1278 1279 // Look for methods that return an owned core foundation object. 1280 if (coreFoundation::isCFObjectRef(RetTy)) { 1281 RetEffect E = cocoa::followsFundamentalRule(S, MD) 1282 ? RetEffect::MakeOwned(RetEffect::CF, true) 1283 : RetEffect::MakeNotOwned(RetEffect::CF); 1284 1285 return getPersistentSummary(E, ReceiverEff, MayEscape); 1286 } 1287 1288 if (ScratchArgs.isEmpty() && ReceiverEff == DoNothing) 1289 return 0; 1290 1291 return getPersistentSummary(RetEffect::MakeNoRet(), ReceiverEff, MayEscape); 1292} 1293 1294RetainSummary* 1295RetainSummaryManager::getInstanceMethodSummary(const ObjCMessage &msg, 1296 const ProgramState *state, 1297 const LocationContext *LC) { 1298 1299 // We need the type-information of the tracked receiver object 1300 // Retrieve it from the state. 1301 const Expr *Receiver = msg.getInstanceReceiver(); 1302 const ObjCInterfaceDecl *ID = 0; 1303 1304 // FIXME: Is this really working as expected? There are cases where 1305 // we just use the 'ID' from the message expression. 1306 SVal receiverV; 1307 1308 if (Receiver) { 1309 receiverV = state->getSValAsScalarOrLoc(Receiver); 1310 1311 // FIXME: Eventually replace the use of state->get<RefBindings> with 1312 // a generic API for reasoning about the Objective-C types of symbolic 1313 // objects. 1314 if (SymbolRef Sym = receiverV.getAsLocSymbol()) 1315 if (const RefVal *T = state->get<RefBindings>(Sym)) 1316 if (const ObjCObjectPointerType* PT = 1317 T->getType()->getAs<ObjCObjectPointerType>()) 1318 ID = PT->getInterfaceDecl(); 1319 1320 // FIXME: this is a hack. This may or may not be the actual method 1321 // that is called. 1322 if (!ID) { 1323 if (const ObjCObjectPointerType *PT = 1324 Receiver->getType()->getAs<ObjCObjectPointerType>()) 1325 ID = PT->getInterfaceDecl(); 1326 } 1327 } else { 1328 // FIXME: Hack for 'super'. 1329 ID = msg.getReceiverInterface(); 1330 } 1331 1332 // FIXME: The receiver could be a reference to a class, meaning that 1333 // we should use the class method. 1334 return getInstanceMethodSummary(msg, ID); 1335} 1336 1337RetainSummary* 1338RetainSummaryManager::getInstanceMethodSummary(Selector S, 1339 IdentifierInfo *ClsName, 1340 const ObjCInterfaceDecl *ID, 1341 const ObjCMethodDecl *MD, 1342 QualType RetTy) { 1343 1344 // Look up a summary in our summary cache. 1345 RetainSummary *Summ = ObjCMethodSummaries.find(ID, ClsName, S); 1346 1347 if (!Summ) { 1348 assert(ScratchArgs.isEmpty()); 1349 1350 // "initXXX": pass-through for receiver. 1351 if (cocoa::deriveNamingConvention(S, MD) == cocoa::InitRule) 1352 Summ = getInitMethodSummary(RetTy); 1353 else 1354 Summ = getCommonMethodSummary(MD, S, RetTy); 1355 1356 // Annotations override defaults. 1357 updateSummaryFromAnnotations(Summ, MD); 1358 1359 // Memoize the summary. 1360 ObjCMethodSummaries[ObjCSummaryKey(ID, ClsName, S)] = Summ; 1361 } 1362 1363 return Summ; 1364} 1365 1366RetainSummary* 1367RetainSummaryManager::getClassMethodSummary(Selector S, IdentifierInfo *ClsName, 1368 const ObjCInterfaceDecl *ID, 1369 const ObjCMethodDecl *MD, 1370 QualType RetTy) { 1371 1372 assert(ClsName && "Class name must be specified."); 1373 RetainSummary *Summ = ObjCClassMethodSummaries.find(ID, ClsName, S); 1374 1375 if (!Summ) { 1376 Summ = getCommonMethodSummary(MD, S, RetTy); 1377 1378 // Annotations override defaults. 1379 updateSummaryFromAnnotations(Summ, MD); 1380 1381 // Memoize the summary. 1382 ObjCClassMethodSummaries[ObjCSummaryKey(ID, ClsName, S)] = Summ; 1383 } 1384 1385 return Summ; 1386} 1387 1388void RetainSummaryManager::InitializeClassMethodSummaries() { 1389 assert(ScratchArgs.isEmpty()); 1390 // Create the [NSAssertionHandler currentHander] summary. 1391 addClassMethSummary("NSAssertionHandler", "currentHandler", 1392 getPersistentSummary(RetEffect::MakeNotOwned(RetEffect::ObjC))); 1393 1394 // Create the [NSAutoreleasePool addObject:] summary. 1395 ScratchArgs = AF.add(ScratchArgs, 0, Autorelease); 1396 addClassMethSummary("NSAutoreleasePool", "addObject", 1397 getPersistentSummary(RetEffect::MakeNoRet(), 1398 DoNothing, Autorelease)); 1399 1400 // Create the summaries for [NSObject performSelector...]. We treat 1401 // these as 'stop tracking' for the arguments because they are often 1402 // used for delegates that can release the object. When we have better 1403 // inter-procedural analysis we can potentially do something better. This 1404 // workaround is to remove false positives. 1405 RetainSummary *Summ = 1406 getPersistentSummary(RetEffect::MakeNoRet(), DoNothing, StopTracking); 1407 IdentifierInfo *NSObjectII = &Ctx.Idents.get("NSObject"); 1408 addClsMethSummary(NSObjectII, Summ, "performSelector", "withObject", 1409 "afterDelay", NULL); 1410 addClsMethSummary(NSObjectII, Summ, "performSelector", "withObject", 1411 "afterDelay", "inModes", NULL); 1412 addClsMethSummary(NSObjectII, Summ, "performSelectorOnMainThread", 1413 "withObject", "waitUntilDone", NULL); 1414 addClsMethSummary(NSObjectII, Summ, "performSelectorOnMainThread", 1415 "withObject", "waitUntilDone", "modes", NULL); 1416 addClsMethSummary(NSObjectII, Summ, "performSelector", "onThread", 1417 "withObject", "waitUntilDone", NULL); 1418 addClsMethSummary(NSObjectII, Summ, "performSelector", "onThread", 1419 "withObject", "waitUntilDone", "modes", NULL); 1420 addClsMethSummary(NSObjectII, Summ, "performSelectorInBackground", 1421 "withObject", NULL); 1422} 1423 1424void RetainSummaryManager::InitializeMethodSummaries() { 1425 1426 assert (ScratchArgs.isEmpty()); 1427 1428 // Create the "init" selector. It just acts as a pass-through for the 1429 // receiver. 1430 RetainSummary *InitSumm = getPersistentSummary(ObjCInitRetE, DecRefMsg); 1431 addNSObjectMethSummary(GetNullarySelector("init", Ctx), InitSumm); 1432 1433 // awakeAfterUsingCoder: behaves basically like an 'init' method. It 1434 // claims the receiver and returns a retained object. 1435 addNSObjectMethSummary(GetUnarySelector("awakeAfterUsingCoder", Ctx), 1436 InitSumm); 1437 1438 // The next methods are allocators. 1439 RetainSummary *AllocSumm = getPersistentSummary(ObjCAllocRetE); 1440 RetainSummary *CFAllocSumm = 1441 getPersistentSummary(RetEffect::MakeOwned(RetEffect::CF, true)); 1442 1443 // Create the "retain" selector. 1444 RetEffect NoRet = RetEffect::MakeNoRet(); 1445 RetainSummary *Summ = getPersistentSummary(NoRet, IncRefMsg); 1446 addNSObjectMethSummary(GetNullarySelector("retain", Ctx), Summ); 1447 1448 // Create the "release" selector. 1449 Summ = getPersistentSummary(NoRet, DecRefMsg); 1450 addNSObjectMethSummary(GetNullarySelector("release", Ctx), Summ); 1451 1452 // Create the "drain" selector. 1453 Summ = getPersistentSummary(NoRet, isGCEnabled() ? DoNothing : DecRef); 1454 addNSObjectMethSummary(GetNullarySelector("drain", Ctx), Summ); 1455 1456 // Create the -dealloc summary. 1457 Summ = getPersistentSummary(NoRet, Dealloc); 1458 addNSObjectMethSummary(GetNullarySelector("dealloc", Ctx), Summ); 1459 1460 // Create the "autorelease" selector. 1461 Summ = getPersistentSummary(NoRet, Autorelease); 1462 addNSObjectMethSummary(GetNullarySelector("autorelease", Ctx), Summ); 1463 1464 // Specially handle NSAutoreleasePool. 1465 addInstMethSummary("NSAutoreleasePool", "init", 1466 getPersistentSummary(NoRet, NewAutoreleasePool)); 1467 1468 // For NSWindow, allocated objects are (initially) self-owned. 1469 // FIXME: For now we opt for false negatives with NSWindow, as these objects 1470 // self-own themselves. However, they only do this once they are displayed. 1471 // Thus, we need to track an NSWindow's display status. 1472 // This is tracked in <rdar://problem/6062711>. 1473 // See also http://llvm.org/bugs/show_bug.cgi?id=3714. 1474 RetainSummary *NoTrackYet = getPersistentSummary(RetEffect::MakeNoRet(), 1475 StopTracking, 1476 StopTracking); 1477 1478 addClassMethSummary("NSWindow", "alloc", NoTrackYet); 1479 1480#if 0 1481 addInstMethSummary("NSWindow", NoTrackYet, "initWithContentRect", 1482 "styleMask", "backing", "defer", NULL); 1483 1484 addInstMethSummary("NSWindow", NoTrackYet, "initWithContentRect", 1485 "styleMask", "backing", "defer", "screen", NULL); 1486#endif 1487 1488 // For NSPanel (which subclasses NSWindow), allocated objects are not 1489 // self-owned. 1490 // FIXME: For now we don't track NSPanels. object for the same reason 1491 // as for NSWindow objects. 1492 addClassMethSummary("NSPanel", "alloc", NoTrackYet); 1493 1494#if 0 1495 addInstMethSummary("NSPanel", NoTrackYet, "initWithContentRect", 1496 "styleMask", "backing", "defer", NULL); 1497 1498 addInstMethSummary("NSPanel", NoTrackYet, "initWithContentRect", 1499 "styleMask", "backing", "defer", "screen", NULL); 1500#endif 1501 1502 // Don't track allocated autorelease pools yet, as it is okay to prematurely 1503 // exit a method. 1504 addClassMethSummary("NSAutoreleasePool", "alloc", NoTrackYet); 1505 1506 // Create summaries QCRenderer/QCView -createSnapShotImageOfType: 1507 addInstMethSummary("QCRenderer", AllocSumm, 1508 "createSnapshotImageOfType", NULL); 1509 addInstMethSummary("QCView", AllocSumm, 1510 "createSnapshotImageOfType", NULL); 1511 1512 // Create summaries for CIContext, 'createCGImage' and 1513 // 'createCGLayerWithSize'. These objects are CF objects, and are not 1514 // automatically garbage collected. 1515 addInstMethSummary("CIContext", CFAllocSumm, 1516 "createCGImage", "fromRect", NULL); 1517 addInstMethSummary("CIContext", CFAllocSumm, 1518 "createCGImage", "fromRect", "format", "colorSpace", NULL); 1519 addInstMethSummary("CIContext", CFAllocSumm, "createCGLayerWithSize", 1520 "info", NULL); 1521} 1522 1523//===----------------------------------------------------------------------===// 1524// AutoreleaseBindings - State used to track objects in autorelease pools. 1525//===----------------------------------------------------------------------===// 1526 1527typedef llvm::ImmutableMap<SymbolRef, unsigned> ARCounts; 1528typedef llvm::ImmutableMap<SymbolRef, ARCounts> ARPoolContents; 1529typedef llvm::ImmutableList<SymbolRef> ARStack; 1530 1531static int AutoRCIndex = 0; 1532static int AutoRBIndex = 0; 1533 1534namespace { class AutoreleasePoolContents {}; } 1535namespace { class AutoreleaseStack {}; } 1536 1537namespace clang { 1538namespace ento { 1539template<> struct ProgramStateTrait<AutoreleaseStack> 1540 : public ProgramStatePartialTrait<ARStack> { 1541 static inline void *GDMIndex() { return &AutoRBIndex; } 1542}; 1543 1544template<> struct ProgramStateTrait<AutoreleasePoolContents> 1545 : public ProgramStatePartialTrait<ARPoolContents> { 1546 static inline void *GDMIndex() { return &AutoRCIndex; } 1547}; 1548} // end GR namespace 1549} // end clang namespace 1550 1551static SymbolRef GetCurrentAutoreleasePool(const ProgramState *state) { 1552 ARStack stack = state->get<AutoreleaseStack>(); 1553 return stack.isEmpty() ? SymbolRef() : stack.getHead(); 1554} 1555 1556static const ProgramState * 1557SendAutorelease(const ProgramState *state, 1558 ARCounts::Factory &F, 1559 SymbolRef sym) { 1560 SymbolRef pool = GetCurrentAutoreleasePool(state); 1561 const ARCounts *cnts = state->get<AutoreleasePoolContents>(pool); 1562 ARCounts newCnts(0); 1563 1564 if (cnts) { 1565 const unsigned *cnt = (*cnts).lookup(sym); 1566 newCnts = F.add(*cnts, sym, cnt ? *cnt + 1 : 1); 1567 } 1568 else 1569 newCnts = F.add(F.getEmptyMap(), sym, 1); 1570 1571 return state->set<AutoreleasePoolContents>(pool, newCnts); 1572} 1573 1574//===----------------------------------------------------------------------===// 1575// Error reporting. 1576//===----------------------------------------------------------------------===// 1577namespace { 1578 typedef llvm::DenseMap<const ExplodedNode *, const RetainSummary *> 1579 SummaryLogTy; 1580 1581 //===-------------===// 1582 // Bug Descriptions. // 1583 //===-------------===// 1584 1585 class CFRefBug : public BugType { 1586 protected: 1587 CFRefBug(StringRef name) 1588 : BugType(name, "Memory (Core Foundation/Objective-C)") {} 1589 public: 1590 1591 // FIXME: Eventually remove. 1592 virtual const char *getDescription() const = 0; 1593 1594 virtual bool isLeak() const { return false; } 1595 }; 1596 1597 class UseAfterRelease : public CFRefBug { 1598 public: 1599 UseAfterRelease() : CFRefBug("Use-after-release") {} 1600 1601 const char *getDescription() const { 1602 return "Reference-counted object is used after it is released"; 1603 } 1604 }; 1605 1606 class BadRelease : public CFRefBug { 1607 public: 1608 BadRelease() : CFRefBug("Bad release") {} 1609 1610 const char *getDescription() const { 1611 return "Incorrect decrement of the reference count of an object that is " 1612 "not owned at this point by the caller"; 1613 } 1614 }; 1615 1616 class DeallocGC : public CFRefBug { 1617 public: 1618 DeallocGC() 1619 : CFRefBug("-dealloc called while using garbage collection") {} 1620 1621 const char *getDescription() const { 1622 return "-dealloc called while using garbage collection"; 1623 } 1624 }; 1625 1626 class DeallocNotOwned : public CFRefBug { 1627 public: 1628 DeallocNotOwned() 1629 : CFRefBug("-dealloc sent to non-exclusively owned object") {} 1630 1631 const char *getDescription() const { 1632 return "-dealloc sent to object that may be referenced elsewhere"; 1633 } 1634 }; 1635 1636 class OverAutorelease : public CFRefBug { 1637 public: 1638 OverAutorelease() 1639 : CFRefBug("Object sent -autorelease too many times") {} 1640 1641 const char *getDescription() const { 1642 return "Object sent -autorelease too many times"; 1643 } 1644 }; 1645 1646 class ReturnedNotOwnedForOwned : public CFRefBug { 1647 public: 1648 ReturnedNotOwnedForOwned() 1649 : CFRefBug("Method should return an owned object") {} 1650 1651 const char *getDescription() const { 1652 return "Object with a +0 retain count returned to caller where a +1 " 1653 "(owning) retain count is expected"; 1654 } 1655 }; 1656 1657 class Leak : public CFRefBug { 1658 const bool isReturn; 1659 protected: 1660 Leak(StringRef name, bool isRet) 1661 : CFRefBug(name), isReturn(isRet) { 1662 // Leaks should not be reported if they are post-dominated by a sink. 1663 setSuppressOnSink(true); 1664 } 1665 public: 1666 1667 const char *getDescription() const { return ""; } 1668 1669 bool isLeak() const { return true; } 1670 }; 1671 1672 class LeakAtReturn : public Leak { 1673 public: 1674 LeakAtReturn(StringRef name) 1675 : Leak(name, true) {} 1676 }; 1677 1678 class LeakWithinFunction : public Leak { 1679 public: 1680 LeakWithinFunction(StringRef name) 1681 : Leak(name, false) {} 1682 }; 1683 1684 //===---------===// 1685 // Bug Reports. // 1686 //===---------===// 1687 1688 class CFRefReportVisitor : public BugReporterVisitor { 1689 protected: 1690 SymbolRef Sym; 1691 const SummaryLogTy &SummaryLog; 1692 bool GCEnabled; 1693 1694 public: 1695 CFRefReportVisitor(SymbolRef sym, bool gcEnabled, const SummaryLogTy &log) 1696 : Sym(sym), SummaryLog(log), GCEnabled(gcEnabled) {} 1697 1698 virtual void Profile(llvm::FoldingSetNodeID &ID) const { 1699 static int x = 0; 1700 ID.AddPointer(&x); 1701 ID.AddPointer(Sym); 1702 } 1703 1704 virtual PathDiagnosticPiece *VisitNode(const ExplodedNode *N, 1705 const ExplodedNode *PrevN, 1706 BugReporterContext &BRC, 1707 BugReport &BR); 1708 1709 virtual PathDiagnosticPiece *getEndPath(BugReporterContext &BRC, 1710 const ExplodedNode *N, 1711 BugReport &BR); 1712 }; 1713 1714 class CFRefLeakReportVisitor : public CFRefReportVisitor { 1715 public: 1716 CFRefLeakReportVisitor(SymbolRef sym, bool GCEnabled, 1717 const SummaryLogTy &log) 1718 : CFRefReportVisitor(sym, GCEnabled, log) {} 1719 1720 PathDiagnosticPiece *getEndPath(BugReporterContext &BRC, 1721 const ExplodedNode *N, 1722 BugReport &BR); 1723 }; 1724 1725 class CFRefReport : public BugReport { 1726 void addGCModeDescription(const LangOptions &LOpts, bool GCEnabled); 1727 1728 public: 1729 CFRefReport(CFRefBug &D, const LangOptions &LOpts, bool GCEnabled, 1730 const SummaryLogTy &Log, ExplodedNode *n, SymbolRef sym, 1731 bool registerVisitor = true) 1732 : BugReport(D, D.getDescription(), n) { 1733 if (registerVisitor) 1734 addVisitor(new CFRefReportVisitor(sym, GCEnabled, Log)); 1735 addGCModeDescription(LOpts, GCEnabled); 1736 } 1737 1738 CFRefReport(CFRefBug &D, const LangOptions &LOpts, bool GCEnabled, 1739 const SummaryLogTy &Log, ExplodedNode *n, SymbolRef sym, 1740 StringRef endText) 1741 : BugReport(D, D.getDescription(), endText, n) { 1742 addVisitor(new CFRefReportVisitor(sym, GCEnabled, Log)); 1743 addGCModeDescription(LOpts, GCEnabled); 1744 } 1745 1746 virtual std::pair<ranges_iterator, ranges_iterator> getRanges() { 1747 const CFRefBug& BugTy = static_cast<CFRefBug&>(getBugType()); 1748 if (!BugTy.isLeak()) 1749 return BugReport::getRanges(); 1750 else 1751 return std::make_pair(ranges_iterator(), ranges_iterator()); 1752 } 1753 }; 1754 1755 class CFRefLeakReport : public CFRefReport { 1756 const MemRegion* AllocBinding; 1757 1758 public: 1759 CFRefLeakReport(CFRefBug &D, const LangOptions &LOpts, bool GCEnabled, 1760 const SummaryLogTy &Log, ExplodedNode *n, SymbolRef sym, 1761 ExprEngine &Eng); 1762 1763 PathDiagnosticLocation getLocation(const SourceManager &SM) const { 1764 assert(Location.isValid()); 1765 return Location; 1766 } 1767 }; 1768} // end anonymous namespace 1769 1770void CFRefReport::addGCModeDescription(const LangOptions &LOpts, 1771 bool GCEnabled) { 1772 const char *GCModeDescription = 0; 1773 1774 switch (LOpts.getGC()) { 1775 case LangOptions::GCOnly: 1776 assert(GCEnabled); 1777 GCModeDescription = "Code is compiled to only use garbage collection"; 1778 break; 1779 1780 case LangOptions::NonGC: 1781 assert(!GCEnabled); 1782 GCModeDescription = "Code is compiled to use reference counts"; 1783 break; 1784 1785 case LangOptions::HybridGC: 1786 if (GCEnabled) { 1787 GCModeDescription = "Code is compiled to use either garbage collection " 1788 "(GC) or reference counts (non-GC). The bug occurs " 1789 "with GC enabled"; 1790 break; 1791 } else { 1792 GCModeDescription = "Code is compiled to use either garbage collection " 1793 "(GC) or reference counts (non-GC). The bug occurs " 1794 "in non-GC mode"; 1795 break; 1796 } 1797 } 1798 1799 assert(GCModeDescription && "invalid/unknown GC mode"); 1800 addExtraText(GCModeDescription); 1801} 1802 1803// FIXME: This should be a method on SmallVector. 1804static inline bool contains(const SmallVectorImpl<ArgEffect>& V, 1805 ArgEffect X) { 1806 for (SmallVectorImpl<ArgEffect>::const_iterator I=V.begin(), E=V.end(); 1807 I!=E; ++I) 1808 if (*I == X) return true; 1809 1810 return false; 1811} 1812 1813PathDiagnosticPiece *CFRefReportVisitor::VisitNode(const ExplodedNode *N, 1814 const ExplodedNode *PrevN, 1815 BugReporterContext &BRC, 1816 BugReport &BR) { 1817 1818 if (!isa<StmtPoint>(N->getLocation())) 1819 return NULL; 1820 1821 // Check if the type state has changed. 1822 const ProgramState *PrevSt = PrevN->getState(); 1823 const ProgramState *CurrSt = N->getState(); 1824 1825 const RefVal* CurrT = CurrSt->get<RefBindings>(Sym); 1826 if (!CurrT) return NULL; 1827 1828 const RefVal &CurrV = *CurrT; 1829 const RefVal *PrevT = PrevSt->get<RefBindings>(Sym); 1830 1831 // Create a string buffer to constain all the useful things we want 1832 // to tell the user. 1833 std::string sbuf; 1834 llvm::raw_string_ostream os(sbuf); 1835 1836 // This is the allocation site since the previous node had no bindings 1837 // for this symbol. 1838 if (!PrevT) { 1839 const Stmt *S = cast<StmtPoint>(N->getLocation()).getStmt(); 1840 1841 if (const CallExpr *CE = dyn_cast<CallExpr>(S)) { 1842 // Get the name of the callee (if it is available). 1843 SVal X = CurrSt->getSValAsScalarOrLoc(CE->getCallee()); 1844 if (const FunctionDecl *FD = X.getAsFunctionDecl()) 1845 os << "Call to function '" << FD << '\''; 1846 else 1847 os << "function call"; 1848 } 1849 else if (isa<ObjCMessageExpr>(S)) { 1850 os << "Method"; 1851 } else { 1852 os << "Property"; 1853 } 1854 1855 if (CurrV.getObjKind() == RetEffect::CF) { 1856 os << " returns a Core Foundation object with a "; 1857 } 1858 else { 1859 assert (CurrV.getObjKind() == RetEffect::ObjC); 1860 os << " returns an Objective-C object with a "; 1861 } 1862 1863 if (CurrV.isOwned()) { 1864 os << "+1 retain count"; 1865 1866 if (GCEnabled) { 1867 assert(CurrV.getObjKind() == RetEffect::CF); 1868 os << ". " 1869 "Core Foundation objects are not automatically garbage collected."; 1870 } 1871 } 1872 else { 1873 assert (CurrV.isNotOwned()); 1874 os << "+0 retain count"; 1875 } 1876 1877 PathDiagnosticLocation Pos(S, BRC.getSourceManager(), 1878 N->getLocationContext()); 1879 return new PathDiagnosticEventPiece(Pos, os.str()); 1880 } 1881 1882 // Gather up the effects that were performed on the object at this 1883 // program point 1884 SmallVector<ArgEffect, 2> AEffects; 1885 1886 const ExplodedNode *OrigNode = BRC.getNodeResolver().getOriginalNode(N); 1887 if (const RetainSummary *Summ = SummaryLog.lookup(OrigNode)) { 1888 // We only have summaries attached to nodes after evaluating CallExpr and 1889 // ObjCMessageExprs. 1890 const Stmt *S = cast<StmtPoint>(N->getLocation()).getStmt(); 1891 1892 if (const CallExpr *CE = dyn_cast<CallExpr>(S)) { 1893 // Iterate through the parameter expressions and see if the symbol 1894 // was ever passed as an argument. 1895 unsigned i = 0; 1896 1897 for (CallExpr::const_arg_iterator AI=CE->arg_begin(), AE=CE->arg_end(); 1898 AI!=AE; ++AI, ++i) { 1899 1900 // Retrieve the value of the argument. Is it the symbol 1901 // we are interested in? 1902 if (CurrSt->getSValAsScalarOrLoc(*AI).getAsLocSymbol() != Sym) 1903 continue; 1904 1905 // We have an argument. Get the effect! 1906 AEffects.push_back(Summ->getArg(i)); 1907 } 1908 } 1909 else if (const ObjCMessageExpr *ME = dyn_cast<ObjCMessageExpr>(S)) { 1910 if (const Expr *receiver = ME->getInstanceReceiver()) 1911 if (CurrSt->getSValAsScalarOrLoc(receiver).getAsLocSymbol() == Sym) { 1912 // The symbol we are tracking is the receiver. 1913 AEffects.push_back(Summ->getReceiverEffect()); 1914 } 1915 } 1916 } 1917 1918 do { 1919 // Get the previous type state. 1920 RefVal PrevV = *PrevT; 1921 1922 // Specially handle -dealloc. 1923 if (!GCEnabled && contains(AEffects, Dealloc)) { 1924 // Determine if the object's reference count was pushed to zero. 1925 assert(!(PrevV == CurrV) && "The typestate *must* have changed."); 1926 // We may not have transitioned to 'release' if we hit an error. 1927 // This case is handled elsewhere. 1928 if (CurrV.getKind() == RefVal::Released) { 1929 assert(CurrV.getCombinedCounts() == 0); 1930 os << "Object released by directly sending the '-dealloc' message"; 1931 break; 1932 } 1933 } 1934 1935 // Specially handle CFMakeCollectable and friends. 1936 if (contains(AEffects, MakeCollectable)) { 1937 // Get the name of the function. 1938 const Stmt *S = cast<StmtPoint>(N->getLocation()).getStmt(); 1939 SVal X = CurrSt->getSValAsScalarOrLoc(cast<CallExpr>(S)->getCallee()); 1940 const FunctionDecl *FD = X.getAsFunctionDecl(); 1941 1942 if (GCEnabled) { 1943 // Determine if the object's reference count was pushed to zero. 1944 assert(!(PrevV == CurrV) && "The typestate *must* have changed."); 1945 1946 os << "In GC mode a call to '" << FD 1947 << "' decrements an object's retain count and registers the " 1948 "object with the garbage collector. "; 1949 1950 if (CurrV.getKind() == RefVal::Released) { 1951 assert(CurrV.getCount() == 0); 1952 os << "Since it now has a 0 retain count the object can be " 1953 "automatically collected by the garbage collector."; 1954 } 1955 else 1956 os << "An object must have a 0 retain count to be garbage collected. " 1957 "After this call its retain count is +" << CurrV.getCount() 1958 << '.'; 1959 } 1960 else 1961 os << "When GC is not enabled a call to '" << FD 1962 << "' has no effect on its argument."; 1963 1964 // Nothing more to say. 1965 break; 1966 } 1967 1968 // Determine if the typestate has changed. 1969 if (!(PrevV == CurrV)) 1970 switch (CurrV.getKind()) { 1971 case RefVal::Owned: 1972 case RefVal::NotOwned: 1973 1974 if (PrevV.getCount() == CurrV.getCount()) { 1975 // Did an autorelease message get sent? 1976 if (PrevV.getAutoreleaseCount() == CurrV.getAutoreleaseCount()) 1977 return 0; 1978 1979 assert(PrevV.getAutoreleaseCount() < CurrV.getAutoreleaseCount()); 1980 os << "Object sent -autorelease message"; 1981 break; 1982 } 1983 1984 if (PrevV.getCount() > CurrV.getCount()) 1985 os << "Reference count decremented."; 1986 else 1987 os << "Reference count incremented."; 1988 1989 if (unsigned Count = CurrV.getCount()) 1990 os << " The object now has a +" << Count << " retain count."; 1991 1992 if (PrevV.getKind() == RefVal::Released) { 1993 assert(GCEnabled && CurrV.getCount() > 0); 1994 os << " The object is not eligible for garbage collection until the " 1995 "retain count reaches 0 again."; 1996 } 1997 1998 break; 1999 2000 case RefVal::Released: 2001 os << "Object released."; 2002 break; 2003 2004 case RefVal::ReturnedOwned: 2005 os << "Object returned to caller as an owning reference (single retain " 2006 "count transferred to caller)"; 2007 break; 2008 2009 case RefVal::ReturnedNotOwned: 2010 os << "Object returned to caller with a +0 retain count"; 2011 break; 2012 2013 default: 2014 return NULL; 2015 } 2016 2017 // Emit any remaining diagnostics for the argument effects (if any). 2018 for (SmallVectorImpl<ArgEffect>::iterator I=AEffects.begin(), 2019 E=AEffects.end(); I != E; ++I) { 2020 2021 // A bunch of things have alternate behavior under GC. 2022 if (GCEnabled) 2023 switch (*I) { 2024 default: break; 2025 case Autorelease: 2026 os << "In GC mode an 'autorelease' has no effect."; 2027 continue; 2028 case IncRefMsg: 2029 os << "In GC mode the 'retain' message has no effect."; 2030 continue; 2031 case DecRefMsg: 2032 os << "In GC mode the 'release' message has no effect."; 2033 continue; 2034 } 2035 } 2036 } while (0); 2037 2038 if (os.str().empty()) 2039 return 0; // We have nothing to say! 2040 2041 const Stmt *S = cast<StmtPoint>(N->getLocation()).getStmt(); 2042 PathDiagnosticLocation Pos(S, BRC.getSourceManager(), 2043 N->getLocationContext()); 2044 PathDiagnosticPiece *P = new PathDiagnosticEventPiece(Pos, os.str()); 2045 2046 // Add the range by scanning the children of the statement for any bindings 2047 // to Sym. 2048 for (Stmt::const_child_iterator I = S->child_begin(), E = S->child_end(); 2049 I!=E; ++I) 2050 if (const Expr *Exp = dyn_cast_or_null<Expr>(*I)) 2051 if (CurrSt->getSValAsScalarOrLoc(Exp).getAsLocSymbol() == Sym) { 2052 P->addRange(Exp->getSourceRange()); 2053 break; 2054 } 2055 2056 return P; 2057} 2058 2059namespace { 2060 class FindUniqueBinding : 2061 public StoreManager::BindingsHandler { 2062 SymbolRef Sym; 2063 const MemRegion* Binding; 2064 bool First; 2065 2066 public: 2067 FindUniqueBinding(SymbolRef sym) : Sym(sym), Binding(0), First(true) {} 2068 2069 bool HandleBinding(StoreManager& SMgr, Store store, const MemRegion* R, 2070 SVal val) { 2071 2072 SymbolRef SymV = val.getAsSymbol(); 2073 if (!SymV || SymV != Sym) 2074 return true; 2075 2076 if (Binding) { 2077 First = false; 2078 return false; 2079 } 2080 else 2081 Binding = R; 2082 2083 return true; 2084 } 2085 2086 operator bool() { return First && Binding; } 2087 const MemRegion* getRegion() { return Binding; } 2088 }; 2089} 2090 2091static std::pair<const ExplodedNode*,const MemRegion*> 2092GetAllocationSite(ProgramStateManager& StateMgr, const ExplodedNode *N, 2093 SymbolRef Sym) { 2094 2095 // Find both first node that referred to the tracked symbol and the 2096 // memory location that value was store to. 2097 const ExplodedNode *Last = N; 2098 const MemRegion* FirstBinding = 0; 2099 2100 while (N) { 2101 const ProgramState *St = N->getState(); 2102 RefBindings B = St->get<RefBindings>(); 2103 2104 if (!B.lookup(Sym)) 2105 break; 2106 2107 FindUniqueBinding FB(Sym); 2108 StateMgr.iterBindings(St, FB); 2109 if (FB) FirstBinding = FB.getRegion(); 2110 2111 Last = N; 2112 N = N->pred_empty() ? NULL : *(N->pred_begin()); 2113 } 2114 2115 return std::make_pair(Last, FirstBinding); 2116} 2117 2118PathDiagnosticPiece* 2119CFRefReportVisitor::getEndPath(BugReporterContext &BRC, 2120 const ExplodedNode *EndN, 2121 BugReport &BR) { 2122 // Tell the BugReporterContext to report cases when the tracked symbol is 2123 // assigned to different variables, etc. 2124 BRC.addNotableSymbol(Sym); 2125 return BugReporterVisitor::getDefaultEndPath(BRC, EndN, BR); 2126} 2127 2128PathDiagnosticPiece* 2129CFRefLeakReportVisitor::getEndPath(BugReporterContext &BRC, 2130 const ExplodedNode *EndN, 2131 BugReport &BR) { 2132 2133 // Tell the BugReporterContext to report cases when the tracked symbol is 2134 // assigned to different variables, etc. 2135 BRC.addNotableSymbol(Sym); 2136 2137 // We are reporting a leak. Walk up the graph to get to the first node where 2138 // the symbol appeared, and also get the first VarDecl that tracked object 2139 // is stored to. 2140 const ExplodedNode *AllocNode = 0; 2141 const MemRegion* FirstBinding = 0; 2142 2143 llvm::tie(AllocNode, FirstBinding) = 2144 GetAllocationSite(BRC.getStateManager(), EndN, Sym); 2145 2146 SourceManager& SM = BRC.getSourceManager(); 2147 2148 // Compute an actual location for the leak. Sometimes a leak doesn't 2149 // occur at an actual statement (e.g., transition between blocks; end 2150 // of function) so we need to walk the graph and compute a real location. 2151 const ExplodedNode *LeakN = EndN; 2152 PathDiagnosticLocation L = PathDiagnosticLocation::createEndOfPath(LeakN, SM); 2153 2154 std::string sbuf; 2155 llvm::raw_string_ostream os(sbuf); 2156 2157 os << "Object leaked: "; 2158 2159 if (FirstBinding) { 2160 os << "object allocated and stored into '" 2161 << FirstBinding->getString() << '\''; 2162 } 2163 else 2164 os << "allocated object"; 2165 2166 // Get the retain count. 2167 const RefVal* RV = EndN->getState()->get<RefBindings>(Sym); 2168 2169 if (RV->getKind() == RefVal::ErrorLeakReturned) { 2170 // FIXME: Per comments in rdar://6320065, "create" only applies to CF 2171 // objects. Only "copy", "alloc", "retain" and "new" transfer ownership 2172 // to the caller for NS objects. 2173 const Decl *D = &EndN->getCodeDecl(); 2174 if (const ObjCMethodDecl *MD = dyn_cast<ObjCMethodDecl>(D)) { 2175 os << " is returned from a method whose name ('" 2176 << MD->getSelector().getAsString() 2177 << "') does not start with 'copy', 'mutableCopy', 'alloc' or 'new'." 2178 " This violates the naming convention rules" 2179 " given in the Memory Management Guide for Cocoa"; 2180 } 2181 else { 2182 const FunctionDecl *FD = cast<FunctionDecl>(D); 2183 os << " is return from a function whose name ('" 2184 << FD->getNameAsString() 2185 << "') does not contain 'Copy' or 'Create'. This violates the naming" 2186 " convention rules given the Memory Management Guide for Core" 2187 " Foundation"; 2188 } 2189 } 2190 else if (RV->getKind() == RefVal::ErrorGCLeakReturned) { 2191 ObjCMethodDecl &MD = cast<ObjCMethodDecl>(EndN->getCodeDecl()); 2192 os << " and returned from method '" << MD.getSelector().getAsString() 2193 << "' is potentially leaked when using garbage collection. Callers " 2194 "of this method do not expect a returned object with a +1 retain " 2195 "count since they expect the object to be managed by the garbage " 2196 "collector"; 2197 } 2198 else 2199 os << " is not referenced later in this execution path and has a retain " 2200 "count of +" << RV->getCount(); 2201 2202 return new PathDiagnosticEventPiece(L, os.str()); 2203} 2204 2205CFRefLeakReport::CFRefLeakReport(CFRefBug &D, const LangOptions &LOpts, 2206 bool GCEnabled, const SummaryLogTy &Log, 2207 ExplodedNode *n, SymbolRef sym, 2208 ExprEngine &Eng) 2209: CFRefReport(D, LOpts, GCEnabled, Log, n, sym, false) { 2210 2211 // Most bug reports are cached at the location where they occurred. 2212 // With leaks, we want to unique them by the location where they were 2213 // allocated, and only report a single path. To do this, we need to find 2214 // the allocation site of a piece of tracked memory, which we do via a 2215 // call to GetAllocationSite. This will walk the ExplodedGraph backwards. 2216 // Note that this is *not* the trimmed graph; we are guaranteed, however, 2217 // that all ancestor nodes that represent the allocation site have the 2218 // same SourceLocation. 2219 const ExplodedNode *AllocNode = 0; 2220 2221 const SourceManager& SMgr = Eng.getContext().getSourceManager(); 2222 2223 llvm::tie(AllocNode, AllocBinding) = // Set AllocBinding. 2224 GetAllocationSite(Eng.getStateManager(), getErrorNode(), sym); 2225 2226 // Get the SourceLocation for the allocation site. 2227 ProgramPoint P = AllocNode->getLocation(); 2228 const Stmt *AllocStmt = cast<PostStmt>(P).getStmt(); 2229 Location = PathDiagnosticLocation::createBegin(AllocStmt, SMgr, 2230 n->getLocationContext()); 2231 // Fill in the description of the bug. 2232 Description.clear(); 2233 llvm::raw_string_ostream os(Description); 2234 unsigned AllocLine = SMgr.getExpansionLineNumber(AllocStmt->getLocStart()); 2235 os << "Potential leak "; 2236 if (GCEnabled) 2237 os << "(when using garbage collection) "; 2238 os << "of an object allocated on line " << AllocLine; 2239 2240 // FIXME: AllocBinding doesn't get populated for RegionStore yet. 2241 if (AllocBinding) 2242 os << " and stored into '" << AllocBinding->getString() << '\''; 2243 2244 addVisitor(new CFRefLeakReportVisitor(sym, GCEnabled, Log)); 2245} 2246 2247//===----------------------------------------------------------------------===// 2248// Main checker logic. 2249//===----------------------------------------------------------------------===// 2250 2251namespace { 2252class RetainCountChecker 2253 : public Checker< check::Bind, 2254 check::DeadSymbols, 2255 check::EndAnalysis, 2256 check::EndPath, 2257 check::PostStmt<BlockExpr>, 2258 check::PostStmt<CastExpr>, 2259 check::PostStmt<CallExpr>, 2260 check::PostStmt<CXXConstructExpr>, 2261 check::PostObjCMessage, 2262 check::PreStmt<ReturnStmt>, 2263 check::RegionChanges, 2264 eval::Assume, 2265 eval::Call > { 2266 mutable llvm::OwningPtr<CFRefBug> useAfterRelease, releaseNotOwned; 2267 mutable llvm::OwningPtr<CFRefBug> deallocGC, deallocNotOwned; 2268 mutable llvm::OwningPtr<CFRefBug> overAutorelease, returnNotOwnedForOwned; 2269 mutable llvm::OwningPtr<CFRefBug> leakWithinFunction, leakAtReturn; 2270 mutable llvm::OwningPtr<CFRefBug> leakWithinFunctionGC, leakAtReturnGC; 2271 2272 typedef llvm::DenseMap<SymbolRef, const SimpleProgramPointTag *> SymbolTagMap; 2273 2274 // This map is only used to ensure proper deletion of any allocated tags. 2275 mutable SymbolTagMap DeadSymbolTags; 2276 2277 mutable llvm::OwningPtr<RetainSummaryManager> Summaries; 2278 mutable llvm::OwningPtr<RetainSummaryManager> SummariesGC; 2279 2280 mutable ARCounts::Factory ARCountFactory; 2281 2282 mutable SummaryLogTy SummaryLog; 2283 mutable bool ShouldResetSummaryLog; 2284 2285public: 2286 RetainCountChecker() : ShouldResetSummaryLog(false) {} 2287 2288 virtual ~RetainCountChecker() { 2289 DeleteContainerSeconds(DeadSymbolTags); 2290 } 2291 2292 void checkEndAnalysis(ExplodedGraph &G, BugReporter &BR, 2293 ExprEngine &Eng) const { 2294 // FIXME: This is a hack to make sure the summary log gets cleared between 2295 // analyses of different code bodies. 2296 // 2297 // Why is this necessary? Because a checker's lifetime is tied to a 2298 // translation unit, but an ExplodedGraph's lifetime is just a code body. 2299 // Once in a blue moon, a new ExplodedNode will have the same address as an 2300 // old one with an associated summary, and the bug report visitor gets very 2301 // confused. (To make things worse, the summary lifetime is currently also 2302 // tied to a code body, so we get a crash instead of incorrect results.) 2303 // 2304 // Why is this a bad solution? Because if the lifetime of the ExplodedGraph 2305 // changes, things will start going wrong again. Really the lifetime of this 2306 // log needs to be tied to either the specific nodes in it or the entire 2307 // ExplodedGraph, not to a specific part of the code being analyzed. 2308 // 2309 // (Also, having stateful local data means that the same checker can't be 2310 // used from multiple threads, but a lot of checkers have incorrect 2311 // assumptions about that anyway. So that wasn't a priority at the time of 2312 // this fix.) 2313 // 2314 // This happens at the end of analysis, but bug reports are emitted /after/ 2315 // this point. So we can't just clear the summary log now. Instead, we mark 2316 // that the next time we access the summary log, it should be cleared. 2317 2318 // If we never reset the summary log during /this/ code body analysis, 2319 // there were no new summaries. There might still have been summaries from 2320 // the /last/ analysis, so clear them out to make sure the bug report 2321 // visitors don't get confused. 2322 if (ShouldResetSummaryLog) 2323 SummaryLog.clear(); 2324 2325 ShouldResetSummaryLog = !SummaryLog.empty(); 2326 } 2327 2328 CFRefBug *getLeakWithinFunctionBug(const LangOptions &LOpts, 2329 bool GCEnabled) const { 2330 if (GCEnabled) { 2331 if (!leakWithinFunctionGC) 2332 leakWithinFunctionGC.reset(new LeakWithinFunction("Leak of object when " 2333 "using garbage " 2334 "collection")); 2335 return leakWithinFunctionGC.get(); 2336 } else { 2337 if (!leakWithinFunction) { 2338 if (LOpts.getGC() == LangOptions::HybridGC) { 2339 leakWithinFunction.reset(new LeakWithinFunction("Leak of object when " 2340 "not using garbage " 2341 "collection (GC) in " 2342 "dual GC/non-GC " 2343 "code")); 2344 } else { 2345 leakWithinFunction.reset(new LeakWithinFunction("Leak")); 2346 } 2347 } 2348 return leakWithinFunction.get(); 2349 } 2350 } 2351 2352 CFRefBug *getLeakAtReturnBug(const LangOptions &LOpts, bool GCEnabled) const { 2353 if (GCEnabled) { 2354 if (!leakAtReturnGC) 2355 leakAtReturnGC.reset(new LeakAtReturn("Leak of returned object when " 2356 "using garbage collection")); 2357 return leakAtReturnGC.get(); 2358 } else { 2359 if (!leakAtReturn) { 2360 if (LOpts.getGC() == LangOptions::HybridGC) { 2361 leakAtReturn.reset(new LeakAtReturn("Leak of returned object when " 2362 "not using garbage collection " 2363 "(GC) in dual GC/non-GC code")); 2364 } else { 2365 leakAtReturn.reset(new LeakAtReturn("Leak of returned object")); 2366 } 2367 } 2368 return leakAtReturn.get(); 2369 } 2370 } 2371 2372 RetainSummaryManager &getSummaryManager(ASTContext &Ctx, 2373 bool GCEnabled) const { 2374 // FIXME: We don't support ARC being turned on and off during one analysis. 2375 // (nor, for that matter, do we support changing ASTContexts) 2376 bool ARCEnabled = (bool)Ctx.getLangOptions().ObjCAutoRefCount; 2377 if (GCEnabled) { 2378 if (!SummariesGC) 2379 SummariesGC.reset(new RetainSummaryManager(Ctx, true, ARCEnabled)); 2380 else 2381 assert(SummariesGC->isARCEnabled() == ARCEnabled); 2382 return *SummariesGC; 2383 } else { 2384 if (!Summaries) 2385 Summaries.reset(new RetainSummaryManager(Ctx, false, ARCEnabled)); 2386 else 2387 assert(Summaries->isARCEnabled() == ARCEnabled); 2388 return *Summaries; 2389 } 2390 } 2391 2392 RetainSummaryManager &getSummaryManager(CheckerContext &C) const { 2393 return getSummaryManager(C.getASTContext(), C.isObjCGCEnabled()); 2394 } 2395 2396 void printState(raw_ostream &Out, const ProgramState *State, 2397 const char *NL, const char *Sep) const; 2398 2399 void checkBind(SVal loc, SVal val, CheckerContext &C) const; 2400 void checkPostStmt(const BlockExpr *BE, CheckerContext &C) const; 2401 void checkPostStmt(const CastExpr *CE, CheckerContext &C) const; 2402 2403 void checkPostStmt(const CallExpr *CE, CheckerContext &C) const; 2404 void checkPostStmt(const CXXConstructExpr *CE, CheckerContext &C) const; 2405 void checkPostObjCMessage(const ObjCMessage &Msg, CheckerContext &C) const; 2406 void checkSummary(const RetainSummary &Summ, const CallOrObjCMessage &Call, 2407 CheckerContext &C) const; 2408 2409 bool evalCall(const CallExpr *CE, CheckerContext &C) const; 2410 2411 const ProgramState *evalAssume(const ProgramState *state, SVal Cond, 2412 bool Assumption) const; 2413 2414 const ProgramState * 2415 checkRegionChanges(const ProgramState *state, 2416 const StoreManager::InvalidatedSymbols *invalidated, 2417 ArrayRef<const MemRegion *> ExplicitRegions, 2418 ArrayRef<const MemRegion *> Regions) const; 2419 2420 bool wantsRegionChangeUpdate(const ProgramState *state) const { 2421 return true; 2422 } 2423 2424 void checkPreStmt(const ReturnStmt *S, CheckerContext &C) const; 2425 void checkReturnWithRetEffect(const ReturnStmt *S, CheckerContext &C, 2426 ExplodedNode *Pred, RetEffect RE, RefVal X, 2427 SymbolRef Sym, const ProgramState *state) const; 2428 2429 void checkDeadSymbols(SymbolReaper &SymReaper, CheckerContext &C) const; 2430 void checkEndPath(EndOfFunctionNodeBuilder &Builder, ExprEngine &Eng) const; 2431 2432 const ProgramState *updateSymbol(const ProgramState *state, SymbolRef sym, 2433 RefVal V, ArgEffect E, RefVal::Kind &hasErr, 2434 CheckerContext &C) const; 2435 2436 void processNonLeakError(const ProgramState *St, SourceRange ErrorRange, 2437 RefVal::Kind ErrorKind, SymbolRef Sym, 2438 CheckerContext &C) const; 2439 2440 const ProgramPointTag *getDeadSymbolTag(SymbolRef sym) const; 2441 2442 const ProgramState *handleSymbolDeath(const ProgramState *state, 2443 SymbolRef sid, RefVal V, 2444 SmallVectorImpl<SymbolRef> &Leaked) const; 2445 2446 std::pair<ExplodedNode *, const ProgramState *> 2447 handleAutoreleaseCounts(const ProgramState *state, 2448 GenericNodeBuilderRefCount Bd, ExplodedNode *Pred, 2449 ExprEngine &Eng, SymbolRef Sym, RefVal V) const; 2450 2451 ExplodedNode *processLeaks(const ProgramState *state, 2452 SmallVectorImpl<SymbolRef> &Leaked, 2453 GenericNodeBuilderRefCount &Builder, 2454 ExprEngine &Eng, 2455 ExplodedNode *Pred = 0) const; 2456}; 2457} // end anonymous namespace 2458 2459namespace { 2460class StopTrackingCallback : public SymbolVisitor { 2461 const ProgramState *state; 2462public: 2463 StopTrackingCallback(const ProgramState *st) : state(st) {} 2464 const ProgramState *getState() const { return state; } 2465 2466 bool VisitSymbol(SymbolRef sym) { 2467 state = state->remove<RefBindings>(sym); 2468 return true; 2469 } 2470}; 2471} // end anonymous namespace 2472 2473//===----------------------------------------------------------------------===// 2474// Handle statements that may have an effect on refcounts. 2475//===----------------------------------------------------------------------===// 2476 2477void RetainCountChecker::checkPostStmt(const BlockExpr *BE, 2478 CheckerContext &C) const { 2479 2480 // Scan the BlockDecRefExprs for any object the retain count checker 2481 // may be tracking. 2482 if (!BE->getBlockDecl()->hasCaptures()) 2483 return; 2484 2485 const ProgramState *state = C.getState(); 2486 const BlockDataRegion *R = 2487 cast<BlockDataRegion>(state->getSVal(BE).getAsRegion()); 2488 2489 BlockDataRegion::referenced_vars_iterator I = R->referenced_vars_begin(), 2490 E = R->referenced_vars_end(); 2491 2492 if (I == E) 2493 return; 2494 2495 // FIXME: For now we invalidate the tracking of all symbols passed to blocks 2496 // via captured variables, even though captured variables result in a copy 2497 // and in implicit increment/decrement of a retain count. 2498 SmallVector<const MemRegion*, 10> Regions; 2499 const LocationContext *LC = C.getPredecessor()->getLocationContext(); 2500 MemRegionManager &MemMgr = C.getSValBuilder().getRegionManager(); 2501 2502 for ( ; I != E; ++I) { 2503 const VarRegion *VR = *I; 2504 if (VR->getSuperRegion() == R) { 2505 VR = MemMgr.getVarRegion(VR->getDecl(), LC); 2506 } 2507 Regions.push_back(VR); 2508 } 2509 2510 state = 2511 state->scanReachableSymbols<StopTrackingCallback>(Regions.data(), 2512 Regions.data() + Regions.size()).getState(); 2513 C.addTransition(state); 2514} 2515 2516void RetainCountChecker::checkPostStmt(const CastExpr *CE, 2517 CheckerContext &C) const { 2518 const ObjCBridgedCastExpr *BE = dyn_cast<ObjCBridgedCastExpr>(CE); 2519 if (!BE) 2520 return; 2521 2522 ArgEffect AE = IncRef; 2523 2524 switch (BE->getBridgeKind()) { 2525 case clang::OBC_Bridge: 2526 // Do nothing. 2527 return; 2528 case clang::OBC_BridgeRetained: 2529 AE = IncRef; 2530 break; 2531 case clang::OBC_BridgeTransfer: 2532 AE = DecRefBridgedTransfered; 2533 break; 2534 } 2535 2536 const ProgramState *state = C.getState(); 2537 SymbolRef Sym = state->getSVal(CE).getAsLocSymbol(); 2538 if (!Sym) 2539 return; 2540 const RefVal* T = state->get<RefBindings>(Sym); 2541 if (!T) 2542 return; 2543 2544 RefVal::Kind hasErr = (RefVal::Kind) 0; 2545 state = updateSymbol(state, Sym, *T, AE, hasErr, C); 2546 2547 if (hasErr) { 2548 // FIXME: If we get an error during a bridge cast, should we report it? 2549 // Should we assert that there is no error? 2550 return; 2551 } 2552 2553 C.generateNode(state); 2554} 2555 2556void RetainCountChecker::checkPostStmt(const CallExpr *CE, 2557 CheckerContext &C) const { 2558 // Get the callee. 2559 const ProgramState *state = C.getState(); 2560 const Expr *Callee = CE->getCallee(); 2561 SVal L = state->getSVal(Callee); 2562 2563 RetainSummaryManager &Summaries = getSummaryManager(C); 2564 RetainSummary *Summ = 0; 2565 2566 // FIXME: Better support for blocks. For now we stop tracking anything 2567 // that is passed to blocks. 2568 // FIXME: Need to handle variables that are "captured" by the block. 2569 if (dyn_cast_or_null<BlockDataRegion>(L.getAsRegion())) { 2570 Summ = Summaries.getPersistentStopSummary(); 2571 } else if (const FunctionDecl *FD = L.getAsFunctionDecl()) { 2572 Summ = Summaries.getSummary(FD); 2573 } else if (const CXXMemberCallExpr *me = dyn_cast<CXXMemberCallExpr>(CE)) { 2574 if (const CXXMethodDecl *MD = me->getMethodDecl()) 2575 Summ = Summaries.getSummary(MD); 2576 } 2577 2578 // If we didn't get a summary, this function doesn't affect retain counts. 2579 if (!Summ) 2580 return; 2581 2582 checkSummary(*Summ, CallOrObjCMessage(CE, state), C); 2583} 2584 2585void RetainCountChecker::checkPostStmt(const CXXConstructExpr *CE, 2586 CheckerContext &C) const { 2587 const CXXConstructorDecl *Ctor = CE->getConstructor(); 2588 if (!Ctor) 2589 return; 2590 2591 RetainSummaryManager &Summaries = getSummaryManager(C); 2592 RetainSummary *Summ = Summaries.getSummary(Ctor); 2593 2594 // If we didn't get a summary, this constructor doesn't affect retain counts. 2595 if (!Summ) 2596 return; 2597 2598 const ProgramState *state = C.getState(); 2599 checkSummary(*Summ, CallOrObjCMessage(CE, state), C); 2600} 2601 2602void RetainCountChecker::checkPostObjCMessage(const ObjCMessage &Msg, 2603 CheckerContext &C) const { 2604 const ProgramState *state = C.getState(); 2605 ExplodedNode *Pred = C.getPredecessor(); 2606 2607 RetainSummaryManager &Summaries = getSummaryManager(C); 2608 2609 RetainSummary *Summ; 2610 if (Msg.isInstanceMessage()) { 2611 const LocationContext *LC = Pred->getLocationContext(); 2612 Summ = Summaries.getInstanceMethodSummary(Msg, state, LC); 2613 } else { 2614 Summ = Summaries.getClassMethodSummary(Msg); 2615 } 2616 2617 // If we didn't get a summary, this message doesn't affect retain counts. 2618 if (!Summ) 2619 return; 2620 2621 checkSummary(*Summ, CallOrObjCMessage(Msg, state), C); 2622} 2623 2624/// GetReturnType - Used to get the return type of a message expression or 2625/// function call with the intention of affixing that type to a tracked symbol. 2626/// While the the return type can be queried directly from RetEx, when 2627/// invoking class methods we augment to the return type to be that of 2628/// a pointer to the class (as opposed it just being id). 2629// FIXME: We may be able to do this with related result types instead. 2630// This function is probably overestimating. 2631static QualType GetReturnType(const Expr *RetE, ASTContext &Ctx) { 2632 QualType RetTy = RetE->getType(); 2633 // If RetE is not a message expression just return its type. 2634 // If RetE is a message expression, return its types if it is something 2635 /// more specific than id. 2636 if (const ObjCMessageExpr *ME = dyn_cast<ObjCMessageExpr>(RetE)) 2637 if (const ObjCObjectPointerType *PT = RetTy->getAs<ObjCObjectPointerType>()) 2638 if (PT->isObjCQualifiedIdType() || PT->isObjCIdType() || 2639 PT->isObjCClassType()) { 2640 // At this point we know the return type of the message expression is 2641 // id, id<...>, or Class. If we have an ObjCInterfaceDecl, we know this 2642 // is a call to a class method whose type we can resolve. In such 2643 // cases, promote the return type to XXX* (where XXX is the class). 2644 const ObjCInterfaceDecl *D = ME->getReceiverInterface(); 2645 return !D ? RetTy : 2646 Ctx.getObjCObjectPointerType(Ctx.getObjCInterfaceType(D)); 2647 } 2648 2649 return RetTy; 2650} 2651 2652void RetainCountChecker::checkSummary(const RetainSummary &Summ, 2653 const CallOrObjCMessage &CallOrMsg, 2654 CheckerContext &C) const { 2655 const ProgramState *state = C.getState(); 2656 2657 // Evaluate the effect of the arguments. 2658 RefVal::Kind hasErr = (RefVal::Kind) 0; 2659 SourceRange ErrorRange; 2660 SymbolRef ErrorSym = 0; 2661 2662 for (unsigned idx = 0, e = CallOrMsg.getNumArgs(); idx != e; ++idx) { 2663 SVal V = CallOrMsg.getArgSVal(idx); 2664 2665 if (SymbolRef Sym = V.getAsLocSymbol()) { 2666 if (RefBindings::data_type *T = state->get<RefBindings>(Sym)) { 2667 state = updateSymbol(state, Sym, *T, Summ.getArg(idx), hasErr, C); 2668 if (hasErr) { 2669 ErrorRange = CallOrMsg.getArgSourceRange(idx); 2670 ErrorSym = Sym; 2671 break; 2672 } 2673 } 2674 } 2675 } 2676 2677 // Evaluate the effect on the message receiver. 2678 bool ReceiverIsTracked = false; 2679 if (!hasErr && CallOrMsg.isObjCMessage()) { 2680 const LocationContext *LC = C.getPredecessor()->getLocationContext(); 2681 SVal Receiver = CallOrMsg.getInstanceMessageReceiver(LC); 2682 if (SymbolRef Sym = Receiver.getAsLocSymbol()) { 2683 if (const RefVal *T = state->get<RefBindings>(Sym)) { 2684 ReceiverIsTracked = true; 2685 state = updateSymbol(state, Sym, *T, Summ.getReceiverEffect(), 2686 hasErr, C); 2687 if (hasErr) { 2688 ErrorRange = CallOrMsg.getReceiverSourceRange(); 2689 ErrorSym = Sym; 2690 } 2691 } 2692 } 2693 } 2694 2695 // Process any errors. 2696 if (hasErr) { 2697 processNonLeakError(state, ErrorRange, hasErr, ErrorSym, C); 2698 return; 2699 } 2700 2701 // Consult the summary for the return value. 2702 RetEffect RE = Summ.getRetEffect(); 2703 2704 if (RE.getKind() == RetEffect::OwnedWhenTrackedReceiver) { 2705 if (ReceiverIsTracked) 2706 RE = getSummaryManager(C).getObjAllocRetEffect(); 2707 else 2708 RE = RetEffect::MakeNoRet(); 2709 } 2710 2711 switch (RE.getKind()) { 2712 default: 2713 llvm_unreachable("Unhandled RetEffect."); break; 2714 2715 case RetEffect::NoRet: 2716 // No work necessary. 2717 break; 2718 2719 case RetEffect::OwnedAllocatedSymbol: 2720 case RetEffect::OwnedSymbol: { 2721 SymbolRef Sym = state->getSVal(CallOrMsg.getOriginExpr()).getAsSymbol(); 2722 if (!Sym) 2723 break; 2724 2725 // Use the result type from callOrMsg as it automatically adjusts 2726 // for methods/functions that return references. 2727 QualType ResultTy = CallOrMsg.getResultType(C.getASTContext()); 2728 state = state->set<RefBindings>(Sym, RefVal::makeOwned(RE.getObjKind(), 2729 ResultTy)); 2730 2731 // FIXME: Add a flag to the checker where allocations are assumed to 2732 // *not* fail. (The code below is out-of-date, though.) 2733#if 0 2734 if (RE.getKind() == RetEffect::OwnedAllocatedSymbol) { 2735 bool isFeasible; 2736 state = state.assume(loc::SymbolVal(Sym), true, isFeasible); 2737 assert(isFeasible && "Cannot assume fresh symbol is non-null."); 2738 } 2739#endif 2740 2741 break; 2742 } 2743 2744 case RetEffect::GCNotOwnedSymbol: 2745 case RetEffect::ARCNotOwnedSymbol: 2746 case RetEffect::NotOwnedSymbol: { 2747 const Expr *Ex = CallOrMsg.getOriginExpr(); 2748 SymbolRef Sym = state->getSVal(Ex).getAsSymbol(); 2749 if (!Sym) 2750 break; 2751 2752 // Use GetReturnType in order to give [NSFoo alloc] the type NSFoo *. 2753 QualType ResultTy = GetReturnType(Ex, C.getASTContext()); 2754 state = state->set<RefBindings>(Sym, RefVal::makeNotOwned(RE.getObjKind(), 2755 ResultTy)); 2756 break; 2757 } 2758 } 2759 2760 // This check is actually necessary; otherwise the statement builder thinks 2761 // we've hit a previously-found path. 2762 // Normally addTransition takes care of this, but we want the node pointer. 2763 ExplodedNode *NewNode; 2764 if (state == C.getState()) { 2765 NewNode = C.getPredecessor(); 2766 } else { 2767 NewNode = C.generateNode(state); 2768 } 2769 2770 // Annotate the node with summary we used. 2771 if (NewNode) { 2772 // FIXME: This is ugly. See checkEndAnalysis for why it's necessary. 2773 if (ShouldResetSummaryLog) { 2774 SummaryLog.clear(); 2775 ShouldResetSummaryLog = false; 2776 } 2777 SummaryLog[NewNode] = &Summ; 2778 } 2779} 2780 2781 2782const ProgramState * 2783RetainCountChecker::updateSymbol(const ProgramState *state, SymbolRef sym, 2784 RefVal V, ArgEffect E, RefVal::Kind &hasErr, 2785 CheckerContext &C) const { 2786 // In GC mode [... release] and [... retain] do nothing. 2787 // In ARC mode they shouldn't exist at all, but we just ignore them. 2788 bool IgnoreRetainMsg = C.isObjCGCEnabled(); 2789 if (!IgnoreRetainMsg) 2790 IgnoreRetainMsg = (bool)C.getASTContext().getLangOptions().ObjCAutoRefCount; 2791 2792 switch (E) { 2793 default: break; 2794 case IncRefMsg: E = IgnoreRetainMsg ? DoNothing : IncRef; break; 2795 case DecRefMsg: E = IgnoreRetainMsg ? DoNothing : DecRef; break; 2796 case MakeCollectable: E = C.isObjCGCEnabled() ? DecRef : DoNothing; break; 2797 case NewAutoreleasePool: E = C.isObjCGCEnabled() ? DoNothing : 2798 NewAutoreleasePool; break; 2799 } 2800 2801 // Handle all use-after-releases. 2802 if (!C.isObjCGCEnabled() && V.getKind() == RefVal::Released) { 2803 V = V ^ RefVal::ErrorUseAfterRelease; 2804 hasErr = V.getKind(); 2805 return state->set<RefBindings>(sym, V); 2806 } 2807 2808 switch (E) { 2809 case DecRefMsg: 2810 case IncRefMsg: 2811 case MakeCollectable: 2812 llvm_unreachable("DecRefMsg/IncRefMsg/MakeCollectable already converted"); 2813 return state; 2814 2815 case Dealloc: 2816 // Any use of -dealloc in GC is *bad*. 2817 if (C.isObjCGCEnabled()) { 2818 V = V ^ RefVal::ErrorDeallocGC; 2819 hasErr = V.getKind(); 2820 break; 2821 } 2822 2823 switch (V.getKind()) { 2824 default: 2825 llvm_unreachable("Invalid RefVal state for an explicit dealloc."); 2826 break; 2827 case RefVal::Owned: 2828 // The object immediately transitions to the released state. 2829 V = V ^ RefVal::Released; 2830 V.clearCounts(); 2831 return state->set<RefBindings>(sym, V); 2832 case RefVal::NotOwned: 2833 V = V ^ RefVal::ErrorDeallocNotOwned; 2834 hasErr = V.getKind(); 2835 break; 2836 } 2837 break; 2838 2839 case NewAutoreleasePool: 2840 assert(!C.isObjCGCEnabled()); 2841 return state->add<AutoreleaseStack>(sym); 2842 2843 case MayEscape: 2844 if (V.getKind() == RefVal::Owned) { 2845 V = V ^ RefVal::NotOwned; 2846 break; 2847 } 2848 2849 // Fall-through. 2850 2851 case DoNothing: 2852 return state; 2853 2854 case Autorelease: 2855 if (C.isObjCGCEnabled()) 2856 return state; 2857 2858 // Update the autorelease counts. 2859 state = SendAutorelease(state, ARCountFactory, sym); 2860 V = V.autorelease(); 2861 break; 2862 2863 case StopTracking: 2864 return state->remove<RefBindings>(sym); 2865 2866 case IncRef: 2867 switch (V.getKind()) { 2868 default: 2869 llvm_unreachable("Invalid RefVal state for a retain."); 2870 break; 2871 case RefVal::Owned: 2872 case RefVal::NotOwned: 2873 V = V + 1; 2874 break; 2875 case RefVal::Released: 2876 // Non-GC cases are handled above. 2877 assert(C.isObjCGCEnabled()); 2878 V = (V ^ RefVal::Owned) + 1; 2879 break; 2880 } 2881 break; 2882 2883 case SelfOwn: 2884 V = V ^ RefVal::NotOwned; 2885 // Fall-through. 2886 case DecRef: 2887 case DecRefBridgedTransfered: 2888 switch (V.getKind()) { 2889 default: 2890 // case 'RefVal::Released' handled above. 2891 llvm_unreachable("Invalid RefVal state for a release."); 2892 break; 2893 2894 case RefVal::Owned: 2895 assert(V.getCount() > 0); 2896 if (V.getCount() == 1) 2897 V = V ^ (E == DecRefBridgedTransfered ? 2898 RefVal::NotOwned : RefVal::Released); 2899 V = V - 1; 2900 break; 2901 2902 case RefVal::NotOwned: 2903 if (V.getCount() > 0) 2904 V = V - 1; 2905 else { 2906 V = V ^ RefVal::ErrorReleaseNotOwned; 2907 hasErr = V.getKind(); 2908 } 2909 break; 2910 2911 case RefVal::Released: 2912 // Non-GC cases are handled above. 2913 assert(C.isObjCGCEnabled()); 2914 V = V ^ RefVal::ErrorUseAfterRelease; 2915 hasErr = V.getKind(); 2916 break; 2917 } 2918 break; 2919 } 2920 return state->set<RefBindings>(sym, V); 2921} 2922 2923void RetainCountChecker::processNonLeakError(const ProgramState *St, 2924 SourceRange ErrorRange, 2925 RefVal::Kind ErrorKind, 2926 SymbolRef Sym, 2927 CheckerContext &C) const { 2928 ExplodedNode *N = C.generateSink(St); 2929 if (!N) 2930 return; 2931 2932 CFRefBug *BT; 2933 switch (ErrorKind) { 2934 default: 2935 llvm_unreachable("Unhandled error."); 2936 return; 2937 case RefVal::ErrorUseAfterRelease: 2938 if (!useAfterRelease) 2939 useAfterRelease.reset(new UseAfterRelease()); 2940 BT = &*useAfterRelease; 2941 break; 2942 case RefVal::ErrorReleaseNotOwned: 2943 if (!releaseNotOwned) 2944 releaseNotOwned.reset(new BadRelease()); 2945 BT = &*releaseNotOwned; 2946 break; 2947 case RefVal::ErrorDeallocGC: 2948 if (!deallocGC) 2949 deallocGC.reset(new DeallocGC()); 2950 BT = &*deallocGC; 2951 break; 2952 case RefVal::ErrorDeallocNotOwned: 2953 if (!deallocNotOwned) 2954 deallocNotOwned.reset(new DeallocNotOwned()); 2955 BT = &*deallocNotOwned; 2956 break; 2957 } 2958 2959 assert(BT); 2960 CFRefReport *report = new CFRefReport(*BT, C.getASTContext().getLangOptions(), 2961 C.isObjCGCEnabled(), SummaryLog, 2962 N, Sym); 2963 report->addRange(ErrorRange); 2964 C.EmitReport(report); 2965} 2966 2967//===----------------------------------------------------------------------===// 2968// Handle the return values of retain-count-related functions. 2969//===----------------------------------------------------------------------===// 2970 2971bool RetainCountChecker::evalCall(const CallExpr *CE, CheckerContext &C) const { 2972 // Get the callee. We're only interested in simple C functions. 2973 const ProgramState *state = C.getState(); 2974 const Expr *Callee = CE->getCallee(); 2975 SVal L = state->getSVal(Callee); 2976 2977 const FunctionDecl *FD = L.getAsFunctionDecl(); 2978 if (!FD) 2979 return false; 2980 2981 IdentifierInfo *II = FD->getIdentifier(); 2982 if (!II) 2983 return false; 2984 2985 // For now, we're only handling the functions that return aliases of their 2986 // arguments: CFRetain and CFMakeCollectable (and their families). 2987 // Eventually we should add other functions we can model entirely, 2988 // such as CFRelease, which don't invalidate their arguments or globals. 2989 if (CE->getNumArgs() != 1) 2990 return false; 2991 2992 // Get the name of the function. 2993 StringRef FName = II->getName(); 2994 FName = FName.substr(FName.find_first_not_of('_')); 2995 2996 // See if it's one of the specific functions we know how to eval. 2997 bool canEval = false; 2998 2999 QualType ResultTy = FD->getResultType(); 3000 if (ResultTy->isObjCIdType()) { 3001 // Handle: id NSMakeCollectable(CFTypeRef) 3002 canEval = II->isStr("NSMakeCollectable"); 3003 } else if (ResultTy->isPointerType()) { 3004 // Handle: (CF|CG)Retain 3005 // CFMakeCollectable 3006 // It's okay to be a little sloppy here (CGMakeCollectable doesn't exist). 3007 if (cocoa::isRefType(ResultTy, "CF", FName) || 3008 cocoa::isRefType(ResultTy, "CG", FName)) { 3009 canEval = isRetain(FD, FName) || isMakeCollectable(FD, FName); 3010 } 3011 } 3012 3013 if (!canEval) 3014 return false; 3015 3016 // Bind the return value. 3017 SVal RetVal = state->getSVal(CE->getArg(0)); 3018 if (RetVal.isUnknown()) { 3019 // If the receiver is unknown, conjure a return value. 3020 SValBuilder &SVB = C.getSValBuilder(); 3021 unsigned Count = C.getCurrentBlockCount(); 3022 SVal RetVal = SVB.getConjuredSymbolVal(0, CE, ResultTy, Count); 3023 } 3024 state = state->BindExpr(CE, RetVal, false); 3025 3026 // FIXME: This should not be necessary, but otherwise the argument seems to be 3027 // considered alive during the next statement. 3028 if (const MemRegion *ArgRegion = RetVal.getAsRegion()) { 3029 // Save the refcount status of the argument. 3030 SymbolRef Sym = RetVal.getAsLocSymbol(); 3031 RefBindings::data_type *Binding = 0; 3032 if (Sym) 3033 Binding = state->get<RefBindings>(Sym); 3034 3035 // Invalidate the argument region. 3036 unsigned Count = C.getCurrentBlockCount(); 3037 state = state->invalidateRegions(ArgRegion, CE, Count); 3038 3039 // Restore the refcount status of the argument. 3040 if (Binding) 3041 state = state->set<RefBindings>(Sym, *Binding); 3042 } 3043 3044 C.addTransition(state); 3045 return true; 3046} 3047 3048//===----------------------------------------------------------------------===// 3049// Handle return statements. 3050//===----------------------------------------------------------------------===// 3051 3052void RetainCountChecker::checkPreStmt(const ReturnStmt *S, 3053 CheckerContext &C) const { 3054 const Expr *RetE = S->getRetValue(); 3055 if (!RetE) 3056 return; 3057 3058 const ProgramState *state = C.getState(); 3059 SymbolRef Sym = state->getSValAsScalarOrLoc(RetE).getAsLocSymbol(); 3060 if (!Sym) 3061 return; 3062 3063 // Get the reference count binding (if any). 3064 const RefVal *T = state->get<RefBindings>(Sym); 3065 if (!T) 3066 return; 3067 3068 // Change the reference count. 3069 RefVal X = *T; 3070 3071 switch (X.getKind()) { 3072 case RefVal::Owned: { 3073 unsigned cnt = X.getCount(); 3074 assert(cnt > 0); 3075 X.setCount(cnt - 1); 3076 X = X ^ RefVal::ReturnedOwned; 3077 break; 3078 } 3079 3080 case RefVal::NotOwned: { 3081 unsigned cnt = X.getCount(); 3082 if (cnt) { 3083 X.setCount(cnt - 1); 3084 X = X ^ RefVal::ReturnedOwned; 3085 } 3086 else { 3087 X = X ^ RefVal::ReturnedNotOwned; 3088 } 3089 break; 3090 } 3091 3092 default: 3093 return; 3094 } 3095 3096 // Update the binding. 3097 state = state->set<RefBindings>(Sym, X); 3098 ExplodedNode *Pred = C.generateNode(state); 3099 3100 // At this point we have updated the state properly. 3101 // Everything after this is merely checking to see if the return value has 3102 // been over- or under-retained. 3103 3104 // Did we cache out? 3105 if (!Pred) 3106 return; 3107 3108 // Update the autorelease counts. 3109 static SimpleProgramPointTag 3110 AutoreleaseTag("RetainCountChecker : Autorelease"); 3111 GenericNodeBuilderRefCount Bd(C, &AutoreleaseTag); 3112 llvm::tie(Pred, state) = handleAutoreleaseCounts(state, Bd, Pred, 3113 C.getEngine(), Sym, X); 3114 3115 // Did we cache out? 3116 if (!Pred) 3117 return; 3118 3119 // Get the updated binding. 3120 T = state->get<RefBindings>(Sym); 3121 assert(T); 3122 X = *T; 3123 3124 // Consult the summary of the enclosing method. 3125 RetainSummaryManager &Summaries = getSummaryManager(C); 3126 const Decl *CD = &Pred->getCodeDecl(); 3127 3128 if (const ObjCMethodDecl *MD = dyn_cast<ObjCMethodDecl>(CD)) { 3129 // Unlike regular functions, /all/ ObjC methods are assumed to always 3130 // follow Cocoa retain-count conventions, not just those with special 3131 // names or attributes. 3132 const RetainSummary *Summ = Summaries.getMethodSummary(MD); 3133 RetEffect RE = Summ ? Summ->getRetEffect() : RetEffect::MakeNoRet(); 3134 checkReturnWithRetEffect(S, C, Pred, RE, X, Sym, state); 3135 } 3136 3137 if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(CD)) { 3138 if (!isa<CXXMethodDecl>(FD)) 3139 if (const RetainSummary *Summ = Summaries.getSummary(FD)) 3140 checkReturnWithRetEffect(S, C, Pred, Summ->getRetEffect(), X, 3141 Sym, state); 3142 } 3143} 3144 3145void RetainCountChecker::checkReturnWithRetEffect(const ReturnStmt *S, 3146 CheckerContext &C, 3147 ExplodedNode *Pred, 3148 RetEffect RE, RefVal X, 3149 SymbolRef Sym, 3150 const ProgramState *state) const { 3151 // Any leaks or other errors? 3152 if (X.isReturnedOwned() && X.getCount() == 0) { 3153 if (RE.getKind() != RetEffect::NoRet) { 3154 bool hasError = false; 3155 if (C.isObjCGCEnabled() && RE.getObjKind() == RetEffect::ObjC) { 3156 // Things are more complicated with garbage collection. If the 3157 // returned object is suppose to be an Objective-C object, we have 3158 // a leak (as the caller expects a GC'ed object) because no 3159 // method should return ownership unless it returns a CF object. 3160 hasError = true; 3161 X = X ^ RefVal::ErrorGCLeakReturned; 3162 } 3163 else if (!RE.isOwned()) { 3164 // Either we are using GC and the returned object is a CF type 3165 // or we aren't using GC. In either case, we expect that the 3166 // enclosing method is expected to return ownership. 3167 hasError = true; 3168 X = X ^ RefVal::ErrorLeakReturned; 3169 } 3170 3171 if (hasError) { 3172 // Generate an error node. 3173 state = state->set<RefBindings>(Sym, X); 3174 3175 static SimpleProgramPointTag 3176 ReturnOwnLeakTag("RetainCountChecker : ReturnsOwnLeak"); 3177 ExplodedNode *N = C.generateNode(state, Pred, &ReturnOwnLeakTag); 3178 if (N) { 3179 const LangOptions &LOpts = C.getASTContext().getLangOptions(); 3180 bool GCEnabled = C.isObjCGCEnabled(); 3181 CFRefReport *report = 3182 new CFRefLeakReport(*getLeakAtReturnBug(LOpts, GCEnabled), 3183 LOpts, GCEnabled, SummaryLog, 3184 N, Sym, C.getEngine()); 3185 C.EmitReport(report); 3186 } 3187 } 3188 } 3189 } else if (X.isReturnedNotOwned()) { 3190 if (RE.isOwned()) { 3191 // Trying to return a not owned object to a caller expecting an 3192 // owned object. 3193 state = state->set<RefBindings>(Sym, X ^ RefVal::ErrorReturnedNotOwned); 3194 3195 static SimpleProgramPointTag 3196 ReturnNotOwnedTag("RetainCountChecker : ReturnNotOwnedForOwned"); 3197 ExplodedNode *N = C.generateNode(state, Pred, &ReturnNotOwnedTag); 3198 if (N) { 3199 if (!returnNotOwnedForOwned) 3200 returnNotOwnedForOwned.reset(new ReturnedNotOwnedForOwned()); 3201 3202 CFRefReport *report = 3203 new CFRefReport(*returnNotOwnedForOwned, 3204 C.getASTContext().getLangOptions(), 3205 C.isObjCGCEnabled(), SummaryLog, N, Sym); 3206 C.EmitReport(report); 3207 } 3208 } 3209 } 3210} 3211 3212//===----------------------------------------------------------------------===// 3213// Check various ways a symbol can be invalidated. 3214//===----------------------------------------------------------------------===// 3215 3216void RetainCountChecker::checkBind(SVal loc, SVal val, 3217 CheckerContext &C) const { 3218 // Are we storing to something that causes the value to "escape"? 3219 bool escapes = true; 3220 3221 // A value escapes in three possible cases (this may change): 3222 // 3223 // (1) we are binding to something that is not a memory region. 3224 // (2) we are binding to a memregion that does not have stack storage 3225 // (3) we are binding to a memregion with stack storage that the store 3226 // does not understand. 3227 const ProgramState *state = C.getState(); 3228 3229 if (loc::MemRegionVal *regionLoc = dyn_cast<loc::MemRegionVal>(&loc)) { 3230 escapes = !regionLoc->getRegion()->hasStackStorage(); 3231 3232 if (!escapes) { 3233 // To test (3), generate a new state with the binding added. If it is 3234 // the same state, then it escapes (since the store cannot represent 3235 // the binding). 3236 escapes = (state == (state->bindLoc(*regionLoc, val))); 3237 } 3238 } 3239 3240 // If our store can represent the binding and we aren't storing to something 3241 // that doesn't have local storage then just return and have the simulation 3242 // state continue as is. 3243 if (!escapes) 3244 return; 3245 3246 // Otherwise, find all symbols referenced by 'val' that we are tracking 3247 // and stop tracking them. 3248 state = state->scanReachableSymbols<StopTrackingCallback>(val).getState(); 3249 C.addTransition(state); 3250} 3251 3252const ProgramState *RetainCountChecker::evalAssume(const ProgramState *state, 3253 SVal Cond, 3254 bool Assumption) const { 3255 3256 // FIXME: We may add to the interface of evalAssume the list of symbols 3257 // whose assumptions have changed. For now we just iterate through the 3258 // bindings and check if any of the tracked symbols are NULL. This isn't 3259 // too bad since the number of symbols we will track in practice are 3260 // probably small and evalAssume is only called at branches and a few 3261 // other places. 3262 RefBindings B = state->get<RefBindings>(); 3263 3264 if (B.isEmpty()) 3265 return state; 3266 3267 bool changed = false; 3268 RefBindings::Factory &RefBFactory = state->get_context<RefBindings>(); 3269 3270 for (RefBindings::iterator I = B.begin(), E = B.end(); I != E; ++I) { 3271 // Check if the symbol is null (or equal to any constant). 3272 // If this is the case, stop tracking the symbol. 3273 if (state->getSymVal(I.getKey())) { 3274 changed = true; 3275 B = RefBFactory.remove(B, I.getKey()); 3276 } 3277 } 3278 3279 if (changed) 3280 state = state->set<RefBindings>(B); 3281 3282 return state; 3283} 3284 3285const ProgramState * 3286RetainCountChecker::checkRegionChanges(const ProgramState *state, 3287 const StoreManager::InvalidatedSymbols *invalidated, 3288 ArrayRef<const MemRegion *> ExplicitRegions, 3289 ArrayRef<const MemRegion *> Regions) const { 3290 if (!invalidated) 3291 return state; 3292 3293 llvm::SmallPtrSet<SymbolRef, 8> WhitelistedSymbols; 3294 for (ArrayRef<const MemRegion *>::iterator I = ExplicitRegions.begin(), 3295 E = ExplicitRegions.end(); I != E; ++I) { 3296 if (const SymbolicRegion *SR = (*I)->StripCasts()->getAs<SymbolicRegion>()) 3297 WhitelistedSymbols.insert(SR->getSymbol()); 3298 } 3299 3300 for (StoreManager::InvalidatedSymbols::const_iterator I=invalidated->begin(), 3301 E = invalidated->end(); I!=E; ++I) { 3302 SymbolRef sym = *I; 3303 if (WhitelistedSymbols.count(sym)) 3304 continue; 3305 // Remove any existing reference-count binding. 3306 state = state->remove<RefBindings>(sym); 3307 } 3308 return state; 3309} 3310 3311//===----------------------------------------------------------------------===// 3312// Handle dead symbols and end-of-path. 3313//===----------------------------------------------------------------------===// 3314 3315std::pair<ExplodedNode *, const ProgramState *> 3316RetainCountChecker::handleAutoreleaseCounts(const ProgramState *state, 3317 GenericNodeBuilderRefCount Bd, 3318 ExplodedNode *Pred, ExprEngine &Eng, 3319 SymbolRef Sym, RefVal V) const { 3320 unsigned ACnt = V.getAutoreleaseCount(); 3321 3322 // No autorelease counts? Nothing to be done. 3323 if (!ACnt) 3324 return std::make_pair(Pred, state); 3325 3326 assert(!Eng.isObjCGCEnabled() && "Autorelease counts in GC mode?"); 3327 unsigned Cnt = V.getCount(); 3328 3329 // FIXME: Handle sending 'autorelease' to already released object. 3330 3331 if (V.getKind() == RefVal::ReturnedOwned) 3332 ++Cnt; 3333 3334 if (ACnt <= Cnt) { 3335 if (ACnt == Cnt) { 3336 V.clearCounts(); 3337 if (V.getKind() == RefVal::ReturnedOwned) 3338 V = V ^ RefVal::ReturnedNotOwned; 3339 else 3340 V = V ^ RefVal::NotOwned; 3341 } else { 3342 V.setCount(Cnt - ACnt); 3343 V.setAutoreleaseCount(0); 3344 } 3345 state = state->set<RefBindings>(Sym, V); 3346 ExplodedNode *N = Bd.MakeNode(state, Pred); 3347 if (N == 0) 3348 state = 0; 3349 return std::make_pair(N, state); 3350 } 3351 3352 // Woah! More autorelease counts then retain counts left. 3353 // Emit hard error. 3354 V = V ^ RefVal::ErrorOverAutorelease; 3355 state = state->set<RefBindings>(Sym, V); 3356 3357 if (ExplodedNode *N = Bd.MakeNode(state, Pred)) { 3358 N->markAsSink(); 3359 3360 llvm::SmallString<128> sbuf; 3361 llvm::raw_svector_ostream os(sbuf); 3362 os << "Object over-autoreleased: object was sent -autorelease "; 3363 if (V.getAutoreleaseCount() > 1) 3364 os << V.getAutoreleaseCount() << " times "; 3365 os << "but the object has a +" << V.getCount() << " retain count"; 3366 3367 if (!overAutorelease) 3368 overAutorelease.reset(new OverAutorelease()); 3369 3370 const LangOptions &LOpts = Eng.getContext().getLangOptions(); 3371 CFRefReport *report = 3372 new CFRefReport(*overAutorelease, LOpts, /* GCEnabled = */ false, 3373 SummaryLog, N, Sym, os.str()); 3374 Eng.getBugReporter().EmitReport(report); 3375 } 3376 3377 return std::make_pair((ExplodedNode *)0, (const ProgramState *)0); 3378} 3379 3380const ProgramState * 3381RetainCountChecker::handleSymbolDeath(const ProgramState *state, 3382 SymbolRef sid, RefVal V, 3383 SmallVectorImpl<SymbolRef> &Leaked) const { 3384 bool hasLeak = false; 3385 if (V.isOwned()) 3386 hasLeak = true; 3387 else if (V.isNotOwned() || V.isReturnedOwned()) 3388 hasLeak = (V.getCount() > 0); 3389 3390 if (!hasLeak) 3391 return state->remove<RefBindings>(sid); 3392 3393 Leaked.push_back(sid); 3394 return state->set<RefBindings>(sid, V ^ RefVal::ErrorLeak); 3395} 3396 3397ExplodedNode * 3398RetainCountChecker::processLeaks(const ProgramState *state, 3399 SmallVectorImpl<SymbolRef> &Leaked, 3400 GenericNodeBuilderRefCount &Builder, 3401 ExprEngine &Eng, ExplodedNode *Pred) const { 3402 if (Leaked.empty()) 3403 return Pred; 3404 3405 // Generate an intermediate node representing the leak point. 3406 ExplodedNode *N = Builder.MakeNode(state, Pred); 3407 3408 if (N) { 3409 for (SmallVectorImpl<SymbolRef>::iterator 3410 I = Leaked.begin(), E = Leaked.end(); I != E; ++I) { 3411 3412 const LangOptions &LOpts = Eng.getContext().getLangOptions(); 3413 bool GCEnabled = Eng.isObjCGCEnabled(); 3414 CFRefBug *BT = Pred ? getLeakWithinFunctionBug(LOpts, GCEnabled) 3415 : getLeakAtReturnBug(LOpts, GCEnabled); 3416 assert(BT && "BugType not initialized."); 3417 3418 CFRefLeakReport *report = new CFRefLeakReport(*BT, LOpts, GCEnabled, 3419 SummaryLog, N, *I, Eng); 3420 Eng.getBugReporter().EmitReport(report); 3421 } 3422 } 3423 3424 return N; 3425} 3426 3427void RetainCountChecker::checkEndPath(EndOfFunctionNodeBuilder &Builder, 3428 ExprEngine &Eng) const { 3429 const ProgramState *state = Builder.getState(); 3430 GenericNodeBuilderRefCount Bd(Builder); 3431 RefBindings B = state->get<RefBindings>(); 3432 ExplodedNode *Pred = Builder.getPredecessor(); 3433 3434 for (RefBindings::iterator I = B.begin(), E = B.end(); I != E; ++I) { 3435 llvm::tie(Pred, state) = handleAutoreleaseCounts(state, Bd, Pred, Eng, 3436 I->first, I->second); 3437 if (!state) 3438 return; 3439 } 3440 3441 B = state->get<RefBindings>(); 3442 SmallVector<SymbolRef, 10> Leaked; 3443 3444 for (RefBindings::iterator I = B.begin(), E = B.end(); I != E; ++I) 3445 state = handleSymbolDeath(state, I->first, I->second, Leaked); 3446 3447 processLeaks(state, Leaked, Bd, Eng, Pred); 3448} 3449 3450const ProgramPointTag * 3451RetainCountChecker::getDeadSymbolTag(SymbolRef sym) const { 3452 const SimpleProgramPointTag *&tag = DeadSymbolTags[sym]; 3453 if (!tag) { 3454 llvm::SmallString<64> buf; 3455 llvm::raw_svector_ostream out(buf); 3456 out << "RetainCountChecker : Dead Symbol : " << sym->getSymbolID(); 3457 tag = new SimpleProgramPointTag(out.str()); 3458 } 3459 return tag; 3460} 3461 3462void RetainCountChecker::checkDeadSymbols(SymbolReaper &SymReaper, 3463 CheckerContext &C) const { 3464 ExprEngine &Eng = C.getEngine(); 3465 ExplodedNode *Pred = C.getPredecessor(); 3466 3467 const ProgramState *state = C.getState(); 3468 RefBindings B = state->get<RefBindings>(); 3469 3470 // Update counts from autorelease pools 3471 for (SymbolReaper::dead_iterator I = SymReaper.dead_begin(), 3472 E = SymReaper.dead_end(); I != E; ++I) { 3473 SymbolRef Sym = *I; 3474 if (const RefVal *T = B.lookup(Sym)){ 3475 // Use the symbol as the tag. 3476 // FIXME: This might not be as unique as we would like. 3477 GenericNodeBuilderRefCount Bd(C, getDeadSymbolTag(Sym)); 3478 llvm::tie(Pred, state) = handleAutoreleaseCounts(state, Bd, Pred, Eng, 3479 Sym, *T); 3480 if (!state) 3481 return; 3482 } 3483 } 3484 3485 B = state->get<RefBindings>(); 3486 SmallVector<SymbolRef, 10> Leaked; 3487 3488 for (SymbolReaper::dead_iterator I = SymReaper.dead_begin(), 3489 E = SymReaper.dead_end(); I != E; ++I) { 3490 if (const RefVal *T = B.lookup(*I)) 3491 state = handleSymbolDeath(state, *I, *T, Leaked); 3492 } 3493 3494 { 3495 GenericNodeBuilderRefCount Bd(C, this); 3496 Pred = processLeaks(state, Leaked, Bd, Eng, Pred); 3497 } 3498 3499 // Did we cache out? 3500 if (!Pred) 3501 return; 3502 3503 // Now generate a new node that nukes the old bindings. 3504 RefBindings::Factory &F = state->get_context<RefBindings>(); 3505 3506 for (SymbolReaper::dead_iterator I = SymReaper.dead_begin(), 3507 E = SymReaper.dead_end(); I != E; ++I) 3508 B = F.remove(B, *I); 3509 3510 state = state->set<RefBindings>(B); 3511 C.generateNode(state, Pred); 3512} 3513 3514//===----------------------------------------------------------------------===// 3515// Debug printing of refcount bindings and autorelease pools. 3516//===----------------------------------------------------------------------===// 3517 3518static void PrintPool(raw_ostream &Out, SymbolRef Sym, 3519 const ProgramState *State) { 3520 Out << ' '; 3521 if (Sym) 3522 Out << Sym->getSymbolID(); 3523 else 3524 Out << "<pool>"; 3525 Out << ":{"; 3526 3527 // Get the contents of the pool. 3528 if (const ARCounts *Cnts = State->get<AutoreleasePoolContents>(Sym)) 3529 for (ARCounts::iterator I = Cnts->begin(), E = Cnts->end(); I != E; ++I) 3530 Out << '(' << I.getKey() << ',' << I.getData() << ')'; 3531 3532 Out << '}'; 3533} 3534 3535static bool UsesAutorelease(const ProgramState *state) { 3536 // A state uses autorelease if it allocated an autorelease pool or if it has 3537 // objects in the caller's autorelease pool. 3538 return !state->get<AutoreleaseStack>().isEmpty() || 3539 state->get<AutoreleasePoolContents>(SymbolRef()); 3540} 3541 3542void RetainCountChecker::printState(raw_ostream &Out, const ProgramState *State, 3543 const char *NL, const char *Sep) const { 3544 3545 RefBindings B = State->get<RefBindings>(); 3546 3547 if (!B.isEmpty()) 3548 Out << Sep << NL; 3549 3550 for (RefBindings::iterator I = B.begin(), E = B.end(); I != E; ++I) { 3551 Out << I->first << " : "; 3552 I->second.print(Out); 3553 Out << NL; 3554 } 3555 3556 // Print the autorelease stack. 3557 if (UsesAutorelease(State)) { 3558 Out << Sep << NL << "AR pool stack:"; 3559 ARStack Stack = State->get<AutoreleaseStack>(); 3560 3561 PrintPool(Out, SymbolRef(), State); // Print the caller's pool. 3562 for (ARStack::iterator I = Stack.begin(), E = Stack.end(); I != E; ++I) 3563 PrintPool(Out, *I, State); 3564 3565 Out << NL; 3566 } 3567} 3568 3569//===----------------------------------------------------------------------===// 3570// Checker registration. 3571//===----------------------------------------------------------------------===// 3572 3573void ento::registerRetainCountChecker(CheckerManager &Mgr) { 3574 Mgr.registerChecker<RetainCountChecker>(); 3575} 3576 3577