RetainCountChecker.cpp revision d1e5a89226da79f7e6f43d40facc46abda9e5245
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 StmtNodeBuilder *SNB; 47 const Stmt *S; 48 const ProgramPointTag *tag; 49 EndOfFunctionNodeBuilder *ENB; 50public: 51 GenericNodeBuilderRefCount(StmtNodeBuilder &snb, const Stmt *s, 52 const ProgramPointTag *t) 53 : SNB(&snb), S(s), tag(t), ENB(0) {} 54 55 GenericNodeBuilderRefCount(EndOfFunctionNodeBuilder &enb) 56 : SNB(0), S(0), tag(0), ENB(&enb) {} 57 58 ExplodedNode *MakeNode(const ProgramState *state, ExplodedNode *Pred) { 59 if (SNB) 60 return SNB->generateNode(PostStmt(S, Pred->getLocationContext(), tag), 61 state, Pred); 62 63 assert(ENB); 64 return ENB->generateNode(state, Pred); 65 } 66}; 67} // end anonymous namespace 68 69//===----------------------------------------------------------------------===// 70// Primitives used for constructing summaries for function/method calls. 71//===----------------------------------------------------------------------===// 72 73/// ArgEffect is used to summarize a function/method call's effect on a 74/// particular argument. 75enum ArgEffect { DoNothing, Autorelease, Dealloc, DecRef, DecRefMsg, 76 DecRefBridgedTransfered, 77 IncRefMsg, IncRef, MakeCollectable, MayEscape, 78 NewAutoreleasePool, SelfOwn, StopTracking }; 79 80namespace llvm { 81template <> struct FoldingSetTrait<ArgEffect> { 82static inline void Profile(const ArgEffect X, FoldingSetNodeID& ID) { 83 ID.AddInteger((unsigned) X); 84} 85}; 86} // end llvm namespace 87 88/// ArgEffects summarizes the effects of a function/method call on all of 89/// its arguments. 90typedef llvm::ImmutableMap<unsigned,ArgEffect> ArgEffects; 91 92namespace { 93 94/// RetEffect is used to summarize a function/method call's behavior with 95/// respect to its return value. 96class RetEffect { 97public: 98 enum Kind { NoRet, OwnedSymbol, OwnedAllocatedSymbol, 99 NotOwnedSymbol, GCNotOwnedSymbol, ARCNotOwnedSymbol, 100 OwnedWhenTrackedReceiver }; 101 102 enum ObjKind { CF, ObjC, AnyObj }; 103 104private: 105 Kind K; 106 ObjKind O; 107 108 RetEffect(Kind k, ObjKind o = AnyObj) : K(k), O(o) {} 109 110public: 111 Kind getKind() const { return K; } 112 113 ObjKind getObjKind() const { return O; } 114 115 bool isOwned() const { 116 return K == OwnedSymbol || K == OwnedAllocatedSymbol || 117 K == OwnedWhenTrackedReceiver; 118 } 119 120 bool operator==(const RetEffect &Other) const { 121 return K == Other.K && O == Other.O; 122 } 123 124 static RetEffect MakeOwnedWhenTrackedReceiver() { 125 return RetEffect(OwnedWhenTrackedReceiver, ObjC); 126 } 127 128 static RetEffect MakeOwned(ObjKind o, bool isAllocated = false) { 129 return RetEffect(isAllocated ? OwnedAllocatedSymbol : OwnedSymbol, o); 130 } 131 static RetEffect MakeNotOwned(ObjKind o) { 132 return RetEffect(NotOwnedSymbol, o); 133 } 134 static RetEffect MakeGCNotOwned() { 135 return RetEffect(GCNotOwnedSymbol, ObjC); 136 } 137 static RetEffect MakeARCNotOwned() { 138 return RetEffect(ARCNotOwnedSymbol, ObjC); 139 } 140 static RetEffect MakeNoRet() { 141 return RetEffect(NoRet); 142 } 143}; 144 145//===----------------------------------------------------------------------===// 146// Reference-counting logic (typestate + counts). 147//===----------------------------------------------------------------------===// 148 149class RefVal { 150public: 151 enum Kind { 152 Owned = 0, // Owning reference. 153 NotOwned, // Reference is not owned by still valid (not freed). 154 Released, // Object has been released. 155 ReturnedOwned, // Returned object passes ownership to caller. 156 ReturnedNotOwned, // Return object does not pass ownership to caller. 157 ERROR_START, 158 ErrorDeallocNotOwned, // -dealloc called on non-owned object. 159 ErrorDeallocGC, // Calling -dealloc with GC enabled. 160 ErrorUseAfterRelease, // Object used after released. 161 ErrorReleaseNotOwned, // Release of an object that was not owned. 162 ERROR_LEAK_START, 163 ErrorLeak, // A memory leak due to excessive reference counts. 164 ErrorLeakReturned, // A memory leak due to the returning method not having 165 // the correct naming conventions. 166 ErrorGCLeakReturned, 167 ErrorOverAutorelease, 168 ErrorReturnedNotOwned 169 }; 170 171private: 172 Kind kind; 173 RetEffect::ObjKind okind; 174 unsigned Cnt; 175 unsigned ACnt; 176 QualType T; 177 178 RefVal(Kind k, RetEffect::ObjKind o, unsigned cnt, unsigned acnt, QualType t) 179 : kind(k), okind(o), Cnt(cnt), ACnt(acnt), T(t) {} 180 181public: 182 Kind getKind() const { return kind; } 183 184 RetEffect::ObjKind getObjKind() const { return okind; } 185 186 unsigned getCount() const { return Cnt; } 187 unsigned getAutoreleaseCount() const { return ACnt; } 188 unsigned getCombinedCounts() const { return Cnt + ACnt; } 189 void clearCounts() { Cnt = 0; ACnt = 0; } 190 void setCount(unsigned i) { Cnt = i; } 191 void setAutoreleaseCount(unsigned i) { ACnt = i; } 192 193 QualType getType() const { return T; } 194 195 bool isOwned() const { 196 return getKind() == Owned; 197 } 198 199 bool isNotOwned() const { 200 return getKind() == NotOwned; 201 } 202 203 bool isReturnedOwned() const { 204 return getKind() == ReturnedOwned; 205 } 206 207 bool isReturnedNotOwned() const { 208 return getKind() == ReturnedNotOwned; 209 } 210 211 static RefVal makeOwned(RetEffect::ObjKind o, QualType t, 212 unsigned Count = 1) { 213 return RefVal(Owned, o, Count, 0, t); 214 } 215 216 static RefVal makeNotOwned(RetEffect::ObjKind o, QualType t, 217 unsigned Count = 0) { 218 return RefVal(NotOwned, o, Count, 0, t); 219 } 220 221 // Comparison, profiling, and pretty-printing. 222 223 bool operator==(const RefVal& X) const { 224 return kind == X.kind && Cnt == X.Cnt && T == X.T && ACnt == X.ACnt; 225 } 226 227 RefVal operator-(size_t i) const { 228 return RefVal(getKind(), getObjKind(), getCount() - i, 229 getAutoreleaseCount(), getType()); 230 } 231 232 RefVal operator+(size_t i) const { 233 return RefVal(getKind(), getObjKind(), getCount() + i, 234 getAutoreleaseCount(), getType()); 235 } 236 237 RefVal operator^(Kind k) const { 238 return RefVal(k, getObjKind(), getCount(), getAutoreleaseCount(), 239 getType()); 240 } 241 242 RefVal autorelease() const { 243 return RefVal(getKind(), getObjKind(), getCount(), getAutoreleaseCount()+1, 244 getType()); 245 } 246 247 void Profile(llvm::FoldingSetNodeID& ID) const { 248 ID.AddInteger((unsigned) kind); 249 ID.AddInteger(Cnt); 250 ID.AddInteger(ACnt); 251 ID.Add(T); 252 } 253 254 void print(raw_ostream &Out) const; 255}; 256 257void RefVal::print(raw_ostream &Out) const { 258 if (!T.isNull()) 259 Out << "Tracked " << T.getAsString() << '/'; 260 261 switch (getKind()) { 262 default: llvm_unreachable("Invalid RefVal kind"); 263 case Owned: { 264 Out << "Owned"; 265 unsigned cnt = getCount(); 266 if (cnt) Out << " (+ " << cnt << ")"; 267 break; 268 } 269 270 case NotOwned: { 271 Out << "NotOwned"; 272 unsigned cnt = getCount(); 273 if (cnt) Out << " (+ " << cnt << ")"; 274 break; 275 } 276 277 case ReturnedOwned: { 278 Out << "ReturnedOwned"; 279 unsigned cnt = getCount(); 280 if (cnt) Out << " (+ " << cnt << ")"; 281 break; 282 } 283 284 case ReturnedNotOwned: { 285 Out << "ReturnedNotOwned"; 286 unsigned cnt = getCount(); 287 if (cnt) Out << " (+ " << cnt << ")"; 288 break; 289 } 290 291 case Released: 292 Out << "Released"; 293 break; 294 295 case ErrorDeallocGC: 296 Out << "-dealloc (GC)"; 297 break; 298 299 case ErrorDeallocNotOwned: 300 Out << "-dealloc (not-owned)"; 301 break; 302 303 case ErrorLeak: 304 Out << "Leaked"; 305 break; 306 307 case ErrorLeakReturned: 308 Out << "Leaked (Bad naming)"; 309 break; 310 311 case ErrorGCLeakReturned: 312 Out << "Leaked (GC-ed at return)"; 313 break; 314 315 case ErrorUseAfterRelease: 316 Out << "Use-After-Release [ERROR]"; 317 break; 318 319 case ErrorReleaseNotOwned: 320 Out << "Release of Not-Owned [ERROR]"; 321 break; 322 323 case RefVal::ErrorOverAutorelease: 324 Out << "Over autoreleased"; 325 break; 326 327 case RefVal::ErrorReturnedNotOwned: 328 Out << "Non-owned object returned instead of owned"; 329 break; 330 } 331 332 if (ACnt) { 333 Out << " [ARC +" << ACnt << ']'; 334 } 335} 336} //end anonymous namespace 337 338//===----------------------------------------------------------------------===// 339// RefBindings - State used to track object reference counts. 340//===----------------------------------------------------------------------===// 341 342typedef llvm::ImmutableMap<SymbolRef, RefVal> RefBindings; 343 344namespace clang { 345namespace ento { 346template<> 347struct ProgramStateTrait<RefBindings> 348 : public ProgramStatePartialTrait<RefBindings> { 349 static void *GDMIndex() { 350 static int RefBIndex = 0; 351 return &RefBIndex; 352 } 353}; 354} 355} 356 357//===----------------------------------------------------------------------===// 358// Function/Method behavior summaries. 359//===----------------------------------------------------------------------===// 360 361namespace { 362class RetainSummary { 363 /// Args - an ordered vector of (index, ArgEffect) pairs, where index 364 /// specifies the argument (starting from 0). This can be sparsely 365 /// populated; arguments with no entry in Args use 'DefaultArgEffect'. 366 ArgEffects Args; 367 368 /// DefaultArgEffect - The default ArgEffect to apply to arguments that 369 /// do not have an entry in Args. 370 ArgEffect DefaultArgEffect; 371 372 /// Receiver - If this summary applies to an Objective-C message expression, 373 /// this is the effect applied to the state of the receiver. 374 ArgEffect Receiver; 375 376 /// Ret - The effect on the return value. Used to indicate if the 377 /// function/method call returns a new tracked symbol. 378 RetEffect Ret; 379 380public: 381 RetainSummary(ArgEffects A, RetEffect R, ArgEffect defaultEff, 382 ArgEffect ReceiverEff) 383 : Args(A), DefaultArgEffect(defaultEff), Receiver(ReceiverEff), Ret(R) {} 384 385 /// getArg - Return the argument effect on the argument specified by 386 /// idx (starting from 0). 387 ArgEffect getArg(unsigned idx) const { 388 if (const ArgEffect *AE = Args.lookup(idx)) 389 return *AE; 390 391 return DefaultArgEffect; 392 } 393 394 void addArg(ArgEffects::Factory &af, unsigned idx, ArgEffect e) { 395 Args = af.add(Args, idx, e); 396 } 397 398 /// setDefaultArgEffect - Set the default argument effect. 399 void setDefaultArgEffect(ArgEffect E) { 400 DefaultArgEffect = E; 401 } 402 403 /// getRetEffect - Returns the effect on the return value of the call. 404 RetEffect getRetEffect() const { return Ret; } 405 406 /// setRetEffect - Set the effect of the return value of the call. 407 void setRetEffect(RetEffect E) { Ret = E; } 408 409 410 /// Sets the effect on the receiver of the message. 411 void setReceiverEffect(ArgEffect e) { Receiver = e; } 412 413 /// getReceiverEffect - Returns the effect on the receiver of the call. 414 /// This is only meaningful if the summary applies to an ObjCMessageExpr*. 415 ArgEffect getReceiverEffect() const { return Receiver; } 416 417 /// Test if two retain summaries are identical. Note that merely equivalent 418 /// summaries are not necessarily identical (for example, if an explicit 419 /// argument effect matches the default effect). 420 bool operator==(const RetainSummary &Other) const { 421 return Args == Other.Args && DefaultArgEffect == Other.DefaultArgEffect && 422 Receiver == Other.Receiver && Ret == Other.Ret; 423 } 424}; 425} // end anonymous namespace 426 427//===----------------------------------------------------------------------===// 428// Data structures for constructing summaries. 429//===----------------------------------------------------------------------===// 430 431namespace { 432class ObjCSummaryKey { 433 IdentifierInfo* II; 434 Selector S; 435public: 436 ObjCSummaryKey(IdentifierInfo* ii, Selector s) 437 : II(ii), S(s) {} 438 439 ObjCSummaryKey(const ObjCInterfaceDecl *d, Selector s) 440 : II(d ? d->getIdentifier() : 0), S(s) {} 441 442 ObjCSummaryKey(const ObjCInterfaceDecl *d, IdentifierInfo *ii, Selector s) 443 : II(d ? d->getIdentifier() : ii), S(s) {} 444 445 ObjCSummaryKey(Selector s) 446 : II(0), S(s) {} 447 448 IdentifierInfo* getIdentifier() const { return II; } 449 Selector getSelector() const { return S; } 450}; 451} 452 453namespace llvm { 454template <> struct DenseMapInfo<ObjCSummaryKey> { 455 static inline ObjCSummaryKey getEmptyKey() { 456 return ObjCSummaryKey(DenseMapInfo<IdentifierInfo*>::getEmptyKey(), 457 DenseMapInfo<Selector>::getEmptyKey()); 458 } 459 460 static inline ObjCSummaryKey getTombstoneKey() { 461 return ObjCSummaryKey(DenseMapInfo<IdentifierInfo*>::getTombstoneKey(), 462 DenseMapInfo<Selector>::getTombstoneKey()); 463 } 464 465 static unsigned getHashValue(const ObjCSummaryKey &V) { 466 return (DenseMapInfo<IdentifierInfo*>::getHashValue(V.getIdentifier()) 467 & 0x88888888) 468 | (DenseMapInfo<Selector>::getHashValue(V.getSelector()) 469 & 0x55555555); 470 } 471 472 static bool isEqual(const ObjCSummaryKey& LHS, const ObjCSummaryKey& RHS) { 473 return DenseMapInfo<IdentifierInfo*>::isEqual(LHS.getIdentifier(), 474 RHS.getIdentifier()) && 475 DenseMapInfo<Selector>::isEqual(LHS.getSelector(), 476 RHS.getSelector()); 477 } 478 479}; 480template <> 481struct isPodLike<ObjCSummaryKey> { static const bool value = true; }; 482} // end llvm namespace 483 484namespace { 485class ObjCSummaryCache { 486 typedef llvm::DenseMap<ObjCSummaryKey, RetainSummary*> MapTy; 487 MapTy M; 488public: 489 ObjCSummaryCache() {} 490 491 RetainSummary* find(const ObjCInterfaceDecl *D, IdentifierInfo *ClsName, 492 Selector S) { 493 // Lookup the method using the decl for the class @interface. If we 494 // have no decl, lookup using the class name. 495 return D ? find(D, S) : find(ClsName, S); 496 } 497 498 RetainSummary* find(const ObjCInterfaceDecl *D, Selector S) { 499 // Do a lookup with the (D,S) pair. If we find a match return 500 // the iterator. 501 ObjCSummaryKey K(D, S); 502 MapTy::iterator I = M.find(K); 503 504 if (I != M.end() || !D) 505 return I->second; 506 507 // Walk the super chain. If we find a hit with a parent, we'll end 508 // up returning that summary. We actually allow that key (null,S), as 509 // we cache summaries for the null ObjCInterfaceDecl* to allow us to 510 // generate initial summaries without having to worry about NSObject 511 // being declared. 512 // FIXME: We may change this at some point. 513 for (ObjCInterfaceDecl *C=D->getSuperClass() ;; C=C->getSuperClass()) { 514 if ((I = M.find(ObjCSummaryKey(C, S))) != M.end()) 515 break; 516 517 if (!C) 518 return NULL; 519 } 520 521 // Cache the summary with original key to make the next lookup faster 522 // and return the iterator. 523 RetainSummary *Summ = I->second; 524 M[K] = Summ; 525 return Summ; 526 } 527 528 RetainSummary* find(IdentifierInfo* II, Selector S) { 529 // FIXME: Class method lookup. Right now we dont' have a good way 530 // of going between IdentifierInfo* and the class hierarchy. 531 MapTy::iterator I = M.find(ObjCSummaryKey(II, S)); 532 533 if (I == M.end()) 534 I = M.find(ObjCSummaryKey(S)); 535 536 return I == M.end() ? NULL : I->second; 537 } 538 539 RetainSummary*& operator[](ObjCSummaryKey K) { 540 return M[K]; 541 } 542 543 RetainSummary*& operator[](Selector S) { 544 return M[ ObjCSummaryKey(S) ]; 545 } 546}; 547} // end anonymous namespace 548 549//===----------------------------------------------------------------------===// 550// Data structures for managing collections of summaries. 551//===----------------------------------------------------------------------===// 552 553namespace { 554class RetainSummaryManager { 555 556 //==-----------------------------------------------------------------==// 557 // Typedefs. 558 //==-----------------------------------------------------------------==// 559 560 typedef llvm::DenseMap<const FunctionDecl*, RetainSummary*> 561 FuncSummariesTy; 562 563 typedef ObjCSummaryCache ObjCMethodSummariesTy; 564 565 //==-----------------------------------------------------------------==// 566 // Data. 567 //==-----------------------------------------------------------------==// 568 569 /// Ctx - The ASTContext object for the analyzed ASTs. 570 ASTContext &Ctx; 571 572 /// GCEnabled - Records whether or not the analyzed code runs in GC mode. 573 const bool GCEnabled; 574 575 /// Records whether or not the analyzed code runs in ARC mode. 576 const bool ARCEnabled; 577 578 /// FuncSummaries - A map from FunctionDecls to summaries. 579 FuncSummariesTy FuncSummaries; 580 581 /// ObjCClassMethodSummaries - A map from selectors (for instance methods) 582 /// to summaries. 583 ObjCMethodSummariesTy ObjCClassMethodSummaries; 584 585 /// ObjCMethodSummaries - A map from selectors to summaries. 586 ObjCMethodSummariesTy ObjCMethodSummaries; 587 588 /// BPAlloc - A BumpPtrAllocator used for allocating summaries, ArgEffects, 589 /// and all other data used by the checker. 590 llvm::BumpPtrAllocator BPAlloc; 591 592 /// AF - A factory for ArgEffects objects. 593 ArgEffects::Factory AF; 594 595 /// ScratchArgs - A holding buffer for construct ArgEffects. 596 ArgEffects ScratchArgs; 597 598 /// ObjCAllocRetE - Default return effect for methods returning Objective-C 599 /// objects. 600 RetEffect ObjCAllocRetE; 601 602 /// ObjCInitRetE - Default return effect for init methods returning 603 /// Objective-C objects. 604 RetEffect ObjCInitRetE; 605 606 RetainSummary DefaultSummary; 607 RetainSummary* StopSummary; 608 609 //==-----------------------------------------------------------------==// 610 // Methods. 611 //==-----------------------------------------------------------------==// 612 613 /// getArgEffects - Returns a persistent ArgEffects object based on the 614 /// data in ScratchArgs. 615 ArgEffects getArgEffects(); 616 617 enum UnaryFuncKind { cfretain, cfrelease, cfmakecollectable }; 618 619public: 620 RetEffect getObjAllocRetEffect() const { return ObjCAllocRetE; } 621 622 RetainSummary* getUnarySummary(const FunctionType* FT, UnaryFuncKind func); 623 624 RetainSummary* getCFSummaryCreateRule(const FunctionDecl *FD); 625 RetainSummary* getCFSummaryGetRule(const FunctionDecl *FD); 626 RetainSummary* getCFCreateGetRuleSummary(const FunctionDecl *FD, 627 StringRef FName); 628 629 RetainSummary* getPersistentSummary(ArgEffects AE, RetEffect RetEff, 630 ArgEffect ReceiverEff = DoNothing, 631 ArgEffect DefaultEff = MayEscape); 632 633 RetainSummary* getPersistentSummary(RetEffect RE, 634 ArgEffect ReceiverEff = DoNothing, 635 ArgEffect DefaultEff = MayEscape) { 636 return getPersistentSummary(getArgEffects(), RE, ReceiverEff, DefaultEff); 637 } 638 639 RetainSummary *getPersistentStopSummary() { 640 if (StopSummary) 641 return StopSummary; 642 643 StopSummary = getPersistentSummary(RetEffect::MakeNoRet(), 644 StopTracking, StopTracking); 645 646 return StopSummary; 647 } 648 649 RetainSummary *getInitMethodSummary(QualType RetTy); 650 651 void InitializeClassMethodSummaries(); 652 void InitializeMethodSummaries(); 653private: 654 void addNSObjectClsMethSummary(Selector S, RetainSummary *Summ) { 655 ObjCClassMethodSummaries[S] = Summ; 656 } 657 658 void addNSObjectMethSummary(Selector S, RetainSummary *Summ) { 659 ObjCMethodSummaries[S] = Summ; 660 } 661 662 void addClassMethSummary(const char* Cls, const char* nullaryName, 663 RetainSummary *Summ) { 664 IdentifierInfo* ClsII = &Ctx.Idents.get(Cls); 665 Selector S = GetNullarySelector(nullaryName, Ctx); 666 ObjCClassMethodSummaries[ObjCSummaryKey(ClsII, S)] = Summ; 667 } 668 669 void addInstMethSummary(const char* Cls, const char* nullaryName, 670 RetainSummary *Summ) { 671 IdentifierInfo* ClsII = &Ctx.Idents.get(Cls); 672 Selector S = GetNullarySelector(nullaryName, Ctx); 673 ObjCMethodSummaries[ObjCSummaryKey(ClsII, S)] = Summ; 674 } 675 676 Selector generateSelector(va_list argp) { 677 SmallVector<IdentifierInfo*, 10> II; 678 679 while (const char* s = va_arg(argp, const char*)) 680 II.push_back(&Ctx.Idents.get(s)); 681 682 return Ctx.Selectors.getSelector(II.size(), &II[0]); 683 } 684 685 void addMethodSummary(IdentifierInfo *ClsII, ObjCMethodSummariesTy& Summaries, 686 RetainSummary* Summ, va_list argp) { 687 Selector S = generateSelector(argp); 688 Summaries[ObjCSummaryKey(ClsII, S)] = Summ; 689 } 690 691 void addInstMethSummary(const char* Cls, RetainSummary* Summ, ...) { 692 va_list argp; 693 va_start(argp, Summ); 694 addMethodSummary(&Ctx.Idents.get(Cls), ObjCMethodSummaries, Summ, argp); 695 va_end(argp); 696 } 697 698 void addClsMethSummary(const char* Cls, RetainSummary* Summ, ...) { 699 va_list argp; 700 va_start(argp, Summ); 701 addMethodSummary(&Ctx.Idents.get(Cls),ObjCClassMethodSummaries, Summ, argp); 702 va_end(argp); 703 } 704 705 void addClsMethSummary(IdentifierInfo *II, RetainSummary* Summ, ...) { 706 va_list argp; 707 va_start(argp, Summ); 708 addMethodSummary(II, ObjCClassMethodSummaries, Summ, argp); 709 va_end(argp); 710 } 711 712public: 713 714 RetainSummaryManager(ASTContext &ctx, bool gcenabled, bool usesARC) 715 : Ctx(ctx), 716 GCEnabled(gcenabled), 717 ARCEnabled(usesARC), 718 AF(BPAlloc), ScratchArgs(AF.getEmptyMap()), 719 ObjCAllocRetE(gcenabled 720 ? RetEffect::MakeGCNotOwned() 721 : (usesARC ? RetEffect::MakeARCNotOwned() 722 : RetEffect::MakeOwned(RetEffect::ObjC, true))), 723 ObjCInitRetE(gcenabled 724 ? RetEffect::MakeGCNotOwned() 725 : (usesARC ? RetEffect::MakeARCNotOwned() 726 : RetEffect::MakeOwnedWhenTrackedReceiver())), 727 DefaultSummary(AF.getEmptyMap() /* per-argument effects (none) */, 728 RetEffect::MakeNoRet() /* return effect */, 729 MayEscape, /* default argument effect */ 730 DoNothing /* receiver effect */), 731 StopSummary(0) { 732 733 InitializeClassMethodSummaries(); 734 InitializeMethodSummaries(); 735 } 736 737 RetainSummary* getSummary(const FunctionDecl *FD); 738 739 RetainSummary *getInstanceMethodSummary(const ObjCMessage &msg, 740 const ProgramState *state, 741 const LocationContext *LC); 742 743 RetainSummary* getInstanceMethodSummary(const ObjCMessage &msg, 744 const ObjCInterfaceDecl *ID) { 745 return getInstanceMethodSummary(msg.getSelector(), 0, 746 ID, msg.getMethodDecl(), msg.getType(Ctx)); 747 } 748 749 RetainSummary* getInstanceMethodSummary(Selector S, IdentifierInfo *ClsName, 750 const ObjCInterfaceDecl *ID, 751 const ObjCMethodDecl *MD, 752 QualType RetTy); 753 754 RetainSummary *getClassMethodSummary(Selector S, IdentifierInfo *ClsName, 755 const ObjCInterfaceDecl *ID, 756 const ObjCMethodDecl *MD, 757 QualType RetTy); 758 759 RetainSummary *getClassMethodSummary(const ObjCMessage &msg) { 760 const ObjCInterfaceDecl *Class = 0; 761 if (!msg.isInstanceMessage()) 762 Class = msg.getReceiverInterface(); 763 764 return getClassMethodSummary(msg.getSelector(), 765 Class? Class->getIdentifier() : 0, 766 Class, 767 msg.getMethodDecl(), msg.getType(Ctx)); 768 } 769 770 /// getMethodSummary - This version of getMethodSummary is used to query 771 /// the summary for the current method being analyzed. 772 RetainSummary *getMethodSummary(const ObjCMethodDecl *MD) { 773 // FIXME: Eventually this should be unneeded. 774 const ObjCInterfaceDecl *ID = MD->getClassInterface(); 775 Selector S = MD->getSelector(); 776 IdentifierInfo *ClsName = ID->getIdentifier(); 777 QualType ResultTy = MD->getResultType(); 778 779 if (MD->isInstanceMethod()) 780 return getInstanceMethodSummary(S, ClsName, ID, MD, ResultTy); 781 else 782 return getClassMethodSummary(S, ClsName, ID, MD, ResultTy); 783 } 784 785 RetainSummary* getCommonMethodSummary(const ObjCMethodDecl *MD, 786 Selector S, QualType RetTy); 787 788 void updateSummaryFromAnnotations(RetainSummary *&Summ, 789 const ObjCMethodDecl *MD); 790 791 void updateSummaryFromAnnotations(RetainSummary *&Summ, 792 const FunctionDecl *FD); 793 794 bool isGCEnabled() const { return GCEnabled; } 795 796 bool isARCEnabled() const { return ARCEnabled; } 797 798 bool isARCorGCEnabled() const { return GCEnabled || ARCEnabled; } 799 800 RetainSummary *copySummary(RetainSummary *OldSumm) { 801 RetainSummary *Summ = (RetainSummary*) BPAlloc.Allocate<RetainSummary>(); 802 new (Summ) RetainSummary(*OldSumm); 803 return Summ; 804 } 805}; 806 807// Used to avoid allocating long-term (BPAlloc'd) memory for default retain 808// summaries. If a function or method looks like it has a default summary, but 809// it has annotations, the annotations are added to the stack-based template 810// and then copied into managed memory. 811class RetainSummaryTemplate { 812 RetainSummaryManager &Manager; 813 RetainSummary *&RealSummary; 814 RetainSummary ScratchSummary; 815 bool Accessed; 816public: 817 RetainSummaryTemplate(RetainSummary *&real, const RetainSummary &base, 818 RetainSummaryManager &manager) 819 : Manager(manager), RealSummary(real), ScratchSummary(base), Accessed(false) 820 {} 821 822 ~RetainSummaryTemplate() { 823 if (!RealSummary && Accessed) 824 RealSummary = Manager.copySummary(&ScratchSummary); 825 } 826 827 RetainSummary &operator*() { 828 Accessed = true; 829 return RealSummary ? *RealSummary : ScratchSummary; 830 } 831 832 RetainSummary *operator->() { 833 Accessed = true; 834 return RealSummary ? RealSummary : &ScratchSummary; 835 } 836}; 837 838} // end anonymous namespace 839 840//===----------------------------------------------------------------------===// 841// Implementation of checker data structures. 842//===----------------------------------------------------------------------===// 843 844ArgEffects RetainSummaryManager::getArgEffects() { 845 ArgEffects AE = ScratchArgs; 846 ScratchArgs = AF.getEmptyMap(); 847 return AE; 848} 849 850RetainSummary* 851RetainSummaryManager::getPersistentSummary(ArgEffects AE, RetEffect RetEff, 852 ArgEffect ReceiverEff, 853 ArgEffect DefaultEff) { 854 // Create the summary and return it. 855 RetainSummary *Summ = (RetainSummary*) BPAlloc.Allocate<RetainSummary>(); 856 new (Summ) RetainSummary(AE, RetEff, DefaultEff, ReceiverEff); 857 return Summ; 858} 859 860//===----------------------------------------------------------------------===// 861// Summary creation for functions (largely uses of Core Foundation). 862//===----------------------------------------------------------------------===// 863 864static bool isRetain(const FunctionDecl *FD, StringRef FName) { 865 return FName.endswith("Retain"); 866} 867 868static bool isRelease(const FunctionDecl *FD, StringRef FName) { 869 return FName.endswith("Release"); 870} 871 872static bool isMakeCollectable(const FunctionDecl *FD, StringRef FName) { 873 // FIXME: Remove FunctionDecl parameter. 874 // FIXME: Is it really okay if MakeCollectable isn't a suffix? 875 return FName.find("MakeCollectable") != StringRef::npos; 876} 877 878RetainSummary* RetainSummaryManager::getSummary(const FunctionDecl *FD) { 879 // Look up a summary in our cache of FunctionDecls -> Summaries. 880 FuncSummariesTy::iterator I = FuncSummaries.find(FD); 881 if (I != FuncSummaries.end()) 882 return I->second; 883 884 // No summary? Generate one. 885 RetainSummary *S = 0; 886 887 do { 888 // We generate "stop" summaries for implicitly defined functions. 889 if (FD->isImplicit()) { 890 S = getPersistentStopSummary(); 891 break; 892 } 893 // For C++ methods, generate an implicit "stop" summary as well. We 894 // can relax this once we have a clear policy for C++ methods and 895 // ownership attributes. 896 if (isa<CXXMethodDecl>(FD)) { 897 S = getPersistentStopSummary(); 898 break; 899 } 900 901 // [PR 3337] Use 'getAs<FunctionType>' to strip away any typedefs on the 902 // function's type. 903 const FunctionType* FT = FD->getType()->getAs<FunctionType>(); 904 const IdentifierInfo *II = FD->getIdentifier(); 905 if (!II) 906 break; 907 908 StringRef FName = II->getName(); 909 910 // Strip away preceding '_'. Doing this here will effect all the checks 911 // down below. 912 FName = FName.substr(FName.find_first_not_of('_')); 913 914 // Inspect the result type. 915 QualType RetTy = FT->getResultType(); 916 917 // FIXME: This should all be refactored into a chain of "summary lookup" 918 // filters. 919 assert(ScratchArgs.isEmpty()); 920 921 if (FName == "pthread_create") { 922 // Part of: <rdar://problem/7299394>. This will be addressed 923 // better with IPA. 924 S = getPersistentStopSummary(); 925 } else if (FName == "NSMakeCollectable") { 926 // Handle: id NSMakeCollectable(CFTypeRef) 927 S = (RetTy->isObjCIdType()) 928 ? getUnarySummary(FT, cfmakecollectable) 929 : getPersistentStopSummary(); 930 } else if (FName == "IOBSDNameMatching" || 931 FName == "IOServiceMatching" || 932 FName == "IOServiceNameMatching" || 933 FName == "IORegistryEntryIDMatching" || 934 FName == "IOOpenFirmwarePathMatching") { 935 // Part of <rdar://problem/6961230>. (IOKit) 936 // This should be addressed using a API table. 937 S = getPersistentSummary(RetEffect::MakeOwned(RetEffect::CF, true), 938 DoNothing, DoNothing); 939 } else if (FName == "IOServiceGetMatchingService" || 940 FName == "IOServiceGetMatchingServices") { 941 // FIXES: <rdar://problem/6326900> 942 // This should be addressed using a API table. This strcmp is also 943 // a little gross, but there is no need to super optimize here. 944 ScratchArgs = AF.add(ScratchArgs, 1, DecRef); 945 S = getPersistentSummary(RetEffect::MakeNoRet(), DoNothing, DoNothing); 946 } else if (FName == "IOServiceAddNotification" || 947 FName == "IOServiceAddMatchingNotification") { 948 // Part of <rdar://problem/6961230>. (IOKit) 949 // This should be addressed using a API table. 950 ScratchArgs = AF.add(ScratchArgs, 2, DecRef); 951 S = getPersistentSummary(RetEffect::MakeNoRet(), DoNothing, DoNothing); 952 } else if (FName == "CVPixelBufferCreateWithBytes") { 953 // FIXES: <rdar://problem/7283567> 954 // Eventually this can be improved by recognizing that the pixel 955 // buffer passed to CVPixelBufferCreateWithBytes is released via 956 // a callback and doing full IPA to make sure this is done correctly. 957 // FIXME: This function has an out parameter that returns an 958 // allocated object. 959 ScratchArgs = AF.add(ScratchArgs, 7, StopTracking); 960 S = getPersistentSummary(RetEffect::MakeNoRet(), DoNothing, DoNothing); 961 } else if (FName == "CGBitmapContextCreateWithData") { 962 // FIXES: <rdar://problem/7358899> 963 // Eventually this can be improved by recognizing that 'releaseInfo' 964 // passed to CGBitmapContextCreateWithData is released via 965 // a callback and doing full IPA to make sure this is done correctly. 966 ScratchArgs = AF.add(ScratchArgs, 8, StopTracking); 967 S = getPersistentSummary(RetEffect::MakeOwned(RetEffect::CF, true), 968 DoNothing, DoNothing); 969 } else if (FName == "CVPixelBufferCreateWithPlanarBytes") { 970 // FIXES: <rdar://problem/7283567> 971 // Eventually this can be improved by recognizing that the pixel 972 // buffer passed to CVPixelBufferCreateWithPlanarBytes is released 973 // via a callback and doing full IPA to make sure this is done 974 // correctly. 975 ScratchArgs = AF.add(ScratchArgs, 12, StopTracking); 976 S = getPersistentSummary(RetEffect::MakeNoRet(), DoNothing, DoNothing); 977 } 978 979 // Did we get a summary? 980 if (S) 981 break; 982 983 // Enable this code once the semantics of NSDeallocateObject are resolved 984 // for GC. <rdar://problem/6619988> 985#if 0 986 // Handle: NSDeallocateObject(id anObject); 987 // This method does allow 'nil' (although we don't check it now). 988 if (strcmp(FName, "NSDeallocateObject") == 0) { 989 return RetTy == Ctx.VoidTy 990 ? getPersistentSummary(RetEffect::MakeNoRet(), DoNothing, Dealloc) 991 : getPersistentStopSummary(); 992 } 993#endif 994 995 if (RetTy->isPointerType()) { 996 // For CoreFoundation ('CF') types. 997 if (cocoa::isRefType(RetTy, "CF", FName)) { 998 if (isRetain(FD, FName)) 999 S = getUnarySummary(FT, cfretain); 1000 else if (isMakeCollectable(FD, FName)) 1001 S = getUnarySummary(FT, cfmakecollectable); 1002 else 1003 S = getCFCreateGetRuleSummary(FD, FName); 1004 1005 break; 1006 } 1007 1008 // For CoreGraphics ('CG') types. 1009 if (cocoa::isRefType(RetTy, "CG", FName)) { 1010 if (isRetain(FD, FName)) 1011 S = getUnarySummary(FT, cfretain); 1012 else 1013 S = getCFCreateGetRuleSummary(FD, FName); 1014 1015 break; 1016 } 1017 1018 // For the Disk Arbitration API (DiskArbitration/DADisk.h) 1019 if (cocoa::isRefType(RetTy, "DADisk") || 1020 cocoa::isRefType(RetTy, "DADissenter") || 1021 cocoa::isRefType(RetTy, "DASessionRef")) { 1022 S = getCFCreateGetRuleSummary(FD, FName); 1023 break; 1024 } 1025 1026 break; 1027 } 1028 1029 // Check for release functions, the only kind of functions that we care 1030 // about that don't return a pointer type. 1031 if (FName[0] == 'C' && (FName[1] == 'F' || FName[1] == 'G')) { 1032 // Test for 'CGCF'. 1033 FName = FName.substr(FName.startswith("CGCF") ? 4 : 2); 1034 1035 if (isRelease(FD, FName)) 1036 S = getUnarySummary(FT, cfrelease); 1037 else { 1038 assert (ScratchArgs.isEmpty()); 1039 // Remaining CoreFoundation and CoreGraphics functions. 1040 // We use to assume that they all strictly followed the ownership idiom 1041 // and that ownership cannot be transferred. While this is technically 1042 // correct, many methods allow a tracked object to escape. For example: 1043 // 1044 // CFMutableDictionaryRef x = CFDictionaryCreateMutable(...); 1045 // CFDictionaryAddValue(y, key, x); 1046 // CFRelease(x); 1047 // ... it is okay to use 'x' since 'y' has a reference to it 1048 // 1049 // We handle this and similar cases with the follow heuristic. If the 1050 // function name contains "InsertValue", "SetValue", "AddValue", 1051 // "AppendValue", or "SetAttribute", then we assume that arguments may 1052 // "escape." This means that something else holds on to the object, 1053 // allowing it be used even after its local retain count drops to 0. 1054 ArgEffect E = (StrInStrNoCase(FName, "InsertValue") != StringRef::npos|| 1055 StrInStrNoCase(FName, "AddValue") != StringRef::npos || 1056 StrInStrNoCase(FName, "SetValue") != StringRef::npos || 1057 StrInStrNoCase(FName, "AppendValue") != StringRef::npos|| 1058 StrInStrNoCase(FName, "SetAttribute") != StringRef::npos) 1059 ? MayEscape : DoNothing; 1060 1061 S = getPersistentSummary(RetEffect::MakeNoRet(), DoNothing, E); 1062 } 1063 } 1064 } 1065 while (0); 1066 1067 // Annotations override defaults. 1068 updateSummaryFromAnnotations(S, FD); 1069 1070 FuncSummaries[FD] = S; 1071 return S; 1072} 1073 1074RetainSummary* 1075RetainSummaryManager::getCFCreateGetRuleSummary(const FunctionDecl *FD, 1076 StringRef FName) { 1077 if (coreFoundation::followsCreateRule(FName)) 1078 return getCFSummaryCreateRule(FD); 1079 1080 return getCFSummaryGetRule(FD); 1081} 1082 1083RetainSummary* 1084RetainSummaryManager::getUnarySummary(const FunctionType* FT, 1085 UnaryFuncKind func) { 1086 1087 // Sanity check that this is *really* a unary function. This can 1088 // happen if people do weird things. 1089 const FunctionProtoType* FTP = dyn_cast<FunctionProtoType>(FT); 1090 if (!FTP || FTP->getNumArgs() != 1) 1091 return getPersistentStopSummary(); 1092 1093 assert (ScratchArgs.isEmpty()); 1094 1095 ArgEffect Effect; 1096 switch (func) { 1097 case cfretain: Effect = IncRef; break; 1098 case cfrelease: Effect = DecRef; break; 1099 case cfmakecollectable: Effect = MakeCollectable; break; 1100 default: llvm_unreachable("Not a supported unary function."); 1101 } 1102 1103 ScratchArgs = AF.add(ScratchArgs, 0, Effect); 1104 return getPersistentSummary(RetEffect::MakeNoRet(), DoNothing, DoNothing); 1105} 1106 1107RetainSummary* 1108RetainSummaryManager::getCFSummaryCreateRule(const FunctionDecl *FD) { 1109 assert (ScratchArgs.isEmpty()); 1110 1111 return getPersistentSummary(RetEffect::MakeOwned(RetEffect::CF, true)); 1112} 1113 1114RetainSummary* 1115RetainSummaryManager::getCFSummaryGetRule(const FunctionDecl *FD) { 1116 assert (ScratchArgs.isEmpty()); 1117 return getPersistentSummary(RetEffect::MakeNotOwned(RetEffect::CF), 1118 DoNothing, DoNothing); 1119} 1120 1121//===----------------------------------------------------------------------===// 1122// Summary creation for Selectors. 1123//===----------------------------------------------------------------------===// 1124 1125RetainSummary* 1126RetainSummaryManager::getInitMethodSummary(QualType RetTy) { 1127 assert(ScratchArgs.isEmpty()); 1128 // 'init' methods conceptually return a newly allocated object and claim 1129 // the receiver. 1130 if (cocoa::isCocoaObjectRef(RetTy) || 1131 coreFoundation::isCFObjectRef(RetTy)) 1132 return getPersistentSummary(ObjCInitRetE, DecRefMsg); 1133 1134 return 0; 1135} 1136 1137void 1138RetainSummaryManager::updateSummaryFromAnnotations(RetainSummary *&Summ, 1139 const FunctionDecl *FD) { 1140 if (!FD) 1141 return; 1142 1143 RetainSummaryTemplate Template(Summ, DefaultSummary, *this); 1144 1145 // Effects on the parameters. 1146 unsigned parm_idx = 0; 1147 for (FunctionDecl::param_const_iterator pi = FD->param_begin(), 1148 pe = FD->param_end(); pi != pe; ++pi, ++parm_idx) { 1149 const ParmVarDecl *pd = *pi; 1150 if (pd->getAttr<NSConsumedAttr>()) { 1151 if (!GCEnabled) { 1152 Template->addArg(AF, parm_idx, DecRef); 1153 } 1154 } else if (pd->getAttr<CFConsumedAttr>()) { 1155 Template->addArg(AF, parm_idx, DecRef); 1156 } 1157 } 1158 1159 QualType RetTy = FD->getResultType(); 1160 1161 // Determine if there is a special return effect for this method. 1162 if (cocoa::isCocoaObjectRef(RetTy)) { 1163 if (FD->getAttr<NSReturnsRetainedAttr>()) { 1164 Template->setRetEffect(ObjCAllocRetE); 1165 } 1166 else if (FD->getAttr<CFReturnsRetainedAttr>()) { 1167 Template->setRetEffect(RetEffect::MakeOwned(RetEffect::CF, true)); 1168 } 1169 else if (FD->getAttr<NSReturnsNotRetainedAttr>()) { 1170 Template->setRetEffect(RetEffect::MakeNotOwned(RetEffect::ObjC)); 1171 } 1172 else if (FD->getAttr<CFReturnsNotRetainedAttr>()) { 1173 Template->setRetEffect(RetEffect::MakeNotOwned(RetEffect::CF)); 1174 } 1175 } else if (RetTy->getAs<PointerType>()) { 1176 if (FD->getAttr<CFReturnsRetainedAttr>()) { 1177 Template->setRetEffect(RetEffect::MakeOwned(RetEffect::CF, true)); 1178 } 1179 else if (FD->getAttr<CFReturnsNotRetainedAttr>()) { 1180 Template->setRetEffect(RetEffect::MakeNotOwned(RetEffect::CF)); 1181 } 1182 } 1183} 1184 1185void 1186RetainSummaryManager::updateSummaryFromAnnotations(RetainSummary *&Summ, 1187 const ObjCMethodDecl *MD) { 1188 if (!MD) 1189 return; 1190 1191 RetainSummaryTemplate Template(Summ, DefaultSummary, *this); 1192 1193 bool isTrackedLoc = false; 1194 1195 // Effects on the receiver. 1196 if (MD->getAttr<NSConsumesSelfAttr>()) { 1197 if (!GCEnabled) 1198 Template->setReceiverEffect(DecRefMsg); 1199 } 1200 1201 // Effects on the parameters. 1202 unsigned parm_idx = 0; 1203 for (ObjCMethodDecl::param_iterator pi=MD->param_begin(), pe=MD->param_end(); 1204 pi != pe; ++pi, ++parm_idx) { 1205 const ParmVarDecl *pd = *pi; 1206 if (pd->getAttr<NSConsumedAttr>()) { 1207 if (!GCEnabled) 1208 Template->addArg(AF, parm_idx, DecRef); 1209 } 1210 else if(pd->getAttr<CFConsumedAttr>()) { 1211 Template->addArg(AF, parm_idx, DecRef); 1212 } 1213 } 1214 1215 // Determine if there is a special return effect for this method. 1216 if (cocoa::isCocoaObjectRef(MD->getResultType())) { 1217 if (MD->getAttr<NSReturnsRetainedAttr>()) { 1218 Template->setRetEffect(ObjCAllocRetE); 1219 return; 1220 } 1221 if (MD->getAttr<NSReturnsNotRetainedAttr>()) { 1222 Template->setRetEffect(RetEffect::MakeNotOwned(RetEffect::ObjC)); 1223 return; 1224 } 1225 1226 isTrackedLoc = true; 1227 } else { 1228 isTrackedLoc = MD->getResultType()->getAs<PointerType>() != NULL; 1229 } 1230 1231 if (isTrackedLoc) { 1232 if (MD->getAttr<CFReturnsRetainedAttr>()) 1233 Template->setRetEffect(RetEffect::MakeOwned(RetEffect::CF, true)); 1234 else if (MD->getAttr<CFReturnsNotRetainedAttr>()) 1235 Template->setRetEffect(RetEffect::MakeNotOwned(RetEffect::CF)); 1236 } 1237} 1238 1239RetainSummary* 1240RetainSummaryManager::getCommonMethodSummary(const ObjCMethodDecl *MD, 1241 Selector S, QualType RetTy) { 1242 1243 if (MD) { 1244 // Scan the method decl for 'void*' arguments. These should be treated 1245 // as 'StopTracking' because they are often used with delegates. 1246 // Delegates are a frequent form of false positives with the retain 1247 // count checker. 1248 unsigned i = 0; 1249 for (ObjCMethodDecl::param_iterator I = MD->param_begin(), 1250 E = MD->param_end(); I != E; ++I, ++i) 1251 if (ParmVarDecl *PD = *I) { 1252 QualType Ty = Ctx.getCanonicalType(PD->getType()); 1253 if (Ty.getLocalUnqualifiedType() == Ctx.VoidPtrTy) 1254 ScratchArgs = AF.add(ScratchArgs, i, StopTracking); 1255 } 1256 } 1257 1258 // Any special effect for the receiver? 1259 ArgEffect ReceiverEff = DoNothing; 1260 1261 // If one of the arguments in the selector has the keyword 'delegate' we 1262 // should stop tracking the reference count for the receiver. This is 1263 // because the reference count is quite possibly handled by a delegate 1264 // method. 1265 if (S.isKeywordSelector()) { 1266 const std::string &str = S.getAsString(); 1267 assert(!str.empty()); 1268 if (StrInStrNoCase(str, "delegate:") != StringRef::npos) 1269 ReceiverEff = StopTracking; 1270 } 1271 1272 // Look for methods that return an owned object. 1273 if (cocoa::isCocoaObjectRef(RetTy)) { 1274 // EXPERIMENTAL: assume the Cocoa conventions for all objects returned 1275 // by instance methods. 1276 RetEffect E = cocoa::followsFundamentalRule(S, MD) 1277 ? ObjCAllocRetE : RetEffect::MakeNotOwned(RetEffect::ObjC); 1278 1279 return getPersistentSummary(E, ReceiverEff, MayEscape); 1280 } 1281 1282 // Look for methods that return an owned core foundation object. 1283 if (coreFoundation::isCFObjectRef(RetTy)) { 1284 RetEffect E = cocoa::followsFundamentalRule(S, MD) 1285 ? RetEffect::MakeOwned(RetEffect::CF, true) 1286 : RetEffect::MakeNotOwned(RetEffect::CF); 1287 1288 return getPersistentSummary(E, ReceiverEff, MayEscape); 1289 } 1290 1291 if (ScratchArgs.isEmpty() && ReceiverEff == DoNothing) 1292 return 0; 1293 1294 return getPersistentSummary(RetEffect::MakeNoRet(), ReceiverEff, MayEscape); 1295} 1296 1297RetainSummary* 1298RetainSummaryManager::getInstanceMethodSummary(const ObjCMessage &msg, 1299 const ProgramState *state, 1300 const LocationContext *LC) { 1301 1302 // We need the type-information of the tracked receiver object 1303 // Retrieve it from the state. 1304 const Expr *Receiver = msg.getInstanceReceiver(); 1305 const ObjCInterfaceDecl *ID = 0; 1306 1307 // FIXME: Is this really working as expected? There are cases where 1308 // we just use the 'ID' from the message expression. 1309 SVal receiverV; 1310 1311 if (Receiver) { 1312 receiverV = state->getSValAsScalarOrLoc(Receiver); 1313 1314 // FIXME: Eventually replace the use of state->get<RefBindings> with 1315 // a generic API for reasoning about the Objective-C types of symbolic 1316 // objects. 1317 if (SymbolRef Sym = receiverV.getAsLocSymbol()) 1318 if (const RefVal *T = state->get<RefBindings>(Sym)) 1319 if (const ObjCObjectPointerType* PT = 1320 T->getType()->getAs<ObjCObjectPointerType>()) 1321 ID = PT->getInterfaceDecl(); 1322 1323 // FIXME: this is a hack. This may or may not be the actual method 1324 // that is called. 1325 if (!ID) { 1326 if (const ObjCObjectPointerType *PT = 1327 Receiver->getType()->getAs<ObjCObjectPointerType>()) 1328 ID = PT->getInterfaceDecl(); 1329 } 1330 } else { 1331 // FIXME: Hack for 'super'. 1332 ID = msg.getReceiverInterface(); 1333 } 1334 1335 // FIXME: The receiver could be a reference to a class, meaning that 1336 // we should use the class method. 1337 return getInstanceMethodSummary(msg, ID); 1338} 1339 1340RetainSummary* 1341RetainSummaryManager::getInstanceMethodSummary(Selector S, 1342 IdentifierInfo *ClsName, 1343 const ObjCInterfaceDecl *ID, 1344 const ObjCMethodDecl *MD, 1345 QualType RetTy) { 1346 1347 // Look up a summary in our summary cache. 1348 RetainSummary *Summ = ObjCMethodSummaries.find(ID, ClsName, S); 1349 1350 if (!Summ) { 1351 assert(ScratchArgs.isEmpty()); 1352 1353 // "initXXX": pass-through for receiver. 1354 if (cocoa::deriveNamingConvention(S, MD) == cocoa::InitRule) 1355 Summ = getInitMethodSummary(RetTy); 1356 else 1357 Summ = getCommonMethodSummary(MD, S, RetTy); 1358 1359 // Annotations override defaults. 1360 updateSummaryFromAnnotations(Summ, MD); 1361 1362 // Memoize the summary. 1363 ObjCMethodSummaries[ObjCSummaryKey(ID, ClsName, S)] = Summ; 1364 } 1365 1366 return Summ; 1367} 1368 1369RetainSummary* 1370RetainSummaryManager::getClassMethodSummary(Selector S, IdentifierInfo *ClsName, 1371 const ObjCInterfaceDecl *ID, 1372 const ObjCMethodDecl *MD, 1373 QualType RetTy) { 1374 1375 assert(ClsName && "Class name must be specified."); 1376 RetainSummary *Summ = ObjCClassMethodSummaries.find(ID, ClsName, S); 1377 1378 if (!Summ) { 1379 Summ = getCommonMethodSummary(MD, S, RetTy); 1380 1381 // Annotations override defaults. 1382 updateSummaryFromAnnotations(Summ, MD); 1383 1384 // Memoize the summary. 1385 ObjCClassMethodSummaries[ObjCSummaryKey(ID, ClsName, S)] = Summ; 1386 } 1387 1388 return Summ; 1389} 1390 1391void RetainSummaryManager::InitializeClassMethodSummaries() { 1392 assert(ScratchArgs.isEmpty()); 1393 // Create the [NSAssertionHandler currentHander] summary. 1394 addClassMethSummary("NSAssertionHandler", "currentHandler", 1395 getPersistentSummary(RetEffect::MakeNotOwned(RetEffect::ObjC))); 1396 1397 // Create the [NSAutoreleasePool addObject:] summary. 1398 ScratchArgs = AF.add(ScratchArgs, 0, Autorelease); 1399 addClassMethSummary("NSAutoreleasePool", "addObject", 1400 getPersistentSummary(RetEffect::MakeNoRet(), 1401 DoNothing, Autorelease)); 1402 1403 // Create the summaries for [NSObject performSelector...]. We treat 1404 // these as 'stop tracking' for the arguments because they are often 1405 // used for delegates that can release the object. When we have better 1406 // inter-procedural analysis we can potentially do something better. This 1407 // workaround is to remove false positives. 1408 RetainSummary *Summ = 1409 getPersistentSummary(RetEffect::MakeNoRet(), DoNothing, StopTracking); 1410 IdentifierInfo *NSObjectII = &Ctx.Idents.get("NSObject"); 1411 addClsMethSummary(NSObjectII, Summ, "performSelector", "withObject", 1412 "afterDelay", NULL); 1413 addClsMethSummary(NSObjectII, Summ, "performSelector", "withObject", 1414 "afterDelay", "inModes", NULL); 1415 addClsMethSummary(NSObjectII, Summ, "performSelectorOnMainThread", 1416 "withObject", "waitUntilDone", NULL); 1417 addClsMethSummary(NSObjectII, Summ, "performSelectorOnMainThread", 1418 "withObject", "waitUntilDone", "modes", NULL); 1419 addClsMethSummary(NSObjectII, Summ, "performSelector", "onThread", 1420 "withObject", "waitUntilDone", NULL); 1421 addClsMethSummary(NSObjectII, Summ, "performSelector", "onThread", 1422 "withObject", "waitUntilDone", "modes", NULL); 1423 addClsMethSummary(NSObjectII, Summ, "performSelectorInBackground", 1424 "withObject", NULL); 1425} 1426 1427void RetainSummaryManager::InitializeMethodSummaries() { 1428 1429 assert (ScratchArgs.isEmpty()); 1430 1431 // Create the "init" selector. It just acts as a pass-through for the 1432 // receiver. 1433 RetainSummary *InitSumm = getPersistentSummary(ObjCInitRetE, DecRefMsg); 1434 addNSObjectMethSummary(GetNullarySelector("init", Ctx), InitSumm); 1435 1436 // awakeAfterUsingCoder: behaves basically like an 'init' method. It 1437 // claims the receiver and returns a retained object. 1438 addNSObjectMethSummary(GetUnarySelector("awakeAfterUsingCoder", Ctx), 1439 InitSumm); 1440 1441 // The next methods are allocators. 1442 RetainSummary *AllocSumm = getPersistentSummary(ObjCAllocRetE); 1443 RetainSummary *CFAllocSumm = 1444 getPersistentSummary(RetEffect::MakeOwned(RetEffect::CF, true)); 1445 1446 // Create the "retain" selector. 1447 RetEffect NoRet = RetEffect::MakeNoRet(); 1448 RetainSummary *Summ = getPersistentSummary(NoRet, IncRefMsg); 1449 addNSObjectMethSummary(GetNullarySelector("retain", Ctx), Summ); 1450 1451 // Create the "release" selector. 1452 Summ = getPersistentSummary(NoRet, DecRefMsg); 1453 addNSObjectMethSummary(GetNullarySelector("release", Ctx), Summ); 1454 1455 // Create the "drain" selector. 1456 Summ = getPersistentSummary(NoRet, isGCEnabled() ? DoNothing : DecRef); 1457 addNSObjectMethSummary(GetNullarySelector("drain", Ctx), Summ); 1458 1459 // Create the -dealloc summary. 1460 Summ = getPersistentSummary(NoRet, Dealloc); 1461 addNSObjectMethSummary(GetNullarySelector("dealloc", Ctx), Summ); 1462 1463 // Create the "autorelease" selector. 1464 Summ = getPersistentSummary(NoRet, Autorelease); 1465 addNSObjectMethSummary(GetNullarySelector("autorelease", Ctx), Summ); 1466 1467 // Specially handle NSAutoreleasePool. 1468 addInstMethSummary("NSAutoreleasePool", "init", 1469 getPersistentSummary(NoRet, NewAutoreleasePool)); 1470 1471 // For NSWindow, allocated objects are (initially) self-owned. 1472 // FIXME: For now we opt for false negatives with NSWindow, as these objects 1473 // self-own themselves. However, they only do this once they are displayed. 1474 // Thus, we need to track an NSWindow's display status. 1475 // This is tracked in <rdar://problem/6062711>. 1476 // See also http://llvm.org/bugs/show_bug.cgi?id=3714. 1477 RetainSummary *NoTrackYet = getPersistentSummary(RetEffect::MakeNoRet(), 1478 StopTracking, 1479 StopTracking); 1480 1481 addClassMethSummary("NSWindow", "alloc", NoTrackYet); 1482 1483#if 0 1484 addInstMethSummary("NSWindow", NoTrackYet, "initWithContentRect", 1485 "styleMask", "backing", "defer", NULL); 1486 1487 addInstMethSummary("NSWindow", NoTrackYet, "initWithContentRect", 1488 "styleMask", "backing", "defer", "screen", NULL); 1489#endif 1490 1491 // For NSPanel (which subclasses NSWindow), allocated objects are not 1492 // self-owned. 1493 // FIXME: For now we don't track NSPanels. object for the same reason 1494 // as for NSWindow objects. 1495 addClassMethSummary("NSPanel", "alloc", NoTrackYet); 1496 1497#if 0 1498 addInstMethSummary("NSPanel", NoTrackYet, "initWithContentRect", 1499 "styleMask", "backing", "defer", NULL); 1500 1501 addInstMethSummary("NSPanel", NoTrackYet, "initWithContentRect", 1502 "styleMask", "backing", "defer", "screen", NULL); 1503#endif 1504 1505 // Don't track allocated autorelease pools yet, as it is okay to prematurely 1506 // exit a method. 1507 addClassMethSummary("NSAutoreleasePool", "alloc", NoTrackYet); 1508 1509 // Create summaries QCRenderer/QCView -createSnapShotImageOfType: 1510 addInstMethSummary("QCRenderer", AllocSumm, 1511 "createSnapshotImageOfType", NULL); 1512 addInstMethSummary("QCView", AllocSumm, 1513 "createSnapshotImageOfType", NULL); 1514 1515 // Create summaries for CIContext, 'createCGImage' and 1516 // 'createCGLayerWithSize'. These objects are CF objects, and are not 1517 // automatically garbage collected. 1518 addInstMethSummary("CIContext", CFAllocSumm, 1519 "createCGImage", "fromRect", NULL); 1520 addInstMethSummary("CIContext", CFAllocSumm, 1521 "createCGImage", "fromRect", "format", "colorSpace", NULL); 1522 addInstMethSummary("CIContext", CFAllocSumm, "createCGLayerWithSize", 1523 "info", NULL); 1524} 1525 1526//===----------------------------------------------------------------------===// 1527// AutoreleaseBindings - State used to track objects in autorelease pools. 1528//===----------------------------------------------------------------------===// 1529 1530typedef llvm::ImmutableMap<SymbolRef, unsigned> ARCounts; 1531typedef llvm::ImmutableMap<SymbolRef, ARCounts> ARPoolContents; 1532typedef llvm::ImmutableList<SymbolRef> ARStack; 1533 1534static int AutoRCIndex = 0; 1535static int AutoRBIndex = 0; 1536 1537namespace { class AutoreleasePoolContents {}; } 1538namespace { class AutoreleaseStack {}; } 1539 1540namespace clang { 1541namespace ento { 1542template<> struct ProgramStateTrait<AutoreleaseStack> 1543 : public ProgramStatePartialTrait<ARStack> { 1544 static inline void *GDMIndex() { return &AutoRBIndex; } 1545}; 1546 1547template<> struct ProgramStateTrait<AutoreleasePoolContents> 1548 : public ProgramStatePartialTrait<ARPoolContents> { 1549 static inline void *GDMIndex() { return &AutoRCIndex; } 1550}; 1551} // end GR namespace 1552} // end clang namespace 1553 1554static SymbolRef GetCurrentAutoreleasePool(const ProgramState *state) { 1555 ARStack stack = state->get<AutoreleaseStack>(); 1556 return stack.isEmpty() ? SymbolRef() : stack.getHead(); 1557} 1558 1559static const ProgramState * 1560SendAutorelease(const ProgramState *state, 1561 ARCounts::Factory &F, 1562 SymbolRef sym) { 1563 SymbolRef pool = GetCurrentAutoreleasePool(state); 1564 const ARCounts *cnts = state->get<AutoreleasePoolContents>(pool); 1565 ARCounts newCnts(0); 1566 1567 if (cnts) { 1568 const unsigned *cnt = (*cnts).lookup(sym); 1569 newCnts = F.add(*cnts, sym, cnt ? *cnt + 1 : 1); 1570 } 1571 else 1572 newCnts = F.add(F.getEmptyMap(), sym, 1); 1573 1574 return state->set<AutoreleasePoolContents>(pool, newCnts); 1575} 1576 1577//===----------------------------------------------------------------------===// 1578// Error reporting. 1579//===----------------------------------------------------------------------===// 1580namespace { 1581 typedef llvm::DenseMap<const ExplodedNode *, const RetainSummary *> 1582 SummaryLogTy; 1583 1584 //===-------------===// 1585 // Bug Descriptions. // 1586 //===-------------===// 1587 1588 class CFRefBug : public BugType { 1589 protected: 1590 CFRefBug(StringRef name) 1591 : BugType(name, "Memory (Core Foundation/Objective-C)") {} 1592 public: 1593 1594 // FIXME: Eventually remove. 1595 virtual const char *getDescription() const = 0; 1596 1597 virtual bool isLeak() const { return false; } 1598 }; 1599 1600 class UseAfterRelease : public CFRefBug { 1601 public: 1602 UseAfterRelease() : CFRefBug("Use-after-release") {} 1603 1604 const char *getDescription() const { 1605 return "Reference-counted object is used after it is released"; 1606 } 1607 }; 1608 1609 class BadRelease : public CFRefBug { 1610 public: 1611 BadRelease() : CFRefBug("Bad release") {} 1612 1613 const char *getDescription() const { 1614 return "Incorrect decrement of the reference count of an object that is " 1615 "not owned at this point by the caller"; 1616 } 1617 }; 1618 1619 class DeallocGC : public CFRefBug { 1620 public: 1621 DeallocGC() 1622 : CFRefBug("-dealloc called while using garbage collection") {} 1623 1624 const char *getDescription() const { 1625 return "-dealloc called while using garbage collection"; 1626 } 1627 }; 1628 1629 class DeallocNotOwned : public CFRefBug { 1630 public: 1631 DeallocNotOwned() 1632 : CFRefBug("-dealloc sent to non-exclusively owned object") {} 1633 1634 const char *getDescription() const { 1635 return "-dealloc sent to object that may be referenced elsewhere"; 1636 } 1637 }; 1638 1639 class OverAutorelease : public CFRefBug { 1640 public: 1641 OverAutorelease() 1642 : CFRefBug("Object sent -autorelease too many times") {} 1643 1644 const char *getDescription() const { 1645 return "Object sent -autorelease too many times"; 1646 } 1647 }; 1648 1649 class ReturnedNotOwnedForOwned : public CFRefBug { 1650 public: 1651 ReturnedNotOwnedForOwned() 1652 : CFRefBug("Method should return an owned object") {} 1653 1654 const char *getDescription() const { 1655 return "Object with a +0 retain count returned to caller where a +1 " 1656 "(owning) retain count is expected"; 1657 } 1658 }; 1659 1660 class Leak : public CFRefBug { 1661 const bool isReturn; 1662 protected: 1663 Leak(StringRef name, bool isRet) 1664 : CFRefBug(name), isReturn(isRet) { 1665 // Leaks should not be reported if they are post-dominated by a sink. 1666 setSuppressOnSink(true); 1667 } 1668 public: 1669 1670 const char *getDescription() const { return ""; } 1671 1672 bool isLeak() const { return true; } 1673 }; 1674 1675 class LeakAtReturn : public Leak { 1676 public: 1677 LeakAtReturn(StringRef name) 1678 : Leak(name, true) {} 1679 }; 1680 1681 class LeakWithinFunction : public Leak { 1682 public: 1683 LeakWithinFunction(StringRef name) 1684 : Leak(name, false) {} 1685 }; 1686 1687 //===---------===// 1688 // Bug Reports. // 1689 //===---------===// 1690 1691 class CFRefReportVisitor : public BugReporterVisitor { 1692 protected: 1693 SymbolRef Sym; 1694 const SummaryLogTy &SummaryLog; 1695 bool GCEnabled; 1696 1697 public: 1698 CFRefReportVisitor(SymbolRef sym, bool gcEnabled, const SummaryLogTy &log) 1699 : Sym(sym), SummaryLog(log), GCEnabled(gcEnabled) {} 1700 1701 virtual void Profile(llvm::FoldingSetNodeID &ID) const { 1702 static int x = 0; 1703 ID.AddPointer(&x); 1704 ID.AddPointer(Sym); 1705 } 1706 1707 virtual PathDiagnosticPiece *VisitNode(const ExplodedNode *N, 1708 const ExplodedNode *PrevN, 1709 BugReporterContext &BRC, 1710 BugReport &BR); 1711 1712 virtual PathDiagnosticPiece *getEndPath(BugReporterContext &BRC, 1713 const ExplodedNode *N, 1714 BugReport &BR); 1715 }; 1716 1717 class CFRefLeakReportVisitor : public CFRefReportVisitor { 1718 public: 1719 CFRefLeakReportVisitor(SymbolRef sym, bool GCEnabled, 1720 const SummaryLogTy &log) 1721 : CFRefReportVisitor(sym, GCEnabled, log) {} 1722 1723 PathDiagnosticPiece *getEndPath(BugReporterContext &BRC, 1724 const ExplodedNode *N, 1725 BugReport &BR); 1726 }; 1727 1728 class CFRefReport : public BugReport { 1729 void addGCModeDescription(const LangOptions &LOpts, bool GCEnabled); 1730 1731 public: 1732 CFRefReport(CFRefBug &D, const LangOptions &LOpts, bool GCEnabled, 1733 const SummaryLogTy &Log, ExplodedNode *n, SymbolRef sym, 1734 bool registerVisitor = true) 1735 : BugReport(D, D.getDescription(), n) { 1736 if (registerVisitor) 1737 addVisitor(new CFRefReportVisitor(sym, GCEnabled, Log)); 1738 addGCModeDescription(LOpts, GCEnabled); 1739 } 1740 1741 CFRefReport(CFRefBug &D, const LangOptions &LOpts, bool GCEnabled, 1742 const SummaryLogTy &Log, ExplodedNode *n, SymbolRef sym, 1743 StringRef endText) 1744 : BugReport(D, D.getDescription(), endText, n) { 1745 addVisitor(new CFRefReportVisitor(sym, GCEnabled, Log)); 1746 addGCModeDescription(LOpts, GCEnabled); 1747 } 1748 1749 virtual std::pair<ranges_iterator, ranges_iterator> getRanges() { 1750 const CFRefBug& BugTy = static_cast<CFRefBug&>(getBugType()); 1751 if (!BugTy.isLeak()) 1752 return BugReport::getRanges(); 1753 else 1754 return std::make_pair(ranges_iterator(), ranges_iterator()); 1755 } 1756 }; 1757 1758 class CFRefLeakReport : public CFRefReport { 1759 SourceLocation AllocSite; 1760 const MemRegion* AllocBinding; 1761 1762 public: 1763 CFRefLeakReport(CFRefBug &D, const LangOptions &LOpts, bool GCEnabled, 1764 const SummaryLogTy &Log, ExplodedNode *n, SymbolRef sym, 1765 ExprEngine &Eng); 1766 1767 SourceLocation getLocation() const { return AllocSite; } 1768 }; 1769} // end anonymous namespace 1770 1771void CFRefReport::addGCModeDescription(const LangOptions &LOpts, 1772 bool GCEnabled) { 1773 const char *GCModeDescription = 0; 1774 1775 switch (LOpts.getGCMode()) { 1776 case LangOptions::GCOnly: 1777 assert(GCEnabled); 1778 GCModeDescription = "Code is compiled to only use garbage collection"; 1779 break; 1780 1781 case LangOptions::NonGC: 1782 assert(!GCEnabled); 1783 GCModeDescription = "Code is compiled to use reference counts"; 1784 break; 1785 1786 case LangOptions::HybridGC: 1787 if (GCEnabled) { 1788 GCModeDescription = "Code is compiled to use either garbage collection " 1789 "(GC) or reference counts (non-GC). The bug occurs " 1790 "with GC enabled"; 1791 break; 1792 } else { 1793 GCModeDescription = "Code is compiled to use either garbage collection " 1794 "(GC) or reference counts (non-GC). The bug occurs " 1795 "in non-GC mode"; 1796 break; 1797 } 1798 } 1799 1800 assert(GCModeDescription && "invalid/unknown GC mode"); 1801 addExtraText(GCModeDescription); 1802} 1803 1804// FIXME: This should be a method on SmallVector. 1805static inline bool contains(const SmallVectorImpl<ArgEffect>& V, 1806 ArgEffect X) { 1807 for (SmallVectorImpl<ArgEffect>::const_iterator I=V.begin(), E=V.end(); 1808 I!=E; ++I) 1809 if (*I == X) return true; 1810 1811 return false; 1812} 1813 1814PathDiagnosticPiece *CFRefReportVisitor::VisitNode(const ExplodedNode *N, 1815 const ExplodedNode *PrevN, 1816 BugReporterContext &BRC, 1817 BugReport &BR) { 1818 1819 if (!isa<StmtPoint>(N->getLocation())) 1820 return NULL; 1821 1822 // Check if the type state has changed. 1823 const ProgramState *PrevSt = PrevN->getState(); 1824 const ProgramState *CurrSt = N->getState(); 1825 1826 const RefVal* CurrT = CurrSt->get<RefBindings>(Sym); 1827 if (!CurrT) return NULL; 1828 1829 const RefVal &CurrV = *CurrT; 1830 const RefVal *PrevT = PrevSt->get<RefBindings>(Sym); 1831 1832 // Create a string buffer to constain all the useful things we want 1833 // to tell the user. 1834 std::string sbuf; 1835 llvm::raw_string_ostream os(sbuf); 1836 1837 // This is the allocation site since the previous node had no bindings 1838 // for this symbol. 1839 if (!PrevT) { 1840 const Stmt *S = cast<StmtPoint>(N->getLocation()).getStmt(); 1841 1842 if (const CallExpr *CE = dyn_cast<CallExpr>(S)) { 1843 // Get the name of the callee (if it is available). 1844 SVal X = CurrSt->getSValAsScalarOrLoc(CE->getCallee()); 1845 if (const FunctionDecl *FD = X.getAsFunctionDecl()) 1846 os << "Call to function '" << FD << '\''; 1847 else 1848 os << "function call"; 1849 } 1850 else if (isa<ObjCMessageExpr>(S)) { 1851 os << "Method"; 1852 } else { 1853 os << "Property"; 1854 } 1855 1856 if (CurrV.getObjKind() == RetEffect::CF) { 1857 os << " returns a Core Foundation object with a "; 1858 } 1859 else { 1860 assert (CurrV.getObjKind() == RetEffect::ObjC); 1861 os << " returns an Objective-C object with a "; 1862 } 1863 1864 if (CurrV.isOwned()) { 1865 os << "+1 retain count"; 1866 1867 if (GCEnabled) { 1868 assert(CurrV.getObjKind() == RetEffect::CF); 1869 os << ". " 1870 "Core Foundation objects are not automatically garbage collected."; 1871 } 1872 } 1873 else { 1874 assert (CurrV.isNotOwned()); 1875 os << "+0 retain count"; 1876 } 1877 1878 PathDiagnosticLocation Pos(S, BRC.getSourceManager()); 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 PathDiagnosticPiece *P = new PathDiagnosticEventPiece(Pos, os.str()); 2044 2045 // Add the range by scanning the children of the statement for any bindings 2046 // to Sym. 2047 for (Stmt::const_child_iterator I = S->child_begin(), E = S->child_end(); 2048 I!=E; ++I) 2049 if (const Expr *Exp = dyn_cast_or_null<Expr>(*I)) 2050 if (CurrSt->getSValAsScalarOrLoc(Exp).getAsLocSymbol() == Sym) { 2051 P->addRange(Exp->getSourceRange()); 2052 break; 2053 } 2054 2055 return P; 2056} 2057 2058namespace { 2059 class FindUniqueBinding : 2060 public StoreManager::BindingsHandler { 2061 SymbolRef Sym; 2062 const MemRegion* Binding; 2063 bool First; 2064 2065 public: 2066 FindUniqueBinding(SymbolRef sym) : Sym(sym), Binding(0), First(true) {} 2067 2068 bool HandleBinding(StoreManager& SMgr, Store store, const MemRegion* R, 2069 SVal val) { 2070 2071 SymbolRef SymV = val.getAsSymbol(); 2072 if (!SymV || SymV != Sym) 2073 return true; 2074 2075 if (Binding) { 2076 First = false; 2077 return false; 2078 } 2079 else 2080 Binding = R; 2081 2082 return true; 2083 } 2084 2085 operator bool() { return First && Binding; } 2086 const MemRegion* getRegion() { return Binding; } 2087 }; 2088} 2089 2090static std::pair<const ExplodedNode*,const MemRegion*> 2091GetAllocationSite(ProgramStateManager& StateMgr, const ExplodedNode *N, 2092 SymbolRef Sym) { 2093 2094 // Find both first node that referred to the tracked symbol and the 2095 // memory location that value was store to. 2096 const ExplodedNode *Last = N; 2097 const MemRegion* FirstBinding = 0; 2098 2099 while (N) { 2100 const ProgramState *St = N->getState(); 2101 RefBindings B = St->get<RefBindings>(); 2102 2103 if (!B.lookup(Sym)) 2104 break; 2105 2106 FindUniqueBinding FB(Sym); 2107 StateMgr.iterBindings(St, FB); 2108 if (FB) FirstBinding = FB.getRegion(); 2109 2110 Last = N; 2111 N = N->pred_empty() ? NULL : *(N->pred_begin()); 2112 } 2113 2114 return std::make_pair(Last, FirstBinding); 2115} 2116 2117PathDiagnosticPiece* 2118CFRefReportVisitor::getEndPath(BugReporterContext &BRC, 2119 const ExplodedNode *EndN, 2120 BugReport &BR) { 2121 // Tell the BugReporterContext to report cases when the tracked symbol is 2122 // assigned to different variables, etc. 2123 BRC.addNotableSymbol(Sym); 2124 return BugReporterVisitor::getDefaultEndPath(BRC, EndN, BR); 2125} 2126 2127PathDiagnosticPiece* 2128CFRefLeakReportVisitor::getEndPath(BugReporterContext &BRC, 2129 const ExplodedNode *EndN, 2130 BugReport &BR) { 2131 2132 // Tell the BugReporterContext to report cases when the tracked symbol is 2133 // assigned to different variables, etc. 2134 BRC.addNotableSymbol(Sym); 2135 2136 // We are reporting a leak. Walk up the graph to get to the first node where 2137 // the symbol appeared, and also get the first VarDecl that tracked object 2138 // is stored to. 2139 const ExplodedNode *AllocNode = 0; 2140 const MemRegion* FirstBinding = 0; 2141 2142 llvm::tie(AllocNode, FirstBinding) = 2143 GetAllocationSite(BRC.getStateManager(), EndN, Sym); 2144 2145 SourceManager& SMgr = BRC.getSourceManager(); 2146 2147 // Compute an actual location for the leak. Sometimes a leak doesn't 2148 // occur at an actual statement (e.g., transition between blocks; end 2149 // of function) so we need to walk the graph and compute a real location. 2150 const ExplodedNode *LeakN = EndN; 2151 PathDiagnosticLocation L; 2152 2153 while (LeakN) { 2154 ProgramPoint P = LeakN->getLocation(); 2155 2156 if (const StmtPoint *PS = dyn_cast<StmtPoint>(&P)) { 2157 L = PathDiagnosticLocation(PS->getStmt()->getLocStart(), SMgr); 2158 break; 2159 } 2160 else if (const BlockEdge *BE = dyn_cast<BlockEdge>(&P)) { 2161 if (const Stmt *Term = BE->getSrc()->getTerminator()) { 2162 L = PathDiagnosticLocation(Term->getLocStart(), SMgr); 2163 break; 2164 } 2165 } 2166 2167 LeakN = LeakN->succ_empty() ? 0 : *(LeakN->succ_begin()); 2168 } 2169 2170 if (!L.isValid()) { 2171 const Decl &D = EndN->getCodeDecl(); 2172 L = PathDiagnosticLocation(D.getBodyRBrace(), SMgr); 2173 } 2174 2175 std::string sbuf; 2176 llvm::raw_string_ostream os(sbuf); 2177 2178 os << "Object leaked: "; 2179 2180 if (FirstBinding) { 2181 os << "object allocated and stored into '" 2182 << FirstBinding->getString() << '\''; 2183 } 2184 else 2185 os << "allocated object"; 2186 2187 // Get the retain count. 2188 const RefVal* RV = EndN->getState()->get<RefBindings>(Sym); 2189 2190 if (RV->getKind() == RefVal::ErrorLeakReturned) { 2191 // FIXME: Per comments in rdar://6320065, "create" only applies to CF 2192 // objects. Only "copy", "alloc", "retain" and "new" transfer ownership 2193 // to the caller for NS objects. 2194 const Decl *D = &EndN->getCodeDecl(); 2195 if (const ObjCMethodDecl *MD = dyn_cast<ObjCMethodDecl>(D)) { 2196 os << " is returned from a method whose name ('" 2197 << MD->getSelector().getAsString() 2198 << "') does not start with 'copy', 'mutableCopy', 'alloc' or 'new'." 2199 " This violates the naming convention rules" 2200 " given in the Memory Management Guide for Cocoa"; 2201 } 2202 else { 2203 const FunctionDecl *FD = cast<FunctionDecl>(D); 2204 os << " is return from a function whose name ('" 2205 << FD->getNameAsString() 2206 << "') does not contain 'Copy' or 'Create'. This violates the naming" 2207 " convention rules given the Memory Management Guide for Core" 2208 " Foundation"; 2209 } 2210 } 2211 else if (RV->getKind() == RefVal::ErrorGCLeakReturned) { 2212 ObjCMethodDecl &MD = cast<ObjCMethodDecl>(EndN->getCodeDecl()); 2213 os << " and returned from method '" << MD.getSelector().getAsString() 2214 << "' is potentially leaked when using garbage collection. Callers " 2215 "of this method do not expect a returned object with a +1 retain " 2216 "count since they expect the object to be managed by the garbage " 2217 "collector"; 2218 } 2219 else 2220 os << " is not referenced later in this execution path and has a retain " 2221 "count of +" << RV->getCount(); 2222 2223 return new PathDiagnosticEventPiece(L, os.str()); 2224} 2225 2226CFRefLeakReport::CFRefLeakReport(CFRefBug &D, const LangOptions &LOpts, 2227 bool GCEnabled, const SummaryLogTy &Log, 2228 ExplodedNode *n, SymbolRef sym, 2229 ExprEngine &Eng) 2230: CFRefReport(D, LOpts, GCEnabled, Log, n, sym, false) { 2231 2232 // Most bug reports are cached at the location where they occurred. 2233 // With leaks, we want to unique them by the location where they were 2234 // allocated, and only report a single path. To do this, we need to find 2235 // the allocation site of a piece of tracked memory, which we do via a 2236 // call to GetAllocationSite. This will walk the ExplodedGraph backwards. 2237 // Note that this is *not* the trimmed graph; we are guaranteed, however, 2238 // that all ancestor nodes that represent the allocation site have the 2239 // same SourceLocation. 2240 const ExplodedNode *AllocNode = 0; 2241 2242 llvm::tie(AllocNode, AllocBinding) = // Set AllocBinding. 2243 GetAllocationSite(Eng.getStateManager(), getErrorNode(), sym); 2244 2245 // Get the SourceLocation for the allocation site. 2246 ProgramPoint P = AllocNode->getLocation(); 2247 AllocSite = cast<PostStmt>(P).getStmt()->getLocStart(); 2248 2249 // Fill in the description of the bug. 2250 Description.clear(); 2251 llvm::raw_string_ostream os(Description); 2252 SourceManager& SMgr = Eng.getContext().getSourceManager(); 2253 unsigned AllocLine = SMgr.getExpansionLineNumber(AllocSite); 2254 os << "Potential leak "; 2255 if (GCEnabled) 2256 os << "(when using garbage collection) "; 2257 os << "of an object allocated on line " << AllocLine; 2258 2259 // FIXME: AllocBinding doesn't get populated for RegionStore yet. 2260 if (AllocBinding) 2261 os << " and stored into '" << AllocBinding->getString() << '\''; 2262 2263 addVisitor(new CFRefLeakReportVisitor(sym, GCEnabled, Log)); 2264} 2265 2266//===----------------------------------------------------------------------===// 2267// Main checker logic. 2268//===----------------------------------------------------------------------===// 2269 2270namespace { 2271class RetainCountChecker 2272 : public Checker< check::Bind, 2273 check::DeadSymbols, 2274 check::EndAnalysis, 2275 check::EndPath, 2276 check::PostStmt<BlockExpr>, 2277 check::PostStmt<CastExpr>, 2278 check::PostStmt<CallExpr>, 2279 check::PostStmt<CXXConstructExpr>, 2280 check::PostObjCMessage, 2281 check::PreStmt<ReturnStmt>, 2282 check::RegionChanges, 2283 eval::Assume, 2284 eval::Call > { 2285 mutable llvm::OwningPtr<CFRefBug> useAfterRelease, releaseNotOwned; 2286 mutable llvm::OwningPtr<CFRefBug> deallocGC, deallocNotOwned; 2287 mutable llvm::OwningPtr<CFRefBug> overAutorelease, returnNotOwnedForOwned; 2288 mutable llvm::OwningPtr<CFRefBug> leakWithinFunction, leakAtReturn; 2289 mutable llvm::OwningPtr<CFRefBug> leakWithinFunctionGC, leakAtReturnGC; 2290 2291 typedef llvm::DenseMap<SymbolRef, const SimpleProgramPointTag *> SymbolTagMap; 2292 2293 // This map is only used to ensure proper deletion of any allocated tags. 2294 mutable SymbolTagMap DeadSymbolTags; 2295 2296 mutable llvm::OwningPtr<RetainSummaryManager> Summaries; 2297 mutable llvm::OwningPtr<RetainSummaryManager> SummariesGC; 2298 2299 mutable ARCounts::Factory ARCountFactory; 2300 2301 mutable SummaryLogTy SummaryLog; 2302 mutable bool ShouldResetSummaryLog; 2303 2304public: 2305 RetainCountChecker() : ShouldResetSummaryLog(false) {} 2306 2307 virtual ~RetainCountChecker() { 2308 DeleteContainerSeconds(DeadSymbolTags); 2309 } 2310 2311 void checkEndAnalysis(ExplodedGraph &G, BugReporter &BR, 2312 ExprEngine &Eng) const { 2313 // FIXME: This is a hack to make sure the summary log gets cleared between 2314 // analyses of different code bodies. 2315 // 2316 // Why is this necessary? Because a checker's lifetime is tied to a 2317 // translation unit, but an ExplodedGraph's lifetime is just a code body. 2318 // Once in a blue moon, a new ExplodedNode will have the same address as an 2319 // old one with an associated summary, and the bug report visitor gets very 2320 // confused. (To make things worse, the summary lifetime is currently also 2321 // tied to a code body, so we get a crash instead of incorrect results.) 2322 // 2323 // Why is this a bad solution? Because if the lifetime of the ExplodedGraph 2324 // changes, things will start going wrong again. Really the lifetime of this 2325 // log needs to be tied to either the specific nodes in it or the entire 2326 // ExplodedGraph, not to a specific part of the code being analyzed. 2327 // 2328 // (Also, having stateful local data means that the same checker can't be 2329 // used from multiple threads, but a lot of checkers have incorrect 2330 // assumptions about that anyway. So that wasn't a priority at the time of 2331 // this fix.) 2332 // 2333 // This happens at the end of analysis, but bug reports are emitted /after/ 2334 // this point. So we can't just clear the summary log now. Instead, we mark 2335 // that the next time we access the summary log, it should be cleared. 2336 2337 // If we never reset the summary log during /this/ code body analysis, 2338 // there were no new summaries. There might still have been summaries from 2339 // the /last/ analysis, so clear them out to make sure the bug report 2340 // visitors don't get confused. 2341 if (ShouldResetSummaryLog) 2342 SummaryLog.clear(); 2343 2344 ShouldResetSummaryLog = !SummaryLog.empty(); 2345 } 2346 2347 CFRefBug *getLeakWithinFunctionBug(const LangOptions &LOpts, 2348 bool GCEnabled) const { 2349 if (GCEnabled) { 2350 if (!leakWithinFunctionGC) 2351 leakWithinFunctionGC.reset(new LeakWithinFunction("Leak of object when " 2352 "using garbage " 2353 "collection")); 2354 return leakWithinFunctionGC.get(); 2355 } else { 2356 if (!leakWithinFunction) { 2357 if (LOpts.getGCMode() == LangOptions::HybridGC) { 2358 leakWithinFunction.reset(new LeakWithinFunction("Leak of object when " 2359 "not using garbage " 2360 "collection (GC) in " 2361 "dual GC/non-GC " 2362 "code")); 2363 } else { 2364 leakWithinFunction.reset(new LeakWithinFunction("Leak")); 2365 } 2366 } 2367 return leakWithinFunction.get(); 2368 } 2369 } 2370 2371 CFRefBug *getLeakAtReturnBug(const LangOptions &LOpts, bool GCEnabled) const { 2372 if (GCEnabled) { 2373 if (!leakAtReturnGC) 2374 leakAtReturnGC.reset(new LeakAtReturn("Leak of returned object when " 2375 "using garbage collection")); 2376 return leakAtReturnGC.get(); 2377 } else { 2378 if (!leakAtReturn) { 2379 if (LOpts.getGCMode() == LangOptions::HybridGC) { 2380 leakAtReturn.reset(new LeakAtReturn("Leak of returned object when " 2381 "not using garbage collection " 2382 "(GC) in dual GC/non-GC code")); 2383 } else { 2384 leakAtReturn.reset(new LeakAtReturn("Leak of returned object")); 2385 } 2386 } 2387 return leakAtReturn.get(); 2388 } 2389 } 2390 2391 RetainSummaryManager &getSummaryManager(ASTContext &Ctx, 2392 bool GCEnabled) const { 2393 // FIXME: We don't support ARC being turned on and off during one analysis. 2394 // (nor, for that matter, do we support changing ASTContexts) 2395 bool ARCEnabled = (bool)Ctx.getLangOptions().ObjCAutoRefCount; 2396 if (GCEnabled) { 2397 if (!SummariesGC) 2398 SummariesGC.reset(new RetainSummaryManager(Ctx, true, ARCEnabled)); 2399 else 2400 assert(SummariesGC->isARCEnabled() == ARCEnabled); 2401 return *SummariesGC; 2402 } else { 2403 if (!Summaries) 2404 Summaries.reset(new RetainSummaryManager(Ctx, false, ARCEnabled)); 2405 else 2406 assert(Summaries->isARCEnabled() == ARCEnabled); 2407 return *Summaries; 2408 } 2409 } 2410 2411 RetainSummaryManager &getSummaryManager(CheckerContext &C) const { 2412 return getSummaryManager(C.getASTContext(), C.isObjCGCEnabled()); 2413 } 2414 2415 void printState(raw_ostream &Out, const ProgramState *State, 2416 const char *NL, const char *Sep) const; 2417 2418 void checkBind(SVal loc, SVal val, CheckerContext &C) const; 2419 void checkPostStmt(const BlockExpr *BE, CheckerContext &C) const; 2420 void checkPostStmt(const CastExpr *CE, CheckerContext &C) const; 2421 2422 void checkPostStmt(const CallExpr *CE, CheckerContext &C) const; 2423 void checkPostStmt(const CXXConstructExpr *CE, CheckerContext &C) const; 2424 void checkPostObjCMessage(const ObjCMessage &Msg, CheckerContext &C) const; 2425 void checkSummary(const RetainSummary &Summ, const CallOrObjCMessage &Call, 2426 CheckerContext &C) const; 2427 2428 bool evalCall(const CallExpr *CE, CheckerContext &C) const; 2429 2430 const ProgramState *evalAssume(const ProgramState *state, SVal Cond, 2431 bool Assumption) const; 2432 2433 const ProgramState * 2434 checkRegionChanges(const ProgramState *state, 2435 const StoreManager::InvalidatedSymbols *invalidated, 2436 ArrayRef<const MemRegion *> ExplicitRegions, 2437 ArrayRef<const MemRegion *> Regions) const; 2438 2439 bool wantsRegionChangeUpdate(const ProgramState *state) const { 2440 return true; 2441 } 2442 2443 void checkPreStmt(const ReturnStmt *S, CheckerContext &C) const; 2444 void checkReturnWithRetEffect(const ReturnStmt *S, CheckerContext &C, 2445 ExplodedNode *Pred, RetEffect RE, RefVal X, 2446 SymbolRef Sym, const ProgramState *state) const; 2447 2448 void checkDeadSymbols(SymbolReaper &SymReaper, CheckerContext &C) const; 2449 void checkEndPath(EndOfFunctionNodeBuilder &Builder, ExprEngine &Eng) const; 2450 2451 const ProgramState *updateSymbol(const ProgramState *state, SymbolRef sym, 2452 RefVal V, ArgEffect E, RefVal::Kind &hasErr, 2453 CheckerContext &C) const; 2454 2455 void processNonLeakError(const ProgramState *St, SourceRange ErrorRange, 2456 RefVal::Kind ErrorKind, SymbolRef Sym, 2457 CheckerContext &C) const; 2458 2459 const ProgramPointTag *getDeadSymbolTag(SymbolRef sym) const; 2460 2461 const ProgramState *handleSymbolDeath(const ProgramState *state, 2462 SymbolRef sid, RefVal V, 2463 SmallVectorImpl<SymbolRef> &Leaked) const; 2464 2465 std::pair<ExplodedNode *, const ProgramState *> 2466 handleAutoreleaseCounts(const ProgramState *state, 2467 GenericNodeBuilderRefCount Bd, ExplodedNode *Pred, 2468 ExprEngine &Eng, SymbolRef Sym, RefVal V) const; 2469 2470 ExplodedNode *processLeaks(const ProgramState *state, 2471 SmallVectorImpl<SymbolRef> &Leaked, 2472 GenericNodeBuilderRefCount &Builder, 2473 ExprEngine &Eng, 2474 ExplodedNode *Pred = 0) const; 2475}; 2476} // end anonymous namespace 2477 2478namespace { 2479class StopTrackingCallback : public SymbolVisitor { 2480 const ProgramState *state; 2481public: 2482 StopTrackingCallback(const ProgramState *st) : state(st) {} 2483 const ProgramState *getState() const { return state; } 2484 2485 bool VisitSymbol(SymbolRef sym) { 2486 state = state->remove<RefBindings>(sym); 2487 return true; 2488 } 2489}; 2490} // end anonymous namespace 2491 2492//===----------------------------------------------------------------------===// 2493// Handle statements that may have an effect on refcounts. 2494//===----------------------------------------------------------------------===// 2495 2496void RetainCountChecker::checkPostStmt(const BlockExpr *BE, 2497 CheckerContext &C) const { 2498 2499 // Scan the BlockDecRefExprs for any object the retain count checker 2500 // may be tracking. 2501 if (!BE->getBlockDecl()->hasCaptures()) 2502 return; 2503 2504 const ProgramState *state = C.getState(); 2505 const BlockDataRegion *R = 2506 cast<BlockDataRegion>(state->getSVal(BE).getAsRegion()); 2507 2508 BlockDataRegion::referenced_vars_iterator I = R->referenced_vars_begin(), 2509 E = R->referenced_vars_end(); 2510 2511 if (I == E) 2512 return; 2513 2514 // FIXME: For now we invalidate the tracking of all symbols passed to blocks 2515 // via captured variables, even though captured variables result in a copy 2516 // and in implicit increment/decrement of a retain count. 2517 SmallVector<const MemRegion*, 10> Regions; 2518 const LocationContext *LC = C.getPredecessor()->getLocationContext(); 2519 MemRegionManager &MemMgr = C.getSValBuilder().getRegionManager(); 2520 2521 for ( ; I != E; ++I) { 2522 const VarRegion *VR = *I; 2523 if (VR->getSuperRegion() == R) { 2524 VR = MemMgr.getVarRegion(VR->getDecl(), LC); 2525 } 2526 Regions.push_back(VR); 2527 } 2528 2529 state = 2530 state->scanReachableSymbols<StopTrackingCallback>(Regions.data(), 2531 Regions.data() + Regions.size()).getState(); 2532 C.addTransition(state); 2533} 2534 2535void RetainCountChecker::checkPostStmt(const CastExpr *CE, 2536 CheckerContext &C) const { 2537 const ObjCBridgedCastExpr *BE = dyn_cast<ObjCBridgedCastExpr>(CE); 2538 if (!BE) 2539 return; 2540 2541 ArgEffect AE = IncRef; 2542 2543 switch (BE->getBridgeKind()) { 2544 case clang::OBC_Bridge: 2545 // Do nothing. 2546 return; 2547 case clang::OBC_BridgeRetained: 2548 AE = IncRef; 2549 break; 2550 case clang::OBC_BridgeTransfer: 2551 AE = DecRefBridgedTransfered; 2552 break; 2553 } 2554 2555 const ProgramState *state = C.getState(); 2556 SymbolRef Sym = state->getSVal(CE).getAsLocSymbol(); 2557 if (!Sym) 2558 return; 2559 const RefVal* T = state->get<RefBindings>(Sym); 2560 if (!T) 2561 return; 2562 2563 RefVal::Kind hasErr = (RefVal::Kind) 0; 2564 state = updateSymbol(state, Sym, *T, AE, hasErr, C); 2565 2566 if (hasErr) { 2567 // FIXME: If we get an error during a bridge cast, should we report it? 2568 // Should we assert that there is no error? 2569 return; 2570 } 2571 2572 C.generateNode(state); 2573} 2574 2575void RetainCountChecker::checkPostStmt(const CallExpr *CE, 2576 CheckerContext &C) const { 2577 // Get the callee. 2578 const ProgramState *state = C.getState(); 2579 const Expr *Callee = CE->getCallee(); 2580 SVal L = state->getSVal(Callee); 2581 2582 RetainSummaryManager &Summaries = getSummaryManager(C); 2583 RetainSummary *Summ = 0; 2584 2585 // FIXME: Better support for blocks. For now we stop tracking anything 2586 // that is passed to blocks. 2587 // FIXME: Need to handle variables that are "captured" by the block. 2588 if (dyn_cast_or_null<BlockDataRegion>(L.getAsRegion())) { 2589 Summ = Summaries.getPersistentStopSummary(); 2590 } else if (const FunctionDecl *FD = L.getAsFunctionDecl()) { 2591 Summ = Summaries.getSummary(FD); 2592 } else if (const CXXMemberCallExpr *me = dyn_cast<CXXMemberCallExpr>(CE)) { 2593 if (const CXXMethodDecl *MD = me->getMethodDecl()) 2594 Summ = Summaries.getSummary(MD); 2595 } 2596 2597 // If we didn't get a summary, this function doesn't affect retain counts. 2598 if (!Summ) 2599 return; 2600 2601 checkSummary(*Summ, CallOrObjCMessage(CE, state), C); 2602} 2603 2604void RetainCountChecker::checkPostStmt(const CXXConstructExpr *CE, 2605 CheckerContext &C) const { 2606 const CXXConstructorDecl *Ctor = CE->getConstructor(); 2607 if (!Ctor) 2608 return; 2609 2610 RetainSummaryManager &Summaries = getSummaryManager(C); 2611 RetainSummary *Summ = Summaries.getSummary(Ctor); 2612 2613 // If we didn't get a summary, this constructor doesn't affect retain counts. 2614 if (!Summ) 2615 return; 2616 2617 const ProgramState *state = C.getState(); 2618 checkSummary(*Summ, CallOrObjCMessage(CE, state), C); 2619} 2620 2621void RetainCountChecker::checkPostObjCMessage(const ObjCMessage &Msg, 2622 CheckerContext &C) const { 2623 const ProgramState *state = C.getState(); 2624 ExplodedNode *Pred = C.getPredecessor(); 2625 2626 RetainSummaryManager &Summaries = getSummaryManager(C); 2627 2628 RetainSummary *Summ; 2629 if (Msg.isInstanceMessage()) { 2630 const LocationContext *LC = Pred->getLocationContext(); 2631 Summ = Summaries.getInstanceMethodSummary(Msg, state, LC); 2632 } else { 2633 Summ = Summaries.getClassMethodSummary(Msg); 2634 } 2635 2636 // If we didn't get a summary, this message doesn't affect retain counts. 2637 if (!Summ) 2638 return; 2639 2640 checkSummary(*Summ, CallOrObjCMessage(Msg, state), C); 2641} 2642 2643/// GetReturnType - Used to get the return type of a message expression or 2644/// function call with the intention of affixing that type to a tracked symbol. 2645/// While the the return type can be queried directly from RetEx, when 2646/// invoking class methods we augment to the return type to be that of 2647/// a pointer to the class (as opposed it just being id). 2648// FIXME: We may be able to do this with related result types instead. 2649// This function is probably overestimating. 2650static QualType GetReturnType(const Expr *RetE, ASTContext &Ctx) { 2651 QualType RetTy = RetE->getType(); 2652 // If RetE is not a message expression just return its type. 2653 // If RetE is a message expression, return its types if it is something 2654 /// more specific than id. 2655 if (const ObjCMessageExpr *ME = dyn_cast<ObjCMessageExpr>(RetE)) 2656 if (const ObjCObjectPointerType *PT = RetTy->getAs<ObjCObjectPointerType>()) 2657 if (PT->isObjCQualifiedIdType() || PT->isObjCIdType() || 2658 PT->isObjCClassType()) { 2659 // At this point we know the return type of the message expression is 2660 // id, id<...>, or Class. If we have an ObjCInterfaceDecl, we know this 2661 // is a call to a class method whose type we can resolve. In such 2662 // cases, promote the return type to XXX* (where XXX is the class). 2663 const ObjCInterfaceDecl *D = ME->getReceiverInterface(); 2664 return !D ? RetTy : 2665 Ctx.getObjCObjectPointerType(Ctx.getObjCInterfaceType(D)); 2666 } 2667 2668 return RetTy; 2669} 2670 2671void RetainCountChecker::checkSummary(const RetainSummary &Summ, 2672 const CallOrObjCMessage &CallOrMsg, 2673 CheckerContext &C) const { 2674 const ProgramState *state = C.getState(); 2675 2676 // Evaluate the effect of the arguments. 2677 RefVal::Kind hasErr = (RefVal::Kind) 0; 2678 SourceRange ErrorRange; 2679 SymbolRef ErrorSym = 0; 2680 2681 for (unsigned idx = 0, e = CallOrMsg.getNumArgs(); idx != e; ++idx) { 2682 SVal V = CallOrMsg.getArgSVal(idx); 2683 2684 if (SymbolRef Sym = V.getAsLocSymbol()) { 2685 if (RefBindings::data_type *T = state->get<RefBindings>(Sym)) { 2686 state = updateSymbol(state, Sym, *T, Summ.getArg(idx), hasErr, C); 2687 if (hasErr) { 2688 ErrorRange = CallOrMsg.getArgSourceRange(idx); 2689 ErrorSym = Sym; 2690 break; 2691 } 2692 } 2693 } 2694 } 2695 2696 // Evaluate the effect on the message receiver. 2697 bool ReceiverIsTracked = false; 2698 if (!hasErr && CallOrMsg.isObjCMessage()) { 2699 const LocationContext *LC = C.getPredecessor()->getLocationContext(); 2700 SVal Receiver = CallOrMsg.getInstanceMessageReceiver(LC); 2701 if (SymbolRef Sym = Receiver.getAsLocSymbol()) { 2702 if (const RefVal *T = state->get<RefBindings>(Sym)) { 2703 ReceiverIsTracked = true; 2704 state = updateSymbol(state, Sym, *T, Summ.getReceiverEffect(), 2705 hasErr, C); 2706 if (hasErr) { 2707 ErrorRange = CallOrMsg.getReceiverSourceRange(); 2708 ErrorSym = Sym; 2709 } 2710 } 2711 } 2712 } 2713 2714 // Process any errors. 2715 if (hasErr) { 2716 processNonLeakError(state, ErrorRange, hasErr, ErrorSym, C); 2717 return; 2718 } 2719 2720 // Consult the summary for the return value. 2721 RetEffect RE = Summ.getRetEffect(); 2722 2723 if (RE.getKind() == RetEffect::OwnedWhenTrackedReceiver) { 2724 if (ReceiverIsTracked) 2725 RE = getSummaryManager(C).getObjAllocRetEffect(); 2726 else 2727 RE = RetEffect::MakeNoRet(); 2728 } 2729 2730 switch (RE.getKind()) { 2731 default: 2732 llvm_unreachable("Unhandled RetEffect."); break; 2733 2734 case RetEffect::NoRet: 2735 // No work necessary. 2736 break; 2737 2738 case RetEffect::OwnedAllocatedSymbol: 2739 case RetEffect::OwnedSymbol: { 2740 SymbolRef Sym = state->getSVal(CallOrMsg.getOriginExpr()).getAsSymbol(); 2741 if (!Sym) 2742 break; 2743 2744 // Use the result type from callOrMsg as it automatically adjusts 2745 // for methods/functions that return references. 2746 QualType ResultTy = CallOrMsg.getResultType(C.getASTContext()); 2747 state = state->set<RefBindings>(Sym, RefVal::makeOwned(RE.getObjKind(), 2748 ResultTy)); 2749 2750 // FIXME: Add a flag to the checker where allocations are assumed to 2751 // *not* fail. (The code below is out-of-date, though.) 2752#if 0 2753 if (RE.getKind() == RetEffect::OwnedAllocatedSymbol) { 2754 bool isFeasible; 2755 state = state.assume(loc::SymbolVal(Sym), true, isFeasible); 2756 assert(isFeasible && "Cannot assume fresh symbol is non-null."); 2757 } 2758#endif 2759 2760 break; 2761 } 2762 2763 case RetEffect::GCNotOwnedSymbol: 2764 case RetEffect::ARCNotOwnedSymbol: 2765 case RetEffect::NotOwnedSymbol: { 2766 const Expr *Ex = CallOrMsg.getOriginExpr(); 2767 SymbolRef Sym = state->getSVal(Ex).getAsSymbol(); 2768 if (!Sym) 2769 break; 2770 2771 // Use GetReturnType in order to give [NSFoo alloc] the type NSFoo *. 2772 QualType ResultTy = GetReturnType(Ex, C.getASTContext()); 2773 state = state->set<RefBindings>(Sym, RefVal::makeNotOwned(RE.getObjKind(), 2774 ResultTy)); 2775 break; 2776 } 2777 } 2778 2779 // This check is actually necessary; otherwise the statement builder thinks 2780 // we've hit a previously-found path. 2781 // Normally addTransition takes care of this, but we want the node pointer. 2782 ExplodedNode *NewNode; 2783 if (state == C.getState()) { 2784 NewNode = C.getPredecessor(); 2785 } else { 2786 NewNode = C.generateNode(state); 2787 } 2788 2789 // Annotate the node with summary we used. 2790 if (NewNode) { 2791 // FIXME: This is ugly. See checkEndAnalysis for why it's necessary. 2792 if (ShouldResetSummaryLog) { 2793 SummaryLog.clear(); 2794 ShouldResetSummaryLog = false; 2795 } 2796 SummaryLog[NewNode] = &Summ; 2797 } 2798} 2799 2800 2801const ProgramState * 2802RetainCountChecker::updateSymbol(const ProgramState *state, SymbolRef sym, 2803 RefVal V, ArgEffect E, RefVal::Kind &hasErr, 2804 CheckerContext &C) const { 2805 // In GC mode [... release] and [... retain] do nothing. 2806 // In ARC mode they shouldn't exist at all, but we just ignore them. 2807 bool IgnoreRetainMsg = C.isObjCGCEnabled(); 2808 if (!IgnoreRetainMsg) 2809 IgnoreRetainMsg = (bool)C.getASTContext().getLangOptions().ObjCAutoRefCount; 2810 2811 switch (E) { 2812 default: break; 2813 case IncRefMsg: E = IgnoreRetainMsg ? DoNothing : IncRef; break; 2814 case DecRefMsg: E = IgnoreRetainMsg ? DoNothing : DecRef; break; 2815 case MakeCollectable: E = C.isObjCGCEnabled() ? DecRef : DoNothing; break; 2816 case NewAutoreleasePool: E = C.isObjCGCEnabled() ? DoNothing : 2817 NewAutoreleasePool; break; 2818 } 2819 2820 // Handle all use-after-releases. 2821 if (!C.isObjCGCEnabled() && V.getKind() == RefVal::Released) { 2822 V = V ^ RefVal::ErrorUseAfterRelease; 2823 hasErr = V.getKind(); 2824 return state->set<RefBindings>(sym, V); 2825 } 2826 2827 switch (E) { 2828 case DecRefMsg: 2829 case IncRefMsg: 2830 case MakeCollectable: 2831 llvm_unreachable("DecRefMsg/IncRefMsg/MakeCollectable already converted"); 2832 return state; 2833 2834 case Dealloc: 2835 // Any use of -dealloc in GC is *bad*. 2836 if (C.isObjCGCEnabled()) { 2837 V = V ^ RefVal::ErrorDeallocGC; 2838 hasErr = V.getKind(); 2839 break; 2840 } 2841 2842 switch (V.getKind()) { 2843 default: 2844 llvm_unreachable("Invalid RefVal state for an explicit dealloc."); 2845 break; 2846 case RefVal::Owned: 2847 // The object immediately transitions to the released state. 2848 V = V ^ RefVal::Released; 2849 V.clearCounts(); 2850 return state->set<RefBindings>(sym, V); 2851 case RefVal::NotOwned: 2852 V = V ^ RefVal::ErrorDeallocNotOwned; 2853 hasErr = V.getKind(); 2854 break; 2855 } 2856 break; 2857 2858 case NewAutoreleasePool: 2859 assert(!C.isObjCGCEnabled()); 2860 return state->add<AutoreleaseStack>(sym); 2861 2862 case MayEscape: 2863 if (V.getKind() == RefVal::Owned) { 2864 V = V ^ RefVal::NotOwned; 2865 break; 2866 } 2867 2868 // Fall-through. 2869 2870 case DoNothing: 2871 return state; 2872 2873 case Autorelease: 2874 if (C.isObjCGCEnabled()) 2875 return state; 2876 2877 // Update the autorelease counts. 2878 state = SendAutorelease(state, ARCountFactory, sym); 2879 V = V.autorelease(); 2880 break; 2881 2882 case StopTracking: 2883 return state->remove<RefBindings>(sym); 2884 2885 case IncRef: 2886 switch (V.getKind()) { 2887 default: 2888 llvm_unreachable("Invalid RefVal state for a retain."); 2889 break; 2890 case RefVal::Owned: 2891 case RefVal::NotOwned: 2892 V = V + 1; 2893 break; 2894 case RefVal::Released: 2895 // Non-GC cases are handled above. 2896 assert(C.isObjCGCEnabled()); 2897 V = (V ^ RefVal::Owned) + 1; 2898 break; 2899 } 2900 break; 2901 2902 case SelfOwn: 2903 V = V ^ RefVal::NotOwned; 2904 // Fall-through. 2905 case DecRef: 2906 case DecRefBridgedTransfered: 2907 switch (V.getKind()) { 2908 default: 2909 // case 'RefVal::Released' handled above. 2910 llvm_unreachable("Invalid RefVal state for a release."); 2911 break; 2912 2913 case RefVal::Owned: 2914 assert(V.getCount() > 0); 2915 if (V.getCount() == 1) 2916 V = V ^ (E == DecRefBridgedTransfered ? 2917 RefVal::NotOwned : RefVal::Released); 2918 V = V - 1; 2919 break; 2920 2921 case RefVal::NotOwned: 2922 if (V.getCount() > 0) 2923 V = V - 1; 2924 else { 2925 V = V ^ RefVal::ErrorReleaseNotOwned; 2926 hasErr = V.getKind(); 2927 } 2928 break; 2929 2930 case RefVal::Released: 2931 // Non-GC cases are handled above. 2932 assert(C.isObjCGCEnabled()); 2933 V = V ^ RefVal::ErrorUseAfterRelease; 2934 hasErr = V.getKind(); 2935 break; 2936 } 2937 break; 2938 } 2939 return state->set<RefBindings>(sym, V); 2940} 2941 2942void RetainCountChecker::processNonLeakError(const ProgramState *St, 2943 SourceRange ErrorRange, 2944 RefVal::Kind ErrorKind, 2945 SymbolRef Sym, 2946 CheckerContext &C) const { 2947 ExplodedNode *N = C.generateSink(St); 2948 if (!N) 2949 return; 2950 2951 CFRefBug *BT; 2952 switch (ErrorKind) { 2953 default: 2954 llvm_unreachable("Unhandled error."); 2955 return; 2956 case RefVal::ErrorUseAfterRelease: 2957 if (!useAfterRelease) 2958 useAfterRelease.reset(new UseAfterRelease()); 2959 BT = &*useAfterRelease; 2960 break; 2961 case RefVal::ErrorReleaseNotOwned: 2962 if (!releaseNotOwned) 2963 releaseNotOwned.reset(new BadRelease()); 2964 BT = &*releaseNotOwned; 2965 break; 2966 case RefVal::ErrorDeallocGC: 2967 if (!deallocGC) 2968 deallocGC.reset(new DeallocGC()); 2969 BT = &*deallocGC; 2970 break; 2971 case RefVal::ErrorDeallocNotOwned: 2972 if (!deallocNotOwned) 2973 deallocNotOwned.reset(new DeallocNotOwned()); 2974 BT = &*deallocNotOwned; 2975 break; 2976 } 2977 2978 assert(BT); 2979 CFRefReport *report = new CFRefReport(*BT, C.getASTContext().getLangOptions(), 2980 C.isObjCGCEnabled(), SummaryLog, 2981 N, Sym); 2982 report->addRange(ErrorRange); 2983 C.EmitReport(report); 2984} 2985 2986//===----------------------------------------------------------------------===// 2987// Handle the return values of retain-count-related functions. 2988//===----------------------------------------------------------------------===// 2989 2990bool RetainCountChecker::evalCall(const CallExpr *CE, CheckerContext &C) const { 2991 // Get the callee. We're only interested in simple C functions. 2992 const ProgramState *state = C.getState(); 2993 const Expr *Callee = CE->getCallee(); 2994 SVal L = state->getSVal(Callee); 2995 2996 const FunctionDecl *FD = L.getAsFunctionDecl(); 2997 if (!FD) 2998 return false; 2999 3000 IdentifierInfo *II = FD->getIdentifier(); 3001 if (!II) 3002 return false; 3003 3004 // For now, we're only handling the functions that return aliases of their 3005 // arguments: CFRetain and CFMakeCollectable (and their families). 3006 // Eventually we should add other functions we can model entirely, 3007 // such as CFRelease, which don't invalidate their arguments or globals. 3008 if (CE->getNumArgs() != 1) 3009 return false; 3010 3011 // Get the name of the function. 3012 StringRef FName = II->getName(); 3013 FName = FName.substr(FName.find_first_not_of('_')); 3014 3015 // See if it's one of the specific functions we know how to eval. 3016 bool canEval = false; 3017 3018 QualType ResultTy = FD->getResultType(); 3019 if (ResultTy->isObjCIdType()) { 3020 // Handle: id NSMakeCollectable(CFTypeRef) 3021 canEval = II->isStr("NSMakeCollectable"); 3022 } else if (ResultTy->isPointerType()) { 3023 // Handle: (CF|CG)Retain 3024 // CFMakeCollectable 3025 // It's okay to be a little sloppy here (CGMakeCollectable doesn't exist). 3026 if (cocoa::isRefType(ResultTy, "CF", FName) || 3027 cocoa::isRefType(ResultTy, "CG", FName)) { 3028 canEval = isRetain(FD, FName) || isMakeCollectable(FD, FName); 3029 } 3030 } 3031 3032 if (!canEval) 3033 return false; 3034 3035 // Bind the return value. 3036 SVal RetVal = state->getSVal(CE->getArg(0)); 3037 if (RetVal.isUnknown()) { 3038 // If the receiver is unknown, conjure a return value. 3039 SValBuilder &SVB = C.getSValBuilder(); 3040 unsigned Count = C.getNodeBuilder().getCurrentBlockCount(); 3041 SVal RetVal = SVB.getConjuredSymbolVal(0, CE, ResultTy, Count); 3042 } 3043 state = state->BindExpr(CE, RetVal, false); 3044 3045 // FIXME: This should not be necessary, but otherwise the argument seems to be 3046 // considered alive during the next statement. 3047 if (const MemRegion *ArgRegion = RetVal.getAsRegion()) { 3048 // Save the refcount status of the argument. 3049 SymbolRef Sym = RetVal.getAsLocSymbol(); 3050 RefBindings::data_type *Binding = 0; 3051 if (Sym) 3052 Binding = state->get<RefBindings>(Sym); 3053 3054 // Invalidate the argument region. 3055 unsigned Count = C.getNodeBuilder().getCurrentBlockCount(); 3056 state = state->invalidateRegions(ArgRegion, CE, Count); 3057 3058 // Restore the refcount status of the argument. 3059 if (Binding) 3060 state = state->set<RefBindings>(Sym, *Binding); 3061 } 3062 3063 C.addTransition(state); 3064 return true; 3065} 3066 3067//===----------------------------------------------------------------------===// 3068// Handle return statements. 3069//===----------------------------------------------------------------------===// 3070 3071void RetainCountChecker::checkPreStmt(const ReturnStmt *S, 3072 CheckerContext &C) const { 3073 const Expr *RetE = S->getRetValue(); 3074 if (!RetE) 3075 return; 3076 3077 const ProgramState *state = C.getState(); 3078 SymbolRef Sym = state->getSValAsScalarOrLoc(RetE).getAsLocSymbol(); 3079 if (!Sym) 3080 return; 3081 3082 // Get the reference count binding (if any). 3083 const RefVal *T = state->get<RefBindings>(Sym); 3084 if (!T) 3085 return; 3086 3087 // Change the reference count. 3088 RefVal X = *T; 3089 3090 switch (X.getKind()) { 3091 case RefVal::Owned: { 3092 unsigned cnt = X.getCount(); 3093 assert(cnt > 0); 3094 X.setCount(cnt - 1); 3095 X = X ^ RefVal::ReturnedOwned; 3096 break; 3097 } 3098 3099 case RefVal::NotOwned: { 3100 unsigned cnt = X.getCount(); 3101 if (cnt) { 3102 X.setCount(cnt - 1); 3103 X = X ^ RefVal::ReturnedOwned; 3104 } 3105 else { 3106 X = X ^ RefVal::ReturnedNotOwned; 3107 } 3108 break; 3109 } 3110 3111 default: 3112 return; 3113 } 3114 3115 // Update the binding. 3116 state = state->set<RefBindings>(Sym, X); 3117 ExplodedNode *Pred = C.generateNode(state); 3118 3119 // At this point we have updated the state properly. 3120 // Everything after this is merely checking to see if the return value has 3121 // been over- or under-retained. 3122 3123 // Did we cache out? 3124 if (!Pred) 3125 return; 3126 3127 // Update the autorelease counts. 3128 static SimpleProgramPointTag 3129 AutoreleaseTag("RetainCountChecker : Autorelease"); 3130 GenericNodeBuilderRefCount Bd(C.getNodeBuilder(), S, &AutoreleaseTag); 3131 llvm::tie(Pred, state) = handleAutoreleaseCounts(state, Bd, Pred, 3132 C.getEngine(), Sym, X); 3133 3134 // Did we cache out? 3135 if (!Pred) 3136 return; 3137 3138 // Get the updated binding. 3139 T = state->get<RefBindings>(Sym); 3140 assert(T); 3141 X = *T; 3142 3143 // Consult the summary of the enclosing method. 3144 RetainSummaryManager &Summaries = getSummaryManager(C); 3145 const Decl *CD = &Pred->getCodeDecl(); 3146 3147 if (const ObjCMethodDecl *MD = dyn_cast<ObjCMethodDecl>(CD)) { 3148 // Unlike regular functions, /all/ ObjC methods are assumed to always 3149 // follow Cocoa retain-count conventions, not just those with special 3150 // names or attributes. 3151 const RetainSummary *Summ = Summaries.getMethodSummary(MD); 3152 RetEffect RE = Summ ? Summ->getRetEffect() : RetEffect::MakeNoRet(); 3153 checkReturnWithRetEffect(S, C, Pred, RE, X, Sym, state); 3154 } 3155 3156 if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(CD)) { 3157 if (!isa<CXXMethodDecl>(FD)) 3158 if (const RetainSummary *Summ = Summaries.getSummary(FD)) 3159 checkReturnWithRetEffect(S, C, Pred, Summ->getRetEffect(), X, 3160 Sym, state); 3161 } 3162} 3163 3164void RetainCountChecker::checkReturnWithRetEffect(const ReturnStmt *S, 3165 CheckerContext &C, 3166 ExplodedNode *Pred, 3167 RetEffect RE, RefVal X, 3168 SymbolRef Sym, 3169 const ProgramState *state) const { 3170 // Any leaks or other errors? 3171 if (X.isReturnedOwned() && X.getCount() == 0) { 3172 if (RE.getKind() != RetEffect::NoRet) { 3173 bool hasError = false; 3174 if (C.isObjCGCEnabled() && RE.getObjKind() == RetEffect::ObjC) { 3175 // Things are more complicated with garbage collection. If the 3176 // returned object is suppose to be an Objective-C object, we have 3177 // a leak (as the caller expects a GC'ed object) because no 3178 // method should return ownership unless it returns a CF object. 3179 hasError = true; 3180 X = X ^ RefVal::ErrorGCLeakReturned; 3181 } 3182 else if (!RE.isOwned()) { 3183 // Either we are using GC and the returned object is a CF type 3184 // or we aren't using GC. In either case, we expect that the 3185 // enclosing method is expected to return ownership. 3186 hasError = true; 3187 X = X ^ RefVal::ErrorLeakReturned; 3188 } 3189 3190 if (hasError) { 3191 // Generate an error node. 3192 state = state->set<RefBindings>(Sym, X); 3193 StmtNodeBuilder &Builder = C.getNodeBuilder(); 3194 3195 static SimpleProgramPointTag 3196 ReturnOwnLeakTag("RetainCountChecker : ReturnsOwnLeak"); 3197 ExplodedNode *N = Builder.generateNode(S, state, Pred, 3198 &ReturnOwnLeakTag); 3199 if (N) { 3200 const LangOptions &LOpts = C.getASTContext().getLangOptions(); 3201 bool GCEnabled = C.isObjCGCEnabled(); 3202 CFRefReport *report = 3203 new CFRefLeakReport(*getLeakAtReturnBug(LOpts, GCEnabled), 3204 LOpts, GCEnabled, SummaryLog, 3205 N, Sym, C.getEngine()); 3206 C.EmitReport(report); 3207 } 3208 } 3209 } 3210 } else if (X.isReturnedNotOwned()) { 3211 if (RE.isOwned()) { 3212 // Trying to return a not owned object to a caller expecting an 3213 // owned object. 3214 state = state->set<RefBindings>(Sym, X ^ RefVal::ErrorReturnedNotOwned); 3215 StmtNodeBuilder &Builder = C.getNodeBuilder(); 3216 3217 static SimpleProgramPointTag 3218 ReturnNotOwnedTag("RetainCountChecker : ReturnNotOwnedForOwned"); 3219 ExplodedNode *N = Builder.generateNode(S, state, Pred, 3220 &ReturnNotOwnedTag); 3221 if (N) { 3222 if (!returnNotOwnedForOwned) 3223 returnNotOwnedForOwned.reset(new ReturnedNotOwnedForOwned()); 3224 3225 CFRefReport *report = 3226 new CFRefReport(*returnNotOwnedForOwned, 3227 C.getASTContext().getLangOptions(), 3228 C.isObjCGCEnabled(), SummaryLog, N, Sym); 3229 C.EmitReport(report); 3230 } 3231 } 3232 } 3233} 3234 3235//===----------------------------------------------------------------------===// 3236// Check various ways a symbol can be invalidated. 3237//===----------------------------------------------------------------------===// 3238 3239void RetainCountChecker::checkBind(SVal loc, SVal val, 3240 CheckerContext &C) const { 3241 // Are we storing to something that causes the value to "escape"? 3242 bool escapes = true; 3243 3244 // A value escapes in three possible cases (this may change): 3245 // 3246 // (1) we are binding to something that is not a memory region. 3247 // (2) we are binding to a memregion that does not have stack storage 3248 // (3) we are binding to a memregion with stack storage that the store 3249 // does not understand. 3250 const ProgramState *state = C.getState(); 3251 3252 if (loc::MemRegionVal *regionLoc = dyn_cast<loc::MemRegionVal>(&loc)) { 3253 escapes = !regionLoc->getRegion()->hasStackStorage(); 3254 3255 if (!escapes) { 3256 // To test (3), generate a new state with the binding added. If it is 3257 // the same state, then it escapes (since the store cannot represent 3258 // the binding). 3259 escapes = (state == (state->bindLoc(*regionLoc, val))); 3260 } 3261 } 3262 3263 // If our store can represent the binding and we aren't storing to something 3264 // that doesn't have local storage then just return and have the simulation 3265 // state continue as is. 3266 if (!escapes) 3267 return; 3268 3269 // Otherwise, find all symbols referenced by 'val' that we are tracking 3270 // and stop tracking them. 3271 state = state->scanReachableSymbols<StopTrackingCallback>(val).getState(); 3272 C.addTransition(state); 3273} 3274 3275const ProgramState *RetainCountChecker::evalAssume(const ProgramState *state, 3276 SVal Cond, 3277 bool Assumption) const { 3278 3279 // FIXME: We may add to the interface of evalAssume the list of symbols 3280 // whose assumptions have changed. For now we just iterate through the 3281 // bindings and check if any of the tracked symbols are NULL. This isn't 3282 // too bad since the number of symbols we will track in practice are 3283 // probably small and evalAssume is only called at branches and a few 3284 // other places. 3285 RefBindings B = state->get<RefBindings>(); 3286 3287 if (B.isEmpty()) 3288 return state; 3289 3290 bool changed = false; 3291 RefBindings::Factory &RefBFactory = state->get_context<RefBindings>(); 3292 3293 for (RefBindings::iterator I = B.begin(), E = B.end(); I != E; ++I) { 3294 // Check if the symbol is null (or equal to any constant). 3295 // If this is the case, stop tracking the symbol. 3296 if (state->getSymVal(I.getKey())) { 3297 changed = true; 3298 B = RefBFactory.remove(B, I.getKey()); 3299 } 3300 } 3301 3302 if (changed) 3303 state = state->set<RefBindings>(B); 3304 3305 return state; 3306} 3307 3308const ProgramState * 3309RetainCountChecker::checkRegionChanges(const ProgramState *state, 3310 const StoreManager::InvalidatedSymbols *invalidated, 3311 ArrayRef<const MemRegion *> ExplicitRegions, 3312 ArrayRef<const MemRegion *> Regions) const { 3313 if (!invalidated) 3314 return state; 3315 3316 llvm::SmallPtrSet<SymbolRef, 8> WhitelistedSymbols; 3317 for (ArrayRef<const MemRegion *>::iterator I = ExplicitRegions.begin(), 3318 E = ExplicitRegions.end(); I != E; ++I) { 3319 if (const SymbolicRegion *SR = (*I)->StripCasts()->getAs<SymbolicRegion>()) 3320 WhitelistedSymbols.insert(SR->getSymbol()); 3321 } 3322 3323 for (StoreManager::InvalidatedSymbols::const_iterator I=invalidated->begin(), 3324 E = invalidated->end(); I!=E; ++I) { 3325 SymbolRef sym = *I; 3326 if (WhitelistedSymbols.count(sym)) 3327 continue; 3328 // Remove any existing reference-count binding. 3329 state = state->remove<RefBindings>(sym); 3330 } 3331 return state; 3332} 3333 3334//===----------------------------------------------------------------------===// 3335// Handle dead symbols and end-of-path. 3336//===----------------------------------------------------------------------===// 3337 3338std::pair<ExplodedNode *, const ProgramState *> 3339RetainCountChecker::handleAutoreleaseCounts(const ProgramState *state, 3340 GenericNodeBuilderRefCount Bd, 3341 ExplodedNode *Pred, ExprEngine &Eng, 3342 SymbolRef Sym, RefVal V) const { 3343 unsigned ACnt = V.getAutoreleaseCount(); 3344 3345 // No autorelease counts? Nothing to be done. 3346 if (!ACnt) 3347 return std::make_pair(Pred, state); 3348 3349 assert(!Eng.isObjCGCEnabled() && "Autorelease counts in GC mode?"); 3350 unsigned Cnt = V.getCount(); 3351 3352 // FIXME: Handle sending 'autorelease' to already released object. 3353 3354 if (V.getKind() == RefVal::ReturnedOwned) 3355 ++Cnt; 3356 3357 if (ACnt <= Cnt) { 3358 if (ACnt == Cnt) { 3359 V.clearCounts(); 3360 if (V.getKind() == RefVal::ReturnedOwned) 3361 V = V ^ RefVal::ReturnedNotOwned; 3362 else 3363 V = V ^ RefVal::NotOwned; 3364 } else { 3365 V.setCount(Cnt - ACnt); 3366 V.setAutoreleaseCount(0); 3367 } 3368 state = state->set<RefBindings>(Sym, V); 3369 ExplodedNode *N = Bd.MakeNode(state, Pred); 3370 if (N == 0) 3371 state = 0; 3372 return std::make_pair(N, state); 3373 } 3374 3375 // Woah! More autorelease counts then retain counts left. 3376 // Emit hard error. 3377 V = V ^ RefVal::ErrorOverAutorelease; 3378 state = state->set<RefBindings>(Sym, V); 3379 3380 if (ExplodedNode *N = Bd.MakeNode(state, Pred)) { 3381 N->markAsSink(); 3382 3383 llvm::SmallString<128> sbuf; 3384 llvm::raw_svector_ostream os(sbuf); 3385 os << "Object over-autoreleased: object was sent -autorelease "; 3386 if (V.getAutoreleaseCount() > 1) 3387 os << V.getAutoreleaseCount() << " times "; 3388 os << "but the object has a +" << V.getCount() << " retain count"; 3389 3390 if (!overAutorelease) 3391 overAutorelease.reset(new OverAutorelease()); 3392 3393 const LangOptions &LOpts = Eng.getContext().getLangOptions(); 3394 CFRefReport *report = 3395 new CFRefReport(*overAutorelease, LOpts, /* GCEnabled = */ false, 3396 SummaryLog, N, Sym, os.str()); 3397 Eng.getBugReporter().EmitReport(report); 3398 } 3399 3400 return std::make_pair((ExplodedNode *)0, (const ProgramState *)0); 3401} 3402 3403const ProgramState * 3404RetainCountChecker::handleSymbolDeath(const ProgramState *state, 3405 SymbolRef sid, RefVal V, 3406 SmallVectorImpl<SymbolRef> &Leaked) const { 3407 bool hasLeak = false; 3408 if (V.isOwned()) 3409 hasLeak = true; 3410 else if (V.isNotOwned() || V.isReturnedOwned()) 3411 hasLeak = (V.getCount() > 0); 3412 3413 if (!hasLeak) 3414 return state->remove<RefBindings>(sid); 3415 3416 Leaked.push_back(sid); 3417 return state->set<RefBindings>(sid, V ^ RefVal::ErrorLeak); 3418} 3419 3420ExplodedNode * 3421RetainCountChecker::processLeaks(const ProgramState *state, 3422 SmallVectorImpl<SymbolRef> &Leaked, 3423 GenericNodeBuilderRefCount &Builder, 3424 ExprEngine &Eng, ExplodedNode *Pred) const { 3425 if (Leaked.empty()) 3426 return Pred; 3427 3428 // Generate an intermediate node representing the leak point. 3429 ExplodedNode *N = Builder.MakeNode(state, Pred); 3430 3431 if (N) { 3432 for (SmallVectorImpl<SymbolRef>::iterator 3433 I = Leaked.begin(), E = Leaked.end(); I != E; ++I) { 3434 3435 const LangOptions &LOpts = Eng.getContext().getLangOptions(); 3436 bool GCEnabled = Eng.isObjCGCEnabled(); 3437 CFRefBug *BT = Pred ? getLeakWithinFunctionBug(LOpts, GCEnabled) 3438 : getLeakAtReturnBug(LOpts, GCEnabled); 3439 assert(BT && "BugType not initialized."); 3440 3441 CFRefLeakReport *report = new CFRefLeakReport(*BT, LOpts, GCEnabled, 3442 SummaryLog, N, *I, Eng); 3443 Eng.getBugReporter().EmitReport(report); 3444 } 3445 } 3446 3447 return N; 3448} 3449 3450void RetainCountChecker::checkEndPath(EndOfFunctionNodeBuilder &Builder, 3451 ExprEngine &Eng) const { 3452 const ProgramState *state = Builder.getState(); 3453 GenericNodeBuilderRefCount Bd(Builder); 3454 RefBindings B = state->get<RefBindings>(); 3455 ExplodedNode *Pred = 0; 3456 3457 for (RefBindings::iterator I = B.begin(), E = B.end(); I != E; ++I) { 3458 llvm::tie(Pred, state) = handleAutoreleaseCounts(state, Bd, Pred, Eng, 3459 I->first, I->second); 3460 if (!state) 3461 return; 3462 } 3463 3464 B = state->get<RefBindings>(); 3465 SmallVector<SymbolRef, 10> Leaked; 3466 3467 for (RefBindings::iterator I = B.begin(), E = B.end(); I != E; ++I) 3468 state = handleSymbolDeath(state, I->first, I->second, Leaked); 3469 3470 processLeaks(state, Leaked, Bd, Eng, Pred); 3471} 3472 3473const ProgramPointTag * 3474RetainCountChecker::getDeadSymbolTag(SymbolRef sym) const { 3475 const SimpleProgramPointTag *&tag = DeadSymbolTags[sym]; 3476 if (!tag) { 3477 llvm::SmallString<64> buf; 3478 llvm::raw_svector_ostream out(buf); 3479 out << "RetainCountChecker : Dead Symbol : " << sym->getSymbolID(); 3480 tag = new SimpleProgramPointTag(out.str()); 3481 } 3482 return tag; 3483} 3484 3485void RetainCountChecker::checkDeadSymbols(SymbolReaper &SymReaper, 3486 CheckerContext &C) const { 3487 StmtNodeBuilder &Builder = C.getNodeBuilder(); 3488 ExprEngine &Eng = C.getEngine(); 3489 const Stmt *S = C.getStmt(); 3490 ExplodedNode *Pred = C.getPredecessor(); 3491 3492 const ProgramState *state = C.getState(); 3493 RefBindings B = state->get<RefBindings>(); 3494 3495 // Update counts from autorelease pools 3496 for (SymbolReaper::dead_iterator I = SymReaper.dead_begin(), 3497 E = SymReaper.dead_end(); I != E; ++I) { 3498 SymbolRef Sym = *I; 3499 if (const RefVal *T = B.lookup(Sym)){ 3500 // Use the symbol as the tag. 3501 // FIXME: This might not be as unique as we would like. 3502 GenericNodeBuilderRefCount Bd(Builder, S, getDeadSymbolTag(Sym)); 3503 llvm::tie(Pred, state) = handleAutoreleaseCounts(state, Bd, Pred, Eng, 3504 Sym, *T); 3505 if (!state) 3506 return; 3507 } 3508 } 3509 3510 B = state->get<RefBindings>(); 3511 SmallVector<SymbolRef, 10> Leaked; 3512 3513 for (SymbolReaper::dead_iterator I = SymReaper.dead_begin(), 3514 E = SymReaper.dead_end(); I != E; ++I) { 3515 if (const RefVal *T = B.lookup(*I)) 3516 state = handleSymbolDeath(state, *I, *T, Leaked); 3517 } 3518 3519 { 3520 GenericNodeBuilderRefCount Bd(Builder, S, this); 3521 Pred = processLeaks(state, Leaked, Bd, Eng, Pred); 3522 } 3523 3524 // Did we cache out? 3525 if (!Pred) 3526 return; 3527 3528 // Now generate a new node that nukes the old bindings. 3529 RefBindings::Factory &F = state->get_context<RefBindings>(); 3530 3531 for (SymbolReaper::dead_iterator I = SymReaper.dead_begin(), 3532 E = SymReaper.dead_end(); I != E; ++I) 3533 B = F.remove(B, *I); 3534 3535 state = state->set<RefBindings>(B); 3536 C.generateNode(state, Pred); 3537} 3538 3539//===----------------------------------------------------------------------===// 3540// Debug printing of refcount bindings and autorelease pools. 3541//===----------------------------------------------------------------------===// 3542 3543static void PrintPool(raw_ostream &Out, SymbolRef Sym, 3544 const ProgramState *State) { 3545 Out << ' '; 3546 if (Sym) 3547 Out << Sym->getSymbolID(); 3548 else 3549 Out << "<pool>"; 3550 Out << ":{"; 3551 3552 // Get the contents of the pool. 3553 if (const ARCounts *Cnts = State->get<AutoreleasePoolContents>(Sym)) 3554 for (ARCounts::iterator I = Cnts->begin(), E = Cnts->end(); I != E; ++I) 3555 Out << '(' << I.getKey() << ',' << I.getData() << ')'; 3556 3557 Out << '}'; 3558} 3559 3560bool UsesAutorelease(const ProgramState *state) { 3561 // A state uses autorelease if it allocated an autorelease pool or if it has 3562 // objects in the caller's autorelease pool. 3563 return !state->get<AutoreleaseStack>().isEmpty() || 3564 state->get<AutoreleasePoolContents>(SymbolRef()); 3565} 3566 3567void RetainCountChecker::printState(raw_ostream &Out, const ProgramState *State, 3568 const char *NL, const char *Sep) const { 3569 3570 RefBindings B = State->get<RefBindings>(); 3571 3572 if (!B.isEmpty()) 3573 Out << Sep << NL; 3574 3575 for (RefBindings::iterator I = B.begin(), E = B.end(); I != E; ++I) { 3576 Out << I->first << " : "; 3577 I->second.print(Out); 3578 Out << NL; 3579 } 3580 3581 // Print the autorelease stack. 3582 if (UsesAutorelease(State)) { 3583 Out << Sep << NL << "AR pool stack:"; 3584 ARStack Stack = State->get<AutoreleaseStack>(); 3585 3586 PrintPool(Out, SymbolRef(), State); // Print the caller's pool. 3587 for (ARStack::iterator I = Stack.begin(), E = Stack.end(); I != E; ++I) 3588 PrintPool(Out, *I, State); 3589 3590 Out << NL; 3591 } 3592} 3593 3594//===----------------------------------------------------------------------===// 3595// Checker registration. 3596//===----------------------------------------------------------------------===// 3597 3598void ento::registerRetainCountChecker(CheckerManager &Mgr) { 3599 Mgr.registerChecker<RetainCountChecker>(); 3600} 3601 3602