RetainCountChecker.cpp revision 220ac8c175cb1bf9b18d82eefe036995d7a2164d
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.getGC()) { 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 N->getLocationContext()); 1880 return new PathDiagnosticEventPiece(Pos, os.str()); 1881 } 1882 1883 // Gather up the effects that were performed on the object at this 1884 // program point 1885 SmallVector<ArgEffect, 2> AEffects; 1886 1887 const ExplodedNode *OrigNode = BRC.getNodeResolver().getOriginalNode(N); 1888 if (const RetainSummary *Summ = SummaryLog.lookup(OrigNode)) { 1889 // We only have summaries attached to nodes after evaluating CallExpr and 1890 // ObjCMessageExprs. 1891 const Stmt *S = cast<StmtPoint>(N->getLocation()).getStmt(); 1892 1893 if (const CallExpr *CE = dyn_cast<CallExpr>(S)) { 1894 // Iterate through the parameter expressions and see if the symbol 1895 // was ever passed as an argument. 1896 unsigned i = 0; 1897 1898 for (CallExpr::const_arg_iterator AI=CE->arg_begin(), AE=CE->arg_end(); 1899 AI!=AE; ++AI, ++i) { 1900 1901 // Retrieve the value of the argument. Is it the symbol 1902 // we are interested in? 1903 if (CurrSt->getSValAsScalarOrLoc(*AI).getAsLocSymbol() != Sym) 1904 continue; 1905 1906 // We have an argument. Get the effect! 1907 AEffects.push_back(Summ->getArg(i)); 1908 } 1909 } 1910 else if (const ObjCMessageExpr *ME = dyn_cast<ObjCMessageExpr>(S)) { 1911 if (const Expr *receiver = ME->getInstanceReceiver()) 1912 if (CurrSt->getSValAsScalarOrLoc(receiver).getAsLocSymbol() == Sym) { 1913 // The symbol we are tracking is the receiver. 1914 AEffects.push_back(Summ->getReceiverEffect()); 1915 } 1916 } 1917 } 1918 1919 do { 1920 // Get the previous type state. 1921 RefVal PrevV = *PrevT; 1922 1923 // Specially handle -dealloc. 1924 if (!GCEnabled && contains(AEffects, Dealloc)) { 1925 // Determine if the object's reference count was pushed to zero. 1926 assert(!(PrevV == CurrV) && "The typestate *must* have changed."); 1927 // We may not have transitioned to 'release' if we hit an error. 1928 // This case is handled elsewhere. 1929 if (CurrV.getKind() == RefVal::Released) { 1930 assert(CurrV.getCombinedCounts() == 0); 1931 os << "Object released by directly sending the '-dealloc' message"; 1932 break; 1933 } 1934 } 1935 1936 // Specially handle CFMakeCollectable and friends. 1937 if (contains(AEffects, MakeCollectable)) { 1938 // Get the name of the function. 1939 const Stmt *S = cast<StmtPoint>(N->getLocation()).getStmt(); 1940 SVal X = CurrSt->getSValAsScalarOrLoc(cast<CallExpr>(S)->getCallee()); 1941 const FunctionDecl *FD = X.getAsFunctionDecl(); 1942 1943 if (GCEnabled) { 1944 // Determine if the object's reference count was pushed to zero. 1945 assert(!(PrevV == CurrV) && "The typestate *must* have changed."); 1946 1947 os << "In GC mode a call to '" << FD 1948 << "' decrements an object's retain count and registers the " 1949 "object with the garbage collector. "; 1950 1951 if (CurrV.getKind() == RefVal::Released) { 1952 assert(CurrV.getCount() == 0); 1953 os << "Since it now has a 0 retain count the object can be " 1954 "automatically collected by the garbage collector."; 1955 } 1956 else 1957 os << "An object must have a 0 retain count to be garbage collected. " 1958 "After this call its retain count is +" << CurrV.getCount() 1959 << '.'; 1960 } 1961 else 1962 os << "When GC is not enabled a call to '" << FD 1963 << "' has no effect on its argument."; 1964 1965 // Nothing more to say. 1966 break; 1967 } 1968 1969 // Determine if the typestate has changed. 1970 if (!(PrevV == CurrV)) 1971 switch (CurrV.getKind()) { 1972 case RefVal::Owned: 1973 case RefVal::NotOwned: 1974 1975 if (PrevV.getCount() == CurrV.getCount()) { 1976 // Did an autorelease message get sent? 1977 if (PrevV.getAutoreleaseCount() == CurrV.getAutoreleaseCount()) 1978 return 0; 1979 1980 assert(PrevV.getAutoreleaseCount() < CurrV.getAutoreleaseCount()); 1981 os << "Object sent -autorelease message"; 1982 break; 1983 } 1984 1985 if (PrevV.getCount() > CurrV.getCount()) 1986 os << "Reference count decremented."; 1987 else 1988 os << "Reference count incremented."; 1989 1990 if (unsigned Count = CurrV.getCount()) 1991 os << " The object now has a +" << Count << " retain count."; 1992 1993 if (PrevV.getKind() == RefVal::Released) { 1994 assert(GCEnabled && CurrV.getCount() > 0); 1995 os << " The object is not eligible for garbage collection until the " 1996 "retain count reaches 0 again."; 1997 } 1998 1999 break; 2000 2001 case RefVal::Released: 2002 os << "Object released."; 2003 break; 2004 2005 case RefVal::ReturnedOwned: 2006 os << "Object returned to caller as an owning reference (single retain " 2007 "count transferred to caller)"; 2008 break; 2009 2010 case RefVal::ReturnedNotOwned: 2011 os << "Object returned to caller with a +0 retain count"; 2012 break; 2013 2014 default: 2015 return NULL; 2016 } 2017 2018 // Emit any remaining diagnostics for the argument effects (if any). 2019 for (SmallVectorImpl<ArgEffect>::iterator I=AEffects.begin(), 2020 E=AEffects.end(); I != E; ++I) { 2021 2022 // A bunch of things have alternate behavior under GC. 2023 if (GCEnabled) 2024 switch (*I) { 2025 default: break; 2026 case Autorelease: 2027 os << "In GC mode an 'autorelease' has no effect."; 2028 continue; 2029 case IncRefMsg: 2030 os << "In GC mode the 'retain' message has no effect."; 2031 continue; 2032 case DecRefMsg: 2033 os << "In GC mode the 'release' message has no effect."; 2034 continue; 2035 } 2036 } 2037 } while (0); 2038 2039 if (os.str().empty()) 2040 return 0; // We have nothing to say! 2041 2042 const Stmt *S = cast<StmtPoint>(N->getLocation()).getStmt(); 2043 PathDiagnosticLocation Pos(S, BRC.getSourceManager(), 2044 N->getLocationContext()); 2045 PathDiagnosticPiece *P = new PathDiagnosticEventPiece(Pos, os.str()); 2046 2047 // Add the range by scanning the children of the statement for any bindings 2048 // to Sym. 2049 for (Stmt::const_child_iterator I = S->child_begin(), E = S->child_end(); 2050 I!=E; ++I) 2051 if (const Expr *Exp = dyn_cast_or_null<Expr>(*I)) 2052 if (CurrSt->getSValAsScalarOrLoc(Exp).getAsLocSymbol() == Sym) { 2053 P->addRange(Exp->getSourceRange()); 2054 break; 2055 } 2056 2057 return P; 2058} 2059 2060namespace { 2061 class FindUniqueBinding : 2062 public StoreManager::BindingsHandler { 2063 SymbolRef Sym; 2064 const MemRegion* Binding; 2065 bool First; 2066 2067 public: 2068 FindUniqueBinding(SymbolRef sym) : Sym(sym), Binding(0), First(true) {} 2069 2070 bool HandleBinding(StoreManager& SMgr, Store store, const MemRegion* R, 2071 SVal val) { 2072 2073 SymbolRef SymV = val.getAsSymbol(); 2074 if (!SymV || SymV != Sym) 2075 return true; 2076 2077 if (Binding) { 2078 First = false; 2079 return false; 2080 } 2081 else 2082 Binding = R; 2083 2084 return true; 2085 } 2086 2087 operator bool() { return First && Binding; } 2088 const MemRegion* getRegion() { return Binding; } 2089 }; 2090} 2091 2092static std::pair<const ExplodedNode*,const MemRegion*> 2093GetAllocationSite(ProgramStateManager& StateMgr, const ExplodedNode *N, 2094 SymbolRef Sym) { 2095 2096 // Find both first node that referred to the tracked symbol and the 2097 // memory location that value was store to. 2098 const ExplodedNode *Last = N; 2099 const MemRegion* FirstBinding = 0; 2100 2101 while (N) { 2102 const ProgramState *St = N->getState(); 2103 RefBindings B = St->get<RefBindings>(); 2104 2105 if (!B.lookup(Sym)) 2106 break; 2107 2108 FindUniqueBinding FB(Sym); 2109 StateMgr.iterBindings(St, FB); 2110 if (FB) FirstBinding = FB.getRegion(); 2111 2112 Last = N; 2113 N = N->pred_empty() ? NULL : *(N->pred_begin()); 2114 } 2115 2116 return std::make_pair(Last, FirstBinding); 2117} 2118 2119PathDiagnosticPiece* 2120CFRefReportVisitor::getEndPath(BugReporterContext &BRC, 2121 const ExplodedNode *EndN, 2122 BugReport &BR) { 2123 // Tell the BugReporterContext to report cases when the tracked symbol is 2124 // assigned to different variables, etc. 2125 BRC.addNotableSymbol(Sym); 2126 return BugReporterVisitor::getDefaultEndPath(BRC, EndN, BR); 2127} 2128 2129PathDiagnosticPiece* 2130CFRefLeakReportVisitor::getEndPath(BugReporterContext &BRC, 2131 const ExplodedNode *EndN, 2132 BugReport &BR) { 2133 2134 // Tell the BugReporterContext to report cases when the tracked symbol is 2135 // assigned to different variables, etc. 2136 BRC.addNotableSymbol(Sym); 2137 2138 // We are reporting a leak. Walk up the graph to get to the first node where 2139 // the symbol appeared, and also get the first VarDecl that tracked object 2140 // is stored to. 2141 const ExplodedNode *AllocNode = 0; 2142 const MemRegion* FirstBinding = 0; 2143 2144 llvm::tie(AllocNode, FirstBinding) = 2145 GetAllocationSite(BRC.getStateManager(), EndN, Sym); 2146 2147 SourceManager& SMgr = BRC.getSourceManager(); 2148 2149 // Compute an actual location for the leak. Sometimes a leak doesn't 2150 // occur at an actual statement (e.g., transition between blocks; end 2151 // of function) so we need to walk the graph and compute a real location. 2152 const ExplodedNode *LeakN = EndN; 2153 PathDiagnosticLocation L = PathDiagnosticLocation::create(LeakN, SMgr); 2154 2155 std::string sbuf; 2156 llvm::raw_string_ostream os(sbuf); 2157 2158 os << "Object leaked: "; 2159 2160 if (FirstBinding) { 2161 os << "object allocated and stored into '" 2162 << FirstBinding->getString() << '\''; 2163 } 2164 else 2165 os << "allocated object"; 2166 2167 // Get the retain count. 2168 const RefVal* RV = EndN->getState()->get<RefBindings>(Sym); 2169 2170 if (RV->getKind() == RefVal::ErrorLeakReturned) { 2171 // FIXME: Per comments in rdar://6320065, "create" only applies to CF 2172 // objects. Only "copy", "alloc", "retain" and "new" transfer ownership 2173 // to the caller for NS objects. 2174 const Decl *D = &EndN->getCodeDecl(); 2175 if (const ObjCMethodDecl *MD = dyn_cast<ObjCMethodDecl>(D)) { 2176 os << " is returned from a method whose name ('" 2177 << MD->getSelector().getAsString() 2178 << "') does not start with 'copy', 'mutableCopy', 'alloc' or 'new'." 2179 " This violates the naming convention rules" 2180 " given in the Memory Management Guide for Cocoa"; 2181 } 2182 else { 2183 const FunctionDecl *FD = cast<FunctionDecl>(D); 2184 os << " is return from a function whose name ('" 2185 << FD->getNameAsString() 2186 << "') does not contain 'Copy' or 'Create'. This violates the naming" 2187 " convention rules given the Memory Management Guide for Core" 2188 " Foundation"; 2189 } 2190 } 2191 else if (RV->getKind() == RefVal::ErrorGCLeakReturned) { 2192 ObjCMethodDecl &MD = cast<ObjCMethodDecl>(EndN->getCodeDecl()); 2193 os << " and returned from method '" << MD.getSelector().getAsString() 2194 << "' is potentially leaked when using garbage collection. Callers " 2195 "of this method do not expect a returned object with a +1 retain " 2196 "count since they expect the object to be managed by the garbage " 2197 "collector"; 2198 } 2199 else 2200 os << " is not referenced later in this execution path and has a retain " 2201 "count of +" << RV->getCount(); 2202 2203 return new PathDiagnosticEventPiece(L, os.str()); 2204} 2205 2206CFRefLeakReport::CFRefLeakReport(CFRefBug &D, const LangOptions &LOpts, 2207 bool GCEnabled, const SummaryLogTy &Log, 2208 ExplodedNode *n, SymbolRef sym, 2209 ExprEngine &Eng) 2210: CFRefReport(D, LOpts, GCEnabled, Log, n, sym, false) { 2211 2212 // Most bug reports are cached at the location where they occurred. 2213 // With leaks, we want to unique them by the location where they were 2214 // allocated, and only report a single path. To do this, we need to find 2215 // the allocation site of a piece of tracked memory, which we do via a 2216 // call to GetAllocationSite. This will walk the ExplodedGraph backwards. 2217 // Note that this is *not* the trimmed graph; we are guaranteed, however, 2218 // that all ancestor nodes that represent the allocation site have the 2219 // same SourceLocation. 2220 const ExplodedNode *AllocNode = 0; 2221 2222 llvm::tie(AllocNode, AllocBinding) = // Set AllocBinding. 2223 GetAllocationSite(Eng.getStateManager(), getErrorNode(), sym); 2224 2225 // Get the SourceLocation for the allocation site. 2226 ProgramPoint P = AllocNode->getLocation(); 2227 AllocSite = cast<PostStmt>(P).getStmt()->getLocStart(); 2228 2229 // Fill in the description of the bug. 2230 Description.clear(); 2231 llvm::raw_string_ostream os(Description); 2232 SourceManager& SMgr = Eng.getContext().getSourceManager(); 2233 unsigned AllocLine = SMgr.getExpansionLineNumber(AllocSite); 2234 os << "Potential leak "; 2235 if (GCEnabled) 2236 os << "(when using garbage collection) "; 2237 os << "of an object allocated on line " << AllocLine; 2238 2239 // FIXME: AllocBinding doesn't get populated for RegionStore yet. 2240 if (AllocBinding) 2241 os << " and stored into '" << AllocBinding->getString() << '\''; 2242 2243 addVisitor(new CFRefLeakReportVisitor(sym, GCEnabled, Log)); 2244} 2245 2246//===----------------------------------------------------------------------===// 2247// Main checker logic. 2248//===----------------------------------------------------------------------===// 2249 2250namespace { 2251class RetainCountChecker 2252 : public Checker< check::Bind, 2253 check::DeadSymbols, 2254 check::EndAnalysis, 2255 check::EndPath, 2256 check::PostStmt<BlockExpr>, 2257 check::PostStmt<CastExpr>, 2258 check::PostStmt<CallExpr>, 2259 check::PostStmt<CXXConstructExpr>, 2260 check::PostObjCMessage, 2261 check::PreStmt<ReturnStmt>, 2262 check::RegionChanges, 2263 eval::Assume, 2264 eval::Call > { 2265 mutable llvm::OwningPtr<CFRefBug> useAfterRelease, releaseNotOwned; 2266 mutable llvm::OwningPtr<CFRefBug> deallocGC, deallocNotOwned; 2267 mutable llvm::OwningPtr<CFRefBug> overAutorelease, returnNotOwnedForOwned; 2268 mutable llvm::OwningPtr<CFRefBug> leakWithinFunction, leakAtReturn; 2269 mutable llvm::OwningPtr<CFRefBug> leakWithinFunctionGC, leakAtReturnGC; 2270 2271 typedef llvm::DenseMap<SymbolRef, const SimpleProgramPointTag *> SymbolTagMap; 2272 2273 // This map is only used to ensure proper deletion of any allocated tags. 2274 mutable SymbolTagMap DeadSymbolTags; 2275 2276 mutable llvm::OwningPtr<RetainSummaryManager> Summaries; 2277 mutable llvm::OwningPtr<RetainSummaryManager> SummariesGC; 2278 2279 mutable ARCounts::Factory ARCountFactory; 2280 2281 mutable SummaryLogTy SummaryLog; 2282 mutable bool ShouldResetSummaryLog; 2283 2284public: 2285 RetainCountChecker() : ShouldResetSummaryLog(false) {} 2286 2287 virtual ~RetainCountChecker() { 2288 DeleteContainerSeconds(DeadSymbolTags); 2289 } 2290 2291 void checkEndAnalysis(ExplodedGraph &G, BugReporter &BR, 2292 ExprEngine &Eng) const { 2293 // FIXME: This is a hack to make sure the summary log gets cleared between 2294 // analyses of different code bodies. 2295 // 2296 // Why is this necessary? Because a checker's lifetime is tied to a 2297 // translation unit, but an ExplodedGraph's lifetime is just a code body. 2298 // Once in a blue moon, a new ExplodedNode will have the same address as an 2299 // old one with an associated summary, and the bug report visitor gets very 2300 // confused. (To make things worse, the summary lifetime is currently also 2301 // tied to a code body, so we get a crash instead of incorrect results.) 2302 // 2303 // Why is this a bad solution? Because if the lifetime of the ExplodedGraph 2304 // changes, things will start going wrong again. Really the lifetime of this 2305 // log needs to be tied to either the specific nodes in it or the entire 2306 // ExplodedGraph, not to a specific part of the code being analyzed. 2307 // 2308 // (Also, having stateful local data means that the same checker can't be 2309 // used from multiple threads, but a lot of checkers have incorrect 2310 // assumptions about that anyway. So that wasn't a priority at the time of 2311 // this fix.) 2312 // 2313 // This happens at the end of analysis, but bug reports are emitted /after/ 2314 // this point. So we can't just clear the summary log now. Instead, we mark 2315 // that the next time we access the summary log, it should be cleared. 2316 2317 // If we never reset the summary log during /this/ code body analysis, 2318 // there were no new summaries. There might still have been summaries from 2319 // the /last/ analysis, so clear them out to make sure the bug report 2320 // visitors don't get confused. 2321 if (ShouldResetSummaryLog) 2322 SummaryLog.clear(); 2323 2324 ShouldResetSummaryLog = !SummaryLog.empty(); 2325 } 2326 2327 CFRefBug *getLeakWithinFunctionBug(const LangOptions &LOpts, 2328 bool GCEnabled) const { 2329 if (GCEnabled) { 2330 if (!leakWithinFunctionGC) 2331 leakWithinFunctionGC.reset(new LeakWithinFunction("Leak of object when " 2332 "using garbage " 2333 "collection")); 2334 return leakWithinFunctionGC.get(); 2335 } else { 2336 if (!leakWithinFunction) { 2337 if (LOpts.getGC() == LangOptions::HybridGC) { 2338 leakWithinFunction.reset(new LeakWithinFunction("Leak of object when " 2339 "not using garbage " 2340 "collection (GC) in " 2341 "dual GC/non-GC " 2342 "code")); 2343 } else { 2344 leakWithinFunction.reset(new LeakWithinFunction("Leak")); 2345 } 2346 } 2347 return leakWithinFunction.get(); 2348 } 2349 } 2350 2351 CFRefBug *getLeakAtReturnBug(const LangOptions &LOpts, bool GCEnabled) const { 2352 if (GCEnabled) { 2353 if (!leakAtReturnGC) 2354 leakAtReturnGC.reset(new LeakAtReturn("Leak of returned object when " 2355 "using garbage collection")); 2356 return leakAtReturnGC.get(); 2357 } else { 2358 if (!leakAtReturn) { 2359 if (LOpts.getGC() == LangOptions::HybridGC) { 2360 leakAtReturn.reset(new LeakAtReturn("Leak of returned object when " 2361 "not using garbage collection " 2362 "(GC) in dual GC/non-GC code")); 2363 } else { 2364 leakAtReturn.reset(new LeakAtReturn("Leak of returned object")); 2365 } 2366 } 2367 return leakAtReturn.get(); 2368 } 2369 } 2370 2371 RetainSummaryManager &getSummaryManager(ASTContext &Ctx, 2372 bool GCEnabled) const { 2373 // FIXME: We don't support ARC being turned on and off during one analysis. 2374 // (nor, for that matter, do we support changing ASTContexts) 2375 bool ARCEnabled = (bool)Ctx.getLangOptions().ObjCAutoRefCount; 2376 if (GCEnabled) { 2377 if (!SummariesGC) 2378 SummariesGC.reset(new RetainSummaryManager(Ctx, true, ARCEnabled)); 2379 else 2380 assert(SummariesGC->isARCEnabled() == ARCEnabled); 2381 return *SummariesGC; 2382 } else { 2383 if (!Summaries) 2384 Summaries.reset(new RetainSummaryManager(Ctx, false, ARCEnabled)); 2385 else 2386 assert(Summaries->isARCEnabled() == ARCEnabled); 2387 return *Summaries; 2388 } 2389 } 2390 2391 RetainSummaryManager &getSummaryManager(CheckerContext &C) const { 2392 return getSummaryManager(C.getASTContext(), C.isObjCGCEnabled()); 2393 } 2394 2395 void printState(raw_ostream &Out, const ProgramState *State, 2396 const char *NL, const char *Sep) const; 2397 2398 void checkBind(SVal loc, SVal val, CheckerContext &C) const; 2399 void checkPostStmt(const BlockExpr *BE, CheckerContext &C) const; 2400 void checkPostStmt(const CastExpr *CE, CheckerContext &C) const; 2401 2402 void checkPostStmt(const CallExpr *CE, CheckerContext &C) const; 2403 void checkPostStmt(const CXXConstructExpr *CE, CheckerContext &C) const; 2404 void checkPostObjCMessage(const ObjCMessage &Msg, CheckerContext &C) const; 2405 void checkSummary(const RetainSummary &Summ, const CallOrObjCMessage &Call, 2406 CheckerContext &C) const; 2407 2408 bool evalCall(const CallExpr *CE, CheckerContext &C) const; 2409 2410 const ProgramState *evalAssume(const ProgramState *state, SVal Cond, 2411 bool Assumption) const; 2412 2413 const ProgramState * 2414 checkRegionChanges(const ProgramState *state, 2415 const StoreManager::InvalidatedSymbols *invalidated, 2416 ArrayRef<const MemRegion *> ExplicitRegions, 2417 ArrayRef<const MemRegion *> Regions) const; 2418 2419 bool wantsRegionChangeUpdate(const ProgramState *state) const { 2420 return true; 2421 } 2422 2423 void checkPreStmt(const ReturnStmt *S, CheckerContext &C) const; 2424 void checkReturnWithRetEffect(const ReturnStmt *S, CheckerContext &C, 2425 ExplodedNode *Pred, RetEffect RE, RefVal X, 2426 SymbolRef Sym, const ProgramState *state) const; 2427 2428 void checkDeadSymbols(SymbolReaper &SymReaper, CheckerContext &C) const; 2429 void checkEndPath(EndOfFunctionNodeBuilder &Builder, ExprEngine &Eng) const; 2430 2431 const ProgramState *updateSymbol(const ProgramState *state, SymbolRef sym, 2432 RefVal V, ArgEffect E, RefVal::Kind &hasErr, 2433 CheckerContext &C) const; 2434 2435 void processNonLeakError(const ProgramState *St, SourceRange ErrorRange, 2436 RefVal::Kind ErrorKind, SymbolRef Sym, 2437 CheckerContext &C) const; 2438 2439 const ProgramPointTag *getDeadSymbolTag(SymbolRef sym) const; 2440 2441 const ProgramState *handleSymbolDeath(const ProgramState *state, 2442 SymbolRef sid, RefVal V, 2443 SmallVectorImpl<SymbolRef> &Leaked) const; 2444 2445 std::pair<ExplodedNode *, const ProgramState *> 2446 handleAutoreleaseCounts(const ProgramState *state, 2447 GenericNodeBuilderRefCount Bd, ExplodedNode *Pred, 2448 ExprEngine &Eng, SymbolRef Sym, RefVal V) const; 2449 2450 ExplodedNode *processLeaks(const ProgramState *state, 2451 SmallVectorImpl<SymbolRef> &Leaked, 2452 GenericNodeBuilderRefCount &Builder, 2453 ExprEngine &Eng, 2454 ExplodedNode *Pred = 0) const; 2455}; 2456} // end anonymous namespace 2457 2458namespace { 2459class StopTrackingCallback : public SymbolVisitor { 2460 const ProgramState *state; 2461public: 2462 StopTrackingCallback(const ProgramState *st) : state(st) {} 2463 const ProgramState *getState() const { return state; } 2464 2465 bool VisitSymbol(SymbolRef sym) { 2466 state = state->remove<RefBindings>(sym); 2467 return true; 2468 } 2469}; 2470} // end anonymous namespace 2471 2472//===----------------------------------------------------------------------===// 2473// Handle statements that may have an effect on refcounts. 2474//===----------------------------------------------------------------------===// 2475 2476void RetainCountChecker::checkPostStmt(const BlockExpr *BE, 2477 CheckerContext &C) const { 2478 2479 // Scan the BlockDecRefExprs for any object the retain count checker 2480 // may be tracking. 2481 if (!BE->getBlockDecl()->hasCaptures()) 2482 return; 2483 2484 const ProgramState *state = C.getState(); 2485 const BlockDataRegion *R = 2486 cast<BlockDataRegion>(state->getSVal(BE).getAsRegion()); 2487 2488 BlockDataRegion::referenced_vars_iterator I = R->referenced_vars_begin(), 2489 E = R->referenced_vars_end(); 2490 2491 if (I == E) 2492 return; 2493 2494 // FIXME: For now we invalidate the tracking of all symbols passed to blocks 2495 // via captured variables, even though captured variables result in a copy 2496 // and in implicit increment/decrement of a retain count. 2497 SmallVector<const MemRegion*, 10> Regions; 2498 const LocationContext *LC = C.getPredecessor()->getLocationContext(); 2499 MemRegionManager &MemMgr = C.getSValBuilder().getRegionManager(); 2500 2501 for ( ; I != E; ++I) { 2502 const VarRegion *VR = *I; 2503 if (VR->getSuperRegion() == R) { 2504 VR = MemMgr.getVarRegion(VR->getDecl(), LC); 2505 } 2506 Regions.push_back(VR); 2507 } 2508 2509 state = 2510 state->scanReachableSymbols<StopTrackingCallback>(Regions.data(), 2511 Regions.data() + Regions.size()).getState(); 2512 C.addTransition(state); 2513} 2514 2515void RetainCountChecker::checkPostStmt(const CastExpr *CE, 2516 CheckerContext &C) const { 2517 const ObjCBridgedCastExpr *BE = dyn_cast<ObjCBridgedCastExpr>(CE); 2518 if (!BE) 2519 return; 2520 2521 ArgEffect AE = IncRef; 2522 2523 switch (BE->getBridgeKind()) { 2524 case clang::OBC_Bridge: 2525 // Do nothing. 2526 return; 2527 case clang::OBC_BridgeRetained: 2528 AE = IncRef; 2529 break; 2530 case clang::OBC_BridgeTransfer: 2531 AE = DecRefBridgedTransfered; 2532 break; 2533 } 2534 2535 const ProgramState *state = C.getState(); 2536 SymbolRef Sym = state->getSVal(CE).getAsLocSymbol(); 2537 if (!Sym) 2538 return; 2539 const RefVal* T = state->get<RefBindings>(Sym); 2540 if (!T) 2541 return; 2542 2543 RefVal::Kind hasErr = (RefVal::Kind) 0; 2544 state = updateSymbol(state, Sym, *T, AE, hasErr, C); 2545 2546 if (hasErr) { 2547 // FIXME: If we get an error during a bridge cast, should we report it? 2548 // Should we assert that there is no error? 2549 return; 2550 } 2551 2552 C.generateNode(state); 2553} 2554 2555void RetainCountChecker::checkPostStmt(const CallExpr *CE, 2556 CheckerContext &C) const { 2557 // Get the callee. 2558 const ProgramState *state = C.getState(); 2559 const Expr *Callee = CE->getCallee(); 2560 SVal L = state->getSVal(Callee); 2561 2562 RetainSummaryManager &Summaries = getSummaryManager(C); 2563 RetainSummary *Summ = 0; 2564 2565 // FIXME: Better support for blocks. For now we stop tracking anything 2566 // that is passed to blocks. 2567 // FIXME: Need to handle variables that are "captured" by the block. 2568 if (dyn_cast_or_null<BlockDataRegion>(L.getAsRegion())) { 2569 Summ = Summaries.getPersistentStopSummary(); 2570 } else if (const FunctionDecl *FD = L.getAsFunctionDecl()) { 2571 Summ = Summaries.getSummary(FD); 2572 } else if (const CXXMemberCallExpr *me = dyn_cast<CXXMemberCallExpr>(CE)) { 2573 if (const CXXMethodDecl *MD = me->getMethodDecl()) 2574 Summ = Summaries.getSummary(MD); 2575 } 2576 2577 // If we didn't get a summary, this function doesn't affect retain counts. 2578 if (!Summ) 2579 return; 2580 2581 checkSummary(*Summ, CallOrObjCMessage(CE, state), C); 2582} 2583 2584void RetainCountChecker::checkPostStmt(const CXXConstructExpr *CE, 2585 CheckerContext &C) const { 2586 const CXXConstructorDecl *Ctor = CE->getConstructor(); 2587 if (!Ctor) 2588 return; 2589 2590 RetainSummaryManager &Summaries = getSummaryManager(C); 2591 RetainSummary *Summ = Summaries.getSummary(Ctor); 2592 2593 // If we didn't get a summary, this constructor doesn't affect retain counts. 2594 if (!Summ) 2595 return; 2596 2597 const ProgramState *state = C.getState(); 2598 checkSummary(*Summ, CallOrObjCMessage(CE, state), C); 2599} 2600 2601void RetainCountChecker::checkPostObjCMessage(const ObjCMessage &Msg, 2602 CheckerContext &C) const { 2603 const ProgramState *state = C.getState(); 2604 ExplodedNode *Pred = C.getPredecessor(); 2605 2606 RetainSummaryManager &Summaries = getSummaryManager(C); 2607 2608 RetainSummary *Summ; 2609 if (Msg.isInstanceMessage()) { 2610 const LocationContext *LC = Pred->getLocationContext(); 2611 Summ = Summaries.getInstanceMethodSummary(Msg, state, LC); 2612 } else { 2613 Summ = Summaries.getClassMethodSummary(Msg); 2614 } 2615 2616 // If we didn't get a summary, this message doesn't affect retain counts. 2617 if (!Summ) 2618 return; 2619 2620 checkSummary(*Summ, CallOrObjCMessage(Msg, state), C); 2621} 2622 2623/// GetReturnType - Used to get the return type of a message expression or 2624/// function call with the intention of affixing that type to a tracked symbol. 2625/// While the the return type can be queried directly from RetEx, when 2626/// invoking class methods we augment to the return type to be that of 2627/// a pointer to the class (as opposed it just being id). 2628// FIXME: We may be able to do this with related result types instead. 2629// This function is probably overestimating. 2630static QualType GetReturnType(const Expr *RetE, ASTContext &Ctx) { 2631 QualType RetTy = RetE->getType(); 2632 // If RetE is not a message expression just return its type. 2633 // If RetE is a message expression, return its types if it is something 2634 /// more specific than id. 2635 if (const ObjCMessageExpr *ME = dyn_cast<ObjCMessageExpr>(RetE)) 2636 if (const ObjCObjectPointerType *PT = RetTy->getAs<ObjCObjectPointerType>()) 2637 if (PT->isObjCQualifiedIdType() || PT->isObjCIdType() || 2638 PT->isObjCClassType()) { 2639 // At this point we know the return type of the message expression is 2640 // id, id<...>, or Class. If we have an ObjCInterfaceDecl, we know this 2641 // is a call to a class method whose type we can resolve. In such 2642 // cases, promote the return type to XXX* (where XXX is the class). 2643 const ObjCInterfaceDecl *D = ME->getReceiverInterface(); 2644 return !D ? RetTy : 2645 Ctx.getObjCObjectPointerType(Ctx.getObjCInterfaceType(D)); 2646 } 2647 2648 return RetTy; 2649} 2650 2651void RetainCountChecker::checkSummary(const RetainSummary &Summ, 2652 const CallOrObjCMessage &CallOrMsg, 2653 CheckerContext &C) const { 2654 const ProgramState *state = C.getState(); 2655 2656 // Evaluate the effect of the arguments. 2657 RefVal::Kind hasErr = (RefVal::Kind) 0; 2658 SourceRange ErrorRange; 2659 SymbolRef ErrorSym = 0; 2660 2661 for (unsigned idx = 0, e = CallOrMsg.getNumArgs(); idx != e; ++idx) { 2662 SVal V = CallOrMsg.getArgSVal(idx); 2663 2664 if (SymbolRef Sym = V.getAsLocSymbol()) { 2665 if (RefBindings::data_type *T = state->get<RefBindings>(Sym)) { 2666 state = updateSymbol(state, Sym, *T, Summ.getArg(idx), hasErr, C); 2667 if (hasErr) { 2668 ErrorRange = CallOrMsg.getArgSourceRange(idx); 2669 ErrorSym = Sym; 2670 break; 2671 } 2672 } 2673 } 2674 } 2675 2676 // Evaluate the effect on the message receiver. 2677 bool ReceiverIsTracked = false; 2678 if (!hasErr && CallOrMsg.isObjCMessage()) { 2679 const LocationContext *LC = C.getPredecessor()->getLocationContext(); 2680 SVal Receiver = CallOrMsg.getInstanceMessageReceiver(LC); 2681 if (SymbolRef Sym = Receiver.getAsLocSymbol()) { 2682 if (const RefVal *T = state->get<RefBindings>(Sym)) { 2683 ReceiverIsTracked = true; 2684 state = updateSymbol(state, Sym, *T, Summ.getReceiverEffect(), 2685 hasErr, C); 2686 if (hasErr) { 2687 ErrorRange = CallOrMsg.getReceiverSourceRange(); 2688 ErrorSym = Sym; 2689 } 2690 } 2691 } 2692 } 2693 2694 // Process any errors. 2695 if (hasErr) { 2696 processNonLeakError(state, ErrorRange, hasErr, ErrorSym, C); 2697 return; 2698 } 2699 2700 // Consult the summary for the return value. 2701 RetEffect RE = Summ.getRetEffect(); 2702 2703 if (RE.getKind() == RetEffect::OwnedWhenTrackedReceiver) { 2704 if (ReceiverIsTracked) 2705 RE = getSummaryManager(C).getObjAllocRetEffect(); 2706 else 2707 RE = RetEffect::MakeNoRet(); 2708 } 2709 2710 switch (RE.getKind()) { 2711 default: 2712 llvm_unreachable("Unhandled RetEffect."); break; 2713 2714 case RetEffect::NoRet: 2715 // No work necessary. 2716 break; 2717 2718 case RetEffect::OwnedAllocatedSymbol: 2719 case RetEffect::OwnedSymbol: { 2720 SymbolRef Sym = state->getSVal(CallOrMsg.getOriginExpr()).getAsSymbol(); 2721 if (!Sym) 2722 break; 2723 2724 // Use the result type from callOrMsg as it automatically adjusts 2725 // for methods/functions that return references. 2726 QualType ResultTy = CallOrMsg.getResultType(C.getASTContext()); 2727 state = state->set<RefBindings>(Sym, RefVal::makeOwned(RE.getObjKind(), 2728 ResultTy)); 2729 2730 // FIXME: Add a flag to the checker where allocations are assumed to 2731 // *not* fail. (The code below is out-of-date, though.) 2732#if 0 2733 if (RE.getKind() == RetEffect::OwnedAllocatedSymbol) { 2734 bool isFeasible; 2735 state = state.assume(loc::SymbolVal(Sym), true, isFeasible); 2736 assert(isFeasible && "Cannot assume fresh symbol is non-null."); 2737 } 2738#endif 2739 2740 break; 2741 } 2742 2743 case RetEffect::GCNotOwnedSymbol: 2744 case RetEffect::ARCNotOwnedSymbol: 2745 case RetEffect::NotOwnedSymbol: { 2746 const Expr *Ex = CallOrMsg.getOriginExpr(); 2747 SymbolRef Sym = state->getSVal(Ex).getAsSymbol(); 2748 if (!Sym) 2749 break; 2750 2751 // Use GetReturnType in order to give [NSFoo alloc] the type NSFoo *. 2752 QualType ResultTy = GetReturnType(Ex, C.getASTContext()); 2753 state = state->set<RefBindings>(Sym, RefVal::makeNotOwned(RE.getObjKind(), 2754 ResultTy)); 2755 break; 2756 } 2757 } 2758 2759 // This check is actually necessary; otherwise the statement builder thinks 2760 // we've hit a previously-found path. 2761 // Normally addTransition takes care of this, but we want the node pointer. 2762 ExplodedNode *NewNode; 2763 if (state == C.getState()) { 2764 NewNode = C.getPredecessor(); 2765 } else { 2766 NewNode = C.generateNode(state); 2767 } 2768 2769 // Annotate the node with summary we used. 2770 if (NewNode) { 2771 // FIXME: This is ugly. See checkEndAnalysis for why it's necessary. 2772 if (ShouldResetSummaryLog) { 2773 SummaryLog.clear(); 2774 ShouldResetSummaryLog = false; 2775 } 2776 SummaryLog[NewNode] = &Summ; 2777 } 2778} 2779 2780 2781const ProgramState * 2782RetainCountChecker::updateSymbol(const ProgramState *state, SymbolRef sym, 2783 RefVal V, ArgEffect E, RefVal::Kind &hasErr, 2784 CheckerContext &C) const { 2785 // In GC mode [... release] and [... retain] do nothing. 2786 // In ARC mode they shouldn't exist at all, but we just ignore them. 2787 bool IgnoreRetainMsg = C.isObjCGCEnabled(); 2788 if (!IgnoreRetainMsg) 2789 IgnoreRetainMsg = (bool)C.getASTContext().getLangOptions().ObjCAutoRefCount; 2790 2791 switch (E) { 2792 default: break; 2793 case IncRefMsg: E = IgnoreRetainMsg ? DoNothing : IncRef; break; 2794 case DecRefMsg: E = IgnoreRetainMsg ? DoNothing : DecRef; break; 2795 case MakeCollectable: E = C.isObjCGCEnabled() ? DecRef : DoNothing; break; 2796 case NewAutoreleasePool: E = C.isObjCGCEnabled() ? DoNothing : 2797 NewAutoreleasePool; break; 2798 } 2799 2800 // Handle all use-after-releases. 2801 if (!C.isObjCGCEnabled() && V.getKind() == RefVal::Released) { 2802 V = V ^ RefVal::ErrorUseAfterRelease; 2803 hasErr = V.getKind(); 2804 return state->set<RefBindings>(sym, V); 2805 } 2806 2807 switch (E) { 2808 case DecRefMsg: 2809 case IncRefMsg: 2810 case MakeCollectable: 2811 llvm_unreachable("DecRefMsg/IncRefMsg/MakeCollectable already converted"); 2812 return state; 2813 2814 case Dealloc: 2815 // Any use of -dealloc in GC is *bad*. 2816 if (C.isObjCGCEnabled()) { 2817 V = V ^ RefVal::ErrorDeallocGC; 2818 hasErr = V.getKind(); 2819 break; 2820 } 2821 2822 switch (V.getKind()) { 2823 default: 2824 llvm_unreachable("Invalid RefVal state for an explicit dealloc."); 2825 break; 2826 case RefVal::Owned: 2827 // The object immediately transitions to the released state. 2828 V = V ^ RefVal::Released; 2829 V.clearCounts(); 2830 return state->set<RefBindings>(sym, V); 2831 case RefVal::NotOwned: 2832 V = V ^ RefVal::ErrorDeallocNotOwned; 2833 hasErr = V.getKind(); 2834 break; 2835 } 2836 break; 2837 2838 case NewAutoreleasePool: 2839 assert(!C.isObjCGCEnabled()); 2840 return state->add<AutoreleaseStack>(sym); 2841 2842 case MayEscape: 2843 if (V.getKind() == RefVal::Owned) { 2844 V = V ^ RefVal::NotOwned; 2845 break; 2846 } 2847 2848 // Fall-through. 2849 2850 case DoNothing: 2851 return state; 2852 2853 case Autorelease: 2854 if (C.isObjCGCEnabled()) 2855 return state; 2856 2857 // Update the autorelease counts. 2858 state = SendAutorelease(state, ARCountFactory, sym); 2859 V = V.autorelease(); 2860 break; 2861 2862 case StopTracking: 2863 return state->remove<RefBindings>(sym); 2864 2865 case IncRef: 2866 switch (V.getKind()) { 2867 default: 2868 llvm_unreachable("Invalid RefVal state for a retain."); 2869 break; 2870 case RefVal::Owned: 2871 case RefVal::NotOwned: 2872 V = V + 1; 2873 break; 2874 case RefVal::Released: 2875 // Non-GC cases are handled above. 2876 assert(C.isObjCGCEnabled()); 2877 V = (V ^ RefVal::Owned) + 1; 2878 break; 2879 } 2880 break; 2881 2882 case SelfOwn: 2883 V = V ^ RefVal::NotOwned; 2884 // Fall-through. 2885 case DecRef: 2886 case DecRefBridgedTransfered: 2887 switch (V.getKind()) { 2888 default: 2889 // case 'RefVal::Released' handled above. 2890 llvm_unreachable("Invalid RefVal state for a release."); 2891 break; 2892 2893 case RefVal::Owned: 2894 assert(V.getCount() > 0); 2895 if (V.getCount() == 1) 2896 V = V ^ (E == DecRefBridgedTransfered ? 2897 RefVal::NotOwned : RefVal::Released); 2898 V = V - 1; 2899 break; 2900 2901 case RefVal::NotOwned: 2902 if (V.getCount() > 0) 2903 V = V - 1; 2904 else { 2905 V = V ^ RefVal::ErrorReleaseNotOwned; 2906 hasErr = V.getKind(); 2907 } 2908 break; 2909 2910 case RefVal::Released: 2911 // Non-GC cases are handled above. 2912 assert(C.isObjCGCEnabled()); 2913 V = V ^ RefVal::ErrorUseAfterRelease; 2914 hasErr = V.getKind(); 2915 break; 2916 } 2917 break; 2918 } 2919 return state->set<RefBindings>(sym, V); 2920} 2921 2922void RetainCountChecker::processNonLeakError(const ProgramState *St, 2923 SourceRange ErrorRange, 2924 RefVal::Kind ErrorKind, 2925 SymbolRef Sym, 2926 CheckerContext &C) const { 2927 ExplodedNode *N = C.generateSink(St); 2928 if (!N) 2929 return; 2930 2931 CFRefBug *BT; 2932 switch (ErrorKind) { 2933 default: 2934 llvm_unreachable("Unhandled error."); 2935 return; 2936 case RefVal::ErrorUseAfterRelease: 2937 if (!useAfterRelease) 2938 useAfterRelease.reset(new UseAfterRelease()); 2939 BT = &*useAfterRelease; 2940 break; 2941 case RefVal::ErrorReleaseNotOwned: 2942 if (!releaseNotOwned) 2943 releaseNotOwned.reset(new BadRelease()); 2944 BT = &*releaseNotOwned; 2945 break; 2946 case RefVal::ErrorDeallocGC: 2947 if (!deallocGC) 2948 deallocGC.reset(new DeallocGC()); 2949 BT = &*deallocGC; 2950 break; 2951 case RefVal::ErrorDeallocNotOwned: 2952 if (!deallocNotOwned) 2953 deallocNotOwned.reset(new DeallocNotOwned()); 2954 BT = &*deallocNotOwned; 2955 break; 2956 } 2957 2958 assert(BT); 2959 CFRefReport *report = new CFRefReport(*BT, C.getASTContext().getLangOptions(), 2960 C.isObjCGCEnabled(), SummaryLog, 2961 N, Sym); 2962 report->addRange(ErrorRange); 2963 C.EmitReport(report); 2964} 2965 2966//===----------------------------------------------------------------------===// 2967// Handle the return values of retain-count-related functions. 2968//===----------------------------------------------------------------------===// 2969 2970bool RetainCountChecker::evalCall(const CallExpr *CE, CheckerContext &C) const { 2971 // Get the callee. We're only interested in simple C functions. 2972 const ProgramState *state = C.getState(); 2973 const Expr *Callee = CE->getCallee(); 2974 SVal L = state->getSVal(Callee); 2975 2976 const FunctionDecl *FD = L.getAsFunctionDecl(); 2977 if (!FD) 2978 return false; 2979 2980 IdentifierInfo *II = FD->getIdentifier(); 2981 if (!II) 2982 return false; 2983 2984 // For now, we're only handling the functions that return aliases of their 2985 // arguments: CFRetain and CFMakeCollectable (and their families). 2986 // Eventually we should add other functions we can model entirely, 2987 // such as CFRelease, which don't invalidate their arguments or globals. 2988 if (CE->getNumArgs() != 1) 2989 return false; 2990 2991 // Get the name of the function. 2992 StringRef FName = II->getName(); 2993 FName = FName.substr(FName.find_first_not_of('_')); 2994 2995 // See if it's one of the specific functions we know how to eval. 2996 bool canEval = false; 2997 2998 QualType ResultTy = FD->getResultType(); 2999 if (ResultTy->isObjCIdType()) { 3000 // Handle: id NSMakeCollectable(CFTypeRef) 3001 canEval = II->isStr("NSMakeCollectable"); 3002 } else if (ResultTy->isPointerType()) { 3003 // Handle: (CF|CG)Retain 3004 // CFMakeCollectable 3005 // It's okay to be a little sloppy here (CGMakeCollectable doesn't exist). 3006 if (cocoa::isRefType(ResultTy, "CF", FName) || 3007 cocoa::isRefType(ResultTy, "CG", FName)) { 3008 canEval = isRetain(FD, FName) || isMakeCollectable(FD, FName); 3009 } 3010 } 3011 3012 if (!canEval) 3013 return false; 3014 3015 // Bind the return value. 3016 SVal RetVal = state->getSVal(CE->getArg(0)); 3017 if (RetVal.isUnknown()) { 3018 // If the receiver is unknown, conjure a return value. 3019 SValBuilder &SVB = C.getSValBuilder(); 3020 unsigned Count = C.getNodeBuilder().getCurrentBlockCount(); 3021 SVal RetVal = SVB.getConjuredSymbolVal(0, CE, ResultTy, Count); 3022 } 3023 state = state->BindExpr(CE, RetVal, false); 3024 3025 // FIXME: This should not be necessary, but otherwise the argument seems to be 3026 // considered alive during the next statement. 3027 if (const MemRegion *ArgRegion = RetVal.getAsRegion()) { 3028 // Save the refcount status of the argument. 3029 SymbolRef Sym = RetVal.getAsLocSymbol(); 3030 RefBindings::data_type *Binding = 0; 3031 if (Sym) 3032 Binding = state->get<RefBindings>(Sym); 3033 3034 // Invalidate the argument region. 3035 unsigned Count = C.getNodeBuilder().getCurrentBlockCount(); 3036 state = state->invalidateRegions(ArgRegion, CE, Count); 3037 3038 // Restore the refcount status of the argument. 3039 if (Binding) 3040 state = state->set<RefBindings>(Sym, *Binding); 3041 } 3042 3043 C.addTransition(state); 3044 return true; 3045} 3046 3047//===----------------------------------------------------------------------===// 3048// Handle return statements. 3049//===----------------------------------------------------------------------===// 3050 3051void RetainCountChecker::checkPreStmt(const ReturnStmt *S, 3052 CheckerContext &C) const { 3053 const Expr *RetE = S->getRetValue(); 3054 if (!RetE) 3055 return; 3056 3057 const ProgramState *state = C.getState(); 3058 SymbolRef Sym = state->getSValAsScalarOrLoc(RetE).getAsLocSymbol(); 3059 if (!Sym) 3060 return; 3061 3062 // Get the reference count binding (if any). 3063 const RefVal *T = state->get<RefBindings>(Sym); 3064 if (!T) 3065 return; 3066 3067 // Change the reference count. 3068 RefVal X = *T; 3069 3070 switch (X.getKind()) { 3071 case RefVal::Owned: { 3072 unsigned cnt = X.getCount(); 3073 assert(cnt > 0); 3074 X.setCount(cnt - 1); 3075 X = X ^ RefVal::ReturnedOwned; 3076 break; 3077 } 3078 3079 case RefVal::NotOwned: { 3080 unsigned cnt = X.getCount(); 3081 if (cnt) { 3082 X.setCount(cnt - 1); 3083 X = X ^ RefVal::ReturnedOwned; 3084 } 3085 else { 3086 X = X ^ RefVal::ReturnedNotOwned; 3087 } 3088 break; 3089 } 3090 3091 default: 3092 return; 3093 } 3094 3095 // Update the binding. 3096 state = state->set<RefBindings>(Sym, X); 3097 ExplodedNode *Pred = C.generateNode(state); 3098 3099 // At this point we have updated the state properly. 3100 // Everything after this is merely checking to see if the return value has 3101 // been over- or under-retained. 3102 3103 // Did we cache out? 3104 if (!Pred) 3105 return; 3106 3107 // Update the autorelease counts. 3108 static SimpleProgramPointTag 3109 AutoreleaseTag("RetainCountChecker : Autorelease"); 3110 GenericNodeBuilderRefCount Bd(C.getNodeBuilder(), S, &AutoreleaseTag); 3111 llvm::tie(Pred, state) = handleAutoreleaseCounts(state, Bd, Pred, 3112 C.getEngine(), Sym, X); 3113 3114 // Did we cache out? 3115 if (!Pred) 3116 return; 3117 3118 // Get the updated binding. 3119 T = state->get<RefBindings>(Sym); 3120 assert(T); 3121 X = *T; 3122 3123 // Consult the summary of the enclosing method. 3124 RetainSummaryManager &Summaries = getSummaryManager(C); 3125 const Decl *CD = &Pred->getCodeDecl(); 3126 3127 if (const ObjCMethodDecl *MD = dyn_cast<ObjCMethodDecl>(CD)) { 3128 // Unlike regular functions, /all/ ObjC methods are assumed to always 3129 // follow Cocoa retain-count conventions, not just those with special 3130 // names or attributes. 3131 const RetainSummary *Summ = Summaries.getMethodSummary(MD); 3132 RetEffect RE = Summ ? Summ->getRetEffect() : RetEffect::MakeNoRet(); 3133 checkReturnWithRetEffect(S, C, Pred, RE, X, Sym, state); 3134 } 3135 3136 if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(CD)) { 3137 if (!isa<CXXMethodDecl>(FD)) 3138 if (const RetainSummary *Summ = Summaries.getSummary(FD)) 3139 checkReturnWithRetEffect(S, C, Pred, Summ->getRetEffect(), X, 3140 Sym, state); 3141 } 3142} 3143 3144void RetainCountChecker::checkReturnWithRetEffect(const ReturnStmt *S, 3145 CheckerContext &C, 3146 ExplodedNode *Pred, 3147 RetEffect RE, RefVal X, 3148 SymbolRef Sym, 3149 const ProgramState *state) const { 3150 // Any leaks or other errors? 3151 if (X.isReturnedOwned() && X.getCount() == 0) { 3152 if (RE.getKind() != RetEffect::NoRet) { 3153 bool hasError = false; 3154 if (C.isObjCGCEnabled() && RE.getObjKind() == RetEffect::ObjC) { 3155 // Things are more complicated with garbage collection. If the 3156 // returned object is suppose to be an Objective-C object, we have 3157 // a leak (as the caller expects a GC'ed object) because no 3158 // method should return ownership unless it returns a CF object. 3159 hasError = true; 3160 X = X ^ RefVal::ErrorGCLeakReturned; 3161 } 3162 else if (!RE.isOwned()) { 3163 // Either we are using GC and the returned object is a CF type 3164 // or we aren't using GC. In either case, we expect that the 3165 // enclosing method is expected to return ownership. 3166 hasError = true; 3167 X = X ^ RefVal::ErrorLeakReturned; 3168 } 3169 3170 if (hasError) { 3171 // Generate an error node. 3172 state = state->set<RefBindings>(Sym, X); 3173 StmtNodeBuilder &Builder = C.getNodeBuilder(); 3174 3175 static SimpleProgramPointTag 3176 ReturnOwnLeakTag("RetainCountChecker : ReturnsOwnLeak"); 3177 ExplodedNode *N = Builder.generateNode(S, state, Pred, 3178 &ReturnOwnLeakTag); 3179 if (N) { 3180 const LangOptions &LOpts = C.getASTContext().getLangOptions(); 3181 bool GCEnabled = C.isObjCGCEnabled(); 3182 CFRefReport *report = 3183 new CFRefLeakReport(*getLeakAtReturnBug(LOpts, GCEnabled), 3184 LOpts, GCEnabled, SummaryLog, 3185 N, Sym, C.getEngine()); 3186 C.EmitReport(report); 3187 } 3188 } 3189 } 3190 } else if (X.isReturnedNotOwned()) { 3191 if (RE.isOwned()) { 3192 // Trying to return a not owned object to a caller expecting an 3193 // owned object. 3194 state = state->set<RefBindings>(Sym, X ^ RefVal::ErrorReturnedNotOwned); 3195 StmtNodeBuilder &Builder = C.getNodeBuilder(); 3196 3197 static SimpleProgramPointTag 3198 ReturnNotOwnedTag("RetainCountChecker : ReturnNotOwnedForOwned"); 3199 ExplodedNode *N = Builder.generateNode(S, state, Pred, 3200 &ReturnNotOwnedTag); 3201 if (N) { 3202 if (!returnNotOwnedForOwned) 3203 returnNotOwnedForOwned.reset(new ReturnedNotOwnedForOwned()); 3204 3205 CFRefReport *report = 3206 new CFRefReport(*returnNotOwnedForOwned, 3207 C.getASTContext().getLangOptions(), 3208 C.isObjCGCEnabled(), SummaryLog, N, Sym); 3209 C.EmitReport(report); 3210 } 3211 } 3212 } 3213} 3214 3215//===----------------------------------------------------------------------===// 3216// Check various ways a symbol can be invalidated. 3217//===----------------------------------------------------------------------===// 3218 3219void RetainCountChecker::checkBind(SVal loc, SVal val, 3220 CheckerContext &C) const { 3221 // Are we storing to something that causes the value to "escape"? 3222 bool escapes = true; 3223 3224 // A value escapes in three possible cases (this may change): 3225 // 3226 // (1) we are binding to something that is not a memory region. 3227 // (2) we are binding to a memregion that does not have stack storage 3228 // (3) we are binding to a memregion with stack storage that the store 3229 // does not understand. 3230 const ProgramState *state = C.getState(); 3231 3232 if (loc::MemRegionVal *regionLoc = dyn_cast<loc::MemRegionVal>(&loc)) { 3233 escapes = !regionLoc->getRegion()->hasStackStorage(); 3234 3235 if (!escapes) { 3236 // To test (3), generate a new state with the binding added. If it is 3237 // the same state, then it escapes (since the store cannot represent 3238 // the binding). 3239 escapes = (state == (state->bindLoc(*regionLoc, val))); 3240 } 3241 } 3242 3243 // If our store can represent the binding and we aren't storing to something 3244 // that doesn't have local storage then just return and have the simulation 3245 // state continue as is. 3246 if (!escapes) 3247 return; 3248 3249 // Otherwise, find all symbols referenced by 'val' that we are tracking 3250 // and stop tracking them. 3251 state = state->scanReachableSymbols<StopTrackingCallback>(val).getState(); 3252 C.addTransition(state); 3253} 3254 3255const ProgramState *RetainCountChecker::evalAssume(const ProgramState *state, 3256 SVal Cond, 3257 bool Assumption) const { 3258 3259 // FIXME: We may add to the interface of evalAssume the list of symbols 3260 // whose assumptions have changed. For now we just iterate through the 3261 // bindings and check if any of the tracked symbols are NULL. This isn't 3262 // too bad since the number of symbols we will track in practice are 3263 // probably small and evalAssume is only called at branches and a few 3264 // other places. 3265 RefBindings B = state->get<RefBindings>(); 3266 3267 if (B.isEmpty()) 3268 return state; 3269 3270 bool changed = false; 3271 RefBindings::Factory &RefBFactory = state->get_context<RefBindings>(); 3272 3273 for (RefBindings::iterator I = B.begin(), E = B.end(); I != E; ++I) { 3274 // Check if the symbol is null (or equal to any constant). 3275 // If this is the case, stop tracking the symbol. 3276 if (state->getSymVal(I.getKey())) { 3277 changed = true; 3278 B = RefBFactory.remove(B, I.getKey()); 3279 } 3280 } 3281 3282 if (changed) 3283 state = state->set<RefBindings>(B); 3284 3285 return state; 3286} 3287 3288const ProgramState * 3289RetainCountChecker::checkRegionChanges(const ProgramState *state, 3290 const StoreManager::InvalidatedSymbols *invalidated, 3291 ArrayRef<const MemRegion *> ExplicitRegions, 3292 ArrayRef<const MemRegion *> Regions) const { 3293 if (!invalidated) 3294 return state; 3295 3296 llvm::SmallPtrSet<SymbolRef, 8> WhitelistedSymbols; 3297 for (ArrayRef<const MemRegion *>::iterator I = ExplicitRegions.begin(), 3298 E = ExplicitRegions.end(); I != E; ++I) { 3299 if (const SymbolicRegion *SR = (*I)->StripCasts()->getAs<SymbolicRegion>()) 3300 WhitelistedSymbols.insert(SR->getSymbol()); 3301 } 3302 3303 for (StoreManager::InvalidatedSymbols::const_iterator I=invalidated->begin(), 3304 E = invalidated->end(); I!=E; ++I) { 3305 SymbolRef sym = *I; 3306 if (WhitelistedSymbols.count(sym)) 3307 continue; 3308 // Remove any existing reference-count binding. 3309 state = state->remove<RefBindings>(sym); 3310 } 3311 return state; 3312} 3313 3314//===----------------------------------------------------------------------===// 3315// Handle dead symbols and end-of-path. 3316//===----------------------------------------------------------------------===// 3317 3318std::pair<ExplodedNode *, const ProgramState *> 3319RetainCountChecker::handleAutoreleaseCounts(const ProgramState *state, 3320 GenericNodeBuilderRefCount Bd, 3321 ExplodedNode *Pred, ExprEngine &Eng, 3322 SymbolRef Sym, RefVal V) const { 3323 unsigned ACnt = V.getAutoreleaseCount(); 3324 3325 // No autorelease counts? Nothing to be done. 3326 if (!ACnt) 3327 return std::make_pair(Pred, state); 3328 3329 assert(!Eng.isObjCGCEnabled() && "Autorelease counts in GC mode?"); 3330 unsigned Cnt = V.getCount(); 3331 3332 // FIXME: Handle sending 'autorelease' to already released object. 3333 3334 if (V.getKind() == RefVal::ReturnedOwned) 3335 ++Cnt; 3336 3337 if (ACnt <= Cnt) { 3338 if (ACnt == Cnt) { 3339 V.clearCounts(); 3340 if (V.getKind() == RefVal::ReturnedOwned) 3341 V = V ^ RefVal::ReturnedNotOwned; 3342 else 3343 V = V ^ RefVal::NotOwned; 3344 } else { 3345 V.setCount(Cnt - ACnt); 3346 V.setAutoreleaseCount(0); 3347 } 3348 state = state->set<RefBindings>(Sym, V); 3349 ExplodedNode *N = Bd.MakeNode(state, Pred); 3350 if (N == 0) 3351 state = 0; 3352 return std::make_pair(N, state); 3353 } 3354 3355 // Woah! More autorelease counts then retain counts left. 3356 // Emit hard error. 3357 V = V ^ RefVal::ErrorOverAutorelease; 3358 state = state->set<RefBindings>(Sym, V); 3359 3360 if (ExplodedNode *N = Bd.MakeNode(state, Pred)) { 3361 N->markAsSink(); 3362 3363 llvm::SmallString<128> sbuf; 3364 llvm::raw_svector_ostream os(sbuf); 3365 os << "Object over-autoreleased: object was sent -autorelease "; 3366 if (V.getAutoreleaseCount() > 1) 3367 os << V.getAutoreleaseCount() << " times "; 3368 os << "but the object has a +" << V.getCount() << " retain count"; 3369 3370 if (!overAutorelease) 3371 overAutorelease.reset(new OverAutorelease()); 3372 3373 const LangOptions &LOpts = Eng.getContext().getLangOptions(); 3374 CFRefReport *report = 3375 new CFRefReport(*overAutorelease, LOpts, /* GCEnabled = */ false, 3376 SummaryLog, N, Sym, os.str()); 3377 Eng.getBugReporter().EmitReport(report); 3378 } 3379 3380 return std::make_pair((ExplodedNode *)0, (const ProgramState *)0); 3381} 3382 3383const ProgramState * 3384RetainCountChecker::handleSymbolDeath(const ProgramState *state, 3385 SymbolRef sid, RefVal V, 3386 SmallVectorImpl<SymbolRef> &Leaked) const { 3387 bool hasLeak = false; 3388 if (V.isOwned()) 3389 hasLeak = true; 3390 else if (V.isNotOwned() || V.isReturnedOwned()) 3391 hasLeak = (V.getCount() > 0); 3392 3393 if (!hasLeak) 3394 return state->remove<RefBindings>(sid); 3395 3396 Leaked.push_back(sid); 3397 return state->set<RefBindings>(sid, V ^ RefVal::ErrorLeak); 3398} 3399 3400ExplodedNode * 3401RetainCountChecker::processLeaks(const ProgramState *state, 3402 SmallVectorImpl<SymbolRef> &Leaked, 3403 GenericNodeBuilderRefCount &Builder, 3404 ExprEngine &Eng, ExplodedNode *Pred) const { 3405 if (Leaked.empty()) 3406 return Pred; 3407 3408 // Generate an intermediate node representing the leak point. 3409 ExplodedNode *N = Builder.MakeNode(state, Pred); 3410 3411 if (N) { 3412 for (SmallVectorImpl<SymbolRef>::iterator 3413 I = Leaked.begin(), E = Leaked.end(); I != E; ++I) { 3414 3415 const LangOptions &LOpts = Eng.getContext().getLangOptions(); 3416 bool GCEnabled = Eng.isObjCGCEnabled(); 3417 CFRefBug *BT = Pred ? getLeakWithinFunctionBug(LOpts, GCEnabled) 3418 : getLeakAtReturnBug(LOpts, GCEnabled); 3419 assert(BT && "BugType not initialized."); 3420 3421 CFRefLeakReport *report = new CFRefLeakReport(*BT, LOpts, GCEnabled, 3422 SummaryLog, N, *I, Eng); 3423 Eng.getBugReporter().EmitReport(report); 3424 } 3425 } 3426 3427 return N; 3428} 3429 3430void RetainCountChecker::checkEndPath(EndOfFunctionNodeBuilder &Builder, 3431 ExprEngine &Eng) const { 3432 const ProgramState *state = Builder.getState(); 3433 GenericNodeBuilderRefCount Bd(Builder); 3434 RefBindings B = state->get<RefBindings>(); 3435 ExplodedNode *Pred = 0; 3436 3437 for (RefBindings::iterator I = B.begin(), E = B.end(); I != E; ++I) { 3438 llvm::tie(Pred, state) = handleAutoreleaseCounts(state, Bd, Pred, Eng, 3439 I->first, I->second); 3440 if (!state) 3441 return; 3442 } 3443 3444 B = state->get<RefBindings>(); 3445 SmallVector<SymbolRef, 10> Leaked; 3446 3447 for (RefBindings::iterator I = B.begin(), E = B.end(); I != E; ++I) 3448 state = handleSymbolDeath(state, I->first, I->second, Leaked); 3449 3450 processLeaks(state, Leaked, Bd, Eng, Pred); 3451} 3452 3453const ProgramPointTag * 3454RetainCountChecker::getDeadSymbolTag(SymbolRef sym) const { 3455 const SimpleProgramPointTag *&tag = DeadSymbolTags[sym]; 3456 if (!tag) { 3457 llvm::SmallString<64> buf; 3458 llvm::raw_svector_ostream out(buf); 3459 out << "RetainCountChecker : Dead Symbol : " << sym->getSymbolID(); 3460 tag = new SimpleProgramPointTag(out.str()); 3461 } 3462 return tag; 3463} 3464 3465void RetainCountChecker::checkDeadSymbols(SymbolReaper &SymReaper, 3466 CheckerContext &C) const { 3467 StmtNodeBuilder &Builder = C.getNodeBuilder(); 3468 ExprEngine &Eng = C.getEngine(); 3469 const Stmt *S = C.getStmt(); 3470 ExplodedNode *Pred = C.getPredecessor(); 3471 3472 const ProgramState *state = C.getState(); 3473 RefBindings B = state->get<RefBindings>(); 3474 3475 // Update counts from autorelease pools 3476 for (SymbolReaper::dead_iterator I = SymReaper.dead_begin(), 3477 E = SymReaper.dead_end(); I != E; ++I) { 3478 SymbolRef Sym = *I; 3479 if (const RefVal *T = B.lookup(Sym)){ 3480 // Use the symbol as the tag. 3481 // FIXME: This might not be as unique as we would like. 3482 GenericNodeBuilderRefCount Bd(Builder, S, getDeadSymbolTag(Sym)); 3483 llvm::tie(Pred, state) = handleAutoreleaseCounts(state, Bd, Pred, Eng, 3484 Sym, *T); 3485 if (!state) 3486 return; 3487 } 3488 } 3489 3490 B = state->get<RefBindings>(); 3491 SmallVector<SymbolRef, 10> Leaked; 3492 3493 for (SymbolReaper::dead_iterator I = SymReaper.dead_begin(), 3494 E = SymReaper.dead_end(); I != E; ++I) { 3495 if (const RefVal *T = B.lookup(*I)) 3496 state = handleSymbolDeath(state, *I, *T, Leaked); 3497 } 3498 3499 { 3500 GenericNodeBuilderRefCount Bd(Builder, S, this); 3501 Pred = processLeaks(state, Leaked, Bd, Eng, Pred); 3502 } 3503 3504 // Did we cache out? 3505 if (!Pred) 3506 return; 3507 3508 // Now generate a new node that nukes the old bindings. 3509 RefBindings::Factory &F = state->get_context<RefBindings>(); 3510 3511 for (SymbolReaper::dead_iterator I = SymReaper.dead_begin(), 3512 E = SymReaper.dead_end(); I != E; ++I) 3513 B = F.remove(B, *I); 3514 3515 state = state->set<RefBindings>(B); 3516 C.generateNode(state, Pred); 3517} 3518 3519//===----------------------------------------------------------------------===// 3520// Debug printing of refcount bindings and autorelease pools. 3521//===----------------------------------------------------------------------===// 3522 3523static void PrintPool(raw_ostream &Out, SymbolRef Sym, 3524 const ProgramState *State) { 3525 Out << ' '; 3526 if (Sym) 3527 Out << Sym->getSymbolID(); 3528 else 3529 Out << "<pool>"; 3530 Out << ":{"; 3531 3532 // Get the contents of the pool. 3533 if (const ARCounts *Cnts = State->get<AutoreleasePoolContents>(Sym)) 3534 for (ARCounts::iterator I = Cnts->begin(), E = Cnts->end(); I != E; ++I) 3535 Out << '(' << I.getKey() << ',' << I.getData() << ')'; 3536 3537 Out << '}'; 3538} 3539 3540static bool UsesAutorelease(const ProgramState *state) { 3541 // A state uses autorelease if it allocated an autorelease pool or if it has 3542 // objects in the caller's autorelease pool. 3543 return !state->get<AutoreleaseStack>().isEmpty() || 3544 state->get<AutoreleasePoolContents>(SymbolRef()); 3545} 3546 3547void RetainCountChecker::printState(raw_ostream &Out, const ProgramState *State, 3548 const char *NL, const char *Sep) const { 3549 3550 RefBindings B = State->get<RefBindings>(); 3551 3552 if (!B.isEmpty()) 3553 Out << Sep << NL; 3554 3555 for (RefBindings::iterator I = B.begin(), E = B.end(); I != E; ++I) { 3556 Out << I->first << " : "; 3557 I->second.print(Out); 3558 Out << NL; 3559 } 3560 3561 // Print the autorelease stack. 3562 if (UsesAutorelease(State)) { 3563 Out << Sep << NL << "AR pool stack:"; 3564 ARStack Stack = State->get<AutoreleaseStack>(); 3565 3566 PrintPool(Out, SymbolRef(), State); // Print the caller's pool. 3567 for (ARStack::iterator I = Stack.begin(), E = Stack.end(); I != E; ++I) 3568 PrintPool(Out, *I, State); 3569 3570 Out << NL; 3571 } 3572} 3573 3574//===----------------------------------------------------------------------===// 3575// Checker registration. 3576//===----------------------------------------------------------------------===// 3577 3578void ento::registerRetainCountChecker(CheckerManager &Mgr) { 3579 Mgr.registerChecker<RetainCountChecker>(); 3580} 3581 3582