// CFRefCount.cpp - Transfer functions for tracking simple values -*- C++ -*--// // // The LLVM Compiler Infrastructure // // This file is distributed under the University of Illinois Open Source // License. See LICENSE.TXT for details. // //===----------------------------------------------------------------------===// // // This file defines the methods for CFRefCount, which implements // a reference count checker for Core Foundation (Mac OS X). // //===----------------------------------------------------------------------===// #include "GRSimpleVals.h" #include "clang/Basic/LangOptions.h" #include "clang/Basic/SourceManager.h" #include "clang/Analysis/PathSensitive/GRState.h" #include "clang/Analysis/PathSensitive/GRStateTrait.h" #include "clang/Analysis/PathDiagnostic.h" #include "clang/Analysis/LocalCheckers.h" #include "clang/Analysis/PathDiagnostic.h" #include "clang/Analysis/PathSensitive/BugReporter.h" #include "clang/AST/DeclObjC.h" #include "llvm/ADT/DenseMap.h" #include "llvm/ADT/FoldingSet.h" #include "llvm/ADT/ImmutableMap.h" #include "llvm/ADT/StringExtras.h" #include "llvm/Support/Compiler.h" #include "llvm/ADT/STLExtras.h" #include #include #include using namespace clang; using llvm::CStrInCStrNoCase; //===----------------------------------------------------------------------===// // Selector creation functions. //===----------------------------------------------------------------------===// static inline Selector GetNullarySelector(const char* name, ASTContext& Ctx) { IdentifierInfo* II = &Ctx.Idents.get(name); return Ctx.Selectors.getSelector(0, &II); } static inline Selector GetUnarySelector(const char* name, ASTContext& Ctx) { IdentifierInfo* II = &Ctx.Idents.get(name); return Ctx.Selectors.getSelector(1, &II); } //===----------------------------------------------------------------------===// // Type querying functions. //===----------------------------------------------------------------------===// static bool isCFRefType(QualType T) { if (!T->isPointerType()) return false; // Check the typedef for the name "CF" and the substring "Ref". TypedefType* TD = dyn_cast(T.getTypePtr()); if (!TD) return false; const char* TDName = TD->getDecl()->getIdentifier()->getName(); assert (TDName); if (TDName[0] != 'C' || TDName[1] != 'F') return false; if (strstr(TDName, "Ref") == 0) return false; return true; } static bool isCGRefType(QualType T) { if (!T->isPointerType()) return false; // Check the typedef for the name "CG" and the substring "Ref". TypedefType* TD = dyn_cast(T.getTypePtr()); if (!TD) return false; const char* TDName = TD->getDecl()->getIdentifier()->getName(); assert (TDName); if (TDName[0] != 'C' || TDName[1] != 'G') return false; if (strstr(TDName, "Ref") == 0) return false; return true; } static bool isNSType(QualType T) { if (!T->isPointerType()) return false; ObjCInterfaceType* OT = dyn_cast(T.getTypePtr()); if (!OT) return false; const char* ClsName = OT->getDecl()->getIdentifier()->getName(); assert (ClsName); if (ClsName[0] != 'N' || ClsName[1] != 'S') return false; return true; } //===----------------------------------------------------------------------===// // Primitives used for constructing summaries for function/method calls. //===----------------------------------------------------------------------===// namespace { /// ArgEffect is used to summarize a function/method call's effect on a /// particular argument. enum ArgEffect { IncRef, DecRef, DoNothing, DoNothingByRef, StopTracking, MayEscape, SelfOwn, Autorelease }; /// ArgEffects summarizes the effects of a function/method call on all of /// its arguments. typedef std::vector > ArgEffects; } namespace llvm { template <> struct FoldingSetTrait { static void Profile(const ArgEffects& X, FoldingSetNodeID& ID) { for (ArgEffects::const_iterator I = X.begin(), E = X.end(); I!= E; ++I) { ID.AddInteger(I->first); ID.AddInteger((unsigned) I->second); } } }; } // end llvm namespace namespace { /// RetEffect is used to summarize a function/method call's behavior with /// respect to its return value. class VISIBILITY_HIDDEN RetEffect { public: enum Kind { NoRet, Alias, OwnedSymbol, OwnedAllocatedSymbol, NotOwnedSymbol, ReceiverAlias }; private: unsigned Data; RetEffect(Kind k, unsigned D = 0) { Data = (D << 3) | (unsigned) k; } public: Kind getKind() const { return (Kind) (Data & 0x7); } unsigned getIndex() const { assert(getKind() == Alias); return Data >> 3; } static RetEffect MakeAlias(unsigned Idx) { return RetEffect(Alias, Idx); } static RetEffect MakeReceiverAlias() { return RetEffect(ReceiverAlias); } static RetEffect MakeOwned(bool isAllocated = false) { return RetEffect(isAllocated ? OwnedAllocatedSymbol : OwnedSymbol); } static RetEffect MakeNotOwned() { return RetEffect(NotOwnedSymbol); } static RetEffect MakeNoRet() { return RetEffect(NoRet); } operator Kind() const { return getKind(); } void Profile(llvm::FoldingSetNodeID& ID) const { ID.AddInteger(Data); } }; class VISIBILITY_HIDDEN RetainSummary : public llvm::FoldingSetNode { /// Args - an ordered vector of (index, ArgEffect) pairs, where index /// specifies the argument (starting from 0). This can be sparsely /// populated; arguments with no entry in Args use 'DefaultArgEffect'. ArgEffects* Args; /// DefaultArgEffect - The default ArgEffect to apply to arguments that /// do not have an entry in Args. ArgEffect DefaultArgEffect; /// Receiver - If this summary applies to an Objective-C message expression, /// this is the effect applied to the state of the receiver. ArgEffect Receiver; /// Ret - The effect on the return value. Used to indicate if the /// function/method call returns a new tracked symbol, returns an /// alias of one of the arguments in the call, and so on. RetEffect Ret; /// EndPath - Indicates that execution of this method/function should /// terminate the simulation of a path. bool EndPath; public: RetainSummary(ArgEffects* A, RetEffect R, ArgEffect defaultEff, ArgEffect ReceiverEff, bool endpath = false) : Args(A), DefaultArgEffect(defaultEff), Receiver(ReceiverEff), Ret(R), EndPath(endpath) {} /// getArg - Return the argument effect on the argument specified by /// idx (starting from 0). ArgEffect getArg(unsigned idx) const { if (!Args) return DefaultArgEffect; // If Args is present, it is likely to contain only 1 element. // Just do a linear search. Do it from the back because functions with // large numbers of arguments will be tail heavy with respect to which // argument they actually modify with respect to the reference count. for (ArgEffects::reverse_iterator I=Args->rbegin(), E=Args->rend(); I!=E; ++I) { if (idx > I->first) return DefaultArgEffect; if (idx == I->first) return I->second; } return DefaultArgEffect; } /// getRetEffect - Returns the effect on the return value of the call. RetEffect getRetEffect() const { return Ret; } /// isEndPath - Returns true if executing the given method/function should /// terminate the path. bool isEndPath() const { return EndPath; } /// getReceiverEffect - Returns the effect on the receiver of the call. /// This is only meaningful if the summary applies to an ObjCMessageExpr*. ArgEffect getReceiverEffect() const { return Receiver; } typedef ArgEffects::const_iterator ExprIterator; ExprIterator begin_args() const { return Args->begin(); } ExprIterator end_args() const { return Args->end(); } static void Profile(llvm::FoldingSetNodeID& ID, ArgEffects* A, RetEffect RetEff, ArgEffect DefaultEff, ArgEffect ReceiverEff, bool EndPath) { ID.AddPointer(A); ID.Add(RetEff); ID.AddInteger((unsigned) DefaultEff); ID.AddInteger((unsigned) ReceiverEff); ID.AddInteger((unsigned) EndPath); } void Profile(llvm::FoldingSetNodeID& ID) const { Profile(ID, Args, Ret, DefaultArgEffect, Receiver, EndPath); } }; } // end anonymous namespace //===----------------------------------------------------------------------===// // Data structures for constructing summaries. //===----------------------------------------------------------------------===// namespace { class VISIBILITY_HIDDEN ObjCSummaryKey { IdentifierInfo* II; Selector S; public: ObjCSummaryKey(IdentifierInfo* ii, Selector s) : II(ii), S(s) {} ObjCSummaryKey(ObjCInterfaceDecl* d, Selector s) : II(d ? d->getIdentifier() : 0), S(s) {} ObjCSummaryKey(Selector s) : II(0), S(s) {} IdentifierInfo* getIdentifier() const { return II; } Selector getSelector() const { return S; } }; } namespace llvm { template <> struct DenseMapInfo { static inline ObjCSummaryKey getEmptyKey() { return ObjCSummaryKey(DenseMapInfo::getEmptyKey(), DenseMapInfo::getEmptyKey()); } static inline ObjCSummaryKey getTombstoneKey() { return ObjCSummaryKey(DenseMapInfo::getTombstoneKey(), DenseMapInfo::getTombstoneKey()); } static unsigned getHashValue(const ObjCSummaryKey &V) { return (DenseMapInfo::getHashValue(V.getIdentifier()) & 0x88888888) | (DenseMapInfo::getHashValue(V.getSelector()) & 0x55555555); } static bool isEqual(const ObjCSummaryKey& LHS, const ObjCSummaryKey& RHS) { return DenseMapInfo::isEqual(LHS.getIdentifier(), RHS.getIdentifier()) && DenseMapInfo::isEqual(LHS.getSelector(), RHS.getSelector()); } static bool isPod() { return DenseMapInfo::isPod() && DenseMapInfo::isPod(); } }; } // end llvm namespace namespace { class VISIBILITY_HIDDEN ObjCSummaryCache { typedef llvm::DenseMap MapTy; MapTy M; public: ObjCSummaryCache() {} typedef MapTy::iterator iterator; iterator find(ObjCInterfaceDecl* D, Selector S) { // Do a lookup with the (D,S) pair. If we find a match return // the iterator. ObjCSummaryKey K(D, S); MapTy::iterator I = M.find(K); if (I != M.end() || !D) return I; // Walk the super chain. If we find a hit with a parent, we'll end // up returning that summary. We actually allow that key (null,S), as // we cache summaries for the null ObjCInterfaceDecl* to allow us to // generate initial summaries without having to worry about NSObject // being declared. // FIXME: We may change this at some point. for (ObjCInterfaceDecl* C=D->getSuperClass() ;; C=C->getSuperClass()) { if ((I = M.find(ObjCSummaryKey(C, S))) != M.end()) break; if (!C) return I; } // Cache the summary with original key to make the next lookup faster // and return the iterator. M[K] = I->second; return I; } iterator find(Expr* Receiver, Selector S) { return find(getReceiverDecl(Receiver), S); } iterator find(IdentifierInfo* II, Selector S) { // FIXME: Class method lookup. Right now we dont' have a good way // of going between IdentifierInfo* and the class hierarchy. iterator I = M.find(ObjCSummaryKey(II, S)); return I == M.end() ? M.find(ObjCSummaryKey(S)) : I; } ObjCInterfaceDecl* getReceiverDecl(Expr* E) { const PointerType* PT = E->getType()->getAsPointerType(); if (!PT) return 0; ObjCInterfaceType* OI = dyn_cast(PT->getPointeeType()); if (!OI) return 0; return OI ? OI->getDecl() : 0; } iterator end() { return M.end(); } RetainSummary*& operator[](ObjCMessageExpr* ME) { Selector S = ME->getSelector(); if (Expr* Receiver = ME->getReceiver()) { ObjCInterfaceDecl* OD = getReceiverDecl(Receiver); return OD ? M[ObjCSummaryKey(OD->getIdentifier(), S)] : M[S]; } return M[ObjCSummaryKey(ME->getClassName(), S)]; } RetainSummary*& operator[](ObjCSummaryKey K) { return M[K]; } RetainSummary*& operator[](Selector S) { return M[ ObjCSummaryKey(S) ]; } }; } // end anonymous namespace //===----------------------------------------------------------------------===// // Data structures for managing collections of summaries. //===----------------------------------------------------------------------===// namespace { class VISIBILITY_HIDDEN RetainSummaryManager { //==-----------------------------------------------------------------==// // Typedefs. //==-----------------------------------------------------------------==// typedef llvm::FoldingSet > ArgEffectsSetTy; typedef llvm::FoldingSet SummarySetTy; typedef llvm::DenseMap FuncSummariesTy; typedef ObjCSummaryCache ObjCMethodSummariesTy; //==-----------------------------------------------------------------==// // Data. //==-----------------------------------------------------------------==// /// Ctx - The ASTContext object for the analyzed ASTs. ASTContext& Ctx; /// CFDictionaryCreateII - An IdentifierInfo* representing the indentifier /// "CFDictionaryCreate". IdentifierInfo* CFDictionaryCreateII; /// GCEnabled - Records whether or not the analyzed code runs in GC mode. const bool GCEnabled; /// SummarySet - A FoldingSet of uniqued summaries. SummarySetTy SummarySet; /// FuncSummaries - A map from FunctionDecls to summaries. FuncSummariesTy FuncSummaries; /// ObjCClassMethodSummaries - A map from selectors (for instance methods) /// to summaries. ObjCMethodSummariesTy ObjCClassMethodSummaries; /// ObjCMethodSummaries - A map from selectors to summaries. ObjCMethodSummariesTy ObjCMethodSummaries; /// ArgEffectsSet - A FoldingSet of uniqued ArgEffects. ArgEffectsSetTy ArgEffectsSet; /// BPAlloc - A BumpPtrAllocator used for allocating summaries, ArgEffects, /// and all other data used by the checker. llvm::BumpPtrAllocator BPAlloc; /// ScratchArgs - A holding buffer for construct ArgEffects. ArgEffects ScratchArgs; RetainSummary* StopSummary; //==-----------------------------------------------------------------==// // Methods. //==-----------------------------------------------------------------==// /// getArgEffects - Returns a persistent ArgEffects object based on the /// data in ScratchArgs. ArgEffects* getArgEffects(); enum UnaryFuncKind { cfretain, cfrelease, cfmakecollectable }; RetainSummary* getUnarySummary(FunctionDecl* FD, UnaryFuncKind func); RetainSummary* getNSSummary(FunctionDecl* FD, const char* FName); RetainSummary* getCFSummary(FunctionDecl* FD, const char* FName); RetainSummary* getCGSummary(FunctionDecl* FD, const char* FName); RetainSummary* getCFSummaryCreateRule(FunctionDecl* FD); RetainSummary* getCFSummaryGetRule(FunctionDecl* FD); RetainSummary* getCFCreateGetRuleSummary(FunctionDecl* FD, const char* FName); RetainSummary* getPersistentSummary(ArgEffects* AE, RetEffect RetEff, ArgEffect ReceiverEff = DoNothing, ArgEffect DefaultEff = MayEscape, bool isEndPath = false); RetainSummary* getPersistentSummary(RetEffect RE, ArgEffect ReceiverEff = DoNothing, ArgEffect DefaultEff = MayEscape) { return getPersistentSummary(getArgEffects(), RE, ReceiverEff, DefaultEff); } RetainSummary* getPersistentStopSummary() { if (StopSummary) return StopSummary; StopSummary = getPersistentSummary(RetEffect::MakeNoRet(), StopTracking, StopTracking); return StopSummary; } RetainSummary* getInitMethodSummary(ObjCMessageExpr* ME); void InitializeClassMethodSummaries(); void InitializeMethodSummaries(); void addClsMethSummary(IdentifierInfo* ClsII, Selector S, RetainSummary* Summ) { ObjCClassMethodSummaries[ObjCSummaryKey(ClsII, S)] = Summ; } void addNSObjectClsMethSummary(Selector S, RetainSummary *Summ) { ObjCClassMethodSummaries[S] = Summ; } void addNSObjectMethSummary(Selector S, RetainSummary *Summ) { ObjCMethodSummaries[S] = Summ; } void addInstMethSummary(const char* Cls, RetainSummary* Summ, va_list argp) { IdentifierInfo* ClsII = &Ctx.Idents.get(Cls); llvm::SmallVector II; while (const char* s = va_arg(argp, const char*)) II.push_back(&Ctx.Idents.get(s)); Selector S = Ctx.Selectors.getSelector(II.size(), &II[0]); ObjCMethodSummaries[ObjCSummaryKey(ClsII, S)] = Summ; } void addInstMethSummary(const char* Cls, RetainSummary* Summ, ...) { va_list argp; va_start(argp, Summ); addInstMethSummary(Cls, Summ, argp); va_end(argp); } void addPanicSummary(const char* Cls, ...) { RetainSummary* Summ = getPersistentSummary(0, RetEffect::MakeNoRet(), DoNothing, DoNothing, true); va_list argp; va_start (argp, Cls); addInstMethSummary(Cls, Summ, argp); va_end(argp); } public: RetainSummaryManager(ASTContext& ctx, bool gcenabled) : Ctx(ctx), CFDictionaryCreateII(&ctx.Idents.get("CFDictionaryCreate")), GCEnabled(gcenabled), StopSummary(0) { InitializeClassMethodSummaries(); InitializeMethodSummaries(); } ~RetainSummaryManager(); RetainSummary* getSummary(FunctionDecl* FD); RetainSummary* getMethodSummary(ObjCMessageExpr* ME, ObjCInterfaceDecl* ID); RetainSummary* getClassMethodSummary(IdentifierInfo* ClsName, Selector S); bool isGCEnabled() const { return GCEnabled; } }; } // end anonymous namespace //===----------------------------------------------------------------------===// // Implementation of checker data structures. //===----------------------------------------------------------------------===// RetainSummaryManager::~RetainSummaryManager() { // FIXME: The ArgEffects could eventually be allocated from BPAlloc, // mitigating the need to do explicit cleanup of the // Argument-Effect summaries. for (ArgEffectsSetTy::iterator I = ArgEffectsSet.begin(), E = ArgEffectsSet.end(); I!=E; ++I) I->getValue().~ArgEffects(); } ArgEffects* RetainSummaryManager::getArgEffects() { if (ScratchArgs.empty()) return NULL; // Compute a profile for a non-empty ScratchArgs. llvm::FoldingSetNodeID profile; profile.Add(ScratchArgs); void* InsertPos; // Look up the uniqued copy, or create a new one. llvm::FoldingSetNodeWrapper* E = ArgEffectsSet.FindNodeOrInsertPos(profile, InsertPos); if (E) { ScratchArgs.clear(); return &E->getValue(); } E = (llvm::FoldingSetNodeWrapper*) BPAlloc.Allocate >(); new (E) llvm::FoldingSetNodeWrapper(ScratchArgs); ArgEffectsSet.InsertNode(E, InsertPos); ScratchArgs.clear(); return &E->getValue(); } RetainSummary* RetainSummaryManager::getPersistentSummary(ArgEffects* AE, RetEffect RetEff, ArgEffect ReceiverEff, ArgEffect DefaultEff, bool isEndPath) { // Generate a profile for the summary. llvm::FoldingSetNodeID profile; RetainSummary::Profile(profile, AE, RetEff, DefaultEff, ReceiverEff, isEndPath); // Look up the uniqued summary, or create one if it doesn't exist. void* InsertPos; RetainSummary* Summ = SummarySet.FindNodeOrInsertPos(profile, InsertPos); if (Summ) return Summ; // Create the summary and return it. Summ = (RetainSummary*) BPAlloc.Allocate(); new (Summ) RetainSummary(AE, RetEff, DefaultEff, ReceiverEff, isEndPath); SummarySet.InsertNode(Summ, InsertPos); return Summ; } //===----------------------------------------------------------------------===// // Summary creation for functions (largely uses of Core Foundation). //===----------------------------------------------------------------------===// RetainSummary* RetainSummaryManager::getSummary(FunctionDecl* FD) { SourceLocation Loc = FD->getLocation(); if (!Loc.isFileID()) return NULL; // Look up a summary in our cache of FunctionDecls -> Summaries. FuncSummariesTy::iterator I = FuncSummaries.find(FD); if (I != FuncSummaries.end()) return I->second; // No summary. Generate one. const char* FName = FD->getIdentifier()->getName(); RetainSummary *S = 0; FunctionType* FT = dyn_cast(FD->getType()); do { if (FT) { QualType T = FT->getResultType(); if (isCFRefType(T)) { S = getCFSummary(FD, FName); break; } if (isCGRefType(T)) { S = getCGSummary(FD, FName ); break; } } if (FName[0] == 'C' && FName[1] == 'F') S = getCFSummary(FD, FName); else if (FName[0] == 'N' && FName[1] == 'S') S = getNSSummary(FD, FName); } while (0); FuncSummaries[FD] = S; return S; } RetainSummary* RetainSummaryManager::getNSSummary(FunctionDecl* FD, const char* FName) { FName += 2; if (strcmp(FName, "MakeCollectable") == 0) return getUnarySummary(FD, cfmakecollectable); return 0; } static bool isRetain(FunctionDecl* FD, const char* FName) { const char* loc = strstr(FName, "Retain"); return loc && loc[sizeof("Retain")-1] == '\0'; } static bool isRelease(FunctionDecl* FD, const char* FName) { const char* loc = strstr(FName, "Release"); return loc && loc[sizeof("Release")-1] == '\0'; } RetainSummary* RetainSummaryManager::getCFSummary(FunctionDecl* FD, const char* FName) { if (FName[0] == 'C' && FName[1] == 'F') FName += 2; if (isRetain(FD, FName)) return getUnarySummary(FD, cfretain); if (isRelease(FD, FName)) return getUnarySummary(FD, cfrelease); if (strcmp(FName, "MakeCollectable") == 0) return getUnarySummary(FD, cfmakecollectable); return getCFCreateGetRuleSummary(FD, FName); } RetainSummary* RetainSummaryManager::getCGSummary(FunctionDecl* FD, const char* FName) { if (FName[0] == 'C' && FName[1] == 'G') FName += 2; if (isRelease(FD, FName)) return getUnarySummary(FD, cfrelease); if (isRetain(FD, FName)) return getUnarySummary(FD, cfretain); return getCFCreateGetRuleSummary(FD, FName); } RetainSummary* RetainSummaryManager::getCFCreateGetRuleSummary(FunctionDecl* FD, const char* FName) { if (strstr(FName, "Create") || strstr(FName, "Copy")) return getCFSummaryCreateRule(FD); if (strstr(FName, "Get")) return getCFSummaryGetRule(FD); return 0; } RetainSummary* RetainSummaryManager::getUnarySummary(FunctionDecl* FD, UnaryFuncKind func) { FunctionTypeProto* FT = dyn_cast(FD->getType().getTypePtr()); if (FT) { if (FT->getNumArgs() != 1) return 0; TypedefType* ArgT = dyn_cast(FT->getArgType(0).getTypePtr()); if (!ArgT) return 0; if (!ArgT->isPointerType()) return NULL; } assert (ScratchArgs.empty()); switch (func) { case cfretain: { ScratchArgs.push_back(std::make_pair(0, IncRef)); return getPersistentSummary(RetEffect::MakeAlias(0), DoNothing, DoNothing); } case cfrelease: { ScratchArgs.push_back(std::make_pair(0, DecRef)); return getPersistentSummary(RetEffect::MakeNoRet(), DoNothing, DoNothing); } case cfmakecollectable: { if (GCEnabled) ScratchArgs.push_back(std::make_pair(0, DecRef)); return getPersistentSummary(RetEffect::MakeAlias(0), DoNothing, DoNothing); } default: assert (false && "Not a supported unary function."); return 0; } } RetainSummary* RetainSummaryManager::getCFSummaryCreateRule(FunctionDecl* FD) { FunctionType* FT = dyn_cast(FD->getType().getTypePtr()); if (FT && !isCFRefType(FT->getResultType())) return getPersistentSummary(RetEffect::MakeNoRet()); assert (ScratchArgs.empty()); if (FD->getIdentifier() == CFDictionaryCreateII) { ScratchArgs.push_back(std::make_pair(1, DoNothingByRef)); ScratchArgs.push_back(std::make_pair(2, DoNothingByRef)); } return getPersistentSummary(RetEffect::MakeOwned(true)); } RetainSummary* RetainSummaryManager::getCFSummaryGetRule(FunctionDecl* FD) { FunctionType* FT = dyn_cast(FD->getType().getTypePtr()); if (FT) { QualType RetTy = FT->getResultType(); // FIXME: For now we assume that all pointer types returned are referenced // counted. Since this is the "Get" rule, we assume non-ownership, which // works fine for things that are not reference counted. We do this because // some generic data structures return "void*". We need something better // in the future. if (!isCFRefType(RetTy) && !RetTy->isPointerType()) return getPersistentSummary(RetEffect::MakeNoRet(), DoNothing, DoNothing); } // FIXME: Add special-cases for functions that retain/release. For now // just handle the default case. assert (ScratchArgs.empty()); return getPersistentSummary(RetEffect::MakeNotOwned(), DoNothing, DoNothing); } //===----------------------------------------------------------------------===// // Summary creation for Selectors. //===----------------------------------------------------------------------===// RetainSummary* RetainSummaryManager::getInitMethodSummary(ObjCMessageExpr* ME) { assert(ScratchArgs.empty()); RetainSummary* Summ = getPersistentSummary(RetEffect::MakeReceiverAlias()); ObjCMethodSummaries[ME] = Summ; return Summ; } RetainSummary* RetainSummaryManager::getMethodSummary(ObjCMessageExpr* ME, ObjCInterfaceDecl* ID) { Selector S = ME->getSelector(); // Look up a summary in our summary cache. ObjCMethodSummariesTy::iterator I = ObjCMethodSummaries.find(ID, S); if (I != ObjCMethodSummaries.end()) return I->second; if (!ME->getType()->isPointerType()) return 0; // "initXXX": pass-through for receiver. const char* s = S.getIdentifierInfoForSlot(0)->getName(); assert (ScratchArgs.empty()); if (strncmp(s, "init", 4) == 0 || strncmp(s, "_init", 5) == 0) return getInitMethodSummary(ME); // "copyXXX", "createXXX", "newXXX": allocators. if (!isNSType(ME->getReceiver()->getType())) return 0; if (CStrInCStrNoCase(s, "create") || CStrInCStrNoCase(s, "copy") || CStrInCStrNoCase(s, "new")) { RetEffect E = isGCEnabled() ? RetEffect::MakeNoRet() : RetEffect::MakeOwned(true); RetainSummary* Summ = getPersistentSummary(E); ObjCMethodSummaries[ME] = Summ; return Summ; } return 0; } RetainSummary* RetainSummaryManager::getClassMethodSummary(IdentifierInfo* ClsName, Selector S) { // FIXME: Eventually we should properly do class method summaries, but // it requires us being able to walk the type hierarchy. Unfortunately, // we cannot do this with just an IdentifierInfo* for the class name. // Look up a summary in our cache of Selectors -> Summaries. ObjCMethodSummariesTy::iterator I = ObjCClassMethodSummaries.find(ClsName, S); if (I != ObjCClassMethodSummaries.end()) return I->second; return 0; } void RetainSummaryManager::InitializeClassMethodSummaries() { assert (ScratchArgs.empty()); RetEffect E = isGCEnabled() ? RetEffect::MakeNoRet() : RetEffect::MakeOwned(true); RetainSummary* Summ = getPersistentSummary(E); // Create the summaries for "alloc", "new", and "allocWithZone:" for // NSObject and its derivatives. addNSObjectClsMethSummary(GetNullarySelector("alloc", Ctx), Summ); addNSObjectClsMethSummary(GetNullarySelector("new", Ctx), Summ); addNSObjectClsMethSummary(GetUnarySelector("allocWithZone", Ctx), Summ); // Create the [NSAssertionHandler currentHander] summary. addClsMethSummary(&Ctx.Idents.get("NSAssertionHandler"), GetNullarySelector("currentHandler", Ctx), getPersistentSummary(RetEffect::MakeNotOwned())); } void RetainSummaryManager::InitializeMethodSummaries() { assert (ScratchArgs.empty()); // Create the "init" selector. It just acts as a pass-through for the // receiver. RetainSummary* InitSumm = getPersistentSummary(RetEffect::MakeReceiverAlias()); addNSObjectMethSummary(GetNullarySelector("init", Ctx), InitSumm); // The next methods are allocators. RetEffect E = isGCEnabled() ? RetEffect::MakeNoRet() : RetEffect::MakeOwned(true); RetainSummary* Summ = getPersistentSummary(E); // Create the "copy" selector. addNSObjectMethSummary(GetNullarySelector("copy", Ctx), Summ); // Create the "mutableCopy" selector. addNSObjectMethSummary(GetNullarySelector("mutableCopy", Ctx), Summ); // Create the "retain" selector. E = RetEffect::MakeReceiverAlias(); Summ = getPersistentSummary(E, isGCEnabled() ? DoNothing : IncRef); addNSObjectMethSummary(GetNullarySelector("retain", Ctx), Summ); // Create the "release" selector. Summ = getPersistentSummary(E, isGCEnabled() ? DoNothing : DecRef); addNSObjectMethSummary(GetNullarySelector("release", Ctx), Summ); // Create the "drain" selector. Summ = getPersistentSummary(E, isGCEnabled() ? DoNothing : DecRef); addNSObjectMethSummary(GetNullarySelector("drain", Ctx), Summ); // Create the "autorelease" selector. Summ = getPersistentSummary(E, isGCEnabled() ? DoNothing : Autorelease); addNSObjectMethSummary(GetNullarySelector("autorelease", Ctx), Summ); // For NSWindow, allocated objects are (initially) self-owned. RetainSummary *NSWindowSumm = getPersistentSummary(RetEffect::MakeReceiverAlias(), SelfOwn); addInstMethSummary("NSWindow", NSWindowSumm, "initWithContentRect", "styleMask", "backing", "defer", NULL); addInstMethSummary("NSWindow", NSWindowSumm, "initWithContentRect", "styleMask", "backing", "defer", "screen", NULL); // For NSPanel (which subclasses NSWindow), allocated objects are not // self-owned. addInstMethSummary("NSPanel", InitSumm, "initWithContentRect", "styleMask", "backing", "defer", NULL); addInstMethSummary("NSPanel", InitSumm, "initWithContentRect", "styleMask", "backing", "defer", "screen", NULL); // Create NSAssertionHandler summaries. addPanicSummary("NSAssertionHandler", "handleFailureInFunction", "file", "lineNumber", "description", NULL); addPanicSummary("NSAssertionHandler", "handleFailureInMethod", "object", "file", "lineNumber", "description", NULL); } //===----------------------------------------------------------------------===// // Reference-counting logic (typestate + counts). //===----------------------------------------------------------------------===// namespace { class VISIBILITY_HIDDEN RefVal { public: enum Kind { Owned = 0, // Owning reference. NotOwned, // Reference is not owned by still valid (not freed). Released, // Object has been released. ReturnedOwned, // Returned object passes ownership to caller. ReturnedNotOwned, // Return object does not pass ownership to caller. ErrorUseAfterRelease, // Object used after released. ErrorReleaseNotOwned, // Release of an object that was not owned. ErrorLeak // A memory leak due to excessive reference counts. }; private: Kind kind; unsigned Cnt; QualType T; RefVal(Kind k, unsigned cnt, QualType t) : kind(k), Cnt(cnt), T(t) {} RefVal(Kind k, unsigned cnt = 0) : kind(k), Cnt(cnt) {} public: Kind getKind() const { return kind; } unsigned getCount() const { return Cnt; } QualType getType() const { return T; } // Useful predicates. static bool isError(Kind k) { return k >= ErrorUseAfterRelease; } static bool isLeak(Kind k) { return k == ErrorLeak; } bool isOwned() const { return getKind() == Owned; } bool isNotOwned() const { return getKind() == NotOwned; } bool isReturnedOwned() const { return getKind() == ReturnedOwned; } bool isReturnedNotOwned() const { return getKind() == ReturnedNotOwned; } bool isNonLeakError() const { Kind k = getKind(); return isError(k) && !isLeak(k); } // State creation: normal state. static RefVal makeOwned(QualType t, unsigned Count = 1) { return RefVal(Owned, Count, t); } static RefVal makeNotOwned(QualType t, unsigned Count = 0) { return RefVal(NotOwned, Count, t); } static RefVal makeReturnedOwned(unsigned Count) { return RefVal(ReturnedOwned, Count); } static RefVal makeReturnedNotOwned() { return RefVal(ReturnedNotOwned); } // Comparison, profiling, and pretty-printing. bool operator==(const RefVal& X) const { return kind == X.kind && Cnt == X.Cnt && T == X.T; } RefVal operator-(size_t i) const { return RefVal(getKind(), getCount() - i, getType()); } RefVal operator+(size_t i) const { return RefVal(getKind(), getCount() + i, getType()); } RefVal operator^(Kind k) const { return RefVal(k, getCount(), getType()); } void Profile(llvm::FoldingSetNodeID& ID) const { ID.AddInteger((unsigned) kind); ID.AddInteger(Cnt); ID.Add(T); } void print(std::ostream& Out) const; }; void RefVal::print(std::ostream& Out) const { if (!T.isNull()) Out << "Tracked Type:" << T.getAsString() << '\n'; switch (getKind()) { default: assert(false); case Owned: { Out << "Owned"; unsigned cnt = getCount(); if (cnt) Out << " (+ " << cnt << ")"; break; } case NotOwned: { Out << "NotOwned"; unsigned cnt = getCount(); if (cnt) Out << " (+ " << cnt << ")"; break; } case ReturnedOwned: { Out << "ReturnedOwned"; unsigned cnt = getCount(); if (cnt) Out << " (+ " << cnt << ")"; break; } case ReturnedNotOwned: { Out << "ReturnedNotOwned"; unsigned cnt = getCount(); if (cnt) Out << " (+ " << cnt << ")"; break; } case Released: Out << "Released"; break; case ErrorLeak: Out << "Leaked"; break; case ErrorUseAfterRelease: Out << "Use-After-Release [ERROR]"; break; case ErrorReleaseNotOwned: Out << "Release of Not-Owned [ERROR]"; break; } } } // end anonymous namespace //===----------------------------------------------------------------------===// // RefBindings - State used to track object reference counts. //===----------------------------------------------------------------------===// typedef llvm::ImmutableMap RefBindings; static int RefBIndex = 0; namespace clang { template<> struct GRStateTrait : public GRStatePartialTrait { static inline void* GDMIndex() { return &RefBIndex; } }; } //===----------------------------------------------------------------------===// // Transfer functions. //===----------------------------------------------------------------------===// namespace { class VISIBILITY_HIDDEN CFRefCount : public GRSimpleVals { public: // Type definitions. typedef llvm::DenseMap > ReleasesNotOwnedTy; typedef ReleasesNotOwnedTy UseAfterReleasesTy; typedef llvm::DenseMap*> LeaksTy; class BindingsPrinter : public GRState::Printer { public: virtual void Print(std::ostream& Out, const GRState* state, const char* nl, const char* sep); }; private: RetainSummaryManager Summaries; const LangOptions& LOpts; UseAfterReleasesTy UseAfterReleases; ReleasesNotOwnedTy ReleasesNotOwned; LeaksTy Leaks; RefBindings Update(RefBindings B, SymbolID sym, RefVal V, ArgEffect E, RefVal::Kind& hasErr, RefBindings::Factory& RefBFactory); RefVal::Kind& Update(GRStateRef& state, SymbolID sym, RefVal V, ArgEffect E, RefVal::Kind& hasErr) { state = state.set(Update(state.get(), sym, V, E, hasErr, state.get_context())); return hasErr; } void ProcessNonLeakError(ExplodedNodeSet& Dst, GRStmtNodeBuilder& Builder, Expr* NodeExpr, Expr* ErrorExpr, ExplodedNode* Pred, const GRState* St, RefVal::Kind hasErr, SymbolID Sym); const GRState* HandleSymbolDeath(GRStateManager& VMgr, const GRState* St, SymbolID sid, RefVal V, bool& hasLeak); public: CFRefCount(ASTContext& Ctx, bool gcenabled, const LangOptions& lopts) : Summaries(Ctx, gcenabled), LOpts(lopts) {} virtual ~CFRefCount() { for (LeaksTy::iterator I = Leaks.begin(), E = Leaks.end(); I!=E; ++I) delete I->second; } virtual void RegisterChecks(GRExprEngine& Eng); virtual void RegisterPrinters(std::vector& Printers) { Printers.push_back(new BindingsPrinter()); } bool isGCEnabled() const { return Summaries.isGCEnabled(); } const LangOptions& getLangOptions() const { return LOpts; } // Calls. void EvalSummary(ExplodedNodeSet& Dst, GRExprEngine& Eng, GRStmtNodeBuilder& Builder, Expr* Ex, Expr* Receiver, RetainSummary* Summ, ExprIterator arg_beg, ExprIterator arg_end, ExplodedNode* Pred); virtual void EvalCall(ExplodedNodeSet& Dst, GRExprEngine& Eng, GRStmtNodeBuilder& Builder, CallExpr* CE, SVal L, ExplodedNode* Pred); virtual void EvalObjCMessageExpr(ExplodedNodeSet& Dst, GRExprEngine& Engine, GRStmtNodeBuilder& Builder, ObjCMessageExpr* ME, ExplodedNode* Pred); bool EvalObjCMessageExprAux(ExplodedNodeSet& Dst, GRExprEngine& Engine, GRStmtNodeBuilder& Builder, ObjCMessageExpr* ME, ExplodedNode* Pred); // Stores. virtual void EvalStore(ExplodedNodeSet& Dst, GRExprEngine& Engine, GRStmtNodeBuilder& Builder, Expr* E, ExplodedNode* Pred, const GRState* St, SVal TargetLV, SVal Val); // End-of-path. virtual void EvalEndPath(GRExprEngine& Engine, GREndPathNodeBuilder& Builder); virtual void EvalDeadSymbols(ExplodedNodeSet& Dst, GRExprEngine& Engine, GRStmtNodeBuilder& Builder, ExplodedNode* Pred, Stmt* S, const GRState* St, const GRStateManager::DeadSymbolsTy& Dead); // Return statements. virtual void EvalReturn(ExplodedNodeSet& Dst, GRExprEngine& Engine, GRStmtNodeBuilder& Builder, ReturnStmt* S, ExplodedNode* Pred); // Assumptions. virtual const GRState* EvalAssume(GRStateManager& VMgr, const GRState* St, SVal Cond, bool Assumption, bool& isFeasible); // Error iterators. typedef UseAfterReleasesTy::iterator use_after_iterator; typedef ReleasesNotOwnedTy::iterator bad_release_iterator; typedef LeaksTy::iterator leaks_iterator; use_after_iterator use_after_begin() { return UseAfterReleases.begin(); } use_after_iterator use_after_end() { return UseAfterReleases.end(); } bad_release_iterator bad_release_begin() { return ReleasesNotOwned.begin(); } bad_release_iterator bad_release_end() { return ReleasesNotOwned.end(); } leaks_iterator leaks_begin() { return Leaks.begin(); } leaks_iterator leaks_end() { return Leaks.end(); } }; } // end anonymous namespace void CFRefCount::BindingsPrinter::Print(std::ostream& Out, const GRState* state, const char* nl, const char* sep) { RefBindings B = state->get(); if (!B.isEmpty()) Out << sep << nl; for (RefBindings::iterator I=B.begin(), E=B.end(); I!=E; ++I) { Out << (*I).first << " : "; (*I).second.print(Out); Out << nl; } } static inline ArgEffect GetArgE(RetainSummary* Summ, unsigned idx) { return Summ ? Summ->getArg(idx) : MayEscape; } static inline RetEffect GetRetEffect(RetainSummary* Summ) { return Summ ? Summ->getRetEffect() : RetEffect::MakeNoRet(); } static inline ArgEffect GetReceiverE(RetainSummary* Summ) { return Summ ? Summ->getReceiverEffect() : DoNothing; } static inline bool IsEndPath(RetainSummary* Summ) { return Summ ? Summ->isEndPath() : false; } void CFRefCount::ProcessNonLeakError(ExplodedNodeSet& Dst, GRStmtNodeBuilder& Builder, Expr* NodeExpr, Expr* ErrorExpr, ExplodedNode* Pred, const GRState* St, RefVal::Kind hasErr, SymbolID Sym) { Builder.BuildSinks = true; GRExprEngine::NodeTy* N = Builder.MakeNode(Dst, NodeExpr, Pred, St); if (!N) return; switch (hasErr) { default: assert(false); case RefVal::ErrorUseAfterRelease: UseAfterReleases[N] = std::make_pair(ErrorExpr, Sym); break; case RefVal::ErrorReleaseNotOwned: ReleasesNotOwned[N] = std::make_pair(ErrorExpr, Sym); break; } } /// GetReturnType - Used to get the return type of a message expression or /// function call with the intention of affixing that type to a tracked symbol. /// While the the return type can be queried directly from RetEx, when /// invoking class methods we augment to the return type to be that of /// a pointer to the class (as opposed it just being id). static QualType GetReturnType(Expr* RetE, ASTContext& Ctx) { QualType RetTy = RetE->getType(); // FIXME: We aren't handling id<...>. const PointerType* PT = RetTy->getAsPointerType(); if (!PT) return RetTy; // If RetEx is not a message expression just return its type. // If RetEx is a message expression, return its types if it is something /// more specific than id. ObjCMessageExpr* ME = dyn_cast(RetE); if (!ME || !Ctx.isObjCIdType(PT->getPointeeType())) return RetTy; ObjCInterfaceDecl* D = ME->getClassInfo().first; // At this point we know the return type of the message expression is id. // If we have an ObjCInterceDecl, we know this is a call to a class method // whose type we can resolve. In such cases, promote the return type to // Class*. return !D ? RetTy : Ctx.getPointerType(Ctx.getObjCInterfaceType(D)); } void CFRefCount::EvalSummary(ExplodedNodeSet& Dst, GRExprEngine& Eng, GRStmtNodeBuilder& Builder, Expr* Ex, Expr* Receiver, RetainSummary* Summ, ExprIterator arg_beg, ExprIterator arg_end, ExplodedNode* Pred) { // Get the state. GRStateRef state(Builder.GetState(Pred), Eng.getStateManager()); // Evaluate the effect of the arguments. RefVal::Kind hasErr = (RefVal::Kind) 0; unsigned idx = 0; Expr* ErrorExpr = NULL; SymbolID ErrorSym = 0; for (ExprIterator I = arg_beg; I != arg_end; ++I, ++idx) { SVal V = state.GetSVal(*I); if (isa(V)) { SymbolID Sym = cast(V).getSymbol(); if (RefBindings::data_type* T = state.get(Sym)) if (Update(state, Sym, *T, GetArgE(Summ, idx), hasErr)) { ErrorExpr = *I; ErrorSym = Sym; break; } } else if (isa(V)) { #if 0 // Nuke all arguments passed by reference. StateMgr.Unbind(StVals, cast(V)); #else if (loc::MemRegionVal* MR = dyn_cast(&V)) { if (GetArgE(Summ, idx) == DoNothingByRef) continue; // Invalidate the value of the variable passed by reference. // FIXME: Either this logic should also be replicated in GRSimpleVals // or should be pulled into a separate "constraint engine." // FIXME: We can have collisions on the conjured symbol if the // expression *I also creates conjured symbols. We probably want // to identify conjured symbols by an expression pair: the enclosing // expression (the context) and the expression itself. This should // disambiguate conjured symbols. // Is the invalidated variable something that we were tracking? SVal X = state.GetSVal(*MR); if (isa(X)) { SymbolID Sym = cast(X).getSymbol(); state = state.remove(Sym); } const TypedRegion* R = dyn_cast(MR->getRegion()); if (R) { // Set the value of the variable to be a conjured symbol. unsigned Count = Builder.getCurrentBlockCount(); QualType T = R->getType(); // FIXME: handle structs. if (T->isIntegerType() || Loc::IsLocType(T)) { SymbolID NewSym = Eng.getSymbolManager().getConjuredSymbol(*I, T, Count); state = state.SetSVal(*MR, Loc::IsLocType(T) ? cast(loc::SymbolVal(NewSym)) : cast(nonloc::SymbolVal(NewSym))); } else { state = state.SetSVal(*MR, UnknownVal()); } } else state = state.SetSVal(*MR, UnknownVal()); } else { // Nuke all other arguments passed by reference. state = state.Unbind(cast(V)); } #endif } else if (isa(V)) state = state.Unbind(cast(V).getLoc()); } // Evaluate the effect on the message receiver. if (!ErrorExpr && Receiver) { SVal V = state.GetSVal(Receiver); if (isa(V)) { SymbolID Sym = cast(V).getSymbol(); if (const RefVal* T = state.get(Sym)) if (Update(state, Sym, *T, GetReceiverE(Summ), hasErr)) { ErrorExpr = Receiver; ErrorSym = Sym; } } } // Process any errors. if (hasErr) { ProcessNonLeakError(Dst, Builder, Ex, ErrorExpr, Pred, state, hasErr, ErrorSym); return; } // Consult the summary for the return value. RetEffect RE = GetRetEffect(Summ); switch (RE.getKind()) { default: assert (false && "Unhandled RetEffect."); break; case RetEffect::NoRet: { // Make up a symbol for the return value (not reference counted). // FIXME: This is basically copy-and-paste from GRSimpleVals. We // should compose behavior, not copy it. // FIXME: We eventually should handle structs and other compound types // that are returned by value. QualType T = Ex->getType(); if (T->isIntegerType() || Loc::IsLocType(T)) { unsigned Count = Builder.getCurrentBlockCount(); SymbolID Sym = Eng.getSymbolManager().getConjuredSymbol(Ex, Count); SVal X = Loc::IsLocType(Ex->getType()) ? cast(loc::SymbolVal(Sym)) : cast(nonloc::SymbolVal(Sym)); state = state.SetSVal(Ex, X, false); } break; } case RetEffect::Alias: { unsigned idx = RE.getIndex(); assert (arg_end >= arg_beg); assert (idx < (unsigned) (arg_end - arg_beg)); SVal V = state.GetSVal(*(arg_beg+idx)); state = state.SetSVal(Ex, V, false); break; } case RetEffect::ReceiverAlias: { assert (Receiver); SVal V = state.GetSVal(Receiver); state = state.SetSVal(Ex, V, false); break; } case RetEffect::OwnedAllocatedSymbol: case RetEffect::OwnedSymbol: { unsigned Count = Builder.getCurrentBlockCount(); SymbolID Sym = Eng.getSymbolManager().getConjuredSymbol(Ex, Count); QualType RetT = GetReturnType(Ex, Eng.getContext()); state = state.set(Sym, RefVal::makeOwned(RetT)); state = state.SetSVal(Ex, loc::SymbolVal(Sym), false); #if 0 RefBindings B = GetRefBindings(StImpl); SetRefBindings(StImpl, RefBFactory.Add(B, Sym, RefVal::makeOwned(RetT))); #endif // FIXME: Add a flag to the checker where allocations are allowed to fail. if (RE.getKind() == RetEffect::OwnedAllocatedSymbol) state = state.AddNE(Sym, Eng.getBasicVals().getZeroWithPtrWidth()); break; } case RetEffect::NotOwnedSymbol: { unsigned Count = Builder.getCurrentBlockCount(); SymbolID Sym = Eng.getSymbolManager().getConjuredSymbol(Ex, Count); QualType RetT = GetReturnType(Ex, Eng.getContext()); state = state.set(Sym, RefVal::makeNotOwned(RetT)); state = state.SetSVal(Ex, loc::SymbolVal(Sym), false); break; } } // Is this a sink? if (IsEndPath(Summ)) Builder.MakeSinkNode(Dst, Ex, Pred, state); else Builder.MakeNode(Dst, Ex, Pred, state); } void CFRefCount::EvalCall(ExplodedNodeSet& Dst, GRExprEngine& Eng, GRStmtNodeBuilder& Builder, CallExpr* CE, SVal L, ExplodedNode* Pred) { RetainSummary* Summ = !isa(L) ? 0 : Summaries.getSummary(cast(L).getDecl()); EvalSummary(Dst, Eng, Builder, CE, 0, Summ, CE->arg_begin(), CE->arg_end(), Pred); } void CFRefCount::EvalObjCMessageExpr(ExplodedNodeSet& Dst, GRExprEngine& Eng, GRStmtNodeBuilder& Builder, ObjCMessageExpr* ME, ExplodedNode* Pred) { RetainSummary* Summ; if (Expr* Receiver = ME->getReceiver()) { // We need the type-information of the tracked receiver object // Retrieve it from the state. ObjCInterfaceDecl* ID = 0; // FIXME: Wouldn't it be great if this code could be reduced? It's just // a chain of lookups. const GRState* St = Builder.GetState(Pred); SVal V = Eng.getStateManager().GetSVal(St, Receiver ); if (isa(V)) { SymbolID Sym = cast(V).getSymbol(); if (const RefVal* T = St->get(Sym)) { QualType Ty = T->getType(); if (const PointerType* PT = Ty->getAsPointerType()) { QualType PointeeTy = PT->getPointeeType(); if (ObjCInterfaceType* IT = dyn_cast(PointeeTy)) ID = IT->getDecl(); } } } Summ = Summaries.getMethodSummary(ME, ID); } else Summ = Summaries.getClassMethodSummary(ME->getClassName(), ME->getSelector()); EvalSummary(Dst, Eng, Builder, ME, ME->getReceiver(), Summ, ME->arg_begin(), ME->arg_end(), Pred); } // Stores. void CFRefCount::EvalStore(ExplodedNodeSet& Dst, GRExprEngine& Eng, GRStmtNodeBuilder& Builder, Expr* E, ExplodedNode* Pred, const GRState* St, SVal TargetLV, SVal Val) { // Check if we have a binding for "Val" and if we are storing it to something // we don't understand or otherwise the value "escapes" the function. if (!isa(Val)) return; // Are we storing to something that causes the value to "escape"? bool escapes = false; // A value escapes in three possible cases (this may change): // // (1) we are binding to something that is not a memory region. // (2) we are binding to a memregion that does not have stack storage // (3) we are binding to a memregion with stack storage that the store // does not understand. SymbolID Sym = cast(Val).getSymbol(); GRStateRef state(St, Eng.getStateManager()); if (!isa(TargetLV)) escapes = true; else { const MemRegion* R = cast(TargetLV).getRegion(); escapes = !Eng.getStateManager().hasStackStorage(R); if (!escapes) { // To test (3), generate a new state with the binding removed. If it is // the same state, then it escapes (since the store cannot represent // the binding). GRStateRef stateNew = state.SetSVal(cast(TargetLV), Val); escapes = (stateNew == state); } } if (!escapes) return; // Do we have a reference count binding? // FIXME: Is this step even needed? We do blow away the binding anyway. if (!state.get(Sym)) return; // Nuke the binding. state = state.remove(Sym); // Hand of the remaining logic to the parent implementation. GRSimpleVals::EvalStore(Dst, Eng, Builder, E, Pred, state, TargetLV, Val); } // End-of-path. const GRState* CFRefCount::HandleSymbolDeath(GRStateManager& VMgr, const GRState* St, SymbolID sid, RefVal V, bool& hasLeak) { hasLeak = V.isOwned() || ((V.isNotOwned() || V.isReturnedOwned()) && V.getCount() > 0); GRStateRef state(St, VMgr); if (!hasLeak) return state.remove(sid); return state.set(sid, V ^ RefVal::ErrorLeak); } void CFRefCount::EvalEndPath(GRExprEngine& Eng, GREndPathNodeBuilder& Builder) { const GRState* St = Builder.getState(); RefBindings B = St->get(); llvm::SmallVector Leaked; for (RefBindings::iterator I = B.begin(), E = B.end(); I != E; ++I) { bool hasLeak = false; St = HandleSymbolDeath(Eng.getStateManager(), St, (*I).first, (*I).second, hasLeak); if (hasLeak) Leaked.push_back((*I).first); } if (Leaked.empty()) return; ExplodedNode* N = Builder.MakeNode(St); if (!N) return; std::vector*& LeaksAtNode = Leaks[N]; assert (!LeaksAtNode); LeaksAtNode = new std::vector(); for (llvm::SmallVector::iterator I=Leaked.begin(), E = Leaked.end(); I != E; ++I) (*LeaksAtNode).push_back(*I); } // Dead symbols. void CFRefCount::EvalDeadSymbols(ExplodedNodeSet& Dst, GRExprEngine& Eng, GRStmtNodeBuilder& Builder, ExplodedNode* Pred, Stmt* S, const GRState* St, const GRStateManager::DeadSymbolsTy& Dead) { // FIXME: a lot of copy-and-paste from EvalEndPath. Refactor. RefBindings B = St->get(); llvm::SmallVector Leaked; for (GRStateManager::DeadSymbolsTy::const_iterator I=Dead.begin(), E=Dead.end(); I!=E; ++I) { const RefVal* T = B.lookup(*I); if (!T) continue; bool hasLeak = false; St = HandleSymbolDeath(Eng.getStateManager(), St, *I, *T, hasLeak); if (hasLeak) Leaked.push_back(*I); } if (Leaked.empty()) return; ExplodedNode* N = Builder.MakeNode(Dst, S, Pred, St); if (!N) return; std::vector*& LeaksAtNode = Leaks[N]; assert (!LeaksAtNode); LeaksAtNode = new std::vector(); for (llvm::SmallVector::iterator I=Leaked.begin(), E = Leaked.end(); I != E; ++I) (*LeaksAtNode).push_back(*I); } // Return statements. void CFRefCount::EvalReturn(ExplodedNodeSet& Dst, GRExprEngine& Eng, GRStmtNodeBuilder& Builder, ReturnStmt* S, ExplodedNode* Pred) { Expr* RetE = S->getRetValue(); if (!RetE) return; GRStateRef state(Builder.GetState(Pred), Eng.getStateManager()); SVal V = state.GetSVal(RetE); if (!isa(V)) return; // Get the reference count binding (if any). SymbolID Sym = cast(V).getSymbol(); const RefVal* T = state.get(Sym); if (!T) return; // Change the reference count. RefVal X = *T; switch (X.getKind()) { case RefVal::Owned: { unsigned cnt = X.getCount(); assert (cnt > 0); X = RefVal::makeReturnedOwned(cnt - 1); break; } case RefVal::NotOwned: { unsigned cnt = X.getCount(); X = cnt ? RefVal::makeReturnedOwned(cnt - 1) : RefVal::makeReturnedNotOwned(); break; } default: return; } // Update the binding. state = state.set(Sym, X); Builder.MakeNode(Dst, S, Pred, state); } // Assumptions. const GRState* CFRefCount::EvalAssume(GRStateManager& VMgr, const GRState* St, SVal Cond, bool Assumption, bool& isFeasible) { // FIXME: We may add to the interface of EvalAssume the list of symbols // whose assumptions have changed. For now we just iterate through the // bindings and check if any of the tracked symbols are NULL. This isn't // too bad since the number of symbols we will track in practice are // probably small and EvalAssume is only called at branches and a few // other places. RefBindings B = St->get(); if (B.isEmpty()) return St; bool changed = false; GRStateRef state(St, VMgr); RefBindings::Factory& RefBFactory = state.get_context(); for (RefBindings::iterator I=B.begin(), E=B.end(); I!=E; ++I) { // Check if the symbol is null (or equal to any constant). // If this is the case, stop tracking the symbol. if (VMgr.getSymVal(St, I.getKey())) { changed = true; B = RefBFactory.Remove(B, I.getKey()); } } if (changed) state = state.set(B); return state; } RefBindings CFRefCount::Update(RefBindings B, SymbolID sym, RefVal V, ArgEffect E, RefVal::Kind& hasErr, RefBindings::Factory& RefBFactory) { // FIXME: This dispatch can potentially be sped up by unifiying it into // a single switch statement. Opt for simplicity for now. switch (E) { default: assert (false && "Unhandled CFRef transition."); case MayEscape: if (V.getKind() == RefVal::Owned) { V = V ^ RefVal::NotOwned; break; } // Fall-through. case DoNothingByRef: case DoNothing: if (!isGCEnabled() && V.getKind() == RefVal::Released) { V = V ^ RefVal::ErrorUseAfterRelease; hasErr = V.getKind(); break; } return B; case Autorelease: case StopTracking: return RefBFactory.Remove(B, sym); case IncRef: switch (V.getKind()) { default: assert(false); case RefVal::Owned: case RefVal::NotOwned: V = V + 1; break; case RefVal::Released: if (isGCEnabled()) V = V ^ RefVal::Owned; else { V = V ^ RefVal::ErrorUseAfterRelease; hasErr = V.getKind(); } break; } break; case SelfOwn: V = V ^ RefVal::NotOwned; // Fall-through. case DecRef: switch (V.getKind()) { default: assert (false); case RefVal::Owned: V = V.getCount() > 1 ? V - 1 : V ^ RefVal::Released; break; case RefVal::NotOwned: if (V.getCount() > 0) V = V - 1; else { V = V ^ RefVal::ErrorReleaseNotOwned; hasErr = V.getKind(); } break; case RefVal::Released: V = V ^ RefVal::ErrorUseAfterRelease; hasErr = V.getKind(); break; } break; } return RefBFactory.Add(B, sym, V); } //===----------------------------------------------------------------------===// // Error reporting. //===----------------------------------------------------------------------===// namespace { //===-------------===// // Bug Descriptions. // //===-------------===// class VISIBILITY_HIDDEN CFRefBug : public BugTypeCacheLocation { protected: CFRefCount& TF; public: CFRefBug(CFRefCount& tf) : TF(tf) {} CFRefCount& getTF() { return TF; } const CFRefCount& getTF() const { return TF; } virtual bool isLeak() const { return false; } const char* getCategory() const { return "Memory (Core Foundation/Objective-C)"; } }; class VISIBILITY_HIDDEN UseAfterRelease : public CFRefBug { public: UseAfterRelease(CFRefCount& tf) : CFRefBug(tf) {} virtual const char* getName() const { return "use-after-release"; } virtual const char* getDescription() const { return "Reference-counted object is used after it is released."; } virtual void EmitWarnings(BugReporter& BR); }; class VISIBILITY_HIDDEN BadRelease : public CFRefBug { public: BadRelease(CFRefCount& tf) : CFRefBug(tf) {} virtual const char* getName() const { return "bad release"; } virtual const char* getDescription() const { return "Incorrect decrement of the reference count of a " "CoreFoundation object: " "The object is not owned at this point by the caller."; } virtual void EmitWarnings(BugReporter& BR); }; class VISIBILITY_HIDDEN Leak : public CFRefBug { public: Leak(CFRefCount& tf) : CFRefBug(tf) {} virtual const char* getName() const { if (getTF().isGCEnabled()) return "leak (GC)"; if (getTF().getLangOptions().getGCMode() == LangOptions::HybridGC) return "leak (hybrid MM, non-GC)"; assert (getTF().getLangOptions().getGCMode() == LangOptions::NonGC); return "leak"; } virtual const char* getDescription() const { return "Object leaked"; } virtual void EmitWarnings(BugReporter& BR); virtual void GetErrorNodes(std::vector*>& Nodes); virtual bool isLeak() const { return true; } virtual bool isCached(BugReport& R); }; //===---------===// // Bug Reports. // //===---------===// class VISIBILITY_HIDDEN CFRefReport : public RangedBugReport { SymbolID Sym; public: CFRefReport(CFRefBug& D, ExplodedNode *n, SymbolID sym) : RangedBugReport(D, n), Sym(sym) {} virtual ~CFRefReport() {} CFRefBug& getBugType() { return (CFRefBug&) RangedBugReport::getBugType(); } const CFRefBug& getBugType() const { return (const CFRefBug&) RangedBugReport::getBugType(); } virtual void getRanges(BugReporter& BR, const SourceRange*& beg, const SourceRange*& end) { if (!getBugType().isLeak()) RangedBugReport::getRanges(BR, beg, end); else beg = end = 0; } SymbolID getSymbol() const { return Sym; } virtual PathDiagnosticPiece* getEndPath(BugReporter& BR, ExplodedNode* N); virtual std::pair getExtraDescriptiveText(); virtual PathDiagnosticPiece* VisitNode(ExplodedNode* N, ExplodedNode* PrevN, ExplodedGraph& G, BugReporter& BR); }; } // end anonymous namespace void CFRefCount::RegisterChecks(GRExprEngine& Eng) { Eng.Register(new UseAfterRelease(*this)); Eng.Register(new BadRelease(*this)); Eng.Register(new Leak(*this)); } static const char* Msgs[] = { "Code is compiled in garbage collection only mode" // GC only " (the bug occurs with garbage collection enabled).", "Code is compiled without garbage collection.", // No GC. "Code is compiled for use with and without garbage collection (GC)." " The bug occurs with GC enabled.", // Hybrid, with GC. "Code is compiled for use with and without garbage collection (GC)." " The bug occurs in non-GC mode." // Hyrbird, without GC/ }; std::pair CFRefReport::getExtraDescriptiveText() { CFRefCount& TF = static_cast(getBugType()).getTF(); switch (TF.getLangOptions().getGCMode()) { default: assert(false); case LangOptions::GCOnly: assert (TF.isGCEnabled()); return std::make_pair(&Msgs[0], &Msgs[0]+1); case LangOptions::NonGC: assert (!TF.isGCEnabled()); return std::make_pair(&Msgs[1], &Msgs[1]+1); case LangOptions::HybridGC: if (TF.isGCEnabled()) return std::make_pair(&Msgs[2], &Msgs[2]+1); else return std::make_pair(&Msgs[3], &Msgs[3]+1); } } PathDiagnosticPiece* CFRefReport::VisitNode(ExplodedNode* N, ExplodedNode* PrevN, ExplodedGraph& G, BugReporter& BR) { // Check if the type state has changed. const GRState* PrevSt = PrevN->getState(); const GRState* CurrSt = N->getState(); RefBindings PrevB = PrevSt->get(); RefBindings CurrB = CurrSt->get(); const RefVal* PrevT = PrevB.lookup(Sym); const RefVal* CurrT = CurrB.lookup(Sym); if (!CurrT) return NULL; const char* Msg = NULL; const RefVal& CurrV = *CurrB.lookup(Sym); if (!PrevT) { Stmt* S = cast(N->getLocation()).getStmt(); if (CurrV.isOwned()) { if (isa(S)) Msg = "Function call returns an object with a +1 retain count" " (owning reference)."; else { assert (isa(S)); Msg = "Method returns an object with a +1 retain count" " (owning reference)."; } } else { assert (CurrV.isNotOwned()); if (isa(S)) Msg = "Function call returns an object with a +0 retain count" " (non-owning reference)."; else { assert (isa(S)); Msg = "Method returns an object with a +0 retain count" " (non-owning reference)."; } } FullSourceLoc Pos(S->getLocStart(), BR.getContext().getSourceManager()); PathDiagnosticPiece* P = new PathDiagnosticPiece(Pos, Msg); if (Expr* Exp = dyn_cast(S)) P->addRange(Exp->getSourceRange()); return P; } // Determine if the typestate has changed. RefVal PrevV = *PrevB.lookup(Sym); if (PrevV == CurrV) return NULL; // The typestate has changed. std::ostringstream os; std::string s; switch (CurrV.getKind()) { case RefVal::Owned: case RefVal::NotOwned: if (PrevV.getCount() == CurrV.getCount()) return 0; if (PrevV.getCount() > CurrV.getCount()) os << "Reference count decremented."; else os << "Reference count incremented."; if (unsigned Count = CurrV.getCount()) { os << " Object has +" << Count; if (Count > 1) os << " retain counts."; else os << " retain count."; } s = os.str(); Msg = s.c_str(); break; case RefVal::Released: Msg = "Object released."; break; case RefVal::ReturnedOwned: Msg = "Object returned to caller as owning reference (single retain count" " transferred to caller)."; break; case RefVal::ReturnedNotOwned: Msg = "Object returned to caller with a +0 (non-owning) retain count."; break; default: return NULL; } Stmt* S = cast(N->getLocation()).getStmt(); FullSourceLoc Pos(S->getLocStart(), BR.getContext().getSourceManager()); PathDiagnosticPiece* P = new PathDiagnosticPiece(Pos, Msg); // Add the range by scanning the children of the statement for any bindings // to Sym. GRStateManager& VSM = cast(BR).getStateManager(); for (Stmt::child_iterator I = S->child_begin(), E = S->child_end(); I!=E; ++I) if (Expr* Exp = dyn_cast_or_null(*I)) { SVal X = VSM.GetSVal(CurrSt, Exp); if (loc::SymbolVal* SV = dyn_cast(&X)) if (SV->getSymbol() == Sym) { P->addRange(Exp->getSourceRange()); break; } } return P; } namespace { class VISIBILITY_HIDDEN FindUniqueBinding : public StoreManager::BindingsHandler { SymbolID Sym; MemRegion* Binding; bool First; public: FindUniqueBinding(SymbolID sym) : Sym(sym), Binding(0), First(true) {} bool HandleBinding(StoreManager& SMgr, Store store, MemRegion* R, SVal val) { if (const loc::SymbolVal* SV = dyn_cast(&val)) { if (SV->getSymbol() != Sym) return true; } else if (const nonloc::SymbolVal* SV=dyn_cast(&val)) { if (SV->getSymbol() != Sym) return true; } else return true; if (Binding) { First = false; return false; } else Binding = R; return true; } operator bool() { return First && Binding; } MemRegion* getRegion() { return Binding; } }; } static std::pair*,MemRegion*> GetAllocationSite(GRStateManager* StateMgr, ExplodedNode* N, SymbolID Sym) { // Find both first node that referred to the tracked symbol and the // memory location that value was store to. ExplodedNode* Last = N; MemRegion* FirstBinding = 0; while (N) { const GRState* St = N->getState(); RefBindings B = St->get(); if (!B.lookup(Sym)) break; if (StateMgr) { FindUniqueBinding FB(Sym); StateMgr->iterBindings(St, FB); if (FB) FirstBinding = FB.getRegion(); } Last = N; N = N->pred_empty() ? NULL : *(N->pred_begin()); } return std::make_pair(Last, FirstBinding); } PathDiagnosticPiece* CFRefReport::getEndPath(BugReporter& br, ExplodedNode* EndN) { GRBugReporter& BR = cast(br); // Tell the BugReporter to report cases when the tracked symbol is // assigned to different variables, etc. cast(BR).addNotableSymbol(Sym); if (!getBugType().isLeak()) return RangedBugReport::getEndPath(BR, EndN); // Get the retain count. unsigned long RetCount = EndN->getState()->get(Sym)->getCount(); // We are a leak. Walk up the graph to get to the first node where the // symbol appeared, and also get the first VarDecl that tracked object // is stored to. ExplodedNode* AllocNode = 0; MemRegion* FirstBinding = 0; llvm::tie(AllocNode, FirstBinding) = GetAllocationSite(&BR.getStateManager(), EndN, Sym); // Get the allocate site. assert (AllocNode); Stmt* FirstStmt = cast(AllocNode->getLocation()).getStmt(); SourceManager& SMgr = BR.getContext().getSourceManager(); unsigned AllocLine = SMgr.getLogicalLineNumber(FirstStmt->getLocStart()); // Get the leak site. We may have multiple ExplodedNodes (one with the // leak) that occur on the same line number; if the node with the leak // has any immediate predecessor nodes with the same line number, find // any transitive-successors that have a different statement and use that // line number instead. This avoids emiting a diagnostic like: // // // 'y' is leaked. // int x = foo(y); // // instead we want: // // int x = foo(y); // // 'y' is leaked. Stmt* S = getStmt(BR); // This is the statement where the leak occured. assert (S); unsigned EndLine = SMgr.getLogicalLineNumber(S->getLocStart()); // Look in the *trimmed* graph at the immediate predecessor of EndN. Does // it occur on the same line? PathDiagnosticPiece::DisplayHint Hint = PathDiagnosticPiece::Above; assert (!EndN->pred_empty()); // Not possible to have 0 predecessors. ExplodedNode *Pred = *(EndN->pred_begin()); ProgramPoint PredPos = Pred->getLocation(); if (PostStmt* PredPS = dyn_cast(&PredPos)) { Stmt* SPred = PredPS->getStmt(); // Predecessor at same line? if (SMgr.getLogicalLineNumber(SPred->getLocStart()) != EndLine) { Hint = PathDiagnosticPiece::Below; S = SPred; } } // Generate the diagnostic. FullSourceLoc L( S->getLocStart(), SMgr); std::ostringstream os; os << "Object allocated on line " << AllocLine; if (FirstBinding) os << " and stored into '" << FirstBinding->getString() << '\''; os << " is no longer referenced after this point and has a retain count of +" << RetCount << " (object leaked)."; return new PathDiagnosticPiece(L, os.str(), Hint); } void UseAfterRelease::EmitWarnings(BugReporter& BR) { for (CFRefCount::use_after_iterator I = TF.use_after_begin(), E = TF.use_after_end(); I != E; ++I) { CFRefReport report(*this, I->first, I->second.second); report.addRange(I->second.first->getSourceRange()); BR.EmitWarning(report); } } void BadRelease::EmitWarnings(BugReporter& BR) { for (CFRefCount::bad_release_iterator I = TF.bad_release_begin(), E = TF.bad_release_end(); I != E; ++I) { CFRefReport report(*this, I->first, I->second.second); report.addRange(I->second.first->getSourceRange()); BR.EmitWarning(report); } } void Leak::EmitWarnings(BugReporter& BR) { for (CFRefCount::leaks_iterator I = TF.leaks_begin(), E = TF.leaks_end(); I != E; ++I) { std::vector& SymV = *(I->second); unsigned n = SymV.size(); for (unsigned i = 0; i < n; ++i) { CFRefReport report(*this, I->first, SymV[i]); BR.EmitWarning(report); } } } void Leak::GetErrorNodes(std::vector*>& Nodes) { for (CFRefCount::leaks_iterator I=TF.leaks_begin(), E=TF.leaks_end(); I!=E; ++I) Nodes.push_back(I->first); } bool Leak::isCached(BugReport& R) { // Most bug reports are cached at the location where they occured. // With leaks, we want to unique them by the location where they were // allocated, and only report only a single path. SymbolID Sym = static_cast(R).getSymbol(); ExplodedNode* AllocNode = GetAllocationSite(0, R.getEndNode(), Sym).first; if (!AllocNode) return false; return BugTypeCacheLocation::isCached(AllocNode->getLocation()); } //===----------------------------------------------------------------------===// // Transfer function creation for external clients. //===----------------------------------------------------------------------===// GRTransferFuncs* clang::MakeCFRefCountTF(ASTContext& Ctx, bool GCEnabled, const LangOptions& lopts) { return new CFRefCount(Ctx, GCEnabled, lopts); }