diff options
Diffstat (limited to 'clang/lib/StaticAnalyzer/Checkers/RetainCountChecker')
6 files changed, 4033 insertions, 0 deletions
diff --git a/clang/lib/StaticAnalyzer/Checkers/RetainCountChecker/RetainCountChecker.cpp b/clang/lib/StaticAnalyzer/Checkers/RetainCountChecker/RetainCountChecker.cpp new file mode 100644 index 00000000000..ce235a7f8dd --- /dev/null +++ b/clang/lib/StaticAnalyzer/Checkers/RetainCountChecker/RetainCountChecker.cpp @@ -0,0 +1,1468 @@ +//==-- RetainCountChecker.cpp - Checks for leaks and other issues -*- 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 RetainCountChecker, which implements +// a reference count checker for Core Foundation and Cocoa on (Mac OS X). +// +//===----------------------------------------------------------------------===// + +#include "RetainCountChecker.h" + +using namespace clang; +using namespace ento; +using namespace objc_retain; +using namespace retaincountchecker; +using llvm::StrInStrNoCase; + +REGISTER_MAP_WITH_PROGRAMSTATE(RefBindings, SymbolRef, RefVal) + +namespace clang { +namespace ento { +namespace retaincountchecker { + +const RefVal *getRefBinding(ProgramStateRef State, SymbolRef Sym) { + return State->get<RefBindings>(Sym); +} + +ProgramStateRef setRefBinding(ProgramStateRef State, SymbolRef Sym, + RefVal Val) { + return State->set<RefBindings>(Sym, Val); +} + +ProgramStateRef removeRefBinding(ProgramStateRef State, SymbolRef Sym) { + return State->remove<RefBindings>(Sym); +} + +} // end namespace retaincountchecker +} // end namespace ento +} // end namespace clang + +void RefVal::print(raw_ostream &Out) const { + if (!T.isNull()) + Out << "Tracked " << T.getAsString() << '/'; + + switch (getKind()) { + default: llvm_unreachable("Invalid RefVal kind"); + 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 ErrorDeallocNotOwned: + Out << "-dealloc (not-owned)"; + break; + + case ErrorLeak: + Out << "Leaked"; + break; + + case ErrorLeakReturned: + Out << "Leaked (Bad naming)"; + break; + + case ErrorUseAfterRelease: + Out << "Use-After-Release [ERROR]"; + break; + + case ErrorReleaseNotOwned: + Out << "Release of Not-Owned [ERROR]"; + break; + + case RefVal::ErrorOverAutorelease: + Out << "Over-autoreleased"; + break; + + case RefVal::ErrorReturnedNotOwned: + Out << "Non-owned object returned instead of owned"; + break; + } + + switch (getIvarAccessHistory()) { + case IvarAccessHistory::None: + break; + case IvarAccessHistory::AccessedDirectly: + Out << " [direct ivar access]"; + break; + case IvarAccessHistory::ReleasedAfterDirectAccess: + Out << " [released after direct ivar access]"; + } + + if (ACnt) { + Out << " [autorelease -" << ACnt << ']'; + } +} + +namespace { +class StopTrackingCallback final : public SymbolVisitor { + ProgramStateRef state; +public: + StopTrackingCallback(ProgramStateRef st) : state(std::move(st)) {} + ProgramStateRef getState() const { return state; } + + bool VisitSymbol(SymbolRef sym) override { + state = state->remove<RefBindings>(sym); + return true; + } +}; +} // end anonymous namespace + +//===----------------------------------------------------------------------===// +// Handle statements that may have an effect on refcounts. +//===----------------------------------------------------------------------===// + +void RetainCountChecker::checkPostStmt(const BlockExpr *BE, + CheckerContext &C) const { + + // Scan the BlockDecRefExprs for any object the retain count checker + // may be tracking. + if (!BE->getBlockDecl()->hasCaptures()) + return; + + ProgramStateRef state = C.getState(); + auto *R = cast<BlockDataRegion>(C.getSVal(BE).getAsRegion()); + + BlockDataRegion::referenced_vars_iterator I = R->referenced_vars_begin(), + E = R->referenced_vars_end(); + + if (I == E) + return; + + // FIXME: For now we invalidate the tracking of all symbols passed to blocks + // via captured variables, even though captured variables result in a copy + // and in implicit increment/decrement of a retain count. + SmallVector<const MemRegion*, 10> Regions; + const LocationContext *LC = C.getLocationContext(); + MemRegionManager &MemMgr = C.getSValBuilder().getRegionManager(); + + for ( ; I != E; ++I) { + const VarRegion *VR = I.getCapturedRegion(); + if (VR->getSuperRegion() == R) { + VR = MemMgr.getVarRegion(VR->getDecl(), LC); + } + Regions.push_back(VR); + } + + state = + state->scanReachableSymbols<StopTrackingCallback>(Regions.data(), + Regions.data() + Regions.size()).getState(); + C.addTransition(state); +} + +void RetainCountChecker::checkPostStmt(const CastExpr *CE, + CheckerContext &C) const { + const ObjCBridgedCastExpr *BE = dyn_cast<ObjCBridgedCastExpr>(CE); + if (!BE) + return; + + ArgEffect AE = IncRef; + + switch (BE->getBridgeKind()) { + case OBC_Bridge: + // Do nothing. + return; + case OBC_BridgeRetained: + AE = IncRef; + break; + case OBC_BridgeTransfer: + AE = DecRefBridgedTransferred; + break; + } + + ProgramStateRef state = C.getState(); + SymbolRef Sym = C.getSVal(CE).getAsLocSymbol(); + if (!Sym) + return; + const RefVal* T = getRefBinding(state, Sym); + if (!T) + return; + + RefVal::Kind hasErr = (RefVal::Kind) 0; + state = updateSymbol(state, Sym, *T, AE, hasErr, C); + + if (hasErr) { + // FIXME: If we get an error during a bridge cast, should we report it? + return; + } + + C.addTransition(state); +} + +void RetainCountChecker::processObjCLiterals(CheckerContext &C, + const Expr *Ex) const { + ProgramStateRef state = C.getState(); + const ExplodedNode *pred = C.getPredecessor(); + for (const Stmt *Child : Ex->children()) { + SVal V = pred->getSVal(Child); + if (SymbolRef sym = V.getAsSymbol()) + if (const RefVal* T = getRefBinding(state, sym)) { + RefVal::Kind hasErr = (RefVal::Kind) 0; + state = updateSymbol(state, sym, *T, MayEscape, hasErr, C); + if (hasErr) { + processNonLeakError(state, Child->getSourceRange(), hasErr, sym, C); + return; + } + } + } + + // Return the object as autoreleased. + // RetEffect RE = RetEffect::MakeNotOwned(RetEffect::ObjC); + if (SymbolRef sym = + state->getSVal(Ex, pred->getLocationContext()).getAsSymbol()) { + QualType ResultTy = Ex->getType(); + state = setRefBinding(state, sym, + RefVal::makeNotOwned(RetEffect::ObjC, ResultTy)); + } + + C.addTransition(state); +} + +void RetainCountChecker::checkPostStmt(const ObjCArrayLiteral *AL, + CheckerContext &C) const { + // Apply the 'MayEscape' to all values. + processObjCLiterals(C, AL); +} + +void RetainCountChecker::checkPostStmt(const ObjCDictionaryLiteral *DL, + CheckerContext &C) const { + // Apply the 'MayEscape' to all keys and values. + processObjCLiterals(C, DL); +} + +void RetainCountChecker::checkPostStmt(const ObjCBoxedExpr *Ex, + CheckerContext &C) const { + const ExplodedNode *Pred = C.getPredecessor(); + ProgramStateRef State = Pred->getState(); + + if (SymbolRef Sym = Pred->getSVal(Ex).getAsSymbol()) { + QualType ResultTy = Ex->getType(); + State = setRefBinding(State, Sym, + RefVal::makeNotOwned(RetEffect::ObjC, ResultTy)); + } + + C.addTransition(State); +} + +void RetainCountChecker::checkPostStmt(const ObjCIvarRefExpr *IRE, + CheckerContext &C) const { + Optional<Loc> IVarLoc = C.getSVal(IRE).getAs<Loc>(); + if (!IVarLoc) + return; + + ProgramStateRef State = C.getState(); + SymbolRef Sym = State->getSVal(*IVarLoc).getAsSymbol(); + if (!Sym || !dyn_cast_or_null<ObjCIvarRegion>(Sym->getOriginRegion())) + return; + + // Accessing an ivar directly is unusual. If we've done that, be more + // forgiving about what the surrounding code is allowed to do. + + QualType Ty = Sym->getType(); + RetEffect::ObjKind Kind; + if (Ty->isObjCRetainableType()) + Kind = RetEffect::ObjC; + else if (coreFoundation::isCFObjectRef(Ty)) + Kind = RetEffect::CF; + else + return; + + // If the value is already known to be nil, don't bother tracking it. + ConstraintManager &CMgr = State->getConstraintManager(); + if (CMgr.isNull(State, Sym).isConstrainedTrue()) + return; + + if (const RefVal *RV = getRefBinding(State, Sym)) { + // If we've seen this symbol before, or we're only seeing it now because + // of something the analyzer has synthesized, don't do anything. + if (RV->getIvarAccessHistory() != RefVal::IvarAccessHistory::None || + isSynthesizedAccessor(C.getStackFrame())) { + return; + } + + // Note that this value has been loaded from an ivar. + C.addTransition(setRefBinding(State, Sym, RV->withIvarAccess())); + return; + } + + RefVal PlusZero = RefVal::makeNotOwned(Kind, Ty); + + // In a synthesized accessor, the effective retain count is +0. + if (isSynthesizedAccessor(C.getStackFrame())) { + C.addTransition(setRefBinding(State, Sym, PlusZero)); + return; + } + + State = setRefBinding(State, Sym, PlusZero.withIvarAccess()); + C.addTransition(State); +} + +void RetainCountChecker::checkPostCall(const CallEvent &Call, + CheckerContext &C) const { + RetainSummaryManager &Summaries = getSummaryManager(C); + const RetainSummary *Summ = Summaries.getSummary(Call, C.getState()); + + if (C.wasInlined) { + processSummaryOfInlined(*Summ, Call, C); + return; + } + checkSummary(*Summ, Call, C); +} + +/// 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 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). +// FIXME: We may be able to do this with related result types instead. +// This function is probably overestimating. +static QualType GetReturnType(const Expr *RetE, ASTContext &Ctx) { + QualType RetTy = RetE->getType(); + // If RetE is not a message expression just return its type. + // If RetE is a message expression, return its types if it is something + /// more specific than id. + if (const ObjCMessageExpr *ME = dyn_cast<ObjCMessageExpr>(RetE)) + if (const ObjCObjectPointerType *PT = RetTy->getAs<ObjCObjectPointerType>()) + if (PT->isObjCQualifiedIdType() || PT->isObjCIdType() || + PT->isObjCClassType()) { + // At this point we know the return type of the message expression is + // id, id<...>, or Class. If we have an ObjCInterfaceDecl, we know this + // is a call to a class method whose type we can resolve. In such + // cases, promote the return type to XXX* (where XXX is the class). + const ObjCInterfaceDecl *D = ME->getReceiverInterface(); + return !D ? RetTy : + Ctx.getObjCObjectPointerType(Ctx.getObjCInterfaceType(D)); + } + + return RetTy; +} + +// We don't always get the exact modeling of the function with regards to the +// retain count checker even when the function is inlined. For example, we need +// to stop tracking the symbols which were marked with StopTrackingHard. +void RetainCountChecker::processSummaryOfInlined(const RetainSummary &Summ, + const CallEvent &CallOrMsg, + CheckerContext &C) const { + ProgramStateRef state = C.getState(); + + // Evaluate the effect of the arguments. + for (unsigned idx = 0, e = CallOrMsg.getNumArgs(); idx != e; ++idx) { + if (Summ.getArg(idx) == StopTrackingHard) { + SVal V = CallOrMsg.getArgSVal(idx); + if (SymbolRef Sym = V.getAsLocSymbol()) { + state = removeRefBinding(state, Sym); + } + } + } + + // Evaluate the effect on the message receiver. + const ObjCMethodCall *MsgInvocation = dyn_cast<ObjCMethodCall>(&CallOrMsg); + if (MsgInvocation) { + if (SymbolRef Sym = MsgInvocation->getReceiverSVal().getAsLocSymbol()) { + if (Summ.getReceiverEffect() == StopTrackingHard) { + state = removeRefBinding(state, Sym); + } + } + } + + // Consult the summary for the return value. + RetEffect RE = Summ.getRetEffect(); + if (RE.getKind() == RetEffect::NoRetHard) { + SymbolRef Sym = CallOrMsg.getReturnValue().getAsSymbol(); + if (Sym) + state = removeRefBinding(state, Sym); + } + + C.addTransition(state); +} + +static ProgramStateRef updateOutParameter(ProgramStateRef State, + SVal ArgVal, + ArgEffect Effect) { + auto *ArgRegion = dyn_cast_or_null<TypedValueRegion>(ArgVal.getAsRegion()); + if (!ArgRegion) + return State; + + QualType PointeeTy = ArgRegion->getValueType(); + if (!coreFoundation::isCFObjectRef(PointeeTy)) + return State; + + SVal PointeeVal = State->getSVal(ArgRegion); + SymbolRef Pointee = PointeeVal.getAsLocSymbol(); + if (!Pointee) + return State; + + switch (Effect) { + case UnretainedOutParameter: + State = setRefBinding(State, Pointee, + RefVal::makeNotOwned(RetEffect::CF, PointeeTy)); + break; + case RetainedOutParameter: + // Do nothing. Retained out parameters will either point to a +1 reference + // or NULL, but the way you check for failure differs depending on the API. + // Consequently, we don't have a good way to track them yet. + break; + + default: + llvm_unreachable("only for out parameters"); + } + + return State; +} + +void RetainCountChecker::checkSummary(const RetainSummary &Summ, + const CallEvent &CallOrMsg, + CheckerContext &C) const { + ProgramStateRef state = C.getState(); + + // Evaluate the effect of the arguments. + RefVal::Kind hasErr = (RefVal::Kind) 0; + SourceRange ErrorRange; + SymbolRef ErrorSym = nullptr; + + for (unsigned idx = 0, e = CallOrMsg.getNumArgs(); idx != e; ++idx) { + SVal V = CallOrMsg.getArgSVal(idx); + + ArgEffect Effect = Summ.getArg(idx); + if (Effect == RetainedOutParameter || Effect == UnretainedOutParameter) { + state = updateOutParameter(state, V, Effect); + } else if (SymbolRef Sym = V.getAsLocSymbol()) { + if (const RefVal *T = getRefBinding(state, Sym)) { + state = updateSymbol(state, Sym, *T, Effect, hasErr, C); + if (hasErr) { + ErrorRange = CallOrMsg.getArgSourceRange(idx); + ErrorSym = Sym; + break; + } + } + } + } + + // Evaluate the effect on the message receiver. + bool ReceiverIsTracked = false; + if (!hasErr) { + const ObjCMethodCall *MsgInvocation = dyn_cast<ObjCMethodCall>(&CallOrMsg); + if (MsgInvocation) { + if (SymbolRef Sym = MsgInvocation->getReceiverSVal().getAsLocSymbol()) { + if (const RefVal *T = getRefBinding(state, Sym)) { + ReceiverIsTracked = true; + state = updateSymbol(state, Sym, *T, Summ.getReceiverEffect(), + hasErr, C); + if (hasErr) { + ErrorRange = MsgInvocation->getOriginExpr()->getReceiverRange(); + ErrorSym = Sym; + } + } + } + } + } + + // Process any errors. + if (hasErr) { + processNonLeakError(state, ErrorRange, hasErr, ErrorSym, C); + return; + } + + // Consult the summary for the return value. + RetEffect RE = Summ.getRetEffect(); + + if (RE.getKind() == RetEffect::OwnedWhenTrackedReceiver) { + if (ReceiverIsTracked) + RE = getSummaryManager(C).getObjAllocRetEffect(); + else + RE = RetEffect::MakeNoRet(); + } + + switch (RE.getKind()) { + default: + llvm_unreachable("Unhandled RetEffect."); + + case RetEffect::NoRet: + case RetEffect::NoRetHard: + // No work necessary. + break; + + case RetEffect::OwnedSymbol: { + SymbolRef Sym = CallOrMsg.getReturnValue().getAsSymbol(); + if (!Sym) + break; + + // Use the result type from the CallEvent as it automatically adjusts + // for methods/functions that return references. + QualType ResultTy = CallOrMsg.getResultType(); + state = setRefBinding(state, Sym, RefVal::makeOwned(RE.getObjKind(), + ResultTy)); + + // FIXME: Add a flag to the checker where allocations are assumed to + // *not* fail. + break; + } + + case RetEffect::NotOwnedSymbol: { + const Expr *Ex = CallOrMsg.getOriginExpr(); + SymbolRef Sym = CallOrMsg.getReturnValue().getAsSymbol(); + if (!Sym) + break; + assert(Ex); + // Use GetReturnType in order to give [NSFoo alloc] the type NSFoo *. + QualType ResultTy = GetReturnType(Ex, C.getASTContext()); + state = setRefBinding(state, Sym, RefVal::makeNotOwned(RE.getObjKind(), + ResultTy)); + break; + } + } + + // This check is actually necessary; otherwise the statement builder thinks + // we've hit a previously-found path. + // Normally addTransition takes care of this, but we want the node pointer. + ExplodedNode *NewNode; + if (state == C.getState()) { + NewNode = C.getPredecessor(); + } else { + NewNode = C.addTransition(state); + } + + // Annotate the node with summary we used. + if (NewNode) { + // FIXME: This is ugly. See checkEndAnalysis for why it's necessary. + if (ShouldResetSummaryLog) { + SummaryLog.clear(); + ShouldResetSummaryLog = false; + } + SummaryLog[NewNode] = &Summ; + } +} + +ProgramStateRef +RetainCountChecker::updateSymbol(ProgramStateRef state, SymbolRef sym, + RefVal V, ArgEffect E, RefVal::Kind &hasErr, + CheckerContext &C) const { + bool IgnoreRetainMsg = (bool)C.getASTContext().getLangOpts().ObjCAutoRefCount; + switch (E) { + default: + break; + case IncRefMsg: + E = IgnoreRetainMsg ? DoNothing : IncRef; + break; + case DecRefMsg: + E = IgnoreRetainMsg ? DoNothing: DecRef; + break; + case DecRefMsgAndStopTrackingHard: + E = IgnoreRetainMsg ? StopTracking : DecRefAndStopTrackingHard; + break; + } + + // Handle all use-after-releases. + if (V.getKind() == RefVal::Released) { + V = V ^ RefVal::ErrorUseAfterRelease; + hasErr = V.getKind(); + return setRefBinding(state, sym, V); + } + + switch (E) { + case DecRefMsg: + case IncRefMsg: + case DecRefMsgAndStopTrackingHard: + llvm_unreachable("DecRefMsg/IncRefMsg already converted"); + + case UnretainedOutParameter: + case RetainedOutParameter: + llvm_unreachable("Applies to pointer-to-pointer parameters, which should " + "not have ref state."); + + case Dealloc: + switch (V.getKind()) { + default: + llvm_unreachable("Invalid RefVal state for an explicit dealloc."); + case RefVal::Owned: + // The object immediately transitions to the released state. + V = V ^ RefVal::Released; + V.clearCounts(); + return setRefBinding(state, sym, V); + case RefVal::NotOwned: + V = V ^ RefVal::ErrorDeallocNotOwned; + hasErr = V.getKind(); + break; + } + break; + + case MayEscape: + if (V.getKind() == RefVal::Owned) { + V = V ^ RefVal::NotOwned; + break; + } + + // Fall-through. + + case DoNothing: + return state; + + case Autorelease: + // Update the autorelease counts. + V = V.autorelease(); + break; + + case StopTracking: + case StopTrackingHard: + return removeRefBinding(state, sym); + + case IncRef: + switch (V.getKind()) { + default: + llvm_unreachable("Invalid RefVal state for a retain."); + case RefVal::Owned: + case RefVal::NotOwned: + V = V + 1; + break; + } + break; + + case DecRef: + case DecRefBridgedTransferred: + case DecRefAndStopTrackingHard: + switch (V.getKind()) { + default: + // case 'RefVal::Released' handled above. + llvm_unreachable("Invalid RefVal state for a release."); + + case RefVal::Owned: + assert(V.getCount() > 0); + if (V.getCount() == 1) { + if (E == DecRefBridgedTransferred || + V.getIvarAccessHistory() == + RefVal::IvarAccessHistory::AccessedDirectly) + V = V ^ RefVal::NotOwned; + else + V = V ^ RefVal::Released; + } else if (E == DecRefAndStopTrackingHard) { + return removeRefBinding(state, sym); + } + + V = V - 1; + break; + + case RefVal::NotOwned: + if (V.getCount() > 0) { + if (E == DecRefAndStopTrackingHard) + return removeRefBinding(state, sym); + V = V - 1; + } else if (V.getIvarAccessHistory() == + RefVal::IvarAccessHistory::AccessedDirectly) { + // Assume that the instance variable was holding on the object at + // +1, and we just didn't know. + if (E == DecRefAndStopTrackingHard) + return removeRefBinding(state, sym); + V = V.releaseViaIvar() ^ RefVal::Released; + } else { + V = V ^ RefVal::ErrorReleaseNotOwned; + hasErr = V.getKind(); + } + break; + } + break; + } + return setRefBinding(state, sym, V); +} + +void RetainCountChecker::processNonLeakError(ProgramStateRef St, + SourceRange ErrorRange, + RefVal::Kind ErrorKind, + SymbolRef Sym, + CheckerContext &C) const { + // HACK: Ignore retain-count issues on values accessed through ivars, + // because of cases like this: + // [_contentView retain]; + // [_contentView removeFromSuperview]; + // [self addSubview:_contentView]; // invalidates 'self' + // [_contentView release]; + if (const RefVal *RV = getRefBinding(St, Sym)) + if (RV->getIvarAccessHistory() != RefVal::IvarAccessHistory::None) + return; + + ExplodedNode *N = C.generateErrorNode(St); + if (!N) + return; + + CFRefBug *BT; + switch (ErrorKind) { + default: + llvm_unreachable("Unhandled error."); + case RefVal::ErrorUseAfterRelease: + if (!useAfterRelease) + useAfterRelease.reset(new UseAfterRelease(this)); + BT = useAfterRelease.get(); + break; + case RefVal::ErrorReleaseNotOwned: + if (!releaseNotOwned) + releaseNotOwned.reset(new BadRelease(this)); + BT = releaseNotOwned.get(); + break; + case RefVal::ErrorDeallocNotOwned: + if (!deallocNotOwned) + deallocNotOwned.reset(new DeallocNotOwned(this)); + BT = deallocNotOwned.get(); + break; + } + + assert(BT); + auto report = std::unique_ptr<BugReport>( + new CFRefReport(*BT, C.getASTContext().getLangOpts(), + SummaryLog, N, Sym)); + report->addRange(ErrorRange); + C.emitReport(std::move(report)); +} + +//===----------------------------------------------------------------------===// +// Handle the return values of retain-count-related functions. +//===----------------------------------------------------------------------===// + +bool RetainCountChecker::evalCall(const CallExpr *CE, CheckerContext &C) const { + // Get the callee. We're only interested in simple C functions. + ProgramStateRef state = C.getState(); + const FunctionDecl *FD = C.getCalleeDecl(CE); + if (!FD) + return false; + + IdentifierInfo *II = FD->getIdentifier(); + if (!II) + return false; + + // For now, we're only handling the functions that return aliases of their + // arguments: CFRetain (and its families). + // Eventually we should add other functions we can model entirely, + // such as CFRelease, which don't invalidate their arguments or globals. + if (CE->getNumArgs() != 1) + return false; + + // Get the name of the function. + StringRef FName = II->getName(); + FName = FName.substr(FName.find_first_not_of('_')); + + // See if it's one of the specific functions we know how to eval. + bool canEval = false; + // See if the function has 'rc_ownership_trusted_implementation' + // annotate attribute. If it does, we will not inline it. + bool hasTrustedImplementationAnnotation = false; + + QualType ResultTy = CE->getCallReturnType(C.getASTContext()); + if (ResultTy->isPointerType()) { + // Handle: (CF|CG|CV)Retain + // CFAutorelease + // It's okay to be a little sloppy here. + if (cocoa::isRefType(ResultTy, "CF", FName) || + cocoa::isRefType(ResultTy, "CG", FName) || + cocoa::isRefType(ResultTy, "CV", FName)) { + canEval = RetainSummary::isRetain(FD, FName) || + RetainSummary::isAutorelease(FD, FName); + } else { + if (FD->getDefinition()) { + canEval = RetainSummary::isTrustedReferenceCountImplementation( + FD->getDefinition()); + hasTrustedImplementationAnnotation = canEval; + } + } + } + + if (!canEval) + return false; + + // Bind the return value. + const LocationContext *LCtx = C.getLocationContext(); + SVal RetVal = state->getSVal(CE->getArg(0), LCtx); + if (RetVal.isUnknown() || + (hasTrustedImplementationAnnotation && !ResultTy.isNull())) { + // If the receiver is unknown or the function has + // 'rc_ownership_trusted_implementation' annotate attribute, conjure a + // return value. + SValBuilder &SVB = C.getSValBuilder(); + RetVal = SVB.conjureSymbolVal(nullptr, CE, LCtx, ResultTy, C.blockCount()); + } + state = state->BindExpr(CE, LCtx, RetVal, false); + + // FIXME: This should not be necessary, but otherwise the argument seems to be + // considered alive during the next statement. + if (const MemRegion *ArgRegion = RetVal.getAsRegion()) { + // Save the refcount status of the argument. + SymbolRef Sym = RetVal.getAsLocSymbol(); + const RefVal *Binding = nullptr; + if (Sym) + Binding = getRefBinding(state, Sym); + + // Invalidate the argument region. + state = state->invalidateRegions( + ArgRegion, CE, C.blockCount(), LCtx, + /*CausesPointerEscape*/ hasTrustedImplementationAnnotation); + + // Restore the refcount status of the argument. + if (Binding) + state = setRefBinding(state, Sym, *Binding); + } + + C.addTransition(state); + return true; +} + +//===----------------------------------------------------------------------===// +// Handle return statements. +//===----------------------------------------------------------------------===// + +void RetainCountChecker::checkPreStmt(const ReturnStmt *S, + CheckerContext &C) const { + + // Only adjust the reference count if this is the top-level call frame, + // and not the result of inlining. In the future, we should do + // better checking even for inlined calls, and see if they match + // with their expected semantics (e.g., the method should return a retained + // object, etc.). + if (!C.inTopFrame()) + return; + + const Expr *RetE = S->getRetValue(); + if (!RetE) + return; + + ProgramStateRef state = C.getState(); + SymbolRef Sym = + state->getSValAsScalarOrLoc(RetE, C.getLocationContext()).getAsLocSymbol(); + if (!Sym) + return; + + // Get the reference count binding (if any). + const RefVal *T = getRefBinding(state, 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.setCount(cnt - 1); + X = X ^ RefVal::ReturnedOwned; + break; + } + + case RefVal::NotOwned: { + unsigned cnt = X.getCount(); + if (cnt) { + X.setCount(cnt - 1); + X = X ^ RefVal::ReturnedOwned; + } + else { + X = X ^ RefVal::ReturnedNotOwned; + } + break; + } + + default: + return; + } + + // Update the binding. + state = setRefBinding(state, Sym, X); + ExplodedNode *Pred = C.addTransition(state); + + // At this point we have updated the state properly. + // Everything after this is merely checking to see if the return value has + // been over- or under-retained. + + // Did we cache out? + if (!Pred) + return; + + // Update the autorelease counts. + static CheckerProgramPointTag AutoreleaseTag(this, "Autorelease"); + state = handleAutoreleaseCounts(state, Pred, &AutoreleaseTag, C, Sym, X); + + // Did we cache out? + if (!state) + return; + + // Get the updated binding. + T = getRefBinding(state, Sym); + assert(T); + X = *T; + + // Consult the summary of the enclosing method. + RetainSummaryManager &Summaries = getSummaryManager(C); + const Decl *CD = &Pred->getCodeDecl(); + RetEffect RE = RetEffect::MakeNoRet(); + + // FIXME: What is the convention for blocks? Is there one? + if (const ObjCMethodDecl *MD = dyn_cast<ObjCMethodDecl>(CD)) { + const RetainSummary *Summ = Summaries.getMethodSummary(MD); + RE = Summ->getRetEffect(); + } else if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(CD)) { + if (!isa<CXXMethodDecl>(FD)) { + const RetainSummary *Summ = Summaries.getFunctionSummary(FD); + RE = Summ->getRetEffect(); + } + } + + checkReturnWithRetEffect(S, C, Pred, RE, X, Sym, state); +} + +void RetainCountChecker::checkReturnWithRetEffect(const ReturnStmt *S, + CheckerContext &C, + ExplodedNode *Pred, + RetEffect RE, RefVal X, + SymbolRef Sym, + ProgramStateRef state) const { + // HACK: Ignore retain-count issues on values accessed through ivars, + // because of cases like this: + // [_contentView retain]; + // [_contentView removeFromSuperview]; + // [self addSubview:_contentView]; // invalidates 'self' + // [_contentView release]; + if (X.getIvarAccessHistory() != RefVal::IvarAccessHistory::None) + return; + + // Any leaks or other errors? + if (X.isReturnedOwned() && X.getCount() == 0) { + if (RE.getKind() != RetEffect::NoRet) { + bool hasError = false; + if (!RE.isOwned()) { + // The returning type is a CF, we expect the enclosing method should + // return ownership. + hasError = true; + X = X ^ RefVal::ErrorLeakReturned; + } + + if (hasError) { + // Generate an error node. + state = setRefBinding(state, Sym, X); + + static CheckerProgramPointTag ReturnOwnLeakTag(this, "ReturnsOwnLeak"); + ExplodedNode *N = C.addTransition(state, Pred, &ReturnOwnLeakTag); + if (N) { + const LangOptions &LOpts = C.getASTContext().getLangOpts(); + C.emitReport(std::unique_ptr<BugReport>(new CFRefLeakReport( + *getLeakAtReturnBug(LOpts), LOpts, + SummaryLog, N, Sym, C, IncludeAllocationLine))); + } + } + } + } else if (X.isReturnedNotOwned()) { + if (RE.isOwned()) { + if (X.getIvarAccessHistory() == + RefVal::IvarAccessHistory::AccessedDirectly) { + // Assume the method was trying to transfer a +1 reference from a + // strong ivar to the caller. + state = setRefBinding(state, Sym, + X.releaseViaIvar() ^ RefVal::ReturnedOwned); + } else { + // Trying to return a not owned object to a caller expecting an + // owned object. + state = setRefBinding(state, Sym, X ^ RefVal::ErrorReturnedNotOwned); + + static CheckerProgramPointTag + ReturnNotOwnedTag(this, "ReturnNotOwnedForOwned"); + + ExplodedNode *N = C.addTransition(state, Pred, &ReturnNotOwnedTag); + if (N) { + if (!returnNotOwnedForOwned) + returnNotOwnedForOwned.reset(new ReturnedNotOwnedForOwned(this)); + + C.emitReport(std::unique_ptr<BugReport>(new CFRefReport( + *returnNotOwnedForOwned, C.getASTContext().getLangOpts(), + SummaryLog, N, Sym))); + } + } + } + } +} + +//===----------------------------------------------------------------------===// +// Check various ways a symbol can be invalidated. +//===----------------------------------------------------------------------===// + +void RetainCountChecker::checkBind(SVal loc, SVal val, const Stmt *S, + CheckerContext &C) const { + // Are we storing to something that causes the value to "escape"? + bool escapes = true; + + // 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. + ProgramStateRef state = C.getState(); + + if (Optional<loc::MemRegionVal> regionLoc = loc.getAs<loc::MemRegionVal>()) { + escapes = !regionLoc->getRegion()->hasStackStorage(); + + if (!escapes) { + // To test (3), generate a new state with the binding added. If it is + // the same state, then it escapes (since the store cannot represent + // the binding). + // Do this only if we know that the store is not supposed to generate the + // same state. + SVal StoredVal = state->getSVal(regionLoc->getRegion()); + if (StoredVal != val) + escapes = (state == (state->bindLoc(*regionLoc, val, C.getLocationContext()))); + } + if (!escapes) { + // Case 4: We do not currently model what happens when a symbol is + // assigned to a struct field, so be conservative here and let the symbol + // go. TODO: This could definitely be improved upon. + escapes = !isa<VarRegion>(regionLoc->getRegion()); + } + } + + // If we are storing the value into an auto function scope variable annotated + // with (__attribute__((cleanup))), stop tracking the value to avoid leak + // false positives. + if (const VarRegion *LVR = dyn_cast_or_null<VarRegion>(loc.getAsRegion())) { + const VarDecl *VD = LVR->getDecl(); + if (VD->hasAttr<CleanupAttr>()) { + escapes = true; + } + } + + // If our store can represent the binding and we aren't storing to something + // that doesn't have local storage then just return and have the simulation + // state continue as is. + if (!escapes) + return; + + // Otherwise, find all symbols referenced by 'val' that we are tracking + // and stop tracking them. + state = state->scanReachableSymbols<StopTrackingCallback>(val).getState(); + C.addTransition(state); +} + +ProgramStateRef RetainCountChecker::evalAssume(ProgramStateRef state, + SVal Cond, + bool Assumption) const { + // 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. + RefBindingsTy B = state->get<RefBindings>(); + + if (B.isEmpty()) + return state; + + bool changed = false; + RefBindingsTy::Factory &RefBFactory = state->get_context<RefBindings>(); + + for (RefBindingsTy::iterator I = B.begin(), E = B.end(); I != E; ++I) { + // Check if the symbol is null stop tracking the symbol. + ConstraintManager &CMgr = state->getConstraintManager(); + ConditionTruthVal AllocFailed = CMgr.isNull(state, I.getKey()); + if (AllocFailed.isConstrainedTrue()) { + changed = true; + B = RefBFactory.remove(B, I.getKey()); + } + } + + if (changed) + state = state->set<RefBindings>(B); + + return state; +} + +ProgramStateRef +RetainCountChecker::checkRegionChanges(ProgramStateRef state, + const InvalidatedSymbols *invalidated, + ArrayRef<const MemRegion *> ExplicitRegions, + ArrayRef<const MemRegion *> Regions, + const LocationContext *LCtx, + const CallEvent *Call) const { + if (!invalidated) + return state; + + llvm::SmallPtrSet<SymbolRef, 8> WhitelistedSymbols; + for (ArrayRef<const MemRegion *>::iterator I = ExplicitRegions.begin(), + E = ExplicitRegions.end(); I != E; ++I) { + if (const SymbolicRegion *SR = (*I)->StripCasts()->getAs<SymbolicRegion>()) + WhitelistedSymbols.insert(SR->getSymbol()); + } + + for (InvalidatedSymbols::const_iterator I=invalidated->begin(), + E = invalidated->end(); I!=E; ++I) { + SymbolRef sym = *I; + if (WhitelistedSymbols.count(sym)) + continue; + // Remove any existing reference-count binding. + state = removeRefBinding(state, sym); + } + return state; +} + +//===----------------------------------------------------------------------===// +// Handle dead symbols and end-of-path. +//===----------------------------------------------------------------------===// + +ProgramStateRef +RetainCountChecker::handleAutoreleaseCounts(ProgramStateRef state, + ExplodedNode *Pred, + const ProgramPointTag *Tag, + CheckerContext &Ctx, + SymbolRef Sym, RefVal V) const { + unsigned ACnt = V.getAutoreleaseCount(); + + // No autorelease counts? Nothing to be done. + if (!ACnt) + return state; + + unsigned Cnt = V.getCount(); + + // FIXME: Handle sending 'autorelease' to already released object. + + if (V.getKind() == RefVal::ReturnedOwned) + ++Cnt; + + // If we would over-release here, but we know the value came from an ivar, + // assume it was a strong ivar that's just been relinquished. + if (ACnt > Cnt && + V.getIvarAccessHistory() == RefVal::IvarAccessHistory::AccessedDirectly) { + V = V.releaseViaIvar(); + --ACnt; + } + + if (ACnt <= Cnt) { + if (ACnt == Cnt) { + V.clearCounts(); + if (V.getKind() == RefVal::ReturnedOwned) + V = V ^ RefVal::ReturnedNotOwned; + else + V = V ^ RefVal::NotOwned; + } else { + V.setCount(V.getCount() - ACnt); + V.setAutoreleaseCount(0); + } + return setRefBinding(state, Sym, V); + } + + // HACK: Ignore retain-count issues on values accessed through ivars, + // because of cases like this: + // [_contentView retain]; + // [_contentView removeFromSuperview]; + // [self addSubview:_contentView]; // invalidates 'self' + // [_contentView release]; + if (V.getIvarAccessHistory() != RefVal::IvarAccessHistory::None) + return state; + + // Woah! More autorelease counts then retain counts left. + // Emit hard error. + V = V ^ RefVal::ErrorOverAutorelease; + state = setRefBinding(state, Sym, V); + + ExplodedNode *N = Ctx.generateSink(state, Pred, Tag); + if (N) { + SmallString<128> sbuf; + llvm::raw_svector_ostream os(sbuf); + os << "Object was autoreleased "; + if (V.getAutoreleaseCount() > 1) + os << V.getAutoreleaseCount() << " times but the object "; + else + os << "but "; + os << "has a +" << V.getCount() << " retain count"; + + if (!overAutorelease) + overAutorelease.reset(new OverAutorelease(this)); + + const LangOptions &LOpts = Ctx.getASTContext().getLangOpts(); + Ctx.emitReport(std::unique_ptr<BugReport>( + new CFRefReport(*overAutorelease, LOpts, + SummaryLog, N, Sym, os.str()))); + } + + return nullptr; +} + +ProgramStateRef +RetainCountChecker::handleSymbolDeath(ProgramStateRef state, + SymbolRef sid, RefVal V, + SmallVectorImpl<SymbolRef> &Leaked) const { + bool hasLeak; + + // HACK: Ignore retain-count issues on values accessed through ivars, + // because of cases like this: + // [_contentView retain]; + // [_contentView removeFromSuperview]; + // [self addSubview:_contentView]; // invalidates 'self' + // [_contentView release]; + if (V.getIvarAccessHistory() != RefVal::IvarAccessHistory::None) + hasLeak = false; + else if (V.isOwned()) + hasLeak = true; + else if (V.isNotOwned() || V.isReturnedOwned()) + hasLeak = (V.getCount() > 0); + else + hasLeak = false; + + if (!hasLeak) + return removeRefBinding(state, sid); + + Leaked.push_back(sid); + return setRefBinding(state, sid, V ^ RefVal::ErrorLeak); +} + +ExplodedNode * +RetainCountChecker::processLeaks(ProgramStateRef state, + SmallVectorImpl<SymbolRef> &Leaked, + CheckerContext &Ctx, + ExplodedNode *Pred) const { + // Generate an intermediate node representing the leak point. + ExplodedNode *N = Ctx.addTransition(state, Pred); + + if (N) { + for (SmallVectorImpl<SymbolRef>::iterator + I = Leaked.begin(), E = Leaked.end(); I != E; ++I) { + + const LangOptions &LOpts = Ctx.getASTContext().getLangOpts(); + CFRefBug *BT = Pred ? getLeakWithinFunctionBug(LOpts) + : getLeakAtReturnBug(LOpts); + assert(BT && "BugType not initialized."); + + Ctx.emitReport(std::unique_ptr<BugReport>( + new CFRefLeakReport(*BT, LOpts, SummaryLog, N, *I, Ctx, + IncludeAllocationLine))); + } + } + + return N; +} + +static bool isGeneralizedObjectRef(QualType Ty) { + if (Ty.getAsString().substr(0, 4) == "isl_") + return true; + else + return false; +} + +void RetainCountChecker::checkBeginFunction(CheckerContext &Ctx) const { + if (!Ctx.inTopFrame()) + return; + + const LocationContext *LCtx = Ctx.getLocationContext(); + const FunctionDecl *FD = dyn_cast<FunctionDecl>(LCtx->getDecl()); + + if (!FD || RetainSummary::isTrustedReferenceCountImplementation(FD)) + return; + + ProgramStateRef state = Ctx.getState(); + + const RetainSummary *FunctionSummary = + getSummaryManager(Ctx).getFunctionSummary(FD); + ArgEffects CalleeSideArgEffects = FunctionSummary->getArgEffects(); + + for (unsigned idx = 0, e = FD->getNumParams(); idx != e; ++idx) { + const ParmVarDecl *Param = FD->getParamDecl(idx); + SymbolRef Sym = state->getSVal(state->getRegion(Param, LCtx)).getAsSymbol(); + + QualType Ty = Param->getType(); + const ArgEffect *AE = CalleeSideArgEffects.lookup(idx); + if (AE && *AE == DecRef && isGeneralizedObjectRef(Ty)) { + state = setRefBinding(state, Sym, RefVal::makeOwned(RetEffect::ObjKind::Generalized, Ty)); + } else if (isGeneralizedObjectRef(Ty)) { + state = setRefBinding( + state, Sym, + RefVal::makeNotOwned(RetEffect::ObjKind::Generalized, Ty)); + } + } + + Ctx.addTransition(state); +} + +void RetainCountChecker::checkEndFunction(const ReturnStmt *RS, + CheckerContext &Ctx) const { + ProgramStateRef state = Ctx.getState(); + RefBindingsTy B = state->get<RefBindings>(); + ExplodedNode *Pred = Ctx.getPredecessor(); + + // Don't process anything within synthesized bodies. + const LocationContext *LCtx = Pred->getLocationContext(); + if (LCtx->getAnalysisDeclContext()->isBodyAutosynthesized()) { + assert(!LCtx->inTopFrame()); + return; + } + + for (RefBindingsTy::iterator I = B.begin(), E = B.end(); I != E; ++I) { + state = handleAutoreleaseCounts(state, Pred, /*Tag=*/nullptr, Ctx, + I->first, I->second); + if (!state) + return; + } + + // If the current LocationContext has a parent, don't check for leaks. + // We will do that later. + // FIXME: we should instead check for imbalances of the retain/releases, + // and suggest annotations. + if (LCtx->getParent()) + return; + + B = state->get<RefBindings>(); + SmallVector<SymbolRef, 10> Leaked; + + for (RefBindingsTy::iterator I = B.begin(), E = B.end(); I != E; ++I) + state = handleSymbolDeath(state, I->first, I->second, Leaked); + + processLeaks(state, Leaked, Ctx, Pred); +} + +const ProgramPointTag * +RetainCountChecker::getDeadSymbolTag(SymbolRef sym) const { + const CheckerProgramPointTag *&tag = DeadSymbolTags[sym]; + if (!tag) { + SmallString<64> buf; + llvm::raw_svector_ostream out(buf); + out << "Dead Symbol : "; + sym->dumpToStream(out); + tag = new CheckerProgramPointTag(this, out.str()); + } + return tag; +} + +void RetainCountChecker::checkDeadSymbols(SymbolReaper &SymReaper, + CheckerContext &C) const { + ExplodedNode *Pred = C.getPredecessor(); + + ProgramStateRef state = C.getState(); + RefBindingsTy B = state->get<RefBindings>(); + SmallVector<SymbolRef, 10> Leaked; + + // Update counts from autorelease pools + for (SymbolReaper::dead_iterator I = SymReaper.dead_begin(), + E = SymReaper.dead_end(); I != E; ++I) { + SymbolRef Sym = *I; + if (const RefVal *T = B.lookup(Sym)){ + // Use the symbol as the tag. + // FIXME: This might not be as unique as we would like. + const ProgramPointTag *Tag = getDeadSymbolTag(Sym); + state = handleAutoreleaseCounts(state, Pred, Tag, C, Sym, *T); + if (!state) + return; + + // Fetch the new reference count from the state, and use it to handle + // this symbol. + state = handleSymbolDeath(state, *I, *getRefBinding(state, Sym), Leaked); + } + } + + if (Leaked.empty()) { + C.addTransition(state); + return; + } + + Pred = processLeaks(state, Leaked, C, Pred); + + // Did we cache out? + if (!Pred) + return; + + // Now generate a new node that nukes the old bindings. + // The only bindings left at this point are the leaked symbols. + RefBindingsTy::Factory &F = state->get_context<RefBindings>(); + B = state->get<RefBindings>(); + + for (SmallVectorImpl<SymbolRef>::iterator I = Leaked.begin(), + E = Leaked.end(); + I != E; ++I) + B = F.remove(B, *I); + + state = state->set<RefBindings>(B); + C.addTransition(state, Pred); +} + +void RetainCountChecker::printState(raw_ostream &Out, ProgramStateRef State, + const char *NL, const char *Sep) const { + + RefBindingsTy B = State->get<RefBindings>(); + + if (B.isEmpty()) + return; + + Out << Sep << NL; + + for (RefBindingsTy::iterator I = B.begin(), E = B.end(); I != E; ++I) { + Out << I->first << " : "; + I->second.print(Out); + Out << NL; + } +} + +//===----------------------------------------------------------------------===// +// Implementation of the CallEffects API. +//===----------------------------------------------------------------------===// + +namespace clang { +namespace ento { +namespace objc_retain { + +// This is a bit gross, but it allows us to populate CallEffects without +// creating a bunch of accessors. This kind is very localized, so the +// damage of this macro is limited. +#define createCallEffect(D, KIND)\ + ASTContext &Ctx = D->getASTContext();\ + LangOptions L = Ctx.getLangOpts();\ + RetainSummaryManager M(Ctx, L.ObjCAutoRefCount);\ + const RetainSummary *S = M.get ## KIND ## Summary(D);\ + CallEffects CE(S->getRetEffect());\ + CE.Receiver = S->getReceiverEffect();\ + unsigned N = D->param_size();\ + for (unsigned i = 0; i < N; ++i) {\ + CE.Args.push_back(S->getArg(i));\ + } + +CallEffects CallEffects::getEffect(const ObjCMethodDecl *MD) { + createCallEffect(MD, Method); + return CE; +} + +CallEffects CallEffects::getEffect(const FunctionDecl *FD) { + createCallEffect(FD, Function); + return CE; +} + +#undef createCallEffect + +} // end namespace objc_retain +} // end namespace ento +} // end namespace clang + +//===----------------------------------------------------------------------===// +// Checker registration. +//===----------------------------------------------------------------------===// + +void ento::registerRetainCountChecker(CheckerManager &Mgr) { + Mgr.registerChecker<RetainCountChecker>(Mgr.getAnalyzerOptions()); +} diff --git a/clang/lib/StaticAnalyzer/Checkers/RetainCountChecker/RetainCountChecker.h b/clang/lib/StaticAnalyzer/Checkers/RetainCountChecker/RetainCountChecker.h new file mode 100644 index 00000000000..c1d6b4d0ebc --- /dev/null +++ b/clang/lib/StaticAnalyzer/Checkers/RetainCountChecker/RetainCountChecker.h @@ -0,0 +1,446 @@ +//==--- RetainCountChecker.h - Checks for leaks and other issues -*- 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 RetainCountChecker, which implements +// a reference count checker for Core Foundation and Cocoa on (Mac OS X). +// +//===----------------------------------------------------------------------===// + +#ifndef LLVM_CLANG_LIB_STATICANALYZER_CHECKERS_RETAINCOUNTCHECKER_H +#define LLVM_CLANG_LIB_STATICANALYZER_CHECKERS_RETAINCOUNTCHECKER_H + +#include "../ClangSACheckers.h" +#include "../AllocationDiagnostics.h" +#include "../SelectorExtras.h" +#include "RetainCountSummaries.h" +#include "RetainCountDiagnostics.h" +#include "clang/AST/Attr.h" +#include "clang/AST/DeclCXX.h" +#include "clang/AST/DeclObjC.h" +#include "clang/AST/ParentMap.h" +#include "clang/Analysis/DomainSpecific/CocoaConventions.h" +#include "clang/Basic/LangOptions.h" +#include "clang/Basic/SourceManager.h" +#include "clang/StaticAnalyzer/Checkers/ObjCRetainCount.h" +#include "clang/StaticAnalyzer/Core/BugReporter/BugType.h" +#include "clang/StaticAnalyzer/Core/BugReporter/PathDiagnostic.h" +#include "clang/StaticAnalyzer/Core/Checker.h" +#include "clang/StaticAnalyzer/Core/CheckerManager.h" +#include "clang/StaticAnalyzer/Core/PathSensitive/CallEvent.h" +#include "clang/StaticAnalyzer/Core/PathSensitive/CheckerContext.h" +#include "clang/StaticAnalyzer/Core/PathSensitive/ProgramStateTrait.h" +#include "clang/StaticAnalyzer/Core/PathSensitive/SymbolManager.h" +#include "llvm/ADT/DenseMap.h" +#include "llvm/ADT/FoldingSet.h" +#include "llvm/ADT/ImmutableList.h" +#include "llvm/ADT/ImmutableMap.h" +#include "llvm/ADT/STLExtras.h" +#include "llvm/ADT/SmallString.h" +#include "llvm/ADT/StringExtras.h" +#include <cstdarg> +#include <utility> + +using namespace objc_retain; +using llvm::StrInStrNoCase; + +namespace clang { +namespace ento { +namespace retaincountchecker { + +/// Metadata on reference. +class 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. + ERROR_START, + ErrorDeallocNotOwned, // -dealloc called on non-owned object. + ErrorUseAfterRelease, // Object used after released. + ErrorReleaseNotOwned, // Release of an object that was not owned. + ERROR_LEAK_START, + ErrorLeak, // A memory leak due to excessive reference counts. + ErrorLeakReturned, // A memory leak due to the returning method not having + // the correct naming conventions. + ErrorOverAutorelease, + ErrorReturnedNotOwned + }; + + /// Tracks how an object referenced by an ivar has been used. + /// + /// This accounts for us not knowing if an arbitrary ivar is supposed to be + /// stored at +0 or +1. + enum class IvarAccessHistory { + None, + AccessedDirectly, + ReleasedAfterDirectAccess + }; + +private: + /// The number of outstanding retains. + unsigned Cnt; + /// The number of outstanding autoreleases. + unsigned ACnt; + /// The (static) type of the object at the time we started tracking it. + QualType T; + + /// The current state of the object. + /// + /// See the RefVal::Kind enum for possible values. + unsigned RawKind : 5; + + /// The kind of object being tracked (CF or ObjC), if known. + /// + /// See the RetEffect::ObjKind enum for possible values. + unsigned RawObjectKind : 2; + + /// True if the current state and/or retain count may turn out to not be the + /// best possible approximation of the reference counting state. + /// + /// If true, the checker may decide to throw away ("override") this state + /// in favor of something else when it sees the object being used in new ways. + /// + /// This setting should not be propagated to state derived from this state. + /// Once we start deriving new states, it would be inconsistent to override + /// them. + unsigned RawIvarAccessHistory : 2; + + RefVal(Kind k, RetEffect::ObjKind o, unsigned cnt, unsigned acnt, QualType t, + IvarAccessHistory IvarAccess) + : Cnt(cnt), ACnt(acnt), T(t), RawKind(static_cast<unsigned>(k)), + RawObjectKind(static_cast<unsigned>(o)), + RawIvarAccessHistory(static_cast<unsigned>(IvarAccess)) { + assert(getKind() == k && "not enough bits for the kind"); + assert(getObjKind() == o && "not enough bits for the object kind"); + assert(getIvarAccessHistory() == IvarAccess && "not enough bits"); + } + +public: + Kind getKind() const { return static_cast<Kind>(RawKind); } + + RetEffect::ObjKind getObjKind() const { + return static_cast<RetEffect::ObjKind>(RawObjectKind); + } + + unsigned getCount() const { return Cnt; } + unsigned getAutoreleaseCount() const { return ACnt; } + unsigned getCombinedCounts() const { return Cnt + ACnt; } + void clearCounts() { + Cnt = 0; + ACnt = 0; + } + void setCount(unsigned i) { + Cnt = i; + } + void setAutoreleaseCount(unsigned i) { + ACnt = i; + } + + QualType getType() const { return T; } + + /// Returns what the analyzer knows about direct accesses to a particular + /// instance variable. + /// + /// If the object with this refcount wasn't originally from an Objective-C + /// ivar region, this should always return IvarAccessHistory::None. + IvarAccessHistory getIvarAccessHistory() const { + return static_cast<IvarAccessHistory>(RawIvarAccessHistory); + } + + bool isOwned() const { + return getKind() == Owned; + } + + bool isNotOwned() const { + return getKind() == NotOwned; + } + + bool isReturnedOwned() const { + return getKind() == ReturnedOwned; + } + + bool isReturnedNotOwned() const { + return getKind() == ReturnedNotOwned; + } + + /// Create a state for an object whose lifetime is the responsibility of the + /// current function, at least partially. + /// + /// Most commonly, this is an owned object with a retain count of +1. + static RefVal makeOwned(RetEffect::ObjKind o, QualType t) { + return RefVal(Owned, o, /*Count=*/1, 0, t, IvarAccessHistory::None); + } + + /// Create a state for an object whose lifetime is not the responsibility of + /// the current function. + /// + /// Most commonly, this is an unowned object with a retain count of +0. + static RefVal makeNotOwned(RetEffect::ObjKind o, QualType t) { + return RefVal(NotOwned, o, /*Count=*/0, 0, t, IvarAccessHistory::None); + } + + RefVal operator-(size_t i) const { + return RefVal(getKind(), getObjKind(), getCount() - i, + getAutoreleaseCount(), getType(), getIvarAccessHistory()); + } + + RefVal operator+(size_t i) const { + return RefVal(getKind(), getObjKind(), getCount() + i, + getAutoreleaseCount(), getType(), getIvarAccessHistory()); + } + + RefVal operator^(Kind k) const { + return RefVal(k, getObjKind(), getCount(), getAutoreleaseCount(), + getType(), getIvarAccessHistory()); + } + + RefVal autorelease() const { + return RefVal(getKind(), getObjKind(), getCount(), getAutoreleaseCount()+1, + getType(), getIvarAccessHistory()); + } + + RefVal withIvarAccess() const { + assert(getIvarAccessHistory() == IvarAccessHistory::None); + return RefVal(getKind(), getObjKind(), getCount(), getAutoreleaseCount(), + getType(), IvarAccessHistory::AccessedDirectly); + } + + RefVal releaseViaIvar() const { + assert(getIvarAccessHistory() == IvarAccessHistory::AccessedDirectly); + return RefVal(getKind(), getObjKind(), getCount(), getAutoreleaseCount(), + getType(), IvarAccessHistory::ReleasedAfterDirectAccess); + } + + // Comparison, profiling, and pretty-printing. + + bool hasSameState(const RefVal &X) const { + return getKind() == X.getKind() && Cnt == X.Cnt && ACnt == X.ACnt && + getIvarAccessHistory() == X.getIvarAccessHistory(); + } + + bool operator==(const RefVal& X) const { + return T == X.T && hasSameState(X) && getObjKind() == X.getObjKind(); + } + + void Profile(llvm::FoldingSetNodeID& ID) const { + ID.Add(T); + ID.AddInteger(RawKind); + ID.AddInteger(Cnt); + ID.AddInteger(ACnt); + ID.AddInteger(RawObjectKind); + ID.AddInteger(RawIvarAccessHistory); + } + + void print(raw_ostream &Out) const; +}; + +class RetainCountChecker + : public Checker< check::Bind, + check::DeadSymbols, + check::EndAnalysis, + check::BeginFunction, + check::EndFunction, + check::PostStmt<BlockExpr>, + check::PostStmt<CastExpr>, + check::PostStmt<ObjCArrayLiteral>, + check::PostStmt<ObjCDictionaryLiteral>, + check::PostStmt<ObjCBoxedExpr>, + check::PostStmt<ObjCIvarRefExpr>, + check::PostCall, + check::PreStmt<ReturnStmt>, + check::RegionChanges, + eval::Assume, + eval::Call > { + mutable std::unique_ptr<CFRefBug> useAfterRelease, releaseNotOwned; + mutable std::unique_ptr<CFRefBug> deallocNotOwned; + mutable std::unique_ptr<CFRefBug> overAutorelease, returnNotOwnedForOwned; + mutable std::unique_ptr<CFRefBug> leakWithinFunction, leakAtReturn; + + typedef llvm::DenseMap<SymbolRef, const CheckerProgramPointTag *> SymbolTagMap; + + // This map is only used to ensure proper deletion of any allocated tags. + mutable SymbolTagMap DeadSymbolTags; + + mutable std::unique_ptr<RetainSummaryManager> Summaries; + mutable SummaryLogTy SummaryLog; + mutable bool ShouldResetSummaryLog; + + /// Optional setting to indicate if leak reports should include + /// the allocation line. + mutable bool IncludeAllocationLine; + +public: + RetainCountChecker(AnalyzerOptions &AO) + : ShouldResetSummaryLog(false), + IncludeAllocationLine(shouldIncludeAllocationSiteInLeakDiagnostics(AO)) {} + + ~RetainCountChecker() override { DeleteContainerSeconds(DeadSymbolTags); } + + void checkEndAnalysis(ExplodedGraph &G, BugReporter &BR, + ExprEngine &Eng) const { + // FIXME: This is a hack to make sure the summary log gets cleared between + // analyses of different code bodies. + // + // Why is this necessary? Because a checker's lifetime is tied to a + // translation unit, but an ExplodedGraph's lifetime is just a code body. + // Once in a blue moon, a new ExplodedNode will have the same address as an + // old one with an associated summary, and the bug report visitor gets very + // confused. (To make things worse, the summary lifetime is currently also + // tied to a code body, so we get a crash instead of incorrect results.) + // + // Why is this a bad solution? Because if the lifetime of the ExplodedGraph + // changes, things will start going wrong again. Really the lifetime of this + // log needs to be tied to either the specific nodes in it or the entire + // ExplodedGraph, not to a specific part of the code being analyzed. + // + // (Also, having stateful local data means that the same checker can't be + // used from multiple threads, but a lot of checkers have incorrect + // assumptions about that anyway. So that wasn't a priority at the time of + // this fix.) + // + // This happens at the end of analysis, but bug reports are emitted /after/ + // this point. So we can't just clear the summary log now. Instead, we mark + // that the next time we access the summary log, it should be cleared. + + // If we never reset the summary log during /this/ code body analysis, + // there were no new summaries. There might still have been summaries from + // the /last/ analysis, so clear them out to make sure the bug report + // visitors don't get confused. + if (ShouldResetSummaryLog) + SummaryLog.clear(); + + ShouldResetSummaryLog = !SummaryLog.empty(); + } + + CFRefBug *getLeakWithinFunctionBug(const LangOptions &LOpts) const { + if (!leakWithinFunction) + leakWithinFunction.reset(new Leak(this, "Leak")); + return leakWithinFunction.get(); + } + + CFRefBug *getLeakAtReturnBug(const LangOptions &LOpts) const { + if (!leakAtReturn) + leakAtReturn.reset(new Leak(this, "Leak of returned object")); + return leakAtReturn.get(); + } + + RetainSummaryManager &getSummaryManager(ASTContext &Ctx) const { + // FIXME: We don't support ARC being turned on and off during one analysis. + // (nor, for that matter, do we support changing ASTContexts) + bool ARCEnabled = (bool)Ctx.getLangOpts().ObjCAutoRefCount; + if (!Summaries) + Summaries.reset(new RetainSummaryManager(Ctx, ARCEnabled)); + else + assert(Summaries->isARCEnabled() == ARCEnabled); + return *Summaries; + } + + RetainSummaryManager &getSummaryManager(CheckerContext &C) const { + return getSummaryManager(C.getASTContext()); + } + + void printState(raw_ostream &Out, ProgramStateRef State, + const char *NL, const char *Sep) const override; + + void checkBind(SVal loc, SVal val, const Stmt *S, CheckerContext &C) const; + void checkPostStmt(const BlockExpr *BE, CheckerContext &C) const; + void checkPostStmt(const CastExpr *CE, CheckerContext &C) const; + + void checkPostStmt(const ObjCArrayLiteral *AL, CheckerContext &C) const; + void checkPostStmt(const ObjCDictionaryLiteral *DL, CheckerContext &C) const; + void checkPostStmt(const ObjCBoxedExpr *BE, CheckerContext &C) const; + + void checkPostStmt(const ObjCIvarRefExpr *IRE, CheckerContext &C) const; + + void checkPostCall(const CallEvent &Call, CheckerContext &C) const; + + void checkSummary(const RetainSummary &Summ, const CallEvent &Call, + CheckerContext &C) const; + + void processSummaryOfInlined(const RetainSummary &Summ, + const CallEvent &Call, + CheckerContext &C) const; + + bool evalCall(const CallExpr *CE, CheckerContext &C) const; + + ProgramStateRef evalAssume(ProgramStateRef state, SVal Cond, + bool Assumption) const; + + ProgramStateRef + checkRegionChanges(ProgramStateRef state, + const InvalidatedSymbols *invalidated, + ArrayRef<const MemRegion *> ExplicitRegions, + ArrayRef<const MemRegion *> Regions, + const LocationContext* LCtx, + const CallEvent *Call) const; + + void checkPreStmt(const ReturnStmt *S, CheckerContext &C) const; + void checkReturnWithRetEffect(const ReturnStmt *S, CheckerContext &C, + ExplodedNode *Pred, RetEffect RE, RefVal X, + SymbolRef Sym, ProgramStateRef state) const; + + void checkDeadSymbols(SymbolReaper &SymReaper, CheckerContext &C) const; + void checkBeginFunction(CheckerContext &C) const; + void checkEndFunction(const ReturnStmt *RS, CheckerContext &C) const; + + ProgramStateRef updateSymbol(ProgramStateRef state, SymbolRef sym, + RefVal V, ArgEffect E, RefVal::Kind &hasErr, + CheckerContext &C) const; + + void processNonLeakError(ProgramStateRef St, SourceRange ErrorRange, + RefVal::Kind ErrorKind, SymbolRef Sym, + CheckerContext &C) const; + + void processObjCLiterals(CheckerContext &C, const Expr *Ex) const; + + const ProgramPointTag *getDeadSymbolTag(SymbolRef sym) const; + + ProgramStateRef handleSymbolDeath(ProgramStateRef state, + SymbolRef sid, RefVal V, + SmallVectorImpl<SymbolRef> &Leaked) const; + + ProgramStateRef + handleAutoreleaseCounts(ProgramStateRef state, ExplodedNode *Pred, + const ProgramPointTag *Tag, CheckerContext &Ctx, + SymbolRef Sym, RefVal V) const; + + ExplodedNode *processLeaks(ProgramStateRef state, + SmallVectorImpl<SymbolRef> &Leaked, + CheckerContext &Ctx, + ExplodedNode *Pred = nullptr) const; +}; + +//===----------------------------------------------------------------------===// +// RefBindings - State used to track object reference counts. +//===----------------------------------------------------------------------===// + +const RefVal *getRefBinding(ProgramStateRef State, SymbolRef Sym); + +ProgramStateRef setRefBinding(ProgramStateRef State, SymbolRef Sym, + RefVal Val); + +ProgramStateRef removeRefBinding(ProgramStateRef State, SymbolRef Sym); + +/// Returns true if this stack frame is for an Objective-C method that is a +/// property getter or setter whose body has been synthesized by the analyzer. +inline bool isSynthesizedAccessor(const StackFrameContext *SFC) { + auto Method = dyn_cast_or_null<ObjCMethodDecl>(SFC->getDecl()); + if (!Method || !Method->isPropertyAccessor()) + return false; + + return SFC->getAnalysisDeclContext()->isBodyAutosynthesized(); +} + +} // end namespace retaincountchecker +} // end namespace ento +} // end namespace clang + +#endif diff --git a/clang/lib/StaticAnalyzer/Checkers/RetainCountChecker/RetainCountDiagnostics.cpp b/clang/lib/StaticAnalyzer/Checkers/RetainCountChecker/RetainCountDiagnostics.cpp new file mode 100644 index 00000000000..4ba09519b97 --- /dev/null +++ b/clang/lib/StaticAnalyzer/Checkers/RetainCountChecker/RetainCountDiagnostics.cpp @@ -0,0 +1,568 @@ +// RetainCountDiagnostics.cpp - Checks for leaks and other issues -*- 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 diagnostics for RetainCountChecker, which implements +// a reference count checker for Core Foundation and Cocoa on (Mac OS X). +// +//===----------------------------------------------------------------------===// + +#include "RetainCountDiagnostics.h" +#include "RetainCountChecker.h" + +using namespace clang; +using namespace ento; +using namespace retaincountchecker; + +static bool isNumericLiteralExpression(const Expr *E) { + // FIXME: This set of cases was copied from SemaExprObjC. + return isa<IntegerLiteral>(E) || + isa<CharacterLiteral>(E) || + isa<FloatingLiteral>(E) || + isa<ObjCBoolLiteralExpr>(E) || + isa<CXXBoolLiteralExpr>(E); +} + +std::shared_ptr<PathDiagnosticPiece> +CFRefReportVisitor::VisitNode(const ExplodedNode *N, const ExplodedNode *PrevN, + BugReporterContext &BRC, BugReport &BR) { + // FIXME: We will eventually need to handle non-statement-based events + // (__attribute__((cleanup))). + if (!N->getLocation().getAs<StmtPoint>()) + return nullptr; + + // Check if the type state has changed. + ProgramStateRef PrevSt = PrevN->getState(); + ProgramStateRef CurrSt = N->getState(); + const LocationContext *LCtx = N->getLocationContext(); + + const RefVal* CurrT = getRefBinding(CurrSt, Sym); + if (!CurrT) return nullptr; + + const RefVal &CurrV = *CurrT; + const RefVal *PrevT = getRefBinding(PrevSt, Sym); + + // Create a string buffer to constain all the useful things we want + // to tell the user. + std::string sbuf; + llvm::raw_string_ostream os(sbuf); + + // This is the allocation site since the previous node had no bindings + // for this symbol. + if (!PrevT) { + const Stmt *S = N->getLocation().castAs<StmtPoint>().getStmt(); + + if (isa<ObjCIvarRefExpr>(S) && + isSynthesizedAccessor(LCtx->getStackFrame())) { + S = LCtx->getStackFrame()->getCallSite(); + } + + if (isa<ObjCArrayLiteral>(S)) { + os << "NSArray literal is an object with a +0 retain count"; + } + else if (isa<ObjCDictionaryLiteral>(S)) { + os << "NSDictionary literal is an object with a +0 retain count"; + } + else if (const ObjCBoxedExpr *BL = dyn_cast<ObjCBoxedExpr>(S)) { + if (isNumericLiteralExpression(BL->getSubExpr())) + os << "NSNumber literal is an object with a +0 retain count"; + else { + const ObjCInterfaceDecl *BoxClass = nullptr; + if (const ObjCMethodDecl *Method = BL->getBoxingMethod()) + BoxClass = Method->getClassInterface(); + + // We should always be able to find the boxing class interface, + // but consider this future-proofing. + if (BoxClass) + os << *BoxClass << " b"; + else + os << "B"; + + os << "oxed expression produces an object with a +0 retain count"; + } + } + else if (isa<ObjCIvarRefExpr>(S)) { + os << "Object loaded from instance variable"; + } + else { + if (const CallExpr *CE = dyn_cast<CallExpr>(S)) { + // Get the name of the callee (if it is available). + SVal X = CurrSt->getSValAsScalarOrLoc(CE->getCallee(), LCtx); + if (const FunctionDecl *FD = X.getAsFunctionDecl()) + os << "Call to function '" << *FD << '\''; + else + os << "function call"; + } + else { + assert(isa<ObjCMessageExpr>(S)); + CallEventManager &Mgr = CurrSt->getStateManager().getCallEventManager(); + CallEventRef<ObjCMethodCall> Call + = Mgr.getObjCMethodCall(cast<ObjCMessageExpr>(S), CurrSt, LCtx); + + switch (Call->getMessageKind()) { + case OCM_Message: + os << "Method"; + break; + case OCM_PropertyAccess: + os << "Property"; + break; + case OCM_Subscript: + os << "Subscript"; + break; + } + } + + if (CurrV.getObjKind() == RetEffect::CF) { + os << " returns a Core Foundation object of type " + << Sym->getType().getAsString() << " with a "; + } else if (CurrV.getObjKind() == RetEffect::Generalized) { + os << " returns an object of type " << Sym->getType().getAsString() + << " with a "; + } else { + assert (CurrV.getObjKind() == RetEffect::ObjC); + QualType T = Sym->getType(); + if (!isa<ObjCObjectPointerType>(T)) { + os << " returns an Objective-C object with a "; + } else { + const ObjCObjectPointerType *PT = cast<ObjCObjectPointerType>(T); + os << " returns an instance of " + << PT->getPointeeType().getAsString() << " with a "; + } + } + + if (CurrV.isOwned()) { + os << "+1 retain count"; + } else { + assert (CurrV.isNotOwned()); + os << "+0 retain count"; + } + } + + PathDiagnosticLocation Pos(S, BRC.getSourceManager(), + N->getLocationContext()); + return std::make_shared<PathDiagnosticEventPiece>(Pos, os.str()); + } + + // Gather up the effects that were performed on the object at this + // program point + SmallVector<ArgEffect, 2> AEffects; + + const ExplodedNode *OrigNode = BRC.getNodeResolver().getOriginalNode(N); + if (const RetainSummary *Summ = SummaryLog.lookup(OrigNode)) { + // We only have summaries attached to nodes after evaluating CallExpr and + // ObjCMessageExprs. + const Stmt *S = N->getLocation().castAs<StmtPoint>().getStmt(); + + if (const CallExpr *CE = dyn_cast<CallExpr>(S)) { + // Iterate through the parameter expressions and see if the symbol + // was ever passed as an argument. + unsigned i = 0; + + for (CallExpr::const_arg_iterator AI=CE->arg_begin(), AE=CE->arg_end(); + AI!=AE; ++AI, ++i) { + + // Retrieve the value of the argument. Is it the symbol + // we are interested in? + if (CurrSt->getSValAsScalarOrLoc(*AI, LCtx).getAsLocSymbol() != Sym) + continue; + + // We have an argument. Get the effect! + AEffects.push_back(Summ->getArg(i)); + } + } else if (const ObjCMessageExpr *ME = dyn_cast<ObjCMessageExpr>(S)) { + if (const Expr *receiver = ME->getInstanceReceiver()) { + if (CurrSt->getSValAsScalarOrLoc(receiver, LCtx) + .getAsLocSymbol() == Sym) { + // The symbol we are tracking is the receiver. + AEffects.push_back(Summ->getReceiverEffect()); + } + } + } + } + + do { + // Get the previous type state. + RefVal PrevV = *PrevT; + + // Specially handle -dealloc. + if (std::find(AEffects.begin(), AEffects.end(), Dealloc) != + AEffects.end()) { + // Determine if the object's reference count was pushed to zero. + assert(!PrevV.hasSameState(CurrV) && "The state should have changed."); + // We may not have transitioned to 'release' if we hit an error. + // This case is handled elsewhere. + if (CurrV.getKind() == RefVal::Released) { + assert(CurrV.getCombinedCounts() == 0); + os << "Object released by directly sending the '-dealloc' message"; + break; + } + } + + // Determine if the typestate has changed. + if (!PrevV.hasSameState(CurrV)) + switch (CurrV.getKind()) { + case RefVal::Owned: + case RefVal::NotOwned: + if (PrevV.getCount() == CurrV.getCount()) { + // Did an autorelease message get sent? + if (PrevV.getAutoreleaseCount() == CurrV.getAutoreleaseCount()) + return nullptr; + + assert(PrevV.getAutoreleaseCount() < CurrV.getAutoreleaseCount()); + os << "Object autoreleased"; + break; + } + + if (PrevV.getCount() > CurrV.getCount()) + os << "Reference count decremented."; + else + os << "Reference count incremented."; + + if (unsigned Count = CurrV.getCount()) + os << " The object now has a +" << Count << " retain count."; + + break; + + case RefVal::Released: + if (CurrV.getIvarAccessHistory() == + RefVal::IvarAccessHistory::ReleasedAfterDirectAccess && + CurrV.getIvarAccessHistory() != PrevV.getIvarAccessHistory()) { + os << "Strong instance variable relinquished. "; + } + os << "Object released."; + break; + + case RefVal::ReturnedOwned: + // Autoreleases can be applied after marking a node ReturnedOwned. + if (CurrV.getAutoreleaseCount()) + return nullptr; + + os << "Object returned to caller as an owning reference (single " + "retain count transferred to caller)"; + break; + + case RefVal::ReturnedNotOwned: + os << "Object returned to caller with a +0 retain count"; + break; + + default: + return nullptr; + } + } while (0); + + if (os.str().empty()) + return nullptr; // We have nothing to say! + + const Stmt *S = N->getLocation().castAs<StmtPoint>().getStmt(); + PathDiagnosticLocation Pos(S, BRC.getSourceManager(), + N->getLocationContext()); + auto P = std::make_shared<PathDiagnosticEventPiece>(Pos, os.str()); + + // Add the range by scanning the children of the statement for any bindings + // to Sym. + for (const Stmt *Child : S->children()) + if (const Expr *Exp = dyn_cast_or_null<Expr>(Child)) + if (CurrSt->getSValAsScalarOrLoc(Exp, LCtx).getAsLocSymbol() == Sym) { + P->addRange(Exp->getSourceRange()); + break; + } + + return std::move(P); +} + +static Optional<std::string> describeRegion(const MemRegion *MR) { + if (const auto *VR = dyn_cast_or_null<VarRegion>(MR)) + return std::string(VR->getDecl()->getName()); + // Once we support more storage locations for bindings, + // this would need to be improved. + return None; +} + +namespace { +// Find the first node in the current function context that referred to the +// tracked symbol and the memory location that value was stored to. Note, the +// value is only reported if the allocation occurred in the same function as +// the leak. The function can also return a location context, which should be +// treated as interesting. +struct AllocationInfo { + const ExplodedNode* N; + const MemRegion *R; + const LocationContext *InterestingMethodContext; + AllocationInfo(const ExplodedNode *InN, + const MemRegion *InR, + const LocationContext *InInterestingMethodContext) : + N(InN), R(InR), InterestingMethodContext(InInterestingMethodContext) {} +}; +} // end anonymous namespace + +static AllocationInfo +GetAllocationSite(ProgramStateManager& StateMgr, const ExplodedNode *N, + SymbolRef Sym) { + const ExplodedNode *AllocationNode = N; + const ExplodedNode *AllocationNodeInCurrentOrParentContext = N; + const MemRegion *FirstBinding = nullptr; + const LocationContext *LeakContext = N->getLocationContext(); + + // The location context of the init method called on the leaked object, if + // available. + const LocationContext *InitMethodContext = nullptr; + + while (N) { + ProgramStateRef St = N->getState(); + const LocationContext *NContext = N->getLocationContext(); + + if (!getRefBinding(St, Sym)) + break; + + StoreManager::FindUniqueBinding FB(Sym); + StateMgr.iterBindings(St, FB); + + if (FB) { + const MemRegion *R = FB.getRegion(); + const VarRegion *VR = R->getBaseRegion()->getAs<VarRegion>(); + // Do not show local variables belonging to a function other than + // where the error is reported. + if (!VR || VR->getStackFrame() == LeakContext->getStackFrame()) + FirstBinding = R; + } + + // AllocationNode is the last node in which the symbol was tracked. + AllocationNode = N; + + // AllocationNodeInCurrentContext, is the last node in the current or + // parent context in which the symbol was tracked. + // + // Note that the allocation site might be in the parent conext. For example, + // the case where an allocation happens in a block that captures a reference + // to it and that reference is overwritten/dropped by another call to + // the block. + if (NContext == LeakContext || NContext->isParentOf(LeakContext)) + AllocationNodeInCurrentOrParentContext = N; + + // Find the last init that was called on the given symbol and store the + // init method's location context. + if (!InitMethodContext) + if (Optional<CallEnter> CEP = N->getLocation().getAs<CallEnter>()) { + const Stmt *CE = CEP->getCallExpr(); + if (const ObjCMessageExpr *ME = dyn_cast_or_null<ObjCMessageExpr>(CE)) { + const Stmt *RecExpr = ME->getInstanceReceiver(); + if (RecExpr) { + SVal RecV = St->getSVal(RecExpr, NContext); + if (ME->getMethodFamily() == OMF_init && RecV.getAsSymbol() == Sym) + InitMethodContext = CEP->getCalleeContext(); + } + } + } + + N = N->pred_empty() ? nullptr : *(N->pred_begin()); + } + + // If we are reporting a leak of the object that was allocated with alloc, + // mark its init method as interesting. + const LocationContext *InterestingMethodContext = nullptr; + if (InitMethodContext) { + const ProgramPoint AllocPP = AllocationNode->getLocation(); + if (Optional<StmtPoint> SP = AllocPP.getAs<StmtPoint>()) + if (const ObjCMessageExpr *ME = SP->getStmtAs<ObjCMessageExpr>()) + if (ME->getMethodFamily() == OMF_alloc) + InterestingMethodContext = InitMethodContext; + } + + // If allocation happened in a function different from the leak node context, + // do not report the binding. + assert(N && "Could not find allocation node"); + if (N->getLocationContext() != LeakContext) { + FirstBinding = nullptr; + } + + return AllocationInfo(AllocationNodeInCurrentOrParentContext, + FirstBinding, + InterestingMethodContext); +} + +std::shared_ptr<PathDiagnosticPiece> +CFRefReportVisitor::getEndPath(BugReporterContext &BRC, + const ExplodedNode *EndN, BugReport &BR) { + BR.markInteresting(Sym); + return BugReporterVisitor::getDefaultEndPath(BRC, EndN, BR); +} + +std::shared_ptr<PathDiagnosticPiece> +CFRefLeakReportVisitor::getEndPath(BugReporterContext &BRC, + const ExplodedNode *EndN, BugReport &BR) { + + // Tell the BugReporterContext to report cases when the tracked symbol is + // assigned to different variables, etc. + BR.markInteresting(Sym); + + // We are reporting 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. + AllocationInfo AllocI = + GetAllocationSite(BRC.getStateManager(), EndN, Sym); + + const MemRegion* FirstBinding = AllocI.R; + BR.markInteresting(AllocI.InterestingMethodContext); + + SourceManager& SM = BRC.getSourceManager(); + + // Compute an actual location for the leak. Sometimes a leak doesn't + // occur at an actual statement (e.g., transition between blocks; end + // of function) so we need to walk the graph and compute a real location. + const ExplodedNode *LeakN = EndN; + PathDiagnosticLocation L = PathDiagnosticLocation::createEndOfPath(LeakN, SM); + + std::string sbuf; + llvm::raw_string_ostream os(sbuf); + + os << "Object leaked: "; + + Optional<std::string> RegionDescription = describeRegion(FirstBinding); + if (RegionDescription) { + os << "object allocated and stored into '" << *RegionDescription << '\''; + } + else + os << "allocated object"; + + // Get the retain count. + const RefVal* RV = getRefBinding(EndN->getState(), Sym); + assert(RV); + + if (RV->getKind() == RefVal::ErrorLeakReturned) { + // FIXME: Per comments in rdar://6320065, "create" only applies to CF + // objects. Only "copy", "alloc", "retain" and "new" transfer ownership + // to the caller for NS objects. + const Decl *D = &EndN->getCodeDecl(); + + os << (isa<ObjCMethodDecl>(D) ? " is returned from a method " + : " is returned from a function "); + + if (D->hasAttr<CFReturnsNotRetainedAttr>()) + os << "that is annotated as CF_RETURNS_NOT_RETAINED"; + else if (D->hasAttr<NSReturnsNotRetainedAttr>()) + os << "that is annotated as NS_RETURNS_NOT_RETAINED"; + else { + if (const ObjCMethodDecl *MD = dyn_cast<ObjCMethodDecl>(D)) { + if (BRC.getASTContext().getLangOpts().ObjCAutoRefCount) { + os << "managed by Automatic Reference Counting"; + } else { + os << "whose name ('" << MD->getSelector().getAsString() + << "') does not start with " + "'copy', 'mutableCopy', 'alloc' or 'new'." + " This violates the naming convention rules" + " given in the Memory Management Guide for Cocoa"; + } + } + else { + const FunctionDecl *FD = cast<FunctionDecl>(D); + os << "whose name ('" << *FD + << "') does not contain 'Copy' or 'Create'. This violates the naming" + " convention rules given in the Memory Management Guide for Core" + " Foundation"; + } + } + } + else + os << " is not referenced later in this execution path and has a retain " + "count of +" << RV->getCount(); + + return std::make_shared<PathDiagnosticEventPiece>(L, os.str()); +} + +void CFRefLeakReport::deriveParamLocation(CheckerContext &Ctx, SymbolRef sym) { + const SourceManager& SMgr = Ctx.getSourceManager(); + + if (!sym->getOriginRegion()) + return; + + auto *Region = dyn_cast<DeclRegion>(sym->getOriginRegion()); + if (Region) { + const Decl *PDecl = Region->getDecl(); + if (PDecl && isa<ParmVarDecl>(PDecl)) { + PathDiagnosticLocation ParamLocation = PathDiagnosticLocation::create(PDecl, SMgr); + Location = ParamLocation; + UniqueingLocation = ParamLocation; + UniqueingDecl = Ctx.getLocationContext()->getDecl(); + } + } +} + +void CFRefLeakReport::deriveAllocLocation(CheckerContext &Ctx,SymbolRef sym) { + // Most bug reports are cached at the location where they occurred. + // With leaks, we want to unique them by the location where they were + // allocated, and only report a single path. To do this, we need to find + // the allocation site of a piece of tracked memory, which we do via a + // call to GetAllocationSite. This will walk the ExplodedGraph backwards. + // Note that this is *not* the trimmed graph; we are guaranteed, however, + // that all ancestor nodes that represent the allocation site have the + // same SourceLocation. + const ExplodedNode *AllocNode = nullptr; + + const SourceManager& SMgr = Ctx.getSourceManager(); + + AllocationInfo AllocI = + GetAllocationSite(Ctx.getStateManager(), getErrorNode(), sym); + + AllocNode = AllocI.N; + AllocBinding = AllocI.R; + markInteresting(AllocI.InterestingMethodContext); + + // Get the SourceLocation for the allocation site. + // FIXME: This will crash the analyzer if an allocation comes from an + // implicit call (ex: a destructor call). + // (Currently there are no such allocations in Cocoa, though.) + AllocStmt = PathDiagnosticLocation::getStmt(AllocNode); + + if (!AllocStmt) { + AllocBinding = nullptr; + return; + } + + PathDiagnosticLocation AllocLocation = + PathDiagnosticLocation::createBegin(AllocStmt, SMgr, + AllocNode->getLocationContext()); + Location = AllocLocation; + + // Set uniqieing info, which will be used for unique the bug reports. The + // leaks should be uniqued on the allocation site. + UniqueingLocation = AllocLocation; + UniqueingDecl = AllocNode->getLocationContext()->getDecl(); +} + +void CFRefLeakReport::createDescription(CheckerContext &Ctx, + bool IncludeAllocationLine) { + assert(Location.isValid() && UniqueingDecl && UniqueingLocation.isValid()); + Description.clear(); + llvm::raw_string_ostream os(Description); + os << "Potential leak of an object"; + + Optional<std::string> RegionDescription = describeRegion(AllocBinding); + if (RegionDescription) { + os << " stored into '" << *RegionDescription << '\''; + if (IncludeAllocationLine) { + FullSourceLoc SL(AllocStmt->getBeginLoc(), Ctx.getSourceManager()); + os << " (allocated on line " << SL.getSpellingLineNumber() << ")"; + } + } +} + +CFRefLeakReport::CFRefLeakReport(CFRefBug &D, const LangOptions &LOpts, + const SummaryLogTy &Log, + ExplodedNode *n, SymbolRef sym, + CheckerContext &Ctx, + bool IncludeAllocationLine) + : CFRefReport(D, LOpts, Log, n, sym, false) { + + deriveAllocLocation(Ctx, sym); + if (!AllocBinding) + deriveParamLocation(Ctx, sym); + + createDescription(Ctx, IncludeAllocationLine); + + addVisitor(llvm::make_unique<CFRefLeakReportVisitor>(sym, Log)); +} diff --git a/clang/lib/StaticAnalyzer/Checkers/RetainCountChecker/RetainCountDiagnostics.h b/clang/lib/StaticAnalyzer/Checkers/RetainCountChecker/RetainCountDiagnostics.h new file mode 100644 index 00000000000..cbdfe3a9166 --- /dev/null +++ b/clang/lib/StaticAnalyzer/Checkers/RetainCountChecker/RetainCountDiagnostics.h @@ -0,0 +1,198 @@ +//== RetainCountDiagnostics.h - Checks for leaks and other issues -*- 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 diagnostics for RetainCountChecker, which implements +// a reference count checker for Core Foundation and Cocoa on (Mac OS X). +// +//===----------------------------------------------------------------------===// + +#ifndef LLVM_CLANG_LIB_STATICANALYZER_CHECKERS_RETAINCOUNTCHECKER_DIAGNOSTICS_H +#define LLVM_CLANG_LIB_STATICANALYZER_CHECKERS_RETAINCOUNTCHECKER_DIAGNOSTICS_H + +#include "RetainCountSummaries.h" +#include "clang/StaticAnalyzer/Core/BugReporter/BugType.h" +#include "clang/StaticAnalyzer/Core/BugReporter/BugReporterVisitors.h" +#include "clang/StaticAnalyzer/Core/BugReporter/PathDiagnostic.h" + +namespace clang { +namespace ento { +namespace retaincountchecker { + +class CFRefBug : public BugType { +protected: + CFRefBug(const CheckerBase *checker, StringRef name) + : BugType(checker, name, categories::MemoryCoreFoundationObjectiveC) {} + +public: + + // FIXME: Eventually remove. + virtual const char *getDescription() const = 0; + + virtual bool isLeak() const { return false; } +}; + +class UseAfterRelease : public CFRefBug { +public: + UseAfterRelease(const CheckerBase *checker) + : CFRefBug(checker, "Use-after-release") {} + + const char *getDescription() const override { + return "Reference-counted object is used after it is released"; + } +}; + +class BadRelease : public CFRefBug { +public: + BadRelease(const CheckerBase *checker) : CFRefBug(checker, "Bad release") {} + + const char *getDescription() const override { + return "Incorrect decrement of the reference count of an object that is " + "not owned at this point by the caller"; + } +}; + +class DeallocNotOwned : public CFRefBug { +public: + DeallocNotOwned(const CheckerBase *checker) + : CFRefBug(checker, "-dealloc sent to non-exclusively owned object") {} + + const char *getDescription() const override { + return "-dealloc sent to object that may be referenced elsewhere"; + } +}; + +class OverAutorelease : public CFRefBug { +public: + OverAutorelease(const CheckerBase *checker) + : CFRefBug(checker, "Object autoreleased too many times") {} + + const char *getDescription() const override { + return "Object autoreleased too many times"; + } +}; + +class ReturnedNotOwnedForOwned : public CFRefBug { +public: + ReturnedNotOwnedForOwned(const CheckerBase *checker) + : CFRefBug(checker, "Method should return an owned object") {} + + const char *getDescription() const override { + return "Object with a +0 retain count returned to caller where a +1 " + "(owning) retain count is expected"; + } +}; + +class Leak : public CFRefBug { +public: + Leak(const CheckerBase *checker, StringRef name) : CFRefBug(checker, name) { + // Leaks should not be reported if they are post-dominated by a sink. + setSuppressOnSink(true); + } + + const char *getDescription() const override { return ""; } + + bool isLeak() const override { return true; } +}; + +typedef ::llvm::DenseMap<const ExplodedNode *, const RetainSummary *> + SummaryLogTy; + +/// Visitors. + +class CFRefReportVisitor : public BugReporterVisitor { +protected: + SymbolRef Sym; + const SummaryLogTy &SummaryLog; + +public: + CFRefReportVisitor(SymbolRef sym, const SummaryLogTy &log) + : Sym(sym), SummaryLog(log) {} + + void Profile(llvm::FoldingSetNodeID &ID) const override { + static int x = 0; + ID.AddPointer(&x); + ID.AddPointer(Sym); + } + + std::shared_ptr<PathDiagnosticPiece> VisitNode(const ExplodedNode *N, + const ExplodedNode *PrevN, + BugReporterContext &BRC, + BugReport &BR) override; + + std::shared_ptr<PathDiagnosticPiece> getEndPath(BugReporterContext &BRC, + const ExplodedNode *N, + BugReport &BR) override; +}; + +class CFRefLeakReportVisitor : public CFRefReportVisitor { +public: + CFRefLeakReportVisitor(SymbolRef sym, + const SummaryLogTy &log) + : CFRefReportVisitor(sym, log) {} + + std::shared_ptr<PathDiagnosticPiece> getEndPath(BugReporterContext &BRC, + const ExplodedNode *N, + BugReport &BR) override; +}; + +class CFRefReport : public BugReport { + +public: + CFRefReport(CFRefBug &D, const LangOptions &LOpts, + const SummaryLogTy &Log, ExplodedNode *n, SymbolRef sym, + bool registerVisitor = true) + : BugReport(D, D.getDescription(), n) { + if (registerVisitor) + addVisitor(llvm::make_unique<CFRefReportVisitor>(sym, Log)); + } + + CFRefReport(CFRefBug &D, const LangOptions &LOpts, + const SummaryLogTy &Log, ExplodedNode *n, SymbolRef sym, + StringRef endText) + : BugReport(D, D.getDescription(), endText, n) { + addVisitor(llvm::make_unique<CFRefReportVisitor>(sym, Log)); + } + + llvm::iterator_range<ranges_iterator> getRanges() override { + const CFRefBug& BugTy = static_cast<CFRefBug&>(getBugType()); + if (!BugTy.isLeak()) + return BugReport::getRanges(); + return llvm::make_range(ranges_iterator(), ranges_iterator()); + } +}; + +class CFRefLeakReport : public CFRefReport { + const MemRegion* AllocBinding; + const Stmt *AllocStmt; + + // Finds the function declaration where a leak warning for the parameter + // 'sym' should be raised. + void deriveParamLocation(CheckerContext &Ctx, SymbolRef sym); + // Finds the location where a leak warning for 'sym' should be raised. + void deriveAllocLocation(CheckerContext &Ctx, SymbolRef sym); + // Produces description of a leak warning which is printed on the console. + void createDescription(CheckerContext &Ctx, bool IncludeAllocationLine); + +public: + CFRefLeakReport(CFRefBug &D, const LangOptions &LOpts, + const SummaryLogTy &Log, ExplodedNode *n, SymbolRef sym, + CheckerContext &Ctx, + bool IncludeAllocationLine); + + PathDiagnosticLocation getLocation(const SourceManager &SM) const override { + assert(Location.isValid()); + return Location; + } +}; + +} // end namespace retaincountchecker +} // end namespace ento +} // end namespace clang + +#endif diff --git a/clang/lib/StaticAnalyzer/Checkers/RetainCountChecker/RetainCountSummaries.cpp b/clang/lib/StaticAnalyzer/Checkers/RetainCountChecker/RetainCountSummaries.cpp new file mode 100644 index 00000000000..13de30a200a --- /dev/null +++ b/clang/lib/StaticAnalyzer/Checkers/RetainCountChecker/RetainCountSummaries.cpp @@ -0,0 +1,819 @@ +//== RetainCountSummaries.cpp - Checks for leaks and other issues -*- 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 summaries implementation for RetainCountChecker, which +// implements a reference count checker for Core Foundation and Cocoa +// on (Mac OS X). +// +//===----------------------------------------------------------------------===// + +#include "RetainCountSummaries.h" +#include "RetainCountChecker.h" + +#include "clang/Analysis/DomainSpecific/CocoaConventions.h" +#include "clang/AST/Attr.h" +#include "clang/AST/DeclCXX.h" +#include "clang/AST/DeclObjC.h" +#include "clang/AST/ParentMap.h" + +using namespace objc_retain; +using namespace clang; +using namespace ento; +using namespace retaincountchecker; + +ArgEffects RetainSummaryManager::getArgEffects() { + ArgEffects AE = ScratchArgs; + ScratchArgs = AF.getEmptyMap(); + return AE; +} + +const RetainSummary * +RetainSummaryManager::getPersistentSummary(const RetainSummary &OldSumm) { + // Unique "simple" summaries -- those without ArgEffects. + if (OldSumm.isSimple()) { + ::llvm::FoldingSetNodeID ID; + OldSumm.Profile(ID); + + void *Pos; + CachedSummaryNode *N = SimpleSummaries.FindNodeOrInsertPos(ID, Pos); + + if (!N) { + N = (CachedSummaryNode *) BPAlloc.Allocate<CachedSummaryNode>(); + new (N) CachedSummaryNode(OldSumm); + SimpleSummaries.InsertNode(N, Pos); + } + + return &N->getValue(); + } + + RetainSummary *Summ = (RetainSummary *) BPAlloc.Allocate<RetainSummary>(); + new (Summ) RetainSummary(OldSumm); + return Summ; +} + +const RetainSummary * +RetainSummaryManager::getFunctionSummary(const FunctionDecl *FD) { + // If we don't know what function we're calling, use our default summary. + if (!FD) + return getDefaultSummary(); + + // 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 RetainSummary *S = nullptr; + bool AllowAnnotations = true; + + do { + // We generate "stop" summaries for implicitly defined functions. + if (FD->isImplicit()) { + S = getPersistentStopSummary(); + break; + } + + // [PR 3337] Use 'getAs<FunctionType>' to strip away any typedefs on the + // function's type. + const FunctionType* FT = FD->getType()->getAs<FunctionType>(); + const IdentifierInfo *II = FD->getIdentifier(); + if (!II) + break; + + StringRef FName = II->getName(); + + // Strip away preceding '_'. Doing this here will effect all the checks + // down below. + FName = FName.substr(FName.find_first_not_of('_')); + + // Inspect the result type. + QualType RetTy = FT->getReturnType(); + std::string RetTyName = RetTy.getAsString(); + + // FIXME: This should all be refactored into a chain of "summary lookup" + // filters. + assert(ScratchArgs.isEmpty()); + + if (FName == "pthread_create" || FName == "pthread_setspecific") { + // Part of: <rdar://problem/7299394> and <rdar://problem/11282706>. + // This will be addressed better with IPA. + S = getPersistentStopSummary(); + } else if (FName == "CFPlugInInstanceCreate") { + S = getPersistentSummary(RetEffect::MakeNoRet()); + } else if (FName == "IORegistryEntrySearchCFProperty" + || (RetTyName == "CFMutableDictionaryRef" && ( + FName == "IOBSDNameMatching" || + FName == "IOServiceMatching" || + FName == "IOServiceNameMatching" || + FName == "IORegistryEntryIDMatching" || + FName == "IOOpenFirmwarePathMatching" + ))) { + // Part of <rdar://problem/6961230>. (IOKit) + // This should be addressed using a API table. + S = getPersistentSummary(RetEffect::MakeOwned(RetEffect::CF), + DoNothing, DoNothing); + } else if (FName == "IOServiceGetMatchingService" || + FName == "IOServiceGetMatchingServices") { + // FIXES: <rdar://problem/6326900> + // This should be addressed using a API table. This strcmp is also + // a little gross, but there is no need to super optimize here. + ScratchArgs = AF.add(ScratchArgs, 1, DecRef); + S = getPersistentSummary(RetEffect::MakeNoRet(), DoNothing, DoNothing); + } else if (FName == "IOServiceAddNotification" || + FName == "IOServiceAddMatchingNotification") { + // Part of <rdar://problem/6961230>. (IOKit) + // This should be addressed using a API table. + ScratchArgs = AF.add(ScratchArgs, 2, DecRef); + S = getPersistentSummary(RetEffect::MakeNoRet(), DoNothing, DoNothing); + } else if (FName == "CVPixelBufferCreateWithBytes") { + // FIXES: <rdar://problem/7283567> + // Eventually this can be improved by recognizing that the pixel + // buffer passed to CVPixelBufferCreateWithBytes is released via + // a callback and doing full IPA to make sure this is done correctly. + // FIXME: This function has an out parameter that returns an + // allocated object. + ScratchArgs = AF.add(ScratchArgs, 7, StopTracking); + S = getPersistentSummary(RetEffect::MakeNoRet(), DoNothing, DoNothing); + } else if (FName == "CGBitmapContextCreateWithData") { + // FIXES: <rdar://problem/7358899> + // Eventually this can be improved by recognizing that 'releaseInfo' + // passed to CGBitmapContextCreateWithData is released via + // a callback and doing full IPA to make sure this is done correctly. + ScratchArgs = AF.add(ScratchArgs, 8, StopTracking); + S = getPersistentSummary(RetEffect::MakeOwned(RetEffect::CF), + DoNothing, DoNothing); + } else if (FName == "CVPixelBufferCreateWithPlanarBytes") { + // FIXES: <rdar://problem/7283567> + // Eventually this can be improved by recognizing that the pixel + // buffer passed to CVPixelBufferCreateWithPlanarBytes is released + // via a callback and doing full IPA to make sure this is done + // correctly. + ScratchArgs = AF.add(ScratchArgs, 12, StopTracking); + S = getPersistentSummary(RetEffect::MakeNoRet(), DoNothing, DoNothing); + } else if (FName == "VTCompressionSessionEncodeFrame") { + // The context argument passed to VTCompressionSessionEncodeFrame() + // is passed to the callback specified when creating the session + // (e.g. with VTCompressionSessionCreate()) which can release it. + // To account for this possibility, conservatively stop tracking + // the context. + ScratchArgs = AF.add(ScratchArgs, 5, StopTracking); + S = getPersistentSummary(RetEffect::MakeNoRet(), DoNothing, DoNothing); + } else if (FName == "dispatch_set_context" || + FName == "xpc_connection_set_context") { + // <rdar://problem/11059275> - The analyzer currently doesn't have + // a good way to reason about the finalizer function for libdispatch. + // If we pass a context object that is memory managed, stop tracking it. + // <rdar://problem/13783514> - Same problem, but for XPC. + // FIXME: this hack should possibly go away once we can handle + // libdispatch and XPC finalizers. + ScratchArgs = AF.add(ScratchArgs, 1, StopTracking); + S = getPersistentSummary(RetEffect::MakeNoRet(), DoNothing, DoNothing); + } else if (FName.startswith("NSLog")) { + S = getDoNothingSummary(); + } else if (FName.startswith("NS") && + (FName.find("Insert") != StringRef::npos)) { + // Whitelist NSXXInsertXX, for example NSMapInsertIfAbsent, since they can + // be deallocated by NSMapRemove. (radar://11152419) + ScratchArgs = AF.add(ScratchArgs, 1, StopTracking); + ScratchArgs = AF.add(ScratchArgs, 2, StopTracking); + S = getPersistentSummary(RetEffect::MakeNoRet(), DoNothing, DoNothing); + } + + // Did we get a summary? + if (S) + break; + + if (RetTy->isPointerType()) { + // For CoreFoundation ('CF') types. + if (cocoa::isRefType(RetTy, "CF", FName)) { + if (RetainSummary::isRetain(FD, FName)) { + S = getUnarySummary(FT, cfretain); + // CFRetain isn't supposed to be annotated. However, this may as well + // be a user-made "safe" CFRetain function that is incorrectly + // annotated as cf_returns_retained due to lack of better options. + // We want to ignore such annotation. + AllowAnnotations = false; + } else if (RetainSummary::isAutorelease(FD, FName)) { + S = getUnarySummary(FT, cfautorelease); + // The headers use cf_consumed, but we can fully model CFAutorelease + // ourselves. + AllowAnnotations = false; + } else { + S = getCFCreateGetRuleSummary(FD); + } + + break; + } + + // For CoreGraphics ('CG') and CoreVideo ('CV') types. + if (cocoa::isRefType(RetTy, "CG", FName) || + cocoa::isRefType(RetTy, "CV", FName)) { + if (RetainSummary::isRetain(FD, FName)) + S = getUnarySummary(FT, cfretain); + else + S = getCFCreateGetRuleSummary(FD); + + break; + } + + // For all other CF-style types, use the Create/Get + // rule for summaries but don't support Retain functions + // with framework-specific prefixes. + if (coreFoundation::isCFObjectRef(RetTy)) { + S = getCFCreateGetRuleSummary(FD); + break; + } + + if (FD->hasAttr<CFAuditedTransferAttr>()) { + S = getCFCreateGetRuleSummary(FD); + break; + } + + break; + } + + // Check for release functions, the only kind of functions that we care + // about that don't return a pointer type. + if (FName.size() >= 2 && + FName[0] == 'C' && (FName[1] == 'F' || FName[1] == 'G')) { + // Test for 'CGCF'. + FName = FName.substr(FName.startswith("CGCF") ? 4 : 2); + + if (RetainSummary::isRelease(FD, FName)) + S = getUnarySummary(FT, cfrelease); + else { + assert (ScratchArgs.isEmpty()); + // Remaining CoreFoundation and CoreGraphics functions. + // We use to assume that they all strictly followed the ownership idiom + // and that ownership cannot be transferred. While this is technically + // correct, many methods allow a tracked object to escape. For example: + // + // CFMutableDictionaryRef x = CFDictionaryCreateMutable(...); + // CFDictionaryAddValue(y, key, x); + // CFRelease(x); + // ... it is okay to use 'x' since 'y' has a reference to it + // + // We handle this and similar cases with the follow heuristic. If the + // function name contains "InsertValue", "SetValue", "AddValue", + // "AppendValue", or "SetAttribute", then we assume that arguments may + // "escape." This means that something else holds on to the object, + // allowing it be used even after its local retain count drops to 0. + ArgEffect E = (StrInStrNoCase(FName, "InsertValue") != StringRef::npos|| + StrInStrNoCase(FName, "AddValue") != StringRef::npos || + StrInStrNoCase(FName, "SetValue") != StringRef::npos || + StrInStrNoCase(FName, "AppendValue") != StringRef::npos|| + StrInStrNoCase(FName, "SetAttribute") != StringRef::npos) + ? MayEscape : DoNothing; + + S = getPersistentSummary(RetEffect::MakeNoRet(), DoNothing, E); + } + } + } + while (0); + + // If we got all the way here without any luck, use a default summary. + if (!S) + S = getDefaultSummary(); + + // Annotations override defaults. + if (AllowAnnotations) + updateSummaryFromAnnotations(S, FD); + + FuncSummaries[FD] = S; + return S; +} + +//===----------------------------------------------------------------------===// +// Summary creation for functions (largely uses of Core Foundation). +//===----------------------------------------------------------------------===// + + +static ArgEffect getStopTrackingHardEquivalent(ArgEffect E) { + switch (E) { + case DoNothing: + case Autorelease: + case DecRefBridgedTransferred: + case IncRef: + case IncRefMsg: + case UnretainedOutParameter: + case RetainedOutParameter: + case MayEscape: + case StopTracking: + case StopTrackingHard: + return StopTrackingHard; + case DecRef: + case DecRefAndStopTrackingHard: + return DecRefAndStopTrackingHard; + case DecRefMsg: + case DecRefMsgAndStopTrackingHard: + return DecRefMsgAndStopTrackingHard; + case Dealloc: + return Dealloc; + } + + llvm_unreachable("Unknown ArgEffect kind"); +} + +void RetainSummaryManager::updateSummaryForCall(const RetainSummary *&S, + const CallEvent &Call) { + if (Call.hasNonZeroCallbackArg()) { + ArgEffect RecEffect = + getStopTrackingHardEquivalent(S->getReceiverEffect()); + ArgEffect DefEffect = + getStopTrackingHardEquivalent(S->getDefaultArgEffect()); + + ArgEffects CustomArgEffects = S->getArgEffects(); + for (ArgEffects::iterator I = CustomArgEffects.begin(), + E = CustomArgEffects.end(); + I != E; ++I) { + ArgEffect Translated = getStopTrackingHardEquivalent(I->second); + if (Translated != DefEffect) + ScratchArgs = AF.add(ScratchArgs, I->first, Translated); + } + + RetEffect RE = RetEffect::MakeNoRetHard(); + + // Special cases where the callback argument CANNOT free the return value. + // This can generally only happen if we know that the callback will only be + // called when the return value is already being deallocated. + if (const SimpleFunctionCall *FC = dyn_cast<SimpleFunctionCall>(&Call)) { + if (IdentifierInfo *Name = FC->getDecl()->getIdentifier()) { + // When the CGBitmapContext is deallocated, the callback here will free + // the associated data buffer. + // The callback in dispatch_data_create frees the buffer, but not + // the data object. + if (Name->isStr("CGBitmapContextCreateWithData") || + Name->isStr("dispatch_data_create")) + RE = S->getRetEffect(); + } + } + + S = getPersistentSummary(RE, RecEffect, DefEffect); + } + + // Special case '[super init];' and '[self init];' + // + // Even though calling '[super init]' without assigning the result to self + // and checking if the parent returns 'nil' is a bad pattern, it is common. + // Additionally, our Self Init checker already warns about it. To avoid + // overwhelming the user with messages from both checkers, we model the case + // of '[super init]' in cases when it is not consumed by another expression + // as if the call preserves the value of 'self'; essentially, assuming it can + // never fail and return 'nil'. + // Note, we don't want to just stop tracking the value since we want the + // RetainCount checker to report leaks and use-after-free if SelfInit checker + // is turned off. + if (const ObjCMethodCall *MC = dyn_cast<ObjCMethodCall>(&Call)) { + if (MC->getMethodFamily() == OMF_init && MC->isReceiverSelfOrSuper()) { + + // Check if the message is not consumed, we know it will not be used in + // an assignment, ex: "self = [super init]". + const Expr *ME = MC->getOriginExpr(); + const LocationContext *LCtx = MC->getLocationContext(); + ParentMap &PM = LCtx->getAnalysisDeclContext()->getParentMap(); + if (!PM.isConsumedExpr(ME)) { + RetainSummaryTemplate ModifiableSummaryTemplate(S, *this); + ModifiableSummaryTemplate->setReceiverEffect(DoNothing); + ModifiableSummaryTemplate->setRetEffect(RetEffect::MakeNoRet()); + } + } + } +} + +const RetainSummary * +RetainSummaryManager::getSummary(const CallEvent &Call, + ProgramStateRef State) { + const RetainSummary *Summ; + switch (Call.getKind()) { + case CE_Function: + Summ = getFunctionSummary(cast<SimpleFunctionCall>(Call).getDecl()); + break; + case CE_CXXMember: + case CE_CXXMemberOperator: + case CE_Block: + case CE_CXXConstructor: + case CE_CXXDestructor: + case CE_CXXAllocator: + // FIXME: These calls are currently unsupported. + return getPersistentStopSummary(); + case CE_ObjCMessage: { + const ObjCMethodCall &Msg = cast<ObjCMethodCall>(Call); + if (Msg.isInstanceMessage()) + Summ = getInstanceMethodSummary(Msg, State); + else + Summ = getClassMethodSummary(Msg); + break; + } + } + + updateSummaryForCall(Summ, Call); + + assert(Summ && "Unknown call type?"); + return Summ; +} + + +const RetainSummary * +RetainSummaryManager::getCFCreateGetRuleSummary(const FunctionDecl *FD) { + if (coreFoundation::followsCreateRule(FD)) + return getCFSummaryCreateRule(FD); + + return getCFSummaryGetRule(FD); +} + +const RetainSummary * +RetainSummaryManager::getUnarySummary(const FunctionType* FT, + UnaryFuncKind func) { + + // Sanity check that this is *really* a unary function. This can + // happen if people do weird things. + const FunctionProtoType* FTP = dyn_cast<FunctionProtoType>(FT); + if (!FTP || FTP->getNumParams() != 1) + return getPersistentStopSummary(); + + assert (ScratchArgs.isEmpty()); + + ArgEffect Effect; + switch (func) { + case cfretain: Effect = IncRef; break; + case cfrelease: Effect = DecRef; break; + case cfautorelease: Effect = Autorelease; break; + } + + ScratchArgs = AF.add(ScratchArgs, 0, Effect); + return getPersistentSummary(RetEffect::MakeNoRet(), DoNothing, DoNothing); +} + +const RetainSummary * +RetainSummaryManager::getCFSummaryCreateRule(const FunctionDecl *FD) { + assert (ScratchArgs.isEmpty()); + + return getPersistentSummary(RetEffect::MakeOwned(RetEffect::CF)); +} + +const RetainSummary * +RetainSummaryManager::getCFSummaryGetRule(const FunctionDecl *FD) { + assert (ScratchArgs.isEmpty()); + return getPersistentSummary(RetEffect::MakeNotOwned(RetEffect::CF), + DoNothing, DoNothing); +} + + + + +//===----------------------------------------------------------------------===// +// Summary creation for Selectors. +//===----------------------------------------------------------------------===// + +Optional<RetEffect> +RetainSummaryManager::getRetEffectFromAnnotations(QualType RetTy, + const Decl *D) { + if (cocoa::isCocoaObjectRef(RetTy)) { + if (D->hasAttr<NSReturnsRetainedAttr>()) + return ObjCAllocRetE; + + if (D->hasAttr<NSReturnsNotRetainedAttr>() || + D->hasAttr<NSReturnsAutoreleasedAttr>()) + return RetEffect::MakeNotOwned(RetEffect::ObjC); + + } else if (!RetTy->isPointerType()) { + return None; + } + + if (D->hasAttr<CFReturnsRetainedAttr>()) + return RetEffect::MakeOwned(RetEffect::CF); + else if (RetainSummary::hasRCAnnotation(D, "rc_ownership_returns_retained")) + return RetEffect::MakeOwned(RetEffect::Generalized); + + if (D->hasAttr<CFReturnsNotRetainedAttr>()) + return RetEffect::MakeNotOwned(RetEffect::CF); + + return None; +} + +void +RetainSummaryManager::updateSummaryFromAnnotations(const RetainSummary *&Summ, + const FunctionDecl *FD) { + if (!FD) + return; + + assert(Summ && "Must have a summary to add annotations to."); + RetainSummaryTemplate Template(Summ, *this); + + // Effects on the parameters. + unsigned parm_idx = 0; + for (FunctionDecl::param_const_iterator pi = FD->param_begin(), + pe = FD->param_end(); pi != pe; ++pi, ++parm_idx) { + const ParmVarDecl *pd = *pi; + if (pd->hasAttr<NSConsumedAttr>()) + Template->addArg(AF, parm_idx, DecRefMsg); + else if (pd->hasAttr<CFConsumedAttr>() || + RetainSummary::hasRCAnnotation(pd, "rc_ownership_consumed")) + Template->addArg(AF, parm_idx, DecRef); + else if (pd->hasAttr<CFReturnsRetainedAttr>() || + RetainSummary::hasRCAnnotation(pd, "rc_ownership_returns_retained")) { + QualType PointeeTy = pd->getType()->getPointeeType(); + if (!PointeeTy.isNull()) + if (coreFoundation::isCFObjectRef(PointeeTy)) + Template->addArg(AF, parm_idx, RetainedOutParameter); + } else if (pd->hasAttr<CFReturnsNotRetainedAttr>()) { + QualType PointeeTy = pd->getType()->getPointeeType(); + if (!PointeeTy.isNull()) + if (coreFoundation::isCFObjectRef(PointeeTy)) + Template->addArg(AF, parm_idx, UnretainedOutParameter); + } + } + + QualType RetTy = FD->getReturnType(); + if (Optional<RetEffect> RetE = getRetEffectFromAnnotations(RetTy, FD)) + Template->setRetEffect(*RetE); +} + +void +RetainSummaryManager::updateSummaryFromAnnotations(const RetainSummary *&Summ, + const ObjCMethodDecl *MD) { + if (!MD) + return; + + assert(Summ && "Must have a valid summary to add annotations to"); + RetainSummaryTemplate Template(Summ, *this); + + // Effects on the receiver. + if (MD->hasAttr<NSConsumesSelfAttr>()) + Template->setReceiverEffect(DecRefMsg); + + // Effects on the parameters. + unsigned parm_idx = 0; + for (ObjCMethodDecl::param_const_iterator + pi=MD->param_begin(), pe=MD->param_end(); + pi != pe; ++pi, ++parm_idx) { + const ParmVarDecl *pd = *pi; + if (pd->hasAttr<NSConsumedAttr>()) + Template->addArg(AF, parm_idx, DecRefMsg); + else if (pd->hasAttr<CFConsumedAttr>()) { + Template->addArg(AF, parm_idx, DecRef); + } else if (pd->hasAttr<CFReturnsRetainedAttr>()) { + QualType PointeeTy = pd->getType()->getPointeeType(); + if (!PointeeTy.isNull()) + if (coreFoundation::isCFObjectRef(PointeeTy)) + Template->addArg(AF, parm_idx, RetainedOutParameter); + } else if (pd->hasAttr<CFReturnsNotRetainedAttr>()) { + QualType PointeeTy = pd->getType()->getPointeeType(); + if (!PointeeTy.isNull()) + if (coreFoundation::isCFObjectRef(PointeeTy)) + Template->addArg(AF, parm_idx, UnretainedOutParameter); + } + } + + QualType RetTy = MD->getReturnType(); + if (Optional<RetEffect> RetE = getRetEffectFromAnnotations(RetTy, MD)) + Template->setRetEffect(*RetE); +} + +const RetainSummary * +RetainSummaryManager::getStandardMethodSummary(const ObjCMethodDecl *MD, + Selector S, QualType RetTy) { + // Any special effects? + ArgEffect ReceiverEff = DoNothing; + RetEffect ResultEff = RetEffect::MakeNoRet(); + + // Check the method family, and apply any default annotations. + switch (MD ? MD->getMethodFamily() : S.getMethodFamily()) { + case OMF_None: + case OMF_initialize: + case OMF_performSelector: + // Assume all Objective-C methods follow Cocoa Memory Management rules. + // FIXME: Does the non-threaded performSelector family really belong here? + // The selector could be, say, @selector(copy). + if (cocoa::isCocoaObjectRef(RetTy)) + ResultEff = RetEffect::MakeNotOwned(RetEffect::ObjC); + else if (coreFoundation::isCFObjectRef(RetTy)) { + // ObjCMethodDecl currently doesn't consider CF objects as valid return + // values for alloc, new, copy, or mutableCopy, so we have to + // double-check with the selector. This is ugly, but there aren't that + // many Objective-C methods that return CF objects, right? + if (MD) { + switch (S.getMethodFamily()) { + case OMF_alloc: + case OMF_new: + case OMF_copy: + case OMF_mutableCopy: + ResultEff = RetEffect::MakeOwned(RetEffect::CF); + break; + default: + ResultEff = RetEffect::MakeNotOwned(RetEffect::CF); + break; + } + } else { + ResultEff = RetEffect::MakeNotOwned(RetEffect::CF); + } + } + break; + case OMF_init: + ResultEff = ObjCInitRetE; + ReceiverEff = DecRefMsg; + break; + case OMF_alloc: + case OMF_new: + case OMF_copy: + case OMF_mutableCopy: + if (cocoa::isCocoaObjectRef(RetTy)) + ResultEff = ObjCAllocRetE; + else if (coreFoundation::isCFObjectRef(RetTy)) + ResultEff = RetEffect::MakeOwned(RetEffect::CF); + break; + case OMF_autorelease: + ReceiverEff = Autorelease; + break; + case OMF_retain: + ReceiverEff = IncRefMsg; + break; + case OMF_release: + ReceiverEff = DecRefMsg; + break; + case OMF_dealloc: + ReceiverEff = Dealloc; + break; + case OMF_self: + // -self is handled specially by the ExprEngine to propagate the receiver. + break; + case OMF_retainCount: + case OMF_finalize: + // These methods don't return objects. + break; + } + + // If one of the arguments in the selector has the keyword 'delegate' we + // should stop tracking the reference count for the receiver. This is + // because the reference count is quite possibly handled by a delegate + // method. + if (S.isKeywordSelector()) { + for (unsigned i = 0, e = S.getNumArgs(); i != e; ++i) { + StringRef Slot = S.getNameForSlot(i); + if (Slot.substr(Slot.size() - 8).equals_lower("delegate")) { + if (ResultEff == ObjCInitRetE) + ResultEff = RetEffect::MakeNoRetHard(); + else + ReceiverEff = StopTrackingHard; + } + } + } + + if (ScratchArgs.isEmpty() && ReceiverEff == DoNothing && + ResultEff.getKind() == RetEffect::NoRet) + return getDefaultSummary(); + + return getPersistentSummary(ResultEff, ReceiverEff, MayEscape); +} + +const RetainSummary * +RetainSummaryManager::getInstanceMethodSummary(const ObjCMethodCall &Msg, + ProgramStateRef State) { + const ObjCInterfaceDecl *ReceiverClass = nullptr; + + // We do better tracking of the type of the object than the core ExprEngine. + // See if we have its type in our private state. + // FIXME: Eventually replace the use of state->get<RefBindings> with + // a generic API for reasoning about the Objective-C types of symbolic + // objects. + SVal ReceiverV = Msg.getReceiverSVal(); + if (SymbolRef Sym = ReceiverV.getAsLocSymbol()) + if (const RefVal *T = getRefBinding(State, Sym)) + if (const ObjCObjectPointerType *PT = + T->getType()->getAs<ObjCObjectPointerType>()) + ReceiverClass = PT->getInterfaceDecl(); + + // If we don't know what kind of object this is, fall back to its static type. + if (!ReceiverClass) + ReceiverClass = Msg.getReceiverInterface(); + + // FIXME: The receiver could be a reference to a class, meaning that + // we should use the class method. + // id x = [NSObject class]; + // [x performSelector:... withObject:... afterDelay:...]; + Selector S = Msg.getSelector(); + const ObjCMethodDecl *Method = Msg.getDecl(); + if (!Method && ReceiverClass) + Method = ReceiverClass->getInstanceMethod(S); + + return getMethodSummary(S, ReceiverClass, Method, Msg.getResultType(), + ObjCMethodSummaries); +} + +const RetainSummary * +RetainSummaryManager::getMethodSummary(Selector S, const ObjCInterfaceDecl *ID, + const ObjCMethodDecl *MD, QualType RetTy, + ObjCMethodSummariesTy &CachedSummaries) { + + // Look up a summary in our summary cache. + const RetainSummary *Summ = CachedSummaries.find(ID, S); + + if (!Summ) { + Summ = getStandardMethodSummary(MD, S, RetTy); + + // Annotations override defaults. + updateSummaryFromAnnotations(Summ, MD); + + // Memoize the summary. + CachedSummaries[ObjCSummaryKey(ID, S)] = Summ; + } + + return Summ; +} + +void RetainSummaryManager::InitializeClassMethodSummaries() { + assert(ScratchArgs.isEmpty()); + // Create the [NSAssertionHandler currentHander] summary. + addClassMethSummary("NSAssertionHandler", "currentHandler", + getPersistentSummary(RetEffect::MakeNotOwned(RetEffect::ObjC))); + + // Create the [NSAutoreleasePool addObject:] summary. + ScratchArgs = AF.add(ScratchArgs, 0, Autorelease); + addClassMethSummary("NSAutoreleasePool", "addObject", + getPersistentSummary(RetEffect::MakeNoRet(), + DoNothing, Autorelease)); +} + +void RetainSummaryManager::InitializeMethodSummaries() { + + assert (ScratchArgs.isEmpty()); + + // Create the "init" selector. It just acts as a pass-through for the + // receiver. + const RetainSummary *InitSumm = getPersistentSummary(ObjCInitRetE, DecRefMsg); + addNSObjectMethSummary(GetNullarySelector("init", Ctx), InitSumm); + + // awakeAfterUsingCoder: behaves basically like an 'init' method. It + // claims the receiver and returns a retained object. + addNSObjectMethSummary(GetUnarySelector("awakeAfterUsingCoder", Ctx), + InitSumm); + + // The next methods are allocators. + const RetainSummary *AllocSumm = getPersistentSummary(ObjCAllocRetE); + const RetainSummary *CFAllocSumm = + getPersistentSummary(RetEffect::MakeOwned(RetEffect::CF)); + + // Create the "retain" selector. + RetEffect NoRet = RetEffect::MakeNoRet(); + const RetainSummary *Summ = getPersistentSummary(NoRet, IncRefMsg); + addNSObjectMethSummary(GetNullarySelector("retain", Ctx), Summ); + + // Create the "release" selector. + Summ = getPersistentSummary(NoRet, DecRefMsg); + addNSObjectMethSummary(GetNullarySelector("release", Ctx), Summ); + + // Create the -dealloc summary. + Summ = getPersistentSummary(NoRet, Dealloc); + addNSObjectMethSummary(GetNullarySelector("dealloc", Ctx), Summ); + + // Create the "autorelease" selector. + Summ = getPersistentSummary(NoRet, Autorelease); + addNSObjectMethSummary(GetNullarySelector("autorelease", Ctx), Summ); + + // For NSWindow, allocated objects are (initially) self-owned. + // FIXME: For now we opt for false negatives with NSWindow, as these objects + // self-own themselves. However, they only do this once they are displayed. + // Thus, we need to track an NSWindow's display status. + // This is tracked in <rdar://problem/6062711>. + // See also http://llvm.org/bugs/show_bug.cgi?id=3714. + const RetainSummary *NoTrackYet = getPersistentSummary(RetEffect::MakeNoRet(), + StopTracking, + StopTracking); + + addClassMethSummary("NSWindow", "alloc", NoTrackYet); + + // For NSPanel (which subclasses NSWindow), allocated objects are not + // self-owned. + // FIXME: For now we don't track NSPanels. object for the same reason + // as for NSWindow objects. + addClassMethSummary("NSPanel", "alloc", NoTrackYet); + + // For NSNull, objects returned by +null are singletons that ignore + // retain/release semantics. Just don't track them. + // <rdar://problem/12858915> + addClassMethSummary("NSNull", "null", NoTrackYet); + + // Don't track allocated autorelease pools, as it is okay to prematurely + // exit a method. + addClassMethSummary("NSAutoreleasePool", "alloc", NoTrackYet); + addClassMethSummary("NSAutoreleasePool", "allocWithZone", NoTrackYet, false); + addClassMethSummary("NSAutoreleasePool", "new", NoTrackYet); + + // Create summaries QCRenderer/QCView -createSnapShotImageOfType: + addInstMethSummary("QCRenderer", AllocSumm, "createSnapshotImageOfType"); + addInstMethSummary("QCView", AllocSumm, "createSnapshotImageOfType"); + + // Create summaries for CIContext, 'createCGImage' and + // 'createCGLayerWithSize'. These objects are CF objects, and are not + // automatically garbage collected. + addInstMethSummary("CIContext", CFAllocSumm, "createCGImage", "fromRect"); + addInstMethSummary("CIContext", CFAllocSumm, "createCGImage", "fromRect", + "format", "colorSpace"); + addInstMethSummary("CIContext", CFAllocSumm, "createCGLayerWithSize", "info"); +} diff --git a/clang/lib/StaticAnalyzer/Checkers/RetainCountChecker/RetainCountSummaries.h b/clang/lib/StaticAnalyzer/Checkers/RetainCountChecker/RetainCountSummaries.h new file mode 100644 index 00000000000..2cd71b2a444 --- /dev/null +++ b/clang/lib/StaticAnalyzer/Checkers/RetainCountChecker/RetainCountSummaries.h @@ -0,0 +1,534 @@ +//=== RetainCountSummaries.h - Checks for leaks and other issues -*- 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 summaries implementation for RetainCountChecker, which +// implements a reference count checker for Core Foundation and Cocoa +// on (Mac OS X). +// +//===----------------------------------------------------------------------===// + +#ifndef LLVM_CLANG_LIB_STATICANALYZER_CHECKERS_RETAINCOUNTCHECKER_SUMMARY_H +#define LLVM_CLANG_LIB_STATICANALYZER_CHECKERS_RETAINCOUNTCHECKER_SUMMARY_H + +#include "../ClangSACheckers.h" +#include "../AllocationDiagnostics.h" +#include "../SelectorExtras.h" +#include "llvm/ADT/DenseMap.h" +#include "llvm/ADT/FoldingSet.h" +#include "clang/AST/Attr.h" +#include "clang/AST/DeclCXX.h" +#include "clang/AST/DeclObjC.h" +#include "clang/AST/ParentMap.h" +#include "clang/StaticAnalyzer/Checkers/ObjCRetainCount.h" +#include "clang/StaticAnalyzer/Core/BugReporter/BugType.h" +#include "clang/StaticAnalyzer/Core/BugReporter/PathDiagnostic.h" +#include "clang/StaticAnalyzer/Core/Checker.h" +#include "clang/StaticAnalyzer/Core/CheckerManager.h" +#include "clang/StaticAnalyzer/Core/PathSensitive/CallEvent.h" +#include "clang/StaticAnalyzer/Core/PathSensitive/CheckerContext.h" +#include "clang/StaticAnalyzer/Core/PathSensitive/ProgramStateTrait.h" +#include "clang/StaticAnalyzer/Core/PathSensitive/SymbolManager.h" +#include "llvm/ADT/ImmutableList.h" +#include "llvm/ADT/ImmutableMap.h" +#include "llvm/ADT/STLExtras.h" + +//===----------------------------------------------------------------------===// +// Adapters for FoldingSet. +//===----------------------------------------------------------------------===// + +using namespace clang; +using namespace ento; +using namespace objc_retain; + +namespace clang { +namespace ento { +namespace retaincountchecker { + +/// A key identifying a summary. +class ObjCSummaryKey { + IdentifierInfo* II; + Selector S; +public: + ObjCSummaryKey(IdentifierInfo* ii, Selector s) + : II(ii), S(s) {} + + ObjCSummaryKey(const ObjCInterfaceDecl *d, Selector s) + : II(d ? d->getIdentifier() : nullptr), S(s) {} + + ObjCSummaryKey(Selector s) + : II(nullptr), S(s) {} + + IdentifierInfo *getIdentifier() const { return II; } + Selector getSelector() const { return S; } +}; + +} // end namespace retaincountchecker +} // end namespace ento +} // end namespace clang + +namespace llvm { +using namespace retaincountchecker; + +template <> struct FoldingSetTrait<ArgEffect> { +static inline void Profile(const ArgEffect X, FoldingSetNodeID &ID) { + ID.AddInteger((unsigned) X); +} +}; +template <> struct FoldingSetTrait<RetEffect> { + static inline void Profile(const RetEffect &X, FoldingSetNodeID &ID) { + ID.AddInteger((unsigned) X.getKind()); + ID.AddInteger((unsigned) X.getObjKind()); +} +}; + +template <> struct DenseMapInfo<ObjCSummaryKey> { + static inline ObjCSummaryKey getEmptyKey() { + return ObjCSummaryKey(DenseMapInfo<IdentifierInfo*>::getEmptyKey(), + DenseMapInfo<Selector>::getEmptyKey()); + } + + static inline ObjCSummaryKey getTombstoneKey() { + return ObjCSummaryKey(DenseMapInfo<IdentifierInfo*>::getTombstoneKey(), + DenseMapInfo<Selector>::getTombstoneKey()); + } + + static unsigned getHashValue(const ObjCSummaryKey &V) { + typedef std::pair<IdentifierInfo*, Selector> PairTy; + return DenseMapInfo<PairTy>::getHashValue(PairTy(V.getIdentifier(), + V.getSelector())); + } + + static bool isEqual(const ObjCSummaryKey& LHS, const ObjCSummaryKey& RHS) { + return LHS.getIdentifier() == RHS.getIdentifier() && + LHS.getSelector() == RHS.getSelector(); + } + +}; + +} // end llvm namespace + + +namespace clang { +namespace ento { +namespace retaincountchecker { + +/// ArgEffects summarizes the effects of a function/method call on all of +/// its arguments. +typedef llvm::ImmutableMap<unsigned, ArgEffect> ArgEffects; + +/// Summary for a function with respect to ownership changes. +class RetainSummary { + /// Args - a map 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. + RetEffect Ret; + +public: + RetainSummary(ArgEffects A, RetEffect R, ArgEffect defaultEff, + ArgEffect ReceiverEff) + : Args(A), DefaultArgEffect(defaultEff), Receiver(ReceiverEff), Ret(R) {} + + /// getArg - Return the argument effect on the argument specified by + /// idx (starting from 0). + ArgEffect getArg(unsigned idx) const { + if (const ArgEffect *AE = Args.lookup(idx)) + return *AE; + + return DefaultArgEffect; + } + + void addArg(ArgEffects::Factory &af, unsigned idx, ArgEffect e) { + Args = af.add(Args, idx, e); + } + + /// setDefaultArgEffect - Set the default argument effect. + void setDefaultArgEffect(ArgEffect E) { + DefaultArgEffect = E; + } + + /// getRetEffect - Returns the effect on the return value of the call. + RetEffect getRetEffect() const { return Ret; } + + /// setRetEffect - Set the effect of the return value of the call. + void setRetEffect(RetEffect E) { Ret = E; } + + + /// Sets the effect on the receiver of the message. + void setReceiverEffect(ArgEffect e) { Receiver = e; } + + /// 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; } + + /// Test if two retain summaries are identical. Note that merely equivalent + /// summaries are not necessarily identical (for example, if an explicit + /// argument effect matches the default effect). + bool operator==(const RetainSummary &Other) const { + return Args == Other.Args && DefaultArgEffect == Other.DefaultArgEffect && + Receiver == Other.Receiver && Ret == Other.Ret; + } + + /// Profile this summary for inclusion in a FoldingSet. + void Profile(llvm::FoldingSetNodeID& ID) const { + ID.Add(Args); + ID.Add(DefaultArgEffect); + ID.Add(Receiver); + ID.Add(Ret); + } + + /// A retain summary is simple if it has no ArgEffects other than the default. + bool isSimple() const { + return Args.isEmpty(); + } + + + static bool isRetain(const FunctionDecl *FD, StringRef FName) { + return FName.startswith_lower("retain") || FName.endswith_lower("retain"); + } + + static bool isRelease(const FunctionDecl *FD, StringRef FName) { + return FName.startswith_lower("release") || FName.endswith_lower("release"); + } + + static bool isAutorelease(const FunctionDecl *FD, StringRef FName) { + return FName.startswith_lower("autorelease") || + FName.endswith_lower("autorelease"); + } + + static bool hasRCAnnotation(const Decl *D, StringRef rcAnnotation) { + for (const auto *Ann : D->specific_attrs<AnnotateAttr>()) { + if (Ann->getAnnotation() == rcAnnotation) + return true; + } + return false; + } + + static bool isTrustedReferenceCountImplementation(const FunctionDecl *FD) { + return hasRCAnnotation(FD, "rc_ownership_trusted_implementation"); + } + +private: + ArgEffects getArgEffects() const { return Args; } + ArgEffect getDefaultArgEffect() const { return DefaultArgEffect; } + + friend class RetainSummaryManager; + friend class RetainCountChecker; +}; + +class ObjCSummaryCache { + typedef llvm::DenseMap<ObjCSummaryKey, const RetainSummary *> MapTy; + MapTy M; +public: + ObjCSummaryCache() {} + + const RetainSummary * find(const 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()) + return I->second; + if (!D) + return nullptr; + + // 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 nullptr; + } + + // Cache the summary with original key to make the next lookup faster + // and return the iterator. + const RetainSummary *Summ = I->second; + M[K] = Summ; + return Summ; + } + + const RetainSummary *find(IdentifierInfo* II, Selector S) { + // FIXME: Class method lookup. Right now we don't have a good way + // of going between IdentifierInfo* and the class hierarchy. + MapTy::iterator I = M.find(ObjCSummaryKey(II, S)); + + if (I == M.end()) + I = M.find(ObjCSummaryKey(S)); + + return I == M.end() ? nullptr : I->second; + } + + const RetainSummary *& operator[](ObjCSummaryKey K) { + return M[K]; + } + + const RetainSummary *& operator[](Selector S) { + return M[ ObjCSummaryKey(S) ]; + } +}; + +class RetainSummaryManager { + typedef llvm::DenseMap<const FunctionDecl*, const RetainSummary *> + FuncSummariesTy; + + typedef ObjCSummaryCache ObjCMethodSummariesTy; + + typedef llvm::FoldingSetNodeWrapper<RetainSummary> CachedSummaryNode; + + /// Ctx - The ASTContext object for the analyzed ASTs. + ASTContext &Ctx; + + /// Records whether or not the analyzed code runs in ARC mode. + const bool ARCEnabled; + + /// 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; + + /// BPAlloc - A BumpPtrAllocator used for allocating summaries, ArgEffects, + /// and all other data used by the checker. + llvm::BumpPtrAllocator BPAlloc; + + /// AF - A factory for ArgEffects objects. + ArgEffects::Factory AF; + + /// ScratchArgs - A holding buffer for construct ArgEffects. + ArgEffects ScratchArgs; + + /// ObjCAllocRetE - Default return effect for methods returning Objective-C + /// objects. + RetEffect ObjCAllocRetE; + + /// ObjCInitRetE - Default return effect for init methods returning + /// Objective-C objects. + RetEffect ObjCInitRetE; + + /// SimpleSummaries - Used for uniquing summaries that don't have special + /// effects. + llvm::FoldingSet<CachedSummaryNode> SimpleSummaries; + + /// getArgEffects - Returns a persistent ArgEffects object based on the + /// data in ScratchArgs. + ArgEffects getArgEffects(); + + enum UnaryFuncKind { cfretain, cfrelease, cfautorelease }; + + const RetainSummary *getUnarySummary(const FunctionType* FT, + UnaryFuncKind func); + + const RetainSummary *getCFSummaryCreateRule(const FunctionDecl *FD); + const RetainSummary *getCFSummaryGetRule(const FunctionDecl *FD); + const RetainSummary *getCFCreateGetRuleSummary(const FunctionDecl *FD); + + const RetainSummary *getPersistentSummary(const RetainSummary &OldSumm); + + const RetainSummary *getPersistentSummary(RetEffect RetEff, + ArgEffect ReceiverEff = DoNothing, + ArgEffect DefaultEff = MayEscape) { + RetainSummary Summ(getArgEffects(), RetEff, DefaultEff, ReceiverEff); + return getPersistentSummary(Summ); + } + + const RetainSummary *getDoNothingSummary() { + return getPersistentSummary(RetEffect::MakeNoRet(), DoNothing, DoNothing); + } + + const RetainSummary *getDefaultSummary() { + return getPersistentSummary(RetEffect::MakeNoRet(), + DoNothing, MayEscape); + } + + const RetainSummary *getPersistentStopSummary() { + return getPersistentSummary(RetEffect::MakeNoRet(), + StopTracking, StopTracking); + } + + void InitializeClassMethodSummaries(); + void InitializeMethodSummaries(); +private: + void addNSObjectClsMethSummary(Selector S, const RetainSummary *Summ) { + ObjCClassMethodSummaries[S] = Summ; + } + + void addNSObjectMethSummary(Selector S, const RetainSummary *Summ) { + ObjCMethodSummaries[S] = Summ; + } + + void addClassMethSummary(const char* Cls, const char* name, + const RetainSummary *Summ, bool isNullary = true) { + IdentifierInfo* ClsII = &Ctx.Idents.get(Cls); + Selector S = isNullary ? GetNullarySelector(name, Ctx) + : GetUnarySelector(name, Ctx); + ObjCClassMethodSummaries[ObjCSummaryKey(ClsII, S)] = Summ; + } + + void addInstMethSummary(const char* Cls, const char* nullaryName, + const RetainSummary *Summ) { + IdentifierInfo* ClsII = &Ctx.Idents.get(Cls); + Selector S = GetNullarySelector(nullaryName, Ctx); + ObjCMethodSummaries[ObjCSummaryKey(ClsII, S)] = Summ; + } + + template <typename... Keywords> + void addMethodSummary(IdentifierInfo *ClsII, ObjCMethodSummariesTy &Summaries, + const RetainSummary *Summ, Keywords *... Kws) { + Selector S = getKeywordSelector(Ctx, Kws...); + Summaries[ObjCSummaryKey(ClsII, S)] = Summ; + } + + template <typename... Keywords> + void addInstMethSummary(const char *Cls, const RetainSummary *Summ, + Keywords *... Kws) { + addMethodSummary(&Ctx.Idents.get(Cls), ObjCMethodSummaries, Summ, Kws...); + } + + template <typename... Keywords> + void addClsMethSummary(const char *Cls, const RetainSummary *Summ, + Keywords *... Kws) { + addMethodSummary(&Ctx.Idents.get(Cls), ObjCClassMethodSummaries, Summ, + Kws...); + } + + template <typename... Keywords> + void addClsMethSummary(IdentifierInfo *II, const RetainSummary *Summ, + Keywords *... Kws) { + addMethodSummary(II, ObjCClassMethodSummaries, Summ, Kws...); + } + +public: + RetainSummaryManager(ASTContext &ctx, bool usesARC) + : Ctx(ctx), + ARCEnabled(usesARC), + AF(BPAlloc), ScratchArgs(AF.getEmptyMap()), + ObjCAllocRetE(usesARC ? RetEffect::MakeNotOwned(RetEffect::ObjC) + : RetEffect::MakeOwned(RetEffect::ObjC)), + ObjCInitRetE(usesARC ? RetEffect::MakeNotOwned(RetEffect::ObjC) + : RetEffect::MakeOwnedWhenTrackedReceiver()) { + InitializeClassMethodSummaries(); + InitializeMethodSummaries(); + } + + const RetainSummary *getSummary(const CallEvent &Call, + ProgramStateRef State = nullptr); + + const RetainSummary *getFunctionSummary(const FunctionDecl *FD); + + const RetainSummary *getMethodSummary(Selector S, const ObjCInterfaceDecl *ID, + const ObjCMethodDecl *MD, + QualType RetTy, + ObjCMethodSummariesTy &CachedSummaries); + + const RetainSummary *getInstanceMethodSummary(const ObjCMethodCall &M, + ProgramStateRef State); + + const RetainSummary *getClassMethodSummary(const ObjCMethodCall &M) { + assert(!M.isInstanceMessage()); + const ObjCInterfaceDecl *Class = M.getReceiverInterface(); + + return getMethodSummary(M.getSelector(), Class, M.getDecl(), + M.getResultType(), ObjCClassMethodSummaries); + } + + /// getMethodSummary - This version of getMethodSummary is used to query + /// the summary for the current method being analyzed. + const RetainSummary *getMethodSummary(const ObjCMethodDecl *MD) { + const ObjCInterfaceDecl *ID = MD->getClassInterface(); + Selector S = MD->getSelector(); + QualType ResultTy = MD->getReturnType(); + + ObjCMethodSummariesTy *CachedSummaries; + if (MD->isInstanceMethod()) + CachedSummaries = &ObjCMethodSummaries; + else + CachedSummaries = &ObjCClassMethodSummaries; + + return getMethodSummary(S, ID, MD, ResultTy, *CachedSummaries); + } + + const RetainSummary *getStandardMethodSummary(const ObjCMethodDecl *MD, + Selector S, QualType RetTy); + + /// Determine if there is a special return effect for this function or method. + Optional<RetEffect> getRetEffectFromAnnotations(QualType RetTy, + const Decl *D); + + void updateSummaryFromAnnotations(const RetainSummary *&Summ, + const ObjCMethodDecl *MD); + + void updateSummaryFromAnnotations(const RetainSummary *&Summ, + const FunctionDecl *FD); + + void updateSummaryForCall(const RetainSummary *&Summ, + const CallEvent &Call); + + bool isARCEnabled() const { return ARCEnabled; } + + RetEffect getObjAllocRetEffect() const { return ObjCAllocRetE; } + + friend class RetainSummaryTemplate; +}; + +// Used to avoid allocating long-term (BPAlloc'd) memory for default retain +// summaries. If a function or method looks like it has a default summary, but +// it has annotations, the annotations are added to the stack-based template +// and then copied into managed memory. +class RetainSummaryTemplate { + RetainSummaryManager &Manager; + const RetainSummary *&RealSummary; + RetainSummary ScratchSummary; + bool Accessed; +public: + RetainSummaryTemplate(const RetainSummary *&real, RetainSummaryManager &mgr) + : Manager(mgr), RealSummary(real), ScratchSummary(*real), Accessed(false) {} + + ~RetainSummaryTemplate() { + if (Accessed) + RealSummary = Manager.getPersistentSummary(ScratchSummary); + } + + RetainSummary &operator*() { + Accessed = true; + return ScratchSummary; + } + + RetainSummary *operator->() { + Accessed = true; + return &ScratchSummary; + } +}; + +} // end namespace retaincountchecker +} // end namespace ento +} // end namespace clang + +#endif |
