| //===--- CallAndMessageChecker.cpp ------------------------------*- C++ -*--==// |
| // |
| // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. |
| // See https://llvm.org/LICENSE.txt for license information. |
| // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception |
| // |
| //===----------------------------------------------------------------------===// |
| // |
| // This defines CallAndMessageChecker, a builtin checker that checks for various |
| // errors of call and objc message expressions. |
| // |
| //===----------------------------------------------------------------------===// |
| |
| #include "clang/AST/ExprCXX.h" |
| #include "clang/AST/ParentMap.h" |
| #include "clang/Basic/TargetInfo.h" |
| #include "clang/StaticAnalyzer/Checkers/BuiltinCheckerRegistration.h" |
| #include "clang/StaticAnalyzer/Core/BugReporter/BugType.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 "llvm/ADT/SmallString.h" |
| #include "llvm/ADT/StringExtras.h" |
| #include "llvm/Support/Casting.h" |
| #include "llvm/Support/raw_ostream.h" |
| |
| using namespace clang; |
| using namespace ento; |
| |
| namespace { |
| |
| class CallAndMessageChecker |
| : public Checker<check::PreObjCMessage, check::ObjCMessageNil, |
| check::PreCall> { |
| mutable std::unique_ptr<BugType> BT_call_null; |
| mutable std::unique_ptr<BugType> BT_call_undef; |
| mutable std::unique_ptr<BugType> BT_cxx_call_null; |
| mutable std::unique_ptr<BugType> BT_cxx_call_undef; |
| mutable std::unique_ptr<BugType> BT_call_arg; |
| mutable std::unique_ptr<BugType> BT_cxx_delete_undef; |
| mutable std::unique_ptr<BugType> BT_msg_undef; |
| mutable std::unique_ptr<BugType> BT_objc_prop_undef; |
| mutable std::unique_ptr<BugType> BT_objc_subscript_undef; |
| mutable std::unique_ptr<BugType> BT_msg_arg; |
| mutable std::unique_ptr<BugType> BT_msg_ret; |
| mutable std::unique_ptr<BugType> BT_call_few_args; |
| |
| public: |
| // These correspond with the checker options. Looking at other checkers such |
| // as MallocChecker and CStringChecker, this is similar as to how they pull |
| // off having a modeling class, but emitting diagnostics under a smaller |
| // checker's name that can be safely disabled without disturbing the |
| // underlaying modeling engine. |
| // The reason behind having *checker options* rather then actual *checkers* |
| // here is that CallAndMessage is among the oldest checkers out there, and can |
| // be responsible for the majority of the reports on any given project. This |
| // is obviously not ideal, but changing checker name has the consequence of |
| // changing the issue hashes associated with the reports, and databases |
| // relying on this (CodeChecker, for instance) would suffer greatly. |
| // If we ever end up making changes to the issue hash generation algorithm, or |
| // the warning messages here, we should totally jump on the opportunity to |
| // convert these to actual checkers. |
| enum CheckKind { |
| CK_FunctionPointer, |
| CK_ParameterCount, |
| CK_CXXThisMethodCall, |
| CK_CXXDeallocationArg, |
| CK_ArgInitializedness, |
| CK_ArgPointeeInitializedness, |
| CK_NilReceiver, |
| CK_UndefReceiver, |
| CK_NumCheckKinds |
| }; |
| |
| DefaultBool ChecksEnabled[CK_NumCheckKinds]; |
| // The original core.CallAndMessage checker name. This should rather be an |
| // array, as seen in MallocChecker and CStringChecker. |
| CheckerNameRef OriginalName; |
| |
| void checkPreObjCMessage(const ObjCMethodCall &msg, CheckerContext &C) const; |
| |
| /// Fill in the return value that results from messaging nil based on the |
| /// return type and architecture and diagnose if the return value will be |
| /// garbage. |
| void checkObjCMessageNil(const ObjCMethodCall &msg, CheckerContext &C) const; |
| |
| void checkPreCall(const CallEvent &Call, CheckerContext &C) const; |
| |
| ProgramStateRef checkFunctionPointerCall(const CallExpr *CE, |
| CheckerContext &C, |
| ProgramStateRef State) const; |
| |
| ProgramStateRef checkCXXMethodCall(const CXXInstanceCall *CC, |
| CheckerContext &C, |
| ProgramStateRef State) const; |
| |
| ProgramStateRef checkParameterCount(const CallEvent &Call, CheckerContext &C, |
| ProgramStateRef State) const; |
| |
| ProgramStateRef checkCXXDeallocation(const CXXDeallocatorCall *DC, |
| CheckerContext &C, |
| ProgramStateRef State) const; |
| |
| ProgramStateRef checkArgInitializedness(const CallEvent &Call, |
| CheckerContext &C, |
| ProgramStateRef State) const; |
| |
| private: |
| bool PreVisitProcessArg(CheckerContext &C, SVal V, SourceRange ArgRange, |
| const Expr *ArgEx, int ArgumentNumber, |
| bool CheckUninitFields, const CallEvent &Call, |
| std::unique_ptr<BugType> &BT, |
| const ParmVarDecl *ParamDecl) const; |
| |
| static void emitBadCall(BugType *BT, CheckerContext &C, const Expr *BadE); |
| void emitNilReceiverBug(CheckerContext &C, const ObjCMethodCall &msg, |
| ExplodedNode *N) const; |
| |
| void HandleNilReceiver(CheckerContext &C, |
| ProgramStateRef state, |
| const ObjCMethodCall &msg) const; |
| |
| void LazyInit_BT(const char *desc, std::unique_ptr<BugType> &BT) const { |
| if (!BT) |
| BT.reset(new BuiltinBug(OriginalName, desc)); |
| } |
| bool uninitRefOrPointer(CheckerContext &C, const SVal &V, |
| SourceRange ArgRange, const Expr *ArgEx, |
| std::unique_ptr<BugType> &BT, |
| const ParmVarDecl *ParamDecl, const char *BD, |
| int ArgumentNumber) const; |
| }; |
| } // end anonymous namespace |
| |
| void CallAndMessageChecker::emitBadCall(BugType *BT, CheckerContext &C, |
| const Expr *BadE) { |
| ExplodedNode *N = C.generateErrorNode(); |
| if (!N) |
| return; |
| |
| auto R = std::make_unique<PathSensitiveBugReport>(*BT, BT->getDescription(), N); |
| if (BadE) { |
| R->addRange(BadE->getSourceRange()); |
| if (BadE->isGLValue()) |
| BadE = bugreporter::getDerefExpr(BadE); |
| bugreporter::trackExpressionValue(N, BadE, *R); |
| } |
| C.emitReport(std::move(R)); |
| } |
| |
| static void describeUninitializedArgumentInCall(const CallEvent &Call, |
| int ArgumentNumber, |
| llvm::raw_svector_ostream &Os) { |
| switch (Call.getKind()) { |
| case CE_ObjCMessage: { |
| const ObjCMethodCall &Msg = cast<ObjCMethodCall>(Call); |
| switch (Msg.getMessageKind()) { |
| case OCM_Message: |
| Os << (ArgumentNumber + 1) << llvm::getOrdinalSuffix(ArgumentNumber + 1) |
| << " argument in message expression is an uninitialized value"; |
| return; |
| case OCM_PropertyAccess: |
| assert(Msg.isSetter() && "Getters have no args"); |
| Os << "Argument for property setter is an uninitialized value"; |
| return; |
| case OCM_Subscript: |
| if (Msg.isSetter() && (ArgumentNumber == 0)) |
| Os << "Argument for subscript setter is an uninitialized value"; |
| else |
| Os << "Subscript index is an uninitialized value"; |
| return; |
| } |
| llvm_unreachable("Unknown message kind."); |
| } |
| case CE_Block: |
| Os << (ArgumentNumber + 1) << llvm::getOrdinalSuffix(ArgumentNumber + 1) |
| << " block call argument is an uninitialized value"; |
| return; |
| default: |
| Os << (ArgumentNumber + 1) << llvm::getOrdinalSuffix(ArgumentNumber + 1) |
| << " function call argument is an uninitialized value"; |
| return; |
| } |
| } |
| |
| bool CallAndMessageChecker::uninitRefOrPointer( |
| CheckerContext &C, const SVal &V, SourceRange ArgRange, const Expr *ArgEx, |
| std::unique_ptr<BugType> &BT, const ParmVarDecl *ParamDecl, const char *BD, |
| int ArgumentNumber) const { |
| |
| // The pointee being uninitialized is a sign of code smell, not a bug, no need |
| // to sink here. |
| if (!ChecksEnabled[CK_ArgPointeeInitializedness]) |
| return false; |
| |
| // No parameter declaration available, i.e. variadic function argument. |
| if(!ParamDecl) |
| return false; |
| |
| // If parameter is declared as pointer to const in function declaration, |
| // then check if corresponding argument in function call is |
| // pointing to undefined symbol value (uninitialized memory). |
| SmallString<200> Buf; |
| llvm::raw_svector_ostream Os(Buf); |
| |
| if (ParamDecl->getType()->isPointerType()) { |
| Os << (ArgumentNumber + 1) << llvm::getOrdinalSuffix(ArgumentNumber + 1) |
| << " function call argument is a pointer to uninitialized value"; |
| } else if (ParamDecl->getType()->isReferenceType()) { |
| Os << (ArgumentNumber + 1) << llvm::getOrdinalSuffix(ArgumentNumber + 1) |
| << " function call argument is an uninitialized value"; |
| } else |
| return false; |
| |
| if(!ParamDecl->getType()->getPointeeType().isConstQualified()) |
| return false; |
| |
| if (const MemRegion *SValMemRegion = V.getAsRegion()) { |
| const ProgramStateRef State = C.getState(); |
| const SVal PSV = State->getSVal(SValMemRegion, C.getASTContext().CharTy); |
| if (PSV.isUndef()) { |
| if (ExplodedNode *N = C.generateErrorNode()) { |
| LazyInit_BT(BD, BT); |
| auto R = std::make_unique<PathSensitiveBugReport>(*BT, Os.str(), N); |
| R->addRange(ArgRange); |
| if (ArgEx) |
| bugreporter::trackExpressionValue(N, ArgEx, *R); |
| |
| C.emitReport(std::move(R)); |
| } |
| return true; |
| } |
| } |
| return false; |
| } |
| |
| namespace { |
| class FindUninitializedField { |
| public: |
| SmallVector<const FieldDecl *, 10> FieldChain; |
| |
| private: |
| StoreManager &StoreMgr; |
| MemRegionManager &MrMgr; |
| Store store; |
| |
| public: |
| FindUninitializedField(StoreManager &storeMgr, MemRegionManager &mrMgr, |
| Store s) |
| : StoreMgr(storeMgr), MrMgr(mrMgr), store(s) {} |
| |
| bool Find(const TypedValueRegion *R) { |
| QualType T = R->getValueType(); |
| if (const RecordType *RT = T->getAsStructureType()) { |
| const RecordDecl *RD = RT->getDecl()->getDefinition(); |
| assert(RD && "Referred record has no definition"); |
| for (const auto *I : RD->fields()) { |
| const FieldRegion *FR = MrMgr.getFieldRegion(I, R); |
| FieldChain.push_back(I); |
| T = I->getType(); |
| if (T->getAsStructureType()) { |
| if (Find(FR)) |
| return true; |
| } else { |
| const SVal &V = StoreMgr.getBinding(store, loc::MemRegionVal(FR)); |
| if (V.isUndef()) |
| return true; |
| } |
| FieldChain.pop_back(); |
| } |
| } |
| |
| return false; |
| } |
| }; |
| } // namespace |
| |
| bool CallAndMessageChecker::PreVisitProcessArg(CheckerContext &C, |
| SVal V, |
| SourceRange ArgRange, |
| const Expr *ArgEx, |
| int ArgumentNumber, |
| bool CheckUninitFields, |
| const CallEvent &Call, |
| std::unique_ptr<BugType> &BT, |
| const ParmVarDecl *ParamDecl |
| ) const { |
| const char *BD = "Uninitialized argument value"; |
| |
| if (uninitRefOrPointer(C, V, ArgRange, ArgEx, BT, ParamDecl, BD, |
| ArgumentNumber)) |
| return true; |
| |
| if (V.isUndef()) { |
| if (!ChecksEnabled[CK_ArgInitializedness]) { |
| C.addSink(); |
| return true; |
| } |
| if (ExplodedNode *N = C.generateErrorNode()) { |
| LazyInit_BT(BD, BT); |
| // Generate a report for this bug. |
| SmallString<200> Buf; |
| llvm::raw_svector_ostream Os(Buf); |
| describeUninitializedArgumentInCall(Call, ArgumentNumber, Os); |
| auto R = std::make_unique<PathSensitiveBugReport>(*BT, Os.str(), N); |
| |
| R->addRange(ArgRange); |
| if (ArgEx) |
| bugreporter::trackExpressionValue(N, ArgEx, *R); |
| C.emitReport(std::move(R)); |
| } |
| return true; |
| } |
| |
| if (!CheckUninitFields) |
| return false; |
| |
| if (auto LV = V.getAs<nonloc::LazyCompoundVal>()) { |
| const LazyCompoundValData *D = LV->getCVData(); |
| FindUninitializedField F(C.getState()->getStateManager().getStoreManager(), |
| C.getSValBuilder().getRegionManager(), |
| D->getStore()); |
| |
| if (F.Find(D->getRegion())) { |
| if (!ChecksEnabled[CK_ArgInitializedness]) { |
| C.addSink(); |
| return true; |
| } |
| if (ExplodedNode *N = C.generateErrorNode()) { |
| LazyInit_BT(BD, BT); |
| SmallString<512> Str; |
| llvm::raw_svector_ostream os(Str); |
| os << "Passed-by-value struct argument contains uninitialized data"; |
| |
| if (F.FieldChain.size() == 1) |
| os << " (e.g., field: '" << *F.FieldChain[0] << "')"; |
| else { |
| os << " (e.g., via the field chain: '"; |
| bool first = true; |
| for (SmallVectorImpl<const FieldDecl *>::iterator |
| DI = F.FieldChain.begin(), DE = F.FieldChain.end(); DI!=DE;++DI){ |
| if (first) |
| first = false; |
| else |
| os << '.'; |
| os << **DI; |
| } |
| os << "')"; |
| } |
| |
| // Generate a report for this bug. |
| auto R = std::make_unique<PathSensitiveBugReport>(*BT, os.str(), N); |
| R->addRange(ArgRange); |
| |
| if (ArgEx) |
| bugreporter::trackExpressionValue(N, ArgEx, *R); |
| // FIXME: enhance track back for uninitialized value for arbitrary |
| // memregions |
| C.emitReport(std::move(R)); |
| } |
| return true; |
| } |
| } |
| |
| return false; |
| } |
| |
| ProgramStateRef CallAndMessageChecker::checkFunctionPointerCall( |
| const CallExpr *CE, CheckerContext &C, ProgramStateRef State) const { |
| |
| const Expr *Callee = CE->getCallee()->IgnoreParens(); |
| const LocationContext *LCtx = C.getLocationContext(); |
| SVal L = State->getSVal(Callee, LCtx); |
| |
| if (L.isUndef()) { |
| if (!ChecksEnabled[CK_FunctionPointer]) { |
| C.addSink(State); |
| return nullptr; |
| } |
| if (!BT_call_undef) |
| BT_call_undef.reset(new BuiltinBug( |
| OriginalName, |
| "Called function pointer is an uninitialized pointer value")); |
| emitBadCall(BT_call_undef.get(), C, Callee); |
| return nullptr; |
| } |
| |
| ProgramStateRef StNonNull, StNull; |
| std::tie(StNonNull, StNull) = State->assume(L.castAs<DefinedOrUnknownSVal>()); |
| |
| if (StNull && !StNonNull) { |
| if (!ChecksEnabled[CK_FunctionPointer]) { |
| C.addSink(StNull); |
| return nullptr; |
| } |
| if (!BT_call_null) |
| BT_call_null.reset(new BuiltinBug( |
| OriginalName, "Called function pointer is null (null dereference)")); |
| emitBadCall(BT_call_null.get(), C, Callee); |
| return nullptr; |
| } |
| |
| return StNonNull; |
| } |
| |
| ProgramStateRef CallAndMessageChecker::checkParameterCount( |
| const CallEvent &Call, CheckerContext &C, ProgramStateRef State) const { |
| |
| // If we have a function or block declaration, we can make sure we pass |
| // enough parameters. |
| unsigned Params = Call.parameters().size(); |
| if (Call.getNumArgs() >= Params) |
| return State; |
| |
| if (!ChecksEnabled[CK_ParameterCount]) { |
| C.addSink(State); |
| return nullptr; |
| } |
| |
| ExplodedNode *N = C.generateErrorNode(); |
| if (!N) |
| return nullptr; |
| |
| LazyInit_BT("Function call with too few arguments", BT_call_few_args); |
| |
| SmallString<512> Str; |
| llvm::raw_svector_ostream os(Str); |
| if (isa<AnyFunctionCall>(Call)) { |
| os << "Function "; |
| } else { |
| assert(isa<BlockCall>(Call)); |
| os << "Block "; |
| } |
| os << "taking " << Params << " argument" << (Params == 1 ? "" : "s") |
| << " is called with fewer (" << Call.getNumArgs() << ")"; |
| |
| C.emitReport( |
| std::make_unique<PathSensitiveBugReport>(*BT_call_few_args, os.str(), N)); |
| return nullptr; |
| } |
| |
| ProgramStateRef CallAndMessageChecker::checkCXXMethodCall( |
| const CXXInstanceCall *CC, CheckerContext &C, ProgramStateRef State) const { |
| |
| SVal V = CC->getCXXThisVal(); |
| if (V.isUndef()) { |
| if (!ChecksEnabled[CK_CXXThisMethodCall]) { |
| C.addSink(State); |
| return nullptr; |
| } |
| if (!BT_cxx_call_undef) |
| BT_cxx_call_undef.reset(new BuiltinBug( |
| OriginalName, "Called C++ object pointer is uninitialized")); |
| emitBadCall(BT_cxx_call_undef.get(), C, CC->getCXXThisExpr()); |
| return nullptr; |
| } |
| |
| ProgramStateRef StNonNull, StNull; |
| std::tie(StNonNull, StNull) = State->assume(V.castAs<DefinedOrUnknownSVal>()); |
| |
| if (StNull && !StNonNull) { |
| if (!ChecksEnabled[CK_CXXThisMethodCall]) { |
| C.addSink(StNull); |
| return nullptr; |
| } |
| if (!BT_cxx_call_null) |
| BT_cxx_call_null.reset( |
| new BuiltinBug(OriginalName, "Called C++ object pointer is null")); |
| emitBadCall(BT_cxx_call_null.get(), C, CC->getCXXThisExpr()); |
| return nullptr; |
| } |
| |
| return StNonNull; |
| } |
| |
| ProgramStateRef |
| CallAndMessageChecker::checkCXXDeallocation(const CXXDeallocatorCall *DC, |
| CheckerContext &C, |
| ProgramStateRef State) const { |
| const CXXDeleteExpr *DE = DC->getOriginExpr(); |
| assert(DE); |
| SVal Arg = C.getSVal(DE->getArgument()); |
| if (!Arg.isUndef()) |
| return State; |
| |
| if (!ChecksEnabled[CK_CXXDeallocationArg]) { |
| C.addSink(State); |
| return nullptr; |
| } |
| |
| StringRef Desc; |
| ExplodedNode *N = C.generateErrorNode(); |
| if (!N) |
| return nullptr; |
| if (!BT_cxx_delete_undef) |
| BT_cxx_delete_undef.reset( |
| new BuiltinBug(OriginalName, "Uninitialized argument value")); |
| if (DE->isArrayFormAsWritten()) |
| Desc = "Argument to 'delete[]' is uninitialized"; |
| else |
| Desc = "Argument to 'delete' is uninitialized"; |
| BugType *BT = BT_cxx_delete_undef.get(); |
| auto R = std::make_unique<PathSensitiveBugReport>(*BT, Desc, N); |
| bugreporter::trackExpressionValue(N, DE, *R); |
| C.emitReport(std::move(R)); |
| return nullptr; |
| } |
| |
| ProgramStateRef CallAndMessageChecker::checkArgInitializedness( |
| const CallEvent &Call, CheckerContext &C, ProgramStateRef State) const { |
| |
| const Decl *D = Call.getDecl(); |
| |
| // Don't check for uninitialized field values in arguments if the |
| // caller has a body that is available and we have the chance to inline it. |
| // This is a hack, but is a reasonable compromise betweens sometimes warning |
| // and sometimes not depending on if we decide to inline a function. |
| const bool checkUninitFields = |
| !(C.getAnalysisManager().shouldInlineCall() && (D && D->getBody())); |
| |
| std::unique_ptr<BugType> *BT; |
| if (isa<ObjCMethodCall>(Call)) |
| BT = &BT_msg_arg; |
| else |
| BT = &BT_call_arg; |
| |
| const FunctionDecl *FD = dyn_cast_or_null<FunctionDecl>(D); |
| for (unsigned i = 0, e = Call.getNumArgs(); i != e; ++i) { |
| const ParmVarDecl *ParamDecl = nullptr; |
| if (FD && i < FD->getNumParams()) |
| ParamDecl = FD->getParamDecl(i); |
| if (PreVisitProcessArg(C, Call.getArgSVal(i), Call.getArgSourceRange(i), |
| Call.getArgExpr(i), i, checkUninitFields, Call, *BT, |
| ParamDecl)) |
| return nullptr; |
| } |
| return State; |
| } |
| |
| void CallAndMessageChecker::checkPreCall(const CallEvent &Call, |
| CheckerContext &C) const { |
| ProgramStateRef State = C.getState(); |
| |
| if (const CallExpr *CE = dyn_cast_or_null<CallExpr>(Call.getOriginExpr())) |
| State = checkFunctionPointerCall(CE, C, State); |
| |
| if (!State) |
| return; |
| |
| if (Call.getDecl()) |
| State = checkParameterCount(Call, C, State); |
| |
| if (!State) |
| return; |
| |
| if (const auto *CC = dyn_cast<CXXInstanceCall>(&Call)) |
| State = checkCXXMethodCall(CC, C, State); |
| |
| if (!State) |
| return; |
| |
| if (const auto *DC = dyn_cast<CXXDeallocatorCall>(&Call)) |
| State = checkCXXDeallocation(DC, C, State); |
| |
| if (!State) |
| return; |
| |
| State = checkArgInitializedness(Call, C, State); |
| |
| // If we make it here, record our assumptions about the callee. |
| C.addTransition(State); |
| } |
| |
| void CallAndMessageChecker::checkPreObjCMessage(const ObjCMethodCall &msg, |
| CheckerContext &C) const { |
| SVal recVal = msg.getReceiverSVal(); |
| if (recVal.isUndef()) { |
| if (!ChecksEnabled[CK_UndefReceiver]) { |
| C.addSink(); |
| return; |
| } |
| if (ExplodedNode *N = C.generateErrorNode()) { |
| BugType *BT = nullptr; |
| switch (msg.getMessageKind()) { |
| case OCM_Message: |
| if (!BT_msg_undef) |
| BT_msg_undef.reset(new BuiltinBug(OriginalName, |
| "Receiver in message expression " |
| "is an uninitialized value")); |
| BT = BT_msg_undef.get(); |
| break; |
| case OCM_PropertyAccess: |
| if (!BT_objc_prop_undef) |
| BT_objc_prop_undef.reset(new BuiltinBug( |
| OriginalName, |
| "Property access on an uninitialized object pointer")); |
| BT = BT_objc_prop_undef.get(); |
| break; |
| case OCM_Subscript: |
| if (!BT_objc_subscript_undef) |
| BT_objc_subscript_undef.reset(new BuiltinBug( |
| OriginalName, |
| "Subscript access on an uninitialized object pointer")); |
| BT = BT_objc_subscript_undef.get(); |
| break; |
| } |
| assert(BT && "Unknown message kind."); |
| |
| auto R = std::make_unique<PathSensitiveBugReport>(*BT, BT->getDescription(), N); |
| const ObjCMessageExpr *ME = msg.getOriginExpr(); |
| R->addRange(ME->getReceiverRange()); |
| |
| // FIXME: getTrackNullOrUndefValueVisitor can't handle "super" yet. |
| if (const Expr *ReceiverE = ME->getInstanceReceiver()) |
| bugreporter::trackExpressionValue(N, ReceiverE, *R); |
| C.emitReport(std::move(R)); |
| } |
| return; |
| } |
| } |
| |
| void CallAndMessageChecker::checkObjCMessageNil(const ObjCMethodCall &msg, |
| CheckerContext &C) const { |
| HandleNilReceiver(C, C.getState(), msg); |
| } |
| |
| void CallAndMessageChecker::emitNilReceiverBug(CheckerContext &C, |
| const ObjCMethodCall &msg, |
| ExplodedNode *N) const { |
| if (!ChecksEnabled[CK_NilReceiver]) { |
| C.addSink(); |
| return; |
| } |
| |
| if (!BT_msg_ret) |
| BT_msg_ret.reset(new BuiltinBug(OriginalName, |
| "Receiver in message expression is 'nil'")); |
| |
| const ObjCMessageExpr *ME = msg.getOriginExpr(); |
| |
| QualType ResTy = msg.getResultType(); |
| |
| SmallString<200> buf; |
| llvm::raw_svector_ostream os(buf); |
| os << "The receiver of message '"; |
| ME->getSelector().print(os); |
| os << "' is nil"; |
| if (ResTy->isReferenceType()) { |
| os << ", which results in forming a null reference"; |
| } else { |
| os << " and returns a value of type '"; |
| msg.getResultType().print(os, C.getLangOpts()); |
| os << "' that will be garbage"; |
| } |
| |
| auto report = |
| std::make_unique<PathSensitiveBugReport>(*BT_msg_ret, os.str(), N); |
| report->addRange(ME->getReceiverRange()); |
| // FIXME: This won't track "self" in messages to super. |
| if (const Expr *receiver = ME->getInstanceReceiver()) { |
| bugreporter::trackExpressionValue(N, receiver, *report); |
| } |
| C.emitReport(std::move(report)); |
| } |
| |
| static bool supportsNilWithFloatRet(const llvm::Triple &triple) { |
| return (triple.getVendor() == llvm::Triple::Apple && |
| (triple.isiOS() || triple.isWatchOS() || |
| !triple.isMacOSXVersionLT(10,5))); |
| } |
| |
| void CallAndMessageChecker::HandleNilReceiver(CheckerContext &C, |
| ProgramStateRef state, |
| const ObjCMethodCall &Msg) const { |
| ASTContext &Ctx = C.getASTContext(); |
| static CheckerProgramPointTag Tag(this, "NilReceiver"); |
| |
| // Check the return type of the message expression. A message to nil will |
| // return different values depending on the return type and the architecture. |
| QualType RetTy = Msg.getResultType(); |
| CanQualType CanRetTy = Ctx.getCanonicalType(RetTy); |
| const LocationContext *LCtx = C.getLocationContext(); |
| |
| if (CanRetTy->isStructureOrClassType()) { |
| // Structure returns are safe since the compiler zeroes them out. |
| SVal V = C.getSValBuilder().makeZeroVal(RetTy); |
| C.addTransition(state->BindExpr(Msg.getOriginExpr(), LCtx, V), &Tag); |
| return; |
| } |
| |
| // Other cases: check if sizeof(return type) > sizeof(void*) |
| if (CanRetTy != Ctx.VoidTy && C.getLocationContext()->getParentMap() |
| .isConsumedExpr(Msg.getOriginExpr())) { |
| // Compute: sizeof(void *) and sizeof(return type) |
| const uint64_t voidPtrSize = Ctx.getTypeSize(Ctx.VoidPtrTy); |
| const uint64_t returnTypeSize = Ctx.getTypeSize(CanRetTy); |
| |
| if (CanRetTy.getTypePtr()->isReferenceType()|| |
| (voidPtrSize < returnTypeSize && |
| !(supportsNilWithFloatRet(Ctx.getTargetInfo().getTriple()) && |
| (Ctx.FloatTy == CanRetTy || |
| Ctx.DoubleTy == CanRetTy || |
| Ctx.LongDoubleTy == CanRetTy || |
| Ctx.LongLongTy == CanRetTy || |
| Ctx.UnsignedLongLongTy == CanRetTy)))) { |
| if (ExplodedNode *N = C.generateErrorNode(state, &Tag)) |
| emitNilReceiverBug(C, Msg, N); |
| return; |
| } |
| |
| // Handle the safe cases where the return value is 0 if the |
| // receiver is nil. |
| // |
| // FIXME: For now take the conservative approach that we only |
| // return null values if we *know* that the receiver is nil. |
| // This is because we can have surprises like: |
| // |
| // ... = [[NSScreens screens] objectAtIndex:0]; |
| // |
| // What can happen is that [... screens] could return nil, but |
| // it most likely isn't nil. We should assume the semantics |
| // of this case unless we have *a lot* more knowledge. |
| // |
| SVal V = C.getSValBuilder().makeZeroVal(RetTy); |
| C.addTransition(state->BindExpr(Msg.getOriginExpr(), LCtx, V), &Tag); |
| return; |
| } |
| |
| C.addTransition(state); |
| } |
| |
| void ento::registerCallAndMessageModeling(CheckerManager &mgr) { |
| mgr.registerChecker<CallAndMessageChecker>(); |
| } |
| |
| bool ento::shouldRegisterCallAndMessageModeling(const CheckerManager &mgr) { |
| return true; |
| } |
| |
| void ento::registerCallAndMessageChecker(CheckerManager &mgr) { |
| CallAndMessageChecker *checker = mgr.getChecker<CallAndMessageChecker>(); |
| |
| checker->OriginalName = mgr.getCurrentCheckerName(); |
| |
| #define QUERY_CHECKER_OPTION(OPTION) \ |
| checker->ChecksEnabled[CallAndMessageChecker::CK_##OPTION] = \ |
| mgr.getAnalyzerOptions().getCheckerBooleanOption( \ |
| mgr.getCurrentCheckerName(), #OPTION); |
| |
| QUERY_CHECKER_OPTION(FunctionPointer) |
| QUERY_CHECKER_OPTION(ParameterCount) |
| QUERY_CHECKER_OPTION(CXXThisMethodCall) |
| QUERY_CHECKER_OPTION(CXXDeallocationArg) |
| QUERY_CHECKER_OPTION(ArgInitializedness) |
| QUERY_CHECKER_OPTION(ArgPointeeInitializedness) |
| QUERY_CHECKER_OPTION(NilReceiver) |
| QUERY_CHECKER_OPTION(UndefReceiver) |
| } |
| |
| bool ento::shouldRegisterCallAndMessageChecker(const CheckerManager &mgr) { |
| return true; |
| } |
