1 //== BoolAssignmentChecker.cpp - Boolean assignment checker -----*- C++ -*--==// 2 // 3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. 4 // See https://llvm.org/LICENSE.txt for license information. 5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception 6 // 7 //===----------------------------------------------------------------------===// 8 // 9 // This defines BoolAssignmentChecker, a builtin check in ExprEngine that 10 // performs checks for assignment of non-Boolean values to Boolean variables. 11 // 12 //===----------------------------------------------------------------------===// 13 14 #include "clang/StaticAnalyzer/Checkers/BuiltinCheckerRegistration.h" 15 #include "clang/StaticAnalyzer/Core/BugReporter/BugType.h" 16 #include "clang/StaticAnalyzer/Core/Checker.h" 17 #include "clang/StaticAnalyzer/Core/CheckerManager.h" 18 #include "clang/StaticAnalyzer/Core/PathSensitive/CheckerContext.h" 19 20 using namespace clang; 21 using namespace ento; 22 23 namespace { 24 class BoolAssignmentChecker : public Checker< check::Bind > { 25 mutable std::unique_ptr<BuiltinBug> BT; 26 void emitReport(ProgramStateRef state, CheckerContext &C) const; 27 public: 28 void checkBind(SVal loc, SVal val, const Stmt *S, CheckerContext &C) const; 29 }; 30 } // end anonymous namespace 31 32 void BoolAssignmentChecker::emitReport(ProgramStateRef state, 33 CheckerContext &C) const { 34 if (ExplodedNode *N = C.generateNonFatalErrorNode(state)) { 35 if (!BT) 36 BT.reset(new BuiltinBug(this, "Assignment of a non-Boolean value")); 37 38 C.emitReport( 39 std::make_unique<PathSensitiveBugReport>(*BT, BT->getDescription(), N)); 40 } 41 } 42 43 static bool isBooleanType(QualType Ty) { 44 if (Ty->isBooleanType()) // C++ or C99 45 return true; 46 47 if (const TypedefType *TT = Ty->getAs<TypedefType>()) 48 return TT->getDecl()->getName() == "BOOL" || // Objective-C 49 TT->getDecl()->getName() == "_Bool" || // stdbool.h < C99 50 TT->getDecl()->getName() == "Boolean"; // MacTypes.h 51 52 return false; 53 } 54 55 void BoolAssignmentChecker::checkBind(SVal loc, SVal val, const Stmt *S, 56 CheckerContext &C) const { 57 58 // We are only interested in stores into Booleans. 59 const TypedValueRegion *TR = 60 dyn_cast_or_null<TypedValueRegion>(loc.getAsRegion()); 61 62 if (!TR) 63 return; 64 65 QualType valTy = TR->getValueType(); 66 67 if (!isBooleanType(valTy)) 68 return; 69 70 // Get the value of the right-hand side. We only care about values 71 // that are defined (UnknownVals and UndefinedVals are handled by other 72 // checkers). 73 Optional<NonLoc> NV = val.getAs<NonLoc>(); 74 if (!NV) 75 return; 76 77 // Check if the assigned value meets our criteria for correctness. It must 78 // be a value that is either 0 or 1. One way to check this is to see if 79 // the value is possibly < 0 (for a negative value) or greater than 1. 80 ProgramStateRef state = C.getState(); 81 SValBuilder &svalBuilder = C.getSValBuilder(); 82 BasicValueFactory &BVF = svalBuilder.getBasicValueFactory(); 83 ConstraintManager &CM = C.getConstraintManager(); 84 85 llvm::APSInt Zero = BVF.getValue(0, valTy); 86 llvm::APSInt One = BVF.getValue(1, valTy); 87 88 ProgramStateRef StIn, StOut; 89 std::tie(StIn, StOut) = CM.assumeInclusiveRangeDual(state, *NV, Zero, One); 90 91 if (!StIn) 92 emitReport(StOut, C); 93 } 94 95 void ento::registerBoolAssignmentChecker(CheckerManager &mgr) { 96 mgr.registerChecker<BoolAssignmentChecker>(); 97 } 98 99 bool ento::shouldRegisterBoolAssignmentChecker(const CheckerManager &mgr) { 100 return true; 101 } 102