1 //=== UndefResultChecker.cpp ------------------------------------*- C++ -*-===// 2 // 3 // The LLVM Compiler Infrastructure 4 // 5 // This file is distributed under the University of Illinois Open Source 6 // License. See LICENSE.TXT for details. 7 // 8 //===----------------------------------------------------------------------===// 9 // 10 // This defines UndefResultChecker, a builtin check in ExprEngine that 11 // performs checks for undefined results of non-assignment binary operators. 12 // 13 //===----------------------------------------------------------------------===// 14 15 #include "ClangSACheckers.h" 16 #include "clang/StaticAnalyzer/Core/Checker.h" 17 #include "clang/StaticAnalyzer/Core/CheckerManager.h" 18 #include "clang/StaticAnalyzer/Core/PathSensitive/CheckerContext.h" 19 #include "clang/StaticAnalyzer/Core/BugReporter/BugType.h" 20 #include "clang/StaticAnalyzer/Core/PathSensitive/ExprEngine.h" 21 22 using namespace clang; 23 using namespace ento; 24 25 namespace { 26 class UndefResultChecker 27 : public Checker< check::PostStmt<BinaryOperator> > { 28 29 mutable llvm::OwningPtr<BugType> BT; 30 31 public: 32 void checkPostStmt(const BinaryOperator *B, CheckerContext &C) const; 33 }; 34 } // end anonymous namespace 35 checkPostStmt(const BinaryOperator * B,CheckerContext & C) const36void UndefResultChecker::checkPostStmt(const BinaryOperator *B, 37 CheckerContext &C) const { 38 const GRState *state = C.getState(); 39 if (state->getSVal(B).isUndef()) { 40 // Generate an error node. 41 ExplodedNode *N = C.generateSink(); 42 if (!N) 43 return; 44 45 if (!BT) 46 BT.reset(new BuiltinBug("Result of operation is garbage or undefined")); 47 48 llvm::SmallString<256> sbuf; 49 llvm::raw_svector_ostream OS(sbuf); 50 const Expr *Ex = NULL; 51 bool isLeft = true; 52 53 if (state->getSVal(B->getLHS()).isUndef()) { 54 Ex = B->getLHS()->IgnoreParenCasts(); 55 isLeft = true; 56 } 57 else if (state->getSVal(B->getRHS()).isUndef()) { 58 Ex = B->getRHS()->IgnoreParenCasts(); 59 isLeft = false; 60 } 61 62 if (Ex) { 63 OS << "The " << (isLeft ? "left" : "right") 64 << " operand of '" 65 << BinaryOperator::getOpcodeStr(B->getOpcode()) 66 << "' is a garbage value"; 67 } 68 else { 69 // Neither operand was undefined, but the result is undefined. 70 OS << "The result of the '" 71 << BinaryOperator::getOpcodeStr(B->getOpcode()) 72 << "' expression is undefined"; 73 } 74 EnhancedBugReport *report = new EnhancedBugReport(*BT, OS.str(), N); 75 if (Ex) { 76 report->addRange(Ex->getSourceRange()); 77 report->addVisitorCreator(bugreporter::registerTrackNullOrUndefValue, Ex); 78 } 79 else 80 report->addVisitorCreator(bugreporter::registerTrackNullOrUndefValue, B); 81 C.EmitReport(report); 82 } 83 } 84 registerUndefResultChecker(CheckerManager & mgr)85void ento::registerUndefResultChecker(CheckerManager &mgr) { 86 mgr.registerChecker<UndefResultChecker>(); 87 } 88