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 36 void UndefResultChecker::checkPostStmt(const BinaryOperator *B, 37 CheckerContext &C) const { 38 ProgramStateRef state = C.getState(); 39 const LocationContext *LCtx = C.getLocationContext(); 40 if (state->getSVal(B, LCtx).isUndef()) { 41 // Generate an error node. 42 ExplodedNode *N = C.generateSink(); 43 if (!N) 44 return; 45 46 if (!BT) 47 BT.reset(new BuiltinBug("Result of operation is garbage or undefined")); 48 49 llvm::SmallString<256> sbuf; 50 llvm::raw_svector_ostream OS(sbuf); 51 const Expr *Ex = NULL; 52 bool isLeft = true; 53 54 if (state->getSVal(B->getLHS(), LCtx).isUndef()) { 55 Ex = B->getLHS()->IgnoreParenCasts(); 56 isLeft = true; 57 } 58 else if (state->getSVal(B->getRHS(), LCtx).isUndef()) { 59 Ex = B->getRHS()->IgnoreParenCasts(); 60 isLeft = false; 61 } 62 63 if (Ex) { 64 OS << "The " << (isLeft ? "left" : "right") 65 << " operand of '" 66 << BinaryOperator::getOpcodeStr(B->getOpcode()) 67 << "' is a garbage value"; 68 } 69 else { 70 // Neither operand was undefined, but the result is undefined. 71 OS << "The result of the '" 72 << BinaryOperator::getOpcodeStr(B->getOpcode()) 73 << "' expression is undefined"; 74 } 75 BugReport *report = new BugReport(*BT, OS.str(), N); 76 if (Ex) { 77 report->addRange(Ex->getSourceRange()); 78 report->addVisitor(bugreporter::getTrackNullOrUndefValueVisitor(N, Ex)); 79 } 80 else 81 report->addVisitor(bugreporter::getTrackNullOrUndefValueVisitor(N, B)); 82 C.EmitReport(report); 83 } 84 } 85 86 void ento::registerUndefResultChecker(CheckerManager &mgr) { 87 mgr.registerChecker<UndefResultChecker>(); 88 } 89