1 //=== CXXSelfAssignmentChecker.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 file defines CXXSelfAssignmentChecker, which tests all custom defined 11 // copy and move assignment operators for the case of self assignment, thus 12 // where the parameter refers to the same location where the this pointer 13 // points to. The checker itself does not do any checks at all, but it 14 // causes the analyzer to check every copy and move assignment operator twice: 15 // once for when 'this' aliases with the parameter and once for when it may not. 16 // It is the task of the other enabled checkers to find the bugs in these two 17 // different cases. 18 // 19 //===----------------------------------------------------------------------===// 20 21 #include "ClangSACheckers.h" 22 #include "clang/StaticAnalyzer/Core/Checker.h" 23 #include "clang/StaticAnalyzer/Core/PathSensitive/CheckerContext.h" 24 25 using namespace clang; 26 using namespace ento; 27 28 namespace { 29 30 class CXXSelfAssignmentChecker : public Checker<check::BeginFunction> { 31 public: 32 CXXSelfAssignmentChecker(); 33 void checkBeginFunction(CheckerContext &C) const; 34 }; 35 } 36 37 CXXSelfAssignmentChecker::CXXSelfAssignmentChecker() {} 38 39 void CXXSelfAssignmentChecker::checkBeginFunction(CheckerContext &C) const { 40 if (!C.inTopFrame()) 41 return; 42 const auto *LCtx = C.getLocationContext(); 43 const auto *MD = dyn_cast<CXXMethodDecl>(LCtx->getDecl()); 44 if (!MD) 45 return; 46 if (!MD->isCopyAssignmentOperator() && !MD->isMoveAssignmentOperator()) 47 return; 48 auto &State = C.getState(); 49 auto &SVB = C.getSValBuilder(); 50 auto ThisVal = 51 State->getSVal(SVB.getCXXThis(MD, LCtx->getStackFrame())); 52 auto Param = SVB.makeLoc(State->getRegion(MD->getParamDecl(0), LCtx)); 53 auto ParamVal = State->getSVal(Param); 54 ProgramStateRef SelfAssignState = State->bindLoc(Param, ThisVal, LCtx); 55 C.addTransition(SelfAssignState); 56 ProgramStateRef NonSelfAssignState = State->bindLoc(Param, ParamVal, LCtx); 57 C.addTransition(NonSelfAssignState); 58 } 59 60 void ento::registerCXXSelfAssignmentChecker(CheckerManager &Mgr) { 61 Mgr.registerChecker<CXXSelfAssignmentChecker>(); 62 } 63