1 //=== CXXSelfAssignmentChecker.cpp -----------------------------*- 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 file defines CXXSelfAssignmentChecker, which tests all custom defined 10 // copy and move assignment operators for the case of self assignment, thus 11 // where the parameter refers to the same location where the this pointer 12 // points to. The checker itself does not do any checks at all, but it 13 // causes the analyzer to check every copy and move assignment operator twice: 14 // once for when 'this' aliases with the parameter and once for when it may not. 15 // It is the task of the other enabled checkers to find the bugs in these two 16 // different cases. 17 // 18 //===----------------------------------------------------------------------===// 19 20 #include "clang/StaticAnalyzer/Checkers/BuiltinCheckerRegistration.h" 21 #include "clang/StaticAnalyzer/Core/Checker.h" 22 #include "clang/StaticAnalyzer/Core/PathSensitive/CheckerContext.h" 23 24 using namespace clang; 25 using namespace ento; 26 27 namespace { 28 29 class CXXSelfAssignmentChecker : public Checker<check::BeginFunction> { 30 public: 31 CXXSelfAssignmentChecker(); 32 void checkBeginFunction(CheckerContext &C) const; 33 }; 34 } 35 36 CXXSelfAssignmentChecker::CXXSelfAssignmentChecker() {} 37 38 void CXXSelfAssignmentChecker::checkBeginFunction(CheckerContext &C) const { 39 if (!C.inTopFrame()) 40 return; 41 const auto *LCtx = C.getLocationContext(); 42 const auto *MD = dyn_cast<CXXMethodDecl>(LCtx->getDecl()); 43 if (!MD) 44 return; 45 if (!MD->isCopyAssignmentOperator() && !MD->isMoveAssignmentOperator()) 46 return; 47 auto &State = C.getState(); 48 auto &SVB = C.getSValBuilder(); 49 auto ThisVal = 50 State->getSVal(SVB.getCXXThis(MD, LCtx->getStackFrame())); 51 auto Param = SVB.makeLoc(State->getRegion(MD->getParamDecl(0), LCtx)); 52 auto ParamVal = State->getSVal(Param); 53 ProgramStateRef SelfAssignState = State->bindLoc(Param, ThisVal, LCtx); 54 C.addTransition(SelfAssignState); 55 ProgramStateRef NonSelfAssignState = State->bindLoc(Param, ParamVal, LCtx); 56 C.addTransition(NonSelfAssignState); 57 } 58 59 void ento::registerCXXSelfAssignmentChecker(CheckerManager &Mgr) { 60 Mgr.registerChecker<CXXSelfAssignmentChecker>(); 61 } 62