clang  14.0.0git
CXXSelfAssignmentChecker.cpp
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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 
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 
54  ProgramStateRef SelfAssignState = State->bindLoc(Param, ThisVal, LCtx);
55  const NoteTag *SelfAssignTag =
56  C.getNoteTag([MD](PathSensitiveBugReport &BR) -> std::string {
57  SmallString<256> Msg;
58  llvm::raw_svector_ostream Out(Msg);
59  Out << "Assuming " << MD->getParamDecl(0)->getName() << " == *this";
60  return std::string(Out.str());
61  });
62  C.addTransition(SelfAssignState, SelfAssignTag);
63 
64  ProgramStateRef NonSelfAssignState = State->bindLoc(Param, ParamVal, LCtx);
65  const NoteTag *NonSelfAssignTag =
66  C.getNoteTag([MD](PathSensitiveBugReport &BR) -> std::string {
67  SmallString<256> Msg;
68  llvm::raw_svector_ostream Out(Msg);
69  Out << "Assuming " << MD->getParamDecl(0)->getName() << " != *this";
70  return std::string(Out.str());
71  });
72  C.addTransition(NonSelfAssignState, NonSelfAssignTag);
73 }
74 
75 void ento::registerCXXSelfAssignmentChecker(CheckerManager &Mgr) {
76  Mgr.registerChecker<CXXSelfAssignmentChecker>();
77 }
78 
79 bool ento::shouldRegisterCXXSelfAssignmentChecker(const CheckerManager &mgr) {
80  return true;
81 }
string
string(SUBSTRING ${CMAKE_CURRENT_BINARY_DIR} 0 ${PATH_LIB_START} PATH_HEAD) string(SUBSTRING $
Definition: CMakeLists.txt:22
clang::ento::ProgramStateRef
IntrusiveRefCntPtr< const ProgramState > ProgramStateRef
Definition: ProgramState_Fwd.h:37
AttributeLangSupport::C
@ C
Definition: SemaDeclAttr.cpp:54
BuiltinCheckerRegistration.h
llvm::SmallString
Definition: LLVM.h:37
State
LineState State
Definition: UnwrappedLineFormatter.cpp:986
CheckerContext.h
Checker.h
clang
Definition: CalledOnceCheck.h:17