clang  8.0.0svn
DeleteWithNonVirtualDtorChecker.cpp
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1 //===-- DeleteWithNonVirtualDtorChecker.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 // Defines a checker for the OOP52-CPP CERT rule: Do not delete a polymorphic
11 // object without a virtual destructor.
12 //
13 // Diagnostic flags -Wnon-virtual-dtor and -Wdelete-non-virtual-dtor report if
14 // an object with a virtual function but a non-virtual destructor exists or is
15 // deleted, respectively.
16 //
17 // This check exceeds them by comparing the dynamic and static types of the
18 // object at the point of destruction and only warns if it happens through a
19 // pointer to a base type without a virtual destructor. The check places a note
20 // at the last point where the conversion from derived to base happened.
21 //
22 //===----------------------------------------------------------------------===//
23 
24 #include "ClangSACheckers.h"
33 
34 using namespace clang;
35 using namespace ento;
36 
37 namespace {
38 class DeleteWithNonVirtualDtorChecker
39  : public Checker<check::PreStmt<CXXDeleteExpr>> {
40  mutable std::unique_ptr<BugType> BT;
41 
42  class DeleteBugVisitor : public BugReporterVisitor {
43  public:
44  DeleteBugVisitor() : Satisfied(false) {}
45  void Profile(llvm::FoldingSetNodeID &ID) const override {
46  static int X = 0;
47  ID.AddPointer(&X);
48  }
49  std::shared_ptr<PathDiagnosticPiece> VisitNode(const ExplodedNode *N,
50  BugReporterContext &BRC,
51  BugReport &BR) override;
52 
53  private:
54  bool Satisfied;
55  };
56 
57 public:
58  void checkPreStmt(const CXXDeleteExpr *DE, CheckerContext &C) const;
59 };
60 } // end anonymous namespace
61 
62 void DeleteWithNonVirtualDtorChecker::checkPreStmt(const CXXDeleteExpr *DE,
63  CheckerContext &C) const {
64  const Expr *DeletedObj = DE->getArgument();
65  const MemRegion *MR = C.getSVal(DeletedObj).getAsRegion();
66  if (!MR)
67  return;
68 
69  const auto *BaseClassRegion = MR->getAs<TypedValueRegion>();
70  const auto *DerivedClassRegion = MR->getBaseRegion()->getAs<SymbolicRegion>();
71  if (!BaseClassRegion || !DerivedClassRegion)
72  return;
73 
74  const auto *BaseClass = BaseClassRegion->getValueType()->getAsCXXRecordDecl();
75  const auto *DerivedClass =
76  DerivedClassRegion->getSymbol()->getType()->getPointeeCXXRecordDecl();
77  if (!BaseClass || !DerivedClass)
78  return;
79 
80  if (!BaseClass->hasDefinition() || !DerivedClass->hasDefinition())
81  return;
82 
83  if (BaseClass->getDestructor()->isVirtual())
84  return;
85 
86  if (!DerivedClass->isDerivedFrom(BaseClass))
87  return;
88 
89  if (!BT)
90  BT.reset(new BugType(this,
91  "Destruction of a polymorphic object with no "
92  "virtual destructor",
93  "Logic error"));
94 
95  ExplodedNode *N = C.generateNonFatalErrorNode();
96  auto R = llvm::make_unique<BugReport>(*BT, BT->getName(), N);
97 
98  // Mark region of problematic base class for later use in the BugVisitor.
99  R->markInteresting(BaseClassRegion);
100  R->addVisitor(llvm::make_unique<DeleteBugVisitor>());
101  C.emitReport(std::move(R));
102 }
103 
104 std::shared_ptr<PathDiagnosticPiece>
105 DeleteWithNonVirtualDtorChecker::DeleteBugVisitor::VisitNode(
106  const ExplodedNode *N, BugReporterContext &BRC,
107  BugReport &BR) {
108  // Stop traversal after the first conversion was found on a path.
109  if (Satisfied)
110  return nullptr;
111 
113  if (!S)
114  return nullptr;
115 
116  const auto *CastE = dyn_cast<CastExpr>(S);
117  if (!CastE)
118  return nullptr;
119 
120  // Only interested in DerivedToBase implicit casts.
121  // Explicit casts can have different CastKinds.
122  if (const auto *ImplCastE = dyn_cast<ImplicitCastExpr>(CastE)) {
123  if (ImplCastE->getCastKind() != CK_DerivedToBase)
124  return nullptr;
125  }
126 
127  // Region associated with the current cast expression.
128  const MemRegion *M = N->getSVal(CastE).getAsRegion();
129  if (!M)
130  return nullptr;
131 
132  // Check if target region was marked as problematic previously.
133  if (!BR.isInteresting(M))
134  return nullptr;
135 
136  // Stop traversal on this path.
137  Satisfied = true;
138 
139  SmallString<256> Buf;
140  llvm::raw_svector_ostream OS(Buf);
141  OS << "Conversion from derived to base happened here";
142  PathDiagnosticLocation Pos(S, BRC.getSourceManager(),
143  N->getLocationContext());
144  return std::make_shared<PathDiagnosticEventPiece>(Pos, OS.str(), true,
145  nullptr);
146 }
147 
148 void ento::registerDeleteWithNonVirtualDtorChecker(CheckerManager &mgr) {
149  mgr.registerChecker<DeleteWithNonVirtualDtorChecker>();
150 }
Stmt - This represents one statement.
Definition: Stmt.h:66
CastExpr - Base class for type casts, including both implicit casts (ImplicitCastExpr) and explicit c...
Definition: Expr.h:2917
This represents one expression.
Definition: Expr.h:106
const CXXRecordDecl * getPointeeCXXRecordDecl() const
If this is a pointer or reference to a RecordType, return the CXXRecordDecl that the type refers to...
Definition: Type.cpp:1598
QualType getType() const
Definition: Expr.h:128
static const Stmt * getStmt(const ExplodedNode *N)
Given an exploded node, retrieve the statement that should be used for the diagnostic location...
Expr * getArgument()
Definition: ExprCXX.h:2137
#define false
Definition: stdbool.h:33
Dataflow Directional Tag Classes.
Represents a delete expression for memory deallocation and destructor calls, e.g. ...
Definition: ExprCXX.h:2095
X
Add a minimal nested name specifier fixit hint to allow lookup of a tag name from an outer enclosing ...
Definition: SemaDecl.cpp:13956