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  const ExplodedNode *PrevN,
51  BugReporterContext &BRC,
52  BugReport &BR) override;
53 
54  private:
55  bool Satisfied;
56  };
57 
58 public:
59  void checkPreStmt(const CXXDeleteExpr *DE, CheckerContext &C) const;
60 };
61 } // end anonymous namespace
62 
63 void DeleteWithNonVirtualDtorChecker::checkPreStmt(const CXXDeleteExpr *DE,
64  CheckerContext &C) const {
65  const Expr *DeletedObj = DE->getArgument();
66  const MemRegion *MR = C.getSVal(DeletedObj).getAsRegion();
67  if (!MR)
68  return;
69 
70  const auto *BaseClassRegion = MR->getAs<TypedValueRegion>();
71  const auto *DerivedClassRegion = MR->getBaseRegion()->getAs<SymbolicRegion>();
72  if (!BaseClassRegion || !DerivedClassRegion)
73  return;
74 
75  const auto *BaseClass = BaseClassRegion->getValueType()->getAsCXXRecordDecl();
76  const auto *DerivedClass =
77  DerivedClassRegion->getSymbol()->getType()->getPointeeCXXRecordDecl();
78  if (!BaseClass || !DerivedClass)
79  return;
80 
81  if (!BaseClass->hasDefinition() || !DerivedClass->hasDefinition())
82  return;
83 
84  if (BaseClass->getDestructor()->isVirtual())
85  return;
86 
87  if (!DerivedClass->isDerivedFrom(BaseClass))
88  return;
89 
90  if (!BT)
91  BT.reset(new BugType(this,
92  "Destruction of a polymorphic object with no "
93  "virtual destructor",
94  "Logic error"));
95 
96  ExplodedNode *N = C.generateNonFatalErrorNode();
97  auto R = llvm::make_unique<BugReport>(*BT, BT->getName(), N);
98 
99  // Mark region of problematic base class for later use in the BugVisitor.
100  R->markInteresting(BaseClassRegion);
101  R->addVisitor(llvm::make_unique<DeleteBugVisitor>());
102  C.emitReport(std::move(R));
103 }
104 
105 std::shared_ptr<PathDiagnosticPiece>
106 DeleteWithNonVirtualDtorChecker::DeleteBugVisitor::VisitNode(
107  const ExplodedNode *N, const ExplodedNode *PrevN, BugReporterContext &BRC,
108  BugReport &BR) {
109  // Stop traversal after the first conversion was found on a path.
110  if (Satisfied)
111  return nullptr;
112 
114  if (!S)
115  return nullptr;
116 
117  const auto *CastE = dyn_cast<CastExpr>(S);
118  if (!CastE)
119  return nullptr;
120 
121  // Only interested in DerivedToBase implicit casts.
122  // Explicit casts can have different CastKinds.
123  if (const auto *ImplCastE = dyn_cast<ImplicitCastExpr>(CastE)) {
124  if (ImplCastE->getCastKind() != CK_DerivedToBase)
125  return nullptr;
126  }
127 
128  // Region associated with the current cast expression.
129  const MemRegion *M = N->getSVal(CastE).getAsRegion();
130  if (!M)
131  return nullptr;
132 
133  // Check if target region was marked as problematic previously.
134  if (!BR.isInteresting(M))
135  return nullptr;
136 
137  // Stop traversal on this path.
138  Satisfied = true;
139 
140  SmallString<256> Buf;
141  llvm::raw_svector_ostream OS(Buf);
142  OS << "Conversion from derived to base happened here";
143  PathDiagnosticLocation Pos(S, BRC.getSourceManager(),
144  N->getLocationContext());
145  return std::make_shared<PathDiagnosticEventPiece>(Pos, OS.str(), true,
146  nullptr);
147 }
148 
149 void ento::registerDeleteWithNonVirtualDtorChecker(CheckerManager &mgr) {
150  mgr.registerChecker<DeleteWithNonVirtualDtorChecker>();
151 }
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:2790
This represents one expression.
Definition: Expr.h:105
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:1590
QualType getType() const
Definition: Expr.h:127
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:2154
#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:2100
X
Add a minimal nested name specifier fixit hint to allow lookup of a tag name from an outer enclosing ...
Definition: SemaDecl.cpp:13826