clang  10.0.0git
SmartPtrModeling.cpp
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1 // SmartPtrModeling.cpp - Model behavior of C++ smart pointers - 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 a checker that models various aspects of
10 // C++ smart pointer behavior.
11 //
12 //===----------------------------------------------------------------------===//
13 
14 #include "Move.h"
15 
16 #include "clang/AST/ExprCXX.h"
23 
24 using namespace clang;
25 using namespace ento;
26 
27 namespace {
28 class SmartPtrModeling : public Checker<eval::Call> {
29  bool isNullAfterMoveMethod(const CallEvent &Call) const;
30 
31 public:
32  bool evalCall(const CallEvent &Call, CheckerContext &C) const;
33 };
34 } // end of anonymous namespace
35 
36 bool SmartPtrModeling::isNullAfterMoveMethod(const CallEvent &Call) const {
37  // TODO: Update CallDescription to support anonymous calls?
38  // TODO: Handle other methods, such as .get() or .release().
39  // But once we do, we'd need a visitor to explain null dereferences
40  // that are found via such modeling.
41  const auto *CD = dyn_cast_or_null<CXXConversionDecl>(Call.getDecl());
42  return CD && CD->getConversionType()->isBooleanType();
43 }
44 
45 bool SmartPtrModeling::evalCall(const CallEvent &Call,
46  CheckerContext &C) const {
47  if (!isNullAfterMoveMethod(Call))
48  return false;
49 
50  ProgramStateRef State = C.getState();
51  const MemRegion *ThisR =
52  cast<CXXInstanceCall>(&Call)->getCXXThisVal().getAsRegion();
53 
54  if (!move::isMovedFrom(State, ThisR)) {
55  // TODO: Model this case as well. At least, avoid invalidation of globals.
56  return false;
57  }
58 
59  // TODO: Add a note to bug reports describing this decision.
60  C.addTransition(
61  State->BindExpr(Call.getOriginExpr(), C.getLocationContext(),
62  C.getSValBuilder().makeZeroVal(Call.getResultType())));
63  return true;
64 }
65 
66 void ento::registerSmartPtrModeling(CheckerManager &Mgr) {
67  Mgr.registerChecker<SmartPtrModeling>();
68 }
69 
70 bool ento::shouldRegisterSmartPtrModeling(const LangOptions &LO) {
71  return LO.CPlusPlus;
72 }
IntrusiveRefCntPtr< const ProgramState > ProgramStateRef
Defines the clang::Expr interface and subclasses for C++ expressions.
LineState State
Keeps track of the various options that can be enabled, which controls the dialect of C or C++ that i...
Definition: LangOptions.h:53
bool isMovedFrom(ProgramStateRef State, const MemRegion *Region)
Returns true if the object is known to have been recently std::moved.
Dataflow Directional Tag Classes.