clang  9.0.0
ObjCPropertyChecker.cpp
Go to the documentation of this file.
1 //==- ObjCPropertyChecker.cpp - Check ObjC properties ------------*- 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 checker finds issues with Objective-C properties.
10 // Currently finds only one kind of issue:
11 // - Find synthesized properties with copy attribute of mutable NS collection
12 // types. Calling -copy on such collections produces an immutable copy,
13 // which contradicts the type of the property.
14 //
15 //===----------------------------------------------------------------------===//
16 
20 
21 using namespace clang;
22 using namespace ento;
23 
24 namespace {
25 class ObjCPropertyChecker
26  : public Checker<check::ASTDecl<ObjCPropertyDecl>> {
27  void checkCopyMutable(const ObjCPropertyDecl *D, BugReporter &BR) const;
28 
29 public:
30  void checkASTDecl(const ObjCPropertyDecl *D, AnalysisManager &Mgr,
31  BugReporter &BR) const;
32 };
33 } // end anonymous namespace.
34 
35 void ObjCPropertyChecker::checkASTDecl(const ObjCPropertyDecl *D,
36  AnalysisManager &Mgr,
37  BugReporter &BR) const {
38  checkCopyMutable(D, BR);
39 }
40 
41 void ObjCPropertyChecker::checkCopyMutable(const ObjCPropertyDecl *D,
42  BugReporter &BR) const {
44  return;
45 
46  QualType T = D->getType();
47  if (!T->isObjCObjectPointerType())
48  return;
49 
50  const std::string &PropTypeName(T->getPointeeType().getCanonicalType()
52  .getAsString());
53  if (!StringRef(PropTypeName).startswith("NSMutable"))
54  return;
55 
56  const ObjCImplDecl *ImplD = nullptr;
57  if (const ObjCInterfaceDecl *IntD =
58  dyn_cast<ObjCInterfaceDecl>(D->getDeclContext())) {
59  ImplD = IntD->getImplementation();
60  } else if (auto *CatD = dyn_cast<ObjCCategoryDecl>(D->getDeclContext())) {
61  ImplD = CatD->getClassInterface()->getImplementation();
62  }
63 
64  if (!ImplD || ImplD->HasUserDeclaredSetterMethod(D))
65  return;
66 
67  SmallString<128> Str;
68  llvm::raw_svector_ostream OS(Str);
69  OS << "Property of mutable type '" << PropTypeName
70  << "' has 'copy' attribute; an immutable object will be stored instead";
71 
72  BR.EmitBasicReport(
73  D, this, "Objective-C property misuse", "Logic error", OS.str(),
74  PathDiagnosticLocation::createBegin(D, BR.getSourceManager()),
75  D->getSourceRange());
76 }
77 
78 void ento::registerObjCPropertyChecker(CheckerManager &Mgr) {
79  Mgr.registerChecker<ObjCPropertyChecker>();
80 }
81 
82 bool ento::shouldRegisterObjCPropertyChecker(const LangOptions &LO) {
83  return true;
84 }
A (possibly-)qualified type.
Definition: Type.h:643
QualType getPointeeType() const
If this is a pointer, ObjC object pointer, or block pointer, this returns the respective pointee...
Definition: Type.cpp:505
SetterKind getSetterKind() const
getSetterKind - Return the method used for doing assignment in the property setter.
Definition: DeclObjC.h:893
Keeps track of the various options that can be enabled, which controls the dialect of C or C++ that i...
Definition: LangOptions.h:49
bool isReadOnly() const
isReadOnly - Return true iff the property has a setter.
Definition: DeclObjC.h:862
Represents an ObjC class declaration.
Definition: DeclObjC.h:1171
bool HasUserDeclaredSetterMethod(const ObjCPropertyDecl *P) const
This routine returns &#39;true&#39; if a user declared setter method was found in the class, its protocols, its super classes or categories.
Definition: DeclObjC.cpp:123
DeclContext * getDeclContext()
Definition: DeclBase.h:438
QualType getType() const
Definition: DeclObjC.h:828
static PathDiagnosticLocation createBegin(const Decl *D, const SourceManager &SM)
Create a location for the beginning of the declaration.
QualType getCanonicalType() const
Definition: Type.h:6181
bool isObjCObjectPointerType() const
Definition: Type.h:6488
Represents one property declaration in an Objective-C interface.
Definition: DeclObjC.h:728
ObjCImplementationDecl * getImplementation() const
Definition: DeclObjC.cpp:1548
const ObjCInterfaceDecl * getClassInterface() const
Definition: DeclObjC.h:2439
Dataflow Directional Tag Classes.
SourceRange getSourceRange() const override LLVM_READONLY
Source range that this declaration covers.
Definition: DeclObjC.h:948
static std::string getAsString(SplitQualType split, const PrintingPolicy &Policy)
Definition: Type.h:976
Indicates that the tracking object is a descendant of a referenced-counted OSObject, used in the Darwin kernel.
QualType getUnqualifiedType() const
Retrieve the unqualified variant of the given type, removing as little sugar as possible.
Definition: Type.h:6222