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
17#include "clang/StaticAnalyzer/Checkers/BuiltinCheckerRegistration.h"
18#include "clang/StaticAnalyzer/Core/BugReporter/BugReporter.h"
19#include "clang/StaticAnalyzer/Core/Checker.h"
20
21using namespace clang;
22using namespace ento;
23
24namespace {
25class ObjCPropertyChecker
26 : public Checker<check::ASTDecl<ObjCPropertyDecl>> {
27 void checkCopyMutable(const ObjCPropertyDecl *D, BugReporter &BR) const;
28
29public:
30 void checkASTDecl(const ObjCPropertyDecl *D, AnalysisManager &Mgr,
31 BugReporter &BR) const;
32};
33} // end anonymous namespace.
34
35void ObjCPropertyChecker::checkASTDecl(const ObjCPropertyDecl *D,
36 AnalysisManager &Mgr,
37 BugReporter &BR) const {
38 checkCopyMutable(D, BR);
39}
40
41void ObjCPropertyChecker::checkCopyMutable(const ObjCPropertyDecl *D,
42 BugReporter &BR) const {
43 if (D->isReadOnly() || D->getSetterKind() != ObjCPropertyDecl::Copy)
44 return;
45
46 QualType T = D->getType();
47 if (!T->isObjCObjectPointerType())
48 return;
49
50 const std::string &PropTypeName(T->getPointeeType().getCanonicalType()
51 .getUnqualifiedType()
52 .getAsString());
53 if (!StringRef(PropTypeName).starts_with(Prefix: "NSMutable"))
54 return;
55
56 const ObjCImplDecl *ImplD = nullptr;
57 if (const ObjCInterfaceDecl *IntD =
58 dyn_cast<ObjCInterfaceDecl>(Val: D->getDeclContext())) {
59 ImplD = IntD->getImplementation();
60 } else if (auto *CatD = dyn_cast<ObjCCategoryDecl>(Val: D->getDeclContext())) {
61 ImplD = CatD->getClassInterface()->getImplementation();
62 }
63
64 if (!ImplD || ImplD->HasUserDeclaredSetterMethod(P: 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 DeclWithIssue: D, Checker: this, BugName: "Objective-C property misuse", BugCategory: "Logic error", BugStr: OS.str(),
74 Loc: PathDiagnosticLocation::createBegin(D, SM: BR.getSourceManager()),
75 Ranges: D->getSourceRange());
76}
77
78void ento::registerObjCPropertyChecker(CheckerManager &Mgr) {
79 Mgr.registerChecker<ObjCPropertyChecker>();
80}
81
82bool ento::shouldRegisterObjCPropertyChecker(const CheckerManager &mgr) {
83 return true;
84}
85