clang 18.0.0git
CheckObjCInstMethSignature.cpp
Go to the documentation of this file.
1//===-- CheckObjCInstMethSignature.cpp - Check ObjC method signatures -----===//
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 CheckObjCInstMethSignature, a flow-insensitive check
10// that determines if an Objective-C class interface incorrectly redefines
11// the method signature in a subclass.
12//
13//===----------------------------------------------------------------------===//
14
18#include "clang/AST/DeclObjC.h"
19#include "clang/AST/Type.h"
22#include "llvm/ADT/DenseMap.h"
23#include "llvm/Support/raw_ostream.h"
24
25using namespace clang;
26using namespace ento;
27
28static bool AreTypesCompatible(QualType Derived, QualType Ancestor,
29 ASTContext &C) {
30
31 // Right now don't compare the compatibility of pointers. That involves
32 // looking at subtyping relationships. FIXME: Future patch.
33 if (Derived->isAnyPointerType() && Ancestor->isAnyPointerType())
34 return true;
35
36 return C.typesAreCompatible(Derived, Ancestor);
37}
38
39static void CompareReturnTypes(const ObjCMethodDecl *MethDerived,
40 const ObjCMethodDecl *MethAncestor,
41 BugReporter &BR, ASTContext &Ctx,
42 const ObjCImplementationDecl *ID,
43 const CheckerBase *Checker) {
44
45 QualType ResDerived = MethDerived->getReturnType();
46 QualType ResAncestor = MethAncestor->getReturnType();
47
48 if (!AreTypesCompatible(ResDerived, ResAncestor, Ctx)) {
49 std::string sbuf;
50 llvm::raw_string_ostream os(sbuf);
51
52 os << "The Objective-C class '"
53 << *MethDerived->getClassInterface()
54 << "', which is derived from class '"
55 << *MethAncestor->getClassInterface()
56 << "', defines the instance method '";
57 MethDerived->getSelector().print(os);
58 os << "' whose return type is '" << ResDerived
59 << "'. A method with the same name (same selector) is also defined in "
60 "class '"
61 << *MethAncestor->getClassInterface() << "' and has a return type of '"
62 << ResAncestor
63 << "'. These two types are incompatible, and may result in undefined "
64 "behavior for clients of these classes.";
65
66 PathDiagnosticLocation MethDLoc =
68 BR.getSourceManager());
69
71 MethDerived, Checker, "Incompatible instance method return type",
72 categories::CoreFoundationObjectiveC, os.str(), MethDLoc);
73 }
74}
75
77 BugReporter &BR,
78 const CheckerBase *Checker) {
79
80 const ObjCInterfaceDecl *D = ID->getClassInterface();
81 const ObjCInterfaceDecl *C = D->getSuperClass();
82
83 if (!C)
84 return;
85
86 ASTContext &Ctx = BR.getContext();
87
88 // Build a DenseMap of the methods for quick querying.
89 typedef llvm::DenseMap<Selector,ObjCMethodDecl*> MapTy;
90 MapTy IMeths;
91 unsigned NumMethods = 0;
92
93 for (auto *M : ID->instance_methods()) {
94 IMeths[M->getSelector()] = M;
95 ++NumMethods;
96 }
97
98 // Now recurse the class hierarchy chain looking for methods with the
99 // same signatures.
100 while (C && NumMethods) {
101 for (const auto *M : C->instance_methods()) {
102 Selector S = M->getSelector();
103
104 MapTy::iterator MI = IMeths.find(S);
105
106 if (MI == IMeths.end() || MI->second == nullptr)
107 continue;
108
109 --NumMethods;
110 ObjCMethodDecl *MethDerived = MI->second;
111 MI->second = nullptr;
112
113 CompareReturnTypes(MethDerived, M, BR, Ctx, ID, Checker);
114 }
115
116 C = C->getSuperClass();
117 }
118}
119
120//===----------------------------------------------------------------------===//
121// ObjCMethSigsChecker
122//===----------------------------------------------------------------------===//
123
124namespace {
125class ObjCMethSigsChecker : public Checker<
126 check::ASTDecl<ObjCImplementationDecl> > {
127public:
128 void checkASTDecl(const ObjCImplementationDecl *D, AnalysisManager& mgr,
129 BugReporter &BR) const {
130 CheckObjCInstMethSignature(D, BR, this);
131 }
132};
133}
134
135void ento::registerObjCMethSigsChecker(CheckerManager &mgr) {
136 mgr.registerChecker<ObjCMethSigsChecker>();
137}
138
139bool ento::shouldRegisterObjCMethSigsChecker(const CheckerManager &mgr) {
140 return true;
141}
Defines the clang::ASTContext interface.
static bool AreTypesCompatible(QualType Derived, QualType Ancestor, ASTContext &C)
static void CheckObjCInstMethSignature(const ObjCImplementationDecl *ID, BugReporter &BR, const CheckerBase *Checker)
static void CompareReturnTypes(const ObjCMethodDecl *MethDerived, const ObjCMethodDecl *MethAncestor, BugReporter &BR, ASTContext &Ctx, const ObjCImplementationDecl *ID, const CheckerBase *Checker)
llvm::DenseMap< Stmt *, Stmt * > MapTy
Definition: ParentMap.cpp:22
C Language Family Type Representation.
Holds long-lived AST nodes (such as types and decls) that can be referred to throughout the semantic ...
Definition: ASTContext.h:182
ObjCImplementationDecl - Represents a class definition - this is where method definitions are specifi...
Definition: DeclObjC.h:2595
Represents an ObjC class declaration.
Definition: DeclObjC.h:1150
ObjCInterfaceDecl * getSuperClass() const
Definition: DeclObjC.cpp:351
ObjCMethodDecl - Represents an instance or class method declaration.
Definition: DeclObjC.h:140
Selector getSelector() const
Definition: DeclObjC.h:327
QualType getReturnType() const
Definition: DeclObjC.h:329
ObjCInterfaceDecl * getClassInterface()
Definition: DeclObjC.cpp:1211
A (possibly-)qualified type.
Definition: Type.h:736
Smart pointer class that efficiently represents Objective-C method names.
void print(llvm::raw_ostream &OS) const
Prints the full selector name (e.g. "foo:bar:").
bool isAnyPointerType() const
Definition: Type.h:7037
BugReporter is a utility class for generating PathDiagnostics for analysis.
Definition: BugReporter.h:584
const SourceManager & getSourceManager()
Definition: BugReporter.h:616
void EmitBasicReport(const Decl *DeclWithIssue, const CheckerBase *Checker, StringRef BugName, StringRef BugCategory, StringRef BugStr, PathDiagnosticLocation Loc, ArrayRef< SourceRange > Ranges=std::nullopt, ArrayRef< FixItHint > Fixits=std::nullopt)
ASTContext & getContext()
Definition: BugReporter.h:614
CHECKER * registerChecker(AT &&... Args)
Used to register checkers.
static PathDiagnosticLocation createBegin(const Decl *D, const SourceManager &SM)
Create a location for the beginning of the declaration.
const char *const CoreFoundationObjectiveC