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//===-- CheckObjCInstMethSignature.cpp - Check ObjC method signatures -----===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
//
// This file defines a CheckObjCInstMethSignature, a flow-insensitive check
// that determines if an Objective-C class interface incorrectly redefines
// the method signature in a subclass.
//
//===----------------------------------------------------------------------===//
#include "clang/StaticAnalyzer/Checkers/BuiltinCheckerRegistration.h"
#include "clang/Analysis/PathDiagnostic.h"
#include "clang/AST/ASTContext.h"
#include "clang/AST/DeclObjC.h"
#include "clang/AST/Type.h"
#include "clang/StaticAnalyzer/Core/BugReporter/BugReporter.h"
#include "clang/StaticAnalyzer/Core/Checker.h"
#include "llvm/ADT/DenseMap.h"
#include "llvm/Support/raw_ostream.h"
using namespace clang;
using namespace ento;
static bool AreTypesCompatible(QualType Derived, QualType Ancestor,
ASTContext &C) {
// Right now don't compare the compatibility of pointers. That involves
// looking at subtyping relationships. FIXME: Future patch.
if (Derived->isAnyPointerType() && Ancestor->isAnyPointerType())
return true;
return C.typesAreCompatible(Derived, Ancestor);
}
static void CompareReturnTypes(const ObjCMethodDecl *MethDerived,
const ObjCMethodDecl *MethAncestor,
BugReporter &BR, ASTContext &Ctx,
const ObjCImplementationDecl *ID,
const CheckerBase *Checker) {
QualType ResDerived = MethDerived->getReturnType();
QualType ResAncestor = MethAncestor->getReturnType();
if (!AreTypesCompatible(ResDerived, ResAncestor, Ctx)) {
std::string sbuf;
llvm::raw_string_ostream os(sbuf);
os << "The Objective-C class '"
<< *MethDerived->getClassInterface()
<< "', which is derived from class '"
<< *MethAncestor->getClassInterface()
<< "', defines the instance method '";
MethDerived->getSelector().print(os);
os << "' whose return type is '"
<< ResDerived.getAsString()
<< "'. A method with the same name (same selector) is also defined in "
"class '"
<< *MethAncestor->getClassInterface()
<< "' and has a return type of '"
<< ResAncestor.getAsString()
<< "'. These two types are incompatible, and may result in undefined "
"behavior for clients of these classes.";
PathDiagnosticLocation MethDLoc =
PathDiagnosticLocation::createBegin(MethDerived,
BR.getSourceManager());
BR.EmitBasicReport(
MethDerived, Checker, "Incompatible instance method return type",
categories::CoreFoundationObjectiveC, os.str(), MethDLoc);
}
}
static void CheckObjCInstMethSignature(const ObjCImplementationDecl *ID,
BugReporter &BR,
const CheckerBase *Checker) {
const ObjCInterfaceDecl *D = ID->getClassInterface();
const ObjCInterfaceDecl *C = D->getSuperClass();
if (!C)
return;
ASTContext &Ctx = BR.getContext();
// Build a DenseMap of the methods for quick querying.
typedef llvm::DenseMap<Selector,ObjCMethodDecl*> MapTy;
MapTy IMeths;
unsigned NumMethods = 0;
for (auto *M : ID->instance_methods()) {
IMeths[M->getSelector()] = M;
++NumMethods;
}
// Now recurse the class hierarchy chain looking for methods with the
// same signatures.
while (C && NumMethods) {
for (const auto *M : C->instance_methods()) {
Selector S = M->getSelector();
MapTy::iterator MI = IMeths.find(S);
if (MI == IMeths.end() || MI->second == nullptr)
continue;
--NumMethods;
ObjCMethodDecl *MethDerived = MI->second;
MI->second = nullptr;
CompareReturnTypes(MethDerived, M, BR, Ctx, ID, Checker);
}
C = C->getSuperClass();
}
}
//===----------------------------------------------------------------------===//
// ObjCMethSigsChecker
//===----------------------------------------------------------------------===//
namespace {
class ObjCMethSigsChecker : public Checker<
check::ASTDecl<ObjCImplementationDecl> > {
public:
void checkASTDecl(const ObjCImplementationDecl *D, AnalysisManager& mgr,
BugReporter &BR) const {
CheckObjCInstMethSignature(D, BR, this);
}
};
}
void ento::registerObjCMethSigsChecker(CheckerManager &mgr) {
mgr.registerChecker<ObjCMethSigsChecker>();
}
bool ento::shouldRegisterObjCMethSigsChecker(const CheckerManager &mgr) {
return true;
}
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