contrib/llvm/tools/clang/lib/StaticAnalyzer/Checkers/CheckObjCInstMethSignature.cpp

   1 //=- CheckObjCInstMethodRetTy.cpp - Check ObjC method signatures -*- C++ -*-==//
   2 //
   3 //                     The LLVM Compiler Infrastructure
   4 //
   5 // This file is distributed under the University of Illinois Open Source
   6 // License. See LICENSE.TXT for details.
   7 //
   8 //===----------------------------------------------------------------------===//
   9 //
  10 //  This file defines a CheckObjCInstMethSignature, a flow-insenstive check
  11 //  that determines if an Objective-C class interface incorrectly redefines
  12 //  the method signature in a subclass.
  13 //
  14 //===----------------------------------------------------------------------===//
  15
  16 #include "ClangSACheckers.h"
  17 #include "clang/AST/ASTContext.h"
  18 #include "clang/AST/DeclObjC.h"
  19 #include "clang/AST/Type.h"
  20 #include "clang/StaticAnalyzer/Core/BugReporter/BugReporter.h"
  21 #include "clang/StaticAnalyzer/Core/BugReporter/PathDiagnostic.h"
  22 #include "clang/StaticAnalyzer/Core/Checker.h"
  23 #include "llvm/ADT/DenseMap.h"
  24 #include "llvm/Support/raw_ostream.h"
  25
  26 using namespace clang;
  27 using namespace ento;
  28
  29 static bool AreTypesCompatible(QualType Derived, QualType Ancestor,
  30                                ASTContext &C) {
  31
  32   // Right now don't compare the compatibility of pointers.  That involves
  33   // looking at subtyping relationships.  FIXME: Future patch.
  34   if (Derived->isAnyPointerType() &&  Ancestor->isAnyPointerType())
  35     return true;
  36
  37   return C.typesAreCompatible(Derived, Ancestor);
  38 }
  39
  40 static void CompareReturnTypes(const ObjCMethodDecl *MethDerived,
  41                                const ObjCMethodDecl *MethAncestor,
  42                                BugReporter &BR, ASTContext &Ctx,
  43                                const ObjCImplementationDecl *ID) {
  44
  45   QualType ResDerived  = MethDerived->getResultType();
  46   QualType ResAncestor = MethAncestor->getResultType();
  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().getAsString()
  58        << "' whose return type is '"
  59        << ResDerived.getAsString()
  60        << "'.  A method with the same name (same selector) is also defined in "
  61           "class '"
  62        << *MethAncestor->getClassInterface()
  63        << "' and has a return type of '"
  64        << ResAncestor.getAsString()
  65        << "'.  These two types are incompatible, and may result in undefined "
  66           "behavior for clients of these classes.";
  67
  68     PathDiagnosticLocation MethDLoc =
  69       PathDiagnosticLocation::createBegin(MethDerived,
  70                                           BR.getSourceManager());
  71
  72     BR.EmitBasicReport(MethDerived,
  73                        "Incompatible instance method return type",
  74                        categories::CoreFoundationObjectiveC,
  75                        os.str(), MethDLoc);
  76   }
  77 }
  78
  79 static void CheckObjCInstMethSignature(const ObjCImplementationDecl *ID,
  80                                        BugReporter& BR) {
  81
  82   const ObjCInterfaceDecl *D = ID->getClassInterface();
  83   const ObjCInterfaceDecl *C = D->getSuperClass();
  84
  85   if (!C)
  86     return;
  87
  88   ASTContext &Ctx = BR.getContext();
  89
  90   // Build a DenseMap of the methods for quick querying.
  91   typedef llvm::DenseMap<Selector,ObjCMethodDecl*> MapTy;
  92   MapTy IMeths;
  93   unsigned NumMethods = 0;
  94
  95   for (ObjCImplementationDecl::instmeth_iterator I=ID->instmeth_begin(),
  96        E=ID->instmeth_end(); I!=E; ++I) {
  97
  98     ObjCMethodDecl *M = *I;
  99     IMeths[M->getSelector()] = M;
 100     ++NumMethods;
 101   }
 102
 103   // Now recurse the class hierarchy chain looking for methods with the
 104   // same signatures.
 105   while (C && NumMethods) {
 106     for (ObjCInterfaceDecl::instmeth_iterator I=C->instmeth_begin(),
 107          E=C->instmeth_end(); I!=E; ++I) {
 108
 109       ObjCMethodDecl *M = *I;
 110       Selector S = M->getSelector();
 111
 112       MapTy::iterator MI = IMeths.find(S);
 113
 114       if (MI == IMeths.end() || MI->second == 0)
 115         continue;
 116
 117       --NumMethods;
 118       ObjCMethodDecl *MethDerived = MI->second;
 119       MI->second = 0;
 120
 121       CompareReturnTypes(MethDerived, M, BR, Ctx, ID);
 122     }
 123
 124     C = C->getSuperClass();
 125   }
 126 }
 127
 128 //===----------------------------------------------------------------------===//
 129 // ObjCMethSigsChecker
 130 //===----------------------------------------------------------------------===//
 131
 132 namespace {
 133 class ObjCMethSigsChecker : public Checker<
 134                                       check::ASTDecl<ObjCImplementationDecl> > {
 135 public:
 136   void checkASTDecl(const ObjCImplementationDecl *D, AnalysisManager& mgr,
 137                     BugReporter &BR) const {
 138     CheckObjCInstMethSignature(D, BR);
 139   }
 140 };
 141 }
 142
 143 void ento::registerObjCMethSigsChecker(CheckerManager &mgr) {
 144   mgr.registerChecker<ObjCMethSigsChecker>();
 145 }