C++ IvarUsageMap::begin方法代码示例

void clang::CheckObjCUnusedIvar(ObjCImplementationDecl* D, BugReporter& BR) {

    ObjCInterfaceDecl* ID = D->getClassInterface();
    IvarUsageMap M;


    ASTContext &Ctx = BR.getContext();

    // Iterate over the ivars.
    for (ObjCInterfaceDecl::ivar_iterator I=ID->ivar_begin(), E=ID->ivar_end();
            I!=E; ++I) {

        ObjCIvarDecl* ID = *I;

        // Ignore ivars that aren't private.
        if (ID->getAccessControl() != ObjCIvarDecl::Private)
            continue;

        // Skip IB Outlets.
        if (ID->getAttr<IBOutletAttr>())
            continue;

        M[ID] = Unused;
    }

    if (M.empty())
        return;

    // Now scan the methods for accesses.
    for (ObjCImplementationDecl::instmeth_iterator I = D->instmeth_begin(Ctx),
            E = D->instmeth_end(Ctx); I!=E; ++I)
        Scan(M, (*I)->getBody(Ctx));

    // Scan for @synthesized property methods that act as setters/getters
    // to an ivar.
    for (ObjCImplementationDecl::propimpl_iterator I = D->propimpl_begin(Ctx),
            E = D->propimpl_end(Ctx); I!=E; ++I)
        Scan(M, *I);

    // Find ivars that are unused.
    for (IvarUsageMap::iterator I = M.begin(), E = M.end(); I!=E; ++I)
        if (I->second == Unused) {

            std::ostringstream os;
            os << "Instance variable '" << I->first->getNameAsString()
               << "' in class '" << ID->getNameAsString()
               << "' is never used by the methods in its @implementation "
               "(although it may be used by category methods).";

            BR.EmitBasicReport("Unused instance variable", "Optimization",
                               os.str().c_str(), I->first->getLocation());
        }
}

static void checkObjCUnusedIvar(const ObjCImplementationDecl *D,
                                BugReporter &BR) {

  const ObjCInterfaceDecl *ID = D->getClassInterface();
  IvarUsageMap M;

  // Iterate over the ivars.
  for (ObjCInterfaceDecl::ivar_iterator I=ID->ivar_begin(),
        E=ID->ivar_end(); I!=E; ++I) {

    const ObjCIvarDecl *ID = *I;

    // Ignore ivars that...
    // (a) aren't private
    // (b) explicitly marked unused
    // (c) are iboutlets
    // (d) are unnamed bitfields
    if (ID->getAccessControl() != ObjCIvarDecl::Private ||
        ID->getAttr<UnusedAttr>() || ID->getAttr<IBOutletAttr>() ||
        ID->getAttr<IBOutletCollectionAttr>() ||
        ID->isUnnamedBitfield())
      continue;

    M[ID] = Unused;
  }

  if (M.empty())
    return;

  // Now scan the implementation declaration.
  Scan(M, D);

  // Any potentially unused ivars?
  bool hasUnused = false;
  for (IvarUsageMap::iterator I = M.begin(), E = M.end(); I!=E; ++I)
    if (I->second == Unused) {
      hasUnused = true;
      break;
    }

  if (!hasUnused)
    return;

  // We found some potentially unused ivars.  Scan the entire translation unit
  // for functions inside the @implementation that reference these ivars.
  // FIXME: In the future hopefully we can just use the lexical DeclContext
  // to go from the ObjCImplementationDecl to the lexically "nested"
  // C functions.
  SourceManager &SM = BR.getSourceManager();
  Scan(M, D->getDeclContext(), SM.getFileID(D->getLocation()), SM);

  // Find ivars that are unused.
  for (IvarUsageMap::iterator I = M.begin(), E = M.end(); I!=E; ++I)
    if (I->second == Unused) {
      std::string sbuf;
      llvm::raw_string_ostream os(sbuf);
      os << "Instance variable '" << *I->first << "' in class '" << *ID
         << "' is never used by the methods in its @implementation "
            "(although it may be used by category methods).";

      PathDiagnosticLocation L =
        PathDiagnosticLocation::create(I->first, BR.getSourceManager());
      BR.EmitBasicReport(D, "Unused instance variable", "Optimization",
                         os.str(), L);
    }
}