C++ PragmaNamespace类代码示例

/// AddPragmaHandler - Add the specified pragma handler to the preprocessor.
/// If 'Namespace' is non-null, then it is a token required to exist on the
/// pragma line before the pragma string starts, e.g. "STDC" or "GCC".
void Preprocessor::AddPragmaHandler(const char *Namespace,
                                    PragmaHandler *Handler) {
  PragmaNamespace *InsertNS = PragmaHandlers;

  // If this is specified to be in a namespace, step down into it.
  if (Namespace) {
    IdentifierInfo *NSID = getIdentifierInfo(Namespace);

    // If there is already a pragma handler with the name of this namespace,
    // we either have an error (directive with the same name as a namespace) or
    // we already have the namespace to insert into.
    if (PragmaHandler *Existing = PragmaHandlers->FindHandler(NSID)) {
      InsertNS = Existing->getIfNamespace();
      assert(InsertNS != 0 && "Cannot have a pragma namespace and pragma"
             " handler with the same name!");
    } else {
      // Otherwise, this namespace doesn't exist yet, create and insert the
      // handler for it.
      InsertNS = new PragmaNamespace(NSID);
      PragmaHandlers->AddPragma(InsertNS);
    }
  }

  // Check to make sure we don't already have a pragma for this identifier.
  assert(!InsertNS->FindHandler(Handler->getName()) &&
         "Pragma handler already exists for this identifier!");
  InsertNS->AddPragma(Handler);
}

/// Ignore all pragmas, useful for modes such as -Eonly which would otherwise
/// warn about those pragmas being unknown.
void Preprocessor::IgnorePragmas() {
  AddPragmaHandler(new EmptyPragmaHandler());
  // Also ignore all pragmas in all namespaces created
  // in Preprocessor::RegisterBuiltinPragmas().
  AddPragmaHandler("GCC", new EmptyPragmaHandler());
  AddPragmaHandler("clang", new EmptyPragmaHandler());
  if (PragmaHandler *NS = PragmaHandlers->FindHandler("STDC")) {
    // Preprocessor::RegisterBuiltinPragmas() already registers
    // PragmaSTDC_UnknownHandler as the empty handler, so remove it first,
    // otherwise there will be an assert about a duplicate handler.
    PragmaNamespace *STDCNamespace = NS->getIfNamespace();
    assert(STDCNamespace &&
           "Invalid namespace, registered as a regular pragma handler!");
    if (PragmaHandler *Existing = STDCNamespace->FindHandler("", false)) {
      RemovePragmaHandler("STDC", Existing);
      delete Existing;
    }
  }
  AddPragmaHandler("STDC", new EmptyPragmaHandler());
}

/// RemovePragmaHandler - Remove the specific pragma handler from the
/// preprocessor. If \arg Namespace is non-null, then it should be the
/// namespace that \arg Handler was added to. It is an error to remove
/// a handler that has not been registered.
void Preprocessor::RemovePragmaHandler(const char *Namespace,
                                       PragmaHandler *Handler) {
  PragmaNamespace *NS = PragmaHandlers;

  // If this is specified to be in a namespace, step down into it.
  if (Namespace) {
    IdentifierInfo *NSID = getIdentifierInfo(Namespace);
    PragmaHandler *Existing = PragmaHandlers->FindHandler(NSID);
    assert(Existing && "Namespace containing handler does not exist!");

    NS = Existing->getIfNamespace();
    assert(NS && "Invalid namespace, registered as a regular pragma handler!");
  }

  NS->RemovePragmaHandler(Handler);

  // If this is a non-default namespace and it is now empty, remove
  // it.
  if (NS != PragmaHandlers && NS->IsEmpty())
    PragmaHandlers->RemovePragmaHandler(NS);
}

/// RemovePragmaHandler - Remove the specific pragma handler from the
/// preprocessor. If \arg Namespace is non-null, then it should be the
/// namespace that \arg Handler was added to. It is an error to remove
/// a handler that has not been registered.
void Preprocessor::RemovePragmaHandler(StringRef Namespace,
                                       PragmaHandler *Handler) {
  PragmaNamespace *NS = PragmaHandlers.get();

  // If this is specified to be in a namespace, step down into it.
  if (!Namespace.empty()) {
    PragmaHandler *Existing = PragmaHandlers->FindHandler(Namespace);
    assert(Existing && "Namespace containing handler does not exist!");

    NS = Existing->getIfNamespace();
    assert(NS && "Invalid namespace, registered as a regular pragma handler!");
  }

  NS->RemovePragmaHandler(Handler);

  // If this is a non-default namespace and it is now empty, remove it.
  if (NS != PragmaHandlers.get() && NS->IsEmpty()) {
    PragmaHandlers->RemovePragmaHandler(NS);
    delete NS;
  }
}