C++ (Cpp) Preprocessor::Diag示例

void PragmaRecorder::HandlePragma(clang::Preprocessor &PP,
                                  clang::PragmaIntroducerKind Introducer,
                                  clang::Token &FirstToken) {
  clang::Token &CurrentToken = FirstToken;
  std::string PragmaName, PragmaValue = "";
  // Pragma in ACC should be a name/value pair

  if (GetPragmaNameFromToken(FirstToken, PragmaName)) {
    // start parsing the value '(' PragmaValue ')', if we have one.
    const clang::Token* NextToken = &PP.LookAhead(0);

    if (NextToken->is(clang::tok::l_paren))
      PP.LexUnexpandedToken(CurrentToken);
    else
      goto end_parsing_pragma_value;

    NextToken = &PP.LookAhead(0);
    if (GetPragmaValueFromToken(*NextToken, PragmaValue)) {
      PP.Lex(CurrentToken);
    } else {
      PP.LexUnexpandedToken(CurrentToken);
      PP.Diag(NextToken->getLocation(),
              PP.getDiagnostics().getCustomDiagID(
                  clang::DiagnosticsEngine::Error,
                  "expected value after '#pragma %0('")) << PragmaName;
      return;
    }

    if (!NextToken->is(clang::tok::r_paren)) {
      NextToken = &PP.LookAhead(0);
      if (NextToken->is(clang::tok::r_paren)) {
        PP.LexUnexpandedToken(CurrentToken);
      } else {
        PP.LexUnexpandedToken(CurrentToken);
        PP.Diag(NextToken->getLocation(),
                PP.getDiagnostics().getCustomDiagID(
                    clang::DiagnosticsEngine::Error,
                    "missing ')' after '#pragma %0(%1'"))
            << PragmaName << PragmaValue;
        return;
      }
    }
  } else {
    PP.Diag(FirstToken.getLocation(),
            PP.getDiagnostics().getCustomDiagID(
                clang::DiagnosticsEngine::Error,
                "no pragma name or value"));
    return;
  }

 end_parsing_pragma_value:

  // PragmaValue may be an empty string.
  mPragmas->push_back(make_pair(PragmaName, PragmaValue));

  // Inform lex to eat the token
  PP.LexUnexpandedToken(CurrentToken);

  return;
}