CommandLine.cpp

static HelpPrinter HiddenPrinter(true);

static cl::opt<HelpPrinter, true, parser<bool> >
HOp("help", cl::desc("Display available options (--help-hidden for more)"),
    cl::location(NormalPrinter), cl::ValueDisallowed);

static cl::opt<HelpPrinter, true, parser<bool> >
HHOp("help-hidden", cl::desc("Display all available options"),
     cl::location(HiddenPrinter), cl::Hidden, cl::ValueDisallowed);

static void (*OverrideVersionPrinter)() = 0;

namespace {
class VersionPrinter {
public:
  void print() {
        cout << "Low Level Virtual Machine (http://llvm.org/):\n";
        cout << "  " << PACKAGE_NAME << " version " << PACKAGE_VERSION;
#ifdef LLVM_VERSION_INFO
        cout << LLVM_VERSION_INFO;
#endif
        cout << "\n  ";
#ifndef __OPTIMIZE__
        cout << "DEBUG build";
#else
        cout << "Optimized build";
#endif
#ifndef NDEBUG
        cout << " with assertions";
#endif
        cout << ".\n";
  }
  void operator=(bool OptionWasSpecified) {
    if (OptionWasSpecified) {
      if (OverrideVersionPrinter == 0) {
        print();
        exit(1);
      } else {
        (*OverrideVersionPrinter)();
        exit(1);
      }
    }
  }
};
} // End anonymous namespace


// Define the --version option that prints out the LLVM version for the tool
static VersionPrinter VersionPrinterInstance;

static cl::opt<VersionPrinter, true, parser<bool> >
VersOp("version", cl::desc("Display the version of this program"),
    cl::location(VersionPrinterInstance), cl::ValueDisallowed);

// Utility function for printing the help message.
void cl::PrintHelpMessage() {
  // This looks weird, but it actually prints the help message. The
  // NormalPrinter variable is a HelpPrinter and the help gets printed when
  // its operator= is invoked. That's because the "normal" usages of the
  // help printer is to be assigned true/false depending on whether the
  // --help option was given or not. Since we're circumventing that we have
  // to make it look like --help was given, so we assign true.
  NormalPrinter = true;
}

/// Utility function for printing version number.
void cl::PrintVersionMessage() {
  VersionPrinterInstance.print();
}

void cl::SetVersionPrinter(void (*func)()) {
  OverrideVersionPrinter = func;
}