Initial checkin

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@278 91177308-0d34-0410-b5e6-96231b3b80d8

lib/Support/CommandLine.cpp

@@ -0,0 +1,399 @@
+//===-- CommandLine.cpp - Command line parser implementation --------------===//
+//
+// This class implements a command line argument processor that is useful when
+// creating a tool.  It provides a simple, minimalistic interface that is easily
+// extensible and supports nonlocal (library) command line options.
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/Tools/CommandLine.h"
+#include "llvm/Tools/STLExtras.h"
+#include <vector>
+#include <algorithm>
+#include <map>
+#include <set>
+using namespace cl;
+
+// Return the global command line option vector.  Making it a function scoped
+// static ensures that it will be initialized before its first use correctly.
+//
+static map<string, Option*> &getOpts() {
+  static map<string,Option*> CommandLineOptions;
+  return CommandLineOptions;
+}
+
+static void AddArgument(const string &ArgName, Option *Opt) {
+  if (getOpts().find(ArgName) != getOpts().end()) {
+    cerr << "CommandLine Error: Argument '" << ArgName
+	 << "' specified more than once!\n";
+  } else {
+    getOpts()[ArgName] = Opt;  // Add argument to the argument map!
+  }
+}
+
+static const char *ProgramName = 0;
+static const char *ProgramOverview = 0;
+
+void cl::ParseCommandLineOptions(int &argc, char **argv,
+				 const char *Overview = 0) {
+  ProgramName = argv[0];  // Save this away safe and snug
+  ProgramOverview = Overview;
+  bool ErrorParsing = false;
+
+  // Loop over all of the arguments... processing them.
+  for (int i = 1; i < argc; ++i) {
+    Option *Handler = 0;
+    const char *Value = "";
+    const char *ArgName = "";
+    if (argv[i][0] != '-') {   // Unnamed argument?
+      Handler = getOpts()[""];
+      Value = argv[i];
+    } else {               // We start with a - or --, eat dashes
+      ArgName = argv[i]+1;
+      while (*ArgName == '-') ++ArgName;  // Eat leading dashes
+
+      const char *ArgNameEnd = ArgName;
+      while (*ArgNameEnd && *ArgNameEnd != '=') ++ArgNameEnd; // Scan till end
+
+      Value = ArgNameEnd;
+      if (*Value)           // If we have an equals sign...
+	++Value;            // Advance to value...
+
+      if (*ArgName != 0) {
+	string ArgNameStr(ArgName, ArgNameEnd); // Extract arg name part
+	Handler = getOpts()[ArgNameStr];
+      }
+    }
+
+    if (Handler == 0) {
+      cerr << "Unknown command line argument '" << argv[i] << "'.  Try: "
+	   << argv[0] << " --help\n'";
+      ErrorParsing = true;
+      continue;
+    }
+
+    // Enforce value requirements
+    switch (Handler->Flags & ValueMask) {
+    case ValueRequired:
+      if (Value == 0 || *Value == 0) {  // No value specified?
+	if (i+1 < argc) {     // Steal the next argument, like for '-o filename'
+	  Value = argv[++i];
+	} else {
+	  ErrorParsing = Handler->error(" requires a value!");
+	  continue;
+	}
+      }
+      break;
+    case ValueDisallowed:
+      if (*Value != 0) {
+	ErrorParsing = Handler->error(" does not allow a value! '" + 
+				      string(Value) + "' specified.");
+	continue;
+      }
+      break;
+    case Optional: break;
+    default: cerr << "Bad ValueMask flag! CommandLine usage error!\n"; abort();
+    }
+
+    // Run the handler now!
+    ErrorParsing |= Handler->addOccurance(ArgName, Value);
+  }
+
+  // TODO: loop over args and make sure all required args are specified!
+
+  // Free all of the memory allocated to the vector.  Command line options may
+  // only be processed once!
+  getOpts().clear();
+
+  // If we had an error processing our arguments, don't let the program execute
+  if (ErrorParsing) exit(1);
+}
+
+//===----------------------------------------------------------------------===//
+// Option Base class implementation
+//
+Option::Option(const char *argStr, const char *helpStr, int flags)
+  : NumOccurances(0), ArgStr(argStr), HelpStr(helpStr), Flags(flags) {
+  AddArgument(ArgStr, this);
+}
+
+bool Option::error(string Message, const char *ArgName = 0) {
+  if (ArgName == 0) ArgName = ArgStr;
+  cerr << "-" << ArgName << " option" << Message << endl;
+  return true;
+}
+
+bool Option::addOccurance(const char *ArgName, const string &Value) {
+  NumOccurances++;   // Increment the number of times we have been seen
+
+  switch (Flags & OccurancesMask) {
+  case Optional:
+    if (NumOccurances > 1)
+      return error(": may only occur zero or one times!", ArgName);
+    break;
+  case Required:
+    if (NumOccurances > 1)
+      return error(": must occur exactly one time!", ArgName);
+    // Fall through
+  case OneOrMore:
+  case ZeroOrMore: break;
+  default: return error(": bad num occurances flag value!");
+  }
+
+  return handleOccurance(ArgName, Value);
+}
+
+// Return the width of the option tag for printing...
+unsigned Option::getOptionWidth() const {
+  return std::strlen(ArgStr)+6;
+}
+
+void Option::printOptionInfo(unsigned GlobalWidth) const {
+  unsigned L = std::strlen(ArgStr);
+  if (L == 0) return;  // Don't print the empty arg like this!
+  cerr << "  -" << ArgStr << string(GlobalWidth-L-6, ' ') << " - "
+       << HelpStr << endl;
+}
+
+
+//===----------------------------------------------------------------------===//
+// Boolean/flag command line option implementation
+//
+
+bool Flag::handleOccurance(const char *ArgName, const string &Arg) {
+  if (Arg == "" || Arg == "true" || Arg == "TRUE" || Arg == "True" || 
+      Arg == "1") {
+    Value = true;
+  } else if (Arg == "false" || Arg == "FALSE" || Arg == "False" || Arg == "0") {
+    Value = false;
+  } else {
+    return error(": '" + Arg + "' is invalid value for boolean argument! Try 0 or 1");
+  }
+
+  return false;
+}
+
+//===----------------------------------------------------------------------===//
+// Integer valued command line option implementation
+//
+bool Int::handleOccurance(const char *ArgName, const string &Arg) {
+  const char *ArgStart = Arg.c_str();
+  char *End;
+  Value = (int)strtol(ArgStart, &End, 0);
+  if (*End != 0) 
+    return error(": '" + Arg + "' value invalid for integer argument!");
+  return false;  
+}
+
+//===----------------------------------------------------------------------===//
+// String valued command line option implementation
+//
+bool String::handleOccurance(const char *ArgName, const string &Arg) {
+  Value = Arg;
+  return false;
+}
+
+//===----------------------------------------------------------------------===//
+// Enum valued command line option implementation
+//
+void EnumBase::processValues(va_list Vals) {
+  while (const char *EnumName = va_arg(Vals, const char *)) {
+    int EnumVal = va_arg(Vals, int);
+    const char *EnumDesc = va_arg(Vals, const char *);
+    ValueMap.push_back(make_pair(EnumName,           // Add value to value map
+				 make_pair(EnumVal, EnumDesc)));
+  }
+}
+
+// registerArgs - notify the system about these new arguments
+void EnumBase::registerArgs() {
+  for (unsigned i = 0; i < ValueMap.size(); ++i)
+    AddArgument(ValueMap[i].first, this);
+}
+
+const char *EnumBase::getArgName(int ID) const {
+  for (unsigned i = 0; i < ValueMap.size(); ++i)
+    if (ID == ValueMap[i].second.first) return ValueMap[i].first;
+  return "";
+}
+const char *EnumBase::getArgDescription(int ID) const {
+  for (unsigned i = 0; i < ValueMap.size(); ++i)
+    if (ID == ValueMap[i].second.first) return ValueMap[i].second.second;
+  return "";
+}
+
+
+
+bool EnumValueBase::handleOccurance(const char *ArgName, const string &Arg) {
+  unsigned i;
+  for (i = 0; i < ValueMap.size(); ++i)
+    if (ValueMap[i].first == Arg) break;
+  if (i == ValueMap.size())
+    return error(": unrecognized alternative '"+Arg+"'!");
+  Value = ValueMap[i].second.first;
+  return false;
+}
+
+// Return the width of the option tag for printing...
+unsigned EnumValueBase::getOptionWidth() const {
+  unsigned BaseSize = Option::getOptionWidth();
+  for (unsigned i = 0; i < ValueMap.size(); ++i)
+    BaseSize = max(BaseSize, std::strlen(ValueMap[i].first)+8);
+  return BaseSize;
+}
+
+// printOptionInfo - Print out information about this option.  The 
+// to-be-maintained width is specified.
+//
+void EnumValueBase::printOptionInfo(unsigned GlobalWidth) const {
+  Option::printOptionInfo(GlobalWidth);
+  for (unsigned i = 0; i < ValueMap.size(); ++i) {
+    unsigned NumSpaces = GlobalWidth-strlen(ValueMap[i].first)-8;
+    cerr << "    =" << ValueMap[i].first << string(NumSpaces, ' ') << " - "
+	 << ValueMap[i].second.second;
+
+    if (i == 0) cerr << " (default)";
+    cerr << endl;
+  }
+}
+
+//===----------------------------------------------------------------------===//
+// Enum flags command line option implementation
+//
+
+bool EnumFlagsBase::handleOccurance(const char *ArgName, const string &Arg) {
+  return EnumValueBase::handleOccurance("", ArgName);
+}
+
+unsigned EnumFlagsBase::getOptionWidth() const {
+  unsigned BaseSize = 0;
+  for (unsigned i = 0; i < ValueMap.size(); ++i)
+    BaseSize = max(BaseSize, std::strlen(ValueMap[i].first)+6);
+  return BaseSize;
+}
+
+void EnumFlagsBase::printOptionInfo(unsigned GlobalWidth) const {
+  for (unsigned i = 0; i < ValueMap.size(); ++i) {
+    unsigned L = std::strlen(ValueMap[i].first);
+    cerr << "  -" << ValueMap[i].first << string(GlobalWidth-L-6, ' ') << " - "
+	 << ValueMap[i].second.second;
+    if (i == 0) cerr << " (default)";
+    cerr << endl;
+  }
+}
+
+
+//===----------------------------------------------------------------------===//
+// Enum list command line option implementation
+//
+
+bool EnumListBase::handleOccurance(const char *ArgName, const string &Arg) {
+  unsigned i;
+  for (i = 0; i < ValueMap.size(); ++i)
+    if (ValueMap[i].first == string(ArgName)) break;
+  if (i == ValueMap.size())
+    return error(": CommandLine INTERNAL ERROR", ArgName);
+  Values.push_back(ValueMap[i].second.first);
+  return false;
+}
+
+// Return the width of the option tag for printing...
+unsigned EnumListBase::getOptionWidth() const {
+  unsigned BaseSize = 0;
+  for (unsigned i = 0; i < ValueMap.size(); ++i)
+    BaseSize = max(BaseSize, std::strlen(ValueMap[i].first)+6);
+  return BaseSize;
+}
+
+
+// printOptionInfo - Print out information about this option.  The 
+// to-be-maintained width is specified.
+//
+void EnumListBase::printOptionInfo(unsigned GlobalWidth) const {
+  for (unsigned i = 0; i < ValueMap.size(); ++i) {
+    unsigned L = std::strlen(ValueMap[i].first);
+    cerr << "  -" << ValueMap[i].first << string(GlobalWidth-L-6, ' ') << " - "
+	 << ValueMap[i].second.second << endl;
+  }
+}
+
+
+//===----------------------------------------------------------------------===//
+// Help option... always automatically provided.
+//
+namespace {
+
+// isHidden/isReallyHidden - Predicates to be used to filter down arg lists.
+inline bool isHidden(pair<string, Option *> &OptPair) {
+  return (OptPair.second->Flags & HiddenMask) == Hidden;
+}
+inline bool isReallyHidden(pair<string, Option *> &OptPair) {
+  return (OptPair.second->Flags & HiddenMask) == ReallyHidden;
+}
+
+class Help : public Option {
+  unsigned MaxArgLen;
+  const Option *EmptyArg;
+  const bool ShowHidden;
+
+  virtual bool handleOccurance(const char *ArgName, const string &Arg) {
+    // Copy Options into a vector so we can sort them as we like...
+    vector<pair<string, Option*> > Options;
+    copy(getOpts().begin(), getOpts().end(), back_inserter(Options));
+
+    // Eliminate Hidden or ReallyHidden arguments, depending on ShowHidden
+    Options.erase(remove_if(Options.begin(), Options.end(), 
+			    ptr_fun(ShowHidden ? isReallyHidden : isHidden)),
+		  Options.end());
+
+    // Eliminate duplicate entries in table (from enum flags options, f.e.)
+    set<Option*> OptionSet;
+    for (unsigned i = 0; i < Options.size(); )
+      if (OptionSet.count(Options[i].second) == 0)
+	OptionSet.insert(Options[i++].second); // Add to set
+      else
+	Options.erase(Options.begin()+i);      // Erase duplicate
+
+
+    if (ProgramOverview)
+      cerr << "OVERVIEW:" << ProgramOverview << endl;
+    // TODO: Sort options by some criteria
+
+    cerr << "USAGE: " << ProgramName << " [options]\n\n";
+    // TODO: print usage nicer
+
+    // Compute the maximum argument length...
+    MaxArgLen = 0;
+    for_each(Options.begin(), Options.end(),
+	     bind_obj(this, &Help::getMaxArgLen));
+
+    cerr << "OPTIONS:\n";
+    for_each(Options.begin(), Options.end(), 
+	     bind_obj(this, &Help::printOption));
+
+    return true;  // Displaying help is cause to terminate the program
+  }
+
+  void getMaxArgLen(pair<string, Option *> OptPair) {
+    const Option *Opt = OptPair.second;
+    if (Opt->ArgStr[0] == 0) EmptyArg = Opt; // Capture the empty arg if exists
+    MaxArgLen = max(MaxArgLen, Opt->getOptionWidth());
+  }
+
+  void printOption(pair<string, Option *> OptPair) {
+    const Option *Opt = OptPair.second;
+    Opt->printOptionInfo(MaxArgLen);
+  }
+
+public:
+  inline Help(const char *ArgVal, const char *HelpVal, bool showHidden)
+    : Option(ArgVal, HelpVal, showHidden ? Hidden : 0), ShowHidden(showHidden) {
+    EmptyArg = 0;
+  }
+};
+
+Help HelpOp("help", "display available options"
+	    " (-help-hidden for more)", false);
+Help HelpHiddenOpt("help-hidden", "display all available options", true);
+
+} // End anonymous namespace

support/lib/Support/CommandLine.cpp

@@ -0,0 +1,399 @@
+//===-- CommandLine.cpp - Command line parser implementation --------------===//
+//
+// This class implements a command line argument processor that is useful when
+// creating a tool.  It provides a simple, minimalistic interface that is easily
+// extensible and supports nonlocal (library) command line options.
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/Tools/CommandLine.h"
+#include "llvm/Tools/STLExtras.h"
+#include <vector>
+#include <algorithm>
+#include <map>
+#include <set>
+using namespace cl;
+
+// Return the global command line option vector.  Making it a function scoped
+// static ensures that it will be initialized before its first use correctly.
+//
+static map<string, Option*> &getOpts() {
+  static map<string,Option*> CommandLineOptions;
+  return CommandLineOptions;
+}
+
+static void AddArgument(const string &ArgName, Option *Opt) {
+  if (getOpts().find(ArgName) != getOpts().end()) {
+    cerr << "CommandLine Error: Argument '" << ArgName
+	 << "' specified more than once!\n";
+  } else {
+    getOpts()[ArgName] = Opt;  // Add argument to the argument map!
+  }
+}
+
+static const char *ProgramName = 0;
+static const char *ProgramOverview = 0;
+
+void cl::ParseCommandLineOptions(int &argc, char **argv,
+				 const char *Overview = 0) {
+  ProgramName = argv[0];  // Save this away safe and snug
+  ProgramOverview = Overview;
+  bool ErrorParsing = false;
+
+  // Loop over all of the arguments... processing them.
+  for (int i = 1; i < argc; ++i) {
+    Option *Handler = 0;
+    const char *Value = "";
+    const char *ArgName = "";
+    if (argv[i][0] != '-') {   // Unnamed argument?
+      Handler = getOpts()[""];
+      Value = argv[i];
+    } else {               // We start with a - or --, eat dashes
+      ArgName = argv[i]+1;
+      while (*ArgName == '-') ++ArgName;  // Eat leading dashes
+
+      const char *ArgNameEnd = ArgName;
+      while (*ArgNameEnd && *ArgNameEnd != '=') ++ArgNameEnd; // Scan till end
+
+      Value = ArgNameEnd;
+      if (*Value)           // If we have an equals sign...
+	++Value;            // Advance to value...
+
+      if (*ArgName != 0) {
+	string ArgNameStr(ArgName, ArgNameEnd); // Extract arg name part
+	Handler = getOpts()[ArgNameStr];
+      }
+    }
+
+    if (Handler == 0) {
+      cerr << "Unknown command line argument '" << argv[i] << "'.  Try: "
+	   << argv[0] << " --help\n'";
+      ErrorParsing = true;
+      continue;
+    }
+
+    // Enforce value requirements
+    switch (Handler->Flags & ValueMask) {
+    case ValueRequired:
+      if (Value == 0 || *Value == 0) {  // No value specified?
+	if (i+1 < argc) {     // Steal the next argument, like for '-o filename'
+	  Value = argv[++i];
+	} else {
+	  ErrorParsing = Handler->error(" requires a value!");
+	  continue;
+	}
+      }
+      break;
+    case ValueDisallowed:
+      if (*Value != 0) {
+	ErrorParsing = Handler->error(" does not allow a value! '" + 
+				      string(Value) + "' specified.");
+	continue;
+      }
+      break;
+    case Optional: break;
+    default: cerr << "Bad ValueMask flag! CommandLine usage error!\n"; abort();
+    }
+
+    // Run the handler now!
+    ErrorParsing |= Handler->addOccurance(ArgName, Value);
+  }
+
+  // TODO: loop over args and make sure all required args are specified!
+
+  // Free all of the memory allocated to the vector.  Command line options may
+  // only be processed once!
+  getOpts().clear();
+
+  // If we had an error processing our arguments, don't let the program execute
+  if (ErrorParsing) exit(1);
+}
+
+//===----------------------------------------------------------------------===//
+// Option Base class implementation
+//
+Option::Option(const char *argStr, const char *helpStr, int flags)
+  : NumOccurances(0), ArgStr(argStr), HelpStr(helpStr), Flags(flags) {
+  AddArgument(ArgStr, this);
+}
+
+bool Option::error(string Message, const char *ArgName = 0) {
+  if (ArgName == 0) ArgName = ArgStr;
+  cerr << "-" << ArgName << " option" << Message << endl;
+  return true;
+}
+
+bool Option::addOccurance(const char *ArgName, const string &Value) {
+  NumOccurances++;   // Increment the number of times we have been seen
+
+  switch (Flags & OccurancesMask) {
+  case Optional:
+    if (NumOccurances > 1)
+      return error(": may only occur zero or one times!", ArgName);
+    break;
+  case Required:
+    if (NumOccurances > 1)
+      return error(": must occur exactly one time!", ArgName);
+    // Fall through
+  case OneOrMore:
+  case ZeroOrMore: break;
+  default: return error(": bad num occurances flag value!");
+  }
+
+  return handleOccurance(ArgName, Value);
+}
+
+// Return the width of the option tag for printing...
+unsigned Option::getOptionWidth() const {
+  return std::strlen(ArgStr)+6;
+}
+
+void Option::printOptionInfo(unsigned GlobalWidth) const {
+  unsigned L = std::strlen(ArgStr);
+  if (L == 0) return;  // Don't print the empty arg like this!
+  cerr << "  -" << ArgStr << string(GlobalWidth-L-6, ' ') << " - "
+       << HelpStr << endl;
+}
+
+
+//===----------------------------------------------------------------------===//
+// Boolean/flag command line option implementation
+//
+
+bool Flag::handleOccurance(const char *ArgName, const string &Arg) {
+  if (Arg == "" || Arg == "true" || Arg == "TRUE" || Arg == "True" || 
+      Arg == "1") {
+    Value = true;
+  } else if (Arg == "false" || Arg == "FALSE" || Arg == "False" || Arg == "0") {
+    Value = false;
+  } else {
+    return error(": '" + Arg + "' is invalid value for boolean argument! Try 0 or 1");
+  }
+
+  return false;
+}
+
+//===----------------------------------------------------------------------===//
+// Integer valued command line option implementation
+//
+bool Int::handleOccurance(const char *ArgName, const string &Arg) {
+  const char *ArgStart = Arg.c_str();
+  char *End;
+  Value = (int)strtol(ArgStart, &End, 0);
+  if (*End != 0) 
+    return error(": '" + Arg + "' value invalid for integer argument!");
+  return false;  
+}
+
+//===----------------------------------------------------------------------===//
+// String valued command line option implementation
+//
+bool String::handleOccurance(const char *ArgName, const string &Arg) {
+  Value = Arg;
+  return false;
+}
+
+//===----------------------------------------------------------------------===//
+// Enum valued command line option implementation
+//
+void EnumBase::processValues(va_list Vals) {
+  while (const char *EnumName = va_arg(Vals, const char *)) {
+    int EnumVal = va_arg(Vals, int);
+    const char *EnumDesc = va_arg(Vals, const char *);
+    ValueMap.push_back(make_pair(EnumName,           // Add value to value map
+				 make_pair(EnumVal, EnumDesc)));
+  }
+}
+
+// registerArgs - notify the system about these new arguments
+void EnumBase::registerArgs() {
+  for (unsigned i = 0; i < ValueMap.size(); ++i)
+    AddArgument(ValueMap[i].first, this);
+}
+
+const char *EnumBase::getArgName(int ID) const {
+  for (unsigned i = 0; i < ValueMap.size(); ++i)
+    if (ID == ValueMap[i].second.first) return ValueMap[i].first;
+  return "";
+}
+const char *EnumBase::getArgDescription(int ID) const {
+  for (unsigned i = 0; i < ValueMap.size(); ++i)
+    if (ID == ValueMap[i].second.first) return ValueMap[i].second.second;
+  return "";
+}
+
+
+
+bool EnumValueBase::handleOccurance(const char *ArgName, const string &Arg) {
+  unsigned i;
+  for (i = 0; i < ValueMap.size(); ++i)
+    if (ValueMap[i].first == Arg) break;
+  if (i == ValueMap.size())
+    return error(": unrecognized alternative '"+Arg+"'!");
+  Value = ValueMap[i].second.first;
+  return false;
+}
+
+// Return the width of the option tag for printing...
+unsigned EnumValueBase::getOptionWidth() const {
+  unsigned BaseSize = Option::getOptionWidth();
+  for (unsigned i = 0; i < ValueMap.size(); ++i)
+    BaseSize = max(BaseSize, std::strlen(ValueMap[i].first)+8);
+  return BaseSize;
+}
+
+// printOptionInfo - Print out information about this option.  The 
+// to-be-maintained width is specified.
+//
+void EnumValueBase::printOptionInfo(unsigned GlobalWidth) const {
+  Option::printOptionInfo(GlobalWidth);
+  for (unsigned i = 0; i < ValueMap.size(); ++i) {
+    unsigned NumSpaces = GlobalWidth-strlen(ValueMap[i].first)-8;
+    cerr << "    =" << ValueMap[i].first << string(NumSpaces, ' ') << " - "
+	 << ValueMap[i].second.second;
+
+    if (i == 0) cerr << " (default)";
+    cerr << endl;
+  }
+}
+
+//===----------------------------------------------------------------------===//
+// Enum flags command line option implementation
+//
+
+bool EnumFlagsBase::handleOccurance(const char *ArgName, const string &Arg) {
+  return EnumValueBase::handleOccurance("", ArgName);
+}
+
+unsigned EnumFlagsBase::getOptionWidth() const {
+  unsigned BaseSize = 0;
+  for (unsigned i = 0; i < ValueMap.size(); ++i)
+    BaseSize = max(BaseSize, std::strlen(ValueMap[i].first)+6);
+  return BaseSize;
+}
+
+void EnumFlagsBase::printOptionInfo(unsigned GlobalWidth) const {
+  for (unsigned i = 0; i < ValueMap.size(); ++i) {
+    unsigned L = std::strlen(ValueMap[i].first);
+    cerr << "  -" << ValueMap[i].first << string(GlobalWidth-L-6, ' ') << " - "
+	 << ValueMap[i].second.second;
+    if (i == 0) cerr << " (default)";
+    cerr << endl;
+  }
+}
+
+
+//===----------------------------------------------------------------------===//
+// Enum list command line option implementation
+//
+
+bool EnumListBase::handleOccurance(const char *ArgName, const string &Arg) {
+  unsigned i;
+  for (i = 0; i < ValueMap.size(); ++i)
+    if (ValueMap[i].first == string(ArgName)) break;
+  if (i == ValueMap.size())
+    return error(": CommandLine INTERNAL ERROR", ArgName);
+  Values.push_back(ValueMap[i].second.first);
+  return false;
+}
+
+// Return the width of the option tag for printing...
+unsigned EnumListBase::getOptionWidth() const {
+  unsigned BaseSize = 0;
+  for (unsigned i = 0; i < ValueMap.size(); ++i)
+    BaseSize = max(BaseSize, std::strlen(ValueMap[i].first)+6);
+  return BaseSize;
+}
+
+
+// printOptionInfo - Print out information about this option.  The 
+// to-be-maintained width is specified.
+//
+void EnumListBase::printOptionInfo(unsigned GlobalWidth) const {
+  for (unsigned i = 0; i < ValueMap.size(); ++i) {
+    unsigned L = std::strlen(ValueMap[i].first);
+    cerr << "  -" << ValueMap[i].first << string(GlobalWidth-L-6, ' ') << " - "
+	 << ValueMap[i].second.second << endl;
+  }
+}
+
+
+//===----------------------------------------------------------------------===//
+// Help option... always automatically provided.
+//
+namespace {
+
+// isHidden/isReallyHidden - Predicates to be used to filter down arg lists.
+inline bool isHidden(pair<string, Option *> &OptPair) {
+  return (OptPair.second->Flags & HiddenMask) == Hidden;
+}
+inline bool isReallyHidden(pair<string, Option *> &OptPair) {
+  return (OptPair.second->Flags & HiddenMask) == ReallyHidden;
+}
+
+class Help : public Option {
+  unsigned MaxArgLen;
+  const Option *EmptyArg;
+  const bool ShowHidden;
+
+  virtual bool handleOccurance(const char *ArgName, const string &Arg) {
+    // Copy Options into a vector so we can sort them as we like...
+    vector<pair<string, Option*> > Options;
+    copy(getOpts().begin(), getOpts().end(), back_inserter(Options));
+
+    // Eliminate Hidden or ReallyHidden arguments, depending on ShowHidden
+    Options.erase(remove_if(Options.begin(), Options.end(), 
+			    ptr_fun(ShowHidden ? isReallyHidden : isHidden)),
+		  Options.end());
+
+    // Eliminate duplicate entries in table (from enum flags options, f.e.)
+    set<Option*> OptionSet;
+    for (unsigned i = 0; i < Options.size(); )
+      if (OptionSet.count(Options[i].second) == 0)
+	OptionSet.insert(Options[i++].second); // Add to set
+      else
+	Options.erase(Options.begin()+i);      // Erase duplicate
+
+
+    if (ProgramOverview)
+      cerr << "OVERVIEW:" << ProgramOverview << endl;
+    // TODO: Sort options by some criteria
+
+    cerr << "USAGE: " << ProgramName << " [options]\n\n";
+    // TODO: print usage nicer
+
+    // Compute the maximum argument length...
+    MaxArgLen = 0;
+    for_each(Options.begin(), Options.end(),
+	     bind_obj(this, &Help::getMaxArgLen));
+
+    cerr << "OPTIONS:\n";
+    for_each(Options.begin(), Options.end(), 
+	     bind_obj(this, &Help::printOption));
+
+    return true;  // Displaying help is cause to terminate the program
+  }
+
+  void getMaxArgLen(pair<string, Option *> OptPair) {
+    const Option *Opt = OptPair.second;
+    if (Opt->ArgStr[0] == 0) EmptyArg = Opt; // Capture the empty arg if exists
+    MaxArgLen = max(MaxArgLen, Opt->getOptionWidth());
+  }
+
+  void printOption(pair<string, Option *> OptPair) {
+    const Option *Opt = OptPair.second;
+    Opt->printOptionInfo(MaxArgLen);
+  }
+
+public:
+  inline Help(const char *ArgVal, const char *HelpVal, bool showHidden)
+    : Option(ArgVal, HelpVal, showHidden ? Hidden : 0), ShowHidden(showHidden) {
+    EmptyArg = 0;
+  }
+};
+
+Help HelpOp("help", "display available options"
+	    " (-help-hidden for more)", false);
+Help HelpHiddenOpt("help-hidden", "display all available options", true);
+
+} // End anonymous namespace