Initial checkin of the LLVM Source-Level Debugger. This is incomplete, but

a good start.  The status is documented in docs/SourceLevelDebugging.html


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@10687 91177308-0d34-0410-b5e6-96231b3b80d8

6 files changed, 1546 insertions, 0 deletions

diff --git a/tools/llvm-db/CLICommand.h b/tools/llvm-db/CLICommand.h
new file mode 100644
index 0000000000..25451e747f
--- /dev/null
+++ b/tools/llvm-db/CLICommand.h
@@ -0,0 +1,110 @@
+//===- CLICommand.h - Classes used to represent commands --------*- C++ -*-===//
+// 
+//                     The LLVM Compiler Infrastructure
+//
+// This file was developed by the LLVM research group and is distributed under
+// the University of Illinois Open Source License. See LICENSE.TXT for details.
+// 
+//===----------------------------------------------------------------------===//
+//
+// This file defines a small class hierarchy used to represent the various types
+// of commands in the CLI debugger front-end.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef CLICOMMAND_H
+#define CLICOMMAND_H
+
+#include <string>
+#include <vector>
+
+namespace llvm {
+  class CLIDebugger;
+
+  /// CLICommand - Base class of the hierarchy, used to provide the abstract
+  /// interface common to all commands.
+  ///
+  class CLICommand {
+    /// ShortHelp, LongHelp - The short and long helps strings printed for the
+    /// command.  The ShortHelp string should be a single line of text without a
+    /// newline.  The LongHelp string should be a full description with
+    /// terminating newline.
+    std::string ShortHelp, LongHelp;
+
+    /// RefCount - This contains the number of entries in the CLIDebugger
+    /// CommandTable that points to this command.
+    unsigned RefCount;
+
+    /// OptionNames - This contains a list of names for the option.  Keeping
+    /// track of this is done just to make the help output more helpful.
+    ///
+    std::vector<std::string> OptionNames;
+  public:
+    CLICommand(const std::string &SH, const std::string &LH)
+      : ShortHelp(SH), LongHelp(LH), RefCount(0) {}
+
+    virtual ~CLICommand() {}
+
+    /// addRef/dropRef - Implement a simple reference counting scheme to make
+    /// sure we delete commands that are no longer used.
+    void addRef() { ++RefCount; }
+    void dropRef() {
+      if (--RefCount == 0) delete this;
+    }
+
+    /// getPrimaryOptionName - Return the first name the option was added under.
+    /// This is the name we report for the option in the help output.
+    std::string getPrimaryOptionName() const {
+      return OptionNames.empty() ? "" : OptionNames[0];
+    }
+
+    /// getOptionName - Return all of the names the option is registered as.
+    ///
+    const std::vector<std::string> &getOptionNames() const {
+      return OptionNames;
+    }
+
+    /// addOptionName - Add a name that this option is known as.
+    ///
+    void addOptionName(const std::string &Name) {
+      OptionNames.push_back(Name);
+    }
+
+    /// removeOptionName - Eliminate one of the names for this option.
+    ///
+    void removeOptionName(const std::string &Name) {
+      unsigned i = 0; 
+      for (; OptionNames[i] != Name; ++i)
+        assert(i+1 < OptionNames.size() && "Didn't find option name!");
+      OptionNames.erase(OptionNames.begin()+i);
+    }
+
+
+    /// getShortHelp - Return the short help string for this command.
+    ///
+    const std::string &getShortHelp() { return ShortHelp; }
+
+    /// getLongHelp - Return the long help string for this command, if it
+    /// exists.
+    const std::string &getLongHelp() { return LongHelp; }
+
+    virtual void runCommand(CLIDebugger &D, std::string &Arguments) = 0;
+  };
+
+  /// BuiltinCLICommand - This class represents commands that are built directly
+  /// into the debugger.
+  class BuiltinCLICommand : public CLICommand {
+    // Impl - Pointer to the method that implements the command
+    void (CLIDebugger::*Impl)(std::string&);
+  public:
+    BuiltinCLICommand(const std::string &ShortHelp, const std::string &LongHelp,
+                      void (CLIDebugger::*impl)(std::string&))
+      : CLICommand(ShortHelp, LongHelp), Impl(impl) {}
+    
+    void runCommand(CLIDebugger &D, std::string &Arguments) {
+      (D.*Impl)(Arguments);
+    }
+  };
+}
+
+#endif
diff --git a/tools/llvm-db/CLIDebugger.cpp b/tools/llvm-db/CLIDebugger.cpp
new file mode 100644
index 0000000000..2b3937a075
--- /dev/null
+++ b/tools/llvm-db/CLIDebugger.cpp
@@ -0,0 +1,285 @@
+//===-- CLIDebugger.cpp - Command Line Interface to the Debugger ----------===//
+// 
+//                     The LLVM Compiler Infrastructure
+//
+// This file was developed by the LLVM research group and is distributed under
+// the University of Illinois Open Source License. See LICENSE.TXT for details.
+// 
+//===----------------------------------------------------------------------===//
+// 
+// This file contains the main implementation of the Command Line Interface to
+// the debugger.
+//
+//===----------------------------------------------------------------------===//
+
+#include "CLIDebugger.h"
+#include "CLICommand.h"
+#include "llvm/Debugger/SourceFile.h"
+#include "Support/StringExtras.h"
+#include <iostream>
+using namespace llvm;
+
+/// CLIDebugger constructor - This initializes the debugger to its default
+/// state, and initializes the command table.
+///
+CLIDebugger::CLIDebugger()
+  : TheProgramInfo(0), TheRuntimeInfo(0), Prompt("(llvm-db) "), ListSize(10) {
+  // Initialize instance variables
+  CurrentFile = 0;
+  LineListedStart = 1;
+  LineListedEnd = 1;
+  LastCurrentFrame = 0;
+  CurrentLanguage = 0;
+
+  CLICommand *C;
+  //===--------------------------------------------------------------------===//
+  // Program startup and shutdown options
+  //
+  addCommand("file", new BuiltinCLICommand(
+    "Use specified file as the program to be debugged",
+    "The debugger looks in the current directory and the program $PATH for the"
+    " specified LLVM program.  It then unloads the currently loaded program and"
+    " loads the specified program.\n",
+    &CLIDebugger::fileCommand));
+
+  addCommand("create", new BuiltinCLICommand(
+    "Start the current program, stopping execution in main",
+    "This command creates an instance of the current program, but stops"
+    " execution immediately.",
+    &CLIDebugger::createCommand));
+
+  addCommand("kill", new BuiltinCLICommand(
+    "Kills the execution of the current program being debugged", "",
+    &CLIDebugger::killCommand));
+
+  addCommand("quit", new BuiltinCLICommand(
+    "Exit the debugger", "",
+    &CLIDebugger::quitCommand));
+
+  //===--------------------------------------------------------------------===//
+  // Program execution commands
+  //
+  addCommand("run", C = new BuiltinCLICommand(
+    "Start the program running from the beginning", "",
+    &CLIDebugger::runCommand));
+  addCommand("r", C);
+
+  addCommand("cont", C = new BuiltinCLICommand(
+    "Continue program being debugged until the next stop point", "",
+    &CLIDebugger::contCommand));
+  addCommand("c", C); addCommand("fg", C);
+
+  addCommand("step", C = new BuiltinCLICommand(
+    "Step program until it reaches a new source line", "",
+    &CLIDebugger::stepCommand));
+  addCommand("s", C);
+
+  addCommand("next", C = new BuiltinCLICommand(
+    "Step program until it reaches a new source line, stepping over calls", "",
+    &CLIDebugger::nextCommand));
+  addCommand("n", C); 
+
+  addCommand("finish", new BuiltinCLICommand(
+    "Execute until the selected stack frame returns",
+   "Upon return, the value returned is printed and put in the value history.\n",
+    &CLIDebugger::finishCommand));
+
+  //===--------------------------------------------------------------------===//
+  // Stack frame commands
+  //
+  addCommand("backtrace", C = new BuiltinCLICommand(
+   "Print backtrace of all stack frames, or innermost COUNT frames",
+   "FIXME: describe.  Takes 'n', '-n' or 'full'\n",
+    &CLIDebugger::backtraceCommand));
+  addCommand("bt", C); 
+ 
+  addCommand("up", new BuiltinCLICommand(
+    "Select and print stack frame that called this one",
+    "An argument says how many frames up to go.\n",
+    &CLIDebugger::upCommand));
+
+  addCommand("down", new BuiltinCLICommand(
+    "Select and print stack frame called by this one",
+    "An argument says how many frames down go.\n",
+    &CLIDebugger::downCommand));
+
+  addCommand("frame", C = new BuiltinCLICommand(
+    "Select and print a stack frame",
+ "With no argument, print the selected stack frame.  (See also 'info frame').\n"
+ "An argument specifies the frame to select.\n",
+    &CLIDebugger::frameCommand));
+  addCommand("f", C); 
+
+  //===--------------------------------------------------------------------===//
+  // Breakpoint related commands
+  //
+  addCommand("break", C = new BuiltinCLICommand(
+   "Set breakpoint at specified line or function",
+   "FIXME: describe.\n",
+    &CLIDebugger::breakCommand));
+  addCommand("b", C); 
+
+
+  //===--------------------------------------------------------------------===//
+  // Miscellaneous commands
+  //
+  addCommand("info", new BuiltinCLICommand(
+    "Generic command for showing things about the program being debugged",
+    "FIXME: document\n",
+    &CLIDebugger::infoCommand));
+
+  addCommand("list", C = new BuiltinCLICommand(
+    "List specified function or line",
+    "FIXME: document\n",
+    &CLIDebugger::listCommand));
+  addCommand("l", C);
+
+  addCommand("set", new BuiltinCLICommand(
+    "Change program or debugger variable",
+    "FIXME: document\n",
+    &CLIDebugger::setCommand));
+
+  addCommand("show", new BuiltinCLICommand(
+    "Generic command for showing things about the debugger",
+    "FIXME: document\n",
+    &CLIDebugger::showCommand));
+
+  addCommand("help", C = new BuiltinCLICommand(
+    "Prints information about available commands", "",
+    &CLIDebugger::helpCommand));
+  addCommand("h", C);
+}
+
+
+/// addCommand - Add a command to the CommandTable, potentially displacing a
+/// preexisting command.
+void CLIDebugger::addCommand(const std::string &Option, CLICommand *Cmd) {
+  assert(Cmd && "Cannot set a null command!");
+  CLICommand *&CS = CommandTable[Option];
+  if (CS == Cmd) return; // noop
+
+  // If we already have a command, decrement the command's reference count.
+  if (CS) {
+    CS->removeOptionName(Option);
+    CS->dropRef();
+  }
+  CS = Cmd;
+
+  // Remember that we are using this command.
+  Cmd->addRef();
+  Cmd->addOptionName(Option);
+}
+
+static bool isValidPrefix(const std::string &Prefix, const std::string &Option){
+  return Prefix.size() <= Option.size() &&
+         Prefix == std::string(Option.begin(), Option.begin()+Prefix.size());
+}
+
+/// getCommand - This looks up the specified command using a fuzzy match.
+/// If the string exactly matches a command or is an unambiguous prefix of a
+/// command, it returns the command.  Otherwise it throws an exception
+/// indicating the possible ambiguous choices.
+CLICommand *CLIDebugger::getCommand(const std::string &Command) {
+
+  // Look up the command in the table.
+  std::map<std::string, CLICommand*>::iterator CI =
+    CommandTable.lower_bound(Command);
+      
+  if (Command == "") {
+    throw "Null command not implemented yet.";
+  } else if (CI == CommandTable.end() ||
+             !isValidPrefix(Command, CI->first)) {
+    // If this command has no relation to anything in the command table,
+    // print the error message.
+    throw "Unknown command: '" + Command +
+          "'.  Use 'help' for list of commands.";
+  } else if (CI->first == Command) {
+    // We have an exact match on the command
+    return CI->second;
+  } else {
+    // Otherwise, we have a prefix match.  Check to see if this is
+    // unambiguous, and if so, run it.
+    std::map<std::string, CLICommand*>::iterator CI2 = CI;
+
+    // If the next command is a valid completion of this one, we are
+    // ambiguous.
+    if (++CI2 != CommandTable.end() && isValidPrefix(Command, CI2->first)) {
+      std::string ErrorMsg = 
+        "Ambiguous command '" + Command + "'.  Options: " + CI->first;
+      for (++CI; CI != CommandTable.end() &&
+             isValidPrefix(Command, CI->first); ++CI)
+        ErrorMsg += ", " + CI->first;
+      throw ErrorMsg;
+    } else {
+      // It's an unambiguous prefix of a command, use it.
+      return CI->second;
+    }
+  }
+}
+
+
+/// run - Start the debugger, returning when the user exits the debugger.  This
+/// starts the main event loop of the CLI debugger.
+///
+int CLIDebugger::run() {
+  std::string Command;
+  std::cout << Prompt;
+
+  // Continue reading commands until the end of file.
+  while (getline(std::cin, Command)) {
+    std::string Arguments = Command;
+
+    // Split off the command from the arguments to the command.
+    Command = getToken(Arguments, " \t\n\v\f\r\\/;.*&");
+
+    try {
+      // Look up the command and execute it.
+      getCommand(Command)->runCommand(*this, Arguments);      
+
+    } catch (int RetVal) {
+      // The quit command exits the command loop by throwing an integer return
+      // code.
+      return RetVal;
+    } catch (const std::string &Error) {
+      std::cout << "Error: " << Error << "\n";
+    } catch (const char *Error) {
+      std::cout << "Error: " << Error << "\n";
+    } catch (const NonErrorException &E) {
+      std::cout << E.getMessage() << "\n";
+    } catch (...) {
+      std::cout << "ERROR: Debugger caught unexpected exception!\n";
+      // Attempt to continue.
+    }
+    
+    // Write the prompt to get the next bit of user input
+    std::cout << Prompt;
+  }
+
+  return 0;
+}
+
+
+/// askYesNo - Ask the user a question, and demand a yes/no response.  If
+/// the user says yes, return true.
+///
+bool CLIDebugger::askYesNo(const std::string &Message) const {
+  std::string Answer;
+  std::cout << Message << " (y or n) " << std::flush;
+  while (getline(std::cin, Answer)) {
+    std::string Val = getToken(Answer);
+    if (getToken(Answer).empty()) {
+      if (Val == "yes" || Val == "y" || Val == "YES" || Val == "Y" ||
+          Val == "Yes")
+        return true;
+      if (Val == "no" || Val == "n" || Val == "NO" || Val == "N" ||
+          Val == "No")
+        return false;
+    }
+
+    std::cout << "Please answer y or n.\n" << Message << " (y or n) "
+              << std::flush;
+  }
+  
+  // Ran out of input?
+  return false;
+}
diff --git a/tools/llvm-db/CLIDebugger.h b/tools/llvm-db/CLIDebugger.h
new file mode 100644
index 0000000000..046c2e8429
--- /dev/null
+++ b/tools/llvm-db/CLIDebugger.h
@@ -0,0 +1,200 @@
+//===- CLIDebugger.h - LLVM Command Line Interface Debugger -----*- C++ -*-===//
+// 
+//                     The LLVM Compiler Infrastructure
+//
+// This file was developed by the LLVM research group and is distributed under
+// the University of Illinois Open Source License. See LICENSE.TXT for details.
+// 
+//===----------------------------------------------------------------------===//
+//
+// This file defines the CLIDebugger class, which implements a command line
+// interface to the LLVM Debugger library.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef CLIDEBUGGER_H
+#define CLIDEBUGGER_H
+
+#include "llvm/Debugger/Debugger.h"
+#include <map>
+
+namespace llvm {
+  class CLICommand;
+  class SourceFile;
+  class SourceLanguage;
+  class ProgramInfo;
+  class RuntimeInfo;
+
+  /// CLIDebugger - This class implements the command line interface for the
+  /// LLVM debugger.
+  class CLIDebugger {
+    /// Dbg - The low-level LLVM debugger object that we use to do our dirty
+    /// work.
+    Debugger Dbg;
+
+    /// CommandTable - This table contains a mapping from command names to the
+    /// CLICommand object that implements the command.
+    std::map<std::string, CLICommand*> CommandTable;
+
+    //===------------------------------------------------------------------===//
+    // Data related to the program that is currently loaded.  Note that the Dbg
+    // variable also captures some information about the loaded program.  This
+    // pointer is non-null iff Dbg.isProgramLoaded() is true.
+    //
+    ProgramInfo *TheProgramInfo;
+
+    //===------------------------------------------------------------------===//
+    // Data related to the program that is currently executing, but has stopped.
+    // Note that the Dbg variable also captures some information about the
+    // loaded program.  This pointer is non-null iff Dbg.isProgramRunning() is
+    // true.
+    //
+    RuntimeInfo *TheRuntimeInfo;
+
+    /// LastCurrentFrame - This variable holds the Frame ID of the top-level
+    /// stack frame from the last time that the program was executed.  We keep
+    /// this because we only want to print the source location when the current
+    /// function changes.
+    void *LastCurrentFrame;
+
+    //===------------------------------------------------------------------===//
+    // Data directly exposed through the debugger prompt
+    //
+    std::string Prompt;   // set prompt, show prompt
+    unsigned ListSize;    // set listsize, show listsize
+    
+    //===------------------------------------------------------------------===//
+    // Data to support user interaction
+    //
+    
+    /// CurrentFile - The current source file we are inspecting, or null if
+    /// none.
+    const SourceFile *CurrentFile;
+    unsigned LineListedStart, LineListedEnd;
+
+    /// CurrentLanguage - This contains the source language in use, if one is
+    /// explicitly set by the user.  If this is null (the default), the language
+    /// is automatically determined from the current stack frame.
+    ///
+    const SourceLanguage *CurrentLanguage;
+
+  public:
+    CLIDebugger();
+
+    /// getDebugger - Return the current LLVM debugger implementation being
+    /// used.
+    Debugger &getDebugger() { return Dbg; }
+
+    /// run - Start the debugger, returning when the user exits the debugger.
+    /// This starts the main event loop of the CLI debugger.
+    ///
+    int run();
+
+    /// addCommand - Add a command to the CommandTable, potentially displacing a
+    /// preexisting command.
+    void addCommand(const std::string &Option, CLICommand *Cmd);
+
+    /// addSourceDirectory - Add a directory to search when looking for the
+    /// source code of the program.
+    void addSourceDirectory(const std::string &Dir) {
+      // FIXME: implement
+    }
+
+    /// getCurrentLanguage - Return the current source language that the user is
+    /// playing around with.  This is aquired from the current stack frame of a
+    /// running program if one exists, but this value can be explicitly set by
+    /// the user as well.
+    const SourceLanguage &getCurrentLanguage() const;
+
+    /// getProgramInfo - Return a reference to the ProgramInfo object for the
+    /// currently loaded program.  If there is no program loaded, throw an
+    /// exception.
+    ProgramInfo &getProgramInfo() const {
+      if (TheProgramInfo == 0)
+        throw "No program is loaded.";
+      return *TheProgramInfo;
+    }
+
+    /// getRuntimeInfo - Return a reference to the current RuntimeInfo object.
+    /// If there is no program running, throw an exception.
+    RuntimeInfo &getRuntimeInfo() const {
+      if (TheRuntimeInfo == 0)
+        throw "No program is running.";
+      return *TheRuntimeInfo;
+    }
+
+  private:   // Internal implementation methods
+
+    /// getCommand - This looks up the specified command using a fuzzy match.
+    /// If the string exactly matches a command or is an unambiguous prefix of a
+    /// command, it returns the command.  Otherwise it throws an exception
+    /// indicating the possible ambiguous choices.
+    CLICommand *getCommand(const std::string &Command);
+
+    /// askYesNo - Ask the user a question, and demand a yes/no response.  If
+    /// the user says yes, return true.
+    bool askYesNo(const std::string &Message) const;
+
+    /// printProgramLocation - Given a loaded and created child process that has
+    /// stopped, print its current source location.
+    void printProgramLocation(bool PrintLocation = true);
+
+    /// eliminateRunInfo - We are about to run the program.  Forget any state
+    /// about how the program used to be stopped.
+    void eliminateRunInfo();
+
+    /// programStoppedSuccessfully - This method updates internal data
+    /// structures to reflect the fact that the program just executed a while,
+    /// and has successfully stopped.
+    void programStoppedSuccessfully();
+
+  public:   /// Builtin debugger commands, invokable by the user
+    // Program startup and shutdown options
+    void fileCommand(std::string &Options);   // file
+    void createCommand(std::string &Options); // create
+    void killCommand(std::string &Options);   // kill
+    void quitCommand(std::string &Options);   // quit
+
+    // Program execution commands
+    void runCommand(std::string &Options);    // run|r
+    void contCommand(std::string &Options);   // cont|c|fg
+    void stepCommand(std::string &Options);   // step|s [count]
+    void nextCommand(std::string &Options);   // next|n [count]
+    void finishCommand(std::string &Options); // finish
+
+    // Stack frame commands
+    void backtraceCommand(std::string &Options); // backtrace|bt [count]
+    void upCommand(std::string &Options);        // up
+    void downCommand(std::string &Options);      // down
+    void frameCommand(std::string &Options);     // frame
+
+
+    // Breakpoint related commands
+    void breakCommand(std::string &Options);  // break|b <id>
+
+    // Miscellaneous commands
+    void infoCommand(std::string &Options);   // info
+    void listCommand(std::string &Options);   // list
+    void setCommand(std::string &Options);    // set
+    void showCommand(std::string &Options);   // show
+    void helpCommand(std::string &Options);   // help
+
+  private:
+    /// startProgramRunning - If the program has been updated, reload it, then
+    /// start executing the program.
+    void startProgramRunning();
+
+    /// parseLineSpec - Parses a line specifier, for use by the 'list' command.
+    /// If SourceFile is returned as a void pointer, then it was not specified.
+    /// If the line specifier is invalid, an exception is thrown.
+    void parseLineSpec(std::string &LineSpec, const SourceFile *&SourceFile,
+                       unsigned &LineNo);
+
+    /// printSourceLine - Print the specified line of the current source file.
+    /// If the specified line is invalid (the source file could not be loaded or
+    /// the line number is out of range), don't print anything, but return true.
+    bool printSourceLine(unsigned LineNo);
+  };
+}
+
+#endif
diff --git a/tools/llvm-db/Commands.cpp b/tools/llvm-db/Commands.cpp
new file mode 100644
index 0000000000..9d0bcbada5
--- /dev/null
+++ b/tools/llvm-db/Commands.cpp
@@ -0,0 +1,803 @@
+//===-- Commands.cpp - Implement various commands for the CLI -------------===//
+// 
+//                     The LLVM Compiler Infrastructure
+//
+// This file was developed by the LLVM research group and is distributed under
+// the University of Illinois Open Source License. See LICENSE.TXT for details.
+// 
+//===----------------------------------------------------------------------===//
+// 
+// This file implements many builtin user commands.
+//
+//===----------------------------------------------------------------------===//
+
+#include "CLIDebugger.h"
+#include "CLICommand.h"
+#include "llvm/Debugger/ProgramInfo.h"
+#include "llvm/Debugger/RuntimeInfo.h"
+#include "llvm/Debugger/SourceLanguage.h"
+#include "llvm/Debugger/SourceFile.h"
+#include "llvm/Debugger/InferiorProcess.h"
+#include "Support/FileUtilities.h"
+#include "Support/StringExtras.h"
+#include <iostream>
+using namespace llvm;
+
+/// getCurrentLanguage - Return the current source language that the user is
+/// playing around with.  This is aquired from the current stack frame of a
+/// running program if one exists, but this value can be explicitly set by the
+/// user as well.
+const SourceLanguage &CLIDebugger::getCurrentLanguage() const {
+  // If the user explicitly switched languages with 'set language', use what
+  // they asked for.
+  if (CurrentLanguage) {
+    return *CurrentLanguage;
+  } else if (Dbg.isProgramRunning()) {
+    // Otherwise, if the program is running, infer the current language from it.
+    const GlobalVariable *FuncDesc =
+      getRuntimeInfo().getCurrentFrame().getFunctionDesc();
+    return getProgramInfo().getFunction(FuncDesc).getSourceFile().getLanguage();
+  } else {
+    // Otherwise, default to C like GDB apparently does.
+    return SourceLanguage::getCFamilyInstance();
+  }
+}
+
+/// startProgramRunning - If the program has been updated, reload it, then
+/// start executing the program.
+void CLIDebugger::startProgramRunning() {
+  eliminateRunInfo();
+
+  // If the program has been modified, reload it!
+  std::string Program = Dbg.getProgramPath();
+  if (TheProgramInfo->getProgramTimeStamp() != getFileTimestamp(Program)) {
+    std::cout << "'" << Program << "' has changed; re-reading program.\n";
+
+    // Unload an existing program.  This kills the program if necessary.
+    Dbg.unloadProgram();
+    delete TheProgramInfo;
+    TheProgramInfo = 0;
+    CurrentFile = 0;
+
+    Dbg.loadProgram(Program);
+    TheProgramInfo = new ProgramInfo(Dbg.getProgram());
+  }
+
+  std::cout << "Starting program: " << Dbg.getProgramPath() << "\n";
+  Dbg.createProgram();
+
+  // There was no current frame.
+  LastCurrentFrame = 0;
+}
+
+/// printSourceLine - Print the specified line of the current source file.
+/// If the specified line is invalid (the source file could not be loaded or
+/// the line number is out of range), don't print anything, but return true.
+bool CLIDebugger::printSourceLine(unsigned LineNo) {
+  assert(CurrentFile && "There is no current source file to print!");
+  const char *LineStart, *LineEnd;
+  CurrentFile->getSourceLine(LineNo-1, LineStart, LineEnd);
+  if (LineStart == 0) return true;
+  std::cout << LineNo;
+
+  // If this is the line the program is currently stopped at, print a marker.
+  if (Dbg.isProgramRunning()) {
+    unsigned CurLineNo, CurColNo;
+    const SourceFileInfo *CurSFI;
+    getRuntimeInfo().getCurrentFrame().getSourceLocation(CurLineNo, CurColNo,
+                                                         CurSFI);
+
+    if (CurLineNo == LineNo && CurrentFile == &CurSFI->getSourceText())
+      std::cout << " ->";
+  }
+
+  std::cout << "\t" << std::string(LineStart, LineEnd) << "\n"; 
+  return false;
+}
+
+/// printProgramLocation - Print a line of the place where the current stack
+/// frame has stopped and the source line it is on.
+///
+void CLIDebugger::printProgramLocation(bool PrintLocation) {
+  assert(Dbg.isProgramLoaded() && Dbg.isProgramRunning() &&
+         "Error program is not loaded and running!");
+
+  // Figure out where the program stopped...
+  StackFrame &SF = getRuntimeInfo().getCurrentFrame();
+  unsigned LineNo, ColNo;
+  const SourceFileInfo *FileDesc;
+  SF.getSourceLocation(LineNo, ColNo, FileDesc);
+
+  // If requested, print out some program information about WHERE we are.
+  if (PrintLocation) {
+    // FIXME: print the current function arguments
+    if (const GlobalVariable *FuncDesc = SF.getFunctionDesc())
+      std::cout << getProgramInfo().getFunction(FuncDesc).getSymbolicName();
+    else
+      std::cout << "<unknown function>";
+    
+    CurrentFile = &FileDesc->getSourceText();
+    
+    std::cout << " at " << CurrentFile->getFilename() << ":" << LineNo;
+    if (ColNo) std::cout << ":" << ColNo << "\n";
+  }
+
+  if (printSourceLine(LineNo))
+    std::cout << "<could not load source file>\n";
+  else {
+    LineListedStart = LineNo-ListSize/2+1;
+    if ((int)LineListedStart < 1) LineListedStart = 1;
+    LineListedEnd = LineListedStart+1;
+  }
+}
+
+/// eliminateRunInfo - We are about to run the program.  Forget any state
+/// about how the program used to be stopped.
+void CLIDebugger::eliminateRunInfo() {
+  delete TheRuntimeInfo;
+  TheRuntimeInfo = 0;
+}
+
+/// programStoppedSuccessfully - This method updates internal data
+/// structures to reflect the fact that the program just executed a while,
+/// and has successfully stopped.
+void CLIDebugger::programStoppedSuccessfully() {
+  assert(TheRuntimeInfo==0 && "Someone forgot to release the old RuntimeInfo!");
+
+  TheRuntimeInfo = new RuntimeInfo(TheProgramInfo, Dbg.getRunningProcess());
+
+  // FIXME: if there are any breakpoints at the current location, print them as
+  // well.
+
+  // Since the program as successfully stopped, print its location.
+  void *CurrentFrame = getRuntimeInfo().getCurrentFrame().getFrameID();
+  printProgramLocation(CurrentFrame != LastCurrentFrame);
+  LastCurrentFrame = CurrentFrame;
+}
+
+
+
+/// getUnsignedIntegerOption - Get an unsigned integer number from the Val
+/// string.  Check to make sure that the string contains an unsigned integer
+/// token, and if not, throw an exception.  If isOnlyOption is set, also throw
+/// an exception if there is extra junk at the end of the string.
+static unsigned getUnsignedIntegerOption(const char *Msg, std::string &Val,
+                                         bool isOnlyOption = true) {
+  std::string Tok = getToken(Val);
+  if (Tok.empty() || (isOnlyOption && !getToken(Val).empty()))
+    throw std::string(Msg) + " expects an unsigned integer argument.";
+  
+  char *EndPtr;
+  unsigned Result = strtoul(Tok.c_str(), &EndPtr, 0);
+  if (EndPtr != Tok.c_str()+Tok.size())
+    throw std::string(Msg) + " expects an unsigned integer argument.";
+
+  return Result;
+}
+
+/// getOptionalUnsignedIntegerOption - This method is just like
+/// getUnsignedIntegerOption, but if the argument value is not specified, a
+/// default is returned instead of causing an error.
+static unsigned 
+getOptionalUnsignedIntegerOption(const char *Msg, unsigned Default,
+                                 std::string &Val, bool isOnlyOption = true) {
+  // Check to see if the value was specified...
+  std::string TokVal = getToken(Val);
+  if (TokVal.empty()) return Default;
+
+  // If it was specified, add it back to the value we are parsing...
+  Val = TokVal+Val;
+
+  // And parse normally.
+  return getUnsignedIntegerOption(Msg, Val, isOnlyOption);
+}
+                                                 
+
+//===----------------------------------------------------------------------===//
+//                   Program startup and shutdown options
+//===----------------------------------------------------------------------===//
+
+
+/// file command - If the user specifies an option, search the PATH for the
+/// specified program/bytecode file and load it.  If the user does not specify
+/// an option, unload the current program.
+void CLIDebugger::fileCommand(std::string &Options) {
+  std::string Prog = getToken(Options);
+  if (!getToken(Options).empty())
+    throw "file command takes at most one argument.";
+
+  // Check to make sure the user knows what they are doing
+  if (Dbg.isProgramRunning() &&
+      !askYesNo("A program is already loaded.  Kill it?"))
+    return;
+
+  // Unload an existing program.  This kills the program if necessary.
+  eliminateRunInfo();
+  delete TheProgramInfo;
+  TheProgramInfo = 0;
+  Dbg.unloadProgram();
+  CurrentFile = 0;
+
+  // If requested, start the new program.
+  if (Prog.empty()) {
+    std::cout << "Unloaded program.\n";
+  } else {
+    std::cout << "Loading program... " << std::flush;
+    Dbg.loadProgram(Prog);
+    assert(Dbg.isProgramLoaded() &&
+           "loadProgram succeeded, but not program loaded!");
+    TheProgramInfo = new ProgramInfo(Dbg.getProgram());
+    std::cout << "success loading '" << Dbg.getProgramPath() << "'!\n";
+  }
+}
+
+
+void CLIDebugger::createCommand(std::string &Options) {
+  if (!getToken(Options).empty())
+    throw "create command does not take any arguments.";
+  if (!Dbg.isProgramLoaded()) throw "No program loaded.";
+  if (Dbg.isProgramRunning() &&
+      !askYesNo("The program is already running.  Restart from the beginning?"))
+    return;
+
+  // Start the program running.
+  startProgramRunning();
+
+  // The program stopped!
+  programStoppedSuccessfully();
+}
+
+void CLIDebugger::killCommand(std::string &Options) {
+  if (!getToken(Options).empty())
+    throw "kill command does not take any arguments.";
+  if (!Dbg.isProgramRunning())
+    throw "No program is currently being run.";
+
+  if (askYesNo("Kill the program being debugged?"))
+    Dbg.killProgram();
+  eliminateRunInfo();
+}
+
+void CLIDebugger::quitCommand(std::string &Options) {
+  if (!getToken(Options).empty())
+    throw "quit command does not take any arguments.";
+
+  if (Dbg.isProgramRunning() &&
+      !askYesNo("The program is running.  Exit anyway?"))
+    return;
+
+  // Throw exception to get out of the user-input loop.
+  throw 0;
+}
+
+
+//===----------------------------------------------------------------------===//
+//                        Program execution commands
+//===----------------------------------------------------------------------===//
+
+void CLIDebugger::runCommand(std::string &Options) {
+  if (!getToken(Options).empty()) throw "run arguments not supported yet.";
+  if (!Dbg.isProgramLoaded()) throw "No program loaded.";
+  if (Dbg.isProgramRunning() &&
+      !askYesNo("The program is already running.  Restart from the beginning?"))
+    return;
+
+  eliminateRunInfo();
+
+  // Start the program running.
+  startProgramRunning();
+
+  // Start the program running...
+  Options = "";
+  contCommand(Options);
+}
+
+void CLIDebugger::contCommand(std::string &Options) {
+  if (!getToken(Options).empty()) throw "cont argument not supported yet.";
+  if (!Dbg.isProgramRunning()) throw "Program is not running.";
+
+  eliminateRunInfo();
+
+  Dbg.contProgram();
+
+  // The program stopped!
+  programStoppedSuccessfully();
+}
+
+void CLIDebugger::stepCommand(std::string &Options) {
+  if (!Dbg.isProgramRunning()) throw "Program is not running.";
+
+  // Figure out how many times to step.
+  unsigned Amount =
+    getOptionalUnsignedIntegerOption("'step' command", 1, Options);
+
+  eliminateRunInfo();
+
+  // Step the specified number of times.
+  for (; Amount; --Amount)
+    Dbg.stepProgram();
+
+  // The program stopped!
+  programStoppedSuccessfully();
+}
+
+void CLIDebugger::nextCommand(std::string &Options) {
+  if (!Dbg.isProgramRunning()) throw "Program is not running.";
+  unsigned Amount =
+    getOptionalUnsignedIntegerOption("'next' command", 1, Options);
+
+  eliminateRunInfo();
+
+  for (; Amount; --Amount)
+    Dbg.nextProgram();
+
+  // The program stopped!
+  programStoppedSuccessfully();
+}
+
+void CLIDebugger::finishCommand(std::string &Options) {
+  if (!getToken(Options).empty())
+    throw "finish command does not take any arguments.";
+  if (!Dbg.isProgramRunning()) throw "Program is not running.";
+
+  // Figure out where we are exactly.  If the user requests that we return from
+  // a frame that is not the top frame, make sure we get it.
+  void *CurrentFrame = getRuntimeInfo().getCurrentFrame().getFrameID();
+
+  eliminateRunInfo();
+
+  Dbg.finishProgram(CurrentFrame);
+
+  // The program stopped!
+  programStoppedSuccessfully();
+}
+
+//===----------------------------------------------------------------------===//
+//                           Stack frame commands
+//===----------------------------------------------------------------------===//
+
+void CLIDebugger::backtraceCommand(std::string &Options) {
+  // Accepts "full", n, -n
+  if (!getToken(Options).empty())
+    throw "FIXME: bt command argument not implemented yet!";
+
+  RuntimeInfo &RI = getRuntimeInfo();
+  ProgramInfo &PI = getProgramInfo();
+
+  try {
+    for (unsigned i = 0; ; ++i) {
+      StackFrame &SF = RI.getStackFrame(i);
+      std::cout << "#" << i;
+      if (i == RI.getCurrentFrameIdx())
+        std::cout << " ->";
+      std::cout << "\t" << SF.getFrameID() << " in ";
+      if (const GlobalVariable *G = SF.getFunctionDesc())
+        std::cout << PI.getFunction(G).getSymbolicName();
+
+      unsigned LineNo, ColNo;
+      const SourceFileInfo *SFI;
+      SF.getSourceLocation(LineNo, ColNo, SFI);
+      if (!SFI->getBaseName().empty()) {
+        std::cout << " at " << SFI->getBaseName();
+        if (LineNo) {
+          std::cout << ":" << LineNo;
+          if (ColNo)
+            std::cout << ":" << ColNo;
+        }
+      }
+
+      // FIXME: when we support shared libraries, we should print ' from foo.so'
+      // if the stack frame is from a different object than the current one.
+
+      std::cout << "\n";
+    }
+  } catch (...) {
+    // Stop automatically when we run off the bottom of the stack.
+  }
+}
+
+void CLIDebugger::upCommand(std::string &Options) {
+  unsigned Num =
+    getOptionalUnsignedIntegerOption("'up' command", 1, Options);
+
+  RuntimeInfo &RI = getRuntimeInfo();
+  unsigned CurFrame = RI.getCurrentFrameIdx();
+
+  // Check to see if we go can up the specified number of frames.
+  try {
+    RI.getStackFrame(CurFrame+Num);
+  } catch (...) {
+    if (Num == 1)
+      throw "Initial frame selected; you cannot go up.";
+    else
+      throw "Cannot go up " + utostr(Num) + " frames!";
+  }
+
+  RI.setCurrentFrameIdx(CurFrame+Num);
+  printProgramLocation();
+}
+
+void CLIDebugger::downCommand(std::string &Options) {
+  unsigned Num =
+    getOptionalUnsignedIntegerOption("'down' command", 1, Options);
+
+  RuntimeInfo &RI = getRuntimeInfo();
+  unsigned CurFrame = RI.getCurrentFrameIdx();
+
+  // Check to see if we can go up the specified number of frames.
+  if (CurFrame < Num)
+    if (Num == 1)
+      throw "Bottom (i.e., innermost) frame selected; you cannot go down.";
+    else
+      throw "Cannot go down " + utostr(Num) + " frames!";
+
+  RI.setCurrentFrameIdx(CurFrame-Num);
+  printProgramLocation();
+}
+
+void CLIDebugger::frameCommand(std::string &Options) {
+  RuntimeInfo &RI = getRuntimeInfo();
+  unsigned CurFrame = RI.getCurrentFrameIdx();
+
+  unsigned Num =
+    getOptionalUnsignedIntegerOption("'frame' command", CurFrame, Options);
+
+  // Check to see if we go to the specified frame.
+  RI.getStackFrame(Num);
+
+  RI.setCurrentFrameIdx(Num);
+  printProgramLocation();
+}
+
+
+//===----------------------------------------------------------------------===//
+//                        Breakpoint related commands
+//===----------------------------------------------------------------------===//
+
+void CLIDebugger::breakCommand(std::string &Options) {
+  throw "breakpoints not implemented yet!";
+}
+
+//===----------------------------------------------------------------------===//
+//                          Miscellaneous commands
+//===----------------------------------------------------------------------===//
+
+void CLIDebugger::infoCommand(std::string &Options) {
+  std::string What = getToken(Options);
+
+  if (What.empty() || !getToken(Options).empty())
+    throw "info command expects exactly one argument.";
+
+  if (What == "frame") {
+  } else if (What == "functions") {
+    const std::map<const GlobalVariable*, SourceFunctionInfo*> &Functions
+      = getProgramInfo().getSourceFunctions();
+    std::cout << "All defined functions:\n";
+    // FIXME: GDB groups these by source file.  We could do that I guess.
+    for (std::map<const GlobalVariable*, SourceFunctionInfo*>::const_iterator
+           I = Functions.begin(), E = Functions.end(); I != E; ++I) {
+      std::cout << I->second->getSymbolicName() << "\n";
+    }
+
+  } else if (What == "source") {
+    if (CurrentFile == 0)
+      throw "No current source file.";
+
+    // Get the SourceFile information for the current file.
+    const SourceFileInfo &SF =
+      getProgramInfo().getSourceFile(CurrentFile->getDescriptor());
+
+    std::cout << "Current source file is: " << SF.getBaseName() << "\n"
+              << "Compilation directory is: " << SF.getDirectory() << "\n";
+    if (unsigned NL = CurrentFile->getNumLines())
+      std::cout << "Located in: " << CurrentFile->getFilename() << "\n"
+                << "Contains " << NL << " lines\n";
+    else
+      std::cout << "Could not find source file.\n";
+    std::cout << "Source language is "
+              << SF.getLanguage().getSourceLanguageName() << "\n";
+
+  } else if (What == "sources") {
+    const std::map<const GlobalVariable*, SourceFileInfo*> &SourceFiles = 
+      getProgramInfo().getSourceFiles();
+    std::cout << "Source files for the program:\n";
+    for (std::map<const GlobalVariable*, SourceFileInfo*>::const_iterator I =
+           SourceFiles.begin(), E = SourceFiles.end(); I != E;) {
+      std::cout << I->second->getDirectory() << "/"
+                << I->second->getBaseName();
+      ++I;
+      if (I != E) std::cout << ", ";
+    }
+    std::cout << "\n";
+  } else if (What == "target") {
+    std::cout << Dbg.getRunningProcess().getStatus();
+  } else {
+    // See if this is something handled by the current language.
+    if (getCurrentLanguage().printInfo(What))
+      return;
+
+    throw "Unknown info command '" + What + "'.  Try 'help info'.";
+  }
+}
+
+/// parseLineSpec - Parses a line specifier, for use by the 'list' command.
+/// If SourceFile is returned as a void pointer, then it was not specified.
+/// If the line specifier is invalid, an exception is thrown.
+void CLIDebugger::parseLineSpec(std::string &LineSpec,
+                                const SourceFile *&SourceFile,
+                                unsigned &LineNo) {
+  SourceFile = 0;
+  LineNo = 0;
+
+  // First, check to see if we have a : separator.
+  std::string FirstPart = getToken(LineSpec, ":");
+  std::string SecondPart = getToken(LineSpec, ":");
+  if (!getToken(LineSpec).empty()) throw "Malformed line specification!";
+
+  // If there is no second part, we must have either "function", "number",
+  // "+offset", or "-offset".
+  if (SecondPart.empty()) {
+    if (FirstPart.empty()) throw "Malformed line specification!";
+    if (FirstPart[0] == '+') {
+      FirstPart.erase(FirstPart.begin(), FirstPart.begin()+1);
+      // For +n, return LineListedEnd+n
+      LineNo = LineListedEnd +
+               getUnsignedIntegerOption("Line specifier '+'", FirstPart);
+
+    } else if (FirstPart[0] == '-') {
+      FirstPart.erase(FirstPart.begin(), FirstPart.begin()+1);
+      // For -n, return LineListedEnd-n
+      LineNo = LineListedEnd -
+               getUnsignedIntegerOption("Line specifier '-'", FirstPart);
+      if ((int)LineNo < 1) LineNo = 1;
+    } else if (FirstPart[0] == '*') {
+      throw "Address expressions not supported as source locations!";
+    } else {
+      // Ok, check to see if this is just a line number.
+      std::string Saved = FirstPart;
+      try {
+        LineNo = getUnsignedIntegerOption("", Saved);
+      } catch (...) {
+        // Ok, it's not a valid line number.  It must be a source-language
+        // entity name.
+        std::string Name = getToken(FirstPart);
+        if (!getToken(FirstPart).empty())
+          throw "Extra junk in line specifier after '" + Name + "'.";
+        SourceFunctionInfo *SFI = 
+          getCurrentLanguage().lookupFunction(Name, getProgramInfo(),
+                                              TheRuntimeInfo);
+        if (SFI == 0)
+          throw "Unknown identifier '" + Name + "'.";
+
+        unsigned L, C;
+        SFI->getSourceLocation(L, C);
+        if (L == 0) throw "Could not locate '" + Name + "'!";
+        LineNo = L;
+        SourceFile = &SFI->getSourceFile().getSourceText();
+        return;
+      }
+    }
+
+  } else {
+    // Ok, this must be a filename qualified line number or function name.
+    // First, figure out the source filename.
+    std::string SourceFilename = getToken(FirstPart);
+    if (!getToken(FirstPart).empty())
+      throw "Invalid filename qualified source location!";
+
+    // Next, check to see if this is just a line number.
+    std::string Saved = SecondPart;
+    try {
+      LineNo = getUnsignedIntegerOption("", Saved);
+    } catch (...) {
+      // Ok, it's not a valid line number.  It must be a function name.
+      throw "FIXME: Filename qualified function names are not support "
+            "as line specifiers yet!";
+    }
+
+    // Ok, we got the line number.  Now check out the source file name to make
+    // sure it's all good.  If it is, return it.  If not, throw exception.
+    SourceFile =&getProgramInfo().getSourceFile(SourceFilename).getSourceText();
+  }
+}
+
+void CLIDebugger::listCommand(std::string &Options) {
+  if (!Dbg.isProgramLoaded())
+    throw "No program is loaded.  Use the 'file' command.";
+
+  // Handle "list foo," correctly, by returning " " as the second token
+  Options += " ";
+  
+  std::string FirstLineSpec = getToken(Options, ",");
+  std::string SecondLineSpec = getToken(Options, ",");
+  if (!getToken(Options, ",").empty())
+    throw "list command only expects two source location specifiers!";
+
+  // StartLine, EndLine - The starting and ending line numbers to print.
+  unsigned StartLine = 0, EndLine = 0;
+
+  if (SecondLineSpec.empty()) {    // No second line specifier provided?
+    // Handle special forms like "", "+", "-", etc.
+    std::string TmpSpec = FirstLineSpec;
+    std::string Tok = getToken(TmpSpec);
+    if (getToken(TmpSpec).empty() && (Tok == "" || Tok == "+" || Tok == "-")) {
+      if (Tok == "+" || Tok == "") {
+        StartLine = LineListedEnd;
+        EndLine = StartLine + ListSize;
+      } else {
+        assert(Tok == "-");
+        StartLine = LineListedStart-ListSize;
+        EndLine = LineListedStart;
+        if ((int)StartLine < 0) StartLine = 1;
+      }
+    } else {
+      // Must be a normal line specifier.
+      const SourceFile *File;
+      unsigned LineNo;
+      parseLineSpec(FirstLineSpec, File, LineNo);
+
+      // If the user only specified one file specifier, we should display
+      // ListSize lines centered at the specified line.
+      if (File != 0) CurrentFile = File;
+      StartLine = LineNo - (ListSize+1)/2;
+      if ((int)StartLine < 0) StartLine = 1;
+      EndLine = StartLine + ListSize;
+    }
+
+  } else {
+    // Parse two line specifiers... 
+    const SourceFile *StartFile, *EndFile;
+    unsigned StartLineNo, EndLineNo;
+    parseLineSpec(FirstLineSpec, StartFile, StartLineNo);
+    unsigned SavedLLE = LineListedEnd;
+    LineListedEnd = StartLineNo;
+    try {
+      parseLineSpec(SecondLineSpec, EndFile, EndLineNo);
+    } catch (...) {
+      LineListedEnd = SavedLLE;
+      throw;
+    }
+
+    // Inherit file specified by the first line spec if there was one.
+    if (EndFile == 0) EndFile = StartFile;
+
+    if (StartFile != EndFile)
+      throw "Start and end line specifiers are in different files!";
+    CurrentFile = StartFile;
+    StartLine = StartLineNo;
+    EndLine = EndLineNo+1;
+  }
+
+  assert((int)StartLine > 0 && (int)EndLine > 0 && StartLine <= EndLine &&
+         "Error reading line specifiers!");
+
+  // If there was no current file, and the user didn't specify one to list, we
+  // have an error.
+  if (CurrentFile == 0)
+    throw "There is no current file to list.";
+
+  // Remember for next time.
+  LineListedStart = StartLine;
+  LineListedEnd = StartLine;
+
+  for (unsigned LineNo = StartLine; LineNo != EndLine; ++LineNo) {
+    // Print the source line, unless it is invalid.
+    if (printSourceLine(LineNo))
+      break;
+    LineListedEnd = LineNo+1;
+  }
+
+  // If we didn't print any lines, find out why.
+  if (LineListedEnd == StartLine) {
+    // See if we can read line #0 from the file, if not, we couldn't load the
+    // file.
+    const char *LineStart, *LineEnd;
+    CurrentFile->getSourceLine(0, LineStart, LineEnd);
+    if (LineStart == 0)
+      throw "Could not load source file '" + CurrentFile->getFilename() + "'!";
+    else
+      std::cout << "<end of file>\n";
+  }
+}
+
+void CLIDebugger::setCommand(std::string &Options) {
+  std::string What = getToken(Options);
+
+  if (What.empty())
+    throw "set command expects at least two arguments.";
+  if (What == "language") {
+    std::string Lang = getToken(Options);
+    if (!getToken(Options).empty())
+      throw "set language expects one argument at most.";
+    if (Lang == "") {
+      std::cout << "The currently understood settings are:\n\n"
+                << "local or auto  Automatic setting based on source file\n"
+                << "c              Use the C language\n"
+                << "c++            Use the C++ language\n"
+                << "unknown        Use when source language is not supported\n";
+    } else if (Lang == "local" || Lang == "auto") {
+      CurrentLanguage = 0;
+    } else if (Lang == "c") {
+      CurrentLanguage = &SourceLanguage::getCFamilyInstance();
+    } else if (Lang == "c++") {
+      CurrentLanguage = &SourceLanguage::getCPlusPlusInstance();
+    } else if (Lang == "unknown") {
+      CurrentLanguage = &SourceLanguage::getUnknownLanguageInstance();
+    } else {
+      throw "Unknown language '" + Lang + "'.";
+    }
+
+  } else if (What == "listsize") {
+    ListSize = getUnsignedIntegerOption("'set prompt' command", Options);
+  } else if (What == "prompt") {
+    // Include any trailing whitespace or other tokens, but not leading
+    // whitespace.
+    Prompt = getToken(Options);  // Strip leading whitespace
+    Prompt += Options;           // Keep trailing whitespace or other stuff
+  } else {
+    // FIXME: Try to parse this as a source-language program expression.
+    throw "Don't know how to set '" + What + "'!";
+  }
+}
+
+void CLIDebugger::showCommand(std::string &Options) {
+  std::string What = getToken(Options);
+
+  if (What.empty() || !getToken(Options).empty())
+    throw "show command expects one argument.";
+
+  if (What == "language") {
+    std::cout << "The current source language is '";
+    if (CurrentLanguage)
+      std::cout << CurrentLanguage->getSourceLanguageName();
+    else
+      std::cout << "auto; currently "
+                << getCurrentLanguage().getSourceLanguageName();
+    std::cout << "'.\n";
+  } else if (What == "listsize") {
+    std::cout << "Number of source lines llvm-db will list by default is "
+              << ListSize << ".\n";
+  } else if (What == "prompt") {
+    std::cout << "llvm-db's prompt is \"" << Prompt << "\".\n";
+  } else {
+    throw "Unknown show command '" + What + "'.  Try 'help show'.";
+  }
+}
+
+void CLIDebugger::helpCommand(std::string &Options) {
+  // Print out all of the commands in the CommandTable
+  std::string Command = getToken(Options);
+  if (!getToken(Options).empty())
+    throw "help command takes at most one argument.";
+
+  // Getting detailed help on a particular command?
+  if (!Command.empty()) {
+    CLICommand *C = getCommand(Command);
+    std::cout << C->getShortHelp() << ".\n" << C->getLongHelp();
+
+    // If there are aliases for this option, print them out.
+    const std::vector<std::string> &Names = C->getOptionNames();
+    if (Names.size() > 1) {
+      std::cout << "The '" << Command << "' command is known as: '"
+                << Names[0] << "'";
+      for (unsigned i = 1, e = Names.size(); i != e; ++i)
+        std::cout << ", '" << Names[i] << "'";
+      std::cout << "\n";
+    }
+
+  } else {
+    unsigned MaxSize = 0;
+    for (std::map<std::string, CLICommand*>::iterator I = CommandTable.begin(),
+           E = CommandTable.end(); I != E; ++I)
+      if (I->first.size() > MaxSize &&
+          I->first == I->second->getPrimaryOptionName())
+        MaxSize = I->first.size();
+
+    // Loop over all of the commands, printing the short help version
+    for (std::map<std::string, CLICommand*>::iterator I = CommandTable.begin(),
+           E = CommandTable.end(); I != E; ++I)
+      if (I->first == I->second->getPrimaryOptionName())
+        std::cout << I->first << std::string(MaxSize - I->first.size(), ' ')
+                  << " - " << I->second->getShortHelp() << "\n";
+  }
+}
diff --git a/tools/llvm-db/Makefile b/tools/llvm-db/Makefile
new file mode 100644
index 0000000000..e261f81c60
--- /dev/null
+++ b/tools/llvm-db/Makefile
@@ -0,0 +1,60 @@
+##===- tools/llvm-db/Makefile ------------------------------*- Makefile -*-===##
+# 
+#                     The LLVM Compiler Infrastructure
+#
+# This file was developed by the LLVM research group and is distributed under
+# the University of Illinois Open Source License. See LICENSE.TXT for details.
+# 
+##===----------------------------------------------------------------------===##
+
+LEVEL = ../..
+TOOLNAME = llvm-db
+
+# Get the $(ARCH) setting
+include $(LEVEL)/Makefile.config
+
+# Generic JIT libraries
+JITLIBS   = lli-jit codegen executionengine
+ARCHLIBS  =
+
+# You can enable the X86 JIT on a non-X86 host by setting the flag
+# ENABLE_X86_JIT on the make command line. If not, it will still be
+# enabled automagically on an X86 host.
+ifeq ($(ARCH), x86)
+  ENABLE_X86_JIT = 1
+endif
+
+# What the X86 JIT requires
+ifdef ENABLE_X86_JIT
+  CPPFLAGS += -DENABLE_X86_JIT
+  JITLIBS  += x86 selectiondag
+  # X86 doesn't require any ARCHLIBS
+endif
+
+# You can enable the Sparc JIT on a non-Sparc host by setting the flag
+# ENABLE_SPARC_JIT on the make command line. If not, it will still be
+# enabled automagically on an Sparc host.
+ifeq ($(ARCH), Sparc)
+  ENABLE_SPARC_JIT = 1
+endif
+
+# What the Sparc JIT requires
+ifdef ENABLE_SPARC_JIT
+  CPPFLAGS += -DENABLE_SPARC_JIT
+  JITLIBS  += sparc 
+  ARCHLIBS += sched livevar instrument.a profpaths \
+              bcwriter transforms.a ipo.a ipa.a datastructure.a regalloc \
+              select
+endif
+
+USEDLIBS = lli-interpreter $(JITLIBS) $(ARCHLIBS) scalaropts analysis.a \
+           transformutils.a debugger bcreader vmcore support target.a
+
+
+# Have gcc tell the linker to export symbols from the program so that
+# dynamically loaded modules can be linked against them.
+#
+TOOLLINKOPTS = $(PLATFORMLIBDL)
+
+include $(LEVEL)/Makefile.common
+
diff --git a/tools/llvm-db/llvm-db.cpp b/tools/llvm-db/llvm-db.cpp
new file mode 100644
index 0000000000..124db2ba06
--- /dev/null
+++ b/tools/llvm-db/llvm-db.cpp
@@ -0,0 +1,88 @@
+//===- llvm-db.cpp - LLVM Debugger ----------------------------------------===//
+// 
+//                     The LLVM Compiler Infrastructure
+//
+// This file was developed by the LLVM research group and is distributed under
+// the University of Illinois Open Source License. See LICENSE.TXT for details.
+// 
+//===----------------------------------------------------------------------===//
+//
+// This utility implements a simple text-mode front-end to the LLVM debugger
+// library.
+//
+//===----------------------------------------------------------------------===//
+
+#include "CLIDebugger.h"
+#include "Support/CommandLine.h"
+#include <iostream>
+
+using namespace llvm;
+
+namespace {
+  // Command line options for specifying the program to debug and options to use
+  cl::opt<std::string>
+  InputFile(cl::desc("<program>"), cl::Positional, cl::init(""));
+
+  cl::list<std::string>
+  InputArgs("args", cl::Positional, cl::desc("<program and arguments>"),
+            cl::ZeroOrMore);
+
+  // Command line options to control various directory related stuff
+  cl::list<std::string>
+  SourceDirectories("directory", cl::value_desc("directory"),
+                    cl::desc("Add directory to the search for source files"));
+  cl::alias SDA("d", cl::desc("Alias for --directory"),
+                cl::aliasopt(SourceDirectories));
+  
+  cl::opt<std::string>
+  WorkingDirectory("cd", cl::desc("Use directory as current working directory"),
+                   cl::value_desc("directory"));
+
+  // Command line options specific to the llvm-db debugger driver
+  cl::opt<bool> Version("version", cl::desc("Print version number and quit"));
+  cl::opt<bool> Quiet("quiet", cl::desc("Do not print introductory messages"));
+  cl::alias QA1("silent", cl::desc("Alias for -quiet"), cl::aliasopt(Quiet));
+  cl::alias QA2("q", cl::desc("Alias for -quiet"), cl::aliasopt(Quiet));
+}
+
+//===----------------------------------------------------------------------===//
+// main Driver function
+//
+int main(int argc, char **argv, char * const *envp) {
+  cl::ParseCommandLineOptions(argc, argv,
+                              " llvm source-level debugger\n");
+
+  if (Version || !Quiet) {
+    std::cout << "llvm-db: The LLVM source-level debugger\n";
+    if (Version) return 1;
+  }
+
+  // Merge Inputfile and InputArgs into the InputArgs list...
+  if (!InputFile.empty() && InputArgs.empty())
+    InputArgs.push_back(InputFile);
+
+  // Create the CLI debugger...
+  CLIDebugger D;
+
+  // Initialize the debugger with the command line options we read...
+  Debugger &Dbg = D.getDebugger();
+
+  // Initialize the debugger environment.
+  Dbg.initializeEnvironment(envp);
+  Dbg.setWorkingDirectory(WorkingDirectory);
+  for (unsigned i = 0, e = SourceDirectories.size(); i != e; ++i)
+    D.addSourceDirectory(SourceDirectories[i]);
+  
+  if (!InputArgs.empty()) {
+    try {
+      D.fileCommand(InputArgs[0]);
+    } catch (const std::string &Error) {
+      std::cout << "Error: " << Error << "\n";
+    }
+
+    Dbg.setProgramArguments(InputArgs.begin()+1, InputArgs.end());
+  }
+
+  // Now that we have initialized the debugger, run it.
+  return D.run();
+}