diff --git a/utils/lit/TestRunner.py b/utils/lit/TestRunner.py
new file mode 100644
index 0000000..954013a
--- /dev/null
+++ b/utils/lit/TestRunner.py
@@ -0,0 +1,460 @@
+import os, signal, subprocess, sys
+import StringIO
+
+import ShUtil
+import Test
+import Util
+
+def executeCommand(command, cwd=None, env=None):
+    p = subprocess.Popen(command, cwd=cwd,
+                         stdin=subprocess.PIPE,
+                         stdout=subprocess.PIPE,
+                         stderr=subprocess.PIPE,
+                         env=env)
+    out,err = p.communicate()
+    exitCode = p.wait()
+
+    # Detect Ctrl-C in subprocess.
+    if exitCode == -signal.SIGINT:
+        raise KeyboardInterrupt
+
+    return out, err, exitCode
+
+def executeShCmd(cmd, cfg, cwd, results):
+    if isinstance(cmd, ShUtil.Seq):
+        if cmd.op == ';':
+            res = executeShCmd(cmd.lhs, cfg, cwd, results)
+            return executeShCmd(cmd.rhs, cfg, cwd, results)
+
+        if cmd.op == '&':
+            raise NotImplementedError,"unsupported test command: '&'"
+
+        if cmd.op == '||':
+            res = executeShCmd(cmd.lhs, cfg, cwd, results)
+            if res != 0:
+                res = executeShCmd(cmd.rhs, cfg, cwd, results)
+            return res
+        if cmd.op == '&&':
+            res = executeShCmd(cmd.lhs, cfg, cwd, results)
+            if res is None:
+                return res
+
+            if res == 0:
+                res = executeShCmd(cmd.rhs, cfg, cwd, results)
+            return res
+
+        raise ValueError,'Unknown shell command: %r' % cmd.op
+
+    assert isinstance(cmd, ShUtil.Pipeline)
+    procs = []
+    input = subprocess.PIPE
+    for j in cmd.commands:
+        redirects = [(0,), (1,), (2,)]
+        for r in j.redirects:
+            if r[0] == ('>',2):
+                redirects[2] = [r[1], 'w', None]
+            elif r[0] == ('>&',2) and r[1] in '012':
+                redirects[2] = redirects[int(r[1])]
+            elif r[0] == ('>&',) or r[0] == ('&>',):
+                redirects[1] = redirects[2] = [r[1], 'w', None]
+            elif r[0] == ('>',):
+                redirects[1] = [r[1], 'w', None]
+            elif r[0] == ('<',):
+                redirects[0] = [r[1], 'r', None]
+            else:
+                raise NotImplementedError,"Unsupported redirect: %r" % (r,)
+
+        final_redirects = []
+        for index,r in enumerate(redirects):
+            if r == (0,):
+                result = input
+            elif r == (1,):
+                if index == 0:
+                    raise NotImplementedError,"Unsupported redirect for stdin"
+                elif index == 1:
+                    result = subprocess.PIPE
+                else:
+                    result = subprocess.STDOUT
+            elif r == (2,):
+                if index != 2:
+                    raise NotImplementedError,"Unsupported redirect on stdout"
+                result = subprocess.PIPE
+            else:
+                if r[2] is None:
+                    r[2] = open(r[0], r[1])
+                result = r[2]
+            final_redirects.append(result)
+
+        stdin, stdout, stderr = final_redirects
+
+        # If stderr wants to come from stdout, but stdout isn't a pipe, then put
+        # stderr on a pipe and treat it as stdout.
+        if (stderr == subprocess.STDOUT and stdout != subprocess.PIPE):
+            stderr = subprocess.PIPE
+            stderrIsStdout = True
+        else:
+            stderrIsStdout = False
+        procs.append(subprocess.Popen(j.args, cwd=cwd,
+                                      stdin = stdin,
+                                      stdout = stdout,
+                                      stderr = stderr,
+                                      env = cfg.environment,
+                                      close_fds = True))
+
+        # Immediately close stdin for any process taking stdin from us.
+        if stdin == subprocess.PIPE:
+            procs[-1].stdin.close()
+            procs[-1].stdin = None
+
+        # Update the current stdin source.
+        if stdout == subprocess.PIPE:
+            input = procs[-1].stdout
+        elif stderrIsStdout:
+            input = procs[-1].stderr
+        else:
+            input = subprocess.PIPE
+
+    # FIXME: There is a potential for deadlock here, when we have a pipe and
+    # some process other than the last one ends up blocked on stderr.
+    procData = [None] * len(procs)
+    procData[-1] = procs[-1].communicate()
+    for i in range(len(procs) - 1):
+        if procs[i].stdout is not None:
+            out = procs[i].stdout.read()
+        else:
+            out = ''
+        if procs[i].stderr is not None:
+            err = procs[i].stderr.read()
+        else:
+            err = ''
+        procData[i] = (out,err)
+
+    exitCode = None
+    for i,(out,err) in enumerate(procData):
+        res = procs[i].wait()
+        # Detect Ctrl-C in subprocess.
+        if res == -signal.SIGINT:
+            raise KeyboardInterrupt
+
+        results.append((cmd.commands[i], out, err, res))
+        if cmd.pipe_err:
+            # Python treats the exit code as a signed char.
+            if res < 0:
+                exitCode = min(exitCode, res)
+            else:
+                exitCode = max(exitCode, res)
+        else:
+            exitCode = res
+
+    if cmd.negate:
+        exitCode = not exitCode
+
+    return exitCode
+
+def executeScriptInternal(test, litConfig, tmpBase, commands, cwd):
+    ln = ' &&\n'.join(commands)
+    try:
+        cmd = ShUtil.ShParser(ln, litConfig.isWindows).parse()
+    except:
+        return (Test.FAIL, "shell parser error on: %r" % ln)
+
+    results = []
+    exitCode = executeShCmd(cmd, test.config, cwd, results)
+
+    out = err = ''
+    for i,(cmd, cmd_out,cmd_err,res) in enumerate(results):
+        out += 'Command %d: %s\n' % (i, ' '.join('"%s"' % s for s in cmd.args))
+        out += 'Command %d Result: %r\n' % (i, res)
+        out += 'Command %d Output:\n%s\n\n' % (i, cmd_out)
+        out += 'Command %d Stderr:\n%s\n\n' % (i, cmd_err)
+
+    return out, err, exitCode
+
+def executeTclScriptInternal(test, litConfig, tmpBase, commands, cwd):
+    import TclUtil
+    cmds = []
+    for ln in commands:
+        # Given the unfortunate way LLVM's test are written, the line gets
+        # backslash substitution done twice.
+        ln = TclUtil.TclLexer(ln).lex_unquoted(process_all = True)
+
+        try:
+            tokens = list(TclUtil.TclLexer(ln).lex())
+        except:
+            return (Test.FAIL, "Tcl lexer error on: %r" % ln)
+
+        # Validate there are no control tokens.
+        for t in tokens:
+            if not isinstance(t, str):
+                return (Test.FAIL,
+                        "Invalid test line: %r containing %r" % (ln, t))
+
+        try:
+            cmds.append(TclUtil.TclExecCommand(tokens).parse_pipeline())
+        except:
+            return (TestStatus.Fail, "Tcl 'exec' parse error on: %r" % ln)
+
+    cmd = cmds[0]
+    for c in cmds[1:]:
+        cmd = ShUtil.Seq(cmd, '&&', c)
+
+    if litConfig.useTclAsSh:
+        script = tmpBase + '.script'
+
+        # Write script file
+        f = open(script,'w')
+        print >>f, 'set -o pipefail'
+        cmd.toShell(f, pipefail = True)
+        f.close()
+
+        if 0:
+            print >>sys.stdout, cmd
+            print >>sys.stdout, open(script).read()
+            print >>sys.stdout
+            return '', '', 0
+
+        command = ['/bin/sh', script]
+        out,err,exitCode = executeCommand(command, cwd=cwd,
+                                          env=test.config.environment)
+
+        # Tcl commands fail on standard error output.
+        if err:
+            exitCode = 1
+            out = 'Command has output on stderr!\n\n' + out
+
+        return out,err,exitCode
+    else:
+        results = []
+        exitCode = executeShCmd(cmd, test.config, cwd, results)
+
+    out = err = ''
+
+    # Tcl commands fail on standard error output.
+    if [True for _,_,err,res in results if err]:
+        exitCode = 1
+        out += 'Command has output on stderr!\n\n'
+
+    for i,(cmd, cmd_out, cmd_err, res) in enumerate(results):
+        out += 'Command %d: %s\n' % (i, ' '.join('"%s"' % s for s in cmd.args))
+        out += 'Command %d Result: %r\n' % (i, res)
+        out += 'Command %d Output:\n%s\n\n' % (i, cmd_out)
+        out += 'Command %d Stderr:\n%s\n\n' % (i, cmd_err)
+
+    return out, err, exitCode
+
+def executeScript(test, litConfig, tmpBase, commands, cwd):
+    script = tmpBase + '.script'
+    if litConfig.isWindows:
+        script += '.bat'
+
+    # Write script file
+    f = open(script,'w')
+    if litConfig.isWindows:
+        f.write('\nif %ERRORLEVEL% NEQ 0 EXIT\n'.join(commands))
+    else:
+        f.write(' &&\n'.join(commands))
+    f.write('\n')
+    f.close()
+
+    if litConfig.isWindows:
+        command = ['cmd','/c', script]
+    else:
+        command = ['/bin/sh', script]
+        if litConfig.useValgrind:
+            # FIXME: Running valgrind on sh is overkill. We probably could just
+            # run on clang with no real loss.
+            valgrindArgs = ['valgrind', '-q',
+                            '--tool=memcheck', '--trace-children=yes',
+                            '--error-exitcode=123']
+            valgrindArgs.extend(litConfig.valgrindArgs)
+
+            command = valgrindArgs + command
+
+    return executeCommand(command, cwd=cwd, env=test.config.environment)
+
+def parseIntegratedTestScript(test, xfailHasColon, requireAndAnd):
+    """parseIntegratedTestScript - Scan an LLVM/Clang style integrated test
+    script and extract the lines to 'RUN' as well as 'XFAIL' and 'XTARGET'
+    information. The RUN lines also will have variable substitution performed.
+    """
+
+    # Get the temporary location, this is always relative to the test suite
+    # root, not test source root.
+    #
+    # FIXME: This should not be here?
+    sourcepath = test.getSourcePath()
+    execpath = test.getExecPath()
+    execdir,execbase = os.path.split(execpath)
+    tmpBase = os.path.join(execdir, 'Output', execbase)
+
+    # We use #_MARKER_# to hide %% while we do the other substitutions.
+    substitutions = [('%%', '#_MARKER_#')]
+    substitutions.extend(test.config.substitutions)
+    substitutions.extend([('%s', sourcepath),
+                          ('%S', os.path.dirname(sourcepath)),
+                          ('%p', os.path.dirname(sourcepath)),
+                          ('%t', tmpBase + '.tmp'),
+                          ('#_MARKER_#', '%')])
+
+    # Collect the test lines from the script.
+    script = []
+    xfails = []
+    xtargets = []
+    for ln in open(sourcepath):
+        if 'RUN:' in ln:
+            # Isolate the command to run.
+            index = ln.index('RUN:')
+            ln = ln[index+4:]
+
+            # Trim trailing whitespace.
+            ln = ln.rstrip()
+
+            # Collapse lines with trailing '\\'.
+            if script and script[-1][-1] == '\\':
+                script[-1] = script[-1][:-1] + ln
+            else:
+                script.append(ln)
+        elif xfailHasColon and 'XFAIL:' in ln:
+            items = ln[ln.index('XFAIL:') + 6:].split(',')
+            xfails.extend([s.strip() for s in items])
+        elif not xfailHasColon and 'XFAIL' in ln:
+            items = ln[ln.index('XFAIL') + 5:].split(',')
+            xfails.extend([s.strip() for s in items])
+        elif 'XTARGET:' in ln:
+            items = ln[ln.index('XTARGET:') + 8:].split(',')
+            xtargets.extend([s.strip() for s in items])
+        elif 'END.' in ln:
+            # Check for END. lines.
+            if ln[ln.index('END.'):].strip() == 'END.':
+                break
+
+    # Apply substitutions to the script.
+    def processLine(ln):
+        # Apply substitutions
+        for a,b in substitutions:
+            ln = ln.replace(a,b)
+
+        # Strip the trailing newline and any extra whitespace.
+        return ln.strip()
+    script = map(processLine, script)
+
+    # Verify the script contains a run line.
+    if not script:
+        return (Test.UNRESOLVED, "Test has no run line!")
+
+    if script[-1][-1] == '\\':
+        return (Test.UNRESOLVED, "Test has unterminated run lines (with '\\')")
+
+    # Validate interior lines for '&&', a lovely historical artifact.
+    if requireAndAnd:
+        for i in range(len(script) - 1):
+            ln = script[i]
+
+            if not ln.endswith('&&'):
+                return (Test.FAIL,
+                        ("MISSING \'&&\': %s\n"  +
+                         "FOLLOWED BY   : %s\n") % (ln, script[i + 1]))
+
+            # Strip off '&&'
+            script[i] = ln[:-2]
+
+    return script,xfails,xtargets,tmpBase,execdir
+
+def formatTestOutput(status, out, err, exitCode, script):
+    output = StringIO.StringIO()
+    print >>output, "Script:"
+    print >>output, "--"
+    print >>output, '\n'.join(script)
+    print >>output, "--"
+    print >>output, "Exit Code: %r" % exitCode
+    print >>output, "Command Output (stdout):"
+    print >>output, "--"
+    output.write(out)
+    print >>output, "--"
+    print >>output, "Command Output (stderr):"
+    print >>output, "--"
+    output.write(err)
+    print >>output, "--"
+    return (status, output.getvalue())
+
+def executeTclTest(test, litConfig):
+    if test.config.unsupported:
+        return (Test.UNSUPPORTED, 'Test is unsupported')
+
+    res = parseIntegratedTestScript(test, True, False)
+    if len(res) == 2:
+        return res
+
+    script, xfails, xtargets, tmpBase, execdir = res
+
+    if litConfig.noExecute:
+        return (Test.PASS, '')
+
+    # Create the output directory if it does not already exist.
+    Util.mkdir_p(os.path.dirname(tmpBase))
+
+    res = executeTclScriptInternal(test, litConfig, tmpBase, script, execdir)
+    if len(res) == 2:
+        return res
+
+    isXFail = False
+    for item in xfails:
+        if item == '*' or item in test.suite.config.target_triple:
+            isXFail = True
+            break
+
+    # If this is XFAIL, see if it is expected to pass on this target.
+    if isXFail:
+        for item in xtargets:
+            if item == '*' or item in test.suite.config.target_triple:
+                isXFail = False
+                break
+
+    out,err,exitCode = res
+    if isXFail:
+        ok = exitCode != 0
+        status = (Test.XPASS, Test.XFAIL)[ok]
+    else:
+        ok = exitCode == 0
+        status = (Test.FAIL, Test.PASS)[ok]
+
+    if ok:
+        return (status,'')
+
+    return formatTestOutput(status, out, err, exitCode, script)
+
+def executeShTest(test, litConfig, useExternalSh, requireAndAnd):
+    if test.config.unsupported:
+        return (Test.UNSUPPORTED, 'Test is unsupported')
+
+    res = parseIntegratedTestScript(test, False, requireAndAnd)
+    if len(res) == 2:
+        return res
+
+    script, xfails, xtargets, tmpBase, execdir = res
+
+    if litConfig.noExecute:
+        return (Test.PASS, '')
+
+    # Create the output directory if it does not already exist.
+    Util.mkdir_p(os.path.dirname(tmpBase))
+
+    if useExternalSh:
+        res = executeScript(test, litConfig, tmpBase, script, execdir)
+    else:
+        res = executeScriptInternal(test, litConfig, tmpBase, script, execdir)
+    if len(res) == 2:
+        return res
+
+    out,err,exitCode = res
+    if xfails:
+        ok = exitCode != 0
+        status = (Test.XPASS, Test.XFAIL)[ok]
+    else:
+        ok = exitCode == 0
+        status = (Test.FAIL, Test.PASS)[ok]
+
+    if ok:
+        return (status,'')
+
+    return formatTestOutput(status, out, err, exitCode, script)