Index: docs/CommandGuide/lit.rst
===================================================================
--- docs/CommandGuide/lit.rst
+++ docs/CommandGuide/lit.rst
@@ -122,6 +122,12 @@
  suite take the most time to execute.  Note that this option is most useful
  with ``-j 1``.
 
+.. option:: --exec-feature=FEATURE
+
+ Specify an additional feature of test execution that can be matched in REQUIRES
+ and XFAIL lines. For example, if you run tests under AddressSanitizer, you can
+ specify ``--exec-feature=asan``.
+ 
 .. _selection-options:
 
 SELECTION OPTIONS
Index: utils/lit/lit/LitConfig.py
===================================================================
--- utils/lit/lit/LitConfig.py
+++ utils/lit/lit/LitConfig.py
@@ -19,7 +19,7 @@
 
     def __init__(self, progname, path, quiet,
                  useValgrind, valgrindLeakCheck, valgrindArgs,
-                 noExecute, ignoreStdErr, debug, isWindows,
+                 noExecute, execFeatures, ignoreStdErr, debug, isWindows,
                  params, config_prefix = None):
         # The name of the test runner.
         self.progname = progname
@@ -30,6 +30,7 @@
         self.valgrindLeakCheck = bool(valgrindLeakCheck)
         self.valgrindUserArgs = list(valgrindArgs)
         self.noExecute = noExecute
+        self.execFeatures = list(execFeatures)
         self.ignoreStdErr = ignoreStdErr
         self.debug = debug
         self.isWindows = bool(isWindows)
@@ -47,10 +48,12 @@
 
         self.valgrindArgs = []
         if self.useValgrind:
+            self.execFeatures.append('valgrind')
             self.valgrindArgs = ['valgrind', '-q', '--run-libc-freeres=no',
                                  '--tool=memcheck', '--trace-children=yes',
                                  '--error-exitcode=123']
             if self.valgrindLeakCheck:
+                self.execFeatures.append('vg_leak')
                 self.valgrindArgs.append('--leak-check=full')
             else:
                 # The default is 'summary'.
Index: utils/lit/lit/TestingConfig.py
===================================================================
--- utils/lit/lit/TestingConfig.py
+++ utils/lit/lit/TestingConfig.py
@@ -29,13 +29,6 @@
                         'TMP' : os.environ.get('TMP',''),
                         })
 
-            # Set the default available features based on the LitConfig.
-            available_features = []
-            if litConfig.useValgrind:
-                available_features.append('valgrind')
-                if litConfig.valgrindLeakCheck:
-                    available_features.append('vg_leak')
-
             config = TestingConfig(parent,
                                    name = '<unnamed>',
                                    suffixes = set(),
@@ -47,7 +40,7 @@
                                    test_exec_root = None,
                                    test_source_root = None,
                                    excludes = [],
-                                   available_features = available_features)
+                                   available_features = litConfig.execFeatures)
 
         if os.path.exists(path):
             # FIXME: Improve detection and error reporting of errors in the
Index: utils/lit/lit/discovery.py
===================================================================
--- utils/lit/lit/discovery.py
+++ utils/lit/lit/discovery.py
@@ -222,6 +222,7 @@
                                     valgrindLeakCheck = False,
                                     valgrindArgs = [],
                                     noExecute = False,
+                                    execFeatures = [],
                                     ignoreStdErr = False,
                                     debug = False,
                                     isWindows = (platform.system()=='Windows'),
Index: utils/lit/lit/main.py
===================================================================
--- utils/lit/lit/main.py
+++ utils/lit/lit/main.py
@@ -207,6 +207,10 @@
     group.add_option("", "--no-execute", dest="noExecute",
                      help="Don't execute any tests (assume PASS)",
                      action="store_true", default=False)
+    group.add_option("", "--exec-feature", dest="execFeatures",
+                     metavar="FEATURE",
+                     help="Add user-defined feature of test execution",
+                     type=str, action="append", default=[])
     parser.add_option_group(group)
 
     group = OptionGroup(parser, "Test Selection")
@@ -271,6 +275,7 @@
                                     valgrindLeakCheck = opts.valgrindLeakCheck,
                                     valgrindArgs = opts.valgrindArgs,
                                     noExecute = opts.noExecute,
+                                    execFeatures = opts.execFeatures,
                                     ignoreStdErr = False,
                                     debug = opts.debug,
                                     isWindows = (platform.system()=='Windows'),