diff --git a/llvm/utils/lit/lit/ShCommands.py b/llvm/utils/lit/lit/ShCommands.py
--- a/llvm/utils/lit/lit/ShCommands.py
+++ b/llvm/utils/lit/lit/ShCommands.py
@@ -43,20 +43,36 @@
         return self.pattern
 
     def __eq__(self, other):
-        if not isinstance(other, Command):
+        if not isinstance(other, GlobItem):
             return False
 
         return (self.pattern == other.pattern)
 
     def resolve(self, cwd):
         import glob
+        import platform
         import os
         if os.path.isabs(self.pattern):
            abspath = self.pattern
         else:
             abspath = os.path.join(cwd, self.pattern)
+
+        # To get better behavior with long paths, we prepend the magic
+        # prefix to make Windows API allow up to 32K bytes in the paths.
+        # However, this only works in 2.7.16 and above because of
+        # https://bugs.python.org/issue32539
+        use_prefix = (platform.system() == 'Windows' and
+                      platform.python_version_tuple() >= (2, 7, 16))
+        if use_prefix:
+            abspath = u'\\\\?\\' + os.path.normpath(abspath)
+
         results = glob.glob(abspath)
-        return [self.pattern] if len(results) == 0 else results
+        if len(results) == 0:
+            return [self.pattern]
+        elif use_prefix:
+            return [result[4:] for result in results]
+        else:
+            return results
 
 class Pipeline:
     def __init__(self, commands, negate=False, pipe_err=False):
diff --git a/llvm/utils/lit/tests/unit/GlobItem.py b/llvm/utils/lit/tests/unit/GlobItem.py
new file mode 100644
--- /dev/null
+++ b/llvm/utils/lit/tests/unit/GlobItem.py
@@ -0,0 +1,73 @@
+# RUN: %{python} %s
+
+import os
+import platform
+import shutil
+import tempfile
+import unittest
+
+from lit.ShCommands import GlobItem
+
+
+class TestGlobItem(unittest.TestCase):
+    def setUp(self):
+        self.test_dir = tempfile.mkdtemp()
+
+    def tearDown(self):
+        # We might be deleting long paths, so rmtree has to be started with a
+        # long path prefix, even if it is not one.
+        if platform.system() == 'Windows':
+            shutil.rmtree(u'\\\\?\\' + self.test_dir)
+        else:
+            shutil.rmtree(self.test_dir)
+        pass
+
+    def test_short_path(self):
+        file_name = 'bbbbbbbb.ccc' # Classic 8.3 file name
+        # 260 is the maximum Windows path length in many cases.
+        # 50 is under the limit.
+        dir_name_len = 50
+        dir_name = 'a' * dir_name_len
+        dir_abs_path = os.path.join(self.test_dir, dir_name)
+        file_abs_path = os.path.join(dir_abs_path, file_name)
+
+        os.makedirs(dir_abs_path)
+        with open(file_abs_path, 'wb') as f:
+            f.write('test')
+
+        glob_item = GlobItem(os.path.join(dir_abs_path, '*'))
+        result = glob_item.resolve(os.getcwd())
+        self.assertEqual(result, [file_abs_path])
+
+    def test_long_path(self):
+        file_name = 'bbbbbbbb.ccc' # Classic 8.3 file name
+        # 260 is the maximum Windows path length in many cases.
+        # 250 should be over the limit, but also under the limit for directory
+        # name length in Windows.
+        dir_name_len = 250
+        dir_name = 'a' * dir_name_len
+        dir_abs_path = os.path.join(self.test_dir, dir_name)
+        file_abs_path = os.path.join(dir_abs_path, file_name)
+
+        # In Windows we have to use the \\?\ prefix or these calls will fail
+        # during the test setup.
+        def prefix_path_in_windows(path):
+            if platform.system() == 'Windows':
+                return u'\\\\?\\' + path
+            else:
+                return path
+
+        os.makedirs(prefix_path_in_windows(dir_abs_path))
+        with open(prefix_path_in_windows(file_abs_path), 'wb') as f:
+            f.write('test')
+
+        # Do NOT use prefix_path_in_windows here. We are testing that GlobItem
+        # does the right thing.
+        glob_item = GlobItem(os.path.join(dir_abs_path, '*'))
+        result = glob_item.resolve(os.getcwd())
+        self.assertEqual(result, [file_abs_path])
+
+
+
+if __name__ == '__main__':
+    unittest.main()
\ No newline at end of file