Index: docs/TestingGuide.rst
===================================================================
--- docs/TestingGuide.rst
+++ docs/TestingGuide.rst
@@ -506,6 +506,9 @@
 ``%clang_cc1``
    Invokes the Clang frontend.
 
+``%clang_analyze_cc1``
+   Invokes the Clang frontend with the static analyzer.
+
 ``%itanium_abi_triple``, ``%ms_abi_triple``
    These substitutions can be used to get the current target triple adjusted to
    the desired ABI. For example, if the test suite is running with the
Index: utils/lit/lit/TestRunner.py
===================================================================
--- utils/lit/lit/TestRunner.py
+++ utils/lit/lit/TestRunner.py
@@ -1045,6 +1045,8 @@
     if hasattr(test.config, 'test_retry_attempts'):
         attempts += test.config.test_retry_attempts
     for i in range(attempts):
+        if "ShTest" in test.config.callbacks:
+            script = test.config.callbacks["ShTest"](test, script)
         res = _runShTest(test, litConfig, useExternalSh, script, tmpBase)
         if res.code != Test.FAIL:
             break
Index: utils/lit/lit/TestingConfig.py
===================================================================
--- utils/lit/lit/TestingConfig.py
+++ utils/lit/lit/TestingConfig.py
@@ -106,7 +106,7 @@
                  environment, substitutions, unsupported,
                  test_exec_root, test_source_root, excludes,
                  available_features, pipefail, limit_to_features = [],
-                 is_early = False, parallelism_group = ""):
+                 is_early = False, parallelism_group = "", callbacks = {}):
         self.parent = parent
         self.name = str(name)
         self.suffixes = set(suffixes)
@@ -126,6 +126,7 @@
         # Whether the suite should be tested early in a given run.
         self.is_early = bool(is_early)
         self.parallelism_group = parallelism_group
+        self.callbacks = callbacks
 
     def finish(self, litConfig):
         """finish() - Finish this config object, after loading is complete."""
@@ -143,6 +144,7 @@
             # files. Should we distinguish them?
             self.test_source_root = str(self.test_source_root)
         self.excludes = set(self.excludes)
+        self.callbacks = dict(self.callbacks)
 
     @property
     def root(self):
Index: utils/lit/tests/Inputs/shtest-callback/lit.cfg
===================================================================
--- /dev/null
+++ utils/lit/tests/Inputs/shtest-callback/lit.cfg
@@ -0,0 +1,8 @@
+import lit.formats
+config.name = 'shtest-callback'
+config.substitutions = [('%callback1', '%callback2')]
+config.suffixes = ['.txt']
+config.test_format = lit.formats.ShTest()
+config.test_source_root = None
+config.test_exec_root = None
+config.target_triple = 'x86_64-unknown-unknown'
Index: utils/lit/tests/Inputs/shtest-callback/lit.local.cfg
===================================================================
--- /dev/null
+++ utils/lit/tests/Inputs/shtest-callback/lit.local.cfg
@@ -0,0 +1,7 @@
+import lit.TestRunner
+
+def callback(test, cmd):
+    return lit.TestRunner.applySubstitutions(cmd, [('%callback2', 'true')])
+
+config.callbacks["ShTest"] = callback
+
Index: utils/lit/tests/Inputs/shtest-callback/shtest.txt
===================================================================
--- /dev/null
+++ utils/lit/tests/Inputs/shtest-callback/shtest.txt
@@ -0,0 +1 @@
+# RUN: %callback1
Index: utils/lit/tests/shtest-callback.py
===================================================================
--- /dev/null
+++ utils/lit/tests/shtest-callback.py
@@ -0,0 +1,8 @@
+# Test callbacks are executed correctly.
+
+# RUN: %{lit} -j 1 -v %{inputs}/callback > %t.out
+# RUN: FileCheck < %t.out %s
+
+# CHECK: -- Testing:
+
+# CHECK: PASS: callback :: shtest.txt