Fix lit/example/many-tests pickling issue

[lanza]

Summary

The multiprocess module uses pickling to transfer
information between processes and does not know how to pickle
the class created in the lit.cfg file and thus the example
fails.

Implement ManyTests in a separate file and import for the
example test passes

[lanza]

Running this test fails due to pickle not being able to find the class given that it's created via exec(compile(str_version_of_file)):

cd llvm/utils/lit
./lit.py examples/many-tests

fails with a pickle error. This fixes it.

[sas]

LGTM but there's a small nit inline.

utils/lit/examples/many-tests/ManyTests.py

15

You should leave this blank line in place.

[lanza]

format

[lanza]

@xiaobai Could you land this?

utils/lit/examples/many-tests/ManyTests.py

-# -*- Python -*-
-
 from lit import Test
 
 class ManyTests(object):
     def __init__(self, N=10000):
         self.N = N
 
     def getTestsInDirectory(self, testSuite, path_in_suite,
                             litConfig, localConfig):
         for i in range(self.N):
             test_name = 'test-%04d' % (i,)
             yield Test.Test(testSuite, path_in_suite + (test_name,),
                             localConfig)
-
     def execute(self, test, litConfig):
         # Do a "non-trivial" amount of Python work.
         sum = 0
         for i in range(10000):
             sum += i
         return Test.PASS,''
-
-config.test_format = ManyTests()

utils/lit/examples/many-tests/lit.cfg

 # -*- Python -*-
 
-from lit import Test
+import sys
+import os
+sys.path.insert(0, os.path.dirname(__file__))
+import ManyTests
 
-class ManyTests(object):
-    def __init__(self, N=10000):
-        self.N = N
-
-    def getTestsInDirectory(self, testSuite, path_in_suite,
-                            litConfig, localConfig):
-        for i in range(self.N):
-            test_name = 'test-%04d' % (i,)
-            yield Test.Test(testSuite, path_in_suite + (test_name,),
-                            localConfig)
-
-    def execute(self, test, litConfig):
-        # Do a "non-trivial" amount of Python work.
-        sum = 0
-        for i in range(10000):
-            sum += i
-        return Test.PASS,''
-
-config.test_format = ManyTests()
+config.test_format = ManyTests.ManyTests()