Escape '{' '}' brackets in original command line (#170)

It's possible the original command line has brackets that otherwise
python string formatting will interpret as part of the worker
contextualization formatting (i.e. LoadedModuleSpec.build_command_line).
We need to escape such brackets upfront when loading the command line.

Author: mtrofin

compiler_opt/rl/corpus.py

@@ -315,7 +315,8 @@ def get_cmdline(name: str):
         ret = cmd_override
       else:
         with tf.io.gfile.GFile(os.path.join(data_path, name + '.cmd')) as f:
-          ret = tuple(f.read().split('\0'))
+          ret = tuple(f.read().replace(r'{', r'{{').replace(r'}',
+                                                            r'}}').split('\0'))
           # The options read from a .cmd file must be run with -cc1
           if ret[0] != '-cc1':
             raise ValueError('-cc1 flag not present in .cmd file.')

compiler_opt/rl/corpus_test.py

@@ -178,6 +178,21 @@ def test_ctor_thinlto(self):
                      ('-x', 'ir', '{context.module_full_path}', '-mllvm',
                       '-thinlto-assume-merged'))
 
+  def test_braces_in_cmd(self):
+    corpusdir = self.create_tempdir()
+    cps = corpus.create_corpus_for_testing(
+        location=corpusdir,
+        elements=[corpus.ModuleSpec(name='somename', size=1)],
+        cmdline=('-cc1', r'-DMACRO(expr)=do {} while(0)'),
+        additional_flags=('-additional_flag={context.module_full_path}',))
+    mod_spec = cps.module_specs[0]
+    loaded_spec = cps.load_module_spec(mod_spec)
+    final_cmdline = loaded_spec.build_command_line('some/temp/dir')
+    self.assertEqual(final_cmdline,
+                     ('-cc1', r'-DMACRO(expr)=do {} while(0)', '-x', 'ir',
+                      'some/temp/dir/somename/input.bc',
+                      '-additional_flag=some/temp/dir/somename/input.bc'))
+
   def test_cmd_override_thinlto(self):
     cps = corpus.create_corpus_for_testing(
         location=self.create_tempdir(),