[UpdateTestChecks] Update tests option

Summary:
Port of new feature introduced https://reviews.llvm.org/D65610 to other update scripts.

- update_*_checks.py: add an alias -u for --update-only
- port --update-only to other update_*_test_checks.py scripts
- update script aborts if the test file was generated by another update_*_test_checks.py utility

Reviewers: lebedev.ri, RKSimon, MaskRay, reames, gbedwell

Reviewed By: MaskRay

Subscribers: llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D65793

llvm-svn: 368174
diff --git a/llvm/utils/update_cc_test_checks.py b/llvm/utils/update_cc_test_checks.py
index 205b576..d4eb9f2 100755
--- a/llvm/utils/update_cc_test_checks.py
+++ b/llvm/utils/update_cc_test_checks.py
@@ -86,6 +86,8 @@
   parser.add_argument(
       '--x86_extra_scrub', action='store_true',
       help='Use more regex for x86 matching to reduce diffs between various subtargets')
+  parser.add_argument('-u', '--update-only', action='store_true',
+                      help='Only update test if it was already autogened')
   parser.add_argument('tests', nargs='+')
   args = parser.parse_args()
   args.clang_args = shlex.split(args.clang_args or '')
@@ -126,11 +128,22 @@
 
 def main():
   args = config()
-  autogenerated_note = (ADVERT + 'utils/' + os.path.basename(__file__))
+  script_name = os.path.basename(__file__)
+  autogenerated_note = (ADVERT + 'utils/' + script_name)
 
   for filename in args.tests:
     with open(filename) as f:
       input_lines = [l.rstrip() for l in f]
+    
+    first_line = input_lines[0] if input_lines else ""
+    if 'autogenerated' in first_line and script_name not in first_line:
+      common.warn("Skipping test which wasn't autogenerated by " + script_name, filename)
+      continue
+
+    if args.update_only:
+      if not first_line or 'autogenerated' not in first_line:
+        common.warn("Skipping test which isn't autogenerated: " + filename)
+        continue
 
     # Extract RUN lines.
     raw_lines = [m.group(1)