[opt-viewer] Make filter_=None by default in get_remarks and gather_results

[paquette]

Summary

Right now, if you try to use optdiff.py on any opt records, it will fail because its calls to gather_results weren't updated to support filtering.

Since filters are supposed to be optional, this makes them None by default in get_remarks and in gather_results. This allows other tools that don't support filtering to still use the functions as is.

[anemet]

LGTM, thanks for fixing this!

llvm/trunk/tools/opt-viewer/optrecord.py

 class Missed(Remark):
     yaml_tag = '!Missed'
 
     @property
     def color(self):
         return "red"
 
 
-def get_remarks(input_file, filter_):
+def get_remarks(input_file, filter_=None):
     max_hotness = 0
     all_remarks = dict()
     file_remarks = defaultdict(functools.partial(defaultdict, list))
 
     with open(input_file) as f:
         docs = yaml.load_all(f, Loader=Loader)
 
+        filter_e = None
+        if filter_:
             filter_e = re.compile(filter_)
         for remark in docs:
             remark.canonicalize()
             # Avoid remarks withoug debug location or if they are duplicated
             if not hasattr(remark, 'DebugLoc') or remark.key in all_remarks:
                 continue
 
-            if filter_ and not filter_e.search(remark.Pass):
+            if filter_e and not filter_e.search(remark.Pass):
                 continue
 
             all_remarks[remark.key] = remark
 
             file_remarks[remark.File][remark.Line].append(remark)
 
             # If we're reading a back a diff yaml file, max_hotness is already
             # captured which may actually be less than the max hotness found
             # in the file.
             if hasattr(remark, 'max_hotness'):
                 max_hotness = remark.max_hotness
             max_hotness = max(max_hotness, remark.Hotness)
 
     return max_hotness, all_remarks, file_remarks
 
 
-def gather_results(filenames, num_jobs, should_print_progress, filter_):
+def gather_results(filenames, num_jobs, should_print_progress, filter_=None):
     if should_print_progress:
         print('Reading YAML files...')
     if not Remark.demangler_proc:
         Remark.set_demangler(Remark.default_demangler)
     remarks = optpmap.pmap(
         get_remarks, filenames, num_jobs, should_print_progress, filter_)
     max_hotness = max(entry[0] for entry in remarks)