[foozzie] Fix failure state for non-existing source output

BUG=chromium:673246
NOTRY=true
TBR=tandrii@chromium.org,mbarbella@chromium.org

Review-Url: https://codereview.chromium.org/2632623002
Cr-Commit-Position: refs/heads/master@{#42306}

tools/foozzie/v8_foozzie.py

@@ -8,7 +8,6 @@ V8 correctness fuzzer launcher script.
 """
 
 import argparse
-import hashlib
 import itertools
 import json
 import os
@@ -37,10 +36,6 @@ TIMEOUT = 3
 RETURN_PASS = 0
 RETURN_FAIL = 2
 
-# The number of hex digits used from the hash of the original source file path.
-# Keep the number small to avoid duplicate explosion.
-SOURCE_HASH_LENGTH = 3
-
 BASE_PATH = os.path.dirname(os.path.abspath(__file__))
 PREAMBLE = [
   os.path.join(BASE_PATH, 'v8_mock.js'),
@@ -248,7 +243,7 @@ def main():
   if fail_bailout(second_config_output, suppress.ignore_by_output2):
     return RETURN_FAIL
 
-  difference, source = suppress.diff(
+  difference, source_key = suppress.diff(
       first_config_output.stdout, second_config_output.stdout)
   if difference:
     # The first three entries will be parsed by clusterfuzz. Format changes
@@ -257,7 +252,7 @@ def main():
     second_config_label = '%s,%s' % (options.second_arch, options.second_config)
     print FAILURE_TEMPLATE % dict(
         configs='%s:%s' % (first_config_label, second_config_label),
-        sources=hashlib.sha1(source).hexdigest()[:SOURCE_HASH_LENGTH],
+        sources=source_key,
         suppression='', # We can't tie bugs to differences.
         first_config_label=first_config_label,
         second_config_label=second_config_label,

tools/foozzie/v8_suppressions.py

@@ -24,6 +24,7 @@ Alternatively, think about adding a behavior change to v8_suppressions.js
 to silence a particular class of problems.
 """
 
+import hashlib
 import itertools
 import re
 
@@ -148,6 +149,10 @@ IGNORE_LINES = [
 ALLOWED_LINE_DIFFS = [re.compile(exp) for exp in ALLOWED_LINE_DIFFS]
 IGNORE_LINES = [re.compile(exp) for exp in IGNORE_LINES]
 
+# The number of hex digits used from the hash of the original source file path.
+# Keep the number small to avoid duplicate explosion.
+SOURCE_HASH_LENGTH = 3
+
 ORIGINAL_SOURCE_PREFIX = 'v8-foozzie source: '
 
 def line_pairs(lines):
@@ -186,13 +191,13 @@ def ignore_by_regexp(line1, line2, allowed):
 
 
 def diff_output(output1, output2, allowed, ignore1, ignore2):
-  """Returns a tuple (difference, source).
+  """Returns a tuple (difference, source_key).
 
   The difference is None if there's no difference, otherwise a string
   with a readable diff.
 
-  The source is a string with the last source output within the test case.
-  It is the string 'none' if no such output existed.
+  The source_key is a short hash of the last source output within the test
+  case. It is the string 'none' if no such output existed.
   """
   def useful_line(ignore):
     def fun(line):
@@ -204,7 +209,7 @@ def diff_output(output1, output2, allowed, ignore1, ignore2):
 
   # This keeps track where we are in the original source file of the fuzz
   # test case.
-  source = 'none'
+  source_key = 'none'
 
   for ((line1, lookahead1), (line2, lookahead2)) in itertools.izip_longest(
       line_pairs(lines1), line_pairs(lines2), fillvalue=(None, None)):
@@ -214,9 +219,9 @@ def diff_output(output1, output2, allowed, ignore1, ignore2):
 
     # One iterator ends earlier.
     if line1 is None:
-      return '+ %s' % short_line_output(line2), source
+      return '+ %s' % short_line_output(line2), source_key
     if line2 is None:
-      return '- %s' % short_line_output(line1), source
+      return '- %s' % short_line_output(line1), source_key
 
     # If lines are equal, no further checks are necessary.
     if line1 == line2:
@@ -225,6 +230,7 @@ def diff_output(output1, output2, allowed, ignore1, ignore2):
       # are equal.
       if line1.startswith(ORIGINAL_SOURCE_PREFIX):
         source = line1[len(ORIGINAL_SOURCE_PREFIX):]
+        source_key = hashlib.sha1(source).hexdigest()[:SOURCE_HASH_LENGTH]
       continue
 
     # Look ahead. If next line is a caret, ignore this line.
@@ -238,11 +244,11 @@ def diff_output(output1, output2, allowed, ignore1, ignore2):
     # Lines are different.
     return (
         '- %s\n+ %s' % (short_line_output(line1), short_line_output(line2)),
-        source,
+        source_key,
     )
 
   # No difference found.
-  return None, source
+  return None, source_key
 
 
 def get_suppression(arch1, config1, arch2, config2):