1 files changed, 67 insertions, 0 deletions
diff --git a/deps/v8/tools/regexp-sequences.py b/deps/v8/tools/regexp-sequences.py
new file mode 100755
index 0000000000..56e83679a9
--- /dev/null
+++ b/deps/v8/tools/regexp-sequences.py
@@ -0,0 +1,67 @@
+#!/usr/bin/env python
+# Copyright 2019 the V8 project authors. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+"""
+python %prog trace-file
+
+Parses output generated by v8 with flag --trace-regexp-bytecodes and generates
+a list of the most common sequences.
+"""
+
+from __future__ import print_function
+
+import sys
+import re
+import collections
+
+def parse(file, seqlen):
+  # example:
+  # pc = 00, sp = 0, curpos = 0, curchar = 0000000a ..., bc = PUSH_BT, 02, 00, 00, 00, e8, 00, 00, 00 .......
+  rx = re.compile(r'pc = (?P<pc>[0-9a-f]+), sp = (?P<sp>\d+), '
+                  r'curpos = (?P<curpos>\d+), curchar = (?P<char_hex>[0-9a-f]+) '
+                  r'(:?\.|\()(?P<char>\.|\w)(:?\.|\)), bc = (?P<bc>\w+), .*')
+  total = 0
+  bc_cnt = [None] * seqlen
+  for i in xrange(seqlen):
+    bc_cnt[i] = {}
+  last = [None] * seqlen
+  with open(file) as f:
+    l = f.readline()
+    while l:
+      l = l.strip()
+      if l.startswith("Start bytecode interpreter"):
+        for i in xrange(seqlen):
+          last[i] = collections.deque(maxlen=i+1)
+
+      match = rx.search(l)
+      if match:
+        total += 1
+        bc = match.group('bc')
+        for i in xrange(seqlen):
+          last[i].append(bc)
+          key = ' --> '.join(last[i])
+          bc_cnt[i][key] = bc_cnt[i].get(key,0) + 1
+
+      l = f.readline()
+  return bc_cnt, total
+
+def print_most_common(d, seqlen, total):
+  sorted_d = sorted(d.items(), key=lambda kv: kv[1], reverse=True)
+  for (k,v) in sorted_d:
+    if v*100/total < 1.0:
+      return
+    print("{}: {} ({} %)".format(k,v,(v*100/total)))
+
+def main(argv):
+  max_seq = 7
+  bc_cnt, total = parse(argv[1],max_seq)
+  for i in xrange(max_seq):
+    print()
+    print("Most common of length {}".format(i+1))
+    print()
+    print_most_common(bc_cnt[i], i, total)
+
+if __name__ == '__main__':
+  main(sys.argv)