Add FLAG_trace_maps

tools/trace-maps-processor.py

Index: tools/trace-maps-processor.py
diff --git a/tools/trace-maps-processor.py b/tools/trace-maps-processor.py
new file mode 100755
index 0000000000000000000000000000000000000000..bf8c8a8c926b94c5d93976534b9c044619762292
--- /dev/null
+++ b/tools/trace-maps-processor.py
@@ -0,0 +1,172 @@
+#!/usr/bin/env python
+# Copyright 2014 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.
+
+import sys
+
+
+action = sys.argv[1]
+
+if action in ["help", "-h", "--help"] or len(sys.argv) != 3:
+  print("Usage: %s <action> <inputfile>, where action can be: \n"
+        "help    Print this message\n"
+        "plain   Print ASCII tree to stdout\n"
+        "dot     Print dot file to stdout\n"
+        "count   Count most frequent transition reasons\n" % sys.argv[0])
+  sys.exit(0)
+
+
+filename = sys.argv[2]
+maps = {}
+root_maps = []
+transitions = {}
+annotations = {}
+
+
+class Map(object):
+
+  def __init__(self, pointer, origin):
+    self.pointer = pointer
+    self.origin = origin
+
+  def __str__(self):
+    return "%s (%s)" % (self.pointer, self.origin)
+
+
+class Transition(object):
+
+  def __init__(self, from_map, to_map, reason):
+    self.from_map = from_map
+    self.to_map = to_map
+    self.reason = reason
+
+
+def RegisterNewMap(raw_map):
+  if raw_map in annotations:
+    annotations[raw_map] += 1
+  else:
+    annotations[raw_map] = 0
+  return AnnotateExistingMap(raw_map)
+
+
+def AnnotateExistingMap(raw_map):
+  return "%s_%d" % (raw_map, annotations[raw_map])
+
+
+def AddMap(pointer, origin):
+  pointer = RegisterNewMap(pointer)
+  maps[pointer] = Map(pointer, origin)
+  return pointer
+
+
+def AddTransition(from_map, to_map, reason):
+  from_map = AnnotateExistingMap(from_map)
+  to_map = AnnotateExistingMap(to_map)
+  if from_map not in transitions:
+    transitions[from_map] = {}
+  targets = transitions[from_map]
+  if to_map in targets:
+    # Some events get printed twice, that's OK. In some cases, ignore the
+    # second output...
+    old_reason = targets[to_map].reason
+    if old_reason.startswith("ReplaceDescriptors"):
+      return
+    # ...and in others use it for additional detail.
+    if reason in []:
+      targets[to_map].reason = reason
+      return
+    # Unexpected duplicate events? Warn.
+    print("// warning: already have a transition from %s to %s, reason: %s" %
+            (from_map, to_map, targets[to_map].reason))
+    return
+  targets[to_map] = Transition(from_map, to_map, reason)
+
+
+with open(filename, "r") as f:
+  last_to_map = ""
+  for line in f:
+    if not line.startswith("[TraceMaps: "): continue
+    words = line.split(" ")
+    event = words[1]
+    if event == "InitialMap":
+      assert words[2] == "map="
+      assert words[4] == "SFI="
+      new_map = AddMap(words[3], "SFI#%s" % words[5])
+      root_maps.append(new_map)
+      continue
+    if words[2] == "from=" and words[4] == "to=":
+      from_map = words[3]
+      to_map = words[5]
+      if from_map not in annotations:
+        print("// warning: unknown from_map %s" % from_map)
+        new_map = AddMap(from_map, "<unknown>")
+        root_maps.append(new_map)
+      if to_map != last_to_map:
+        AddMap(to_map, "<transition> (%s)" % event)
+      last_to_map = to_map
+      if event in ["Transition", "NoTransition"]:
+        assert words[6] == "name=", line
+        reason = "%s: %s" % (event, words[7])
+      elif event in ["Normalize", "ReplaceDescriptors", "SlowToFast"]:
+        assert words[6] == "reason=", line
+        reason = "%s: %s" % (event, words[7])
+        if words[8].strip() != "]":
+          reason = "%s_%s" % (reason, words[8])
+      else:
+        reason = event
+      AddTransition(from_map, to_map, reason)
+      continue
+
+
+def PlainPrint(m, indent, label):
+  print("%s%s (%s)" % (indent, m, label))
+  if m in transitions:
+    for t in transitions[m]:
+      PlainPrint(t, indent + "  ", transitions[m][t].reason)
+
+
+def CountTransitions(m):
+  if m not in transitions: return 0
+  return len(transitions[m])
+
+
+def DotPrint(m, label):
+  print("m%s [label=\"%s\"]" % (m[2:], label))
+  if m in transitions:
+    for t in transitions[m]:
+      # GraphViz doesn't like node labels looking like numbers, so use
+      # "m..." instead of "0x...".
+      print("m%s -> m%s" % (m[2:], t[2:]))
+      reason = transitions[m][t].reason
+      reason = reason.replace("\\", "BACKSLASH")
+      reason = reason.replace("\"", "\\\"")
+      DotPrint(t, reason)
+
+
+if action == "plain":
+  root_maps = sorted(root_maps, key=CountTransitions, reverse=True)
+  for m in root_maps:
+    PlainPrint(m, "", maps[m].origin)
+
+elif action == "dot":
+  print("digraph g {")
+  for m in root_maps:
+    DotPrint(m, maps[m].origin)
+  print("}")
+
+elif action == "count":
+  reasons = {}
+  for s in transitions:
+    for t in transitions[s]:
+      reason = transitions[s][t].reason
+      if reason not in reasons:
+        reasons[reason] = 1
+      else:
+        reasons[reason] += 1
+  reasons_list = []
+  for r in reasons:
+    reasons_list.append("%8d %s" % (reasons[r], r))
+  reasons_list.sort(reverse=True)
+  for r in reasons_list[:20]:
+    print r