[Interpreter] List top dispatch sources and destinations for a given Ignition bytecode.

tools/ignition/bytecode_dispatches_report.py

 #! /usr/bin/python
 #
 # Copyright 2016 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 argparse
 import heapq
 import json
@@ skipping 22 matching lines @@
   $ tools/ignition/bytecode_dispatches_report.py -t -n 15 data.json
 
   # Save heatmap to default filename v8.ignition_dispatches_counters.svg
   $ tools/ignition/bytecode_dispatches_report.py -p
 
   # Save heatmap to filename data.svg
   $ tools/ignition/bytecode_dispatches_report.py -p -o data.svg
 
   # Open the heatmap in an interactive viewer
   $ tools/ignition/bytecode_dispatches_report.py -p -i
+
+  # Display the top 5 sources and destinations of dispatches to/from LdaZero
+  $ tools/ignition/bytecode_dispatches_report.py -f LdaZero -n 5
 """
 
 __COUNTER_BITS = struct.calcsize("P") * 8  # Size in bits of a pointer
 __COUNTER_MAX = 2**__COUNTER_BITS - 1
 
 
 def warn_if_counter_may_have_saturated(dispatches_table):
   for source, counters_from_source in dispatches_table.items():
     for destination, counter in counters_from_source.items():
       if counter == __COUNTER_MAX:
@@ skipping 27 matching lines @@
   return top_bytecodes
 
 
 def print_top_bytecodes(dispatches_table):
   top_bytecodes = find_top_bytecodes(dispatches_table)
   print "Top bytecodes:"
   for bytecode, counter in top_bytecodes:
     print "{:>12d}\t{}".format(counter, bytecode)
 
 
+def find_top_dispatch_sources(dispatches_table, destination, top_count):
+  def source_counters_generator():
+    for source, table_row in dispatches_table.items():
+      if destination in table_row:
+        yield source, table_row[destination]
+
+  return heapq.nlargest(top_count, source_counters_generator(),
+                        key=lambda x: x[1])
+
+
+def print_top_dispatch_sources_and_destinations(dispatches_table, bytecode,
+                                                top_count):
+  top_sources = find_top_dispatch_sources(dispatches_table, bytecode, top_count)
+  top_destinations = heapq.nlargest(top_count,
+                                    dispatches_table[bytecode].items(),
+                                    key=lambda x: x[1])
+
+  print "Top sources of dispatches to {}:".format(bytecode)
+  for source_name, counter in top_sources:
+    print "{:>12d}\t{}".format(counter, source_name)
+
+  print "\nTop destinations of dispatches from {}:".format(bytecode)
+  for destination_name, counter in top_destinations:
+    print "{:>12d}\t{}".format(counter, destination_name)
+
+
 def build_counters_matrix(dispatches_table):
   labels = sorted(dispatches_table.keys())
 
   counters_matrix = numpy.empty([len(labels), len(labels)], dtype=int)
   for from_index, from_name in enumerate(labels):
     current_row = dispatches_table[from_name];
     for to_index, to_name in enumerate(labels):
       counters_matrix[from_index, to_index] = current_row.get(to_name, 0)
 
   # Reverse y axis for a nicer appearance
@@ skipping 60 matching lines @@
     "--interactive", "-i",
     action="store_true",
     help="open the heatmap in an interactive viewer, instead of writing to file"
   )
   command_line_parser.add_argument(
     "--top-bytecode-dispatch-pairs", "-t",
     action="store_true",
     help="print the top bytecode dispatch pairs"
   )
   command_line_parser.add_argument(
-    "--top-bytecode-dispatch-pairs-number", "-n",
+    "--top-entries-count", "-n",
     metavar="N",
     type=int,
     default=10,
-    help="print N top bytecode dispatch pairs when running with -t (default 10)"
+    help="print N top entries when running with -t or -f (default 10)"
+  )
+  command_line_parser.add_argument(
+    "--top-dispatches-for-bytecode", "-f",
+    metavar="<bytecode name>",
+    help="print top dispatch sources and destinations to the specified bytecode"
   )
   command_line_parser.add_argument(
     "--output-filename", "-o",
     metavar="<output filename>",
     default="v8.ignition_dispatches_table.svg",
     help=("file to save the plot file to. File type is deduced from the "
           "extension. PDF, SVG, PNG supported")
   )
   command_line_parser.add_argument(
     "input_filename",
@@ skipping 19 matching lines @@
     plot_dispatches_table(dispatches_table, figure, axis)
 
     if program_options.interactive:
       pyplot.show()
     else:
       figure.set_size_inches(program_options.plot_size,
                              program_options.plot_size)
       pyplot.savefig(program_options.output_filename)
   elif program_options.top_bytecode_dispatch_pairs:
     print_top_bytecode_dispatch_pairs(
-      dispatches_table, program_options.top_bytecode_dispatch_pairs_number)
+      dispatches_table, program_options.top_entries_count)
+  elif program_options.top_dispatches_for_bytecode:
+    print_top_dispatch_sources_and_destinations(
+      dispatches_table, program_options.top_dispatches_for_bytecode,
+      program_options.top_entries_count)
   else:
     print_top_bytecodes(dispatches_table)
 
 
 if __name__ == "__main__":
   main()