Python/makeopcodetargets.py

   1 #! /usr/bin/env python
   2 """Generate C code for the jump table of the threaded code interpreter
   3 (for compilers supporting computed gotos or "labels-as-values", such as gcc).
   4 """
   5
   6 # This code should stay compatible with Python 2.3, at least while
   7 # some of the buildbots have Python 2.3 as their system Python.
   8
   9 import imp
  10 import os
  11
  12
  13 def find_module(modname):
  14     """Finds and returns a module in the local dist/checkout.
  15     """
  16     modpath = os.path.join(
  17         os.path.dirname(os.path.dirname(__file__)), "Lib")
  18     return imp.load_module(modname, *imp.find_module(modname, [modpath]))
  19
  20 def write_contents(f):
  21     """Write C code contents to the target file object.
  22     """
  23     opcode = find_module("opcode")
  24     targets = ['_unknown_opcode'] * 256
  25     for opname, op in opcode.opmap.items():
  26         if opname == "STOP_CODE":
  27             # XXX opcode not implemented
  28             continue
  29         targets[op] = "TARGET_%s" % opname
  30     f.write("static void *opcode_targets[256] = {\n")
  31     f.write(",\n".join(["    &&%s" % s for s in targets]))
  32     f.write("\n};\n")
  33
  34
  35 if __name__ == "__main__":
  36     import sys
  37     assert len(sys.argv) < 3, "Too many arguments"
  38     if len(sys.argv) == 2:
  39         target = sys.argv[1]
  40     else:
  41         target = "Python/opcode_targets.h"
  42     f = open(target, "w")
  43     try:
  44         write_contents(f)
  45     finally:
  46         f.close()