cpython/Python/makeopcodetargets.py
Antoine Pitrou b52ec78baf Issue #4753: By enabling a configure option named '--with-computed-gotos'
on compilers that support it (notably: gcc, SunPro, icc), the bytecode
evaluation loop is compiled with a new dispatch mechanism which gives
speedups of up to 20%, depending on the system, on various benchmarks.
2009-01-25 16:34:23 +00:00

43 lines
1.2 KiB
Python

#! /usr/bin/env python
"""Generate C code for the jump table of the threaded code interpreter
(for compilers supporting computed gotos or "labels-as-values", such as gcc).
"""
import imp
import os
def find_module(modname):
"""Finds and returns a module in the local dist/checkout.
"""
modpath = os.path.join(
os.path.dirname(os.path.dirname(__file__)), "Lib")
return imp.load_module(modname, *imp.find_module(modname, [modpath]))
def write_contents(f):
"""Write C code contents to the target file object.
"""
opcode = find_module("opcode")
targets = ['_unknown_opcode'] * 256
for opname, op in opcode.opmap.items():
if opname == "STOP_CODE":
# XXX opcode not implemented
continue
targets[op] = "TARGET_%s" % opname
f.write("static void *opcode_targets[256] = {\n")
f.write(",\n".join("\t&&%s" % s for s in targets))
f.write("\n};\n")
if __name__ == "__main__":
import sys
assert len(sys.argv) < 3, "Too many arguments"
if len(sys.argv) == 2:
target = sys.argv[1]
else:
target = "Python/opcode_targets.h"
f = open(target, "w")
try:
write_contents(f)
finally:
f.close()