make_ffi.py

import re
import cffi
import subprocess

import logging
l = logging.getLogger('cffier')
l.setLevel(logging.DEBUG)

def find_good_bsearch(known_good, questionable):
    ffi = cffi.FFI()
    l.debug("bsearch - trying %d good and %d questionable", len(known_good), len(questionable))

    try:
        ffi.cdef('\n'.join(known_good + questionable))
    except (cffi.CDefError, AssertionError):
        return find_good_bsearch(known_good, questionable[:len(questionable)/2])

    return questionable

def find_good_scan(known_good, questionable):
    ffi = cffi.FFI()
    l.debug("scan - trying %d good and %d questionable", len(known_good), len(questionable))

    #print "GOOD:"
    #print '  ...'
    #print '  ' + '\n  '.join(known_good[-5:])
    #print "UNKNOWN:"
    #print '  ' + '\n  '.join(questionable[:5])
    #print '  ...'
    #print '  ' + '\n  '.join(questionable[-5:])

    try:
        ffi.cdef('\n'.join(known_good + questionable))
        return questionable
    except AssertionError:
        return [ ]
    except cffi.CDefError as e:
        if str(e).count(':') >= 2:
            fail = int(str(e).split('\n')[1].split(':')[1])
        elif 'unrecognized construct' in str(e):
            fail = int(str(e).split()[1][:-1])
        elif 'end of input' in str(e):
            return find_good_scan(known_good, questionable[:-1])
        else:
            raise Exception("Unknown error")
    except cffi.FFIError as e:
        if str(e).count(':') >= 2:
            fail = int(str(e).split('\n')[0].split(':')[1])
        else:
            raise Exception("Unknown error")

    return find_good_scan(known_good, questionable[:fail-2-len(known_good)])

def doit(vex_path):
    #vex_pp,_ = subprocess.Popen(['cpp', 'vex/pub/libvex.h'], stdout=subprocess.PIPE, stderr=subprocess.STDOUT).communicate()
    header,_ = subprocess.Popen(['cpp', '-I'+vex_path, 'pyvex_c/pyvex_static.h'], stdout=subprocess.PIPE, stderr=subprocess.STDOUT).communicate()
    #header = vex_pp + pyvex_pp

    linesep = '\r\n' if '\r\n' in header else '\n'
    ffi_text = linesep.join(line for line in header.split(linesep) if '#' not in line and line.strip() != '' and 'jmp_buf' not in line)
    ffi_text = re.sub('\{\s*\} NoOp;', '{ int DONOTUSE; } NoOp;', ffi_text)
    ffi_text = re.sub('__attribute__\s*\(.*\)', '', ffi_text)
    ffi_text = ffi_text.replace('__const', 'const')
    ffi_lines = ffi_text.split(linesep)

    good = find_good_scan([], ffi_lines)
    remaining = ffi_lines[len(good)+1:]

    while len(remaining) > 1:
        l.debug("%d uncertain lines remaining", len(remaining))
        new_good = find_good_scan(good, remaining[1:])
        good += new_good
        remaining = remaining[len(new_good)+1:]

    good += [ 'extern VexControl vex_control;' ]

    open('pyvex/vex_ffi.py', 'w').write('ffi_str = """' + '\n'.join(good) + '"""')

if __name__ == '__main__':
    import sys
    doit(sys.argv[1])