path: root/configure.py

#!/usr/bin/env python

"""
Configuration program for botan (http://botan.randombit.net/)
  (C) 2009,2010,2011,2012 Jack Lloyd
  Distributed under the terms of the Botan license

Tested with CPython 2.6, 2.7, 3.1 and PyPy 1.5

Python 2.5 works if you change the exception catching syntax:
   perl -pi -e 's/except (.*) as (.*):/except $1, $2:/g' configure.py

Jython - Target detection does not work (use --os and --cpu)

CPython 2.4 and earlier are not supported

Has not been tested with IronPython
"""

import sys
import os
import os.path
import platform
import re
import shlex
import shutil
import string
import subprocess
import logging
import getpass
import time
import errno
import optparse

# Avoid useless botan_version.pyc (Python 2.6 or higher)
if 'dont_write_bytecode' in sys.__dict__:
    sys.dont_write_bytecode = True

import botan_version

def flatten(l):
    return sum(l, [])

def get_vc_revision():
    try:
        mtn = subprocess.Popen(['mtn', 'automate', 'heads'],
                               stdout=subprocess.PIPE,
                               stderr=subprocess.PIPE)

        (stdout, stderr) = mtn.communicate()

        if(stderr != ''):
            logging.debug('Error getting rev from monotone - %s' % (stderr))
            return 'unknown'

        logging.debug('Monotone reported revision ' + stdout.strip())

        return 'mtn:' + stdout.strip()
    except OSError as e:
        logging.debug('Error getting rev from monotone - %s' % (e[1]))
        return 'unknown'

class BuildConfigurationInformation(object):

    """
    Version information
    """
    version_major = botan_version.release_major
    version_minor = botan_version.release_minor
    version_patch = botan_version.release_patch
    version_so_rev = botan_version.release_so_abi_rev

    version_datestamp = botan_version.release_datestamp

    version_vc_rev = botan_version.release_vc_rev
    version_string = '%d.%d.%d' % (version_major, version_minor, version_patch)

    """
    Constructor
    """
    def __init__(self, options, modules):

        if self.version_vc_rev is None:
            self.version_vc_rev = get_vc_revision()

        self.build_dir = os.path.join(options.with_build_dir, 'build')

        self.checkobj_dir = os.path.join(self.build_dir, 'checks')
        self.libobj_dir = os.path.join(self.build_dir, 'lib')

        self.python_dir = os.path.join(options.src_dir, 'wrap', 'python')

        self.boost_python = options.boost_python

        self.doc_output_dir = os.path.join(self.build_dir, 'docs')

        self.pyobject_dir = os.path.join(self.build_dir, 'python')

        self.include_dir = os.path.join(self.build_dir, 'include')
        self.botan_include_dir = os.path.join(self.include_dir, 'botan')
        self.internal_include_dir = os.path.join(self.botan_include_dir, 'internal')

        self.sources = sorted(flatten([mod.sources() for mod in modules]))
        self.internal_headers = sorted(flatten([m.internal_headers() for m in modules]))

        if options.via_amalgamation:
            self.build_sources = ['botan_all.cpp']
            self.build_internal_headers = []
        else:
            self.build_sources = self.sources
            self.build_internal_headers = self.internal_headers

        self.public_headers = sorted(flatten([m.public_headers() for m in modules]))

        checks_dir = os.path.join(options.base_dir, 'checks')

        self.check_sources = sorted(
            [os.path.join(checks_dir, file) for file in os.listdir(checks_dir)
             if file.endswith('.cpp')])

        self.python_sources = sorted(
            [os.path.join(self.python_dir, file)
             for file in os.listdir(self.python_dir)
             if file.endswith('.cpp')])

        self.manual_dir = os.path.join(self. doc_output_dir, 'manual')

        def build_doc_commands():
            yield '$(COPY) readme.txt %s' % (self.doc_output_dir)

            if options.with_sphinx:
                yield 'sphinx-build $(SPHINX_OPTS) -b html doc %s' % (
                    self.manual_dir)
            else:
                yield '$(COPY) doc/*.txt %s' % (self.manual_dir)

            if options.with_doxygen:
                yield 'doxygen %s/botan.doxy' % (self.build_dir)

        self.build_doc_commands = '\n'.join(['\t' + s for s in build_doc_commands()])

        def build_dirs():
            yield self.checkobj_dir
            yield self.libobj_dir
            yield self.botan_include_dir
            yield self.internal_include_dir
            yield os.path.join(self.doc_output_dir, 'manual')
            if options.with_doxygen:
                yield os.path.join(self.doc_output_dir, 'doxygen')

            if self.boost_python:
                yield self.pyobject_dir

        self.build_dirs = list(build_dirs())

    def pkg_config_file(self):
        return 'botan-%d.%d.pc' % (self.version_major,
                                   self.version_minor)

    def config_shell_script(self):
        return 'botan-config-%d.%d' % (self.version_major,
                                       self.version_minor)

    def username(self):
        return getpass.getuser()

    def hostname(self):
        return platform.node()

    def timestamp(self):
        return time.ctime()

"""
Handle command line options
"""
def process_command_line(args):

    parser = optparse.OptionParser(
        formatter = optparse.IndentedHelpFormatter(max_help_position = 50),
        version = BuildConfigurationInformation.version_string)

    parser.add_option('--verbose', action='store_true', default=False,
                      help='Show debug messages')
    parser.add_option('--quiet', action='store_true', default=False,
                      help='Show only warnings and errors')

    target_group = optparse.OptionGroup(parser, 'Target options')

    target_group.add_option('--cpu',
                            help='set the target processor type/model')

    target_group.add_option('--os',
                            help='set the target operating system')

    target_group.add_option('--cc', dest='compiler',
                            help='set the desired build compiler')

    target_group.add_option('--cc-bin', dest='compiler_binary',
                            metavar='BINARY',
                            help='set the name of the compiler binary')

    target_group.add_option('--with-endian', metavar='ORDER', default=None,
                            help='override guess of CPU byte order')

    target_group.add_option('--with-unaligned-mem',
                            dest='unaligned_mem', action='store_true',
                            default=None,
                            help='enable unaligned memory accesses')

    target_group.add_option('--without-unaligned-mem',
                            dest='unaligned_mem', action='store_false',
                            help=optparse.SUPPRESS_HELP)

    for isa_extn_name in ['SSE2', 'SSSE3', 'AltiVec', 'AES-NI', 'movbe']:
        isa_extn = isa_extn_name.lower()

        target_group.add_option('--enable-%s' % (isa_extn),
                                help='enable use of %s' % (isa_extn_name),
                                action='append_const',
                                const=isa_extn,
                                dest='enable_isa_extns')

        target_group.add_option('--disable-%s' % (isa_extn),
                                help=optparse.SUPPRESS_HELP,
                                action='append_const',
                                const=isa_extn,
                                dest='disable_isa_extns')

    build_group = optparse.OptionGroup(parser, 'Build options')

    build_group.add_option('--enable-shared', dest='build_shared_lib',
                           action='store_true', default=True,
                            help=optparse.SUPPRESS_HELP)
    build_group.add_option('--disable-shared', dest='build_shared_lib',
                           action='store_false',
                           help='disable building a shared library')

    build_group.add_option('--enable-asm', dest='asm_ok',
                           action='store_true', default=True,
                           help=optparse.SUPPRESS_HELP)
    build_group.add_option('--disable-asm', dest='asm_ok',
                           action='store_false',
                           help='disallow use of assembler')

    build_group.add_option('--enable-debug', dest='debug_build',
                           action='store_true', default=False,
                           help='enable debug build')
    build_group.add_option('--disable-debug', dest='debug_build',
                           action='store_false', help=optparse.SUPPRESS_HELP)

    build_group.add_option('--no-optimizations', dest='no_optimizations',
                           action='store_true', default=False,
                           help=optparse.SUPPRESS_HELP)

    build_group.add_option('--gen-amalgamation', dest='gen_amalgamation',
                           default=False, action='store_true',
                           help='generate amalgamation files')

    build_group.add_option('--via-amalgamation', dest='via_amalgamation',
                           default=False, action='store_true',
                           help='build via amalgamation')

    build_group.add_option('--with-build-dir',
                           metavar='DIR', default='',
                           help='setup the build in DIR')

    build_group.add_option('--makefile-style', metavar='STYLE', default=None,
                           help='choose a makefile style (unix or nmake)')

    build_group.add_option('--with-local-config',
                           dest='local_config', metavar='FILE',
                           help='include the contents of FILE into build.h')

    build_group.add_option('--distribution-info', metavar='STRING',
                           help='set distribution specific versioning',
                           default='unspecified')

    build_group.add_option('--with-sphinx', action='store_true',
                           default=None,
                           help='Use Sphinx to generate HTML manual')

    build_group.add_option('--without-sphinx', action='store_false',
                           dest='with_sphinx', help=optparse.SUPPRESS_HELP)

    build_group.add_option('--with-visibility', action='store_true',
                           default=None, help=optparse.SUPPRESS_HELP)

    build_group.add_option('--without-visibility', action='store_false',
                           dest='with_visibility', help=optparse.SUPPRESS_HELP)

    build_group.add_option('--with-doxygen', action='store_true',
                           default=False,
                           help='Use Doxygen to generate HTML API docs')

    build_group.add_option('--without-doxygen', action='store_false',
                           dest='with_doxygen', help=optparse.SUPPRESS_HELP)

    build_group.add_option('--maintainer-mode', dest='maintainer_mode',
                           action='store_true', default=False,
                           help=optparse.SUPPRESS_HELP)

    build_group.add_option('--dirty-tree', dest='clean_build_tree',
                           action='store_false', default=True,
                           help=optparse.SUPPRESS_HELP)

    build_group.add_option('--link-method',
                           default=None,
                           help=optparse.SUPPRESS_HELP)

    wrapper_group = optparse.OptionGroup(parser, 'Wrapper options')

    wrapper_group.add_option('--with-boost-python', dest='boost_python',
                             default=False, action='store_true',
                             help='enable Boost.Python wrapper')

    wrapper_group.add_option('--without-boost-python',
                             dest='boost_python',
                             action='store_false',
                             help=optparse.SUPPRESS_HELP)

    wrapper_group.add_option('--with-python-version', dest='python_version',
                             metavar='N.M',
                             default='.'.join(map(str, sys.version_info[0:2])),
                             help='specify Python to build against (eg %default)')

    mods_group = optparse.OptionGroup(parser, 'Module selection')

    mods_group.add_option('--enable-modules', dest='enabled_modules',
                          metavar='MODS', action='append',
                          help='enable specific modules')
    mods_group.add_option('--disable-modules', dest='disabled_modules',
                          metavar='MODS', action='append',
                          help='disable specific modules')
    mods_group.add_option('--no-autoload', action='store_true', default=False,
                          help='disable automatic loading')

    for lib in ['OpenSSL', 'GNU MP', 'Bzip2', 'Zlib']:

        mod = lib.lower().replace(' ', '')

        mods_group.add_option('--with-%s' % (mod),
                              help='add support for using %s' % (lib),
                              action='append_const',
                              const=mod,
                              dest='enabled_modules')

        mods_group.add_option('--without-%s' % (mod),
                              help=optparse.SUPPRESS_HELP,
                              action='append_const',
                              const=mod,
                              dest='disabled_modules')

    install_group = optparse.OptionGroup(parser, 'Installation options')

    install_group.add_option('--prefix', metavar='DIR',
                             help='set the base install directory')
    install_group.add_option('--docdir', metavar='DIR',
                             help='set the documentation install directory')
    install_group.add_option('--libdir', metavar='DIR',
                             help='set the library install directory')
    install_group.add_option('--includedir', metavar='DIR',
                             help='set the include file install directory')

    parser.add_option_group(target_group)
    parser.add_option_group(build_group)
    parser.add_option_group(mods_group)
    parser.add_option_group(wrapper_group)
    parser.add_option_group(install_group)

    # These exist only for autoconf compatability (requested by zw for mtn)
    compat_with_autoconf_options = [
        'bindir',
        'datadir',
        'datarootdir',
        'dvidir',
        'exec-prefix',
        'htmldir',
        'infodir',
        'libexecdir',
        'localedir',
        'localstatedir',
        'mandir',
        'oldincludedir',
        'pdfdir',
        'psdir',
        'sbindir',
        'sharedstatedir',
        'sysconfdir'
        ]

    for opt in compat_with_autoconf_options:
        parser.add_option('--' + opt, help=optparse.SUPPRESS_HELP)

    (options, args) = parser.parse_args(args)

    if args != []:
        raise Exception('Unhandled option(s): ' + ' '.join(args))
    if options.with_endian != None and \
       options.with_endian not in ['little', 'big']:
        raise Exception('Bad value to --with-endian "%s"' % (
            options.with_endian))

    def parse_multiple_enable(modules):
        if modules is None:
            return []
        return sorted(set(flatten([s.split(',') for s in modules])))

    options.enabled_modules = parse_multiple_enable(options.enabled_modules)
    options.disabled_modules = parse_multiple_enable(options.disabled_modules)

    options.enable_isa_extns = parse_multiple_enable(options.enable_isa_extns)
    options.disable_isa_extns = parse_multiple_enable(options.disable_isa_extns)

    def enabled_or_disabled_isa(isa):
        if isa in options.enable_isa_extns:
            return True
        if isa in options.disable_isa_extns:
            return True
        return False

    isa_deps = {
        'ssse3': 'sse2',
        'aes-ni': 'sse2'
        }

    if 'sse2' in options.disable_isa_extns:
        for isa in [k for (k,v) in isa_deps.items() if v == 'sse2']:
            # If explicitly enabled, allow it even if a dependency
            # violation; trust the user to know what they want
            if not enabled_or_disabled_isa(isa):
                options.disable_isa_extns.append(isa)

    for isa in options.enable_isa_extns:
        if isa in isa_deps:
            for dep in isa_deps.get(isa, '').split(','):
                if not enabled_or_disabled_isa(dep):
                    options.enable_isa_extns.append(dep)

    return options

"""
Generic lexer function for info.txt and src/build-data files
"""
def lex_me_harder(infofile, to_obj, allowed_groups, name_val_pairs):

    # Format as a nameable Python variable
    def py_var(group):
        return group.replace(':', '_')

    class LexerError(Exception):
        def __init__(self, msg, line):
            self.msg = msg
            self.line = line

        def __str__(self):
            return '%s at %s:%d' % (self.msg, infofile, self.line)

    (dirname, basename) = os.path.split(infofile)

    to_obj.lives_in = dirname
    if basename == 'info.txt':
        (obj_dir,to_obj.basename) = os.path.split(dirname)
        if os.access(os.path.join(obj_dir, 'info.txt'), os.R_OK):
            to_obj.parent_module = os.path.basename(obj_dir)
        else:
            to_obj.parent_module = None
    else:
        to_obj.basename = basename.replace('.txt', '')

    lexer = shlex.shlex(open(infofile), infofile, posix=True)
    lexer.wordchars += '|:.<>/,-!+' # handle various funky chars in info.txt

    for group in allowed_groups:
        to_obj.__dict__[py_var(group)] = []
    for (key,val) in name_val_pairs.items():
        to_obj.__dict__[key] = val

    def lexed_tokens(): # Convert to an interator
        token = lexer.get_token()
        while token != None:
            yield token
            token = lexer.get_token()

    for token in lexed_tokens():
        match = re.match('<(.*)>', token)

        # Check for a grouping
        if match is not None:
            group = match.group(1)

            if group not in allowed_groups:
                raise LexerError('Unknown group "%s"' % (group),
                                 lexer.lineno)

            end_marker = '</' + group + '>'

            token = lexer.get_token()
            while token != end_marker:
                to_obj.__dict__[py_var(group)].append(token)
                token = lexer.get_token()
                if token is None:
                    raise LexerError('Group "%s" not terminated' % (group),
                                     lexer.lineno)

        elif token in name_val_pairs.keys():
            next_val = lexer.get_token()

            if type(to_obj.__dict__[token]) is list:
                to_obj.__dict__[token].append(next_val)
            else:
                to_obj.__dict__[token] = next_val

        else: # No match -> error
            raise LexerError('Bad token "%s"' % (token), lexer.lineno)

"""
Convert a lex'ed map (from build-data files) from a list to a dict
"""
def force_to_dict(l):
    return dict(zip(l[::3],l[2::3]))

"""
Represents the information about a particular module
"""
class ModuleInfo(object):
    def __init__(self, infofile):

        lex_me_harder(infofile, self,
                      ['source', 'header:internal', 'header:public',
                       'requires', 'os', 'arch', 'cc', 'libs',
                       'comment'],
                      {
                        'load_on': 'auto',
                        'define': [],
                        'need_isa': None,
                        'mp_bits': 0 })

        if self.source == [] and \
            self.header_internal == [] and \
            self.header_public == []:

            for (dirpath, dirnames, filenames) in os.walk(self.lives_in):
                if dirpath == self.lives_in:
                    for filename in filenames:
                        if filename.startswith('.'):
                            continue

                        if filename.endswith('.cpp') or \
                           filename.endswith('.S'):
                            self.source.append(filename)
                        elif filename.endswith('.h'):
                            self.header_public.append(filename)

        # Coerce to more useful types
        def convert_lib_list(l):
            result = {}
            for (targetlist, vallist) in zip(l[::3], l[2::3]):
                vals = vallist.split(',')
                for target in targetlist.split(','):
                    result[target] = result.setdefault(target, []) + vals
            return result

        self.libs = convert_lib_list(self.libs)

        def add_dir_name(filename):
            if filename.count(':') == 0:
                return os.path.join(self.lives_in, filename)

            # modules can request to add files of the form
            # MODULE_NAME:FILE_NAME to add a file from another module
            # For these, assume other module is always in a
            # neighboring directory; this is true for all current uses
            return os.path.join(os.path.split(self.lives_in)[0],
                                *filename.split(':'))

        self.source = [add_dir_name(s) for s in self.source]
        self.header_internal = [add_dir_name(s) for s in self.header_internal]
        self.header_public = [add_dir_name(s) for s in self.header_public]

        self.mp_bits = int(self.mp_bits)

        if self.comment != []:
            self.comment = ' '.join(self.comment)
        else:
            self.comment = None

    def sources(self):
        return self.source

    def public_headers(self):
        return self.header_public

    def internal_headers(self):
        return self.header_internal

    def defines(self):
        return ['HAS_' + d for d in self.define]

    def compatible_cpu(self, archinfo, options):

        arch_name = archinfo.basename
        cpu_name = options.cpu

        if self.arch != []:
            if arch_name not in self.arch and cpu_name not in self.arch:
                return False

        if self.need_isa != None:
            if self.need_isa in options.disable_isa_extns:
                return False # explicitly disabled

            if self.need_isa in options.enable_isa_extns:
                return True # explicitly enabled

            # Default to whatever the CPU is supposed to support
            return self.need_isa in archinfo.isa_extensions_in(cpu_name)

        return True

    def compatible_os(self, os):
        return self.os == [] or os in self.os

    def compatible_compiler(self, cc):
        return self.cc == [] or cc in self.cc

    def dependencies(self):
        # utils is an implicit dep (contains types, etc)
        deps = self.requires + ['utils']
        if self.parent_module != None:
            deps.append(self.parent_module)
        return deps

    """
    Ensure that all dependencies of this module actually exist, warning
    about any that do not
    """
    def dependencies_exist(self, modules):
        all_deps = [s.split('|') for s in self.dependencies()]

        for missing in [s for s in flatten(all_deps) if s not in modules]:
            logging.warn("Module '%s', dep of '%s', does not exist" % (
                missing, self.basename))

    def __cmp__(self, other):
        if self.basename < other.basename:
            return -1
        if self.basename == other.basename:
            return 0
        return 1

class ArchInfo(object):
    def __init__(self, infofile):
        lex_me_harder(infofile, self,
                      ['aliases', 'submodels', 'submodel_aliases', 'isa_extn'],
                      { 'endian': None,
                        'family': None,
                        'unaligned': 'no'
                        })

        def convert_isa_list(input):
            isa_info = {}
            for line in self.isa_extn:
                (isa,cpus) = line.split(':')
                for cpu in cpus.split(','):
                    isa_info.setdefault(cpu, []).append(isa)
            return isa_info

        self.isa_extn = convert_isa_list(self.isa_extn)

        self.submodel_aliases = force_to_dict(self.submodel_aliases)

        self.unaligned_ok = (1 if self.unaligned == 'ok' else 0)

    """
    Return ISA extensions specific to this CPU
    """
    def isa_extensions_in(self, cpu_type):
        return sorted(self.isa_extn.get(cpu_type, []) +
                      self.isa_extn.get('all', []))

    """
    Return a list of all submodels for this arch, ordered longest
    to shortest
    """
    def all_submodels(self):
        return sorted([(k,k) for k in self.submodels] +
                      [k for k in self.submodel_aliases.items()],
                      key = lambda k: len(k[0]), reverse = True)

    """
    Return CPU-specific defines for build.h
    """
    def defines(self, options):
        def form_macro(cpu_name):
            return cpu_name.upper().replace('.', '').replace('-', '_')

        macros = ['TARGET_ARCH_IS_%s' %
                  (form_macro(self.basename.upper()))]

        if self.basename != options.cpu:
            macros.append('TARGET_CPU_IS_%s' % (form_macro(options.cpu)))

        enabled_isas = set(self.isa_extensions_in(options.cpu) +
                           options.enable_isa_extns)
        disabled_isas = set(options.disable_isa_extns)

        isa_extensions = sorted(enabled_isas - disabled_isas)

        for isa in isa_extensions:
            macros.append('TARGET_CPU_HAS_%s' % (form_macro(isa)))

        endian = options.with_endian or self.endian

        if endian != None:
            macros.append('TARGET_CPU_IS_%s_ENDIAN' % (endian.upper()))
            logging.info('Assuming CPU is %s endian' % (endian))

        unaligned_ok = options.unaligned_mem
        if unaligned_ok is None:
            unaligned_ok = self.unaligned_ok
            if unaligned_ok:
                logging.info('Assuming unaligned memory access works')

        if self.family is not None:
            macros.append('TARGET_CPU_IS_%s_FAMILY' % (self.family.upper()))

        macros.append('TARGET_UNALIGNED_MEMORY_ACCESS_OK %d' % (unaligned_ok))

        return macros

class CompilerInfo(object):
    def __init__(self, infofile):
        lex_me_harder(infofile, self,
                      ['so_link_flags', 'mach_opt', 'mach_abi_linking'],
                      { 'binary_name': None,
                        'macro_name': None,
                        'compile_option': '-c ',
                        'output_to_option': '-o ',
                        'add_include_dir_option': '-I',
                        'add_lib_dir_option': '-L',
                        'add_lib_option': '-l',
                        'lib_opt_flags': '',
                        'check_opt_flags': '',
                        'debug_flags': '',
                        'no_debug_flags': '',
                        'shared_flags': '',
                        'lang_flags': '',
                        'warning_flags': '',
                        'maintainer_warning_flags': '',
                        'visibility_build_flags': '',
                        'visibility_attribute': '',
                        'ar_command': None,
                        'makefile_style': ''
                        })

        self.so_link_flags = force_to_dict(self.so_link_flags)
        self.mach_abi_linking = force_to_dict(self.mach_abi_linking)

        self.mach_opt_flags = {}

        while self.mach_opt != []:
            proc = self.mach_opt.pop(0)
            if self.mach_opt.pop(0) != '->':
                raise Exception('Parsing err in %s mach_opt' % (self.basename))

            flags = self.mach_opt.pop(0)
            regex = ''

            if len(self.mach_opt) > 0 and \
               (len(self.mach_opt) == 1 or self.mach_opt[1] != '->'):
                regex = self.mach_opt.pop(0)

            self.mach_opt_flags[proc] = (flags,regex)

        del self.mach_opt

    """
    Return the shared library build flags, if any
    """
    def gen_shared_flags(self, options):
        def flag_builder():
            if options.build_shared_lib:
                yield self.shared_flags
                if options.with_visibility:
                    yield self.visibility_build_flags

        return ' '.join(list(flag_builder()))

    def gen_visibility_attribute(self, options):
        if options.build_shared_lib and options.with_visibility:
            return self.visibility_attribute
        return ''

    """
    Return the machine specific ABI flags
    """
    def mach_abi_link_flags(self, osname, arch, submodel, debug_p):

        def all():
            if debug_p:
                return 'all-debug'
            return 'all'

        abi_link = set()
        for what in [all(), osname, arch, submodel]:
            if self.mach_abi_linking.get(what) != None:
                abi_link.add(self.mach_abi_linking.get(what))

        if len(abi_link) == 0:
            return ''
        return ' ' + ' '.join(abi_link)

    """
    Return the flags for MACH_OPT
    """
    def mach_opts(self, arch, submodel):

        def submodel_fixup(tup):
            return tup[0].replace('SUBMODEL', submodel.replace(tup[1], ''))

        if submodel == arch:
            return ''

        if submodel in self.mach_opt_flags:
            return submodel_fixup(self.mach_opt_flags[submodel])
        if arch in self.mach_opt_flags:
            return submodel_fixup(self.mach_opt_flags[arch])

        return ''

    """
    Return the flags for LIB_OPT
    """
    def library_opt_flags(self, options):
        def gen_flags():
            if options.debug_build:
                yield self.debug_flags

            if not options.no_optimizations:
                yield self.lib_opt_flags

                if not options.debug_build:
                    yield self.no_debug_flags

        return (' '.join(gen_flags())).strip()

    """
    Return the command needed to link a shared object
    """
    def so_link_command_for(self, osname):
        if osname in self.so_link_flags:
            return self.so_link_flags[osname]
        if 'default' in self.so_link_flags:
            return self.so_link_flags['default']
        return ''

    """
    Return defines for build.h
    """
    def defines(self):
        return ['BUILD_COMPILER_IS_' + self.macro_name]

class OsInfo(object):
    def __init__(self, infofile):
        lex_me_harder(infofile, self,
                      ['aliases', 'target_features'],
                      { 'os_type': None,
                        'obj_suffix': 'o',
                        'so_suffix': 'so',
                        'static_suffix': 'a',
                        'ar_command': 'ar crs',
                        'ar_needs_ranlib': False,
                        'install_root': '/usr/local',
                        'header_dir': 'include',
                        'lib_dir': 'lib',
                        'doc_dir': 'share/doc',
                        'build_shared': 'yes',
                        'install_cmd_data': 'install -m 644',
                        'install_cmd_exec': 'install -m 755'
                        })

        self.ar_needs_ranlib = bool(self.ar_needs_ranlib)

        self.build_shared = (True if self.build_shared == 'yes' else False)

    def ranlib_command(self):
        return ('ranlib' if self.ar_needs_ranlib else 'true')

    def defines(self):
        return ['TARGET_OS_IS_%s' % (self.basename.upper())] + \
               ['TARGET_OS_HAS_' + feat.upper()
                for feat in sorted(self.target_features)]

def fixup_proc_name(proc):
    proc = proc.lower().replace(' ', '')
    for junk in ['(tm)', '(r)']:
        proc = proc.replace(junk, '')
    return proc

def canon_processor(archinfo, proc):
    proc = fixup_proc_name(proc)

    # First, try to search for an exact match
    for ainfo in archinfo.values():
        if ainfo.basename == proc or proc in ainfo.aliases:
            return (ainfo.basename, ainfo.basename)

        for (match,submodel) in ainfo.all_submodels():
            if proc == submodel or proc == match:
                return (ainfo.basename, submodel)

    logging.debug('Could not find an exact match for CPU "%s"' % (proc))

    # Now, try searching via regex match
    for ainfo in archinfo.values():
        for (match,submodel) in ainfo.all_submodels():
            if re.search(match, proc) != None:
                logging.debug('Possible match "%s" with "%s" (%s)' % (
                    proc, match, submodel))
                return (ainfo.basename, submodel)

    logging.debug('Known CPU names: ' + ' '.join(
        sorted(flatten([[ainfo.basename] + \
                        ainfo.aliases + \
                        [x for (x,_) in ainfo.all_submodels()]
                        for ainfo in archinfo.values()]))))

    raise Exception('Unknown or unidentifiable processor "%s"' % (proc))

def guess_processor(archinfo):
    base_proc = platform.machine()

    if base_proc == '':
        raise Exception('Could not determine target CPU; set with --cpu')

    full_proc = fixup_proc_name(platform.processor()) or base_proc

    for ainfo in archinfo.values():
        if ainfo.basename == base_proc or base_proc in ainfo.aliases:
            for (match,submodel) in ainfo.all_submodels():
                if re.search(match, full_proc) != None:
                    return (ainfo.basename, submodel)

            return canon_processor(archinfo, ainfo.basename)

    # No matches, so just use the base proc type
    return canon_processor(archinfo, base_proc)

"""
Read a whole file into memory as a string
"""
def slurp_file(filename):
    if filename is None:
        return ''
    return ''.join(open(filename).readlines())

"""
Perform template substitution
"""
def process_template(template_file, variables):
    class PercentSignTemplate(string.Template):
        delimiter = '%'

    try:
        template = PercentSignTemplate(slurp_file(template_file))
        return template.substitute(variables)
    except KeyError as e:
        raise Exception('Unbound var %s in template %s' % (e, template_file))

"""
Create the template variables needed to process the makefile, build.h, etc
"""
def create_template_vars(build_config, options, modules, cc, arch, osinfo):
    def make_cpp_macros(macros):
        return '\n'.join(['#define BOTAN_' + macro for macro in macros])

    """
    Figure out what external libraries are needed based on selected modules
    """
    def link_to():
        libs = set()
        for module in modules:
            for (osname,link_to) in module.libs.items():
                if osname == 'all' or osname == osinfo.basename:
                    libs |= set(link_to)
                else:
                    match = re.match('^all!(.*)', osname)
                    if match is not None:
                        exceptions = match.group(1).split(',')
                        if osinfo.basename not in exceptions:
                            libs |= set(link_to)
        return sorted(libs)

    def objectfile_list(sources, obj_dir):
        for src in sources:
            (dir,file) = os.path.split(os.path.normpath(src))

            if dir.startswith('src'):
                parts = dir.split(os.sep)[1:]

                # Handle src/X/X.cpp -> X.o
                if file == parts[-1] + '.cpp':
                    name = '_'.join(dir.split(os.sep)[1:]) + '.cpp'
                else:
                    name = '_'.join(dir.split(os.sep)[1:]) + '_' + file

                # Special case hack cause I'm lazy
                name = name.replace('tls_tls_', 'tls_')
            else:
                name = file

            for src_suffix in ['.cpp', '.S']:
                name = name.replace(src_suffix, '.' + osinfo.obj_suffix)

            yield os.path.join(obj_dir, name)


    def choose_mp_bits():
        mp_bits = [mod.mp_bits for mod in modules if mod.mp_bits != 0]

        if mp_bits == []:
            return 32 # default

        # Check that settings are consistent across modules
        for mp_bit in mp_bits[1:]:
            if mp_bit != mp_bits[0]:
                raise Exception('Incompatible mp_bits settings found')

        return mp_bits[0]

    """
    Form snippets of makefile for building each source file
    """
    def build_commands(sources, obj_dir, flags):
        for (obj_file,src) in zip(objectfile_list(sources, obj_dir), sources):
            yield '%s: %s\n\t$(CXX) %s%s $(%s_FLAGS) %s$? %s$@\n' % (
                obj_file, src,
                cc.add_include_dir_option,
                build_config.include_dir,
                flags,
                cc.compile_option,
                cc.output_to_option)

    def makefile_list(items):
        items = list(items) # force evaluation so we can slice it
        return (' '*16).join([item + ' \\\n' for item in items[:-1]] +
                             [items[-1]])

    def prefix_with_build_dir(path):
        if options.with_build_dir != None:
            return os.path.join(options.with_build_dir, path)
        return path

    def warning_flags(normal_flags,
                      maintainer_flags,
                      maintainer_mode):
        if maintainer_mode and maintainer_flags != '':
            return maintainer_flags
        return normal_flags

    return {
        'version_major':  build_config.version_major,
        'version_minor':  build_config.version_minor,
        'version_patch':  build_config.version_patch,
        'version_vc_rev': build_config.version_vc_rev,
        'so_abi_rev':     build_config.version_so_rev,
        'version':        build_config.version_string,

        'distribution_info': options.distribution_info,

        'version_datestamp': build_config.version_datestamp,

        'timestamp': build_config.timestamp(),
        'user':      build_config.username(),
        'hostname':  build_config.hostname(),
        'command_line': ' '.join(sys.argv),
        'local_config': slurp_file(options.local_config),
        'makefile_style': options.makefile_style or cc.makefile_style,

        'makefile_path': prefix_with_build_dir('Makefile'),

        'prefix': options.prefix or osinfo.install_root,
        'libdir': options.libdir or osinfo.lib_dir,
        'includedir': options.includedir or osinfo.header_dir,
        'docdir': options.docdir or osinfo.doc_dir,

        'build_dir': build_config.build_dir,
        'doc_output_dir': build_config.doc_output_dir,

        'build_doc_commands': build_config.build_doc_commands,

        'python_dir': build_config.python_dir,

        'os': options.os,
        'arch': options.arch,
        'submodel': options.cpu,

        'mp_bits': choose_mp_bits(),

        'cc': (options.compiler_binary or cc.binary_name) +
              cc.mach_abi_link_flags(options.os, options.arch,
                                     options.cpu, options.debug_build),

        'lib_opt': cc.library_opt_flags(options),
        'mach_opt': cc.mach_opts(options.arch, options.cpu),
        'check_opt': '' if options.no_optimizations else cc.check_opt_flags,
        'lang_flags': cc.lang_flags,
        'warn_flags': warning_flags(cc.warning_flags,
                                    cc.maintainer_warning_flags,
                                    options.maintainer_mode),

        'shared_flags': cc.gen_shared_flags(options),
        'visibility_attribute': cc.gen_visibility_attribute(options),

        'so_link': cc.so_link_command_for(osinfo.basename),

        'link_to': ' '.join([cc.add_lib_option + lib for lib in link_to()]),

        'module_defines': make_cpp_macros(sorted(flatten([m.defines() for m in modules]))),

        'target_os_defines': make_cpp_macros(osinfo.defines()),

        'target_compiler_defines': make_cpp_macros(cc.defines()),

        'target_cpu_defines': make_cpp_macros(arch.defines(options)),

        'include_files': makefile_list(build_config.public_headers),

        'lib_objs': makefile_list(
            objectfile_list(build_config.build_sources,
                            build_config.libobj_dir)),

        'check_objs': makefile_list(
            objectfile_list(build_config.check_sources,
                            build_config.checkobj_dir)),

        'lib_build_cmds': '\n'.join(
            build_commands(build_config.build_sources,
                           build_config.libobj_dir, 'LIB')),

        'check_build_cmds': '\n'.join(
            build_commands(build_config.check_sources,
                           build_config.checkobj_dir, 'CHECK')),

        'python_obj_dir': build_config.pyobject_dir,

        'python_objs': makefile_list(
            objectfile_list(build_config.python_sources,
                            build_config.pyobject_dir)),

        'python_build_cmds': '\n'.join(
            build_commands(build_config.python_sources,
                           build_config.pyobject_dir, 'PYTHON')),

        'ar_command': cc.ar_command or osinfo.ar_command,
        'ranlib_command': osinfo.ranlib_command(),
        'install_cmd_exec': osinfo.install_cmd_exec,
        'install_cmd_data': osinfo.install_cmd_data,

        'check_prefix': prefix_with_build_dir(''),
        'lib_prefix': prefix_with_build_dir(''),

        'static_suffix': osinfo.static_suffix,
        'so_suffix': osinfo.so_suffix,

        'botan_config': prefix_with_build_dir(
            os.path.join(build_config.build_dir,
                         build_config.config_shell_script())),

        'botan_pkgconfig': prefix_with_build_dir(
            os.path.join(build_config.build_dir,
                         build_config.pkg_config_file())),

        'mod_list': '\n'.join(sorted([m.basename for m in modules])),

        'python_version': options.python_version
        }

"""
Determine which modules to load based on options, target, etc
"""
def choose_modules_to_use(modules, archinfo, options):

    for mod in modules.values():
        mod.dependencies_exist(modules)

    to_load = []
    maybe_dep = []
    not_using_because = {}

    def cannot_use_because(mod, reason):
        not_using_because.setdefault(reason, []).append(mod)

    for modname in options.enabled_modules:
        if modname not in modules:
            logging.warning("Unknown enabled module %s" % (modname))

    for modname in options.disabled_modules:
        if modname not in modules:
            logging.warning("Unknown disabled module %s" % (modname))

    for (modname, module) in modules.items():
        if modname in options.disabled_modules:
            cannot_use_because(modname, 'disabled by user')
        elif modname in options.enabled_modules:
            to_load.append(modname) # trust the user

        elif not module.compatible_os(options.os):
            cannot_use_because(modname, 'incompatible OS')
        elif not module.compatible_compiler(options.compiler):
            cannot_use_because(modname, 'incompatible compiler')
        elif not module.compatible_cpu(archinfo, options):
            cannot_use_because(modname, 'incompatible CPU')

        else:
            if module.load_on == 'never':
                cannot_use_because(modname, 'disabled as buggy')
            elif module.load_on == 'request':
                cannot_use_because(modname, 'by request only')
            elif module.load_on == 'dep':
                maybe_dep.append(modname)

            elif module.load_on == 'always':
                to_load.append(modname)

            elif module.load_on == 'asm_ok':
                if options.asm_ok:
                    if options.no_autoload:
                        maybe_dep.append(modname)
                    else:
                        to_load.append(modname)
                else:
                    cannot_use_because(modname,
                                       'uses assembly and --disable-asm set')
            elif module.load_on == 'auto':
                if options.no_autoload:
                    maybe_dep.append(modname)
                else:
                    to_load.append(modname)
            else:
                logging.warning('Unknown load_on %s in %s' % (
                    module.load_on, modname))

    dependency_failure = True

    while dependency_failure:
        dependency_failure = False
        for modname in to_load:
            for deplist in [s.split('|') for s in modules[modname].dependencies()]:

                dep_met = False
                for mod in deplist:
                    if dep_met is True:
                        break

                    if mod in to_load:
                        dep_met = True
                    elif mod in maybe_dep:
                        maybe_dep.remove(mod)
                        to_load.append(mod)
                        dep_met = True

                if dep_met == False:
                    dependency_failure = True
                    if modname in to_load:
                        to_load.remove(modname)
                    if modname in maybe_dep:
                        maybe_dep.remove(modname)
                    cannot_use_because(modname, 'dependency failure')

    for not_a_dep in maybe_dep:
        cannot_use_because(not_a_dep, 'loaded only if needed by dependency')

    for reason in sorted(not_using_because.keys()):
        disabled_mods = sorted(set([mod for mod in not_using_because[reason]]))

        if disabled_mods != []:
            logging.info('Skipping, %s - %s' % (
                reason, ' '.join(disabled_mods)))

    for mod in sorted(to_load):
        if mod.startswith('mp_'):
            logging.info('Using MP module ' + mod)
        if mod.startswith('simd_') and mod != 'simd_engine':
            logging.info('Using SIMD module ' + mod)
        if modules[mod].comment:
            logging.info('%s: %s' % (mod, modules[mod].comment))

    logging.debug('Loading modules %s', ' '.join(sorted(to_load)))

    return [modules[mod] for mod in to_load]

"""
Load the info files about modules, targets, etc
"""
def load_info_files(options):

    def find_files_named(desired_name, in_path):
        for (dirpath, dirnames, filenames) in os.walk(in_path):
            if desired_name in filenames:
                yield os.path.join(dirpath, desired_name)

    modules = dict([(mod.basename, mod) for mod in
                    [ModuleInfo(info) for info in
                     find_files_named('info.txt', options.src_dir)]])

    def list_files_in_build_data(subdir):
        for (dirpath, dirnames, filenames) in \
                os.walk(os.path.join(options.build_data, subdir)):
            for filename in filenames:
                if filename.endswith('.txt'):
                    yield os.path.join(dirpath, filename)

    def form_name(filepath):
        return os.path.basename(filepath).replace('.txt', '')

    archinfo = dict([(form_name(info), ArchInfo(info))
                     for info in list_files_in_build_data('arch')])

    osinfo   = dict([(form_name(info), OsInfo(info))
                      for info in list_files_in_build_data('os')])

    ccinfo = dict([(form_name(info), CompilerInfo(info))
                    for info in list_files_in_build_data('cc')])

    def info_file_load_report(type, num):
        if num > 0:
            logging.debug('Loaded %d %s info files' % (num, type))
        else:
            logging.warning('Failed to load any %s info files' % (type))

    info_file_load_report('CPU', len(archinfo));
    info_file_load_report('OS', len(osinfo))
    info_file_load_report('compiler', len(ccinfo))

    return (modules, archinfo, ccinfo, osinfo)

"""
Perform the filesystem operations needed to setup the build
"""
def setup_build(build_config, options, template_vars):

    """
    Choose the link method based on system availablity and user request
    """
    def choose_link_method(req_method):

        def useable_methods():
            if 'symlink' in os.__dict__:
                yield 'symlink'
            if 'link' in os.__dict__:
                yield 'hardlink'
            yield 'copy'

        for method in useable_methods():
            if req_method is None or req_method == method:
                return method

        logging.info('Could not use requested link method %s' % (req_method))
        return 'copy'

    """
    Copy or link the file, depending on what the platform offers
    """
    def portable_symlink(filename, target_dir, method):

        if not os.access(filename, os.R_OK):
            logging.warning('Missing file %s' % (filename))
            return

        if method == 'symlink':
            def count_dirs(dir, accum = 0):
                if dir in ['', '/', os.path.curdir]:
                    return accum
                (dir,basename) = os.path.split(dir)
                return accum + 1 + count_dirs(dir)

            dirs_up = count_dirs(target_dir)

            source = os.path.join(os.path.join(*[os.path.pardir]*dirs_up),
                                  filename)

            target = os.path.join(target_dir, os.path.basename(filename))

            os.symlink(source, target)

        elif method == 'hardlink':
            os.link(filename,
                    os.path.join(target_dir, os.path.basename(filename)))

        elif method == 'copy':
            shutil.copy(filename, target_dir)

        else:
            raise Exception('Unknown link method %s' % (method))

    def choose_makefile_template(style):
        if style == 'nmake':
            return 'nmake.in'
        elif style == 'unix':
            return ('unix_shr.in' if options.build_shared_lib else 'unix.in')
        else:
            raise Exception('Unknown makefile style "%s"' % (style))

    # First delete the build tree, if existing
    try:
        if options.clean_build_tree:
            shutil.rmtree(build_config.build_dir)
    except OSError as e:
        if e.errno != errno.ENOENT:
            logging.error('Problem while removing build dir: %s' % (e))

    for dir in build_config.build_dirs:
        try:
            os.makedirs(dir)
        except OSError as e:
            if e.errno != errno.EEXIST:
                logging.error('Error while creating "%s": %s' % (dir, e))

    makefile_template = os.path.join(
        options.makefile_dir,
        choose_makefile_template(template_vars['makefile_style']))

    logging.debug('Using makefile template %s' % (makefile_template))

    templates_to_proc = {
        makefile_template: template_vars['makefile_path']
        }

    def templates_to_use():
        yield (options.build_data, 'buildh.in', 'build.h')
        yield (options.build_data, 'botan.doxy.in', 'botan.doxy')

        if options.os != 'windows':
            yield (options.build_data, 'botan.pc.in', build_config.pkg_config_file())
            yield (options.build_data, 'botan-config.in', build_config.config_shell_script())

        if options.os == 'windows':
            yield (options.build_data, 'innosetup.in', 'botan.iss')

        if options.boost_python:
            yield (options.makefile_dir, 'python.in', 'Makefile.python')

    for (template_dir, template, sink) in templates_to_use():
        source = os.path.join(template_dir, template)
        if template_dir == options.build_data:
            sink = os.path.join(build_config.build_dir, sink)
        templates_to_proc[source] = sink

    for (template, sink) in templates_to_proc.items():
        try:
            f = open(sink, 'w')
            f.write(process_template(template, template_vars))
        finally:
            f.close()

    link_method = choose_link_method(options.link_method)
    logging.info('Using %s to link files into build directory' % (link_method))

    def link_headers(header_list, type, dir):
        logging.debug('Linking %d %s header files in %s' % (
            len(header_list), type, dir))

        for header_file in header_list:
            try:
                portable_symlink(header_file, dir, link_method)
            except OSError as e:
                if e.errno != errno.EEXIST:
                    logging.error('Error linking %s into %s: %s' % (
                        header_file, dir, e))

    link_headers(build_config.public_headers, 'public',
                 build_config.botan_include_dir)

    link_headers(build_config.build_internal_headers, 'internal',
                 build_config.internal_include_dir)

"""
Generate Amalgamation
"""
def generate_amalgamation(build_config):
    def ending_with_suffix(suffix):
        def predicate(val):
            return val.endswith(suffix)
        return predicate

    def strip_header_goop(header_name, contents):
        header_guard = re.compile('^#define BOTAN_.*_H__$')

        while len(contents) > 0:
            if header_guard.match(contents[0]):
                contents = contents[1:]
                break

            contents = contents[1:]

        if len(contents) == 0:
            raise Exception("No header guard found in " + header_name)

        while contents[0] == '\n':
            contents = contents[1:]

        while contents[-1] == '\n':
            contents = contents[0:-1]
        if contents[-1] == '#endif\n':
            contents = contents[0:-1]

        return contents

    botan_include = re.compile('#include <botan/(.*)>$')
    std_include = re.compile('#include <([^/\.]+)>$')

    class Amalgamation_Generator:
        def __init__(self, input_list):

            self.included_already = set()
            self.all_std_includes = set()

            self.file_contents = {}
            for f in sorted(input_list):
                contents = strip_header_goop(f, open(f).readlines())
                self.file_contents[os.path.basename(f)] = contents

            self.contents = ''
            for name in self.file_contents:
                self.contents += ''.join(list(self.header_contents(name)))

            self.header_includes = ''
            for std_header in self.all_std_includes:
                self.header_includes += '#include <%s>\n' % (std_header)
            self.header_includes += '\n'

        def header_contents(self, name):
            name = name.replace('internal/', '')

            if name in self.included_already:
                return

            self.included_already.add(name)

            if name not in self.file_contents:
                return

            for line in self.file_contents[name]:
                match = botan_include.search(line)
                if match:
                    for c in self.header_contents(match.group(1)):
                        yield c
                else:
                    match = std_include.search(line)

                    if match and match.group(1) != 'functional':
                        self.all_std_includes.add(match.group(1))
                    else:
                        yield line

    amalg_basename = 'botan_all'

    header_name = '%s.h' % (amalg_basename)

    botan_h = open(header_name, 'w')

    pub_header_amalag = Amalgamation_Generator(build_config.public_headers)

    amalg_header = """/*
* Botan %s Amalgamation
* (C) 1999-2011 Jack Lloyd and others
*
* Distributed under the terms of the Botan license
*/
""" % (build_config.version_string)

    botan_h.write(amalg_header)

    botan_h.write("""
#ifndef BOTAN_AMALGAMATION_H__
#define BOTAN_AMALGAMATION_H__

""")

    botan_h.write(pub_header_amalag.header_includes)
    botan_h.write(pub_header_amalag.contents)
    botan_h.write("\n#endif\n")

    internal_header_amalag = Amalgamation_Generator(
        [s for s in build_config.internal_headers
         if s.find('asm_macr_') == -1])

    botan_cpp = open('%s.cpp' % (amalg_basename), 'w')

    botan_cpp.write(amalg_header)

    botan_cpp.write('\n#include "%s"\n' % (header_name))

    botan_cpp.write(internal_header_amalag.header_includes)
    botan_cpp.write(internal_header_amalag.contents)

    for src in build_config.sources:
        if src.endswith('.S'):
            continue

        contents = open(src).readlines()
        for line in contents:
            if botan_include.search(line):
                continue
            else:
                botan_cpp.write(line)

"""
Test for the existence of a program
"""
def have_program(program):

    def exe_test(path, program):
        exe_file = os.path.join(path, program)

        if os.path.exists(exe_file) and os.access(exe_file, os.X_OK):
            logging.debug('Found program %s in %s' % (program, path))
            return True
        else:
            return False

    exe_suffixes = ['', '.exe']

    for path in os.environ['PATH'].split(os.pathsep):
        for suffix in exe_suffixes:
            if exe_test(path, program + suffix):
                return True

    return False

"""
Main driver
"""
def main(argv = None):
    if argv is None:
        argv = sys.argv

    logging.basicConfig(stream = sys.stdout,
                        format = '%(levelname) 7s: %(message)s')

    options = process_command_line(argv[1:])

    def log_level():
        if options.verbose:
            return logging.DEBUG
        if options.quiet:
            return logging.WARNING
        return logging.INFO

    logging.getLogger().setLevel(log_level())

    logging.debug('%s invoked with options "%s"' % (
        argv[0], ' '.join(argv[1:])))

    logging.debug('Platform: OS="%s" machine="%s" proc="%s"' % (
        platform.system(), platform.machine(), platform.processor()))

    if options.os == "java":
        raise Exception("Jython detected: need --os and --cpu to set target")

    options.base_dir = os.path.dirname(argv[0])
    options.src_dir = os.path.join(options.base_dir, 'src')

    options.build_data = os.path.join(options.src_dir, 'build-data')
    options.makefile_dir = os.path.join(options.build_data, 'makefile')

    (modules, archinfo, ccinfo, osinfo) = load_info_files(options)

    if options.compiler is None:
        if options.os == 'windows':
            if have_program('g++') and not have_program('cl'):
                options.compiler = 'gcc'
            else:
                options.compiler = 'msvc'
        else:
            options.compiler = 'gcc'
        logging.info('Guessing to use compiler %s (use --cc to set)' % (
            options.compiler))

    if options.os is None:
        options.os = platform.system().lower()

        if re.match('^cygwin_.*', options.os):
            logging.debug("Converting '%s' to 'cygwin'", options.os)
            options.os = 'cygwin'

        if options.os == 'windows' and options.compiler == 'gcc':
            logging.warning('Detected GCC on Windows; use --os=cygwin or --os=mingw?')

        logging.info('Guessing target OS is %s (use --os to set)' % (options.os))

    if options.compiler not in ccinfo:
        raise Exception('Unknown compiler "%s"; available options: %s' % (
            options.compiler, ' '.join(sorted(ccinfo.keys()))))

    if options.os not in osinfo:

        def find_canonical_os_name(os):
            for (name, info) in osinfo.items():
                if os in info.aliases:
                    return name
            return os # not found

        options.os = find_canonical_os_name(options.os)

        if options.os not in osinfo:
            raise Exception('Unknown OS "%s"; available options: %s' % (
                options.os, ' '.join(sorted(osinfo.keys()))))

    if options.cpu is None:
        (options.arch, options.cpu) = guess_processor(archinfo)
        logging.info('Guessing target processor is a %s/%s (use --cpu to set)' % (
            options.arch, options.cpu))
    else:
        cpu_from_user = options.cpu
        (options.arch, options.cpu) = canon_processor(archinfo, options.cpu)
        logging.info('Canonicalizized --cpu=%s to %s/%s' % (
            cpu_from_user, options.arch, options.cpu))

    logging.info('Target is %s-%s-%s-%s' % (
        options.compiler, options.os, options.arch, options.cpu))

    cc = ccinfo[options.compiler]

    # Kind of a hack...
    if options.compiler == 'gcc':

        def get_gcc_version(gcc_bin):
            try:
                subproc_result = subprocess.Popen(
                    gcc_bin.split(' ') + ['-dumpversion'],
                    stdout=subprocess.PIPE,
                    stderr=subprocess.PIPE).communicate()

                gcc_version = ''.join(map(str, subproc_result)).strip()

                logging.info('Detected gcc version %s' % (gcc_version))
                return gcc_version
            except OSError:
                logging.warning('Could not execute %s for version check' % (gcc_bin))
                return None

        gcc_version = get_gcc_version(options.compiler_binary or cc.binary_name)

        if gcc_version:
            versions_without_cpp0x = '(4\.[01234]\.)|(3\.[0-4]\.)|(2\.95\.[0-4])'

            if re.search(versions_without_cpp0x, gcc_version):
                logging.info('This GCC is too old to compile C++0x')

    if options.with_visibility is None:
        options.with_visibility = True

    if options.with_sphinx is None:
        if have_program('sphinx-build'):
            logging.info('Found sphinx-build, will use it ' +
                         '(use --without-sphinx to disable)')
            options.with_sphinx = True

    if options.via_amalgamation:
        options.gen_amalgamation = True

    if options.gen_amalgamation:
        if options.asm_ok:
            logging.info('Disabling assembly code, cannot use in amalgamation')
            options.asm_ok = False

    modules_to_use = choose_modules_to_use(modules,
                                           archinfo[options.arch],
                                           options)

    if not osinfo[options.os].build_shared:
        if options.build_shared_lib:
            logging.info('Disabling shared lib on %s' % (options.os))
            options.build_shared_lib = False

    build_config = BuildConfigurationInformation(options, modules_to_use)
    build_config.public_headers.append(
        os.path.join(build_config.build_dir, 'build.h'))

    template_vars = create_template_vars(build_config, options,
                                         modules_to_use,
                                         cc,
                                         archinfo[options.arch],
                                         osinfo[options.os])

    # Performs the I/O
    setup_build(build_config, options, template_vars)

    if options.gen_amalgamation:
        generate_amalgamation(build_config)

    logging.info('Botan %s build setup is complete' % (
        build_config.version_string))

if __name__ == '__main__':
    try:
        main()
    except Exception as e:
        logging.error(str(e))
        #import traceback
        #traceback.print_exc(file=sys.stderr)
        sys.exit(1)
    sys.exit(0)