Merge the two verifiers into two VEngine classes. There is still a little bit

of code duplication but not too much.

7 files changed, 1380 insertions, 559 deletions

diff --git a/cffi/vengine_cpy.py b/cffi/vengine_cpy.py
new file mode 100644
index 0000000..3ee3140
--- /dev/null
+++ b/cffi/vengine_cpy.py
@@ -0,0 +1,729 @@
+import imp
+from . import model, ffiplatform
+
+
+class VCPythonEngine(object):
+    _class_key = 'x'
+    _gen_python_module = True
+
+    def __init__(self, verifier):
+        self.verifier = verifier
+        self.ffi = verifier.ffi
+
+    def collect_types(self):
+        self._typesdict = {}
+        self._generate("collecttype")
+
+    def _prnt(self, what=''):
+        print >> self._f, what
+
+    def _gettypenum(self, type):
+        # a KeyError here is a bug.  please report it! :-)
+        return self._typesdict[type]
+
+    def _do_collect_type(self, tp):
+        if (not isinstance(tp, model.PrimitiveType) and
+                tp not in self._typesdict):
+            num = len(self._typesdict)
+            self._typesdict[tp] = num
+
+    def write_source_to_f(self):
+        self.collect_types()
+        #
+        # The new module will have a _cffi_setup() function that receives
+        # objects from the ffi world, and that calls some setup code in
+        # the module.  This setup code is split in several independent
+        # functions, e.g. one per constant.  The functions are "chained"
+        # by ending in a tail call to each other.
+        #
+        # This is further split in two chained lists, depending on if we
+        # can do it at import-time or if we must wait for _cffi_setup() to
+        # provide us with the <ctype> objects.  This is needed because we
+        # need the values of the enum constants in order to build the
+        # <ctype 'enum'> that we may have to pass to _cffi_setup().
+        #
+        # The following two 'chained_list_constants' items contains
+        # the head of these two chained lists, as a string that gives the
+        # call to do, if any.
+        self._chained_list_constants = ['0', '0']
+        #
+        prnt = self._prnt
+        # first paste some standard set of lines that are mostly '#define'
+        prnt(cffimod_header)
+        prnt()
+        # then paste the C source given by the user, verbatim.
+        prnt(self.verifier.preamble)
+        prnt()
+        #
+        # call generate_cpy_xxx_decl(), for every xxx found from
+        # ffi._parser._declarations.  This generates all the functions.
+        self._generate("decl")
+        #
+        # implement the function _cffi_setup_custom() as calling the
+        # head of the chained list.
+        self._generate_setup_custom()
+        prnt()
+        #
+        # produce the method table, including the entries for the
+        # generated Python->C function wrappers, which are done
+        # by generate_cpy_function_method().
+        prnt('static PyMethodDef _cffi_methods[] = {')
+        self._generate("method")
+        prnt('  {"_cffi_setup", _cffi_setup, METH_VARARGS},')
+        prnt('  {NULL, NULL}    /* Sentinel */')
+        prnt('};')
+        prnt()
+        #
+        # standard init.
+        modname = self.verifier.get_module_name()
+        prnt('PyMODINIT_FUNC')
+        prnt('init%s(void)' % modname)
+        prnt('{')
+        prnt('  PyObject *lib;')
+        prnt('  lib = Py_InitModule("%s", _cffi_methods);' % modname)
+        prnt('  if (lib == NULL || %s < 0)' % (
+            self._chained_list_constants[False],))
+        prnt('    return;')
+        prnt('  _cffi_init();')
+        prnt('}')
+
+    def load_library(self):
+        # XXX review all usages of 'self' here!
+        # import it as a new extension module
+        try:
+            module = imp.load_dynamic(self.verifier.get_module_name(),
+                                      self.verifier.modulefilename)
+        except ImportError, e:
+            error = "importing %r: %s" % (self.modulefilename, e)
+            raise ffiplatform.VerificationError(error)
+        #
+        # call loading_cpy_struct() to get the struct layout inferred by
+        # the C compiler
+        self._load(module, 'loading')
+        #
+        # the C code will need the <ctype> objects.  Collect them in
+        # order in a list.
+        revmapping = dict([(value, key)
+                           for (key, value) in self._typesdict.items()])
+        lst = [revmapping[i] for i in range(len(revmapping))]
+        lst = map(self.ffi._get_cached_btype, lst)
+        #
+        # build the FFILibrary class and instance and call _cffi_setup().
+        # this will set up some fields like '_cffi_types', and only then
+        # it will invoke the chained list of functions that will really
+        # build (notably) the constant objects, as <cdata> if they are
+        # pointers, and store them as attributes on the 'library' object.
+        class FFILibrary(object):
+            _cffi_python_module = module
+        library = FFILibrary()
+        module._cffi_setup(lst, ffiplatform.VerificationError, library)
+        #
+        # finally, call the loaded_cpy_xxx() functions.  This will perform
+        # the final adjustments, like copying the Python->C wrapper
+        # functions from the module to the 'library' object, and setting
+        # up the FFILibrary class with properties for the global C variables.
+        self._load(module, 'loaded', library=library)
+        return library
+
+    def _generate(self, step_name):
+        for name, tp in self.ffi._parser._declarations.iteritems():
+            kind, realname = name.split(' ', 1)
+            try:
+                method = getattr(self, '_generate_cpy_%s_%s' % (kind,
+                                                                step_name))
+            except AttributeError:
+                raise ffiplatform.VerificationError(
+                    "not implemented in verify(): %r" % name)
+            method(tp, realname)
+
+    def _load(self, module, step_name, **kwds):
+        for name, tp in self.ffi._parser._declarations.iteritems():
+            kind, realname = name.split(' ', 1)
+            method = getattr(self, '_%s_cpy_%s' % (step_name, kind))
+            method(tp, realname, module, **kwds)
+
+    def _generate_nothing(self, tp, name):
+        pass
+
+    def _loaded_noop(self, tp, name, module, **kwds):
+        pass
+
+    # ----------
+
+    def _convert_funcarg_to_c(self, tp, fromvar, tovar, errcode):
+        extraarg = ''
+        if isinstance(tp, model.PrimitiveType):
+            converter = '_cffi_to_c_%s' % (tp.name.replace(' ', '_'),)
+            errvalue = '-1'
+        #
+        elif isinstance(tp, model.PointerType):
+            if (isinstance(tp.totype, model.PrimitiveType) and
+                    tp.totype.name == 'char'):
+                converter = '_cffi_to_c_char_p'
+            else:
+                converter = '(%s)_cffi_to_c_pointer' % tp.get_c_name('')
+                extraarg = ', _cffi_type(%d)' % self._gettypenum(tp)
+            errvalue = 'NULL'
+        #
+        elif isinstance(tp, (model.StructOrUnion, model.EnumType)):
+            # a struct (not a struct pointer) as a function argument
+            self._prnt('  if (_cffi_to_c((char *)&%s, _cffi_type(%d), %s) < 0)'
+                      % (tovar, self._gettypenum(tp), fromvar))
+            self._prnt('    %s;' % errcode)
+            return
+        #
+        elif isinstance(tp, model.FunctionPtrType):
+            converter = '(%s)_cffi_to_c_pointer' % tp.get_c_name('')
+            extraarg = ', _cffi_type(%d)' % self._gettypenum(tp)
+            errvalue = 'NULL'
+        #
+        else:
+            raise NotImplementedError(tp)
+        #
+        self._prnt('  %s = %s(%s%s);' % (tovar, converter, fromvar, extraarg))
+        self._prnt('  if (%s == (%s)%s && PyErr_Occurred())' % (
+            tovar, tp.get_c_name(''), errvalue))
+        self._prnt('    %s;' % errcode)
+
+    def _convert_expr_from_c(self, tp, var):
+        if isinstance(tp, model.PrimitiveType):
+            return '_cffi_from_c_%s(%s)' % (tp.name.replace(' ', '_'), var)
+        elif isinstance(tp, (model.PointerType, model.FunctionPtrType)):
+            return '_cffi_from_c_pointer((char *)%s, _cffi_type(%d))' % (
+                var, self._gettypenum(tp))
+        elif isinstance(tp, model.ArrayType):
+            return '_cffi_from_c_deref((char *)%s, _cffi_type(%d))' % (
+                var, self._gettypenum(tp))
+        elif isinstance(tp, model.StructType):
+            return '_cffi_from_c_struct((char *)&%s, _cffi_type(%d))' % (
+                var, self._gettypenum(tp))
+        elif isinstance(tp, model.EnumType):
+            return '_cffi_from_c_deref((char *)&%s, _cffi_type(%d))' % (
+                var, self._gettypenum(tp))
+        else:
+            raise NotImplementedError(tp)
+
+    # ----------
+    # typedefs: generates no code so far
+
+    _generate_cpy_typedef_collecttype = _generate_nothing
+    _generate_cpy_typedef_decl   = _generate_nothing
+    _generate_cpy_typedef_method = _generate_nothing
+    _loading_cpy_typedef         = _loaded_noop
+    _loaded_cpy_typedef          = _loaded_noop
+
+    # ----------
+    # function declarations
+
+    def _generate_cpy_function_collecttype(self, tp, name):
+        assert isinstance(tp, model.FunctionPtrType)
+        if tp.ellipsis:
+            self._do_collect_type(tp)
+        else:
+            for type in tp.args:
+                self._do_collect_type(type)
+            self._do_collect_type(tp.result)
+
+    def _generate_cpy_function_decl(self, tp, name):
+        assert isinstance(tp, model.FunctionPtrType)
+        if tp.ellipsis:
+            # cannot support vararg functions better than this: check for its
+            # exact type (including the fixed arguments), and build it as a
+            # constant function pointer (no CPython wrapper)
+            self._generate_cpy_const(False, name, tp)
+            return
+        prnt = self._prnt
+        numargs = len(tp.args)
+        if numargs == 0:
+            argname = 'no_arg'
+        elif numargs == 1:
+            argname = 'arg0'
+        else:
+            argname = 'args'
+        prnt('static PyObject *')
+        prnt('_cffi_f_%s(PyObject *self, PyObject *%s)' % (name, argname))
+        prnt('{')
+        #
+        for i, type in enumerate(tp.args):
+            prnt('  %s;' % type.get_c_name(' x%d' % i))
+        if not isinstance(tp.result, model.VoidType):
+            result_code = 'result = '
+            prnt('  %s;' % tp.result.get_c_name(' result'))
+        else:
+            result_code = ''
+        #
+        if len(tp.args) > 1:
+            rng = range(len(tp.args))
+            for i in rng:
+                prnt('  PyObject *arg%d;' % i)
+            prnt()
+            prnt('  if (!PyArg_ParseTuple(args, "%s:%s", %s))' % (
+                'O' * numargs, name, ', '.join(['&arg%d' % i for i in rng])))
+            prnt('    return NULL;')
+        prnt()
+        #
+        for i, type in enumerate(tp.args):
+            self._convert_funcarg_to_c(type, 'arg%d' % i, 'x%d' % i,
+                                       'return NULL')
+            prnt()
+        #
+        prnt('  Py_BEGIN_ALLOW_THREADS')
+        prnt('  _cffi_restore_errno();')
+        prnt('  { %s%s(%s); }' % (
+            result_code, name,
+            ', '.join(['x%d' % i for i in range(len(tp.args))])))
+        prnt('  _cffi_save_errno();')
+        prnt('  Py_END_ALLOW_THREADS')
+        prnt()
+        #
+        if result_code:
+            prnt('  return %s;' %
+                 self._convert_expr_from_c(tp.result, 'result'))
+        else:
+            prnt('  Py_INCREF(Py_None);')
+            prnt('  return Py_None;')
+        prnt('}')
+        prnt()
+
+    def _generate_cpy_function_method(self, tp, name):
+        if tp.ellipsis:
+            return
+        numargs = len(tp.args)
+        if numargs == 0:
+            meth = 'METH_NOARGS'
+        elif numargs == 1:
+            meth = 'METH_O'
+        else:
+            meth = 'METH_VARARGS'
+        self._prnt('  {"%s", _cffi_f_%s, %s},' % (name, name, meth))
+
+    _loading_cpy_function = _loaded_noop
+
+    def _loaded_cpy_function(self, tp, name, module, library):
+        if tp.ellipsis:
+            return
+        setattr(library, name, getattr(module, name))
+
+    # ----------
+    # named structs
+
+    _generate_cpy_struct_collecttype = _generate_nothing
+
+    def _generate_cpy_struct_decl(self, tp, name):
+        assert name == tp.name
+        self._generate_struct_or_union_decl(tp, 'struct', name)
+
+    def _generate_cpy_struct_method(self, tp, name):
+        self._generate_struct_or_union_method(tp, 'struct', name)
+
+    def _loading_cpy_struct(self, tp, name, module):
+        self._loading_struct_or_union(tp, 'struct', name, module)
+
+    def _loaded_cpy_struct(self, tp, name, module, **kwds):
+        self._loaded_struct_or_union(tp)
+
+    def _generate_struct_or_union_decl(self, tp, prefix, name):
+        if tp.fldnames is None:
+            return     # nothing to do with opaque structs
+        checkfuncname = '_cffi_check_%s_%s' % (prefix, name)
+        layoutfuncname = '_cffi_layout_%s_%s' % (prefix, name)
+        cname = ('%s %s' % (prefix, name)).strip()
+        #
+        prnt = self._prnt
+        prnt('static void %s(%s *p)' % (checkfuncname, cname))
+        prnt('{')
+        prnt('  /* only to generate compile-time warnings or errors */')
+        for i in range(len(tp.fldnames)):
+            fname = tp.fldnames[i]
+            ftype = tp.fldtypes[i]
+            if (isinstance(ftype, model.PrimitiveType)
+                and ftype.is_integer_type()):
+                # accept all integers, but complain on float or double
+                prnt('  (void)((p->%s) << 1);' % fname)
+            else:
+                # only accept exactly the type declared.  Note the parentheses
+                # around the '*tmp' below.  In most cases they are not needed
+                # but don't hurt --- except test_struct_array_field.
+                prnt('  { %s = &p->%s; (void)tmp; }' % (
+                    ftype.get_c_name('(*tmp)'), fname))
+        prnt('}')
+        prnt('static PyObject *')
+        prnt('%s(PyObject *self, PyObject *noarg)' % (layoutfuncname,))
+        prnt('{')
+        prnt('  struct _cffi_aligncheck { char x; %s y; };' % cname)
+        if tp.partial:
+            prnt('  static Py_ssize_t nums[] = {')
+            prnt('    sizeof(%s),' % cname)
+            prnt('    offsetof(struct _cffi_aligncheck, y),')
+            for fname in tp.fldnames:
+                prnt('    offsetof(%s, %s),' % (cname, fname))
+                prnt('    sizeof(((%s *)0)->%s),' % (cname, fname))
+            prnt('    -1')
+            prnt('  };')
+            prnt('  return _cffi_get_struct_layout(nums);')
+        else:
+            ffi = self.ffi
+            BStruct = ffi._get_cached_btype(tp)
+            conditions = [
+                'sizeof(%s) != %d' % (cname, ffi.sizeof(BStruct)),
+                'offsetof(struct _cffi_aligncheck, y) != %d' % (
+                    ffi.alignof(BStruct),)]
+            for fname, ftype in zip(tp.fldnames, tp.fldtypes):
+                BField = ffi._get_cached_btype(ftype)
+                conditions += [
+                    'offsetof(%s, %s) != %d' % (
+                        cname, fname, ffi.offsetof(BStruct, fname)),
+                    'sizeof(((%s *)0)->%s) != %d' % (
+                        cname, fname, ffi.sizeof(BField))]
+            prnt('  if (%s ||' % conditions[0])
+            for i in range(1, len(conditions)-1):
+                prnt('      %s ||' % conditions[i])
+            prnt('      %s) {' % conditions[-1])
+            prnt('    Py_INCREF(Py_False);')
+            prnt('    return Py_False;')
+            prnt('  }')
+            prnt('  else {')
+            prnt('    Py_INCREF(Py_True);')
+            prnt('    return Py_True;')
+            prnt('  }')
+        prnt('  /* the next line is not executed, but compiled */')
+        prnt('  %s(0);' % (checkfuncname,))
+        prnt('}')
+        prnt()
+
+    def _generate_struct_or_union_method(self, tp, prefix, name):
+        if tp.fldnames is None:
+            return     # nothing to do with opaque structs
+        layoutfuncname = '_cffi_layout_%s_%s' % (prefix, name)
+        self._prnt('  {"%s", %s, METH_NOARGS},' % (layoutfuncname,
+                                                   layoutfuncname))
+
+    def _loading_struct_or_union(self, tp, prefix, name, module):
+        if tp.fldnames is None:
+            return     # nothing to do with opaque structs
+        layoutfuncname = '_cffi_layout_%s_%s' % (prefix, name)
+        cname = ('%s %s' % (prefix, name)).strip()
+        #
+        function = getattr(module, layoutfuncname)
+        layout = function()
+        if layout is False:
+            raise ffiplatform.VerificationError(
+                "incompatible layout for %s" % cname)
+        elif layout is True:
+            assert not tp.partial
+        else:
+            totalsize = layout[0]
+            totalalignment = layout[1]
+            fieldofs = layout[2::2]
+            fieldsize = layout[3::2]
+            assert len(fieldofs) == len(fieldsize) == len(tp.fldnames)
+            tp.fixedlayout = fieldofs, fieldsize, totalsize, totalalignment
+
+    def _loaded_struct_or_union(self, tp):
+        if tp.fldnames is None:
+            return     # nothing to do with opaque structs
+        self.ffi._get_cached_btype(tp)   # force 'fixedlayout' to be considered
+
+    # ----------
+    # 'anonymous' declarations.  These are produced for anonymous structs
+    # or unions; the 'name' is obtained by a typedef.
+
+    _generate_cpy_anonymous_collecttype = _generate_nothing
+
+    def _generate_cpy_anonymous_decl(self, tp, name):
+        self._generate_struct_or_union_decl(tp, '', name)
+
+    def _generate_cpy_anonymous_method(self, tp, name):
+        self._generate_struct_or_union_method(tp, '', name)
+
+    def _loading_cpy_anonymous(self, tp, name, module):
+        self._loading_struct_or_union(tp, '', name, module)
+
+    def _loaded_cpy_anonymous(self, tp, name, module, **kwds):
+        self._loaded_struct_or_union(tp)
+
+    # ----------
+    # constants, likely declared with '#define'
+
+    def _generate_cpy_const(self, is_int, name, tp=None, category='const',
+                            vartp=None, delayed=True):
+        prnt = self._prnt
+        funcname = '_cffi_%s_%s' % (category, name)
+        prnt('static int %s(PyObject *lib)' % funcname)
+        prnt('{')
+        prnt('  PyObject *o;')
+        prnt('  int res;')
+        if not is_int:
+            prnt('  %s;' % (vartp or tp).get_c_name(' i'))
+        else:
+            assert category == 'const'
+        #
+        if not is_int:
+            if category == 'var':
+                realexpr = '&' + name
+            else:
+                realexpr = name
+            prnt('  i = (%s);' % (realexpr,))
+            prnt('  o = %s;' % (self._convert_expr_from_c(tp, 'i'),))
+            assert delayed
+        else:
+            prnt('  if (LONG_MIN <= (%s) && (%s) <= LONG_MAX)' % (name, name))
+            prnt('    o = PyInt_FromLong((long)(%s));' % (name,))
+            prnt('  else if ((%s) <= 0)' % (name,))
+            prnt('    o = PyLong_FromLongLong((long long)(%s));' % (name,))
+            prnt('  else')
+            prnt('    o = PyLong_FromUnsignedLongLong('
+                 '(unsigned long long)(%s));' % (name,))
+        prnt('  if (o == NULL)')
+        prnt('    return -1;')
+        prnt('  res = PyObject_SetAttrString(lib, "%s", o);' % name)
+        prnt('  Py_DECREF(o);')
+        prnt('  if (res < 0)')
+        prnt('    return -1;')
+        prnt('  return %s;' % self._chained_list_constants[delayed])
+        self._chained_list_constants[delayed] = funcname + '(lib)'
+        prnt('}')
+        prnt()
+
+    def _generate_cpy_constant_collecttype(self, tp, name):
+        is_int = isinstance(tp, model.PrimitiveType) and tp.is_integer_type()
+        if not is_int:
+            self._do_collect_type(tp)
+
+    def _generate_cpy_constant_decl(self, tp, name):
+        is_int = isinstance(tp, model.PrimitiveType) and tp.is_integer_type()
+        self._generate_cpy_const(is_int, name, tp)
+
+    _generate_cpy_constant_method = _generate_nothing
+    _loading_cpy_constant = _loaded_noop
+    _loaded_cpy_constant  = _loaded_noop
+
+    # ----------
+    # enums
+
+    def _generate_cpy_enum_decl(self, tp, name):
+        if tp.partial:
+            for enumerator in tp.enumerators:
+                self._generate_cpy_const(True, enumerator, delayed=False)
+            return
+        #
+        funcname = '_cffi_enum_%s' % name
+        prnt = self._prnt
+        prnt('static int %s(PyObject *lib)' % funcname)
+        prnt('{')
+        for enumerator, enumvalue in zip(tp.enumerators, tp.enumvalues):
+            prnt('  if (%s != %d) {' % (enumerator, enumvalue))
+            prnt('    PyErr_Format(_cffi_VerificationError,')
+            prnt('                 "in enum %s: %s has the real value %d, '
+                 'not %d",')
+            prnt('                 "%s", "%s", (int)%s, %d);' % (
+                name, enumerator, enumerator, enumvalue))
+            prnt('    return -1;')
+            prnt('  }')
+        prnt('  return %s;' % self._chained_list_constants[True])
+        self._chained_list_constants[True] = funcname + '(lib)'
+        prnt('}')
+        prnt()
+
+    _generate_cpy_enum_collecttype = _generate_nothing
+    _generate_cpy_enum_method = _generate_nothing
+    _loading_cpy_enum = _loaded_noop
+
+    def _loading_cpy_enum(self, tp, name, module):
+        if tp.partial:
+            enumvalues = [getattr(module, enumerator)
+                          for enumerator in tp.enumerators]
+            tp.enumvalues = tuple(enumvalues)
+            tp.partial = False
+
+    def _loaded_cpy_enum(self, tp, name, module, library):
+        for enumerator, enumvalue in zip(tp.enumerators, tp.enumvalues):
+            setattr(library, enumerator, enumvalue)
+
+    # ----------
+    # macros: for now only for integers
+
+    def _generate_cpy_macro_decl(self, tp, name):
+        assert tp == '...'
+        self._generate_cpy_const(True, name)
+
+    _generate_cpy_macro_collecttype = _generate_nothing
+    _generate_cpy_macro_method = _generate_nothing
+    _loading_cpy_macro = _loaded_noop
+    _loaded_cpy_macro  = _loaded_noop
+
+    # ----------
+    # global variables
+
+    def _generate_cpy_variable_collecttype(self, tp, name):
+        if isinstance(tp, model.ArrayType):
+            self._do_collect_type(tp)
+        else:
+            tp_ptr = model.PointerType(tp)
+            self._do_collect_type(tp_ptr)
+
+    def _generate_cpy_variable_decl(self, tp, name):
+        if isinstance(tp, model.ArrayType):
+            tp_ptr = model.PointerType(tp.item)
+            self._generate_cpy_const(False, name, tp, vartp=tp_ptr)
+        else:
+            tp_ptr = model.PointerType(tp)
+            self._generate_cpy_const(False, name, tp_ptr, category='var')
+
+    _generate_cpy_variable_method = _generate_nothing
+    _loading_cpy_variable = _loaded_noop
+
+    def _loaded_cpy_variable(self, tp, name, module, library):
+        if isinstance(tp, model.ArrayType):   # int a[5] is "constant" in the
+            return                            # sense that "a=..." is forbidden
+        # remove ptr=<cdata 'int *'> from the library instance, and replace
+        # it by a property on the class, which reads/writes into ptr[0].
+        ptr = getattr(library, name)
+        delattr(library, name)
+        def getter(library):
+            return ptr[0]
+        def setter(library, value):
+            ptr[0] = value
+        setattr(library.__class__, name, property(getter, setter))
+
+    # ----------
+
+    def _generate_setup_custom(self):
+        prnt = self._prnt
+        prnt('static PyObject *_cffi_setup_custom(PyObject *lib)')
+        prnt('{')
+        prnt('  if (%s < 0)' % self._chained_list_constants[True])
+        prnt('    return NULL;')
+        prnt('  Py_INCREF(Py_None);')
+        prnt('  return Py_None;')
+        prnt('}')
+
+cffimod_header = r'''
+#include <Python.h>
+#include <stddef.h>
+
+#define _cffi_from_c_double PyFloat_FromDouble
+#define _cffi_from_c_float PyFloat_FromDouble
+#define _cffi_from_c_signed_char PyInt_FromLong
+#define _cffi_from_c_short PyInt_FromLong
+#define _cffi_from_c_int PyInt_FromLong
+#define _cffi_from_c_long PyInt_FromLong
+#define _cffi_from_c_unsigned_char PyInt_FromLong
+#define _cffi_from_c_unsigned_short PyInt_FromLong
+#define _cffi_from_c_unsigned_long PyLong_FromUnsignedLong
+#define _cffi_from_c_unsigned_long_long PyLong_FromUnsignedLongLong
+
+#if SIZEOF_INT < SIZEOF_LONG
+#  define _cffi_from_c_unsigned_int PyInt_FromLong
+#else
+#  define _cffi_from_c_unsigned_int PyLong_FromUnsignedLong
+#endif
+
+#if SIZEOF_LONG < SIZEOF_LONG_LONG
+#  define _cffi_from_c_long_long PyLong_FromLongLong
+#else
+#  define _cffi_from_c_long_long PyInt_FromLong
+#endif
+
+#define _cffi_to_c_long PyInt_AsLong
+#define _cffi_to_c_double PyFloat_AsDouble
+#define _cffi_to_c_float PyFloat_AsDouble
+
+#define _cffi_to_c_char_p                                                \
+                 ((char *(*)(PyObject *))_cffi_exports[0])
+#define _cffi_to_c_signed_char                                           \
+                 ((signed char(*)(PyObject *))_cffi_exports[1])
+#define _cffi_to_c_unsigned_char                                         \
+                 ((unsigned char(*)(PyObject *))_cffi_exports[2])
+#define _cffi_to_c_short                                                 \
+                 ((short(*)(PyObject *))_cffi_exports[3])
+#define _cffi_to_c_unsigned_short                                        \
+                 ((unsigned short(*)(PyObject *))_cffi_exports[4])
+
+#if SIZEOF_INT < SIZEOF_LONG
+#  define _cffi_to_c_int                                                 \
+                   ((int(*)(PyObject *))_cffi_exports[5])
+#  define _cffi_to_c_unsigned_int                                        \
+                   ((unsigned int(*)(PyObject *))_cffi_exports[6])
+#else
+#  define _cffi_to_c_int          _cffi_to_c_long
+#  define _cffi_to_c_unsigned_int _cffi_to_c_unsigned_long
+#endif
+
+#define _cffi_to_c_unsigned_long                                         \
+                 ((unsigned long(*)(PyObject *))_cffi_exports[7])
+#define _cffi_to_c_unsigned_long_long                                    \
+                 ((unsigned long long(*)(PyObject *))_cffi_exports[8])
+#define _cffi_to_c_char                                                  \
+                 ((char(*)(PyObject *))_cffi_exports[9])
+#define _cffi_from_c_pointer                                             \
+    ((PyObject *(*)(char *, CTypeDescrObject *))_cffi_exports[10])
+#define _cffi_to_c_pointer                                               \
+    ((char *(*)(PyObject *, CTypeDescrObject *))_cffi_exports[11])
+#define _cffi_get_struct_layout                                          \
+    ((PyObject *(*)(Py_ssize_t[]))_cffi_exports[12])
+#define _cffi_restore_errno                                              \
+    ((void(*)(void))_cffi_exports[13])
+#define _cffi_save_errno                                                 \
+    ((void(*)(void))_cffi_exports[14])
+#define _cffi_from_c_char                                                \
+    ((PyObject *(*)(char))_cffi_exports[15])
+#define _cffi_from_c_deref                                               \
+    ((PyObject *(*)(char *, CTypeDescrObject *))_cffi_exports[16])
+#define _cffi_to_c                                                       \
+    ((int(*)(char *, CTypeDescrObject *, PyObject *))_cffi_exports[17])
+#define _cffi_from_c_struct                                              \
+    ((PyObject *(*)(char *, CTypeDescrObject *))_cffi_exports[18])
+#define _cffi_to_c_wchar_t                                               \
+                 ((wchar_t(*)(PyObject *))_cffi_exports[19])
+#define _cffi_from_c_wchar_t                                             \
+    ((PyObject *(*)(wchar_t))_cffi_exports[20])
+#define _CFFI_NUM_EXPORTS 21
+
+#if SIZEOF_LONG < SIZEOF_LONG_LONG
+#  define _cffi_to_c_long_long PyLong_AsLongLong
+#else
+#  define _cffi_to_c_long_long _cffi_to_c_long
+#endif
+
+typedef struct _ctypedescr CTypeDescrObject;
+
+static void *_cffi_exports[_CFFI_NUM_EXPORTS];
+static PyObject *_cffi_types, *_cffi_VerificationError;
+
+static PyObject *_cffi_setup_custom(PyObject *lib);   /* forward */
+
+static PyObject *_cffi_setup(PyObject *self, PyObject *args)
+{
+    PyObject *library;
+    if (!PyArg_ParseTuple(args, "OOO", &_cffi_types, &_cffi_VerificationError,
+                                       &library))
+        return NULL;
+    Py_INCREF(_cffi_types);
+    Py_INCREF(_cffi_VerificationError);
+    return _cffi_setup_custom(library);
+}
+
+static void _cffi_init(void)
+{
+    PyObject *module = PyImport_ImportModule("_cffi_backend");
+    PyObject *c_api_object;
+
+    if (module == NULL)
+        return;
+
+    c_api_object = PyObject_GetAttrString(module, "_C_API");
+    if (c_api_object == NULL)
+        return;
+    if (!PyCObject_Check(c_api_object)) {
+        PyErr_SetNone(PyExc_ImportError);
+        return;
+    }
+    memcpy(_cffi_exports, PyCObject_AsVoidPtr(c_api_object),
+           _CFFI_NUM_EXPORTS * sizeof(void *));
+}
+
+#define _cffi_type(num) ((CTypeDescrObject *)PyList_GET_ITEM(_cffi_types, num))
+
+/**********/
+'''
diff --git a/cffi/vengine_gen.py b/cffi/vengine_gen.py
new file mode 100644
index 0000000..68b9224
--- /dev/null
+++ b/cffi/vengine_gen.py
@@ -0,0 +1,420 @@
+import sys, os, binascii, imp, shutil
+from . import model, ffiplatform
+
+
+class VGenericEngine(object):
+    _class_key = 'g'
+    _gen_python_module = False
+
+    def __init__(self, verifier):
+        self.verifier = verifier
+        self.ffi = verifier.ffi
+
+    def collect_types(self):
+        pass      # not needed in the generic engine
+
+    def _prnt(self, what=''):
+        print >> self._f, what
+
+    def write_source_to_f(self):
+        prnt = self._prnt
+        # first paste some standard set of lines that are mostly '#include'
+        prnt(cffimod_header)
+        # then paste the C source given by the user, verbatim.
+        prnt(self.verifier.preamble)
+        #
+        # call generate_gen_xxx_decl(), for every xxx found from
+        # ffi._parser._declarations.  This generates all the functions.
+        self._generate('decl')
+
+    def load_library(self):
+        # import it with the CFFI backend
+        backend = self.ffi._backend
+        module = backend.load_library(self.verifier.modulefilename)
+        #
+        # call loading_gen_struct() to get the struct layout inferred by
+        # the C compiler
+        self._load(module, 'loading')
+        #
+        # build the FFILibrary class and instance
+        class FFILibrary(object):
+            _cffi_generic_module = module
+        library = FFILibrary()
+        #
+        # finally, call the loaded_gen_xxx() functions.  This will set
+        # up the 'library' object.
+        self._load(module, 'loaded', library=library)
+        return library
+
+    def _generate(self, step_name):
+        for name, tp in self.ffi._parser._declarations.iteritems():
+            kind, realname = name.split(' ', 1)
+            try:
+                method = getattr(self, '_generate_gen_%s_%s' % (kind,
+                                                                step_name))
+            except AttributeError:
+                raise ffiplatform.VerificationError(
+                    "not implemented in verify(): %r" % name)
+            method(tp, realname)
+
+    def _load(self, module, step_name, **kwds):
+        for name, tp in self.ffi._parser._declarations.iteritems():
+            kind, realname = name.split(' ', 1)
+            method = getattr(self, '_%s_gen_%s' % (step_name, kind))
+            method(tp, realname, module, **kwds)
+
+    def _generate_nothing(self, tp, name):
+        pass
+
+    def _loaded_noop(self, tp, name, module, **kwds):
+        pass
+
+    # ----------
+    # typedefs: generates no code so far
+
+    _generate_gen_typedef_decl   = _generate_nothing
+    _loading_gen_typedef         = _loaded_noop
+    _loaded_gen_typedef          = _loaded_noop
+
+    # ----------
+    # function declarations
+
+    def _generate_gen_function_decl(self, tp, name):
+        assert isinstance(tp, model.FunctionPtrType)
+        if tp.ellipsis:
+            # cannot support vararg functions better than this: check for its
+            # exact type (including the fixed arguments), and build it as a
+            # constant function pointer (no _cffi_f_%s wrapper)
+            self._generate_gen_const(False, name, tp)
+            return
+        prnt = self._prnt
+        numargs = len(tp.args)
+        argnames = []
+        for i, type in enumerate(tp.args):
+            indirection = ''
+            if isinstance(type, model.StructOrUnion):
+                indirection = '*'
+            argnames.append('%sx%d' % (indirection, i))
+        arglist = [type.get_c_name(' %s' % arg)
+                   for type, arg in zip(tp.args, argnames)]
+        arglist = ', '.join(arglist) or 'void'
+        funcdecl = ' _cffi_f_%s(%s)' % (name, arglist)
+        prnt(tp.result.get_c_name(funcdecl))
+        prnt('{')
+        #
+        if not isinstance(tp.result, model.VoidType):
+            result_code = 'return '
+        else:
+            result_code = ''
+        prnt('  %s%s(%s);' % (result_code, name, ', '.join(argnames)))
+        prnt('}')
+        prnt()
+
+    _loading_gen_function = _loaded_noop
+
+    def _loaded_gen_function(self, tp, name, module, library):
+        assert isinstance(tp, model.FunctionPtrType)
+        if tp.ellipsis:
+            newfunction = self._load_constant(False, tp, name, module)
+        else:
+            indirections = []
+            if any(isinstance(type, model.StructOrUnion) for type in tp.args):
+                indirect_args = []
+                for i, type in enumerate(tp.args):
+                    if isinstance(type, model.StructOrUnion):
+                        type = model.PointerType(type)
+                        indirections.append((i, type))
+                    indirect_args.append(type)
+                tp = model.FunctionPtrType(tuple(indirect_args),
+                                           tp.result, tp.ellipsis)
+            BFunc = self.ffi._get_cached_btype(tp)
+            wrappername = '_cffi_f_%s' % name
+            newfunction = module.load_function(BFunc, wrappername)
+            for i, type in indirections:
+                newfunction = self._make_struct_wrapper(newfunction, i, type)
+        setattr(library, name, newfunction)
+
+    def _make_struct_wrapper(self, oldfunc, i, tp):
+        backend = self.ffi._backend
+        BType = self.ffi._get_cached_btype(tp)
+        def newfunc(*args):
+            args = args[:i] + (backend.newp(BType, args[i]),) + args[i+1:]
+            return oldfunc(*args)
+        return newfunc
+
+    # ----------
+    # named structs
+
+    def _generate_gen_struct_decl(self, tp, name):
+        assert name == tp.name
+        self._generate_struct_or_union_decl(tp, 'struct', name)
+
+    def _loading_gen_struct(self, tp, name, module):
+        self._loading_struct_or_union(tp, 'struct', name, module)
+
+    def _loaded_gen_struct(self, tp, name, module, **kwds):
+        self._loaded_struct_or_union(tp)
+
+    def _generate_struct_or_union_decl(self, tp, prefix, name):
+        if tp.fldnames is None:
+            return     # nothing to do with opaque structs
+        checkfuncname = '_cffi_check_%s_%s' % (prefix, name)
+        layoutfuncname = '_cffi_layout_%s_%s' % (prefix, name)
+        cname = ('%s %s' % (prefix, name)).strip()
+        #
+        prnt = self._prnt
+        prnt('static void %s(%s *p)' % (checkfuncname, cname))
+        prnt('{')
+        prnt('  /* only to generate compile-time warnings or errors */')
+        for i in range(len(tp.fldnames)):
+            fname = tp.fldnames[i]
+            ftype = tp.fldtypes[i]
+            if (isinstance(ftype, model.PrimitiveType)
+                and ftype.is_integer_type()):
+                # accept all integers, but complain on float or double
+                prnt('  (void)((p->%s) << 1);' % fname)
+            else:
+                # only accept exactly the type declared.  Note the parentheses
+                # around the '*tmp' below.  In most cases they are not needed
+                # but don't hurt --- except test_struct_array_field.
+                prnt('  { %s = &p->%s; (void)tmp; }' % (
+                    ftype.get_c_name('(*tmp)'), fname))
+        prnt('}')
+        prnt('ssize_t %s(ssize_t i)' % (layoutfuncname,))
+        prnt('{')
+        prnt('  struct _cffi_aligncheck { char x; %s y; };' % cname)
+        if tp.partial:
+            prnt('  static ssize_t nums[] = {')
+            prnt('    1, sizeof(%s),' % cname)
+            prnt('    offsetof(struct _cffi_aligncheck, y),')
+            for fname in tp.fldnames:
+                prnt('    offsetof(%s, %s),' % (cname, fname))
+                prnt('    sizeof(((%s *)0)->%s),' % (cname, fname))
+            prnt('    -1')
+            prnt('  };')
+            prnt('  return nums[i];')
+        else:
+            ffi = self.ffi
+            BStruct = ffi._get_cached_btype(tp)
+            conditions = [
+                'sizeof(%s) != %d' % (cname, ffi.sizeof(BStruct)),
+                'offsetof(struct _cffi_aligncheck, y) != %d' % (
+                    ffi.alignof(BStruct),)]
+            for fname, ftype in zip(tp.fldnames, tp.fldtypes):
+                BField = ffi._get_cached_btype(ftype)
+                conditions += [
+                    'offsetof(%s, %s) != %d' % (
+                        cname, fname, ffi.offsetof(BStruct, fname)),
+                    'sizeof(((%s *)0)->%s) != %d' % (
+                        cname, fname, ffi.sizeof(BField))]
+            prnt('  if (%s ||' % conditions[0])
+            for i in range(1, len(conditions)-1):
+                prnt('      %s ||' % conditions[i])
+            prnt('      %s) {' % conditions[-1])
+            prnt('    return -1;')
+            prnt('  }')
+            prnt('  else {')
+            prnt('    return 0;')
+            prnt('  }')
+        prnt('  /* the next line is not executed, but compiled */')
+        prnt('  %s(0);' % (checkfuncname,))
+        prnt('}')
+        prnt()
+
+    def _loading_struct_or_union(self, tp, prefix, name, module):
+        if tp.fldnames is None:
+            return     # nothing to do with opaque structs
+        layoutfuncname = '_cffi_layout_%s_%s' % (prefix, name)
+        cname = ('%s %s' % (prefix, name)).strip()
+        #
+        BFunc = self.ffi.typeof("ssize_t(*)(ssize_t)")
+        function = module.load_function(BFunc, layoutfuncname)
+        layout = function(0)
+        if layout < 0:
+            raise ffiplatform.VerificationError(
+                "incompatible layout for %s" % cname)
+        elif layout == 0:
+            assert not tp.partial
+        else:
+            totalsize = function(1)
+            totalalignment = function(2)
+            fieldofs = []
+            fieldsize = []
+            num = 3
+            while True:
+                x = function(num)
+                if x < 0: break
+                fieldofs.append(x)
+                fieldsize.append(function(num+1))
+                num += 2
+            assert len(fieldofs) == len(fieldsize) == len(tp.fldnames)
+            tp.fixedlayout = fieldofs, fieldsize, totalsize, totalalignment
+
+    def _loaded_struct_or_union(self, tp):
+        if tp.fldnames is None:
+            return     # nothing to do with opaque structs
+        self.ffi._get_cached_btype(tp)   # force 'fixedlayout' to be considered
+
+    # ----------
+    # 'anonymous' declarations.  These are produced for anonymous structs
+    # or unions; the 'name' is obtained by a typedef.
+
+    def _generate_gen_anonymous_decl(self, tp, name):
+        self._generate_struct_or_union_decl(tp, '', name)
+
+    def _loading_gen_anonymous(self, tp, name, module):
+        self._loading_struct_or_union(tp, '', name, module)
+
+    def _loaded_gen_anonymous(self, tp, name, module, **kwds):
+        self._loaded_struct_or_union(tp)
+
+    # ----------
+    # constants, likely declared with '#define'
+
+    def _generate_gen_const(self, is_int, name, tp=None, category='const'):
+        prnt = self._prnt
+        funcname = '_cffi_%s_%s' % (category, name)
+        if is_int:
+            assert category == 'const'
+            prnt('int %s(long long *out_value)' % funcname)
+            prnt('{')
+            prnt('  *out_value = (long long)(%s);' % (name,))
+            prnt('  return (%s) <= 0;' % (name,))
+            prnt('}')
+        else:
+            assert tp is not None
+            prnt(tp.get_c_name(' %s(void)' % funcname),)
+            prnt('{')
+            if category == 'var':
+                ampersand = '&'
+            else:
+                ampersand = ''
+            prnt('  return (%s%s);' % (ampersand, name))
+            prnt('}')
+        prnt()
+
+    def _generate_gen_constant_decl(self, tp, name):
+        is_int = isinstance(tp, model.PrimitiveType) and tp.is_integer_type()
+        self._generate_gen_const(is_int, name, tp)
+
+    _loading_gen_constant = _loaded_noop
+
+    def _load_constant(self, is_int, tp, name, module):
+        funcname = '_cffi_const_%s' % name
+        if is_int:
+            BFunc = self.ffi.typeof("int(*)(long long*)")
+            function = module.load_function(BFunc, funcname)
+            p = self.ffi.new("long long*")
+            negative = function(p)
+            value = int(p[0])
+            if value < 0 and not negative:
+                value += (1 << (8*self.ffi.sizeof("long long")))
+        else:
+            BFunc = self.ffi.typeof(tp.get_c_name('(*)(void)'))
+            function = module.load_function(BFunc, funcname)
+            value = function()
+        return value
+
+    def _loaded_gen_constant(self, tp, name, module, library):
+        is_int = isinstance(tp, model.PrimitiveType) and tp.is_integer_type()
+        value = self._load_constant(is_int, tp, name, module)
+        setattr(library, name, value)
+
+    # ----------
+    # enums
+
+    def _generate_gen_enum_decl(self, tp, name):
+        if tp.partial:
+            for enumerator in tp.enumerators:
+                self._generate_gen_const(True, enumerator)
+            return
+        #
+        funcname = '_cffi_enum_%s' % name
+        prnt = self._prnt
+        prnt('int %s(char *out_error)' % funcname)
+        prnt('{')
+        for enumerator, enumvalue in zip(tp.enumerators, tp.enumvalues):
+            prnt('  if (%s != %d) {' % (enumerator, enumvalue))
+            prnt('    snprintf(out_error, 255, "in enum %s: '
+                             '%s has the real value %d, not %d",')
+            prnt('            "%s", "%s", (int)%s, %d);' % (
+                name, enumerator, enumerator, enumvalue))
+            prnt('    return -1;')
+            prnt('  }')
+        prnt('  return 0;')
+        prnt('}')
+        prnt()
+
+    _loading_gen_enum = _loaded_noop
+
+    def _loading_gen_enum(self, tp, name, module):
+        if tp.partial:
+            enumvalues = [self._load_constant(True, tp, enumerator, module)
+                          for enumerator in tp.enumerators]
+            tp.enumvalues = tuple(enumvalues)
+            tp.partial = False
+        else:
+            BFunc = self.ffi.typeof("int(*)(char*)")
+            funcname = '_cffi_enum_%s' % name
+            function = module.load_function(BFunc, funcname)
+            p = self.ffi.new("char[]", 256)
+            if function(p) < 0:
+                raise ffiplatform.VerificationError(self.ffi.string(p))
+
+    def _loaded_gen_enum(self, tp, name, module, library):
+        for enumerator, enumvalue in zip(tp.enumerators, tp.enumvalues):
+            setattr(library, enumerator, enumvalue)
+
+    # ----------
+    # macros: for now only for integers
+
+    def _generate_gen_macro_decl(self, tp, name):
+        assert tp == '...'
+        self._generate_gen_const(True, name)
+
+    _loading_gen_macro = _loaded_noop
+
+    def _loaded_gen_macro(self, tp, name, module, library):
+        value = self._load_constant(True, tp, name, module)
+        setattr(library, name, value)
+
+    # ----------
+    # global variables
+
+    def _generate_gen_variable_decl(self, tp, name):
+        if isinstance(tp, model.ArrayType):
+            tp_ptr = model.PointerType(tp.item)
+            self._generate_gen_const(False, name, tp_ptr)
+        else:
+            tp_ptr = model.PointerType(tp)
+            self._generate_gen_const(False, name, tp_ptr, category='var')
+
+    _loading_gen_variable = _loaded_noop
+
+    def _loaded_gen_variable(self, tp, name, module, library):
+        if isinstance(tp, model.ArrayType):   # int a[5] is "constant" in the
+                                              # sense that "a=..." is forbidden
+            tp_ptr = model.PointerType(tp.item)
+            value = self._load_constant(False, tp_ptr, name, module)
+            setattr(library, name, value)
+            return
+        # remove ptr=<cdata 'int *'> from the library instance, and replace
+        # it by a property on the class, which reads/writes into ptr[0].
+        funcname = '_cffi_var_%s' % name
+        BFunc = self.ffi.typeof(tp.get_c_name('*(*)(void)'))
+        function = module.load_function(BFunc, funcname)
+        ptr = function()
+        def getter(library):
+            return ptr[0]
+        def setter(library, value):
+            ptr[0] = value
+        setattr(library.__class__, name, property(getter, setter))
+
+cffimod_header = r'''
+#include <stdio.h>
+#include <stddef.h>
+#include <stdint.h>
+#include <stdarg.h>
+#include <errno.h>
+#include <sys/types.h>   /* XXX for ssize_t */
+'''
diff --git a/cffi/verifier.py b/cffi/verifier.py
index 322169b..00aa5f5 100644
--- a/cffi/verifier.py
+++ b/cffi/verifier.py
@@ -1,26 +1,25 @@
 import sys, os, binascii, imp, shutil
-from . import model, ffiplatform
 from . import __version__
+from . import ffiplatform
 
 
 class Verifier(object):
     _status = '?'
 
-    def __init__(self, ffi, preamble, **kwds):
-        import _cffi_backend
-        if ffi._backend is not _cffi_backend:
-            raise NotImplementedError(
-                "verify() is only available for the _cffi_backend")
-        #
+    def __init__(self, ffi, preamble, force_generic_engine=False, **kwds):
         self.ffi = ffi
         self.preamble = preamble
         self.kwds = kwds
+        vengine_class = _locate_engine_class(ffi, force_generic_engine)
+        self._vengine = vengine_class(self)
         #
-        key = '\x00'.join(['2', sys.version[:3], __version__, preamble] +
+        key = '\x00'.join(['1', sys.version[:3], __version__, preamble] +
                           ffi._cdefsources)
-        k1 = hex(binascii.crc32(key[0::2]) & 0xffffffff).lstrip('0').rstrip('L')
-        k2 = hex(binascii.crc32(key[1::2]) & 0xffffffff).lstrip('0').rstrip('L')
-        modulename = '_cffi_%s%s' % (k1, k2)
+        k1 = hex(binascii.crc32(key[0::2]) & 0xffffffff)
+        k1 = k1.lstrip('0x').rstrip('L')
+        k2 = hex(binascii.crc32(key[1::2]) & 0xffffffff)
+        k2 = k2.lstrip('0').rstrip('L')
+        modulename = '_cffi_%s%s%s' % (self._vengine._class_key, k1, k2)
         suffix = _get_so_suffix()
         self.sourcefilename = os.path.join(_TMPDIR, modulename + '.c')
         self.modulefilename = os.path.join(_TMPDIR, modulename + suffix)
@@ -71,7 +70,7 @@ class Verifier(object):
         return ffiplatform.get_extension(sourcename, modname, **self.kwds)
 
     def generates_python_module(self):
-        return False
+        return self._vengine._gen_python_module
 
     # ----------
 
@@ -84,36 +83,23 @@ class Verifier(object):
             if f is not None:
                 f.close()
             self.modulefilename = filename
+        self._vengine.collect_types()
         self._status = 'module'
 
-    def _prnt(self, what=''):
-        print >> self._f, what
-
     def _write_source(self, file=None):
         must_close = (file is None)
         if must_close:
             _ensure_dir(self.sourcefilename)
             file = open(self.sourcefilename, 'w')
-        self._f = file
+        self._vengine._f = file
         try:
-            self._write_source_to_f()
+            self._vengine.write_source_to_f()
         finally:
-            del self._f
+            del self._vengine._f
             if must_close:
                 file.close()
         self._status = 'source'
 
-    def _write_source_to_f(self):
-        prnt = self._prnt
-        # first paste some standard set of lines that are mostly '#include'
-        prnt(cffimod_header)
-        # then paste the C source given by the user, verbatim.
-        prnt(self.preamble)
-        #
-        # call generate_cpy_xxx_decl(), for every xxx found from
-        # ffi._parser._declarations.  This generates all the functions.
-        self._generate("decl")
-
     def _compile_module(self):
         # compile this C source
         tmpdir = os.path.dirname(self.sourcefilename)
@@ -128,411 +114,31 @@ class Verifier(object):
         self._status = 'module'
 
     def _load_library(self):
-        # XXX review all usages of 'self' here!
-        # import it with the CFFI backend
-        backend = self.ffi._backend
-        module = backend.load_library(self.modulefilename)
-        #
-        # call loading_cpy_struct() to get the struct layout inferred by
-        # the C compiler
-        self._load(module, 'loading')
-        #
-        # the C code will need the <ctype> objects.  Collect them in
-        # order in a list.
-        #revmapping = dict([(value, key)
-        #                   for (key, value) in self._typesdict.items()])
-        #lst = [revmapping[i] for i in range(len(revmapping))]
-        #lst = map(self.ffi._get_cached_btype, lst)
-        #
-        # build the FFILibrary class and instance and call _cffi_setup().
-        # this will set up some fields like '_cffi_types', and only then
-        # it will invoke the chained list of functions that will really
-        # build (notably) the constant objects, as <cdata> if they are
-        # pointers, and store them as attributes on the 'library' object.
-        class FFILibrary(object):
-            _cffi_module = module
-        library = FFILibrary()
-        #module._cffi_setup(lst, ffiplatform.VerificationError, library)
-        #
-        # finally, call the loaded_cpy_xxx() functions.  This will perform
-        # the final adjustments, like copying the Python->C wrapper
-        # functions from the module to the 'library' object, and setting
-        # up the FFILibrary class with properties for the global C variables.
-        self._load(module, 'loaded', library=library)
-        return library
-
-    def _generate(self, step_name):
-        for name, tp in self.ffi._parser._declarations.iteritems():
-            kind, realname = name.split(' ', 1)
-            try:
-                method = getattr(self, '_generate_cpy_%s_%s' % (kind,
-                                                                step_name))
-            except AttributeError:
-                raise ffiplatform.VerificationError(
-                    "not implemented in verify(): %r" % name)
-            method(tp, realname)
+        return self._vengine.load_library()
 
-    def _load(self, module, step_name, **kwds):
-        for name, tp in self.ffi._parser._declarations.iteritems():
-            kind, realname = name.split(' ', 1)
-            method = getattr(self, '_%s_cpy_%s' % (step_name, kind))
-            method(tp, realname, module, **kwds)
-
-    def _generate_nothing(self, tp, name):
-        pass
-
-    def _loaded_noop(self, tp, name, module, **kwds):
-        pass
-
-    # ----------
-    # typedefs: generates no code so far
-
-    _generate_cpy_typedef_decl   = _generate_nothing
-    _loading_cpy_typedef         = _loaded_noop
-    _loaded_cpy_typedef          = _loaded_noop
-
-    # ----------
-    # function declarations
-
-    def _generate_cpy_function_decl(self, tp, name):
-        assert isinstance(tp, model.FunctionPtrType)
-        if tp.ellipsis:
-            # cannot support vararg functions better than this: check for its
-            # exact type (including the fixed arguments), and build it as a
-            # constant function pointer (no _cffi_f_%s wrapper)
-            self._generate_cpy_const(False, name, tp)
-            return
-        prnt = self._prnt
-        numargs = len(tp.args)
-        argnames = []
-        for i, type in enumerate(tp.args):
-            indirection = ''
-            if isinstance(type, model.StructOrUnion):
-                indirection = '*'
-            argnames.append('%sx%d' % (indirection, i))
-        arglist = [type.get_c_name(' %s' % arg)
-                   for type, arg in zip(tp.args, argnames)]
-        arglist = ', '.join(arglist) or 'void'
-        funcdecl = ' _cffi_f_%s(%s)' % (name, arglist)
-        prnt(tp.result.get_c_name(funcdecl))
-        prnt('{')
-        #
-        if not isinstance(tp.result, model.VoidType):
-            result_code = 'return '
-        else:
-            result_code = ''
-        prnt('  %s%s(%s);' % (result_code, name, ', '.join(argnames)))
-        prnt('}')
-        prnt()
-
-    _loading_cpy_function = _loaded_noop
-
-    def _loaded_cpy_function(self, tp, name, module, library):
-        assert isinstance(tp, model.FunctionPtrType)
-        if tp.ellipsis:
-            newfunction = self._load_constant(False, tp, name, module)
-        else:
-            indirections = []
-            if any(isinstance(type, model.StructOrUnion) for type in tp.args):
-                indirect_args = []
-                for i, type in enumerate(tp.args):
-                    if isinstance(type, model.StructOrUnion):
-                        type = model.PointerType(type)
-                        indirections.append((i, type))
-                    indirect_args.append(type)
-                tp = model.FunctionPtrType(tuple(indirect_args),
-                                           tp.result, tp.ellipsis)
-            BFunc = self.ffi._get_cached_btype(tp)
-            wrappername = '_cffi_f_%s' % name
-            newfunction = module.load_function(BFunc, wrappername)
-            for i, type in indirections:
-                newfunction = self._make_struct_wrapper(newfunction, i, type)
-        setattr(library, name, newfunction)
-
-    def _make_struct_wrapper(self, oldfunc, i, tp):
-        backend = self.ffi._backend
-        BType = self.ffi._get_cached_btype(tp)
-        def newfunc(*args):
-            args = args[:i] + (backend.newp(BType, args[i]),) + args[i+1:]
-            return oldfunc(*args)
-        return newfunc
-
-    # ----------
-    # named structs
-
-    def _generate_cpy_struct_decl(self, tp, name):
-        assert name == tp.name
-        self._generate_struct_or_union_decl(tp, 'struct', name)
-
-    def _loading_cpy_struct(self, tp, name, module):
-        self._loading_struct_or_union(tp, 'struct', name, module)
-
-    def _loaded_cpy_struct(self, tp, name, module, **kwds):
-        self._loaded_struct_or_union(tp)
-
-    def _generate_struct_or_union_decl(self, tp, prefix, name):
-        if tp.fldnames is None:
-            return     # nothing to do with opaque structs
-        checkfuncname = '_cffi_check_%s_%s' % (prefix, name)
-        layoutfuncname = '_cffi_layout_%s_%s' % (prefix, name)
-        cname = ('%s %s' % (prefix, name)).strip()
-        #
-        prnt = self._prnt
-        prnt('static void %s(%s *p)' % (checkfuncname, cname))
-        prnt('{')
-        prnt('  /* only to generate compile-time warnings or errors */')
-        for i in range(len(tp.fldnames)):
-            fname = tp.fldnames[i]
-            ftype = tp.fldtypes[i]
-            if (isinstance(ftype, model.PrimitiveType)
-                and ftype.is_integer_type()):
-                # accept all integers, but complain on float or double
-                prnt('  (void)((p->%s) << 1);' % fname)
-            else:
-                # only accept exactly the type declared.  Note the parentheses
-                # around the '*tmp' below.  In most cases they are not needed
-                # but don't hurt --- except test_struct_array_field.
-                prnt('  { %s = &p->%s; (void)tmp; }' % (
-                    ftype.get_c_name('(*tmp)'), fname))
-        prnt('}')
-        prnt('ssize_t %s(ssize_t i)' % (layoutfuncname,))
-        prnt('{')
-        prnt('  struct _cffi_aligncheck { char x; %s y; };' % cname)
-        if tp.partial:
-            prnt('  static ssize_t nums[] = {')
-            prnt('    1, sizeof(%s),' % cname)
-            prnt('    offsetof(struct _cffi_aligncheck, y),')
-            for fname in tp.fldnames:
-                prnt('    offsetof(%s, %s),' % (cname, fname))
-                prnt('    sizeof(((%s *)0)->%s),' % (cname, fname))
-            prnt('    -1')
-            prnt('  };')
-            prnt('  return nums[i];')
-        else:
-            ffi = self.ffi
-            BStruct = ffi._get_cached_btype(tp)
-            conditions = [
-                'sizeof(%s) != %d' % (cname, ffi.sizeof(BStruct)),
-                'offsetof(struct _cffi_aligncheck, y) != %d' % (
-                    ffi.alignof(BStruct),)]
-            for fname, ftype in zip(tp.fldnames, tp.fldtypes):
-                BField = ffi._get_cached_btype(ftype)
-                conditions += [
-                    'offsetof(%s, %s) != %d' % (
-                        cname, fname, ffi.offsetof(BStruct, fname)),
-                    'sizeof(((%s *)0)->%s) != %d' % (
-                        cname, fname, ffi.sizeof(BField))]
-            prnt('  if (%s ||' % conditions[0])
-            for i in range(1, len(conditions)-1):
-                prnt('      %s ||' % conditions[i])
-            prnt('      %s) {' % conditions[-1])
-            prnt('    return -1;')
-            prnt('  }')
-            prnt('  else {')
-            prnt('    return 0;')
-            prnt('  }')
-        prnt('  /* the next line is not executed, but compiled */')
-        prnt('  %s(0);' % (checkfuncname,))
-        prnt('}')
-        prnt()
-
-    def _loading_struct_or_union(self, tp, prefix, name, module):
-        if tp.fldnames is None:
-            return     # nothing to do with opaque structs
-        layoutfuncname = '_cffi_layout_%s_%s' % (prefix, name)
-        cname = ('%s %s' % (prefix, name)).strip()
-        #
-        BFunc = self.ffi.typeof("ssize_t(*)(ssize_t)")
-        function = module.load_function(BFunc, layoutfuncname)
-        layout = function(0)
-        if layout < 0:
-            raise ffiplatform.VerificationError(
-                "incompatible layout for %s" % cname)
-        elif layout == 0:
-            assert not tp.partial
-        else:
-            totalsize = function(1)
-            totalalignment = function(2)
-            fieldofs = []
-            fieldsize = []
-            num = 3
-            while True:
-                x = function(num)
-                if x < 0: break
-                fieldofs.append(x)
-                fieldsize.append(function(num+1))
-                num += 2
-            assert len(fieldofs) == len(fieldsize) == len(tp.fldnames)
-            tp.fixedlayout = fieldofs, fieldsize, totalsize, totalalignment
-
-    def _loaded_struct_or_union(self, tp):
-        if tp.fldnames is None:
-            return     # nothing to do with opaque structs
-        self.ffi._get_cached_btype(tp)   # force 'fixedlayout' to be considered
-
-    # ----------
-    # 'anonymous' declarations.  These are produced for anonymous structs
-    # or unions; the 'name' is obtained by a typedef.
-
-    def _generate_cpy_anonymous_decl(self, tp, name):
-        self._generate_struct_or_union_decl(tp, '', name)
-
-    def _loading_cpy_anonymous(self, tp, name, module):
-        self._loading_struct_or_union(tp, '', name, module)
-
-    def _loaded_cpy_anonymous(self, tp, name, module, **kwds):
-        self._loaded_struct_or_union(tp)
-
-    # ----------
-    # constants, likely declared with '#define'
-
-    def _generate_cpy_const(self, is_int, name, tp=None, category='const'):
-        prnt = self._prnt
-        funcname = '_cffi_%s_%s' % (category, name)
-        if is_int:
-            assert category == 'const'
-            prnt('int %s(long long *out_value)' % funcname)
-            prnt('{')
-            prnt('  *out_value = (long long)(%s);' % (name,))
-            prnt('  return (%s) <= 0;' % (name,))
-            prnt('}')
-        else:
-            assert tp is not None
-            prnt(tp.get_c_name(' %s(void)' % funcname),)
-            prnt('{')
-            if category == 'var':
-                ampersand = '&'
-            else:
-                ampersand = ''
-            prnt('  return (%s%s);' % (ampersand, name))
-            prnt('}')
-        prnt()
-
-    def _generate_cpy_constant_decl(self, tp, name):
-        is_int = isinstance(tp, model.PrimitiveType) and tp.is_integer_type()
-        self._generate_cpy_const(is_int, name, tp)
-
-    _loading_cpy_constant = _loaded_noop
-
-    def _load_constant(self, is_int, tp, name, module):
-        funcname = '_cffi_const_%s' % name
-        if is_int:
-            BFunc = self.ffi.typeof("int(*)(long long*)")
-            function = module.load_function(BFunc, funcname)
-            p = self.ffi.new("long long*")
-            negative = function(p)
-            value = int(p[0])
-            if value < 0 and not negative:
-                value += (1 << (8*self.ffi.sizeof("long long")))
-        else:
-            BFunc = self.ffi.typeof(tp.get_c_name('(*)(void)'))
-            function = module.load_function(BFunc, funcname)
-            value = function()
-        return value
-
-    def _loaded_cpy_constant(self, tp, name, module, library):
-        is_int = isinstance(tp, model.PrimitiveType) and tp.is_integer_type()
-        value = self._load_constant(is_int, tp, name, module)
-        setattr(library, name, value)
-
-    # ----------
-    # enums
-
-    def _generate_cpy_enum_decl(self, tp, name):
-        if tp.partial:
-            for enumerator in tp.enumerators:
-                self._generate_cpy_const(True, enumerator)
-            return
-        #
-        funcname = '_cffi_enum_%s' % name
-        prnt = self._prnt
-        prnt('int %s(char *out_error)' % funcname)
-        prnt('{')
-        for enumerator, enumvalue in zip(tp.enumerators, tp.enumvalues):
-            prnt('  if (%s != %d) {' % (enumerator, enumvalue))
-            prnt('    snprintf(out_error, 255, "in enum %s: '
-                             '%s has the real value %d, not %d",')
-            prnt('            "%s", "%s", (int)%s, %d);' % (
-                name, enumerator, enumerator, enumvalue))
-            prnt('    return -1;')
-            prnt('  }')
-        prnt('  return 0;')
-        prnt('}')
-        prnt()
-
-    _loading_cpy_enum = _loaded_noop
-
-    def _loading_cpy_enum(self, tp, name, module):
-        if tp.partial:
-            enumvalues = [self._load_constant(True, tp, enumerator, module)
-                          for enumerator in tp.enumerators]
-            tp.enumvalues = tuple(enumvalues)
-            tp.partial = False
-        else:
-            BFunc = self.ffi.typeof("int(*)(char*)")
-            funcname = '_cffi_enum_%s' % name
-            function = module.load_function(BFunc, funcname)
-            p = self.ffi.new("char[]", 256)
-            if function(p) < 0:
-                raise ffiplatform.VerificationError(self.ffi.string(p))
-
-    def _loaded_cpy_enum(self, tp, name, module, library):
-        for enumerator, enumvalue in zip(tp.enumerators, tp.enumvalues):
-            setattr(library, enumerator, enumvalue)
-
-    # ----------
-    # macros: for now only for integers
-
-    def _generate_cpy_macro_decl(self, tp, name):
-        assert tp == '...'
-        self._generate_cpy_const(True, name)
-
-    _loading_cpy_macro = _loaded_noop
-
-    def _loaded_cpy_macro(self, tp, name, module, library):
-        value = self._load_constant(True, tp, name, module)
-        setattr(library, name, value)
+# ____________________________________________________________
 
-    # ----------
-    # global variables
+_FORCE_GENERIC_ENGINE = False      # for tests
 
-    def _generate_cpy_variable_decl(self, tp, name):
-        if isinstance(tp, model.ArrayType):
-            tp_ptr = model.PointerType(tp.item)
-            self._generate_cpy_const(False, name, tp_ptr)
+def _locate_engine_class(ffi, force_generic_engine):
+    if _FORCE_GENERIC_ENGINE:
+        force_generic_engine = True
+    if not force_generic_engine:
+        if '__pypy__' in sys.builtin_module_names:
+            force_generic_engine = True
         else:
-            tp_ptr = model.PointerType(tp)
-            self._generate_cpy_const(False, name, tp_ptr, category='var')
-
-    _loading_cpy_variable = _loaded_noop
-
-    def _loaded_cpy_variable(self, tp, name, module, library):
-        if isinstance(tp, model.ArrayType):   # int a[5] is "constant" in the
-                                              # sense that "a=..." is forbidden
-            tp_ptr = model.PointerType(tp.item)
-            value = self._load_constant(False, tp_ptr, name, module)
-            setattr(library, name, value)
-            return
-        # remove ptr=<cdata 'int *'> from the library instance, and replace
-        # it by a property on the class, which reads/writes into ptr[0].
-        funcname = '_cffi_var_%s' % name
-        BFunc = self.ffi.typeof(tp.get_c_name('*(*)(void)'))
-        function = module.load_function(BFunc, funcname)
-        ptr = function()
-        def getter(library):
-            return ptr[0]
-        def setter(library, value):
-            ptr[0] = value
-        setattr(library.__class__, name, property(getter, setter))
-
-cffimod_header = r'''
-#include <stdio.h>
-#include <stddef.h>
-#include <stdint.h>
-#include <stdarg.h>
-#include <errno.h>
-#include <sys/types.h>   /* XXX for ssize_t */
-'''
+            try:
+                import _cffi_backend
+            except ImportError:
+                _cffi_backend = '?'
+            if ffi._backend is not _cffi_backend:
+                force_generic_engine = True
+    if force_generic_engine:
+        from . import vengine_gen
+        return vengine_gen.VGenericEngine
+    else:
+        from . import vengine_cpy
+        return vengine_cpy.VCPythonEngine
 
 # ____________________________________________________________
 
diff --git a/testing/test_verify.py b/testing/test_verify.py
index e9f5d74..13e7192 100644
--- a/testing/test_verify.py
+++ b/testing/test_verify.py
@@ -15,6 +15,19 @@ def setup_module():
     cffi.verifier.cleanup_tmpdir()
 
 
+def test_module_type():
+    import cffi.verifier
+    ffi = FFI()
+    lib = ffi.verify()
+    if hasattr(lib, '_cffi_python_module'):
+        print 'verify got a PYTHON module'
+    if hasattr(lib, '_cffi_generic_module'):
+        print 'verify got a GENERIC module'
+    expected_generic = (cffi.verifier._FORCE_GENERIC_ENGINE or
+                        '__pypy__' in sys.builtin_module_names)
+    assert hasattr(lib, '_cffi_python_module') == (not expected_generic)
+    assert hasattr(lib, '_cffi_generic_module') == expected_generic
+
 def test_missing_function():
     ffi = FFI()
     ffi.cdef("void some_completely_unknown_function();")
@@ -474,11 +487,14 @@ def test_access_callback():
     lib.cb = my_callback
     assert lib.foo(4) == 887
 
-def test_cannot_verify_with_ctypes():
+def test_ctypes_backend_forces_generic_engine():
     from cffi.backend_ctypes import CTypesBackend
     ffi = FFI(backend=CTypesBackend())
-    ffi.cdef("int a;")
-    py.test.raises(NotImplementedError, ffi.verify, "int a;")
+    ffi.cdef("int func(int a);")
+    lib = ffi.verify("int func(int a) { return a * 42; }")
+    assert not hasattr(lib, '_cffi_python_module')
+    assert hasattr(lib, '_cffi_generic_module')
+    assert lib.func(100) == 4200
 
 def test_call_with_struct_ptr():
     ffi = FFI()
diff --git a/testing/test_vgen.py b/testing/test_vgen.py
new file mode 100644
index 0000000..1a7e05d
--- /dev/null
+++ b/testing/test_vgen.py
@@ -0,0 +1,12 @@
+import cffi.verifier
+from .test_verify import *
+
+
+def setup_module():
+    cffi.verifier.cleanup_tmpdir()
+    cffi.verifier._FORCE_GENERIC_ENGINE = True
+    # Runs all tests with _FORCE_GENERIC_ENGINE = True, to make sure we
+    # also test vengine_gen.py.
+
+def teardown_module():
+    cffi.verifier._FORCE_GENERIC_ENGINE = False
diff --git a/testing/test_vgen2.py b/testing/test_vgen2.py
new file mode 100644
index 0000000..34147c8
--- /dev/null
+++ b/testing/test_vgen2.py
@@ -0,0 +1,13 @@
+import cffi.verifier
+from .test_vgen import *
+
+# This test file runs normally after test_vgen.  We only clean up the .c
+# sources, to check that it also works when we have only the .so.  The
+# tests should run much faster than test_vgen.
+
+def setup_module():
+    cffi.verifier.cleanup_tmpdir(keep_so=True)
+    cffi.verifier._FORCE_GENERIC_ENGINE = True
+
+def teardown_module():
+    cffi.verifier._FORCE_GENERIC_ENGINE = False
diff --git a/testing/test_zdistutils.py b/testing/test_zdistutils.py
index 7272ab5..92b5dd8 100644
--- a/testing/test_zdistutils.py
+++ b/testing/test_zdistutils.py
@@ -1,134 +1,159 @@
-import os, imp, math, StringIO, random
+import sys, os, imp, math, StringIO, random
 import py
 from cffi import FFI, FFIError
-from cffi.verifier import Verifier
+from cffi.verifier import Verifier, _locate_engine_class
 from testing.udir import udir
 
 
-def test_write_source():
-    ffi = FFI()
-    ffi.cdef("double sin(double x);")
-    csrc = '/*hi there!*/\n#include <math.h>\n'
-    v = Verifier(ffi, csrc)
-    v.write_source()
-    with file(v.sourcefilename, 'r') as f:
-        data = f.read()
-    assert csrc in data
-
-def test_write_source_explicit_filename():
-    ffi = FFI()
-    ffi.cdef("double sin(double x);")
-    csrc = '/*hi there!*/\n#include <math.h>\n'
-    v = Verifier(ffi, csrc)
-    v.sourcefilename = filename = str(udir.join('write_source.c'))
-    v.write_source()
-    assert filename == v.sourcefilename
-    with file(filename, 'r') as f:
-        data = f.read()
-    assert csrc in data
-
-def test_write_source_to_file_obj():
-    ffi = FFI()
-    ffi.cdef("double sin(double x);")
-    csrc = '/*hi there!*/\n#include <math.h>\n'
-    v = Verifier(ffi, csrc)
-    f = StringIO.StringIO()
-    v.write_source(file=f)
-    assert csrc in f.getvalue()
-
-def test_compile_module():
-    ffi = FFI()
-    ffi.cdef("double sin(double x);")
-    csrc = '/*hi there!*/\n#include <math.h>\n'
-    v = Verifier(ffi, csrc)
-    v.compile_module()
-    assert v.get_module_name().startswith('_cffi_')
-    if v.generates_python_module():
-        mod = imp.load_dynamic(v.get_module_name(), v.modulefilename)
-        assert hasattr(mod, '_cffi_setup')
-
-def test_compile_module_explicit_filename():
-    ffi = FFI()
-    ffi.cdef("double sin(double x);")
-    csrc = '/*hi there!2*/\n#include <math.h>\n'
-    v = Verifier(ffi, csrc)
-    v.modulefilename = filename = str(udir.join('test_compile_module.so'))
-    v.compile_module()
-    assert filename == v.modulefilename
-    assert v.get_module_name() == 'test_compile_module'
-    if v.generates_python_module():
-        mod = imp.load_dynamic(v.get_module_name(), v.modulefilename)
-        assert hasattr(mod, '_cffi_setup')
-
-def test_name_from_checksum_of_cdef():
-    names = []
-    for csrc in ['double', 'double', 'float']:
+class DistUtilsTest(object):
+
+    def test_locate_engine_class(self):
+        cls = _locate_engine_class(FFI(), self.generic)
+        if self.generic:
+            # asked for the generic engine, which must not generate a
+            # CPython extension module
+            assert not cls._gen_python_module
+        else:
+            # asked for the CPython engine: check that we got it, unless
+            # we are running on top of PyPy, where the generic engine is
+            # always better
+            if '__pypy__' not in sys.builtin_module_names:
+                assert cls._gen_python_module
+
+    def test_write_source(self):
         ffi = FFI()
-        ffi.cdef("%s sin(double x);" % csrc)
-        v = Verifier(ffi, "#include <math.h>")
-        names.append(v.get_module_name())
-    assert names[0] == names[1] != names[2]
-
-def test_name_from_checksum_of_csrc():
-    names = []
-    for csrc in ['123', '123', '1234']:
+        ffi.cdef("double sin(double x);")
+        csrc = '/*hi there!*/\n#include <math.h>\n'
+        v = Verifier(ffi, csrc, force_generic_engine=self.generic)
+        v.write_source()
+        with file(v.sourcefilename, 'r') as f:
+            data = f.read()
+        assert csrc in data
+
+    def test_write_source_explicit_filename(self):
         ffi = FFI()
         ffi.cdef("double sin(double x);")
-        v = Verifier(ffi, csrc)
-        names.append(v.get_module_name())
-    assert names[0] == names[1] != names[2]
-
-def test_load_library():
-    ffi = FFI()
-    ffi.cdef("double sin(double x);")
-    csrc = '/*hi there!3*/\n#include <math.h>\n'
-    v = Verifier(ffi, csrc)
-    library = v.load_library()
-    assert library.sin(12.3) == math.sin(12.3)
-
-def test_verifier_args():
-    ffi = FFI()
-    ffi.cdef("double sin(double x);")
-    csrc = '/*hi there!4*/#include "test_verifier_args.h"\n'
-    udir.join('test_verifier_args.h').write('#include <math.h>\n')
-    v = Verifier(ffi, csrc, include_dirs=[str(udir)])
-    library = v.load_library()
-    assert library.sin(12.3) == math.sin(12.3)
-
-def test_verifier_object_from_ffi():
-    ffi = FFI()
-    ffi.cdef("double sin(double x);")
-    csrc = "/*6*/\n#include <math.h>"
-    lib = ffi.verify(csrc)
-    assert lib.sin(12.3) == math.sin(12.3)
-    assert isinstance(ffi.verifier, Verifier)
-    with file(ffi.verifier.sourcefilename, 'r') as f:
-        data = f.read()
-    assert csrc in data
-
-def test_extension_object():
-    ffi = FFI()
-    ffi.cdef("double sin(double x);")
-    csrc = '''/*7*/
-#include <math.h>
-#ifndef TEST_EXTENSION_OBJECT
-# error "define_macros missing"
-#endif
-'''
-    lib = ffi.verify(csrc, define_macros=[('TEST_EXTENSION_OBJECT', '1')])
-    assert lib.sin(12.3) == math.sin(12.3)
-    v = ffi.verifier
-    ext = v.get_extension()
-    assert str(ext.__class__) == 'distutils.extension.Extension'
-    assert ext.sources == [v.sourcefilename]
-    assert ext.name == v.get_module_name()
-    assert ext.define_macros == [('TEST_EXTENSION_OBJECT', '1')]
-
-def test_extension_forces_write_source():
-    ffi = FFI()
-    ffi.cdef("double sin(double x);")
-    csrc = '/*hi there!%r*/\n#include <math.h>\n' % random.random()
-    v = Verifier(ffi, csrc)
-    assert not os.path.exists(v.sourcefilename)
-    v.get_extension()
-    assert os.path.exists(v.sourcefilename)
+        csrc = '/*hi there!*/\n#include <math.h>\n'
+        v = Verifier(ffi, csrc, force_generic_engine=self.generic)
+        v.sourcefilename = filename = str(udir.join('write_source.c'))
+        v.write_source()
+        assert filename == v.sourcefilename
+        with file(filename, 'r') as f:
+            data = f.read()
+        assert csrc in data
+
+    def test_write_source_to_file_obj(self):
+        ffi = FFI()
+        ffi.cdef("double sin(double x);")
+        csrc = '/*hi there!*/\n#include <math.h>\n'
+        v = Verifier(ffi, csrc, force_generic_engine=self.generic)
+        f = StringIO.StringIO()
+        v.write_source(file=f)
+        assert csrc in f.getvalue()
+
+    def test_compile_module(self):
+        ffi = FFI()
+        ffi.cdef("double sin(double x);")
+        csrc = '/*hi there!*/\n#include <math.h>\n'
+        v = Verifier(ffi, csrc, force_generic_engine=self.generic)
+        v.compile_module()
+        assert v.get_module_name().startswith('_cffi_')
+        if v.generates_python_module():
+            mod = imp.load_dynamic(v.get_module_name(), v.modulefilename)
+            assert hasattr(mod, '_cffi_setup')
+
+    def test_compile_module_explicit_filename(self):
+        ffi = FFI()
+        ffi.cdef("double sin(double x);")
+        csrc = '/*hi there!2*/\n#include <math.h>\n'
+        v = Verifier(ffi, csrc, force_generic_engine=self.generic)
+        v.modulefilename = filename = str(udir.join('test_compile_module.so'))
+        v.compile_module()
+        assert filename == v.modulefilename
+        assert v.get_module_name() == 'test_compile_module'
+        if v.generates_python_module():
+            mod = imp.load_dynamic(v.get_module_name(), v.modulefilename)
+            assert hasattr(mod, '_cffi_setup')
+
+    def test_name_from_checksum_of_cdef(self):
+        names = []
+        for csrc in ['double', 'double', 'float']:
+            ffi = FFI()
+            ffi.cdef("%s sin(double x);" % csrc)
+            v = Verifier(ffi, "#include <math.h>",
+                         force_generic_engine=self.generic)
+            names.append(v.get_module_name())
+        assert names[0] == names[1] != names[2]
+
+    def test_name_from_checksum_of_csrc(self):
+        names = []
+        for csrc in ['123', '123', '1234']:
+            ffi = FFI()
+            ffi.cdef("double sin(double x);")
+            v = Verifier(ffi, csrc, force_generic_engine=self.generic)
+            names.append(v.get_module_name())
+        assert names[0] == names[1] != names[2]
+
+    def test_load_library(self):
+        ffi = FFI()
+        ffi.cdef("double sin(double x);")
+        csrc = '/*hi there!3*/\n#include <math.h>\n'
+        v = Verifier(ffi, csrc, force_generic_engine=self.generic)
+        library = v.load_library()
+        assert library.sin(12.3) == math.sin(12.3)
+
+    def test_verifier_args(self):
+        ffi = FFI()
+        ffi.cdef("double sin(double x);")
+        csrc = '/*hi there!4*/#include "test_verifier_args.h"\n'
+        udir.join('test_verifier_args.h').write('#include <math.h>\n')
+        v = Verifier(ffi, csrc, include_dirs=[str(udir)],
+                     force_generic_engine=self.generic)
+        library = v.load_library()
+        assert library.sin(12.3) == math.sin(12.3)
+
+    def test_verifier_object_from_ffi(self):
+        ffi = FFI()
+        ffi.cdef("double sin(double x);")
+        csrc = "/*6*/\n#include <math.h>"
+        lib = ffi.verify(csrc, force_generic_engine=self.generic)
+        assert lib.sin(12.3) == math.sin(12.3)
+        assert isinstance(ffi.verifier, Verifier)
+        with file(ffi.verifier.sourcefilename, 'r') as f:
+            data = f.read()
+        assert csrc in data
+
+    def test_extension_object(self):
+        ffi = FFI()
+        ffi.cdef("double sin(double x);")
+        csrc = '''/*7*/
+    #include <math.h>
+    #ifndef TEST_EXTENSION_OBJECT
+    # error "define_macros missing"
+    #endif
+    '''
+        lib = ffi.verify(csrc, define_macros=[('TEST_EXTENSION_OBJECT', '1')],
+                         force_generic_engine=self.generic)
+        assert lib.sin(12.3) == math.sin(12.3)
+        v = ffi.verifier
+        ext = v.get_extension()
+        assert str(ext.__class__) == 'distutils.extension.Extension'
+        assert ext.sources == [v.sourcefilename]
+        assert ext.name == v.get_module_name()
+        assert ext.define_macros == [('TEST_EXTENSION_OBJECT', '1')]
+
+    def test_extension_forces_write_source(self):
+        ffi = FFI()
+        ffi.cdef("double sin(double x);")
+        csrc = '/*hi there!%r*/\n#include <math.h>\n' % random.random()
+        v = Verifier(ffi, csrc, force_generic_engine=self.generic)
+        assert not os.path.exists(v.sourcefilename)
+        v.get_extension()
+        assert os.path.exists(v.sourcefilename)
+
+
+class TestDistUtilsCPython(DistUtilsTest):
+    generic = False
+
+class TestDistUtilsGeneric(DistUtilsTest):
+    generic = True