[pypy-dev] Fwd: Re: Adding init/variables to W_Root

[Frank Wang]

Hi Armin,

I've taken your advice, and my W_Root has these additions (in bold):

class W_Root(object):
    _attrs_ = ['__weakref__', *'rb_flags'*]
    _must_be_light_finalizer_ = True
    user_overridden_class = False
    # Riverbed flags
*    rb_flags = None*

*    def add_rbflags(self, new_flags):*
*        if self.rb_flags is None:*
*            self.rb_flags = {}*
*        for flag in new_flags:*
*            self.rb_flags[flag] = None*

*    def set_rbflags(self, new_flags):*
*        self.rb_flags = new_flags*

*    def get_rbflags(self):*
*        if self.rb_flags is None:*
*            self.rb_flags = {}*
*        return self.rb_flags*

In pyopcode.py, I've made the following modifications. I've shown them in
bold. The high level idea is that for a binary operation, I want to take
the union of the rb_flags in w_1 and w_2 and set the union to be the
rb_flags in w_result.

def binaryoperation(operationname):
    """NOT_RPYTHON"""
    def opimpl(self, *ignored):
        operation = getattr(self.space, operationname)
        w_2 = self.popvalue()
        w_1 = self.popvalue()
        w_result = operation(w_1, w_2)

        # union flags in w_1 and w_2 and propagate to result
*        w_1_rbflags = w_1.get_rbflags()*
*        w_2_rbflags = w_2.get_rbflags()*
*        w_1_rbflags.update(w_2_rbflags)*
*        w_result.set_rbflags(w_1_rbflags)*

        self.pushvalue(w_result)

    opimpl.binop = operationname

    return func_with_new_name(opimpl, "opcode_impl_for_%s" % operationname)

However, when I do this, I get the following error:

[translation:ERROR] UnionError:

Offending annotations:
  SomeOrderedDict(dictdef=<{SomeImpossibleValue(): SomeImpossibleValue()}>)
  SomeInstance(can_be_None=True,
classdef=pypy.interpreter.baseobjspace.W_Root)


    v945 = setattr(self_268, ('rb_flags'), v944)

In <FunctionGraph of (pypy.interpreter.baseobjspace:46)W_Root.get_rbflags
at 0x40f26de8>:
Happened at file
/home/ubuntu/pypy2-v5.3.1-src/pypy/interpreter/baseobjspace.py line 48

==>             self.rb_flags = {}

Known variable annotations:
 self_268 = SomeInstance(can_be_None=False,
classdef=pypy.interpreter.baseobjspace.W_Root)
 v944 = SomeOrderedDict(dictdef=<{SomeImpossibleValue():
SomeImpossibleValue()}>)

Processing block:
 block at 15 is a <class 'rpython.flowspace.flowcontext.SpamBlock'>
 in (pypy.interpreter.baseobjspace:46)W_Root.get_rbflags
 containing the following operations:
       v944 = newdict()
       v945 = setattr(self_268, ('rb_flags'), v944)
 --end--

Any thoughts on this?

Frank

On Mon, Dec 19, 2016 at 10:32 PM, Frank Wang <frankw at mit.edu> wrote:

> Hi Armin,
>
> It seems that with your suggestions, things have started to work!
>
> Thanks again for the help!
>
> On Mon, Dec 19, 2016 at 5:57 PM Armin Rigo <armin.rigo at gmail.com> wrote:
>
>> Hi Frank,
>>
>> On 20 December 2016 at 01:29, Frank Wang <frankw at mit.edu> wrote:
>> > This also seems to happen in a lot of classes because W_Root is the
>> parent
>> > class for many classes. Is there a way to universally turn off this
>> > immutable flag (assuming it's okay) in all classes?
>>
>> You can hack at the place where the error is raised.  Assuming you're
>> translating without the JIT, it should not cause too much problems.
>>
>> As an alternative to adding an attribute to every object, you could
>> also use a rpython.rlib.rweakref.RWeakKeyDictionary(W_Root, RbFlags),
>> for some class RbFlags which has got the rb_flags dictionary and/or
>> any other related data.  The advantage is that it is a less intrusive
>> change, reduces memory usage if many objects don't need the extra
>> information at all, and avoids the immutable problem.  The
>> inconvenient is that going from the object to the rb_flags dictionary
>> is slower.
>>
>> There are also alternatives that are better if you are ok with
>> supporting not *all* objects.  For example, you can edit
>> objspace/std/mapdict.py to add a new dynamic attribute that is
>> internally called ``"rbflags", SPECIAL``; see ``"weakref", SPECIAL``
>> for an existing example.  This would work for all objects that use
>> mapdicts, i.e. all instances of user-defined classes, and additionally
>> instances of many built-in types as well---but not instances of the
>> core types like "int" or "str" or "list" or "tuple" or "dict".
>>
>>
>> A bientôt,
>>
>> Armin.
>>
>
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