[pypy-dev] PyCodeObject incompatibility

[Dmitry Kovner]

Hi, again! First of all, thanks for the fast reply! The answer helped me a
lot. However, during the porting of the extension to the awesome PyPy, I've
got more questions:
1. The extension uses opcodes from cPython's opcode.h header file. (
https://github.com/python/cpython/blob/8a84aef0123bd8c13cf81fbc3b5f6d45f96c2656/Include/opcode.h)
There is no such file in the implementation of C API in PyPy. What could
you recommend as the best alternative?
2. The extension uses some fields of PyThreadState structure. For example,
its frame field (
https://github.com/python/cpython/blob/8a84aef0123bd8c13cf81fbc3b5f6d45f96c2656/Include/cpython/pystate.h#L59).
Is it right to use PyObject_GetAttrString() to access that field in PyPy C
API?
3. There is no function PyFrame_FastToLocals (
https://github.com/python/cpython/blob/8a84aef0123bd8c13cf81fbc3b5f6d45f96c2656/Objects/frameobject.c#L931)
in the C API of PyPy. Are there any alternatives?
4. Functions PyEval_SetTrace(), PyEval_SetProfile(),
PyFrame_GetLineNumber() are defined only in stubs.py in PyPy. (
https://foss.heptapod.net/pypy/pypy/-/blob/branch/py3.7/pypy/module/cpyext/stubs.py#L918)
Is there a way to get that information in PyPy except patching of its
source code?
5. Are there any analogues of all PyTrace_* constants (
https://github.com/python/cpython/blob/8a84aef0123bd8c13cf81fbc3b5f6d45f96c2656/Include/cpython/pystate.h#L26)
in the PyPy C API?
6. There is no function PyFrame_Check() (
https://github.com/python/cpython/blob/8a84aef0123bd8c13cf81fbc3b5f6d45f96c2656/Include/frameobject.h#L53)
in the PyPy C API. Are there any alternatives?

I'm really sorry for the long question! I hope the list of the problems
described above is full enough to port the extension and I will have no
more questions. :)

Best regards, Dmitrii

чт, 10 февр. 2022 г. в 23:07, Armin Rigo <armin.rigo at gmail.com>:

> Hi,
>
> On Thu, 10 Feb 2022 at 14:03, Dmitry Kovner <dmitryk at lightrun.com> wrote:
> > Hello! I'm trying to build a low-level C API extension of cPython to be
> used in PyPy. The extension extensively uses some fields of PyCodeObject (
> https://github.com/python/cpython/blob/f87e616af038ee8963185e11b96841c81e8ef15a/Include/code.h#L23):
> co_firstlineno, co_stacksize, co_consts and so on. However, it seems these
> fields are not defined in the similar structure of the PyPy
> implementation:
> https://foss.heptapod.net/pypy/pypy/-/blob/branch/py3.8/pypy/module/cpyext/include/code.h#L7.
> Is it possible to get values of these fields using PyPy C API somehow?
>
> Yes, it's a limitation of PyPy not to expose these fields.  If you
> want to write portable code that always works, the simplest is to call
> `PyObject_GetAttrString(code, "__consts__")` etc.  Remember that you
> need to call `Py_DECREF()` on the result at some point.
>
>
> A bientôt,
>
> Armin.
>
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