mirror of https://github.com/python/cpython
266 lines
10 KiB
ReStructuredText
266 lines
10 KiB
ReStructuredText
.. highlight:: c
|
|
|
|
.. index:: object; code, code object
|
|
|
|
.. _codeobjects:
|
|
|
|
Code Objects
|
|
------------
|
|
|
|
.. sectionauthor:: Jeffrey Yasskin <jyasskin@gmail.com>
|
|
|
|
Code objects are a low-level detail of the CPython implementation.
|
|
Each one represents a chunk of executable code that hasn't yet been
|
|
bound into a function.
|
|
|
|
.. c:type:: PyCodeObject
|
|
|
|
The C structure of the objects used to describe code objects. The
|
|
fields of this type are subject to change at any time.
|
|
|
|
|
|
.. c:var:: PyTypeObject PyCode_Type
|
|
|
|
This is an instance of :c:type:`PyTypeObject` representing the Python
|
|
:ref:`code object <code-objects>`.
|
|
|
|
|
|
.. c:function:: int PyCode_Check(PyObject *co)
|
|
|
|
Return true if *co* is a :ref:`code object <code-objects>`.
|
|
This function always succeeds.
|
|
|
|
.. c:function:: int PyCode_GetNumFree(PyCodeObject *co)
|
|
|
|
Return the number of free variables in *co*.
|
|
|
|
.. c:function:: PyCodeObject* PyUnstable_Code_New(int argcount, int kwonlyargcount, int nlocals, int stacksize, int flags, PyObject *code, PyObject *consts, PyObject *names, PyObject *varnames, PyObject *freevars, PyObject *cellvars, PyObject *filename, PyObject *name, PyObject *qualname, int firstlineno, PyObject *linetable, PyObject *exceptiontable)
|
|
|
|
Return a new code object. If you need a dummy code object to create a frame,
|
|
use :c:func:`PyCode_NewEmpty` instead.
|
|
|
|
Since the definition of the bytecode changes often, calling
|
|
:c:func:`PyUnstable_Code_New` directly can bind you to a precise Python version.
|
|
|
|
The many arguments of this function are inter-dependent in complex
|
|
ways, meaning that subtle changes to values are likely to result in incorrect
|
|
execution or VM crashes. Use this function only with extreme care.
|
|
|
|
.. versionchanged:: 3.11
|
|
Added ``qualname`` and ``exceptiontable`` parameters.
|
|
|
|
.. index:: single: PyCode_New (C function)
|
|
|
|
.. versionchanged:: 3.12
|
|
|
|
Renamed from ``PyCode_New`` as part of :ref:`unstable-c-api`.
|
|
The old name is deprecated, but will remain available until the
|
|
signature changes again.
|
|
|
|
.. c:function:: PyCodeObject* PyUnstable_Code_NewWithPosOnlyArgs(int argcount, int posonlyargcount, int kwonlyargcount, int nlocals, int stacksize, int flags, PyObject *code, PyObject *consts, PyObject *names, PyObject *varnames, PyObject *freevars, PyObject *cellvars, PyObject *filename, PyObject *name, PyObject *qualname, int firstlineno, PyObject *linetable, PyObject *exceptiontable)
|
|
|
|
Similar to :c:func:`PyUnstable_Code_New`, but with an extra "posonlyargcount" for positional-only arguments.
|
|
The same caveats that apply to ``PyUnstable_Code_New`` also apply to this function.
|
|
|
|
.. index:: single: PyCode_NewWithPosOnlyArgs (C function)
|
|
|
|
.. versionadded:: 3.8 as ``PyCode_NewWithPosOnlyArgs``
|
|
|
|
.. versionchanged:: 3.11
|
|
Added ``qualname`` and ``exceptiontable`` parameters.
|
|
|
|
.. versionchanged:: 3.12
|
|
|
|
Renamed to ``PyUnstable_Code_NewWithPosOnlyArgs``.
|
|
The old name is deprecated, but will remain available until the
|
|
signature changes again.
|
|
|
|
.. c:function:: PyCodeObject* PyCode_NewEmpty(const char *filename, const char *funcname, int firstlineno)
|
|
|
|
Return a new empty code object with the specified filename,
|
|
function name, and first line number. The resulting code
|
|
object will raise an ``Exception`` if executed.
|
|
|
|
.. c:function:: int PyCode_Addr2Line(PyCodeObject *co, int byte_offset)
|
|
|
|
Return the line number of the instruction that occurs on or before ``byte_offset`` and ends after it.
|
|
If you just need the line number of a frame, use :c:func:`PyFrame_GetLineNumber` instead.
|
|
|
|
For efficiently iterating over the line numbers in a code object, use `the API described in PEP 626
|
|
<https://peps.python.org/pep-0626/#out-of-process-debuggers-and-profilers>`_.
|
|
|
|
.. c:function:: int PyCode_Addr2Location(PyObject *co, int byte_offset, int *start_line, int *start_column, int *end_line, int *end_column)
|
|
|
|
Sets the passed ``int`` pointers to the source code line and column numbers
|
|
for the instruction at ``byte_offset``. Sets the value to ``0`` when
|
|
information is not available for any particular element.
|
|
|
|
Returns ``1`` if the function succeeds and 0 otherwise.
|
|
|
|
.. versionadded:: 3.11
|
|
|
|
.. c:function:: PyObject* PyCode_GetCode(PyCodeObject *co)
|
|
|
|
Equivalent to the Python code ``getattr(co, 'co_code')``.
|
|
Returns a strong reference to a :c:type:`PyBytesObject` representing the
|
|
bytecode in a code object. On error, ``NULL`` is returned and an exception
|
|
is raised.
|
|
|
|
This ``PyBytesObject`` may be created on-demand by the interpreter and does
|
|
not necessarily represent the bytecode actually executed by CPython. The
|
|
primary use case for this function is debuggers and profilers.
|
|
|
|
.. versionadded:: 3.11
|
|
|
|
.. c:function:: PyObject* PyCode_GetVarnames(PyCodeObject *co)
|
|
|
|
Equivalent to the Python code ``getattr(co, 'co_varnames')``.
|
|
Returns a new reference to a :c:type:`PyTupleObject` containing the names of
|
|
the local variables. On error, ``NULL`` is returned and an exception
|
|
is raised.
|
|
|
|
.. versionadded:: 3.11
|
|
|
|
.. c:function:: PyObject* PyCode_GetCellvars(PyCodeObject *co)
|
|
|
|
Equivalent to the Python code ``getattr(co, 'co_cellvars')``.
|
|
Returns a new reference to a :c:type:`PyTupleObject` containing the names of
|
|
the local variables that are referenced by nested functions. On error, ``NULL``
|
|
is returned and an exception is raised.
|
|
|
|
.. versionadded:: 3.11
|
|
|
|
.. c:function:: PyObject* PyCode_GetFreevars(PyCodeObject *co)
|
|
|
|
Equivalent to the Python code ``getattr(co, 'co_freevars')``.
|
|
Returns a new reference to a :c:type:`PyTupleObject` containing the names of
|
|
the free variables. On error, ``NULL`` is returned and an exception is raised.
|
|
|
|
.. versionadded:: 3.11
|
|
|
|
.. c:function:: int PyCode_AddWatcher(PyCode_WatchCallback callback)
|
|
|
|
Register *callback* as a code object watcher for the current interpreter.
|
|
Return an ID which may be passed to :c:func:`PyCode_ClearWatcher`.
|
|
In case of error (e.g. no more watcher IDs available),
|
|
return ``-1`` and set an exception.
|
|
|
|
.. versionadded:: 3.12
|
|
|
|
.. c:function:: int PyCode_ClearWatcher(int watcher_id)
|
|
|
|
Clear watcher identified by *watcher_id* previously returned from
|
|
:c:func:`PyCode_AddWatcher` for the current interpreter.
|
|
Return ``0`` on success, or ``-1`` and set an exception on error
|
|
(e.g. if the given *watcher_id* was never registered.)
|
|
|
|
.. versionadded:: 3.12
|
|
|
|
.. c:type:: PyCodeEvent
|
|
|
|
Enumeration of possible code object watcher events:
|
|
- ``PY_CODE_EVENT_CREATE``
|
|
- ``PY_CODE_EVENT_DESTROY``
|
|
|
|
.. versionadded:: 3.12
|
|
|
|
.. c:type:: int (*PyCode_WatchCallback)(PyCodeEvent event, PyCodeObject* co)
|
|
|
|
Type of a code object watcher callback function.
|
|
|
|
If *event* is ``PY_CODE_EVENT_CREATE``, then the callback is invoked
|
|
after `co` has been fully initialized. Otherwise, the callback is invoked
|
|
before the destruction of *co* takes place, so the prior state of *co*
|
|
can be inspected.
|
|
|
|
If *event* is ``PY_CODE_EVENT_DESTROY``, taking a reference in the callback
|
|
to the about-to-be-destroyed code object will resurrect it and prevent it
|
|
from being freed at this time. When the resurrected object is destroyed
|
|
later, any watcher callbacks active at that time will be called again.
|
|
|
|
Users of this API should not rely on internal runtime implementation
|
|
details. Such details may include, but are not limited to, the exact
|
|
order and timing of creation and destruction of code objects. While
|
|
changes in these details may result in differences observable by watchers
|
|
(including whether a callback is invoked or not), it does not change
|
|
the semantics of the Python code being executed.
|
|
|
|
If the callback sets an exception, it must return ``-1``; this exception will
|
|
be printed as an unraisable exception using :c:func:`PyErr_WriteUnraisable`.
|
|
Otherwise it should return ``0``.
|
|
|
|
There may already be a pending exception set on entry to the callback. In
|
|
this case, the callback should return ``0`` with the same exception still
|
|
set. This means the callback may not call any other API that can set an
|
|
exception unless it saves and clears the exception state first, and restores
|
|
it before returning.
|
|
|
|
.. versionadded:: 3.12
|
|
|
|
|
|
Extra information
|
|
-----------------
|
|
|
|
To support low-level extensions to frame evaluation, such as external
|
|
just-in-time compilers, it is possible to attach arbitrary extra data to
|
|
code objects.
|
|
|
|
These functions are part of the unstable C API tier:
|
|
this functionality is a CPython implementation detail, and the API
|
|
may change without deprecation warnings.
|
|
|
|
.. c:function:: Py_ssize_t PyUnstable_Eval_RequestCodeExtraIndex(freefunc free)
|
|
|
|
Return a new an opaque index value used to adding data to code objects.
|
|
|
|
You generally call this function once (per interpreter) and use the result
|
|
with ``PyCode_GetExtra`` and ``PyCode_SetExtra`` to manipulate
|
|
data on individual code objects.
|
|
|
|
If *free* is not ``NULL``: when a code object is deallocated,
|
|
*free* will be called on non-``NULL`` data stored under the new index.
|
|
Use :c:func:`Py_DecRef` when storing :c:type:`PyObject`.
|
|
|
|
.. index:: single: _PyEval_RequestCodeExtraIndex (C function)
|
|
|
|
.. versionadded:: 3.6 as ``_PyEval_RequestCodeExtraIndex``
|
|
|
|
.. versionchanged:: 3.12
|
|
|
|
Renamed to ``PyUnstable_Eval_RequestCodeExtraIndex``.
|
|
The old private name is deprecated, but will be available until the API
|
|
changes.
|
|
|
|
.. c:function:: int PyUnstable_Code_GetExtra(PyObject *code, Py_ssize_t index, void **extra)
|
|
|
|
Set *extra* to the extra data stored under the given index.
|
|
Return 0 on success. Set an exception and return -1 on failure.
|
|
|
|
If no data was set under the index, set *extra* to ``NULL`` and return
|
|
0 without setting an exception.
|
|
|
|
.. index:: single: _PyCode_GetExtra (C function)
|
|
|
|
.. versionadded:: 3.6 as ``_PyCode_GetExtra``
|
|
|
|
.. versionchanged:: 3.12
|
|
|
|
Renamed to ``PyUnstable_Code_GetExtra``.
|
|
The old private name is deprecated, but will be available until the API
|
|
changes.
|
|
|
|
.. c:function:: int PyUnstable_Code_SetExtra(PyObject *code, Py_ssize_t index, void *extra)
|
|
|
|
Set the extra data stored under the given index to *extra*.
|
|
Return 0 on success. Set an exception and return -1 on failure.
|
|
|
|
.. index:: single: _PyCode_SetExtra (C function)
|
|
|
|
.. versionadded:: 3.6 as ``_PyCode_SetExtra``
|
|
|
|
.. versionchanged:: 3.12
|
|
|
|
Renamed to ``PyUnstable_Code_SetExtra``.
|
|
The old private name is deprecated, but will be available until the API
|
|
changes.
|