cpython/Include
Eric Snow 2c1e2583fd
bpo-43693: Add new internal code objects fields: co_fastlocalnames and co_fastlocalkinds. (gh-26388)
A number of places in the code base (notably ceval.c and frameobject.c) rely on mapping variable names to indices in the frame "locals plus" array (AKA fast locals), and thus opargs.  Currently the compiler indirectly encodes that information on the code object as the tuples co_varnames, co_cellvars, and co_freevars.  At runtime the dependent code must calculate the proper mapping from those, which isn't ideal and impacts performance-sensitive sections.  This is something we can easily address in the compiler instead.

This change addresses the situation by replacing internal use of co_varnames, etc. with a single combined tuple of names in locals-plus order, along with a minimal array mapping each to its kind (local vs. cell vs. free).  These two new PyCodeObject fields, co_fastlocalnames and co_fastllocalkinds, are not exposed to Python code for now, but co_varnames, etc. are still available with the same values as before (though computed lazily).

Aside from the (mild) performance impact, there are a number of other benefits:

* there's now a clear, direct relationship between locals-plus and variables
* code that relies on the locals-plus-to-name mapping is simpler
* marshaled code objects are smaller and serialize/de-serialize faster

Also note that we can take this approach further by expanding the possible values in co_fastlocalkinds to include specific argument types (e.g. positional-only, kwargs).  Doing so would allow further speed-ups in _PyEval_MakeFrameVector(), which is where args get unpacked into the locals-plus array.  It would also allow us to shrink marshaled code objects even further.

https://bugs.python.org/issue43693
2021-06-03 10:28:27 -06:00
..
cpython bpo-43693: Add new internal code objects fields: co_fastlocalnames and co_fastlocalkinds. (gh-26388) 2021-06-03 10:28:27 -06:00
internal bpo-43693: Add new internal code objects fields: co_fastlocalnames and co_fastlocalkinds. (gh-26388) 2021-06-03 10:28:27 -06:00
abstract.h bpo-31861: Add aiter and anext to builtins (#23847) 2021-03-23 15:47:21 -07:00
bltinmodule.h these builtins have to be initialized 2009-05-09 18:10:51 +00:00
boolobject.h bpo-43795: PEP-652: Simplify headers for easier static analysis (GH-25483) 2021-04-23 14:14:00 +02:00
bytearrayobject.h bpo-39573: Add Py_IS_TYPE() function (GH-18488) 2020-02-13 18:37:17 +01:00
bytesobject.h bpo-42431: Fix outdated bytes comments (GH-23458) 2020-12-03 12:46:16 +02:00
cellobject.h bpo-30459: Cast the result of PyCell_SET to void (GH-23654) 2020-12-07 11:56:20 +01:00
ceval.h bpo-41936. Remove macros Py_ALLOW_RECURSION/Py_END_ALLOW_RECURSION (GH-22552) 2020-10-05 12:32:00 +03:00
classobject.h bpo-39573: PyXXX_Check() macros use Py_IS_TYPE() (GH-18508) 2020-02-14 08:48:12 +01:00
code.h bpo-40421: Add Include/cpython/code.h header file (GH-19756) 2020-04-28 17:07:12 +02:00
codecs.h bpo-41842: Add codecs.unregister() function (GH-22360) 2020-09-28 23:41:11 +02:00
compile.h bpo-35134: Add include/cpython/compile.h (GH-24922) 2021-03-22 09:32:11 +01:00
complexobject.h bpo-39573: Add Py_IS_TYPE() function (GH-18488) 2020-02-13 18:37:17 +01:00
context.h bpo-40428: Remove PyTuple_ClearFreeList() function (GH-19769) 2020-04-29 02:29:20 +02:00
datetime.h bpo-30155: Add macros to get tzinfo from datetime instances (GH-21633) 2020-09-23 14:43:45 -04:00
descrobject.h bpo-40170: Convert PyDescr_IsData() to static inline function (GH-24535) 2021-02-16 08:50:00 +01:00
dictobject.h bpo-41845: Move PyObject_GenericGetDict() back into the limited API (GH22646) 2020-10-19 23:47:37 +01:00
dynamic_annotations.h fix instances of consecutive articles (closes #23221) 2015-01-13 09:17:24 -05:00
enumobject.h
errcode.h bpo-44201: Avoid side effects of "invalid_*" rules in the REPL (GH-26298) 2021-05-22 23:05:00 +01:00
eval.h bpo-42990: Further refactoring of PyEval_ functions. (GH-24368) 2021-02-01 10:42:03 +00:00
exports.h bpo-11410: Standardize and use symbol visibility attributes across POSIX and Windows. (GH-16347) 2019-10-15 08:26:12 +01:00
fileobject.h bpo-41986: Add Py_FileSystemDefaultEncodeErrors and Py_UTF8Mode back to limited API (GH-22621) 2020-10-10 17:09:45 +03:00
fileutils.h bpo-43795: PEP-652: Clean up the stable ABI/limited API (GH-25482) 2021-04-23 14:17:58 +02:00
floatobject.h bpo-40428: Remove PyTuple_ClearFreeList() function (GH-19769) 2020-04-29 02:29:20 +02:00
frameobject.h bpo-40421: Add pyframe.h header file (GH-19755) 2020-04-28 16:32:48 +02:00
funcobject.h bpo-42990: Introduce 'frame constructor' struct to simplify API for PyEval_CodeEval and friends (GH-24298) 2021-01-29 13:24:55 +00:00
genericaliasobject.h bpo-39481: Implementation for PEP 585 (#18239) 2020-04-07 09:50:06 -07:00
genobject.h bpo-44032: Move data stack to thread from FrameObject. (GH-26076) 2021-05-21 10:57:35 +01:00
import.h bpo-39372: Clean header files of declared interfaces with no implementations (GH-18037) 2020-01-18 03:14:59 +00:00
interpreteridobject.h bpo-36097: Use only public C-API in the_xxsubinterpreters module (adding as necessary). (gh-12359) 2019-03-15 16:35:46 -06:00
intrcheck.h bpo-41713: Remove PyOS_InitInterrupts() function (GH-23342) 2020-11-17 16:22:23 +01:00
iterobject.h bpo-43770: _PyTypes_Init() inits _PyAnextAwaitable_Type (GH-25266) 2021-04-08 09:58:15 +02:00
listobject.h bpo-39573: Add Py_IS_TYPE() function (GH-18488) 2020-02-13 18:37:17 +01:00
longintrepr.h bpo-32150: Expand tabs to spaces in C files. (#4583) 2017-11-28 17:56:10 +02:00
longobject.h bpo-42161: Remove private _PyLong_Zero and _PyLong_One (GH-23003) 2020-10-27 21:34:33 +01:00
marshal.h Issue #1772673: The type of char* arguments now changed to const char*. 2013-10-19 21:03:34 +03:00
memoryobject.h bpo-39573: Add Py_IS_TYPE() function (GH-18488) 2020-02-13 18:37:17 +01:00
methodobject.h bpo-43688: Fix Py_LIMITED_API version of xxlimited (GH-25135) 2021-04-01 15:09:33 +02:00
modsupport.h bpo-1635741: Add PyModule_AddObjectRef() function (GH-23122) 2020-11-04 13:59:15 +01:00
moduleobject.h bpo-42923: Dump extension modules on fatal error (GH-24207) 2021-01-18 20:47:13 +01:00
namespaceobject.h Issue #26900: Excluded underscored names and other private API from limited API. 2016-09-11 11:03:14 +03:00
object.h bpo-43916: Add Py_TPFLAGS_DISALLOW_INSTANTIATION type flag (GH-25721) 2021-04-30 12:46:15 +02:00
objimpl.h bpo-43774: Remove unused PYMALLOC_DEBUG macro (GH-25711) 2021-04-29 10:47:47 +02:00
opcode.h bpo-26110: Add `CALL_METHOD_KW` opcode to speedup method calls with keywords (GH-26014) 2021-05-15 16:15:23 +01:00
osdefs.h bpo-31904: Add cross-build support for VxWorks RTOS (GH-11968) 2019-02-27 12:09:28 +01:00
osmodule.h Issue #29058: All stable API extensions added after Python 3.2 are now 2016-12-27 14:57:39 +02:00
patchlevel.h Python 3.11.0a0 2021-05-03 21:25:35 +01:00
py_curses.h bpo-39573: Finish converting to new Py_IS_TYPE() macro (GH-18601) 2020-03-04 14:15:20 +01:00
pycapsule.h bpo-39573: Add Py_IS_TYPE() function (GH-18488) 2020-02-13 18:37:17 +01:00
pydtrace.d bpo-36842: Implement PEP 578 (GH-12613) 2019-05-23 08:45:22 -07:00
pydtrace.h bpo-36842: Implement PEP 578 (GH-12613) 2019-05-23 08:45:22 -07:00
pyerrors.h bpo-43510: Implement PEP 597 opt-in EncodingWarning. (GH-19481) 2021-03-29 12:28:14 +09:00
pyexpat.h bpo-34623: Use XML_SetHashSalt in _elementtree (GH-9146) 2018-09-18 05:38:58 -07:00
pyframe.h bpo-40421: Add PyFrame_GetCode() function (GH-19757) 2020-04-28 19:01:31 +02:00
pyhash.h bpo-43795: PEP-652: Clean up the stable ABI/limited API (GH-25482) 2021-04-23 14:17:58 +02:00
pylifecycle.h bpo-43795: Remove Py_FrozenMain from the Limited API & Stable ABI (GH-26241) 2021-05-25 04:42:03 -07:00
pymacconfig.h Minor spelling fixes 2016-08-20 08:03:06 +00:00
pymacro.h bpo-41875: Use __builtin_unreachable when possible (GH-22433) 2020-09-29 05:41:23 +09:00
pymath.h bpo-29782: Consolidate _Py_Bit_Length() (GH-20739) 2020-06-15 14:33:48 +02:00
pymem.h bpo-43774: Remove unused PYMALLOC_DEBUG macro (GH-25711) 2021-04-29 10:47:47 +02:00
pyport.h Do not use Py_ssize_clean_t (GH-25940) 2021-05-08 10:17:37 +09:00
pystate.h Update code comment re: location of struct _is. (GH-20067) 2020-05-14 19:11:00 -07:00
pystrcmp.h Merged revisions 59541-59561 via svnmerge from 2007-12-19 02:07:34 +00:00
pystrhex.h bpo-22385: Support output separators in hex methods. (#13578) 2019-05-29 11:46:58 -07:00
pystrtod.h Issue #26331: Implement the parsing part of PEP 515. 2016-09-09 14:57:09 -07:00
Python.h bpo-43774: Remove unused PYMALLOC_DEBUG macro (GH-25711) 2021-04-29 10:47:47 +02:00
pythonrun.h bpo-43868: Remove PyOS_ReadlineFunctionPointer from the stable ABI list (GH-25442) 2021-04-23 14:23:38 +02:00
pythread.h bpo-40089: Add _at_fork_reinit() method to locks (GH-19195) 2020-04-07 23:11:49 +02:00
rangeobject.h bpo-39573: Add Py_IS_TYPE() function (GH-18488) 2020-02-13 18:37:17 +01:00
README.rst bpo-43795: PEP 652 user documentation (GH-25668) 2021-05-11 07:04:33 -07:00
setobject.h bpo-43277: Add PySet_CheckExact to the C-API (GH-24598) 2021-02-20 18:03:08 +00:00
sliceobject.h bpo-39573: Add Py_IS_TYPE() function (GH-18488) 2020-02-13 18:37:17 +01:00
structmember.h bpo-42800: Rename AUDIT_READ to PY_AUDIT_READ (GH-25736) 2021-04-30 01:08:55 +01:00
structseq.h bpo-43916: Move the _PyStructSequence_InitType function to the internal API (GH-25854) 2021-05-03 15:50:24 +01:00
sysmodule.h bpo-44113: Deprecate old functions to config Python init (GH-26060) 2021-05-12 23:59:25 +02:00
token.h bpo-43822: Improve syntax errors for missing commas (GH-25377) 2021-04-15 21:38:45 +01:00
traceback.h bpo-40421: Add pyframe.h header file (GH-19755) 2020-04-28 16:32:48 +02:00
tracemalloc.h bpo-35053: Define _PyTraceMalloc_NewReference in object.h (GH-10107) 2018-10-26 00:01:56 +02:00
tupleobject.h bpo-40428: Remove PyTuple_ClearFreeList() function (GH-19769) 2020-04-29 02:29:20 +02:00
typeslots.h bpo-42085: Introduce dedicated entry in PyAsyncMethods for sending values (#22780) 2020-11-10 12:09:55 -08:00
unicodeobject.h bpo-41784: make PyUnicode_AsUTF8AndSize part of the limited API (GH-22252) 2020-10-19 23:17:50 +01:00
warnings.h bpo-32591: Add native coroutine origin tracking (#5250) 2018-01-21 09:44:07 -05:00
weakrefobject.h bpo-39573: Add Py_IS_TYPE() function (GH-18488) 2020-02-13 18:37:17 +01:00

The Python C API
================

The C API is divided into three sections:

1. ``Include/``: Limited API
2. ``Include/cpython/``: CPython implementation details
3. ``Include/internal/``: The internal API

Information on changing the C API is available `in the developer guide`_

.. _in the developer guide: https://devguide.python.org/c-api/