Add stats

doc/index.rst

@@ -64,6 +64,7 @@ Pages
    python_ir
    runtime
    opaque_pyobject
+   stats
 
 
 Links
@@ -112,3 +113,4 @@ Table of Contents
    python_ir
    runtime
    opaque_pyobject
+   stats

doc/stats.rst

@@ -0,0 +1,52 @@
+==============================
+Statistics on the Python C API
+==============================
+
+Line numbers
+============
+
+Number of C API line numbers per Python version:
+
+=======  =============  ===========  ============  =======
+Version  Public         CPython      Internal      Total
+=======  =============  ===========  ============  =======
+2.7      12686 (100%)   0            0             12686
+3.6      16011 (100%)   0            0             16011
+3.7      16517 (96%)    0            705 (4%)      17222
+3.8      13160 (70%)    3417 (18%)   2230 (12%)    18807
+3.9      12264 (62%)    4343 (22%)   3066 (16%)    19673
+3.10     10305 (52%)    4513 (23%)   5092 (26%)    19910
+=======  =============  ===========  ============  =======
+
+Comands:
+
+* public: ``wc -l Include/*.h``
+* cpython: ``wc -l Include/cpython/*.h``
+* internal: ``wc -l Include/internal/*.h``
+
+Symbols
+=======
+
+Symbols exported with PyAPI_FUNC() and PyAPI_DATA():
+
+=======  ===========
+Version  Symbols
+=======  ===========
+2.7      1098
+3.6      1460
+3.7      1547 (+87)
+3.8      1561 (+14)
+3.9      1552 (-9)
+3.10     1495 (-57)
+=======  ===========
+
+Command::
+
+    grep -E 'PyAPI_(FUNC|DATA)' Include/*.h Include/cpython/*.h|wc -l
+
+Since Python 3.9, Python is now built with ``-fvisibility=hidden`` to avoid
+exporting symbols which are not **explicitly** exported.
+
+The ``make smelly`` command checks for public symbols of libpython and C
+extension which are prefixed by ``Py`` or ``_Py``. See
+``Tools/scripts/smelly.py`` script.