bpo-46939: Specialize calls to Python classes (POSTCALL edition)

Doc/library/dis.rst

@@ -1158,6 +1158,14 @@ iterations of the loop.
    .. versionadded:: 3.11
 
 
+.. opcode:: POSTCALL
+
+   Suffixes :opcode:`CALL`. Logically this is a no op.
+   It exists to enable effective specialization of calls.
+
+   .. versionadded:: 3.11
+
+
 .. opcode:: PUSH_NULL
 
     Pushes a ``NULL`` to the stack.

Include/cpython/object.h

@@ -234,6 +234,7 @@ struct _typeobject {
  * by code other than the specializer and interpreter. */
 struct _specialization_cache {
     PyObject *getitem;
+    PyObject *init;
 };
 
 /* The *real* layout of a type object when allocated on the heap */

Include/internal/pycore_code.h

@@ -82,6 +82,7 @@ typedef struct {
 
 typedef struct {
     _Py_CODEUNIT counter;
+    _Py_CODEUNIT type_version[2];
 } _PyPrecallCache;
 
 #define INLINE_CACHE_ENTRIES_PRECALL CACHE_ENTRIES(_PyPrecallCache)

Include/internal/pycore_typeobject.h

@@ -43,6 +43,8 @@ extern PyStatus _PyTypes_InitSlotDefs(void);
 
 extern void _PyStaticType_Dealloc(PyTypeObject *type);
 
+extern PyObject *_PyObject_New_Vector(PyTypeObject *type,
+    PyObject *const *args, Py_ssize_t nargs, PyObject *kwds);
 
 #ifdef __cplusplus
 }

Lib/importlib/_bootstrap_external.py

@@ -400,6 +400,7 @@ def _write_atomic(path, data, mode=0o666):
 #     Python 3.11a6 3490 (remove JUMP_IF_NOT_EXC_MATCH, add CHECK_EXC_MATCH)
 #     Python 3.11a6 3491 (remove JUMP_IF_NOT_EG_MATCH, add CHECK_EG_MATCH,
 #                         add JUMP_BACKWARD_NO_INTERRUPT, make JUMP_NO_INTERRUPT virtual)
+#     Python 3.11a6 3492 (Specialize PRECALL for Python classes)
 
 #     Python 3.12 will start with magic number 3500
 
@@ -414,7 +415,7 @@ def _write_atomic(path, data, mode=0o666):
 # Whenever MAGIC_NUMBER is changed, the ranges in the magic_values array
 # in PC/launcher.c must also be updated.
 
-MAGIC_NUMBER = (3491).to_bytes(2, 'little') + b'\r\n'
+MAGIC_NUMBER = (3492).to_bytes(2, 'little') + b'\r\n'
 _RAW_MAGIC_NUMBER = int.from_bytes(MAGIC_NUMBER, 'little')  # For import.c
 
 _PYCACHE = '__pycache__'

Lib/opcode.py

@@ -60,6 +60,7 @@ def jabs_op(name, op, entries=0):
 def_op('CACHE', 0)
 def_op('POP_TOP', 1)
 def_op('PUSH_NULL', 2)
+def_op('POSTCALL', 3)
 
 def_op('NOP', 9)
 def_op('UNARY_POSITIVE', 10)
@@ -191,7 +192,7 @@ def jabs_op(name, op, entries=0):
 def_op('SET_UPDATE', 163)
 def_op('DICT_MERGE', 164)
 def_op('DICT_UPDATE', 165)
-def_op('PRECALL', 166, 1)
+def_op('PRECALL', 166, 3)
 
 def_op('CALL', 171, 4)
 def_op('KW_NAMES', 172)
@@ -307,6 +308,7 @@ def jabs_op(name, op, entries=0):
         "PRECALL_NO_KW_TUPLE_1",
         "PRECALL_NO_KW_TYPE_1",
         "PRECALL_PYFUNC",
+        "PRECALL_PY_CLASS",
     ],
     "RESUME": [
         "RESUME_QUICK",