bpo-46329: Change calling sequence (again) (GH-31373)

* Change calling sequence: Add PUSH_NULL. Merge PRECALL_FUNCTION and PRECALL_METHOD into PRECALL.

Author: markshannon

Doc/whatsnew/3.11.rst

@@ -410,7 +410,7 @@ CPython bytecode changes
 
 * Replaced the three call instructions: :opcode:`CALL_FUNCTION`,
   :opcode:`CALL_FUNCTION_KW` and :opcode:`CALL_METHOD` with
-  :opcode:`PRECALL_FUNCTION`, :opcode:`PRECALL_METHOD`, :opcode:`CALL`,
+  :opcode:`PUSH_NULL`, :opcode:`PRECALL`, :opcode:`CALL`,
   and :opcode:`KW_NAMES`.
   This decouples the argument shifting for methods from the handling of
   keyword arguments and allows better specialization of calls.

Include/opcode.h

@@ -385,6 +385,7 @@ def _write_atomic(path, data, mode=0o666):
 #     Python 3.11a5 3477 (Replace DUP_TOP/DUP_TOP_TWO with COPY and
 #                         ROT_TWO/ROT_THREE/ROT_FOUR/ROT_N with SWAP)
 #     Python 3.11a5 3478 (New CALL opcodes)
+#     Python 3.11a5 3479 (Add PUSH_NULL opcode)
 
 #     Python 3.12 will start with magic number 3500
 
@@ -402,7 +403,7 @@ 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 = (3478).to_bytes(2, 'little') + b'\r\n'
+MAGIC_NUMBER = (3479).to_bytes(2, 'little') + b'\r\n'
 _RAW_MAGIC_NUMBER = int.from_bytes(MAGIC_NUMBER, 'little')  # For import.c
 
 _PYCACHE = '__pycache__'

Lib/importlib/_bootstrap_external.py

@@ -55,6 +55,7 @@ def jabs_op(name, op):
 # Blank lines correspond to available opcodes
 
 def_op('POP_TOP', 1)
+def_op('PUSH_NULL', 2)
 
 def_op('NOP', 9)
 def_op('UNARY_POSITIVE', 10)
@@ -187,9 +188,7 @@ def jabs_op(name, op):
 def_op('SET_UPDATE', 163)
 def_op('DICT_MERGE', 164)
 def_op('DICT_UPDATE', 165)
-
-def_op('PRECALL_FUNCTION', 167)
-def_op('PRECALL_METHOD', 168)
+def_op('PRECALL', 166)
 
 def_op('CALL', 171)
 def_op('KW_NAMES', 172)

Lib/opcode.py

@@ -838,7 +838,7 @@ def foo(x):
                 instructions = [opcode.opname for opcode in opcodes]
                 self.assertNotIn('LOAD_METHOD', instructions)
                 self.assertIn('LOAD_ATTR', instructions)
-                self.assertIn('PRECALL_FUNCTION', instructions)
+                self.assertIn('PRECALL', instructions)
 
     def test_lineno_procedure_call(self):
         def call():