Skip to content

Commit

Permalink
bpo-43693: Compute deref offsets in compiler (pythongh-25152)
Browse files Browse the repository at this point in the history 
Merges locals and cells into a single array.
Saves a pointer in the interpreter and means that we don't need the LOAD_CLOSURE opcode any more

https://bugs.python.org/issue43693
  • Loading branch information
@markshannon
markshannon authored Jun 4, 2021
1 parent 35002aa commit b2bf2bc
Show file tree
Hide file tree
Showing 11 changed files with 222 additions and 209 deletions.
29 changes: 23 additions & 6 deletions Doc/library/dis.rst
View file
Original file line number Diff line number Diff line change
Expand Up @@ -1058,16 +1058,24 @@ All of the following opcodes use their arguments.

.. opcode:: LOAD_CLOSURE (i)

Pushes a reference to the cell contained in slot *i* of the cell and free
variable storage. The name of the variable is
``co_fastlocalnames[i + len(co_varnames)]``.
Pushes a reference to the cell contained in slot ``i`` of the "fast locals"
storage. The name of the variable is ``co_fastlocalnames[i]``.

Note that ``LOAD_CLOSURE`` is effectively an alias for ``LOAD_FAST``.
It exists to keep bytecode a little more readable.

.. versionchanged:: 3.11
``i`` is no longer offset by the length of ``co_varnames``.


.. opcode:: LOAD_DEREF (i)

Loads the cell contained in slot *i* of the cell and free variable storage.
Loads the cell contained in slot ``i`` of the "fast locals" storage.
Pushes a reference to the object the cell contains on the stack.

.. versionchanged:: 3.11
``i`` is no longer offset by the length of ``co_varnames``.


.. opcode:: LOAD_CLASSDEREF (i)

Expand All @@ -1077,20 +1085,29 @@ All of the following opcodes use their arguments.

.. versionadded:: 3.4

.. versionchanged:: 3.11
``i`` is no longer offset by the length of ``co_varnames``.


.. opcode:: STORE_DEREF (i)

Stores TOS into the cell contained in slot *i* of the cell and free variable
Stores TOS into the cell contained in slot ``i`` of the "fast locals"
storage.

.. versionchanged:: 3.11
``i`` is no longer offset by the length of ``co_varnames``.


.. opcode:: DELETE_DEREF (i)

Empties the cell contained in slot *i* of the cell and free variable storage.
Empties the cell contained in slot ``i`` of the "fast locals" storage.
Used by the :keyword:`del` statement.

.. versionadded:: 3.2

.. versionchanged:: 3.11
``i`` is no longer offset by the length of ``co_varnames``.


.. opcode:: RAISE_VARARGS (argc)

Expand Down
5 changes: 1 addition & 4 deletions Lib/dis.py
View file
Original file line number Diff line number Diff line change
Expand Up @@ -378,14 +378,11 @@ def _get_instructions_bytes(code, varname_from_oparg=None,
elif op in hasjrel:
argval = offset + 2 + arg*2
argrepr = "to " + repr(argval)
elif op in haslocal:
elif op in haslocal or op in hasfree:
argval, argrepr = _get_name_info(arg, varname_from_oparg)
elif op in hascompare:
argval = cmp_op[arg]
argrepr = argval
elif op in hasfree:
argval, argrepr = _get_name_info(arg, varname_from_oparg,
cell=True)
elif op == FORMAT_VALUE:
argval, argrepr = FORMAT_VALUE_CONVERTERS[arg & 0x3]
argval = (argval, bool(arg & 0x4))
Expand Down
3 changes: 2 additions & 1 deletion Lib/importlib/_bootstrap_external.py
View file
Original file line number Diff line number Diff line change
Expand Up @@ -356,6 +356,7 @@ def _write_atomic(path, data, mode=0o666):
# Python 3.11a1 3451 (Add CALL_METHOD_KW)
# Python 3.11a1 3452 (drop nlocals from marshaled code objects)
# Python 3.11a1 3453 (add co_fastlocalnames and co_fastlocalkinds)
# Python 3.11a1 3454 (compute cell offsets relative to locals bpo-43693)

#
# MAGIC must change whenever the bytecode emitted by the compiler may no
Expand All @@ -365,7 +366,7 @@ 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 = (3453).to_bytes(2, 'little') + b'\r\n'
MAGIC_NUMBER = (3454).to_bytes(2, 'little') + b'\r\n'
_RAW_MAGIC_NUMBER = int.from_bytes(MAGIC_NUMBER, 'little') # For import.c

_PYCACHE = '__pycache__'
Expand Down
40 changes: 20 additions & 20 deletions Lib/test/test_dis.py
View file
Original file line number Diff line number Diff line change
Expand Up @@ -427,7 +427,7 @@ def foo(x):
return foo

dis_nested_0 = """\
%3d 0 LOAD_CLOSURE 0 (y)
%3d 0 LOAD_CLOSURE 2 (y)
2 BUILD_TUPLE 1
4 LOAD_CONST 1 (<code object foo at 0x..., file "%s", line %d>)
6 LOAD_CONST 2 ('_h.<locals>.foo')
Expand All @@ -444,12 +444,12 @@ def foo(x):

dis_nested_1 = """%s
Disassembly of <code object foo at 0x..., file "%s", line %d>:
%3d 0 LOAD_CLOSURE 0 (x)
%3d 0 LOAD_CLOSURE 1 (x)
2 BUILD_TUPLE 1
4 LOAD_CONST 1 (<code object <listcomp> at 0x..., file "%s", line %d>)
6 LOAD_CONST 2 ('_h.<locals>.foo.<locals>.<listcomp>')
8 MAKE_FUNCTION 8 (closure)
10 LOAD_DEREF 1 (y)
10 LOAD_DEREF 2 (y)
12 GET_ITER
14 CALL_FUNCTION 1
16 RETURN_VALUE
Expand All @@ -467,7 +467,7 @@ def foo(x):
2 LOAD_FAST 0 (.0)
>> 4 FOR_ITER 6 (to 18)
6 STORE_FAST 1 (z)
8 LOAD_DEREF 0 (x)
8 LOAD_DEREF 2 (x)
10 LOAD_FAST 1 (z)
12 BINARY_ADD
14 LIST_APPEND 2
Expand Down Expand Up @@ -962,16 +962,16 @@ def jumpy():
Instruction = dis.Instruction
expected_opinfo_outer = [
Instruction(opname='LOAD_CONST', opcode=100, arg=8, argval=(3, 4), argrepr='(3, 4)', offset=0, starts_line=2, is_jump_target=False),
Instruction(opname='LOAD_CLOSURE', opcode=135, arg=0, argval='a', argrepr='a', offset=2, starts_line=None, is_jump_target=False),
Instruction(opname='LOAD_CLOSURE', opcode=135, arg=1, argval='b', argrepr='b', offset=4, starts_line=None, is_jump_target=False),
Instruction(opname='LOAD_CLOSURE', opcode=135, arg=3, argval='a', argrepr='a', offset=2, starts_line=None, is_jump_target=False),
Instruction(opname='LOAD_CLOSURE', opcode=135, arg=4, argval='b', argrepr='b', offset=4, starts_line=None, is_jump_target=False),
Instruction(opname='BUILD_TUPLE', opcode=102, arg=2, argval=2, argrepr='', offset=6, starts_line=None, is_jump_target=False),
Instruction(opname='LOAD_CONST', opcode=100, arg=3, argval=code_object_f, argrepr=repr(code_object_f), offset=8, starts_line=None, is_jump_target=False),
Instruction(opname='LOAD_CONST', opcode=100, arg=4, argval='outer.<locals>.f', argrepr="'outer.<locals>.f'", offset=10, starts_line=None, is_jump_target=False),
Instruction(opname='MAKE_FUNCTION', opcode=132, arg=9, argval=9, argrepr='defaults, closure', offset=12, starts_line=None, is_jump_target=False),
Instruction(opname='STORE_FAST', opcode=125, arg=2, argval='f', argrepr='f', offset=14, starts_line=None, is_jump_target=False),
Instruction(opname='LOAD_GLOBAL', opcode=116, arg=0, argval='print', argrepr='print', offset=16, starts_line=7, is_jump_target=False),
Instruction(opname='LOAD_DEREF', opcode=136, arg=0, argval='a', argrepr='a', offset=18, starts_line=None, is_jump_target=False),
Instruction(opname='LOAD_DEREF', opcode=136, arg=1, argval='b', argrepr='b', offset=20, starts_line=None, is_jump_target=False),
Instruction(opname='LOAD_DEREF', opcode=136, arg=3, argval='a', argrepr='a', offset=18, starts_line=None, is_jump_target=False),
Instruction(opname='LOAD_DEREF', opcode=136, arg=4, argval='b', argrepr='b', offset=20, starts_line=None, is_jump_target=False),
Instruction(opname='LOAD_CONST', opcode=100, arg=5, argval='', argrepr="''", offset=22, starts_line=None, is_jump_target=False),
Instruction(opname='LOAD_CONST', opcode=100, arg=6, argval=1, argrepr='1', offset=24, starts_line=None, is_jump_target=False),
Instruction(opname='BUILD_LIST', opcode=103, arg=0, argval=0, argrepr='', offset=26, starts_line=None, is_jump_target=False),
Expand All @@ -985,20 +985,20 @@ def jumpy():

expected_opinfo_f = [
Instruction(opname='LOAD_CONST', opcode=100, arg=5, argval=(5, 6), argrepr='(5, 6)', offset=0, starts_line=3, is_jump_target=False),
Instruction(opname='LOAD_CLOSURE', opcode=135, arg=2, argval='a', argrepr='a', offset=2, starts_line=None, is_jump_target=False),
Instruction(opname='LOAD_CLOSURE', opcode=135, arg=3, argval='b', argrepr='b', offset=4, starts_line=None, is_jump_target=False),
Instruction(opname='LOAD_CLOSURE', opcode=135, arg=0, argval='c', argrepr='c', offset=6, starts_line=None, is_jump_target=False),
Instruction(opname='LOAD_CLOSURE', opcode=135, arg=1, argval='d', argrepr='d', offset=8, starts_line=None, is_jump_target=False),
Instruction(opname='LOAD_CLOSURE', opcode=135, arg=5, argval='a', argrepr='a', offset=2, starts_line=None, is_jump_target=False),
Instruction(opname='LOAD_CLOSURE', opcode=135, arg=6, argval='b', argrepr='b', offset=4, starts_line=None, is_jump_target=False),
Instruction(opname='LOAD_CLOSURE', opcode=135, arg=3, argval='c', argrepr='c', offset=6, starts_line=None, is_jump_target=False),
Instruction(opname='LOAD_CLOSURE', opcode=135, arg=4, argval='d', argrepr='d', offset=8, starts_line=None, is_jump_target=False),
Instruction(opname='BUILD_TUPLE', opcode=102, arg=4, argval=4, argrepr='', offset=10, starts_line=None, is_jump_target=False),
Instruction(opname='LOAD_CONST', opcode=100, arg=3, argval=code_object_inner, argrepr=repr(code_object_inner), offset=12, starts_line=None, is_jump_target=False),
Instruction(opname='LOAD_CONST', opcode=100, arg=4, argval='outer.<locals>.f.<locals>.inner', argrepr="'outer.<locals>.f.<locals>.inner'", offset=14, starts_line=None, is_jump_target=False),
Instruction(opname='MAKE_FUNCTION', opcode=132, arg=9, argval=9, argrepr='defaults, closure', offset=16, starts_line=None, is_jump_target=False),
Instruction(opname='STORE_FAST', opcode=125, arg=2, argval='inner', argrepr='inner', offset=18, starts_line=None, is_jump_target=False),
Instruction(opname='LOAD_GLOBAL', opcode=116, arg=0, argval='print', argrepr='print', offset=20, starts_line=5, is_jump_target=False),
Instruction(opname='LOAD_DEREF', opcode=136, arg=2, argval='a', argrepr='a', offset=22, starts_line=None, is_jump_target=False),
Instruction(opname='LOAD_DEREF', opcode=136, arg=3, argval='b', argrepr='b', offset=24, starts_line=None, is_jump_target=False),
Instruction(opname='LOAD_DEREF', opcode=136, arg=0, argval='c', argrepr='c', offset=26, starts_line=None, is_jump_target=False),
Instruction(opname='LOAD_DEREF', opcode=136, arg=1, argval='d', argrepr='d', offset=28, starts_line=None, is_jump_target=False),
Instruction(opname='LOAD_DEREF', opcode=136, arg=5, argval='a', argrepr='a', offset=22, starts_line=None, is_jump_target=False),
Instruction(opname='LOAD_DEREF', opcode=136, arg=6, argval='b', argrepr='b', offset=24, starts_line=None, is_jump_target=False),
Instruction(opname='LOAD_DEREF', opcode=136, arg=3, argval='c', argrepr='c', offset=26, starts_line=None, is_jump_target=False),
Instruction(opname='LOAD_DEREF', opcode=136, arg=4, argval='d', argrepr='d', offset=28, starts_line=None, is_jump_target=False),
Instruction(opname='CALL_FUNCTION', opcode=131, arg=4, argval=4, argrepr='', offset=30, starts_line=None, is_jump_target=False),
Instruction(opname='POP_TOP', opcode=1, arg=None, argval=None, argrepr='', offset=32, starts_line=None, is_jump_target=False),
Instruction(opname='LOAD_FAST', opcode=124, arg=2, argval='inner', argrepr='inner', offset=34, starts_line=6, is_jump_target=False),
Expand All @@ -1007,10 +1007,10 @@ def jumpy():

expected_opinfo_inner = [
Instruction(opname='LOAD_GLOBAL', opcode=116, arg=0, argval='print', argrepr='print', offset=0, starts_line=4, is_jump_target=False),
Instruction(opname='LOAD_DEREF', opcode=136, arg=0, argval='a', argrepr='a', offset=2, starts_line=None, is_jump_target=False),
Instruction(opname='LOAD_DEREF', opcode=136, arg=1, argval='b', argrepr='b', offset=4, starts_line=None, is_jump_target=False),
Instruction(opname='LOAD_DEREF', opcode=136, arg=2, argval='c', argrepr='c', offset=6, starts_line=None, is_jump_target=False),
Instruction(opname='LOAD_DEREF', opcode=136, arg=3, argval='d', argrepr='d', offset=8, starts_line=None, is_jump_target=False),
Instruction(opname='LOAD_DEREF', opcode=136, arg=2, argval='a', argrepr='a', offset=2, starts_line=None, is_jump_target=False),
Instruction(opname='LOAD_DEREF', opcode=136, arg=3, argval='b', argrepr='b', offset=4, starts_line=None, is_jump_target=False),
Instruction(opname='LOAD_DEREF', opcode=136, arg=4, argval='c', argrepr='c', offset=6, starts_line=None, is_jump_target=False),
Instruction(opname='LOAD_DEREF', opcode=136, arg=5, argval='d', argrepr='d', offset=8, starts_line=None, is_jump_target=False),
Instruction(opname='LOAD_FAST', opcode=124, arg=0, argval='e', argrepr='e', offset=10, starts_line=None, is_jump_target=False),
Instruction(opname='LOAD_FAST', opcode=124, arg=1, argval='f', argrepr='f', offset=12, starts_line=None, is_jump_target=False),
Instruction(opname='CALL_FUNCTION', opcode=131, arg=6, argval=6, argrepr='', offset=14, starts_line=None, is_jump_target=False),
Expand Down
4 changes: 4 additions & 0 deletions Misc/NEWS.d/next/Core and Builtins/2021-04-02-15-02-16.bpo-43693.l3Ureu.rst
View file
Original file line number Diff line number Diff line change
@@ -0,0 +1,4 @@
Compute cell offsets relative to locals in compiler. Allows the interpreter
to treats locals and cells a single array, which is slightly more efficient.
Also make the LOAD_CLOSURE opcode an alias for LOAD_FAST. Preserving
LOAD_CLOSURE helps keep bytecode a bit more readable.
22 changes: 6 additions & 16 deletions Objects/clinic/codeobject.c.h
View file

Some generated files are not rendered by default. Learn more about how customized files appear on GitHub.

9 changes: 2 additions & 7 deletions Objects/codeobject.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -1547,21 +1547,16 @@ code_replace_impl(PyCodeObject *self, int co_argcount,
code._varname_from_oparg
oparg: int
*
cell: bool = False
(internal-only) Return the local variable name for the given oparg.
WARNING: this method is for internal use only and may change or go away.
[clinic start generated code]*/

static PyObject *
code__varname_from_oparg_impl(PyCodeObject *self, int oparg, int cell)
/*[clinic end generated code: output=c7d39c9723692c8f input=2945bb291d3a3118]*/
code__varname_from_oparg_impl(PyCodeObject *self, int oparg)
/*[clinic end generated code: output=1fd1130413184206 input=c5fa3ee9bac7d4ca]*/
{
if (cell) {
oparg += self->co_nlocals;
}
PyObject *name = PyTuple_GetItem(self->co_localsplusnames, oparg);
if (name == NULL) {
return NULL;
Expand Down
Loading

0 comments on commit b2bf2bc

Please sign in to comment.