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gh-126835: Remove unused docstring const #130016

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3d34447
remove unused docstring const
WolframAlph Feb 11, 2025
5e0dbc4
Merge branch 'main' into unused-const
Eclips4 Feb 11, 2025
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2 changes: 1 addition & 1 deletion Include/internal/pycore_flowgraph.h
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Original file line number Diff line number Diff line change
Expand Up @@ -22,7 +22,7 @@ void _PyCfgBuilder_Free(struct _PyCfgBuilder *g);
int _PyCfgBuilder_CheckSize(struct _PyCfgBuilder* g);

int _PyCfg_OptimizeCodeUnit(struct _PyCfgBuilder *g, PyObject *consts, PyObject *const_cache,
int nlocals, int nparams, int firstlineno);
int nlocals, int nparams, int firstlineno, unsigned has_docstring);

struct _PyCfgBuilder* _PyCfg_FromInstructionSequence(_PyInstructionSequence *seq);
int _PyCfg_ToInstructionSequence(struct _PyCfgBuilder *g, _PyInstructionSequence *seq);
Expand Down
8 changes: 4 additions & 4 deletions Lib/test/test_code.py
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Original file line number Diff line number Diff line change
Expand Up @@ -30,7 +30,7 @@
freevars: ('x',)
nlocals: 1
flags: 19
consts: ('None',)
consts: ()

>>> def h(x, y):
... a = x + y
Expand All @@ -50,7 +50,7 @@
freevars: ()
nlocals: 5
flags: 3
consts: ('None',)
consts: ()

>>> def attrs(obj):
... print(obj.attr1)
Expand Down Expand Up @@ -104,7 +104,7 @@
freevars: ()
nlocals: 3
flags: 3
consts: ('None',)
consts: ()

>>> def posonly_args(a,b,/,c):
... return a,b,c
Expand All @@ -121,7 +121,7 @@
freevars: ()
nlocals: 3
flags: 3
consts: ('None',)
consts: ()

>>> def has_docstring(x: str):
... 'This is a one-line doc string'
Expand Down
2 changes: 1 addition & 1 deletion Lib/test/test_compile.py
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Original file line number Diff line number Diff line change
Expand Up @@ -841,7 +841,7 @@ def f():
return "unused"

self.assertEqual(f.__code__.co_consts,
(True, "used"))
("used", ))

@support.cpython_only
def test_remove_unused_consts_extended_args(self):
Expand Down
9 changes: 3 additions & 6 deletions Lib/test/test_dis.py
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Expand Up @@ -1425,9 +1425,9 @@ def get_disassembly(self, func, lasti=-1, wrapper=True, **kwargs):


if dis.code_info.__doc__ is None:
code_info_consts = "0: None"
code_info_consts = ""
else:
code_info_consts = "0: 'Formatted details of methods, functions, or code.'"
code_info_consts = "Constants:\n 0: 'Formatted details of methods, functions, or code.'"

code_info_code_info = f"""\
Name: code_info
Expand All @@ -1438,8 +1438,7 @@ def get_disassembly(self, func, lasti=-1, wrapper=True, **kwargs):
Number of locals: 1
Stack size: \\d+
Flags: OPTIMIZED, NEWLOCALS, HAS_DOCSTRING
Constants:
{code_info_consts}
{code_info_consts}
Names:
0: _format_code_info
1: _get_code_object
Expand Down Expand Up @@ -1546,8 +1545,6 @@ def f(c=c):
Number of locals: 0
Stack size: \\d+
Flags: 0x0
Constants:
0: None
Names:
0: x"""

Expand Down
22 changes: 11 additions & 11 deletions Lib/test/test_peepholer.py
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Original file line number Diff line number Diff line change
Expand Up @@ -1057,16 +1057,16 @@ def test_conditional_jump_forward_non_const_condition(self):
expected_insts = [
('LOAD_NAME', 1, 11),
('POP_JUMP_IF_TRUE', lbl := self.Label(), 12),
('LOAD_CONST', 1, 13),
('LOAD_CONST', 0, 13),
('RETURN_VALUE', None, 13),
lbl,
('LOAD_CONST', 2, 14),
('LOAD_CONST', 1, 14),
('RETURN_VALUE', None, 14),
]
self.cfg_optimization_test(insts,
expected_insts,
consts=[0, 1, 2, 3, 4],
expected_consts=[0, 2, 3])
expected_consts=[2, 3])

def test_list_exceeding_stack_use_guideline(self):
def f():
Expand Down Expand Up @@ -1107,10 +1107,10 @@ def test_multiple_foldings(self):
('RETURN_VALUE', None, 0)
]
after = [
('LOAD_CONST', 1, 0),
('LOAD_CONST', 0, 0),
('RETURN_VALUE', None, 0)
]
self.cfg_optimization_test(before, after, consts=[], expected_consts=[(2,), (1, 2)])
self.cfg_optimization_test(before, after, consts=[], expected_consts=[(1, 2)])

def test_build_empty_tuple(self):
before = [
Expand Down Expand Up @@ -1277,13 +1277,13 @@ def test_conditional_jump_forward_const_condition(self):
expected_insts = [
('NOP', None, 11),
('NOP', None, 12),
('LOAD_CONST', 1, 14),
('LOAD_CONST', 0, 14),
('RETURN_VALUE', None, 14),
]
self.cfg_optimization_test(insts,
expected_insts,
consts=[0, 1, 2, 3, 4],
expected_consts=[0, 3])
expected_consts=[3])

def test_conditional_jump_backward_non_const_condition(self):
insts = [
Expand Down Expand Up @@ -1322,18 +1322,18 @@ def test_except_handler_label(self):
insts = [
('SETUP_FINALLY', handler := self.Label(), 10),
('POP_BLOCK', None, -1),
('LOAD_CONST', 1, 11),
('LOAD_CONST', 0, 11),
('RETURN_VALUE', None, 11),
handler,
('LOAD_CONST', 2, 12),
('LOAD_CONST', 1, 12),
('RETURN_VALUE', None, 12),
]
expected_insts = [
('SETUP_FINALLY', handler := self.Label(), 10),
('LOAD_CONST', 1, 11),
('LOAD_CONST', 0, 11),
('RETURN_VALUE', None, 11),
handler,
('LOAD_CONST', 2, 12),
('LOAD_CONST', 1, 12),
('RETURN_VALUE', None, 12),
]
self.cfg_optimization_test(insts, expected_insts, consts=list(range(5)))
Expand Down
2 changes: 1 addition & 1 deletion Python/compile.c
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Expand Up @@ -1325,7 +1325,7 @@ optimize_and_assemble_code_unit(struct compiler_unit *u, PyObject *const_cache,
assert(u->u_metadata.u_firstlineno);

if (_PyCfg_OptimizeCodeUnit(g, consts, const_cache, nlocals,
nparams, u->u_metadata.u_firstlineno) < 0) {
nparams, u->u_metadata.u_firstlineno, u->u_ste->ste_has_docstring) < 0) {
goto error;
}

Expand Down
16 changes: 10 additions & 6 deletions Python/flowgraph.c
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Original file line number Diff line number Diff line change
Expand Up @@ -2281,7 +2281,7 @@ fast_scan_many_locals(basicblock *entryblock, int nlocals)
}

static int
remove_unused_consts(basicblock *entryblock, PyObject *consts)
remove_unused_consts(basicblock *entryblock, PyObject *consts, unsigned has_docstring)
{
assert(PyList_CheckExact(consts));
Py_ssize_t nconsts = PyList_GET_SIZE(consts);
Expand All @@ -2297,11 +2297,15 @@ remove_unused_consts(basicblock *entryblock, PyObject *consts)
if (index_map == NULL) {
goto end;
}
for (Py_ssize_t i = 1; i < nconsts; i++) {
for (Py_ssize_t i = 0; i < nconsts; i++) {
index_map[i] = -1;
}
// The first constant may be docstring; keep it always.
index_map[0] = 0;
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Maybe update the comment above? It's only kept when we have the docstring now

if (has_docstring) {
assert(PyList_Size(consts) >= 1);
assert(PyUnicode_CheckExact(PyList_GET_ITEM(consts, 0)));
index_map[0] = 0;
}

/* mark used consts */
for (basicblock *b = entryblock; b != NULL; b = b->b_next) {
Expand Down Expand Up @@ -2764,7 +2768,7 @@ resolve_line_numbers(cfg_builder *g, int firstlineno)

int
_PyCfg_OptimizeCodeUnit(cfg_builder *g, PyObject *consts, PyObject *const_cache,
int nlocals, int nparams, int firstlineno)
int nlocals, int nparams, int firstlineno, unsigned has_docstring)
{
assert(cfg_builder_check(g));
/** Preprocessing **/
Expand All @@ -2775,7 +2779,7 @@ _PyCfg_OptimizeCodeUnit(cfg_builder *g, PyObject *consts, PyObject *const_cache,

/** Optimization **/
RETURN_IF_ERROR(optimize_cfg(g, consts, const_cache, firstlineno));
RETURN_IF_ERROR(remove_unused_consts(g->g_entryblock, consts));
RETURN_IF_ERROR(remove_unused_consts(g->g_entryblock, consts, has_docstring));
RETURN_IF_ERROR(
add_checks_for_loads_of_uninitialized_variables(
g->g_entryblock, nlocals, nparams));
Expand Down Expand Up @@ -3191,7 +3195,7 @@ _PyCompile_OptimizeCfg(PyObject *seq, PyObject *consts, int nlocals)
}
int nparams = 0, firstlineno = 1;
if (_PyCfg_OptimizeCodeUnit(g, consts, const_cache, nlocals,
nparams, firstlineno) < 0) {
nparams, firstlineno, 0) < 0) {
goto error;
}
res = cfg_to_instruction_sequence(g);
Expand Down
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