Adaptive opcodes neglect EXTENDED_ARG #91625

sweeneyde · 2022-04-17T02:01:11Z

Reproducer:

def f(x):
    # UNPACK_SEQUENCE 400
    # is actually
    #     EXTENDED_ARG 1
    #     UNPACK_SEQUENCE 144
    (
        y,y,y,y,y, y,y,y,y,y, y,y,y,y,y, y,y,y,y,y,
        y,y,y,y,y, y,y,y,y,y, y,y,y,y,y, y,y,y,y,y,
        y,y,y,y,y, y,y,y,y,y, y,y,y,y,y, y,y,y,y,y,
        y,y,y,y,y, y,y,y,y,y, y,y,y,y,y, y,y,y,y,y,
        y,y,y,y,y, y,y,y,y,y, y,y,y,y,y, y,y,y,y,y,

        y,y,y,y,y, y,y,y,y,y, y,y,y,y,y, y,y,y,y,y,
        y,y,y,y,y, y,y,y,y,y, y,y,y,y,y, y,y,y,y,y,
        y,y,y,y,y, y,y,y,y,y, y,y,y,y,y, y,y,y,y,y,
        y,y,y,y,y, y,y,y,y,y, y,y,y,y,y, y,y,y,y,y,
        y,y,y,y,y, y,y,y,y,y, y,y,y,y,y, y,y,y,y,y,

        y,y,y,y,y, y,y,y,y,y, y,y,y,y,y, y,y,y,y,y,
        y,y,y,y,y, y,y,y,y,y, y,y,y,y,y, y,y,y,y,y,
        y,y,y,y,y, y,y,y,y,y, y,y,y,y,y, y,y,y,y,y,
        y,y,y,y,y, y,y,y,y,y, y,y,y,y,y, y,y,y,y,y,
        y,y,y,y,y, y,y,y,y,y, y,y,y,y,y, y,y,y,y,y,

        y,y,y,y,y, y,y,y,y,y, y,y,y,y,y, y,y,y,y,y,
        y,y,y,y,y, y,y,y,y,y, y,y,y,y,y, y,y,y,y,y,
        y,y,y,y,y, y,y,y,y,y, y,y,y,y,y, y,y,y,y,y,
        y,y,y,y,y, y,y,y,y,y, y,y,y,y,y, y,y,y,y,y,
        y,y,y,y,y, y,y,y,y,y, y,y,y,y,y, y,y,y,y,y,
    ) = x

# 0..7 get printed out before we get 
# ValueError: too many values to unpack (expected 144)
for i in range(30):
    print(i)
    f(range(400))

This is the problematic bit of C code:

                next_instr--;
                _Py_Specialize_UnpackSequence(seq, next_instr, oparg);
                DISPATCH();

The text was updated successfully, but these errors were encountered:

sweeneyde · 2022-04-17T02:01:35Z

@brandtbucher @markshannon

sweeneyde · 2022-04-17T02:26:54Z

Similar thing for LOAD_GLOBAL:

code = """
def f():
    y=(a0+a1+a2+a3+a4+a5+a6+a7+a8+a9+a10+a11+a12+a13+a14+a15+a16+a17+a18+a19+
    a20+a21+a22+a23+a24+a25+a26+a27+a28+a29+a30+a31+a32+a33+a34+a35+a36+a37+a38+a39+
    a40+a41+a42+a43+a44+a45+a46+a47+a48+a49+a50+a51+a52+a53+a54+a55+a56+a57+a58+a59+
    a60+a61+a62+a63+a64+a65+a66+a67+a68+a69+a70+a71+a72+a73+a74+a75+a76+a77+a78+a79+
    a80+a81+a82+a83+a84+a85+a86+a87+a88+a89+a90+a91+a92+a93+a94+a95+a96+a97+a98+a99+
    a100+a101+a102+a103+a104+a105+a106+a107+a108+a109+a110+a111+a112+a113+a114+a115+a116+a117+a118+a119+
    a120+a121+a122+a123+a124+a125+a126+a127+a128+a129+a130+a131+a132+a133+a134+a135+a136+a137+a138+a139+
    a140+a141+a142+a143+a144+a145+a146+a147+a148+a149+a150+a151+a152+a153+a154+a155+a156+a157+a158+a159+
    a160+a161+a162+a163+a164+a165+a166+a167+a168+a169+a170+a171+a172+a173+a174+a175+a176+a177+a178+a179+
    a180+a181+a182+a183+a184+a185+a186+a187+a188+a189+a190+a191+a192+a193+a194+a195+a196+a197+a198+a199+
    a200+a201+a202+a203+a204+a205+a206+a207+a208+a209+a210+a211+a212+a213+a214+a215+a216+a217+a218+a219+
    a220+a221+a222+a223+a224+a225+a226+a227+a228+a229+a230+a231+a232+a233+a234+a235+a236+a237+a238+a239+
    a240+a241+a242+a243+a244+a245+a246+a247+a248+a249+a250+a251+a252+a253+a254+a255+a256+a257+a258+a259+
    a260+a261+a262+a263+a264+a265+a266+a267+a268+a269+a270+a271+a272+a273+a274+a275+a276+a277+a278+a279+
    a280+a281+a282+a283+a284+a285+a286+a287+a288+a289+a290+a291+a292+a293+a294+a295+a296+a297+a298+a299+
    a300+a301+a302+a303+a304+a305+a306+a307+a308+a309+a310+a311+a312+a313+a314+a315+a316+a317+a318+a319)
    return y
"""
class D(dict):
    def __missing__(self, key):
        return int(key.removeprefix("a"))
ns = D()
exec(code, ns)
f = ns["f"]

for i in range(12):
    print(f())
# 51040
# 51040
# 51040
# 51040
# 51040
# 51040
# 51040
# 18272
# 51040
# 51040
# 51040
# 51040

sweeneyde · 2022-04-17T02:33:45Z

Same thing with LOAD_ATTR:

class A:
    def __getattr__(self, attr):
        return int(attr.removeprefix("a"))
a = A()

def f():
    y=(a.a0+a.a1+a.a2+a.a3+a.a4+a.a5+a.a6+a.a7+a.a8+a.a9+a.a10+a.a11+a.a12+a.a13+a.a14+a.a15+a.a16+a.a17+a.a18+a.a19+
    a.a20+a.a21+a.a22+a.a23+a.a24+a.a25+a.a26+a.a27+a.a28+a.a29+a.a30+a.a31+a.a32+a.a33+a.a34+a.a35+a.a36+a.a37+a.a38+a.a39+
    a.a40+a.a41+a.a42+a.a43+a.a44+a.a45+a.a46+a.a47+a.a48+a.a49+a.a50+a.a51+a.a52+a.a53+a.a54+a.a55+a.a56+a.a57+a.a58+a.a59+
    a.a60+a.a61+a.a62+a.a63+a.a64+a.a65+a.a66+a.a67+a.a68+a.a69+a.a70+a.a71+a.a72+a.a73+a.a74+a.a75+a.a76+a.a77+a.a78+a.a79+
    a.a80+a.a81+a.a82+a.a83+a.a84+a.a85+a.a86+a.a87+a.a88+a.a89+a.a90+a.a91+a.a92+a.a93+a.a94+a.a95+a.a96+a.a97+a.a98+a.a99+
    a.a100+a.a101+a.a102+a.a103+a.a104+a.a105+a.a106+a.a107+a.a108+a.a109+a.a110+a.a111+a.a112+a.a113+a.a114+a.a115+a.a116+a.a117+a.a118+a.a119+
    a.a120+a.a121+a.a122+a.a123+a.a124+a.a125+a.a126+a.a127+a.a128+a.a129+a.a130+a.a131+a.a132+a.a133+a.a134+a.a135+a.a136+a.a137+a.a138+a.a139+
    a.a140+a.a141+a.a142+a.a143+a.a144+a.a145+a.a146+a.a147+a.a148+a.a149+a.a150+a.a151+a.a152+a.a153+a.a154+a.a155+a.a156+a.a157+a.a158+a.a159+
    a.a160+a.a161+a.a162+a.a163+a.a164+a.a165+a.a166+a.a167+a.a168+a.a169+a.a170+a.a171+a.a172+a.a173+a.a174+a.a175+a.a176+a.a177+a.a178+a.a179+
    a.a180+a.a181+a.a182+a.a183+a.a184+a.a185+a.a186+a.a187+a.a188+a.a189+a.a190+a.a191+a.a192+a.a193+a.a194+a.a195+a.a196+a.a197+a.a198+a.a199+
    a.a200+a.a201+a.a202+a.a203+a.a204+a.a205+a.a206+a.a207+a.a208+a.a209+a.a210+a.a211+a.a212+a.a213+a.a214+a.a215+a.a216+a.a217+a.a218+a.a219+
    a.a220+a.a221+a.a222+a.a223+a.a224+a.a225+a.a226+a.a227+a.a228+a.a229+a.a230+a.a231+a.a232+a.a233+a.a234+a.a235+a.a236+a.a237+a.a238+a.a239+
    a.a240+a.a241+a.a242+a.a243+a.a244+a.a245+a.a246+a.a247+a.a248+a.a249+a.a250+a.a251+a.a252+a.a253+a.a254+a.a255+a.a256+a.a257+a.a258+a.a259+
    a.a260+a.a261+a.a262+a.a263+a.a264+a.a265+a.a266+a.a267+a.a268+a.a269+a.a270+a.a271+a.a272+a.a273+a.a274+a.a275+a.a276+a.a277+a.a278+a.a279+
    a.a280+a.a281+a.a282+a.a283+a.a284+a.a285+a.a286+a.a287+a.a288+a.a289+a.a290+a.a291+a.a292+a.a293+a.a294+a.a295+a.a296+a.a297+a.a298+a.a299)
    return y

for i in range(12):
    print(f())
# 44850
# 44850
# 44850
# 44850
# 44850
# 44850
# 44850
# Traceback (most recent call last):
#   File "C:\Users\sween\Source\Repos\cpython2\cpython\unpack.py", line 26, in <module>
#     print(f())
#           ^^^
#   File "C:\Users\sween\Source\Repos\cpython2\cpython\unpack.py", line 20, in f
#     a.a240+a.a241+a.a242+a.a243+a.a244+a.a245+a.a246+a.a247+a.a248+a.a249+a.a250+a.a251+a.a252+a.a253+a.a254+a.a255+a.a256+a.a257+a.a258+a.a259+
#                                                                                                              ^^^^^^
#   File "C:\Users\sween\Source\Repos\cpython2\cpython\unpack.py", line 4, in __getattr__
#     return int(attr.removeprefix("a"))
#            ^^^^^^^^^^^^^^^^^^^^^^^^^^^
# ValueError: invalid literal for int() with base 10: ''

sweeneyde added the type-bug label Apr 17, 2022

sweeneyde changed the title ~~UNPACK_SEQUENCE specializations neglect EXTENDED_ARG~~ Adaptive opcodes neglect EXTENDED_ARG Apr 17, 2022

sweeneyde added the release-blocker label Apr 17, 2022

sweeneyde mentioned this issue Apr 17, 2022

gh-91625: Don't ignore extended args of adaptive opcodes #91626

Merged

sweeneyde added interpreter-core 3.11 labels Apr 17, 2022

sweeneyde added a commit that referenced this issue Apr 17, 2022

gh-91625: Don't ignore extended args of adaptive opcodes (GH-91626)

cec5d85

sweeneyde closed this Apr 17, 2022

python / cpython Public

Adaptive opcodes neglect EXTENDED_ARG #91625

Adaptive opcodes neglect EXTENDED_ARG #91625

sweeneyde commented Apr 17, 2022 •

edited

sweeneyde commented Apr 17, 2022 •

edited

sweeneyde commented Apr 17, 2022 •

edited

sweeneyde commented Apr 17, 2022 •

edited

python / cpython Public

Adaptive opcodes neglect EXTENDED_ARG #91625

Adaptive opcodes neglect EXTENDED_ARG #91625

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sweeneyde commented Apr 17, 2022 • edited

sweeneyde commented Apr 17, 2022 • edited

sweeneyde commented Apr 17, 2022 • edited

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