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gh-98831: rewrite GET_LEN, GET_ITER, BEFORE_WITH and a few simple opcodes in the instruction definition DSL #101443

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merged 5 commits into from
Jan 31, 2023
Merged

gh-98831: rewrite GET_LEN, GET_ITER, BEFORE_WITH and a few simple opcodes in the instruction definition DSL #101443

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26fc7a3
gh-98831: rewrite GET_LEN, GET_ITER, BEFORE_WITH and a few simple opc…
iritkatriel Jan 31, 2023
6bfec26
goto instead of ERROR_IF to avoid leaks
iritkatriel Jan 31, 2023
2ee6241
revert BEFORE_WITH
iritkatriel Jan 31, 2023
0a5f78d
Revert "revert BEFORE_WITH"
iritkatriel Jan 31, 2023
a925498
fix refleak of exit when __enter__ raises
iritkatriel Jan 31, 2023
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62 changes: 22 additions & 40 deletions Python/bytecodes.c
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Original file line number Diff line number Diff line change
Expand Up @@ -2053,8 +2053,7 @@ dummy_func(
}
}

// stack effect: ( -- )
inst(JUMP_BACKWARD_NO_INTERRUPT) {
inst(JUMP_BACKWARD_NO_INTERRUPT, (--)) {
/* This bytecode is used in the `yield from` or `await` loop.
* If there is an interrupt, we want it handled in the innermost
* generator or coroutine, so we deliberately do not check it here.
Expand All @@ -2063,18 +2062,12 @@ dummy_func(
JUMPBY(-oparg);
}

// stack effect: ( -- __0)
inst(GET_LEN) {
inst(GET_LEN, (obj -- obj, len_o)) {
// PUSH(len(TOS))
Py_ssize_t len_i = PyObject_Length(TOP());
if (len_i < 0) {
goto error;
}
PyObject *len_o = PyLong_FromSsize_t(len_i);
if (len_o == NULL) {
goto error;
}
PUSH(len_o);
Py_ssize_t len_i = PyObject_Length(obj);
ERROR_IF(len_i < 0, error);
len_o = PyLong_FromSsize_t(len_i);
ERROR_IF(len_o == NULL, error);
}

inst(MATCH_CLASS, (subject, type, names -- attrs)) {
Expand Down Expand Up @@ -2110,15 +2103,11 @@ dummy_func(
ERROR_IF(values_or_none == NULL, error);
}

// stack effect: ( -- )
inst(GET_ITER) {
inst(GET_ITER, (iterable -- iter)) {
/* before: [obj]; after [getiter(obj)] */
PyObject *iterable = TOP();
PyObject *iter = PyObject_GetIter(iterable);
Py_DECREF(iterable);
SET_TOP(iter);
if (iter == NULL)
goto error;
iter = PyObject_GetIter(iterable);
DECREF_INPUTS();
ERROR_IF(iter == NULL, error);
}

// stack effect: ( -- )
Expand Down Expand Up @@ -2313,10 +2302,10 @@ dummy_func(
PREDICT(GET_AWAITABLE);
}

// stack effect: ( -- __0)
inst(BEFORE_WITH) {
PyObject *mgr = TOP();
PyObject *res;
inst(BEFORE_WITH, (mgr -- exit, res)) {
/* pop the context manager, push its __exit__ and the
* value returned from calling its __enter__
*/
PyObject *enter = _PyObject_LookupSpecial(mgr, &_Py_ID(__enter__));
if (enter == NULL) {
if (!_PyErr_Occurred(tstate)) {
Expand All @@ -2325,9 +2314,9 @@ dummy_func(
"context manager protocol",
Py_TYPE(mgr)->tp_name);
}
goto error;
ERROR_IF(true, error);
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I believe this leaks a reference to mgr. You can either insert another DECREF_INPUTS() before this line, or just keep the goto error. I prefer the latter, we're not going to require using DECREF_INPUTS() everywhere (it mostly exists because it would be useful with the register conversion).

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I'm was just looking at this. I added DECREF_INPUTS in these two places and it is still leaking something.

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I pushed the change with goto, still looking for the other leak.

}
PyObject *exit = _PyObject_LookupSpecial(mgr, &_Py_ID(__exit__));
exit = _PyObject_LookupSpecial(mgr, &_Py_ID(__exit__));
if (exit == NULL) {
if (!_PyErr_Occurred(tstate)) {
_PyErr_Format(tstate, PyExc_TypeError,
Expand All @@ -2337,16 +2326,12 @@ dummy_func(
Py_TYPE(mgr)->tp_name);
}
Py_DECREF(enter);
goto error;
ERROR_IF(true, error);
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Same here.

}
SET_TOP(exit);
Py_DECREF(mgr);
DECREF_INPUTS();
res = _PyObject_CallNoArgs(enter);
Py_DECREF(enter);
if (res == NULL) {
goto error;
}
PUSH(res);
ERROR_IF(res == NULL, error);
}

inst(WITH_EXCEPT_START, (exit_func, lasti, unused, val -- exit_func, lasti, unused, val, res)) {
Expand Down Expand Up @@ -2469,8 +2454,7 @@ dummy_func(
GO_TO_INSTRUCTION(CALL_PY_EXACT_ARGS);
}

// stack effect: ( -- )
inst(KW_NAMES) {
inst(KW_NAMES, (--)) {
assert(kwnames == NULL);
assert(oparg < PyTuple_GET_SIZE(consts));
kwnames = GETITEM(consts, oparg);
Expand Down Expand Up @@ -3252,8 +3236,7 @@ dummy_func(
PEEK(oparg) = top;
}

// stack effect: ( -- )
inst(EXTENDED_ARG) {
inst(EXTENDED_ARG, (--)) {
assert(oparg);
assert(cframe.use_tracing == 0);
opcode = _Py_OPCODE(*next_instr);
Expand All @@ -3262,8 +3245,7 @@ dummy_func(
DISPATCH_GOTO();
}

// stack effect: ( -- )
inst(CACHE) {
inst(CACHE, (--)) {
Py_UNREACHABLE();
}

Expand Down
48 changes: 25 additions & 23 deletions Python/generated_cases.c.h
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28 changes: 14 additions & 14 deletions Python/opcode_metadata.h
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Original file line number Diff line number Diff line change
Expand Up @@ -245,9 +245,9 @@ _PyOpcode_num_popped(int opcode, int oparg) {
case JUMP_IF_TRUE_OR_POP:
return -1;
case JUMP_BACKWARD_NO_INTERRUPT:
return -1;
return 0;
case GET_LEN:
return -1;
return 1;
case MATCH_CLASS:
return 3;
case MATCH_MAPPING:
Expand All @@ -257,7 +257,7 @@ _PyOpcode_num_popped(int opcode, int oparg) {
case MATCH_KEYS:
return 2;
case GET_ITER:
return -1;
return 1;
case GET_YIELD_FROM_ITER:
return -1;
case FOR_ITER:
Expand All @@ -273,7 +273,7 @@ _PyOpcode_num_popped(int opcode, int oparg) {
case BEFORE_ASYNC_WITH:
return -1;
case BEFORE_WITH:
return -1;
return 1;
case WITH_EXCEPT_START:
return 4;
case PUSH_EXC_INFO:
Expand All @@ -287,7 +287,7 @@ _PyOpcode_num_popped(int opcode, int oparg) {
case CALL_BOUND_METHOD_EXACT_ARGS:
return -1;
case KW_NAMES:
return -1;
return 0;
case CALL:
return -1;
case CALL_PY_EXACT_ARGS:
Expand Down Expand Up @@ -339,9 +339,9 @@ _PyOpcode_num_popped(int opcode, int oparg) {
case SWAP:
return -1;
case EXTENDED_ARG:
return -1;
return 0;
case CACHE:
return -1;
return 0;
default:
Py_UNREACHABLE();
}
Expand Down Expand Up @@ -591,9 +591,9 @@ _PyOpcode_num_pushed(int opcode, int oparg) {
case JUMP_IF_TRUE_OR_POP:
return -1;
case JUMP_BACKWARD_NO_INTERRUPT:
return -1;
return 0;
case GET_LEN:
return -1;
return 2;
case MATCH_CLASS:
return 1;
case MATCH_MAPPING:
Expand All @@ -603,7 +603,7 @@ _PyOpcode_num_pushed(int opcode, int oparg) {
case MATCH_KEYS:
return 3;
case GET_ITER:
return -1;
return 1;
case GET_YIELD_FROM_ITER:
return -1;
case FOR_ITER:
Expand All @@ -619,7 +619,7 @@ _PyOpcode_num_pushed(int opcode, int oparg) {
case BEFORE_ASYNC_WITH:
return -1;
case BEFORE_WITH:
return -1;
return 2;
case WITH_EXCEPT_START:
return 5;
case PUSH_EXC_INFO:
Expand All @@ -633,7 +633,7 @@ _PyOpcode_num_pushed(int opcode, int oparg) {
case CALL_BOUND_METHOD_EXACT_ARGS:
return -1;
case KW_NAMES:
return -1;
return 0;
case CALL:
return -1;
case CALL_PY_EXACT_ARGS:
Expand Down Expand Up @@ -685,9 +685,9 @@ _PyOpcode_num_pushed(int opcode, int oparg) {
case SWAP:
return -1;
case EXTENDED_ARG:
return -1;
return 0;
case CACHE:
return -1;
return 0;
default:
Py_UNREACHABLE();
}
Expand Down