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gh-130704: Strength reduce LOAD_FAST{_LOAD_FAST} (#130708)

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Optimize `LOAD_FAST` opcodes into faster versions that load borrowed references onto the operand stack when we can prove that the lifetime of the local outlives the lifetime of the temporary that is loaded onto the stack.
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mpage 2025-04-01 10:18:42 -07:00 • committed by GitHub
parent e9556e1004
commit 053c285f6b
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GPG key ID: B5690EEEBB952194
35 changed files with 1282 additions and 345 deletions
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28
Python/bytecodes.c
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@ -270,6 +270,11 @@ dummy_func(
value = PyStackRef_DUP(GETLOCAL(oparg));
}
replicate(8) pure inst (LOAD_FAST_BORROW, (-- value)) {
assert(!PyStackRef_IsNull(GETLOCAL(oparg)));
value = PyStackRef_Borrow(GETLOCAL(oparg));
}
inst(LOAD_FAST_AND_CLEAR, (-- value)) {
value = GETLOCAL(oparg);
GETLOCAL(oparg) = PyStackRef_NULL;
@ -282,6 +287,13 @@ dummy_func(
value2 = PyStackRef_DUP(GETLOCAL(oparg2));
}
inst(LOAD_FAST_BORROW_LOAD_FAST_BORROW, ( -- value1, value2)) {
uint32_t oparg1 = oparg >> 4;
uint32_t oparg2 = oparg & 15;
value1 = PyStackRef_Borrow(GETLOCAL(oparg1));
value2 = PyStackRef_Borrow(GETLOCAL(oparg2));
}
family(LOAD_CONST, 0) = {
LOAD_CONST_MORTAL,
LOAD_CONST_IMMORTAL,
@ -741,9 +753,8 @@ dummy_func(
// At the end we just skip over the STORE_FAST.
op(_BINARY_OP_INPLACE_ADD_UNICODE, (left, right --)) {
PyObject *left_o = PyStackRef_AsPyObjectBorrow(left);
PyObject *right_o = PyStackRef_AsPyObjectSteal(right);
assert(PyUnicode_CheckExact(left_o));
assert(PyUnicode_CheckExact(right_o));
assert(PyUnicode_CheckExact(PyStackRef_AsPyObjectBorrow(right)));
int next_oparg;
#if TIER_ONE
@ -767,10 +778,11 @@ dummy_func(
* only the locals reference, so PyUnicode_Append knows
* that the string is safe to mutate.
*/
assert(Py_REFCNT(left_o) >= 2);
assert(Py_REFCNT(left_o) >= 2 || !PyStackRef_IsHeapSafe(left));
PyStackRef_CLOSE_SPECIALIZED(left, _PyUnicode_ExactDealloc);
DEAD(left);
PyObject *temp = PyStackRef_AsPyObjectSteal(*target_local);
PyObject *right_o = PyStackRef_AsPyObjectSteal(right);
PyUnicode_Append(&temp, right_o);
*target_local = PyStackRef_FromPyObjectSteal(temp);
Py_DECREF(right_o);
@ -1110,8 +1122,7 @@ dummy_func(
// is pushed to a different frame, the callers' frame.
inst(RETURN_VALUE, (retval -- res)) {
assert(frame->owner != FRAME_OWNED_BY_INTERPRETER);
_PyStackRef temp = retval;
assert(PyStackRef_IsHeapSafe(temp));
_PyStackRef temp = PyStackRef_MakeHeapSafe(retval);
DEAD(retval);
SAVE_STACK();
assert(EMPTY());
@ -1206,7 +1217,6 @@ dummy_func(
op(_SEND, (receiver, v -- receiver, retval)) {
PyObject *receiver_o = PyStackRef_AsPyObjectBorrow(receiver);
PyObject *retval_o;
assert(frame->owner != FRAME_OWNED_BY_INTERPRETER);
if ((tstate->interp->eval_frame == NULL) &&
@ -1216,7 +1226,7 @@ dummy_func(
PyGenObject *gen = (PyGenObject *)receiver_o;
_PyInterpreterFrame *gen_frame = &gen->gi_iframe;
STACK_SHRINK(1);
_PyFrame_StackPush(gen_frame, v);
_PyFrame_StackPush(gen_frame, PyStackRef_MakeHeapSafe(v));
gen->gi_frame_state = FRAME_EXECUTING;
gen->gi_exc_state.previous_item = tstate->exc_info;
tstate->exc_info = &gen->gi_exc_state;
@ -1261,7 +1271,7 @@ dummy_func(
DEOPT_IF(gen->gi_frame_state >= FRAME_EXECUTING);
STAT_INC(SEND, hit);
gen_frame = &gen->gi_iframe;
_PyFrame_StackPush(gen_frame, v);
_PyFrame_StackPush(gen_frame, PyStackRef_MakeHeapSafe(v));
DEAD(v);
gen->gi_frame_state = FRAME_EXECUTING;
gen->gi_exc_state.previous_item = tstate->exc_info;
@ -1308,7 +1318,7 @@ dummy_func(
#endif
RELOAD_STACK();
LOAD_IP(1 + INLINE_CACHE_ENTRIES_SEND);
value = temp;
value = PyStackRef_MakeHeapSafe(temp);
LLTRACE_RESUME_FRAME();
}