gh-106529: Split FOR_ITER_RANGE into uops (#106638)

For an example of what this does for Tier 1 and Tier 2, see
https://github.com/python/cpython/issues/106529#issuecomment-1631649920
This commit is contained in:
Guido van Rossum 2023-07-12 10:23:59 -07:00 committed by GitHub
parent 7f55f58b6c
commit dd1884dc5d
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6 changed files with 146 additions and 28 deletions

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@ -40,6 +40,9 @@
#define _GUARD_GLOBALS_VERSION 318
#define _GUARD_BUILTINS_VERSION 319
#define IS_NONE 320
#define _ITER_CHECK_RANGE 321
#define _ITER_EXHAUSTED_RANGE 322
#define _ITER_NEXT_RANGE 323
#ifndef NEED_OPCODE_METADATA
extern int _PyOpcode_num_popped(int opcode, int oparg, bool jump);
@ -1319,5 +1322,8 @@ const char * const _PyOpcode_uop_name[512] = {
[318] = "_GUARD_GLOBALS_VERSION",
[319] = "_GUARD_BUILTINS_VERSION",
[320] = "IS_NONE",
[321] = "_ITER_CHECK_RANGE",
[322] = "_ITER_EXHAUSTED_RANGE",
[323] = "_ITER_NEXT_RANGE",
};
#endif // NEED_OPCODE_METADATA

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@ -2443,7 +2443,6 @@ class TestUops(unittest.TestCase):
i += 1
opt = _testinternalcapi.get_uop_optimizer()
with temporary_optimizer(opt):
testfunc(1000)
@ -2580,13 +2579,33 @@ class TestUops(unittest.TestCase):
ex = get_first_executor(testfunc)
self.assertIsNotNone(ex)
# for i, (opname, oparg) in enumerate(ex):
# print(f"{i:4d}: {opname:<20s} {oparg:4d}")
uops = {opname for opname, _ in ex}
# Since there is no JUMP_FORWARD instruction,
# look for indirect evidence: the += operator
self.assertIn("_BINARY_OP_ADD_INT", uops)
def test_for_iter_range(self):
def testfunc(n):
total = 0
for i in range(n):
total += i
return total
# import dis; dis.dis(testfunc)
opt = _testinternalcapi.get_uop_optimizer()
with temporary_optimizer(opt):
total = testfunc(10)
self.assertEqual(total, 45)
ex = get_first_executor(testfunc)
self.assertIsNotNone(ex)
# for i, (opname, oparg) in enumerate(ex):
# print(f"{i:4d}: {opname:<20s} {oparg:3d}")
uops = {opname for opname, _ in ex}
self.assertIn("_ITER_EXHAUSTED_RANGE", uops)
# Verification that the jump goes past END_FOR
# is done by manual inspection of the output
if __name__ == "__main__":
unittest.main()

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@ -2451,9 +2451,14 @@ dummy_func(
// Common case: no jump, leave it to the code generator
}
inst(FOR_ITER_RANGE, (unused/1, iter -- iter, next)) {
op(_ITER_CHECK_RANGE, (iter -- iter)) {
_PyRangeIterObject *r = (_PyRangeIterObject *)iter;
DEOPT_IF(Py_TYPE(r) != &PyRangeIter_Type, FOR_ITER);
}
op(_ITER_JUMP_RANGE, (iter -- iter)) {
_PyRangeIterObject *r = (_PyRangeIterObject *)iter;
assert(Py_TYPE(r) == &PyRangeIter_Type);
STAT_INC(FOR_ITER, hit);
if (r->len <= 0) {
STACK_SHRINK(1);
@ -2463,15 +2468,29 @@ dummy_func(
JUMPBY(oparg + 1);
DISPATCH();
}
}
// Only used by Tier 2
op(_ITER_EXHAUSTED_RANGE, (iter -- iter, exhausted)) {
_PyRangeIterObject *r = (_PyRangeIterObject *)iter;
assert(Py_TYPE(r) == &PyRangeIter_Type);
exhausted = r->len <= 0 ? Py_True : Py_False;
}
op(_ITER_NEXT_RANGE, (iter -- iter, next)) {
_PyRangeIterObject *r = (_PyRangeIterObject *)iter;
assert(Py_TYPE(r) == &PyRangeIter_Type);
assert(r->len > 0);
long value = r->start;
r->start = value + r->step;
r->len--;
next = PyLong_FromLong(value);
if (next == NULL) {
goto error;
}
ERROR_IF(next == NULL, error);
}
macro(FOR_ITER_RANGE) =
unused/1 + _ITER_CHECK_RANGE + _ITER_JUMP_RANGE + _ITER_NEXT_RANGE;
inst(FOR_ITER_GEN, (unused/1, iter -- iter, unused)) {
DEOPT_IF(tstate->interp->eval_frame, FOR_ITER);
PyGenObject *gen = (PyGenObject *)iter;

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@ -1720,6 +1720,40 @@
break;
}
case _ITER_CHECK_RANGE: {
PyObject *iter = stack_pointer[-1];
_PyRangeIterObject *r = (_PyRangeIterObject *)iter;
DEOPT_IF(Py_TYPE(r) != &PyRangeIter_Type, FOR_ITER);
break;
}
case _ITER_EXHAUSTED_RANGE: {
PyObject *iter = stack_pointer[-1];
PyObject *exhausted;
_PyRangeIterObject *r = (_PyRangeIterObject *)iter;
assert(Py_TYPE(r) == &PyRangeIter_Type);
exhausted = r->len <= 0 ? Py_True : Py_False;
STACK_GROW(1);
stack_pointer[-1] = exhausted;
break;
}
case _ITER_NEXT_RANGE: {
PyObject *iter = stack_pointer[-1];
PyObject *next;
_PyRangeIterObject *r = (_PyRangeIterObject *)iter;
assert(Py_TYPE(r) == &PyRangeIter_Type);
assert(r->len > 0);
long value = r->start;
r->start = value + r->step;
r->len--;
next = PyLong_FromLong(value);
if (next == NULL) goto error;
STACK_GROW(1);
stack_pointer[-1] = next;
break;
}
case WITH_EXCEPT_START: {
PyObject *val = stack_pointer[-1];
PyObject *lasti = stack_pointer[-3];

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@ -3092,29 +3092,47 @@
}
TARGET(FOR_ITER_RANGE) {
PyObject *iter = stack_pointer[-1];
PyObject *next;
_PyRangeIterObject *r = (_PyRangeIterObject *)iter;
DEOPT_IF(Py_TYPE(r) != &PyRangeIter_Type, FOR_ITER);
STAT_INC(FOR_ITER, hit);
if (r->len <= 0) {
STACK_SHRINK(1);
Py_DECREF(r);
SKIP_OVER(INLINE_CACHE_ENTRIES_FOR_ITER);
// Jump over END_FOR instruction.
JUMPBY(oparg + 1);
DISPATCH();
PyObject *_tmp_1;
PyObject *_tmp_2 = stack_pointer[-1];
{
PyObject *iter = _tmp_2;
_PyRangeIterObject *r = (_PyRangeIterObject *)iter;
DEOPT_IF(Py_TYPE(r) != &PyRangeIter_Type, FOR_ITER);
_tmp_2 = iter;
}
long value = r->start;
r->start = value + r->step;
r->len--;
next = PyLong_FromLong(value);
if (next == NULL) {
goto error;
{
PyObject *iter = _tmp_2;
_PyRangeIterObject *r = (_PyRangeIterObject *)iter;
assert(Py_TYPE(r) == &PyRangeIter_Type);
STAT_INC(FOR_ITER, hit);
if (r->len <= 0) {
STACK_SHRINK(1);
Py_DECREF(r);
SKIP_OVER(INLINE_CACHE_ENTRIES_FOR_ITER);
// Jump over END_FOR instruction.
JUMPBY(oparg + 1);
DISPATCH();
}
_tmp_2 = iter;
}
{
PyObject *iter = _tmp_2;
PyObject *next;
_PyRangeIterObject *r = (_PyRangeIterObject *)iter;
assert(Py_TYPE(r) == &PyRangeIter_Type);
assert(r->len > 0);
long value = r->start;
r->start = value + r->step;
r->len--;
next = PyLong_FromLong(value);
if (next == NULL) goto error;
_tmp_2 = iter;
_tmp_1 = next;
}
STACK_GROW(1);
stack_pointer[-1] = next;
next_instr += 1;
STACK_GROW(1);
stack_pointer[-1] = _tmp_1;
stack_pointer[-2] = _tmp_2;
DISPATCH();
}

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@ -479,6 +479,28 @@ translate_bytecode_to_trace(
break;
}
case FOR_ITER_RANGE:
{
// Assume jump unlikely (can a for-loop exit be likely?)
// Reserve 9 entries (4 here, 3 stub, plus SAVE_IP + EXIT_TRACE)
if (trace_length + 9 > max_length) {
DPRINTF(1, "Ran out of space for FOR_ITER_RANGE\n");
goto done;
}
_Py_CODEUNIT *target_instr = // +1 at the end skips over END_FOR
instr + 1 + _PyOpcode_Caches[_PyOpcode_Deopt[opcode]] + oparg + 1;
max_length -= 3; // Really the start of the stubs
ADD_TO_TRACE(_ITER_CHECK_RANGE, 0);
ADD_TO_TRACE(_ITER_EXHAUSTED_RANGE, 0);
ADD_TO_TRACE(_POP_JUMP_IF_TRUE, max_length);
ADD_TO_TRACE(_ITER_NEXT_RANGE, 0);
ADD_TO_STUB(max_length + 0, POP_TOP, 0);
ADD_TO_STUB(max_length + 1, SAVE_IP, INSTR_IP(target_instr, code));
ADD_TO_STUB(max_length + 2, EXIT_TRACE, 0);
break;
}
default:
{
const struct opcode_macro_expansion *expansion = &_PyOpcode_macro_expansion[opcode];
@ -574,8 +596,8 @@ done:
}
}
}
trace_length += buffer_size - max_length;
}
trace_length += buffer_size - max_length;
return trace_length;
}
else {