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gvanrossumbrandtbucher
gvanrossum
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brandtbucher
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GH-98831: Remove all remaining DISPATCH() calls from bytecodes.c (#99271)
Also mark those opcodes that have no stack effect as such. Co-authored-by: Brandt Bucher <[email protected]>
1 parent 00ee6d5 commit 694cdb2

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2 files changed

+175
-169
lines changed

2 files changed

+175
-169
lines changed

‎Python/bytecodes.c

+88-94
Original file line numberDiff line numberDiff line change
@@ -68,7 +68,6 @@ do { \
6868
#define JUMPBY(offset) ((void)0)
6969
#define GO_TO_INSTRUCTION(instname) ((void)0)
7070
#define DISPATCH_SAME_OPARG() ((void)0)
71-
#define DISPATCH() ((void)0)
7271

7372
#define inst(name, ...) case name:
7473
#define super(name) static int SUPER_##name
@@ -104,10 +103,6 @@ dummy_func(
104103
{
105104
switch (opcode) {
106105

107-
/* BEWARE!
108-
It is essential that any operation that fails must goto error
109-
and that all operation that succeed call DISPATCH() ! */
110-
111106
// BEGIN BYTECODES //
112107
inst(NOP, (--)) {
113108
}
@@ -152,16 +147,14 @@ dummy_func(
152147
super(LOAD_FAST__LOAD_CONST) = LOAD_FAST + LOAD_CONST;
153148
super(STORE_FAST__LOAD_FAST) = STORE_FAST + LOAD_FAST;
154149
super(STORE_FAST__STORE_FAST) = STORE_FAST + STORE_FAST;
155-
super (LOAD_CONST__LOAD_FAST) = LOAD_CONST + LOAD_FAST;
150+
super(LOAD_CONST__LOAD_FAST) = LOAD_CONST + LOAD_FAST;
156151

157152
inst(POP_TOP, (value --)) {
158153
Py_DECREF(value);
159154
}
160155

161-
// stack effect: ( -- __0)
162-
inst(PUSH_NULL) {
163-
/* Use BASIC_PUSH as NULL is not a valid object pointer */
164-
BASIC_PUSH(NULL);
156+
inst(PUSH_NULL, (-- res)) {
157+
res = NULL;
165158
}
166159

167160
inst(END_FOR, (value1, value2 --)) {
@@ -816,11 +809,12 @@ dummy_func(
816809
Py_DECREF(receiver);
817810
SET_TOP(retval);
818811
JUMPBY(oparg);
819-
DISPATCH();
820812
}
821-
assert(gen_status == PYGEN_NEXT);
822-
assert(retval != NULL);
823-
PUSH(retval);
813+
else {
814+
assert(gen_status == PYGEN_NEXT);
815+
assert(retval != NULL);
816+
PUSH(retval);
817+
}
824818
}
825819

826820
// stack effect: ( -- )
@@ -913,7 +907,6 @@ dummy_func(
913907
if (PyErr_GivenExceptionMatches(val, PyExc_StopAsyncIteration)) {
914908
Py_DECREF(val);
915909
Py_DECREF(POP());
916-
DISPATCH();
917910
}
918911
else {
919912
PyObject *exc = Py_NewRef(PyExceptionInstance_Class(val));
@@ -935,12 +928,13 @@ dummy_func(
935928
Py_DECREF(POP()); // The last sent value.
936929
Py_DECREF(POP()); // The delegated sub-iterator.
937930
PUSH(value);
938-
DISPATCH();
939931
}
940-
PyObject *exc_type = Py_NewRef(Py_TYPE(exc_value));
941-
PyObject *exc_traceback = PyException_GetTraceback(exc_value);
942-
_PyErr_Restore(tstate, exc_type, Py_NewRef(exc_value), exc_traceback);
943-
goto exception_unwind;
932+
else {
933+
PyObject *exc_type = Py_NewRef(Py_TYPE(exc_value));
934+
PyObject *exc_traceback = PyException_GetTraceback(exc_value);
935+
_PyErr_Restore(tstate, exc_type, Py_NewRef(exc_value), exc_traceback);
936+
goto exception_unwind;
937+
}
944938
}
945939

946940
inst(STOPITERATION_ERROR) {
@@ -982,7 +976,6 @@ dummy_func(
982976
PyException_SetContext(error, exc);
983977
Py_DECREF(message);
984978
}
985-
DISPATCH();
986979
}
987980

988981

@@ -1040,8 +1033,7 @@ dummy_func(
10401033
goto error;
10411034
}
10421035

1043-
// stack effect: ( -- )
1044-
inst(DELETE_NAME) {
1036+
inst(DELETE_NAME, (--)) {
10451037
PyObject *name = GETITEM(names, oparg);
10461038
PyObject *ns = LOCALS();
10471039
int err;
@@ -1051,6 +1043,7 @@ dummy_func(
10511043
goto error;
10521044
}
10531045
err = PyObject_DelItem(ns, name);
1046+
// Can't use ERROR_IF here.
10541047
if (err != 0) {
10551048
format_exc_check_arg(tstate, PyExc_NameError,
10561049
NAME_ERROR_MSG,
@@ -1190,11 +1183,11 @@ dummy_func(
11901183
goto error;
11911184
}
11921185

1193-
// stack effect: ( -- )
1194-
inst(DELETE_GLOBAL) {
1186+
inst(DELETE_GLOBAL, (--)) {
11951187
PyObject *name = GETITEM(names, oparg);
11961188
int err;
11971189
err = PyDict_DelItem(GLOBALS(), name);
1190+
// Can't use ERROR_IF here.
11981191
if (err != 0) {
11991192
if (_PyErr_ExceptionMatches(tstate, PyExc_KeyError)) {
12001193
format_exc_check_arg(tstate, PyExc_NameError,
@@ -1374,18 +1367,13 @@ dummy_func(
13741367
SET_TOP(Py_NewRef(res));
13751368
}
13761369

1377-
// stack effect: ( -- )
1378-
inst(DELETE_FAST) {
1370+
inst(DELETE_FAST, (--)) {
13791371
PyObject *v = GETLOCAL(oparg);
1380-
if (v != NULL) {
1381-
SETLOCAL(oparg, NULL);
1382-
DISPATCH();
1383-
}
1384-
goto unbound_local_error;
1372+
ERROR_IF(v == NULL, unbound_local_error);
1373+
SETLOCAL(oparg, NULL);
13851374
}
13861375

1387-
// stack effect: ( -- )
1388-
inst(MAKE_CELL) {
1376+
inst(MAKE_CELL, (--)) {
13891377
// "initial" is probably NULL but not if it's an arg (or set
13901378
// via PyFrame_LocalsToFast() before MAKE_CELL has run).
13911379
PyObject *initial = GETLOCAL(oparg);
@@ -1396,17 +1384,17 @@ dummy_func(
13961384
SETLOCAL(oparg, cell);
13971385
}
13981386

1399-
// stack effect: ( -- )
1400-
inst(DELETE_DEREF) {
1387+
inst(DELETE_DEREF, (--)) {
14011388
PyObject *cell = GETLOCAL(oparg);
14021389
PyObject *oldobj = PyCell_GET(cell);
1403-
if (oldobj != NULL) {
1404-
PyCell_SET(cell, NULL);
1405-
Py_DECREF(oldobj);
1406-
DISPATCH();
1390+
// Can't use ERROR_IF here.
1391+
// Fortunately we don't need its superpower.
1392+
if (oldobj == NULL) {
1393+
format_exc_unbound(tstate, frame->f_code, oparg);
1394+
goto error;
14071395
}
1408-
format_exc_unbound(tstate, frame->f_code, oparg);
1409-
goto error;
1396+
PyCell_SET(cell, NULL);
1397+
Py_DECREF(oldobj);
14101398
}
14111399

14121400
// stack effect: ( -- __0)
@@ -1769,15 +1757,15 @@ dummy_func(
17691757
Py_DECREF(owner);
17701758
PUSH(meth);
17711759
}
1772-
JUMPBY(INLINE_CACHE_ENTRIES_LOAD_ATTR);
1773-
DISPATCH();
17741760
}
1775-
PyObject *res = PyObject_GetAttr(owner, name);
1776-
if (res == NULL) {
1777-
goto error;
1761+
else {
1762+
PyObject *res = PyObject_GetAttr(owner, name);
1763+
if (res == NULL) {
1764+
goto error;
1765+
}
1766+
Py_DECREF(owner);
1767+
SET_TOP(res);
17781768
}
1779-
Py_DECREF(owner);
1780-
SET_TOP(res);
17811769
JUMPBY(INLINE_CACHE_ENTRIES_LOAD_ATTR);
17821770
}
17831771

@@ -2435,21 +2423,23 @@ dummy_func(
24352423
if (Py_IsTrue(cond)) {
24362424
STACK_SHRINK(1);
24372425
_Py_DECREF_NO_DEALLOC(cond);
2438-
DISPATCH();
24392426
}
2440-
if (Py_IsFalse(cond)) {
2427+
else if (Py_IsFalse(cond)) {
24412428
JUMPBY(oparg);
2442-
DISPATCH();
24432429
}
2444-
err = PyObject_IsTrue(cond);
2445-
if (err > 0) {
2446-
STACK_SHRINK(1);
2447-
Py_DECREF(cond);
2430+
else {
2431+
err = PyObject_IsTrue(cond);
2432+
if (err > 0) {
2433+
STACK_SHRINK(1);
2434+
Py_DECREF(cond);
2435+
}
2436+
else if (err == 0) {
2437+
JUMPBY(oparg);
2438+
}
2439+
else {
2440+
goto error;
2441+
}
24482442
}
2449-
else if (err == 0)
2450-
JUMPBY(oparg);
2451-
else
2452-
goto error;
24532443
}
24542444

24552445
// error: JUMP_IF_TRUE_OR_POP stack effect depends on jump flag
@@ -2459,22 +2449,23 @@ dummy_func(
24592449
if (Py_IsFalse(cond)) {
24602450
STACK_SHRINK(1);
24612451
_Py_DECREF_NO_DEALLOC(cond);
2462-
DISPATCH();
2463-
}
2464-
if (Py_IsTrue(cond)) {
2465-
JUMPBY(oparg);
2466-
DISPATCH();
24672452
}
2468-
err = PyObject_IsTrue(cond);
2469-
if (err > 0) {
2453+
else if (Py_IsTrue(cond)) {
24702454
JUMPBY(oparg);
24712455
}
2472-
else if (err == 0) {
2473-
STACK_SHRINK(1);
2474-
Py_DECREF(cond);
2456+
else {
2457+
err = PyObject_IsTrue(cond);
2458+
if (err > 0) {
2459+
JUMPBY(oparg);
2460+
}
2461+
else if (err == 0) {
2462+
STACK_SHRINK(1);
2463+
Py_DECREF(cond);
2464+
}
2465+
else {
2466+
goto error;
2467+
}
24752468
}
2476-
else
2477-
goto error;
24782469
}
24792470

24802471
// stack effect: ( -- )
@@ -2615,23 +2606,24 @@ dummy_func(
26152606
if (next != NULL) {
26162607
PUSH(next);
26172608
JUMPBY(INLINE_CACHE_ENTRIES_FOR_ITER);
2618-
DISPATCH();
26192609
}
2620-
if (_PyErr_Occurred(tstate)) {
2621-
if (!_PyErr_ExceptionMatches(tstate, PyExc_StopIteration)) {
2622-
goto error;
2623-
}
2624-
else if (tstate->c_tracefunc != NULL) {
2625-
call_exc_trace(tstate->c_tracefunc, tstate->c_traceobj, tstate, frame);
2610+
else {
2611+
if (_PyErr_Occurred(tstate)) {
2612+
if (!_PyErr_ExceptionMatches(tstate, PyExc_StopIteration)) {
2613+
goto error;
2614+
}
2615+
else if (tstate->c_tracefunc != NULL) {
2616+
call_exc_trace(tstate->c_tracefunc, tstate->c_traceobj, tstate, frame);
2617+
}
2618+
_PyErr_Clear(tstate);
26262619
}
2627-
_PyErr_Clear(tstate);
2620+
/* iterator ended normally */
2621+
assert(_Py_OPCODE(next_instr[INLINE_CACHE_ENTRIES_FOR_ITER + oparg]) == END_FOR);
2622+
STACK_SHRINK(1);
2623+
Py_DECREF(iter);
2624+
/* Skip END_FOR */
2625+
JUMPBY(INLINE_CACHE_ENTRIES_FOR_ITER + oparg + 1);
26282626
}
2629-
/* iterator ended normally */
2630-
assert(_Py_OPCODE(next_instr[INLINE_CACHE_ENTRIES_FOR_ITER + oparg]) == END_FOR);
2631-
STACK_SHRINK(1);
2632-
Py_DECREF(iter);
2633-
/* Skip END_FOR */
2634-
JUMPBY(INLINE_CACHE_ENTRIES_FOR_ITER + oparg + 1);
26352627
}
26362628

26372629
// stack effect: ( -- __0)
@@ -2646,14 +2638,15 @@ dummy_func(
26462638
PyObject *next = PyList_GET_ITEM(seq, it->it_index++);
26472639
PUSH(Py_NewRef(next));
26482640
JUMPBY(INLINE_CACHE_ENTRIES_FOR_ITER);
2649-
DISPATCH();
2641+
goto end_for_iter_list; // End of this instruction
26502642
}
26512643
it->it_seq = NULL;
26522644
Py_DECREF(seq);
26532645
}
26542646
STACK_SHRINK(1);
26552647
Py_DECREF(it);
26562648
JUMPBY(INLINE_CACHE_ENTRIES_FOR_ITER + oparg + 1);
2649+
end_for_iter_list:
26572650
}
26582651

26592652
// stack effect: ( -- __0)
@@ -2668,15 +2661,16 @@ dummy_func(
26682661
STACK_SHRINK(1);
26692662
Py_DECREF(r);
26702663
JUMPBY(INLINE_CACHE_ENTRIES_FOR_ITER + oparg + 1);
2671-
DISPATCH();
26722664
}
2673-
long value = (long)(r->start +
2674-
(unsigned long)(r->index++) * r->step);
2675-
if (_PyLong_AssignValue(&GETLOCAL(_Py_OPARG(next)), value) < 0) {
2676-
goto error;
2665+
else {
2666+
long value = (long)(r->start +
2667+
(unsigned long)(r->index++) * r->step);
2668+
if (_PyLong_AssignValue(&GETLOCAL(_Py_OPARG(next)), value) < 0) {
2669+
goto error;
2670+
}
2671+
// The STORE_FAST is already done.
2672+
JUMPBY(INLINE_CACHE_ENTRIES_FOR_ITER + 1);
26772673
}
2678-
// The STORE_FAST is already done.
2679-
JUMPBY(INLINE_CACHE_ENTRIES_FOR_ITER + 1);
26802674
}
26812675

26822676
inst(FOR_ITER_GEN) {

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