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gh-132775: Revert "gh-132775: Add _PyCode_VerifyStateless() (gh-133221)" (#133497)

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Petr Viktorin 2025-05-06 12:09:41 +02:00 • committed by GitHub
parent fd37f1a8ad
commit 3c73cf51df
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8 changed files with 37 additions and 362 deletions
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172
Objects/codeobject.c
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@ -1955,134 +1955,12 @@ finally:
}
int
_PyCode_CheckNoInternalState(PyCodeObject *co, const char **p_errmsg)
{
const char *errmsg = NULL;
if (_PyCode_HAS_EXECUTORS(co) || _PyCode_HAS_INSTRUMENTATION(co)) {
errmsg = "only basic code objects are supported";
}
else if (co->_co_monitoring != NULL) {
errmsg = "only basic code objects are supported";
}
else if (co->co_extra != NULL) {
errmsg = "only basic code objects are supported";
}
if (errmsg != NULL) {
if (p_errmsg != NULL) {
*p_errmsg = errmsg;
}
return 0;
}
return 1;
}
int
_PyCode_CheckNoExternalState(PyCodeObject *co, _PyCode_var_counts_t *counts,
const char **p_errmsg)
{
const char *errmsg = NULL;
assert(counts->locals.hidden.total == 0);
if (counts->numfree > 0) { // It's a closure.
errmsg = "closures not supported";
}
else if (counts->unbound.globals.numglobal > 0) {
errmsg = "globals not supported";
}
else if (counts->unbound.globals.numbuiltin > 0
&& counts->unbound.globals.numunknown > 0)
{
errmsg = "globals not supported";
}
// Otherwise we don't check counts.unbound.globals.numunknown since we can't
// distinguish beween globals and builtins here.
if (errmsg != NULL) {
if (p_errmsg != NULL) {
*p_errmsg = errmsg;
}
return 0;
}
return 1;
}
int
_PyCode_VerifyStateless(PyThreadState *tstate,
PyCodeObject *co, PyObject *globalnames,
PyObject *globalsns, PyObject *builtinsns)
{
const char *errmsg;
_PyCode_var_counts_t counts = {0};
_PyCode_GetVarCounts(co, &counts);
if (_PyCode_SetUnboundVarCounts(
tstate, co, &counts, globalnames, NULL,
globalsns, builtinsns) < 0)
{
return -1;
}
// We may consider relaxing the internal state constraints
// if it becomes a problem.
if (!_PyCode_CheckNoInternalState(co, &errmsg)) {
_PyErr_SetString(tstate, PyExc_ValueError, errmsg);
return -1;
}
if (builtinsns != NULL) {
// Make sure the next check will fail for globals,
// even if there aren't any builtins.
counts.unbound.globals.numbuiltin += 1;
}
if (!_PyCode_CheckNoExternalState(co, &counts, &errmsg)) {
_PyErr_SetString(tstate, PyExc_ValueError, errmsg);
return -1;
}
// Note that we don't check co->co_flags & CO_NESTED for anything here.
return 0;
}
int
_PyCode_CheckPureFunction(PyCodeObject *co, const char **p_errmsg)
{
const char *errmsg = NULL;
if (co->co_flags & CO_GENERATOR) {
errmsg = "generators not supported";
}
else if (co->co_flags & CO_COROUTINE) {
errmsg = "coroutines not supported";
}
else if (co->co_flags & CO_ITERABLE_COROUTINE) {
errmsg = "coroutines not supported";
}
else if (co->co_flags & CO_ASYNC_GENERATOR) {
errmsg = "generators not supported";
}
if (errmsg != NULL) {
if (p_errmsg != NULL) {
*p_errmsg = errmsg;
}
return 0;
}
return 1;
}
/* Here "value" means a non-None value, since a bare return is identical
* to returning None explicitly. Likewise a missing return statement
* at the end of the function is turned into "return None". */
static int
code_returns_only_none(PyCodeObject *co)
{
if (!_PyCode_CheckPureFunction(co, NULL)) {
return 0;
}
int len = (int)Py_SIZE(co);
assert(len > 0);
// The last instruction either returns or raises. We can take advantage
// of that for a quick exit.
_Py_CODEUNIT final = _Py_GetBaseCodeUnit(co, len-1);
// Look up None in co_consts.
Py_ssize_t nconsts = PyTuple_Size(co->co_consts);
int none_index = 0;
@ -2093,42 +1971,26 @@ code_returns_only_none(PyCodeObject *co)
}
if (none_index == nconsts) {
// None wasn't there, which means there was no implicit return,
// "return", or "return None".
// That means there must be
// an explicit return (non-None), or it only raises.
if (IS_RETURN_OPCODE(final.op.code)) {
// It was an explicit return (non-None).
return 0;
}
// It must end with a raise then. We still have to walk the
// bytecode to see if there's any explicit return (non-None).
assert(IS_RAISE_OPCODE(final.op.code));
for (int i = 0; i < len; i += _PyInstruction_GetLength(co, i)) {
_Py_CODEUNIT inst = _Py_GetBaseCodeUnit(co, i);
if (IS_RETURN_OPCODE(inst.op.code)) {
// We alraedy know it isn't returning None.
return 0;
}
}
// It must only raise.
// "return", or "return None". That means there must be
// an explicit return (non-None).
return 0;
}
else {
// Walk the bytecode, looking for RETURN_VALUE.
for (int i = 0; i < len; i += _PyInstruction_GetLength(co, i)) {
_Py_CODEUNIT inst = _Py_GetBaseCodeUnit(co, i);
if (IS_RETURN_OPCODE(inst.op.code)) {
assert(i != 0);
// Ignore it if it returns None.
_Py_CODEUNIT prev = _Py_GetBaseCodeUnit(co, i-1);
if (prev.op.code == LOAD_CONST) {
// We don't worry about EXTENDED_ARG for now.
if (prev.op.arg == none_index) {
continue;
}
// Walk the bytecode, looking for RETURN_VALUE.
Py_ssize_t len = Py_SIZE(co);
for (int i = 0; i < len; i += _PyInstruction_GetLength(co, i)) {
_Py_CODEUNIT inst = _Py_GetBaseCodeUnit(co, i);
if (IS_RETURN_OPCODE(inst.op.code)) {
assert(i != 0);
// Ignore it if it returns None.
_Py_CODEUNIT prev = _Py_GetBaseCodeUnit(co, i-1);
if (prev.op.code == LOAD_CONST) {
// We don't worry about EXTENDED_ARG for now.
if (prev.op.arg == none_index) {
continue;
}
return 0;
}
return 0;
}
}
return 1;