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bpo-46841: Don't scan backwards in bytecode (GH-31901)

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Mark Shannon 2022-03-16 00:08:37 +00:00 • committed by GitHub
parent a4674f0194
commit 49e1e1e1bd
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2 changed files with 12 additions and 15 deletions
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20
Python/ceval.c
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@ -1565,16 +1565,6 @@ trace_function_exit(PyThreadState *tstate, _PyInterpreterFrame *frame, PyObject
return 0;
}
static int
skip_backwards_over_extended_args(PyCodeObject *code, int offset)
{
_Py_CODEUNIT *instrs = (_Py_CODEUNIT *)PyBytes_AS_STRING(code->co_code);
while (offset > 0 && _Py_OPCODE(instrs[offset-1]) == EXTENDED_ARG) {
offset--;
}
return offset;
}
static _PyInterpreterFrame *
pop_frame(PyThreadState *tstate, _PyInterpreterFrame *frame)
{
@ -5445,7 +5435,7 @@ handle_eval_breaker:
#endif
{
if (tstate->tracing == 0) {
int instr_prev = skip_backwards_over_extended_args(frame->f_code, frame->f_lasti);
int instr_prev = frame->f_lasti;
frame->f_lasti = INSTR_OFFSET();
TRACING_NEXTOPARG();
if (opcode == RESUME) {
@ -6737,9 +6727,13 @@ maybe_call_line_trace(Py_tracefunc func, PyObject *obj,
then call the trace function if we're tracing source lines.
*/
initialize_trace_info(&tstate->trace_info, frame);
_Py_CODEUNIT prev = ((_Py_CODEUNIT *)PyBytes_AS_STRING(frame->f_code->co_code))[instr_prev];
int entry_point = 0;
_Py_CODEUNIT *code = (_Py_CODEUNIT *)PyBytes_AS_STRING(frame->f_code->co_code);
while (_Py_OPCODE(code[entry_point]) != RESUME) {
entry_point++;
}
int lastline;
if (_Py_OPCODE(prev) == RESUME && _Py_OPARG(prev) == 0) {
if (instr_prev <= entry_point) {
lastline = -1;
}
else {