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GH-128563: Move some labels, to simplify implementing tailcalling int…
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…erpreter. (GH-129525)
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markshannon authored Jan 31, 2025
1 parent 9ba281d commit 54f74b8
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Showing 5 changed files with 86 additions and 51 deletions.
33 changes: 29 additions & 4 deletions Python/bytecodes.c
Original file line number Diff line number Diff line change
Expand Up @@ -5303,14 +5303,40 @@ dummy_func(
tstate->c_recursion_remaining += PY_EVAL_C_STACK_UNITS;
return NULL;
}
goto resume_with_error;
next_instr = frame->instr_ptr;
stack_pointer = _PyFrame_GetStackPointer(frame);
goto error;
}

label(resume_with_error) {
label(start_frame) {
if (_Py_EnterRecursivePy(tstate)) {
goto exit_unwind;
}
next_instr = frame->instr_ptr;
stack_pointer = _PyFrame_GetStackPointer(frame);
goto error;

#ifdef LLTRACE
{
int lltrace = maybe_lltrace_resume_frame(frame, GLOBALS());
frame->lltrace = lltrace;
if (lltrace < 0) {
goto exit_unwind;
}
}
#endif

#ifdef Py_DEBUG
/* _PyEval_EvalFrameDefault() must not be called with an exception set,
because it can clear it (directly or indirectly) and so the
caller loses its exception */
assert(!_PyErr_Occurred(tstate));
#endif

DISPATCH();
}



// END BYTECODES //

}
Expand All @@ -5320,7 +5346,6 @@ dummy_func(
exit_unwind:
handle_eval_breaker:
resume_frame:
resume_with_error:
start_frame:
unbound_local_error:
;
Expand Down
70 changes: 29 additions & 41 deletions Python/ceval.c
Original file line number Diff line number Diff line change
Expand Up @@ -792,6 +792,11 @@ _PyEval_EvalFrameDefault(PyThreadState *tstate, _PyInterpreterFrame *frame, int
return NULL;
}

/* Local "register" variables.
* These are cached values from the frame and code object. */
_Py_CODEUNIT *next_instr;
_PyStackRef *stack_pointer;

#if defined(Py_DEBUG) && !defined(Py_STACKREF_DEBUG)
/* Set these to invalid but identifiable values for debugging. */
entry_frame.f_funcobj = (_PyStackRef){.bits = 0xaaa0};
Expand Down Expand Up @@ -819,67 +824,36 @@ _PyEval_EvalFrameDefault(PyThreadState *tstate, _PyInterpreterFrame *frame, int
/* support for generator.throw() */
if (throwflag) {
if (_Py_EnterRecursivePy(tstate)) {
goto exit_unwind;
goto early_exit;
}
/* Because this avoids the RESUME,
* we need to update instrumentation */
#ifdef Py_GIL_DISABLED
/* Load thread-local bytecode */
if (frame->tlbc_index != ((_PyThreadStateImpl *)tstate)->tlbc_index) {
_Py_CODEUNIT *bytecode =
_PyEval_GetExecutableCode(tstate, _PyFrame_GetCode(frame));
if (bytecode == NULL) {
goto exit_unwind;
goto early_exit;
}
ptrdiff_t off = frame->instr_ptr - _PyFrame_GetBytecode(frame);
frame->tlbc_index = ((_PyThreadStateImpl *)tstate)->tlbc_index;
frame->instr_ptr = bytecode + off;
}
#endif
/* Because this avoids the RESUME, we need to update instrumentation */
_Py_Instrument(_PyFrame_GetCode(frame), tstate->interp);
monitor_throw(tstate, frame, frame->instr_ptr);
/* TO DO -- Monitor throw entry. */
goto resume_with_error;
next_instr = frame->instr_ptr;
stack_pointer = _PyFrame_GetStackPointer(frame);
monitor_throw(tstate, frame, next_instr);
goto error;
}

/* Local "register" variables.
* These are cached values from the frame and code object. */
_Py_CODEUNIT *next_instr;
_PyStackRef *stack_pointer;

#if defined(_Py_TIER2) && !defined(_Py_JIT)
/* Tier 2 interpreter state */
_PyExecutorObject *current_executor = NULL;
const _PyUOpInstruction *next_uop = NULL;
#endif

start_frame:
if (_Py_EnterRecursivePy(tstate)) {
goto exit_unwind;
}

next_instr = frame->instr_ptr;
resume_frame:
stack_pointer = _PyFrame_GetStackPointer(frame);

#ifdef LLTRACE
{
int lltrace = maybe_lltrace_resume_frame(frame, GLOBALS());
frame->lltrace = lltrace;
if (lltrace < 0) {
goto exit_unwind;
}
}
#endif

#ifdef Py_DEBUG
/* _PyEval_EvalFrameDefault() must not be called with an exception set,
because it can clear it (directly or indirectly) and so the
caller loses its exception */
assert(!_PyErr_Occurred(tstate));
#endif

DISPATCH();
goto start_frame;

#include "generated_cases.c.h"

Expand Down Expand Up @@ -983,10 +957,10 @@ _PyEval_EvalFrameDefault(PyThreadState *tstate, _PyInterpreterFrame *frame, int
OPT_HIST(trace_uop_execution_counter, trace_run_length_hist);
assert(next_uop[-1].format == UOP_FORMAT_TARGET);
frame->return_offset = 0; // Don't leave this random
_PyFrame_SetStackPointer(frame, stack_pointer);
Py_DECREF(current_executor);
tstate->previous_executor = NULL;
goto resume_with_error;
next_instr = frame->instr_ptr;
goto error;

jump_to_jump_target:
assert(next_uop[-1].format == UOP_FORMAT_JUMP);
Expand Down Expand Up @@ -1018,6 +992,20 @@ _PyEval_EvalFrameDefault(PyThreadState *tstate, _PyInterpreterFrame *frame, int

#endif // _Py_TIER2

early_exit:
assert(_PyErr_Occurred(tstate));
_Py_LeaveRecursiveCallPy(tstate);
assert(frame->owner != FRAME_OWNED_BY_INTERPRETER);
// GH-99729: We need to unlink the frame *before* clearing it:
_PyInterpreterFrame *dying = frame;
frame = tstate->current_frame = dying->previous;
_PyEval_FrameClearAndPop(tstate, dying);
frame->return_offset = 0;
assert(frame->owner == FRAME_OWNED_BY_INTERPRETER);
/* Restore previous frame and exit */
tstate->current_frame = frame->previous;
tstate->c_recursion_remaining += PY_EVAL_C_STACK_UNITS;
return NULL;
}

#if defined(__GNUC__)
Expand Down
4 changes: 3 additions & 1 deletion Python/ceval_macros.h
Original file line number Diff line number Diff line change
Expand Up @@ -381,7 +381,9 @@ do { \
tstate->previous_executor = NULL; \
frame = tstate->current_frame; \
if (next_instr == NULL) { \
goto resume_with_error; \
next_instr = frame->instr_ptr; \
stack_pointer = _PyFrame_GetStackPointer(frame); \
goto error; \
} \
stack_pointer = _PyFrame_GetStackPointer(frame); \
DISPATCH(); \
Expand Down
28 changes: 25 additions & 3 deletions Python/generated_cases.c.h

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2 changes: 0 additions & 2 deletions Tools/cases_generator/analyzer.py
Original file line number Diff line number Diff line change
Expand Up @@ -511,7 +511,6 @@ def has_error_with_pop(op: parser.InstDef) -> bool:
variable_used(op, "ERROR_IF")
or variable_used(op, "pop_1_error")
or variable_used(op, "exception_unwind")
or variable_used(op, "resume_with_error")
)


Expand All @@ -520,7 +519,6 @@ def has_error_without_pop(op: parser.InstDef) -> bool:
variable_used(op, "ERROR_NO_POP")
or variable_used(op, "pop_1_error")
or variable_used(op, "exception_unwind")
or variable_used(op, "resume_with_error")
)


Expand Down

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