Skip to content

GH-96793: Specialize FOR_ITER for generators. #98772

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Merged
merged 7 commits into from
Nov 7, 2022
Merged

GH-96793: Specialize FOR_ITER for generators. #98772

Show file tree
Hide file tree
Changes from 2 commits
Commits
Show all changes
7 commits
Select commit Hold shift + click to select a range
3d229cc
Specialize FOR_ITER for generators.
markshannon Oct 27, 2022
d8e88b0
Add news
markshannon Oct 28, 2022
e16d82c
Merge branch 'main' into specialize-for-iter-gen
markshannon Nov 4, 2022
86aa1a8
Clean up after merge.
markshannon Nov 4, 2022
a677191
Add test for nested exc_info in loop.
markshannon Nov 7, 2022
8256be6
Handle exc stack.
markshannon Nov 7, 2022
8fb80ca
Use new API for current exception
markshannon Nov 7, 2022
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
2 changes: 1 addition & 1 deletion Include/internal/pycore_code.h
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -250,7 +250,7 @@ extern void _Py_Specialize_CompareOp(PyObject *lhs, PyObject *rhs,
_Py_CODEUNIT *instr, int oparg);
extern void _Py_Specialize_UnpackSequence(PyObject *seq, _Py_CODEUNIT *instr,
int oparg);
extern void _Py_Specialize_ForIter(PyObject *iter, _Py_CODEUNIT *instr);
extern void _Py_Specialize_ForIter(PyObject *iter, _Py_CODEUNIT *instr, int oparg);

/* Deallocator function for static codeobjects used in deepfreeze.py */
extern void _PyStaticCode_Dealloc(PyCodeObject *co);
Expand Down
2 changes: 2 additions & 0 deletions Include/internal/pycore_frame.h
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -61,6 +61,7 @@ typedef struct _PyInterpreterFrame {
// over, or (in the case of a newly-created frame) a totally invalid value:
_Py_CODEUNIT *prev_instr;
int stacktop; /* Offset of TOS from localsplus */
uint16_t yield_offset;
bool is_entry; // Whether this is the "root" frame for the current _PyCFrame.
char owner;
/* Locals and stack */
Expand Down Expand Up @@ -110,6 +111,7 @@ _PyFrame_InitializeSpecials(
frame->frame_obj = NULL;
frame->prev_instr = _PyCode_CODE(code) - 1;
frame->is_entry = false;
frame->yield_offset = 0;
Copy link
Member

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Why is this called "yield_offset", is it not the relative offset to jump by when the generator is exhausted? (the same as the arg to FOR_ITER?)

Copy link
Member Author

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Because it's the offset for YIELD_VALUE to return to relative to RETURN_VALUE
https://github.com/python/cpython/pull/98772/files#diff-c22186367cbe20233e843261998dc027ae5f1f8c0d2e778abfa454ae74cc59deR2087

frame->owner = FRAME_OWNED_BY_THREAD;
}

Expand Down
24 changes: 12 additions & 12 deletions Include/internal/pycore_opcode.h
View file
Open in desktop

Some generated files are not rendered by default. Learn more about how customized files appear on GitHub.

67 changes: 34 additions & 33 deletions Include/opcode.h
View file
Open in desktop

Some generated files are not rendered by default. Learn more about how customized files appear on GitHub.

1 change: 1 addition & 0 deletions Lib/opcode.py
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -326,6 +326,7 @@ def pseudo_op(name, op, real_ops):
"FOR_ITER_ADAPTIVE",
"FOR_ITER_LIST",
"FOR_ITER_RANGE",
"FOR_ITER_GEN",
],
"JUMP_BACKWARD": [
"JUMP_BACKWARD_QUICK",
Expand Down
3 changes: 3 additions & 0 deletions Misc/NEWS.d/next/Core and Builtins/2022-10-28-09-42-51.gh-issue-96793.ucBfWO.rst
View file
Open in desktop
Original file line number Diff line number Diff line change
@@ -0,0 +1,3 @@
Add specialization of :opcode:`FOR_ITER` for generators. Saves multiple
layers of dispatch and checking to get from the :opcode:`FOR_ITER`
instruction in the caller to the :opcode:`RESUME` in the generator.
61 changes: 55 additions & 6 deletions Python/ceval.c
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -2012,7 +2012,6 @@ _PyEval_EvalFrameDefault(PyThreadState *tstate, _PyInterpreterFrame *frame, int
}

TARGET(SEND) {
assert(frame->is_entry);
assert(STACK_LEVEL() >= 2);
PyObject *v = POP();
PyObject *receiver = TOP();
Expand Down Expand Up @@ -2077,13 +2076,18 @@ _PyEval_EvalFrameDefault(PyThreadState *tstate, _PyInterpreterFrame *frame, int
// The compiler treats any exception raised here as a failed close()
// or throw() call.
assert(oparg == STACK_LEVEL());
assert(frame->is_entry);
PyObject *retval = POP();
_PyFrame_GetGenerator(frame)->gi_frame_state = FRAME_SUSPENDED;
_PyFrame_SetStackPointer(frame, stack_pointer);
TRACE_FUNCTION_EXIT();
DTRACE_FUNCTION_EXIT();
_Py_LeaveRecursiveCallPy(tstate);
if (!frame->is_entry) {
frame = cframe.current_frame = frame->previous;
frame->prev_instr -= frame->yield_offset;
_PyFrame_StackPush(frame, retval);
goto resume_frame;
}
_Py_LeaveRecursiveCallTstate(tstate);
/* Restore previous cframe and return. */
tstate->cframe = cframe.previous;
Expand Down Expand Up @@ -3865,7 +3869,7 @@ _PyEval_EvalFrameDefault(PyThreadState *tstate, _PyInterpreterFrame *frame, int
_PyForIterCache *cache = (_PyForIterCache *)next_instr;
if (ADAPTIVE_COUNTER_IS_ZERO(cache)) {
next_instr--;
_Py_Specialize_ForIter(TOP(), next_instr);
_Py_Specialize_ForIter(TOP(), next_instr, oparg);
DISPATCH_SAME_OPARG();
}
else {
Expand Down Expand Up @@ -3921,6 +3925,27 @@ _PyEval_EvalFrameDefault(PyThreadState *tstate, _PyInterpreterFrame *frame, int
DISPATCH();
}

TARGET(FOR_ITER_GEN) {
assert(cframe.use_tracing == 0);
PyGenObject *gen = (PyGenObject *)TOP();
DEOPT_IF(Py_TYPE(gen) != &PyGen_Type, FOR_ITER);
DEOPT_IF(gen->gi_frame_state >= FRAME_EXECUTING, FOR_ITER);
STAT_INC(FOR_ITER, hit);
_PyInterpreterFrame *gen_frame = (_PyInterpreterFrame *)gen->gi_iframe;
_PyFrame_SetStackPointer(frame, stack_pointer);
frame->yield_offset = oparg;
JUMPBY(INLINE_CACHE_ENTRIES_FOR_ITER + oparg);
assert(_Py_OPCODE(*next_instr) == END_FOR);
frame->prev_instr = next_instr - 1;
Py_INCREF(Py_None);
_PyFrame_StackPush(gen_frame, Py_None);
gen->gi_frame_state = FRAME_EXECUTING;
gen_frame->previous = frame;
gen_frame->is_entry = false;
frame = cframe.current_frame = gen_frame;
goto start_frame;
}

TARGET(BEFORE_ASYNC_WITH) {
PyObject *mgr = TOP();
PyObject *res;
Expand Down Expand Up @@ -5794,20 +5819,44 @@ _PyEvalFramePushAndInit(PyThreadState *tstate, PyFunctionObject *func,
}

static void
_PyEvalFrameClearAndPop(PyThreadState *tstate, _PyInterpreterFrame * frame)
clear_thread_frame(PyThreadState *tstate, _PyInterpreterFrame * frame)
{
assert(frame->owner == FRAME_OWNED_BY_THREAD);
// Make sure that this is, indeed, the top frame. We can't check this in
// _PyThreadState_PopFrame, since f_code is already cleared at that point:
assert((PyObject **)frame + frame->f_code->co_framesize ==
tstate->datastack_top);
tstate->datastack_top);
tstate->c_recursion_remaining--;
assert(frame->frame_obj == NULL || frame->frame_obj->f_frame == frame);
assert(frame->owner == FRAME_OWNED_BY_THREAD);
_PyFrame_Clear(frame);
tstate->c_recursion_remaining++;
_PyThreadState_PopFrame(tstate, frame);
}

static void
clear_gen_frame(PyThreadState *tstate, _PyInterpreterFrame * frame)
{
assert(frame->owner == FRAME_OWNED_BY_GENERATOR);
_PyFrame_GetGenerator(frame)->gi_frame_state = FRAME_CLEARED;
tstate->c_recursion_remaining--;
assert(frame->frame_obj == NULL || frame->frame_obj->f_frame == frame);
_PyFrame_Clear(frame);
tstate->c_recursion_remaining++;
frame->previous = NULL;
}

static void
_PyEvalFrameClearAndPop(PyThreadState *tstate, _PyInterpreterFrame * frame)
{
if (frame->owner == FRAME_OWNED_BY_THREAD) {
clear_thread_frame(tstate, frame);
}
else {
clear_gen_frame(tstate, frame);
}
}


PyObject *
_PyEval_Vector(PyThreadState *tstate, PyFunctionObject *func,
PyObject *locals,
Expand Down
Loading