GH-120024: Use pointer for stack pointer (GH-121923)

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Mark Shannon 2024-07-18 12:47:21 +01:00 committed by GitHub
parent 24cf867bed
commit 169324c27a
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GPG Key ID: B5690EEEBB952194
5 changed files with 55 additions and 43 deletions

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@ -68,7 +68,7 @@ typedef struct _PyInterpreterFrame {
PyObject *f_locals; /* Strong reference, may be NULL. Only valid if not on C stack */
PyFrameObject *frame_obj; /* Strong reference, may be NULL. Only valid if not on C stack */
_Py_CODEUNIT *instr_ptr; /* Instruction currently executing (or about to begin) */
int stacktop; /* Offset of TOS from localsplus */
_PyStackRef *stackpointer;
uint16_t return_offset; /* Only relevant during a function call */
char owner;
/* Locals and stack */
@ -88,20 +88,20 @@ static inline _PyStackRef *_PyFrame_Stackbase(_PyInterpreterFrame *f) {
}
static inline _PyStackRef _PyFrame_StackPeek(_PyInterpreterFrame *f) {
assert(f->stacktop > _PyFrame_GetCode(f)->co_nlocalsplus);
assert(!PyStackRef_IsNull(f->localsplus[f->stacktop-1]));
return f->localsplus[f->stacktop-1];
assert(f->stackpointer > f->localsplus + _PyFrame_GetCode(f)->co_nlocalsplus);
assert(!PyStackRef_IsNull(f->stackpointer[-1]));
return f->stackpointer[-1];
}
static inline _PyStackRef _PyFrame_StackPop(_PyInterpreterFrame *f) {
assert(f->stacktop > _PyFrame_GetCode(f)->co_nlocalsplus);
f->stacktop--;
return f->localsplus[f->stacktop];
assert(f->stackpointer > f->localsplus + _PyFrame_GetCode(f)->co_nlocalsplus);
f->stackpointer--;
return *f->stackpointer;
}
static inline void _PyFrame_StackPush(_PyInterpreterFrame *f, _PyStackRef value) {
f->localsplus[f->stacktop] = value;
f->stacktop++;
*f->stackpointer = value;
f->stackpointer++;
}
#define FRAME_SPECIALS_SIZE ((int)((sizeof(_PyInterpreterFrame)-1)/sizeof(PyObject *)))
@ -117,9 +117,12 @@ _PyFrame_NumSlotsForCodeObject(PyCodeObject *code)
static inline void _PyFrame_Copy(_PyInterpreterFrame *src, _PyInterpreterFrame *dest)
{
assert(src->stacktop >= _PyFrame_GetCode(src)->co_nlocalsplus);
*dest = *src;
for (int i = 1; i < src->stacktop; i++) {
assert(src->stackpointer != NULL);
int stacktop = (int)(src->stackpointer - src->localsplus);
assert(stacktop >= _PyFrame_GetCode(src)->co_nlocalsplus);
dest->stackpointer = dest->localsplus + stacktop;
for (int i = 1; i < stacktop; i++) {
dest->localsplus[i] = src->localsplus[i];
}
// Don't leave a dangling pointer to the old frame when creating generators
@ -141,7 +144,7 @@ _PyFrame_Initialize(
frame->f_builtins = func->func_builtins;
frame->f_globals = func->func_globals;
frame->f_locals = locals;
frame->stacktop = code->co_nlocalsplus;
frame->stackpointer = frame->localsplus + code->co_nlocalsplus;
frame->frame_obj = NULL;
frame->instr_ptr = _PyCode_CODE(code);
frame->return_offset = 0;
@ -161,22 +164,23 @@ _PyFrame_GetLocalsArray(_PyInterpreterFrame *frame)
return frame->localsplus;
}
/* Fetches the stack pointer, and sets stacktop to -1.
Having stacktop <= 0 ensures that invalid
values are not visible to the cycle GC.
We choose -1 rather than 0 to assist debugging. */
/* Fetches the stack pointer, and sets stackpointer to NULL.
Having stackpointer == NULL ensures that invalid
values are not visible to the cycle GC. */
static inline _PyStackRef*
_PyFrame_GetStackPointer(_PyInterpreterFrame *frame)
{
_PyStackRef *sp = frame->localsplus + frame->stacktop;
frame->stacktop = -1;
assert(frame->stackpointer != NULL);
_PyStackRef *sp = frame->stackpointer;
frame->stackpointer = NULL;
return sp;
}
static inline void
_PyFrame_SetStackPointer(_PyInterpreterFrame *frame, _PyStackRef *stack_pointer)
{
frame->stacktop = (int)(stack_pointer - frame->localsplus);
assert(frame->stackpointer == NULL);
frame->stackpointer = stack_pointer;
}
/* Determine whether a frame is incomplete.
@ -304,7 +308,8 @@ _PyFrame_PushTrampolineUnchecked(PyThreadState *tstate, PyCodeObject *code, int
frame->f_globals = NULL;
#endif
frame->f_locals = NULL;
frame->stacktop = code->co_nlocalsplus + stackdepth;
assert(stackdepth <= code->co_stacksize);
frame->stackpointer = frame->localsplus + code->co_nlocalsplus + stackdepth;
frame->frame_obj = NULL;
frame->instr_ptr = _PyCode_CODE(code);
frame->owner = FRAME_OWNED_BY_THREAD;

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@ -1603,7 +1603,8 @@ class SizeofTest(unittest.TestCase):
def func():
return sys._getframe()
x = func()
check(x, size('3Pi2c2P7P2ic??2P'))
INTERPRETER_FRAME = '9PhcP'
check(x, size('3PiccPP' + INTERPRETER_FRAME + 'P'))
# function
def func(): pass
check(func, size('16Pi'))
@ -1620,7 +1621,7 @@ class SizeofTest(unittest.TestCase):
check(bar, size('PP'))
# generator
def get_gen(): yield 1
check(get_gen(), size('PP4P4c7P2ic??2P'))
check(get_gen(), size('6P4c' + INTERPRETER_FRAME + 'P'))
# iterator
check(iter('abc'), size('lP'))
# callable-iterator

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@ -1620,8 +1620,10 @@ frame_dealloc(PyFrameObject *f)
Py_CLEAR(frame->f_funcobj);
Py_CLEAR(frame->f_locals);
_PyStackRef *locals = _PyFrame_GetLocalsArray(frame);
for (int i = 0; i < frame->stacktop; i++) {
PyStackRef_CLEAR(locals[i]);
_PyStackRef *sp = frame->stackpointer;
while (sp > locals) {
sp--;
PyStackRef_CLEAR(*sp);
}
}
Py_CLEAR(f->f_back);
@ -1656,11 +1658,13 @@ frame_tp_clear(PyFrameObject *f)
/* locals and stack */
_PyStackRef *locals = _PyFrame_GetLocalsArray(f->f_frame);
assert(f->f_frame->stacktop >= 0);
for (int i = 0; i < f->f_frame->stacktop; i++) {
PyStackRef_CLEAR(locals[i]);
_PyStackRef *sp = f->f_frame->stackpointer;
assert(sp >= locals);
while (sp > locals) {
sp--;
PyStackRef_CLEAR(*sp);
}
f->f_frame->stacktop = 0;
f->f_frame->stackpointer = locals;
Py_CLEAR(f->f_frame->f_locals);
return 0;
}
@ -1878,8 +1882,9 @@ frame_get_var(_PyInterpreterFrame *frame, PyCodeObject *co, int i,
return 0;
}
PyObject *value = PyStackRef_AsPyObjectBorrow(frame->localsplus[i]);
if (frame->stacktop) {
PyObject *value = NULL;
if (frame->stackpointer == NULL || frame->stackpointer > frame->localsplus + i) {
value = PyStackRef_AsPyObjectBorrow(frame->localsplus[i]);
if (kind & CO_FAST_FREE) {
// The cell was set by COPY_FREE_VARS.
assert(value != NULL && PyCell_Check(value));
@ -1897,9 +1902,6 @@ frame_get_var(_PyInterpreterFrame *frame, PyCodeObject *co, int i,
}
}
}
else {
assert(value == NULL);
}
*pvalue = value;
return 1;
}

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@ -764,7 +764,7 @@ _PyEval_EvalFrameDefault(PyThreadState *tstate, _PyInterpreterFrame *frame, int
#endif
entry_frame.f_executable = Py_None;
entry_frame.instr_ptr = (_Py_CODEUNIT *)_Py_INTERPRETER_TRAMPOLINE_INSTRUCTIONS + 1;
entry_frame.stacktop = 0;
entry_frame.stackpointer = entry_frame.localsplus;
entry_frame.owner = FRAME_OWNED_BY_CSTACK;
entry_frame.return_offset = 0;
/* Push frame */

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@ -17,10 +17,11 @@ _PyFrame_Traverse(_PyInterpreterFrame *frame, visitproc visit, void *arg)
Py_VISIT(_PyFrame_GetCode(frame));
/* locals */
_PyStackRef *locals = _PyFrame_GetLocalsArray(frame);
int i = 0;
_PyStackRef *sp = frame->stackpointer;
/* locals and stack */
for (; i <frame->stacktop; i++) {
Py_VISIT(PyStackRef_AsPyObjectBorrow(locals[i]));
while (sp > locals) {
sp--;
Py_VISIT(PyStackRef_AsPyObjectBorrow(*sp));
}
return 0;
}
@ -59,10 +60,11 @@ take_ownership(PyFrameObject *f, _PyInterpreterFrame *frame)
assert(frame->owner != FRAME_OWNED_BY_CSTACK);
assert(frame->owner != FRAME_OWNED_BY_FRAME_OBJECT);
assert(frame->owner != FRAME_CLEARED);
Py_ssize_t size = ((char*)&frame->localsplus[frame->stacktop]) - (char *)frame;
Py_ssize_t size = ((char*)frame->stackpointer) - (char *)frame;
Py_INCREF(_PyFrame_GetCode(frame));
memcpy((_PyInterpreterFrame *)f->_f_frame_data, frame, size);
frame = (_PyInterpreterFrame *)f->_f_frame_data;
frame->stackpointer = (_PyStackRef *)(((char *)frame) + size);
f->f_frame = frame;
frame->owner = FRAME_OWNED_BY_FRAME_OBJECT;
if (_PyFrame_IsIncomplete(frame)) {
@ -97,11 +99,13 @@ take_ownership(PyFrameObject *f, _PyInterpreterFrame *frame)
void
_PyFrame_ClearLocals(_PyInterpreterFrame *frame)
{
assert(frame->stacktop >= 0);
int stacktop = frame->stacktop;
frame->stacktop = 0;
for (int i = 0; i < stacktop; i++) {
PyStackRef_XCLOSE(frame->localsplus[i]);
assert(frame->stackpointer != NULL);
_PyStackRef *sp = frame->stackpointer;
_PyStackRef *locals = frame->localsplus;
frame->stackpointer = locals;
while (sp > locals) {
sp--;
PyStackRef_XCLOSE(*sp);
}
Py_CLEAR(frame->f_locals);
}