gh-100758: Refactor initialisation of frame headers into a single function (_PyFrame_Initialize) (GH-100759)

5 files changed, 21 insertions, 53 deletions

diff --git a/Include/internal/pycore_frame.h b/Include/internal/pycore_frame.h
index d5c1dcc..4e2051f 100644
--- a/Include/internal/pycore_frame.h
+++ b/Include/internal/pycore_frame.h
@@ -110,9 +110,9 @@ void _PyFrame_Copy(_PyInterpreterFrame *src, _PyInterpreterFrame *dest);
    when frame is linked into the frame stack.
  */
 static inline void
-_PyFrame_InitializeSpecials(
+_PyFrame_Initialize(
     _PyInterpreterFrame *frame, PyFunctionObject *func,
-    PyObject *locals, PyCodeObject *code)
+    PyObject *locals, PyCodeObject *code, int null_locals_from)
 {
     frame->f_funcobj = (PyObject *)func;
     frame->f_code = (PyCodeObject *)Py_NewRef(code);
@@ -124,6 +124,10 @@ _PyFrame_InitializeSpecials(
     frame->prev_instr = _PyCode_CODE(code) - 1;
     frame->yield_offset = 0;
     frame->owner = FRAME_OWNED_BY_THREAD;
+
+    for (int i = null_locals_from; i < code->co_nlocalsplus; i++) {
+        frame->localsplus[i] = NULL;
+    }
 }
 
 /* Gets the pointer to the locals array
@@ -224,14 +228,14 @@ void _PyThreadState_PopFrame(PyThreadState *tstate, _PyInterpreterFrame *frame);
  * Must be guarded by _PyThreadState_HasStackSpace()
  * Consumes reference to func. */
 static inline _PyInterpreterFrame *
-_PyFrame_PushUnchecked(PyThreadState *tstate, PyFunctionObject *func)
+_PyFrame_PushUnchecked(PyThreadState *tstate, PyFunctionObject *func, int null_locals_from)
 {
     CALL_STAT_INC(frames_pushed);
     PyCodeObject *code = (PyCodeObject *)func->func_code;
     _PyInterpreterFrame *new_frame = (_PyInterpreterFrame *)tstate->datastack_top;
     tstate->datastack_top += code->co_framesize;
     assert(tstate->datastack_top < tstate->datastack_limit);
-    _PyFrame_InitializeSpecials(new_frame, func, NULL, code);
+    _PyFrame_Initialize(new_frame, func, NULL, code, null_locals_from);
     return new_frame;
 }
 
diff --git a/Objects/frameobject.c b/Objects/frameobject.c
index 8d7ee4b..ebe3bfe 100644
--- a/Objects/frameobject.c
+++ b/Objects/frameobject.c
@@ -1011,12 +1011,9 @@ static void
 init_frame(_PyInterpreterFrame *frame, PyFunctionObject *func, PyObject *locals)
 {
     PyCodeObject *code = (PyCodeObject *)func->func_code;
-    _PyFrame_InitializeSpecials(frame, (PyFunctionObject*)Py_NewRef(func),
-                                Py_XNewRef(locals), code);
+    _PyFrame_Initialize(frame, (PyFunctionObject*)Py_NewRef(func),
+                        Py_XNewRef(locals), code, 0);
     frame->previous = NULL;
-    for (Py_ssize_t i = 0; i < code->co_nlocalsplus; i++) {
-        frame->localsplus[i] = NULL;
-    }
 }
 
 PyFrameObject*
diff --git a/Python/bytecodes.c b/Python/bytecodes.c
index 6e20ba6..251ee56 100644
--- a/Python/bytecodes.c
+++ b/Python/bytecodes.c
@@ -448,13 +448,10 @@ dummy_func(
             DEOPT_IF(!_PyThreadState_HasStackSpace(tstate, code->co_framesize), BINARY_SUBSCR);
             STAT_INC(BINARY_SUBSCR, hit);
             Py_INCREF(getitem);
-            _PyInterpreterFrame *new_frame = _PyFrame_PushUnchecked(tstate, getitem);
+            _PyInterpreterFrame *new_frame = _PyFrame_PushUnchecked(tstate, getitem, 2);
             STACK_SHRINK(2);
             new_frame->localsplus[0] = container;
             new_frame->localsplus[1] = sub;
-            for (int i = 2; i < code->co_nlocalsplus; i++) {
-                new_frame->localsplus[i] = NULL;
-            }
             JUMPBY(INLINE_CACHE_ENTRIES_BINARY_SUBSCR);
             DISPATCH_INLINED(new_frame);
         }
@@ -1714,14 +1711,11 @@ dummy_func(
             DEOPT_IF(!_PyThreadState_HasStackSpace(tstate, code->co_framesize), LOAD_ATTR);
             STAT_INC(LOAD_ATTR, hit);
             Py_INCREF(fget);
-            _PyInterpreterFrame *new_frame = _PyFrame_PushUnchecked(tstate, f);
+            _PyInterpreterFrame *new_frame = _PyFrame_PushUnchecked(tstate, f, 1);
             SET_TOP(NULL);
             int shrink_stack = !(oparg & 1);
             STACK_SHRINK(shrink_stack);
             new_frame->localsplus[0] = owner;
-            for (int i = 1; i < code->co_nlocalsplus; i++) {
-                new_frame->localsplus[i] = NULL;
-            }
             JUMPBY(INLINE_CACHE_ENTRIES_LOAD_ATTR);
             DISPATCH_INLINED(new_frame);
         }
@@ -1749,15 +1743,12 @@ dummy_func(
 
             PyObject *name = GETITEM(names, oparg >> 1);
             Py_INCREF(f);
-            _PyInterpreterFrame *new_frame = _PyFrame_PushUnchecked(tstate, f);
+            _PyInterpreterFrame *new_frame = _PyFrame_PushUnchecked(tstate, f, 2);
             SET_TOP(NULL);
             int shrink_stack = !(oparg & 1);
             STACK_SHRINK(shrink_stack);
             new_frame->localsplus[0] = owner;
             new_frame->localsplus[1] = Py_NewRef(name);
-            for (int i = 2; i < code->co_nlocalsplus; i++) {
-                new_frame->localsplus[i] = NULL;
-            }
             JUMPBY(INLINE_CACHE_ENTRIES_LOAD_ATTR);
             DISPATCH_INLINED(new_frame);
         }
@@ -2672,14 +2663,11 @@ dummy_func(
             DEOPT_IF(code->co_argcount != argcount, CALL);
             DEOPT_IF(!_PyThreadState_HasStackSpace(tstate, code->co_framesize), CALL);
             STAT_INC(CALL, hit);
-            _PyInterpreterFrame *new_frame = _PyFrame_PushUnchecked(tstate, func);
+            _PyInterpreterFrame *new_frame = _PyFrame_PushUnchecked(tstate, func, argcount);
             STACK_SHRINK(argcount);
             for (int i = 0; i < argcount; i++) {
                 new_frame->localsplus[i] = stack_pointer[i];
             }
-            for (int i = argcount; i < code->co_nlocalsplus; i++) {
-                new_frame->localsplus[i] = NULL;
-            }
             STACK_SHRINK(2-is_meth);
             JUMPBY(INLINE_CACHE_ENTRIES_CALL);
             DISPATCH_INLINED(new_frame);
@@ -2702,7 +2690,7 @@ dummy_func(
             DEOPT_IF(argcount < minargs, CALL);
             DEOPT_IF(!_PyThreadState_HasStackSpace(tstate, code->co_framesize), CALL);
             STAT_INC(CALL, hit);
-            _PyInterpreterFrame *new_frame = _PyFrame_PushUnchecked(tstate, func);
+            _PyInterpreterFrame *new_frame = _PyFrame_PushUnchecked(tstate, func, code->co_argcount);
             STACK_SHRINK(argcount);
             for (int i = 0; i < argcount; i++) {
                 new_frame->localsplus[i] = stack_pointer[i];
@@ -2712,9 +2700,6 @@ dummy_func(
                                                  i - minargs);
                 new_frame->localsplus[i] = Py_NewRef(def);
             }
-            for (int i = code->co_argcount; i < code->co_nlocalsplus; i++) {
-                new_frame->localsplus[i] = NULL;
-            }
             STACK_SHRINK(2-is_meth);
             JUMPBY(INLINE_CACHE_ENTRIES_CALL);
             DISPATCH_INLINED(new_frame);
diff --git a/Python/ceval.c b/Python/ceval.c
index 149b88e..56cd9ad 100644
--- a/Python/ceval.c
+++ b/Python/ceval.c
@@ -1974,11 +1974,8 @@ _PyEvalFramePushAndInit(PyThreadState *tstate, PyFunctionObject *func,
     if (frame == NULL) {
         goto fail;
     }
-    _PyFrame_InitializeSpecials(frame, func, locals, code);
+    _PyFrame_Initialize(frame, func, locals, code, 0);
     PyObject **localsarray = &frame->localsplus[0];
-    for (int i = 0; i < code->co_nlocalsplus; i++) {
-        localsarray[i] = NULL;
-    }
     if (initialize_locals(tstate, func, localsarray, args, argcount, kwnames)) {
         assert(frame->owner != FRAME_OWNED_BY_GENERATOR);
         _PyEvalFrameClearAndPop(tstate, frame);
diff --git a/Python/generated_cases.c.h b/Python/generated_cases.c.h
index beb5bec..218bc62 100644
--- a/Python/generated_cases.c.h
+++ b/Python/generated_cases.c.h
@@ -564,13 +564,10 @@
             DEOPT_IF(!_PyThreadState_HasStackSpace(tstate, code->co_framesize), BINARY_SUBSCR);
             STAT_INC(BINARY_SUBSCR, hit);
             Py_INCREF(getitem);
-            _PyInterpreterFrame *new_frame = _PyFrame_PushUnchecked(tstate, getitem);
+            _PyInterpreterFrame *new_frame = _PyFrame_PushUnchecked(tstate, getitem, 2);
             STACK_SHRINK(2);
             new_frame->localsplus[0] = container;
             new_frame->localsplus[1] = sub;
-            for (int i = 2; i < code->co_nlocalsplus; i++) {
-                new_frame->localsplus[i] = NULL;
-            }
             JUMPBY(INLINE_CACHE_ENTRIES_BINARY_SUBSCR);
             DISPATCH_INLINED(new_frame);
         }
@@ -1941,14 +1938,11 @@
             DEOPT_IF(!_PyThreadState_HasStackSpace(tstate, code->co_framesize), LOAD_ATTR);
             STAT_INC(LOAD_ATTR, hit);
             Py_INCREF(fget);
-            _PyInterpreterFrame *new_frame = _PyFrame_PushUnchecked(tstate, f);
+            _PyInterpreterFrame *new_frame = _PyFrame_PushUnchecked(tstate, f, 1);
             SET_TOP(NULL);
             int shrink_stack = !(oparg & 1);
             STACK_SHRINK(shrink_stack);
             new_frame->localsplus[0] = owner;
-            for (int i = 1; i < code->co_nlocalsplus; i++) {
-                new_frame->localsplus[i] = NULL;
-            }
             JUMPBY(INLINE_CACHE_ENTRIES_LOAD_ATTR);
             DISPATCH_INLINED(new_frame);
         }
@@ -1975,15 +1969,12 @@
 
             PyObject *name = GETITEM(names, oparg >> 1);
             Py_INCREF(f);
-            _PyInterpreterFrame *new_frame = _PyFrame_PushUnchecked(tstate, f);
+            _PyInterpreterFrame *new_frame = _PyFrame_PushUnchecked(tstate, f, 2);
             SET_TOP(NULL);
             int shrink_stack = !(oparg & 1);
             STACK_SHRINK(shrink_stack);
             new_frame->localsplus[0] = owner;
             new_frame->localsplus[1] = Py_NewRef(name);
-            for (int i = 2; i < code->co_nlocalsplus; i++) {
-                new_frame->localsplus[i] = NULL;
-            }
             JUMPBY(INLINE_CACHE_ENTRIES_LOAD_ATTR);
             DISPATCH_INLINED(new_frame);
         }
@@ -3011,14 +3002,11 @@
             DEOPT_IF(code->co_argcount != argcount, CALL);
             DEOPT_IF(!_PyThreadState_HasStackSpace(tstate, code->co_framesize), CALL);
             STAT_INC(CALL, hit);
-            _PyInterpreterFrame *new_frame = _PyFrame_PushUnchecked(tstate, func);
+            _PyInterpreterFrame *new_frame = _PyFrame_PushUnchecked(tstate, func, argcount);
             STACK_SHRINK(argcount);
             for (int i = 0; i < argcount; i++) {
                 new_frame->localsplus[i] = stack_pointer[i];
             }
-            for (int i = argcount; i < code->co_nlocalsplus; i++) {
-                new_frame->localsplus[i] = NULL;
-            }
             STACK_SHRINK(2-is_meth);
             JUMPBY(INLINE_CACHE_ENTRIES_CALL);
             DISPATCH_INLINED(new_frame);
@@ -3040,7 +3028,7 @@
             DEOPT_IF(argcount < minargs, CALL);
             DEOPT_IF(!_PyThreadState_HasStackSpace(tstate, code->co_framesize), CALL);
             STAT_INC(CALL, hit);
-            _PyInterpreterFrame *new_frame = _PyFrame_PushUnchecked(tstate, func);
+            _PyInterpreterFrame *new_frame = _PyFrame_PushUnchecked(tstate, func, code->co_argcount);
             STACK_SHRINK(argcount);
             for (int i = 0; i < argcount; i++) {
                 new_frame->localsplus[i] = stack_pointer[i];
@@ -3050,9 +3038,6 @@
                                                  i - minargs);
                 new_frame->localsplus[i] = Py_NewRef(def);
             }
-            for (int i = code->co_argcount; i < code->co_nlocalsplus; i++) {
-                new_frame->localsplus[i] = NULL;
-            }
             STACK_SHRINK(2-is_meth);
             JUMPBY(INLINE_CACHE_ENTRIES_CALL);
             DISPATCH_INLINED(new_frame);