1 files changed, 137 insertions, 130 deletions

diff --git a/Objects/frameobject.c b/Objects/frameobject.c
index ae8cdcfb92d..1781c3cff73 100644
--- a/Objects/frameobject.c
+++ b/Objects/frameobject.c
@@ -6,6 +6,7 @@
 #include "pycore_object.h"        // _PyObject_GC_UNTRACK()
 
 #include "frameobject.h"          // PyFrameObject
+#include "pycore_frame.h"
 #include "opcode.h"               // EXTENDED_ARG
 #include "structmember.h"         // PyMemberDef
 
@@ -13,9 +14,6 @@
 
 static PyMemberDef frame_memberlist[] = {
     {"f_back",          T_OBJECT,       OFF(f_back),      READONLY},
-    {"f_code",          T_OBJECT,       OFF(f_code),      READONLY|PY_AUDIT_READ},
-    {"f_builtins",      T_OBJECT,       OFF(f_builtins),  READONLY},
-    {"f_globals",       T_OBJECT,       OFF(f_globals),   READONLY},
     {"f_trace_lines",   T_BOOL,         OFF(f_trace_lines), 0},
     {"f_trace_opcodes", T_BOOL,         OFF(f_trace_opcodes), 0},
     {NULL}      /* Sentinel */
@@ -34,8 +32,9 @@ frame_getlocals(PyFrameObject *f, void *closure)
 {
     if (PyFrame_FastToLocalsWithError(f) < 0)
         return NULL;
-    Py_INCREF(f->f_locals);
-    return f->f_locals;
+    PyObject *locals = _PyFrame_Specials(f)[FRAME_SPECIALS_LOCALS_OFFSET];
+    Py_INCREF(locals);
+    return locals;
 }
 
 int
@@ -71,6 +70,36 @@ frame_getlasti(PyFrameObject *f, void *closure)
     return PyLong_FromLong(f->f_lasti*2);
 }
 
+static PyObject *
+frame_getglobals(PyFrameObject *f, void *closure)
+{
+    PyObject *globals = _PyFrame_GetGlobals(f);
+    if (globals == NULL) {
+        globals = Py_None;
+    }
+    Py_INCREF(globals);
+    return globals;
+}
+
+static PyObject *
+frame_getbuiltins(PyFrameObject *f, void *closure)
+{
+    PyObject *builtins = _PyFrame_GetBuiltins(f);
+    if (builtins == NULL) {
+        builtins = Py_None;
+    }
+    Py_INCREF(builtins);
+    return builtins;
+}
+
+static PyObject *
+frame_getcode(PyFrameObject *f, void *closure)
+{
+    if (PySys_Audit("object.__getattr__", "Os", f, "f_code") < 0) {
+        return NULL;
+    }
+    return (PyObject *)PyFrame_GetCode(f);
+}
 
 /* Given the index of the effective opcode,
    scan back to construct the oparg with EXTENDED_ARG */
@@ -554,50 +583,21 @@ static PyGetSetDef frame_getsetlist[] = {
                     (setter)frame_setlineno, NULL},
     {"f_trace",         (getter)frame_gettrace, (setter)frame_settrace, NULL},
     {"f_lasti",         (getter)frame_getlasti, NULL, NULL},
+    {"f_globals",       (getter)frame_getglobals, NULL, NULL},
+    {"f_builtins",      (getter)frame_getbuiltins, NULL, NULL},
+    {"f_code",          (getter)frame_getcode, NULL, NULL},
     {0}
 };
 
 /* Stack frames are allocated and deallocated at a considerable rate.
-   In an attempt to improve the speed of function calls, we:
-
-   1. Hold a single "zombie" frame on each code object. This retains
-   the allocated and initialised frame object from an invocation of
-   the code object. The zombie is reanimated the next time we need a
-   frame object for that code object. Doing this saves the malloc/
-   realloc required when using a free_list frame that isn't the
-   correct size. It also saves some field initialisation.
-
-   In zombie mode, no field of PyFrameObject holds a reference, but
-   the following fields are still valid:
-
-     * ob_type, ob_size, f_code, f_valuestack;
-
-     * f_locals, f_trace are NULL;
-
-     * f_localsplus does not require re-allocation and
-       the local variables in f_localsplus are NULL.
-
-   2. We also maintain a separate free list of stack frames (just like
-   floats are allocated in a special way -- see floatobject.c).  When
-   a stack frame is on the free list, only the following members have
-   a meaning:
+   In an attempt to improve the speed of function calls, we maintain
+   a separate free list of stack frames (just like floats are
+   allocated in a special way -- see floatobject.c).  When a stack
+   frame is on the free list, only the following members have a meaning:
     ob_type             == &Frametype
     f_back              next item on free list, or NULL
-    f_stacksize         size of value stack
-    ob_size             size of localsplus
-   Note that the value and block stacks are preserved -- this can save
-   another malloc() call or two (and two free() calls as well!).
-   Also note that, unlike for integers, each frame object is a
-   malloc'ed object in its own right -- it is only the actual calls to
-   malloc() that we are trying to save here, not the administration.
-   After all, while a typical program may make millions of calls, a
-   call depth of more than 20 or 30 is probably already exceptional
-   unless the program contains run-away recursion.  I hope.
-
-   Later, PyFrame_MAXFREELIST was added to bound the # of frames saved on
-   free_list.  Else programs creating lots of cyclic trash involving
-   frames could provoke free_list into growing without bound.
 */
+
 /* max value for numfree */
 #define PyFrame_MAXFREELIST 200
 
@@ -609,42 +609,37 @@ frame_dealloc(PyFrameObject *f)
     }
 
     Py_TRASHCAN_SAFE_BEGIN(f)
-    /* Kill all local variables */
-    PyObject **valuestack = f->f_valuestack;
-    for (PyObject **p = f->f_localsplus; p < valuestack; p++) {
-        Py_CLEAR(*p);
-    }
+    PyCodeObject *co = f->f_code;
 
-    /* Free stack */
-    for (int i = 0; i < f->f_stackdepth; i++) {
-        Py_XDECREF(f->f_valuestack[i]);
+    /* Kill all local variables */
+    if (f->f_localsptr) {
+        for (int i = 0; i < co->co_nlocalsplus+FRAME_SPECIALS_SIZE; i++) {
+            Py_CLEAR(f->f_localsptr[i]);
+        }
+        /* Free items on stack */
+        for (int i = 0; i < f->f_stackdepth; i++) {
+            Py_XDECREF(f->f_valuestack[i]);
+        }
+        if (f->f_own_locals_memory) {
+            PyMem_Free(f->f_localsptr);
+            f->f_own_locals_memory = 0;
+        }
     }
     f->f_stackdepth = 0;
-
     Py_XDECREF(f->f_back);
-    Py_DECREF(f->f_builtins);
-    Py_DECREF(f->f_globals);
-    Py_CLEAR(f->f_locals);
     Py_CLEAR(f->f_trace);
-
-    PyCodeObject *co = f->f_code;
-    if (co->co_zombieframe == NULL) {
-        co->co_zombieframe = f;
-    }
-    else {
-        struct _Py_frame_state *state = get_frame_state();
+    struct _Py_frame_state *state = get_frame_state();
 #ifdef Py_DEBUG
-        // frame_dealloc() must not be called after _PyFrame_Fini()
-        assert(state->numfree != -1);
+    // frame_dealloc() must not be called after _PyFrame_Fini()
+    assert(state->numfree != -1);
 #endif
-        if (state->numfree < PyFrame_MAXFREELIST) {
-            ++state->numfree;
-            f->f_back = state->free_list;
-            state->free_list = f;
-        }
-        else {
-            PyObject_GC_Del(f);
-        }
+    if (state->numfree < PyFrame_MAXFREELIST) {
+        ++state->numfree;
+        f->f_back = state->free_list;
+        state->free_list = f;
+    }
+    else {
+        PyObject_GC_Del(f);
     }
 
     Py_DECREF(co);
@@ -654,24 +649,17 @@ frame_dealloc(PyFrameObject *f)
 static inline Py_ssize_t
 frame_nslots(PyFrameObject *frame)
 {
-    PyCodeObject *code = frame->f_code;
-    return (code->co_nlocals
-            + PyTuple_GET_SIZE(code->co_cellvars)
-            + PyTuple_GET_SIZE(code->co_freevars));
+    return frame->f_valuestack - frame->f_localsptr;
 }
 
 static int
 frame_traverse(PyFrameObject *f, visitproc visit, void *arg)
 {
     Py_VISIT(f->f_back);
-    Py_VISIT(f->f_code);
-    Py_VISIT(f->f_builtins);
-    Py_VISIT(f->f_globals);
-    Py_VISIT(f->f_locals);
     Py_VISIT(f->f_trace);
 
     /* locals */
-    PyObject **fastlocals = f->f_localsplus;
+    PyObject **fastlocals = f->f_localsptr;
     for (Py_ssize_t i = frame_nslots(f); --i >= 0; ++fastlocals) {
         Py_VISIT(*fastlocals);
     }
@@ -696,7 +684,7 @@ frame_tp_clear(PyFrameObject *f)
     Py_CLEAR(f->f_trace);
 
     /* locals */
-    PyObject **fastlocals = f->f_localsplus;
+    PyObject **fastlocals = f->f_localsptr;
     for (Py_ssize_t i = frame_nslots(f); --i >= 0; ++fastlocals) {
         Py_CLEAR(*fastlocals);
     }
@@ -731,15 +719,12 @@ PyDoc_STRVAR(clear__doc__,
 static PyObject *
 frame_sizeof(PyFrameObject *f, PyObject *Py_UNUSED(ignored))
 {
-    Py_ssize_t res, extras, ncells, nfrees;
-
-    PyCodeObject *code = f->f_code;
-    ncells = PyTuple_GET_SIZE(code->co_cellvars);
-    nfrees = PyTuple_GET_SIZE(code->co_freevars);
-    extras = code->co_stacksize + code->co_nlocals + ncells + nfrees;
-    /* subtract one as it is already included in PyFrameObject */
-    res = sizeof(PyFrameObject) + (extras-1) * sizeof(PyObject *);
-
+    Py_ssize_t res;
+    res = sizeof(PyFrameObject);
+    if (f->f_own_locals_memory) {
+        PyCodeObject *code = f->f_code;
+        res += (code->co_nlocalsplus+code->co_stacksize) * sizeof(PyObject *);
+    }
     return PyLong_FromSsize_t(res);
 }
 
@@ -802,24 +787,33 @@ PyTypeObject PyFrame_Type = {
 _Py_IDENTIFIER(__builtins__);
 
 static inline PyFrameObject*
-frame_alloc(PyCodeObject *code)
+frame_alloc(PyCodeObject *code, PyObject **localsarray)
 {
-    PyFrameObject *f = code->co_zombieframe;
-    if (f != NULL) {
-        code->co_zombieframe = NULL;
-        _Py_NewReference((PyObject *)f);
-        assert(f->f_code == code);
-        return f;
+    int owns;
+    PyFrameObject *f;
+    if (localsarray == NULL) {
+        int size = code->co_nlocalsplus+code->co_stacksize + FRAME_SPECIALS_SIZE;
+        localsarray = PyMem_Malloc(sizeof(PyObject *)*size);
+        if (localsarray == NULL) {
+            PyErr_NoMemory();
+            return NULL;
+        }
+        for (Py_ssize_t i=0; i < code->co_nlocalsplus; i++) {
+            localsarray[i] = NULL;
+        }
+        owns = 1;
+    }
+    else {
+        owns = 0;
     }
-
-    Py_ssize_t ncells = PyTuple_GET_SIZE(code->co_cellvars);
-    Py_ssize_t nfrees = PyTuple_GET_SIZE(code->co_freevars);
-    Py_ssize_t extras = code->co_stacksize + code->co_nlocals + ncells + nfrees;
     struct _Py_frame_state *state = get_frame_state();
     if (state->free_list == NULL)
     {
-        f = PyObject_GC_NewVar(PyFrameObject, &PyFrame_Type, extras);
+        f = PyObject_GC_New(PyFrameObject, &PyFrame_Type);
         if (f == NULL) {
+            if (owns) {
+                PyMem_Free(localsarray);
+            }
             return NULL;
         }
     }
@@ -832,46 +826,60 @@ frame_alloc(PyCodeObject *code)
         --state->numfree;
         f = state->free_list;
         state->free_list = state->free_list->f_back;
-        if (Py_SIZE(f) < extras) {
-            PyFrameObject *new_f = PyObject_GC_Resize(PyFrameObject, f, extras);
-            if (new_f == NULL) {
-                PyObject_GC_Del(f);
-                return NULL;
-            }
-            f = new_f;
-        }
         _Py_NewReference((PyObject *)f);
     }
-
-    extras = code->co_nlocals + ncells + nfrees;
-    f->f_valuestack = f->f_localsplus + extras;
-    for (Py_ssize_t i=0; i < extras; i++) {
-        f->f_localsplus[i] = NULL;
-    }
+    f->f_localsptr = localsarray;
+    f->f_own_locals_memory = owns;
     return f;
 }
 
+int
+_PyFrame_TakeLocals(PyFrameObject *f)
+{
+    assert(f->f_own_locals_memory == 0);
+    assert(f->f_stackdepth == 0);
+    int size = frame_nslots(f);
+    PyObject **copy = PyMem_Malloc(sizeof(PyObject *)*size);
+    if (copy == NULL) {
+        for (int i = 0; i < size; i++) {
+            PyObject *o = f->f_localsptr[i];
+            Py_XDECREF(o);
+        }
+        PyErr_NoMemory();
+        return -1;
+    }
+    for (int i = 0; i < size; i++) {
+        PyObject *o = f->f_localsptr[i];
+        copy[i] = o;
+    }
+    f->f_own_locals_memory = 1;
+    f->f_localsptr = copy;
+    f->f_valuestack = copy + size;
+    return 0;
+}
 
 PyFrameObject* _Py_HOT_FUNCTION
-_PyFrame_New_NoTrack(PyThreadState *tstate, PyFrameConstructor *con, PyObject *locals)
+_PyFrame_New_NoTrack(PyThreadState *tstate, PyFrameConstructor *con, PyObject *locals, PyObject **localsarray)
 {
     assert(con != NULL);
     assert(con->fc_globals != NULL);
     assert(con->fc_builtins != NULL);
     assert(con->fc_code != NULL);
     assert(locals == NULL || PyMapping_Check(locals));
+    PyCodeObject *code = (PyCodeObject *)con->fc_code;
 
-    PyFrameObject *f = frame_alloc((PyCodeObject *)con->fc_code);
+    PyFrameObject *f = frame_alloc(code, localsarray);
     if (f == NULL) {
         return NULL;
     }
 
+    PyObject **specials = f->f_localsptr + code->co_nlocalsplus;
+    f->f_valuestack = specials + FRAME_SPECIALS_SIZE;
     f->f_back = (PyFrameObject*)Py_XNewRef(tstate->frame);
     f->f_code = (PyCodeObject *)Py_NewRef(con->fc_code);
-    f->f_builtins = Py_NewRef(con->fc_builtins);
-    f->f_globals = Py_NewRef(con->fc_globals);
-    f->f_locals = Py_XNewRef(locals);
-    // f_valuestack initialized by frame_alloc()
+    specials[FRAME_SPECIALS_BUILTINS_OFFSET] = Py_NewRef(con->fc_builtins);
+    specials[FRAME_SPECIALS_GLOBALS_OFFSET] = Py_NewRef(con->fc_globals);
+    specials[FRAME_SPECIALS_LOCALS_OFFSET] = Py_XNewRef(locals);
     f->f_trace = NULL;
     f->f_stackdepth = 0;
     f->f_trace_lines = 1;
@@ -880,7 +888,6 @@ _PyFrame_New_NoTrack(PyThreadState *tstate, PyFrameConstructor *con, PyObject *l
     f->f_lasti = -1;
     f->f_lineno = 0;
     f->f_state = FRAME_CREATED;
-    // f_blockstack and f_localsplus initialized by frame_alloc()
     return f;
 }
 
@@ -903,7 +910,7 @@ PyFrame_New(PyThreadState *tstate, PyCodeObject *code,
         .fc_kwdefaults = NULL,
         .fc_closure = NULL
     };
-    PyFrameObject *f = _PyFrame_New_NoTrack(tstate, &desc, locals);
+    PyFrameObject *f = _PyFrame_New_NoTrack(tstate, &desc, locals, NULL);
     if (f) {
         _PyObject_GC_TRACK(f);
     }
@@ -1022,9 +1029,9 @@ PyFrame_FastToLocalsWithError(PyFrameObject *f)
         PyErr_BadInternalCall();
         return -1;
     }
-    locals = f->f_locals;
+    locals = _PyFrame_Specials(f)[FRAME_SPECIALS_LOCALS_OFFSET];
     if (locals == NULL) {
-        locals = f->f_locals = PyDict_New();
+        locals = _PyFrame_Specials(f)[FRAME_SPECIALS_LOCALS_OFFSET] = PyDict_New();
         if (locals == NULL)
             return -1;
     }
@@ -1036,7 +1043,7 @@ PyFrame_FastToLocalsWithError(PyFrameObject *f)
                      Py_TYPE(map)->tp_name);
         return -1;
     }
-    fast = f->f_localsplus;
+    fast = f->f_localsptr;
     j = PyTuple_GET_SIZE(map);
     if (j > co->co_nlocals)
         j = co->co_nlocals;
@@ -1083,7 +1090,7 @@ PyFrame_FastToLocals(PyFrameObject *f)
 void
 PyFrame_LocalsToFast(PyFrameObject *f, int clear)
 {
-    /* Merge f->f_locals into fast locals */
+    /* Merge locals into fast locals */
     PyObject *locals, *map;
     PyObject **fast;
     PyObject *error_type, *error_value, *error_traceback;
@@ -1092,7 +1099,7 @@ PyFrame_LocalsToFast(PyFrameObject *f, int clear)
     Py_ssize_t ncells, nfreevars;
     if (f == NULL)
         return;
-    locals = f->f_locals;
+    locals = _PyFrame_Specials(f)[FRAME_SPECIALS_LOCALS_OFFSET];
     co = f->f_code;
     map = co->co_varnames;
     if (locals == NULL)
@@ -1100,7 +1107,7 @@ PyFrame_LocalsToFast(PyFrameObject *f, int clear)
     if (!PyTuple_Check(map))
         return;
     PyErr_Fetch(&error_type, &error_value, &error_traceback);
-    fast = f->f_localsplus;
+    fast = f->f_localsptr;
     j = PyTuple_GET_SIZE(map);
     if (j > co->co_nlocals)
         j = co->co_nlocals;