gh-93382: Cache result of PyCode_GetCode in codeobject (GH-93383)

Co-authored-by: Kumar Aditya <[email protected]>
Co-authored-by: Dennis Sweeney <[email protected]>

Author: 3 people

Include/cpython/code.h

@@ -88,6 +88,7 @@ typedef uint16_t _Py_CODEUNIT;
     PyObject *co_qualname;        /* unicode (qualname, for reference) */      \
     PyObject *co_linetable;       /* bytes object that holds location info */  \
     PyObject *co_weakreflist;     /* to support weakrefs to code objects */    \
+    void *_co_code;               /* cached co_code object/attribute */        \
     /* Scratch space for extra data relating to the code object.               \
        Type is a void* to keep the format private in codeobject.c to force     \
        people to go through the proper APIs. */                                \

Misc/NEWS.d/next/Core and Builtins/2022-05-31-16-36-30.gh-issue-93382.Jf6gAj.rst

@@ -0,0 +1 @@
+Speed up the :c:func:`PyCode_GetCode` function which also improves accessing the :attr:`~types.CodeType.co_code` attribute in Python.

Objects/codeobject.c

@@ -334,6 +334,7 @@ init_code(PyCodeObject *co, struct _PyCodeConstructor *con)
     /* not set */
     co->co_weakreflist = NULL;
     co->co_extra = NULL;
+    co->_co_code = NULL;
 
     co->co_warmup = QUICKENING_INITIAL_WARMUP_VALUE;
     memcpy(_PyCode_CODE(co), PyBytes_AS_STRING(con->code),
@@ -1367,12 +1368,17 @@ deopt_code(_Py_CODEUNIT *instructions, Py_ssize_t len)
 PyObject *
 _PyCode_GetCode(PyCodeObject *co)
 {
+    if (co->_co_code != NULL) {
+        return Py_NewRef(co->_co_code);
+    }
     PyObject *code = PyBytes_FromStringAndSize((const char *)_PyCode_CODE(co),
                                                _PyCode_NBYTES(co));
     if (code == NULL) {
         return NULL;
     }
     deopt_code((_Py_CODEUNIT *)PyBytes_AS_STRING(code), Py_SIZE(co));
+    assert(co->_co_code == NULL);
+    co->_co_code = (void *)Py_NewRef(code);
     return code;
 }
 
@@ -1531,6 +1537,7 @@ code_dealloc(PyCodeObject *co)
     Py_XDECREF(co->co_qualname);
     Py_XDECREF(co->co_linetable);
     Py_XDECREF(co->co_exceptiontable);
+    Py_XDECREF(co->_co_code);
     if (co->co_weakreflist != NULL) {
         PyObject_ClearWeakRefs((PyObject*)co);
     }

Objects/frameobject.c

@@ -458,22 +458,30 @@ _PyFrame_GetState(PyFrameObject *frame)
 static void
 add_load_fast_null_checks(PyCodeObject *co)
 {
+    int changed = 0;
     _Py_CODEUNIT *instructions = _PyCode_CODE(co);
     for (Py_ssize_t i = 0; i < Py_SIZE(co); i++) {
         switch (_Py_OPCODE(instructions[i])) {
             case LOAD_FAST:
             case LOAD_FAST__LOAD_FAST:
             case LOAD_FAST__LOAD_CONST:
+                changed = 1;
                 _Py_SET_OPCODE(instructions[i], LOAD_FAST_CHECK);
                 break;
             case LOAD_CONST__LOAD_FAST:
+                changed = 1;
                 _Py_SET_OPCODE(instructions[i], LOAD_CONST);
                 break;
             case STORE_FAST__LOAD_FAST:
+                changed = 1;
                 _Py_SET_OPCODE(instructions[i], STORE_FAST);
                 break;
         }
     }
+    if (changed) {
+        // invalidate cached co_code object
+        Py_CLEAR(co->_co_code);
+    }
 }
 
 /* Setter for f_lineno - you can set f_lineno from within a trace function in