[Python-checkins] bpo-39542: Make PyObject_INIT() opaque in limited C API (GH-18363)
Victor Stinner
webhook-mailer at python.org
Wed Feb 5 07:12:27 EST 2020
https://github.com/python/cpython/commit/f58bd7c1693fe041f7296a5778d0a11287895648
commit: f58bd7c1693fe041f7296a5778d0a11287895648
branch: master
author: Victor Stinner <vstinner at python.org>
committer: GitHub <noreply at github.com>
date: 2020-02-05T13:12:19+01:00
summary:
bpo-39542: Make PyObject_INIT() opaque in limited C API (GH-18363)
In the limited C API, PyObject_INIT() and PyObject_INIT_VAR() are now
defined as aliases to PyObject_Init() and PyObject_InitVar() to make
their implementation opaque. It avoids to leak implementation details
in the limited C API.
Exclude the following functions from the limited C API, move them
from object.h to cpython/object.h:
* _Py_NewReference()
* _Py_ForgetReference()
* _PyTraceMalloc_NewReference()
* _Py_GetRefTotal()
files:
A Misc/NEWS.d/next/C API/2020-02-05-12-40-51.bpo-39542.si-_Zq.rst
M Include/cpython/object.h
M Include/cpython/objimpl.h
M Include/object.h
M Include/objimpl.h
M Objects/object.c
diff --git a/Include/cpython/object.h b/Include/cpython/object.h
index 3c4bf5bb5949a..e36f824eeb356 100644
--- a/Include/cpython/object.h
+++ b/Include/cpython/object.h
@@ -6,6 +6,22 @@
extern "C" {
#endif
+PyAPI_FUNC(void) _Py_NewReference(PyObject *op);
+
+#ifdef Py_TRACE_REFS
+/* Py_TRACE_REFS is such major surgery that we call external routines. */
+PyAPI_FUNC(void) _Py_ForgetReference(PyObject *);
+#endif
+
+/* Update the Python traceback of an object. This function must be called
+ when a memory block is reused from a free list. */
+PyAPI_FUNC(int) _PyTraceMalloc_NewReference(PyObject *op);
+
+#ifdef Py_REF_DEBUG
+PyAPI_FUNC(Py_ssize_t) _Py_GetRefTotal(void);
+#endif
+
+
/********************* String Literals ****************************************/
/* This structure helps managing static strings. The basic usage goes like this:
Instead of doing
diff --git a/Include/cpython/objimpl.h b/Include/cpython/objimpl.h
index f121922bc42ce..3f148146f67a4 100644
--- a/Include/cpython/objimpl.h
+++ b/Include/cpython/objimpl.h
@@ -6,6 +6,39 @@
extern "C" {
#endif
+/* Inline functions trading binary compatibility for speed:
+ PyObject_INIT() is the fast version of PyObject_Init(), and
+ PyObject_INIT_VAR() is the fast version of PyObject_InitVar().
+
+ These inline functions must not be called with op=NULL. */
+static inline PyObject*
+_PyObject_INIT(PyObject *op, PyTypeObject *typeobj)
+{
+ assert(op != NULL);
+ Py_TYPE(op) = typeobj;
+ if (PyType_GetFlags(typeobj) & Py_TPFLAGS_HEAPTYPE) {
+ Py_INCREF(typeobj);
+ }
+ _Py_NewReference(op);
+ return op;
+}
+
+#define PyObject_INIT(op, typeobj) \
+ _PyObject_INIT(_PyObject_CAST(op), (typeobj))
+
+static inline PyVarObject*
+_PyObject_INIT_VAR(PyVarObject *op, PyTypeObject *typeobj, Py_ssize_t size)
+{
+ assert(op != NULL);
+ Py_SIZE(op) = size;
+ PyObject_INIT((PyObject *)op, typeobj);
+ return op;
+}
+
+#define PyObject_INIT_VAR(op, typeobj, size) \
+ _PyObject_INIT_VAR(_PyVarObject_CAST(op), (typeobj), (size))
+
+
/* This function returns the number of allocated memory blocks, regardless of size */
PyAPI_FUNC(Py_ssize_t) _Py_GetAllocatedBlocks(void);
diff --git a/Include/object.h b/Include/object.h
index 4506757d2dc8b..91855d0aa8ae1 100644
--- a/Include/object.h
+++ b/Include/object.h
@@ -233,8 +233,7 @@ PyAPI_FUNC(int) PyObject_SetAttr(PyObject *, PyObject *, PyObject *);
PyAPI_FUNC(int) PyObject_HasAttr(PyObject *, PyObject *);
PyAPI_FUNC(PyObject *) PyObject_SelfIter(PyObject *);
PyAPI_FUNC(PyObject *) PyObject_GenericGetAttr(PyObject *, PyObject *);
-PyAPI_FUNC(int) PyObject_GenericSetAttr(PyObject *,
- PyObject *, PyObject *);
+PyAPI_FUNC(int) PyObject_GenericSetAttr(PyObject *, PyObject *, PyObject *);
#if !defined(Py_LIMITED_API) || Py_LIMITED_API+0 >= 0x03030000
PyAPI_FUNC(int) PyObject_GenericSetDict(PyObject *, PyObject *, void *);
#endif
@@ -381,20 +380,8 @@ you can count such references to the type object.)
PyAPI_DATA(Py_ssize_t) _Py_RefTotal;
PyAPI_FUNC(void) _Py_NegativeRefcount(const char *filename, int lineno,
PyObject *op);
-PyAPI_FUNC(Py_ssize_t) _Py_GetRefTotal(void);
#endif /* Py_REF_DEBUG */
-/* Update the Python traceback of an object. This function must be called
- when a memory block is reused from a free list. */
-PyAPI_FUNC(int) _PyTraceMalloc_NewReference(PyObject *op);
-
-PyAPI_FUNC(void) _Py_NewReference(PyObject *op);
-
-#ifdef Py_TRACE_REFS
-/* Py_TRACE_REFS is such major surgery that we call external routines. */
-PyAPI_FUNC(void) _Py_ForgetReference(PyObject *);
-#endif
-
PyAPI_FUNC(void) _Py_Dealloc(PyObject *);
static inline void _Py_INCREF(PyObject *op)
diff --git a/Include/objimpl.h b/Include/objimpl.h
index 2337d8a56c774..45919251f43a5 100644
--- a/Include/objimpl.h
+++ b/Include/objimpl.h
@@ -127,40 +127,21 @@ PyAPI_FUNC(PyVarObject *) _PyObject_NewVar(PyTypeObject *, Py_ssize_t);
#define PyObject_NewVar(type, typeobj, n) \
( (type *) _PyObject_NewVar((typeobj), (n)) )
-/* Inline functions trading binary compatibility for speed:
- PyObject_INIT() is the fast version of PyObject_Init(), and
- PyObject_INIT_VAR() is the fast version of PyObject_InitVar.
- See also pymem.h.
-
- These inline functions expect non-NULL object pointers. */
-static inline PyObject*
-_PyObject_INIT(PyObject *op, PyTypeObject *typeobj)
-{
- assert(op != NULL);
- Py_TYPE(op) = typeobj;
- if (PyType_GetFlags(typeobj) & Py_TPFLAGS_HEAPTYPE) {
- Py_INCREF(typeobj);
- }
- _Py_NewReference(op);
- return op;
-}
-
-#define PyObject_INIT(op, typeobj) \
- _PyObject_INIT(_PyObject_CAST(op), (typeobj))
+#define _PyObject_SIZE(typeobj) ( (typeobj)->tp_basicsize )
-static inline PyVarObject*
-_PyObject_INIT_VAR(PyVarObject *op, PyTypeObject *typeobj, Py_ssize_t size)
-{
- assert(op != NULL);
- Py_SIZE(op) = size;
- PyObject_INIT((PyObject *)op, typeobj);
- return op;
-}
-#define PyObject_INIT_VAR(op, typeobj, size) \
- _PyObject_INIT_VAR(_PyVarObject_CAST(op), (typeobj), (size))
+#ifdef Py_LIMITED_API
+/* Define PyObject_INIT() and PyObject_INIT_VAR() as aliases to PyObject_Init()
+ and PyObject_InitVar() in the limited C API for compatibility with the
+ CPython C API. */
+# define PyObject_INIT(op, typeobj) \
+ PyObject_Init(_PyObject_CAST(op), (typeobj))
+# define PyObject_INIT_VAR(op, typeobj, size) \
+ PyObject_InitVar(_PyVarObject_CAST(op), (typeobj), (size))
+#else
+/* PyObject_INIT() and PyObject_INIT_VAR() are defined in cpython/objimpl.h */
+#endif
-#define _PyObject_SIZE(typeobj) ( (typeobj)->tp_basicsize )
/* _PyObject_VAR_SIZE returns the number of bytes (as size_t) allocated for a
vrbl-size object with nitems items, exclusive of gc overhead (if any). The
diff --git a/Misc/NEWS.d/next/C API/2020-02-05-12-40-51.bpo-39542.si-_Zq.rst b/Misc/NEWS.d/next/C API/2020-02-05-12-40-51.bpo-39542.si-_Zq.rst
new file mode 100644
index 0000000000000..7473577b0a943
--- /dev/null
+++ b/Misc/NEWS.d/next/C API/2020-02-05-12-40-51.bpo-39542.si-_Zq.rst
@@ -0,0 +1,7 @@
+In the limited C API, ``PyObject_INIT()`` and ``PyObject_INIT_VAR()`` are
+now defined as aliases to :c:func:`PyObject_Init` and
+:c:func:`PyObject_InitVar` to make their implementation opaque. It avoids to
+leak implementation details in the limited C API. Exclude the following
+functions from the limited C API: ``_Py_NewReference()``,
+``_Py_ForgetReference()``, ``_PyTraceMalloc_NewReference()`` and
+``_Py_GetRefTotal()``.
diff --git a/Objects/object.c b/Objects/object.c
index 1884819b982c4..43b838adff20c 100644
--- a/Objects/object.c
+++ b/Objects/object.c
@@ -139,9 +139,11 @@ Py_DecRef(PyObject *o)
PyObject *
PyObject_Init(PyObject *op, PyTypeObject *tp)
{
- if (op == NULL)
+ /* Any changes should be reflected in PyObject_INIT() macro */
+ if (op == NULL) {
return PyErr_NoMemory();
- /* Any changes should be reflected in PyObject_INIT (objimpl.h) */
+ }
+
Py_TYPE(op) = tp;
if (PyType_GetFlags(tp) & Py_TPFLAGS_HEAPTYPE) {
Py_INCREF(tp);
@@ -153,9 +155,11 @@ PyObject_Init(PyObject *op, PyTypeObject *tp)
PyVarObject *
PyObject_InitVar(PyVarObject *op, PyTypeObject *tp, Py_ssize_t size)
{
- if (op == NULL)
+ /* Any changes should be reflected in PyObject_INIT_VAR() macro */
+ if (op == NULL) {
return (PyVarObject *) PyErr_NoMemory();
- /* Any changes should be reflected in PyObject_INIT_VAR */
+ }
+
Py_SIZE(op) = size;
PyObject_Init((PyObject *)op, tp);
return op;
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