> It looks like Tim managed to work some magic and make pymalloc's free
> handle memory allocated by either the system allocator or pymalloc
> itself. That means we can make PyMem_DEL use the pymalloc's 'free' and
> make PyObject_NEW use pymalloc's 'malloc'. Here's my plan for making
> this happen:
>
> #define PyMem_MALLOC(n) malloc(n)
> #define PyMem_REALLOC(p, n) realloc((void *)(p), (n))
> #define PyMem_FREE(p) free((void *)(p))
+1
> I think making PyMem_FREE call free() is safe. I haven't seen any
> extension modules allocate with PyObject_NEW and free with PyMem_FREE.
> We deprecate the PyMem_* functions. There's no need for them, IMHO:
>
> #define PyMem_Malloc PyMem_MALLOC
> #define PyMem_New PyMem_NEW
> #define PyMem_Resize PyMem_RESIZE
> #define PyMem_Free PyMem_DEL
> #define PyMem_Del PyMem_DEL
> /* See comment near MALLOC_ZERO_RETURNS_NULL in pyport.h. */
> #define PyMem_Realloc(p, n) \
> do { \
> size_t _n = n; \
> PyMem_REALLOC(p, _n ? _n : 1); \
> } while (0)
+1
> Next, we base PyObject_{MALLOC,REALLOC,FREE} on pymalloc. Basically:
>
> #ifdef WITH_PYMALLOC
> #define PyObject_MALLOC(n) _PyMalloc_Malloc(n)
> #define PyObject_REALLOC(op, n) _PyMalloc_Realloc((void *)(op), (n))
> #define PyObject_FREE(op) _PyMalloc_Free((void *)(op))
> #else
> #define PyObject_MALLOC(n) PyMem_MALLOC(n)
> #define PyObject_REALLOC(op, n) PyMem_REALLOC((void *)(op), (n))
> #define PyObject_FREE(op) PyMem_FREE((void *)(op))
> #endif
Couldn't these always use the first set of definitions? I suppose
that when configured --without-pymalloc, _PyMalloc_Malloc and friends
are aliases for malloc?
Also, do we need these at all? (Hm, I must be missing something, but
I can't figure what.)
> PyMem_DEL and PyMem_Free need to call pymalloc:
>
> #define PyMem_DEL(op) PyObject_FREE(op)
Why not _PyMalloc_Malloc?
> We go through the source and replace all the PyMem_* function calls with
> the equivalent PyMem_* macro calls and replace PyMem_DEL with
> PyMem_FREE.
Or PyObject_Del (depending on the situation)?
> The recommended API for extension modules writers would be
> PyMem_{MALLOC,REALLOC,NEW,RESIZE,FREE}, PyObject_{New,NewVar,Del}, and
> PyObject_GC_{New,NewVar,Del}.
Is there a difference between PyMem_MALLOC and PyMem_NEW? Between
PyMem_REALLOC and PyMem_RESIZE? If there isn't, shouldn't we
recommend one set and deprecate the other? I think I like the NEW
family best (it's got seniority).
I suppose the patches that changed PyObject_New into PyMalloc_New can
be reverted now?
Finally, there still seem to be too many macros and functions. But
it's better than before!
--Guido van Rossum (home page: http://www.python.org/~guido/)
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