On Tue, Jun 16, 2015 at 3:38 PM, Martin Liška <mli...@suse.cz> wrote:
> On 06/16/2015 03:17 PM, Richard Biener wrote:
>> On Tue, Jun 16, 2015 at 11:26 AM, Martin Liška <mli...@suse.cz> wrote:
>>> On 06/15/2015 07:31 PM, Marc Glisse wrote:
>>>> On Mon, 15 Jun 2015, Martin Liška wrote:
>>>>
>>>>> Ah, I overlooked that it's not a placement new, but just static casting.
>>>>> Anyway, if I added:
>>>>>
>>>>> cselib_val () {}
>>>>>
>>>>> to struct cselib_val and changed the cast to placement new:
>>>>> char *ptr = (char *) header;
>>>>> return new (ptr) T ();
>>>>>
>>>>> I got following compilation error:
>>>>>
>>>>> In file included from ../../gcc/alias.c:46:0:
>>>>> ../../gcc/alloc-pool.h: In instantiation of ‘T*
>>>>> pool_allocator<T>::allocate() [with T = cselib_val]’:
>>>>> ../../gcc/cselib.h:51:27: required from here
>>>>> ../../gcc/alloc-pool.h:416:23: error: no matching function for call to
>>>>> ‘cselib_val::operator new(sizetype, char*&)’
>>>>> return new (ptr) T ();
>>>>> ^
>>>>> In file included from ../../gcc/alias.c:47:0:
>>>>> ../../gcc/cselib.h:49:16: note: candidate: static void*
>>>>> cselib_val::operator new(size_t)
>>>>> inline void *operator new (size_t)
>>>>> ^
>>>>> ../../gcc/cselib.h:49:16: note: candidate expects 1 argument, 2 provided
>>>>
>>>> #include <new>
>>>>
>>>
>>> Hi.
>>>
>>> <new> header file is not missing (explicit addition of the file does not
>>> help).
>>> Feel free to play with following patch which should fix cselib.h
>>> compilation error.
>>
>> cselib_val overrides the new operator but fails to provide an overload
>> for the placement new
>> form. Fix that and it should work (of course it gets quite awkward
>> with its 'new' calling
>> pool.allocate and its placement new doing value-construction then...)
>>
>> Richard.
>
> Do you mean Richard following changes:
>
> alloc-pool.h (allocate):
> ...
> + /* Placement new contructor. */
> + inline void *operator new (size_t, elt_loc_list *&ptr)
> + {
> + return ptr;
> + }
That should be there with including <new>
> and e.g. cselib.h:
>
> struct cselib_val
> {
> /* Pool allocation new operator. */
> inline void *operator new (size_t)
> {
> return pool.allocate ();
> }
>
> /* Placement new contructor. */
> inline void *operator new (size_t, char *&ptr)
> {
> return ptr;
> }
Yes, though I wonder whether cselib_val should really have undefined
contents after
allocating it? (or does the pool allocator zero the memory?)
Richard.
> }
>
> Thanks,
> Martin
>
>
>
>>
>>> Thanks,
>>> Martin
>
