[PATCH 005/236] Introduce as_a_nullable

[Jeff Law]

On 08/13/14 04:07, Richard Biener wrote:
> On Wed, Aug 13, 2014 at 12:01 PM, Martin Jambor <mjambor@suse.cz> wrote:
>> Hi,
>>
>> On Wed, Aug 06, 2014 at 01:19:44PM -0400, David Malcolm wrote:
>>> In many circumstances, is_a_helper <T>::test assumes that the pointer is
>>> non-NULL, but sometimes you have a pointer of type T that can be NULL.
>>>
>>> Earlier versions of this patch kit made numerous uses of the ternary
>>> operator to handle nullable pointers e.g.:
>>>
>>>    return insn ? as_a <rtx_insn *> (insn) : NULL;
>>>
>>> but this was ugly.  Instead, introduce an as_a_nullable<T> variant that
>>> adds a check for NULL, so the above can be written simply as:
>>>
>>>    return as_a_nullable <rtx_insn *> (insn);
>>
>> A tiny bikeshedding, disregard it if you don't like it: however, the
>> "nullable" part of the name suggests the pointer can be NULLed in the
>> process.  I think that variants of functions that survive NULL
>> arguments are traditionally called "safe" in gcc, so what about
>> "safe_as" (or safely_as)?
>
> Ok, I resisted at first starting the bike-shedding but I agree on
> the badness of "nullable" (what does that mean anyway?).
> as_a_safe or safe_as_a both work for me.
Then let's go with that.

David, pick one of those and adjust accordingly.  Hopefully the cases 
where you have to adjust aren't too many.

Adjusting any patch already approved with the name change is pre-approved.


jeff