Java: add flag_use_atomic_builtins

[Andrew Haley]

Paolo Bonzini wrote:
> On 08/12/2009 06:52 PM, Andrew Haley wrote:
>> Joseph S. Myers wrote:
>>> On Wed, 12 Aug 2009, Andrew Haley wrote:
>>>
>>>> Some targets, particularly ARM, don't have instructions for things
>>>> such as sync_compare_and_swap.  Instead, a routine in libgcc is
>>>> used.  This patch adds a new gcj option, -fuse-atomic-builtins,
>>>> which causes gcj to use the routines in libgcc whenever atomic
>>>> operations are needed.
>>> Wouldn't a target hook to allow a target to declare which operations it
>>> provides in libgcc be better than a command-line option?
>>
>> Maybe it would.  I'm happy to work with anyone to create such a
>> thing.  What would such a hook look like, and how would a front-
>> end use it?
> 
> Couldn't optabs be (re)used?

That would be nice.

Andrew.