Re: Java: add flag_use_atomic_builtins

[Andrew Haley <aph@redhat.com>]

Andrew Haley wrote:
> 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.

I guess that's just a matter of

  set_optab_libfunc (sync_compare_and_swap_optab, SImode,, SImode, SImode "__sync_bool_compare_and_swap_4");

or somesuch?

Andrew.