Re: [PATCH, ARM] attribute target (thumb,arm) [4/6] respin (5th)

[Christian Bruel <christian dot bruel at st dot com>]

On 06/01/2015 02:41 PM, Kyrill Tkachov wrote:
> On 01/06/15 12:29, Christian Bruel wrote:
> > hi Kyrill
> >
> >
> > On 06/01/2015 12:39 PM, Kyrill Tkachov wrote:
> > > On 18/05/15 09:14, Christian Bruel wrote:
> > > > Hi,
> > > Hi Christian,
> > > A couple comments inline.
> > > Overall, the approach looks ok to me, though I think we'll have to
> > > generalise arm_valid_target_attribute_rec in the future if we want
> > > to allow other target attributes.
> > the other fpu target attributes will be part of another set of
> > developments, specific parsing strings will be added as they are
> > implemented.
>
> Ok, so you plan on working on fpu attributes as well?

I have a prototype for fpu=neon, it works locally but there are still a 
few corner cases and testing to sort out before sending a draft.

There are so many architectural variants to check that I might ask for 
help once it is a little bit more robust, and some might be similar with 
aarch64's simd.

> > > +
> > > +/* Establish appropriate back-end context for processing the function
> > > +   FNDECL.  The argument might be NULL to indicate processing at top
> > > +   level, outside of any function scope.  */
> > > +static void
> > > +arm_set_current_function (tree fndecl)
> > > +{
> > > +  if (!fndecl || fndecl == arm_previous_fndecl)
> > > +    return;
> > > +
> > > +  tree old_tree = (arm_previous_fndecl
> > > +		   ? DECL_FUNCTION_SPECIFIC_TARGET (arm_previous_fndecl)
> > > +		   : NULL_TREE);
> > > +
> > > +  tree new_tree = DECL_FUNCTION_SPECIFIC_TARGET (fndecl);
> > > +
> > > +  arm_previous_fndecl = fndecl;
> > > +  if (old_tree == new_tree)
> > > +    ;
> > > +
> > > +  else if (new_tree)
> > > +    {
> > > +      cl_target_option_restore (&global_options,
> > > +				TREE_TARGET_OPTION (new_tree));
> > > +
> > > +      if (TREE_TARGET_GLOBALS (new_tree))
> > > +	restore_target_globals (TREE_TARGET_GLOBALS (new_tree));
> > > +      else
> > > +	TREE_TARGET_GLOBALS (new_tree)
> > > +	  = save_target_globals_default_opts ();
> > > +    }
> > > +
> > > +  else if (old_tree)
> > > +    {
> > > +      new_tree = target_option_current_node;
> > > +
> > > +      cl_target_option_restore (&global_options,
> > > +				TREE_TARGET_OPTION (new_tree));
> > > +      if (TREE_TARGET_GLOBALS (new_tree))
> > > +	restore_target_globals (TREE_TARGET_GLOBALS (new_tree));
> > > +      else if (new_tree == target_option_default_node)
> > > +	restore_target_globals (&default_target_globals);
> > > +      else
> > > +	TREE_TARGET_GLOBALS (new_tree)
> > > +	  = save_target_globals_default_opts ();
> > > +    }
> > > +
> > > +  arm_option_params_internal (&global_options);
> > >
> > >
> > > I thought the more common approach was to define TARGET_OPTION_RESTORE
> > > that was supposed to restore the backend state, including calling arm_option_params_internal?
> > > That way, cl_target_option_restore would do all that needs to be done to restore the backend.
> > TARGET_OPTION_RESTORE is fine to restore target-specific
> > information from struct cl_target_option. Other global states might as
> > well be expressed within set_current_function (e.g indeed I might use
> > TARGET_OPTION_RESTORE to switch arm_fpu_attr in the fpu neon attribute).
> > But IMHO arm_option_params_internal are fine to be called there since
> > the 2 params only depend from x_target_flags without the need of a new
> > macro.
>
> Ok, I see.
> The patch looks ok to me modulo the typo nits I pointed out, but I think Ramana
> should have the final say here as he's already started reviewing it and it adds quite
> a lot of functionality.

OK thanks, I'll wait for Ramana's final words.

Cheers

Christian

> Thanks,
> Kyrill
>
> >