Re: [PATCH] untyped calls: enable target switching [PR112334]

[Jeff Law <jeffreyalaw@gmail.com>]

On 12/1/23 08:10, Alexandre Oliva wrote:
> On Dec  1, 2023, Alexandre Oliva <oliva@adacore.com> wrote:
> 
>> Also tested on arm-eabi, but it's *not* enough (or needed) to fix the
>> PR, there's another bug lurking there, with a separate patch coming
>> up.
> 
> Here it is.
> 
> ----
> 
> The computation of apply_args_size and apply_result_size is saved in a
> static variable, so that the corresponding _mode arrays are
> initialized only once.  That is not compatible with switchable
> targets, and ARM's arm_set_current_function, by saving and restoring
> target globals, exercises this problem with a testcase such as that in
> the PR, in which more than one function in the translation unit calls
> __builtin_apply or __builtin_return, respectively.
> 
> This patch moves the _size statics into the target_builtins array,
> with a bit of ugliness over _plus_one so that zero initialization of
> the struct does the right thing.
> 
> Regstrapped on x86_64-linux-gnu, tested on arm-eabi with and without the
> upthread patch.  It fixes the hardcfr fails either way.  As for the
> ugliness, there's a follow up patch below that attempts to alleviate it
> a little (also regstrapped and tested), but I'm not sure we want to go
> down that path.  WDYT?
It's a wart, but doesn't seem too bad to me.

> 
> 
> for  gcc/ChangeLog
> 
> 	PR target/112334
> 	* builtins.h (target_builtins): Add fields for apply_args_size
> 	and apply_result_size.
> 	* builtins.cc (apply_args_size, apply_result_size): Cache
> 	results in fields rather than in static variables.
> 	(get_apply_args_size, set_apply_args_size): New.
> 	(get_apply_result_size, set_apply_result_size): New.
OK.


> 
> untyped calls: use wrapper class type for implicit plus_one
> 
> Instead of get and set macros to apply a delta, use a single macro
> that resorts to a temporary wrapper class to apply it.
> 
> To be combined (or not) with the previous patch.
I'd be OK with this as well.

jeff