Re: lto: from insert_attributes to file_end?

Georg-Johann Lay via Gcc <[email protected]> writes:

> Am 05.05.26 um 19:05 schrieb Richard Biener:
>> On Tue, May 5, 2026 at 5:41 PM Georg-Johann Lay via Gcc <[email protected]> wrote:
>>>
>>> In the avr backend there is a static variable avr_no_call_main_p that
>>> is set in TARGET_INSERT_ATTRIBUTES and used in TARGET_ASM_FILE_END.
>>>
>>> This works as expected in non-LTO compilations, with LTO however,
>>> TARGET_INSERT_ATTRIBUTES runs in cc1[plus] but TARGET_ASM_FILE_END
>>> is run by lto1, hence the variable is not set as expected.
>>>
>>> What's the recommended way to handle such a situation?
>> Without looking too closely I assume there's an actual attribute
>> somewhere
>> (on the main function decl?).  Instead of using a global variable you'd
>> check for the presence of the attribute.  Now - the question is whether
>> the TARGET_ASM_FILE_END behavior is only required in the TU with
>> the main() definition?  In that case this should work.
>
> What works is to attach a new attribute to main when the conditions are
> right, then check for that attribute in, say,
> TARGET_DECLARE_FUNCTION_NAME and set a variable accordingly, and then
> check for that var in TARGET_ASM_FILE_END.
>
> What's a bit ugly is that it requires a new target attribute that's only
> for internal usage and should not to be set by the user.  Maybe not
> document it is okay then.
>
> Is there some policy for such internal-use-only function attributes?

I believe we do " name".

>
> Johann
>
>> I see you emit a special symbol conditional so what you can also do is
>> create that as a global variable in the symbol table and rely on the middle-end
>> to output it.

-----BEGIN PGP SIGNATURE-----

iQEBBAEWCgCpFiEEJaa7iN2bdkxrVUHCc4QJ9SDfkZAFAmn6UCUbFIAAAAAABAAO
bWFudTIsMi41KzEuMTIsMiwyXxSAAAAAAC4AKGlzc3Vlci1mcHJAbm90YXRpb25z
Lm9wZW5wZ3AuZmlmdGhob3JzZW1hbi5uZXQyNUE2QkI4OEREOUI3NjRDNkI1NTQx
QzI3Mzg0MDlGNTIwREY5MTkwDxxzYW1AZ2VudG9vLm9yZwAKCRBzhAn1IN+RkJUH
AQDgpAnbYRl1Ts2U55gLltB1MM4bhwXuQMZd4aTFv+25LwD/XxJyeaV+dS/dk5fo
L+qVWfZl4JaUId8mER6ngr4nUQI=
=2OQh
-----END PGP SIGNATURE-----