Re: [PATCH] PR c/86407 - Add option to ignore fndecl attributes on function pointers

[Alex Henrie <alexhenrie24@gmail.com>]

On Fri, May 24, 2019 at 2:01 AM Richard Biener <rguenther@suse.de> wrote:
>
> I'm not sure we really need a new warning for this.

On Fri, May 24, 2019 at 9:23 AM Martin Sebor <msebor@gmail.com> wrote:
>
> I don't think GCC makes a formal distinction between function
> attributes that affect only function definitions vs those that
> affect its users, or both.  It might be a useful distinction
> to introduce, perhaps even for functions as well as variables,
> but as it is, users (as well as GCC developers) are on our own
> to figure it out.

Then is it preferable to simply silence Wattributes in this case?

On Fri, May 24, 2019 at 2:01 AM Richard Biener <rguenther@suse.de> wrote:
>
> > +int __attribute__((__ms_hook_prologue__)) func(); /* no warnings */
> > +
>
> But this is a declaration?

On Fri, May 24, 2019 at 9:23 AM Martin Sebor <msebor@gmail.com> wrote:
>
> My first question is: what is the meaning of "function definition
> attributes?"  Presumably those that affect only the definition of
> a function and not its callers or other users?

As far as I can tell, "fndecl" is a misnomer: these attributes are
more accurately called "function definition attributes", i.e.
attributes that affect the assembly code of the function but do not
affect its calling convention.

On Fri, May 24, 2019 at 9:23 AM Martin Sebor <msebor@gmail.com> wrote:
>
> Finally, with this as a prerequisite, if we decided that a warning
> like this would be useful, tests to verify that it works for all
> the definition attributes and not for the rest would need to be
> added (i.e., in addition to ms_hook_prologue).

Okay, I will add tests for the other function attributes that should
behave in the same way, commenting out the tests that will require
more work to pass.

The end goal is to include __ms_hook_prologue__ in the WINAPI macro on
Wine without causing spurious warnings. This will go a long way
towards making Wine compatible with current and future Windows
programs. Thank you for help.

-Alex