Re: [PATCH 1/2] Remove noreturn function pointers in usage.c

From: Andi Kleen <andi@firstfloor.org>
Date: Jun 9, 2011, 04:59 UTC
Message-ID: <20110609045915.GA15448@one.firstfloor.org>
In-Reply-To: <7v4o3z264s.fsf@alter.siamese.dyndns.org>

Show 5 quoted lines

>  - There are many more NORETURN and NORETURN_PTR in the code, and the
>    proposed commit log message does not explain why these two are the only
>    ones that are problematic and needs to be worked around. It does not
>    guide other people who might want to add NORETURN/NORETURN_PTR when
>    deciding if their change would break the "fix" this change brought in.

This was the only place where it crashed the compiler.

I don't have a good criterium to decide which cases do crash the compiler or not except for trying it.

But I believe the crash is relatively unlikely (needs quite a lot of conditions to line up), so it doesn't deserve extensive changes all over.

> 
>  - Potential impact to people who do not use Gcc 4.6 with profile feedback
>    is not explained away well, except for "Doesn't seem to make any
>    difference."

I merely went by "there are no new warnings" (I assume that's the main motivation)

Show 6 quoted lines

> 
>  - If other NORETURN/NORETURN_PTR could/should also go (I don't know due
>    to the first bullet point above) when using the problematic compiler
>    with the profile feedback feature, wouldn't it be a better workaround
>    would be to introduce a Makefile variable to ask git-compat-util.h to
>    make these two a no-op, perhaps?

I don't think we need to remove the others for now.

Show 6 quoted lines

> 
> A patch to do so may look like this.
> 
> I did not like the triple negation "make NO_NORETURN=NoThanks" and wanted
> to name this AVOID_NORETURN instead, but decided to go with other existing
> Makefile variables.

Given the explanation above (I can update the description with that) do you still want the complete disabling?

-Andi