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Re: [patches] Remove "nonreturn" declaration from abort
- To: David Kastrup <dak@xxxxxxx>
- Subject: Re: [patches] Remove "nonreturn" declaration from abort
- From: "Joseph S. Myers" <joseph@xxxxxxxxxxxxxxxx>
- Date: Thu, 7 May 2009 11:24:35 +0000 (UTC)
On Thu, 7 May 2009, David Kastrup wrote:
> I don't actually include a patch: it would just consist of removing the
> respective declaration from the abort call. I can't vouch that gcc
> itself has builtin "knowledge" here, too, but fixing the library
> declaration would be a first step.
The compiler does have built-in knowledge. Furthermore, thus knowledge is
important for other reasons; many bogus warnings and -Werror build
failures would result if the compiler doesn't know that execution
terminates on certain paths and so things that certain flows of control
are possible that are not possible.
I think you should add an extra attribute to the compiler to say that
certain optimizations should not be applied to calls to a particular
noreturn function, and make the compiler also put that on its built-in
declaration of abort. The compiler would still know about the control
flow effects, and just avoid those transformations that are problematic.
Joseph S. Myers