Re: [RFC 0/5] xtensa: support dynamic configuration

[Max Filippov <jcmvbkbc@gmail.com>]

Hi Nick,

On Tue, Jun 6, 2017 at 5:41 AM, Nick Clifton <nickc@redhat.com> wrote:
>> Built toolchain takes configuration
>> parameters from the shared object specified in the environment variable.
>
> Using environment variables to pass configuration information is a bad idea.
>
> The problem is that it can be very hard to debug problems when environment
> variables are involved.  Often they are not included in bug reports, which
> makes reproducing the problem tricky.
>
> At the very least you should also provide a command line option which
> specifies the path to a file containing the configuration information.  If
> specified this option should override the environment variable.

Ok, let me look at it.

> There is also the issue of versioning to consider.  Does the configuration
> information contain a version number ?  What happens if the configuration
> information is out of date with respect to the compiler/linker or if the
> tools are older than the configuration information ?

My intention was to keep versioning of each entity contained in the plugin
private to that entity users, because some users may already have some
versioning scheme. Regarding the configuration information: its structure
size is used as its version, and the structure may only be extended at its
end. Newer tools will reject using older configuration, older tools will accept
newer configuration.

-- 
Thanks.
-- Max