source version info

>  
> Hi All,
>
>     in building up to the VM releases for 4.2 I would like to add meaningful
> source info to all VMs in a consistent way.  The main rationale here is to
> know exactly what source a VM was built from so that there's a chance of
> recreating it, hence to be able to use gdb-style debugging tools against
> source, and reduced chance of putting out different VMs that answer the same
> version info.
>
> There are two elements to the source info.  One is the VMMaker package.
>  This is in the Cog VMs in getSystemAttribute: 1007 (Interpreter class) and
> getSystemAttribute: 1008 (Cogit class, if any).  But there's no similar
> specific info for the ensure VM source (platform tree, and
> hopefully generated source aincluded in it).  Rather than just provide a
> revision in whatever version control system we're using I'd like us to use a
> url and a version identifier, e.g. "
> http://www.squeakvm.org/svn/squeak/branches/Cog 2359".  This could be
> getSystemAttribute: 1009 but that would probably break code that enumerates
> attributes until it gets an empty one since the StackInterpreter and
> Interpreter don;t have a Cogit class.  So, if there's agreement on including
> the url/version I would make that 1007 and move the Interpreter class and
> Cogit class to 1008 and 1009 respectively.   Since various version control
> systems don't necessarily provide a convenient way to derive the version
> info I suggest we modify the build system to include a file that is not
> included in the source tree that nas to be manually edited to contain the
> relevant string.  We can then provide helpful info close to the error
> location (when one tries to compile the file when its missing) that explain
> how to fill in the file.  (better ideas?)
>
> Also, the three platforms define their version info SQ_VERSION and
> VM_VERSION in different places and using different mechanisms, which makes
> it hard to keep things consistent.  I'd like to see these defined in
> platforms/Cross/vm/ something (platforms/Cross/vm/sqVersion.h
> ? platforms/Cross/vm/sq.h?).  SQ_VERSION appears to be unused so I'm nuking
> it from the Cog sources.  Does this make sense?
>
>
> best
> Eliot