PR/15448: add a compiler timestamp to PCH files (take 2)

[Paul Brook]

On Thursday 17 February 2005 13:26, Paolo Bonzini wrote:
> > I think this solves the problem nicely, and fixes the bootstrap
> > problem.  The only other issue I can think of, is, it is critical (for
> > the installation of the libstdc++ gch file) that the install process
> > leaves the mtime alone on the compiler binary.  touch -r might be
> > necessary to make it work.  touch -r isn't very portable.
>
> The PCH would need to be rebuilt upon installation, or the st_size could
> be used alone.  The approach of checking addresses are unreliable
> because of PIE.

Is the size reliable? It's quite common for binaries to be stripped during 
installation. The only thing I can thing of that should be unmodified is the 
*relative* addresses of certain key functions.

Paul