[Vm-dev] mantis http://bugs.squeak.org/view.php?id=7349

David T. Lewis lewis at mail.msen.com
Fri May 8 02:53:21 UTC 2009

On Wed, May 06, 2009 at 10:15:11PM -0700, Andreas Raab wrote:
> Second, there is a higher level notion of whether something is 
> compatible or not - for example the return value from certain functions 
> change in a 64 bit image accordingly (I don't even know how a 32 bit 
> plugin is prevented from interacting with a 64 bit image today).

There is nothing to prevent this interaction. In order to confirm the
obvious, I copied a UnixOSProcessPlugin compiled for a 64-bit image
into the directory containing plugins for a 32-bit image. The plugin
loads and runs. A primitive that does not involve stack operations 
(primitiveGetPid) works fine. Other primitives that need to access
the stack result in a VM crash as you might expect.

In practice I have never encountered a case in which I accidentally
mixed a plugin for 64-bit images with a VM for 32-bit images (or vice
versa). I'm sure it's possible, but it has never happened to me, so
this may a problem analogous to 'Smalltalk become: nil' for which
the solution is "don't do that".


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