Re: emacs-module.c, eassert, and nonnull args

[Paul Eggert <eggert@cs.ucla.edu>]

Philipp Stephani wrote:
> Here's a new patch. It makes this change, and also changes the allocation
> slightly so that objects have unique addresses (useful for checking).

Thanks for working on this. Some comments.

Have you looked into the runtime overhead of this approach, assuming 
-module-assertions is not specified? Currently lisp_to_value and value_to_lisp 
typically  are optimized away (i.e., zero machine instructions), and that 
wouldn't be true under the proposed patch even when -module-assertions is not 
used. Granted, module calls need not be super-fast, but it might be nice to 
avoid the overhead in the typical case if that is easy.

What happens if -module-assertions is enabled for Emacs, Emacs dumps itself, and 
-module-assertions is not enabled when the dumped Emacs is run? Or vice versa.

Are the FOR_EACH_TAIL_SAFE macro calls needed? This macro is needed only for 
lists that might be circular (e.g., the lists are available to Lisp code, which 
can call setcdr on their components). If the calls are not needed I suggest just 
an ordinary for loop.

A small point: the FOR_EACH... loops should be indented like ordinary for-loops.