Hi,
The previous email is about this problem of Emacs.app not working when
dumped under GNUstep. Since I cannot work on this myself at the
moment (and failed when I *did* put time into it before), let me
provide the background of what I know. What happens is this: emacs
loads into memory, then performs a bunch of initialization (mainly
reading/interpreting elisp files), then dumps its in-memory executable
+data image out to disk. In the future, this becomes the new
executable, the idea being that you then are up and running without
having to perform the initialization.
Something in this causes a failure under GNUstep (trace below). I'm
not sure if it's a problem with the emacs dump code or with
initialization in the GNUstep runtime, but I think there is some more
that can be tried on the emacs side codewise, though it would be best
done by someone acquainted with GNUstep memory handling.
The thing to look at is the difference between unexmacosx.c and, e.g.,
unexelf.c. It seems that some special handling for memory allocation
may be needed. In unexmacosx, we read in the comments:
The Mac OS X implementation of unexec makes use of Darwin's `zone'
memory allocator. All calls to malloc, realloc, and free in Emacs
are redirected to unexec_malloc, unexec_realloc, and unexec_free in
this file. When temacs is run, all memory requests are handled in
the zone EmacsZone. The Darwin memory allocator library calls
maintain the data structures to manage this zone. Dumping writes
its contents to data segments of the executable file. When emacs
is run, the loader recreates the contents of the zone in memory.
However since the initialization routine of the zone memory
allocator is run again, this `zone' can no longer be used as a
heap. That is why emacs uses the ordinary malloc system call to
allocate memory. Also, when a block of memory needs to be
reallocated and the new size is larger than the old one, a new
block must be obtained by malloc and the old contents copied to
it.
It is possible that adding this sort of logic to unexelf will solve
the problem. Note there are also some #defines in darwin.h that would
need to be replicated in gnu-linux.h or whatever system is being
compiled on. Because emacs plays a number of games with malloc on
different systems (search for "Doug Leah" in the code and configure
scripts) there may be more to be done than straight copy-paste.
If there is still a failure after this is tried, there may be a gnu-
apple difference in the runtime or how the foundation library
initializes. But we can't be sure about this until unexelf under
GNUstep does everything that unexmacosx does.
-Adrian
_______________________________________________
Gnustep-dev mailing list
[email protected]
http://lists.gnu.org/mailman/listinfo/gnustep-dev
