Re: MPS: assertion failed: header_type (h) != IGC_OBJ_FWD

["Gerd Möllmann" <gerd.moellmann@gmail.com>]

Eli Zaretskii <eliz@gnu.org> writes:

>> From: Gerd Möllmann <gerd.moellmann@gmail.com>
>> Cc: Emacs Devel <emacs-devel@gnu.org>,  Helmut Eller <eller.helmut@gmail.com>
>> Date: Tue, 16 Jul 2024 15:02:24 +0200
>> 
>> The handlerlist_sentinel didn't help, BTW, but I had another idea today.
>> The function scan_ambig assumes that that references are aligned on word
>> boundaries (8 bytes here). I haven't checked (and I'm too lazy to check
>> :-)), but that assumption doesn't have to be true.
>
> I think it _is_ true.  At least the original allocation code in
> alloc.c made sure it was true.  Paul, am I right?

That's probably a misunderstanding. I'm thinking about a block of memory
containing references, and the alignment of these references, not the
alignment of the block.

Example with sizeof(int) = 4, and sizeof(void *) = 8

  struct x
  {
    int x;
    struct Lisp_Symbol *s;
  };

What about the offset of x::s?