Re: MPS codegen

[Eli Zaretskii <eliz@gnu.org>]

> From: Helmut Eller <eller.helmut@gmail.com>
> Cc: Andrea Corallo <acorallo@gnu.org>,  Eli Zaretskii <eliz@gnu.org>,
>   emacs-devel@gnu.org
> Date: Fri, 14 Jun 2024 10:51:38 +0200
> 
> On Fri, Jun 14 2024, Gerd Möllmann wrote:
> 
> > Gerd Möllmann <gerd.moellmann@gmail.com> writes:
> >
> >> Helmut Eller <eller.helmut@gmail.com> writes:
> >>
> >>> I planned to give it a try, but not until somebody™ updates the branch
> >>> on savannah.  Otherwise patches to pdumper.c don't apply cleanly.
> >>
> >> Ok, ok, I'll give it a try now that you did the obarray and pure space
> >> thing. No pressure :-).
> >
> > By our command. Done :-).
> 
> Thanks!

Too soon to be happy: the MS-Windows 32-bit build is now broken: it
segfaults while producing loaddefs.el:

  Starting program: d:\gnu\git\emacs\feature\src\emacs.exe -batch --no-site-file --no-site-lisp -l ./emacs-lisp/loaddefs-gen.elc  -f loaddefs-generate--emacs-batch . ./calc ./calendar ./cedet ./cedet/ede ./cedet/semantic ./cedet/semantic/analyze ./cedet/semantic/bovine ./cedet/semantic/decorate ./cedet/semantic/symref ./cedet/semantic/wisent ./cedet/srecode ./emacs-lisp ./emulation ./erc ./eshell ./gnus ./image ./international ./language ./leim ./leim/ja-dic ./leim/quail ./mail ./mh-e ./net ./nxml ./org ./play ./progmodes ./textmodes ./url ./use-package ./vc
  [New Thread 30924.0x8288]
  [New Thread 30924.0x8448]
  [New Thread 30924.0x87bc]
  warning: Enabling Low Fragmentation Heap failed: error 87

  Thread 1 received signal SIGSEGV, Segmentation fault.
  do_symval_forwarding (valcontents=...) at data.c:1334
  1334      switch (XFWDTYPE (valcontents))
  (gdb) bt
  #0  do_symval_forwarding (valcontents=...) at data.c:1334
  #1  0x008a576d in specbind (symbol=<optimized out>, symbol@entry=XIL(0x53b8),
      value=value@entry=XIL(0x18)) at eval.c:3572
  #2  0x0073fb6e in message_dolog (m=<optimized out>, nbytes=<optimized out>,
      nlflag=true, multibyte=false) at lisp.h:1191
  #3  0x0074a3b0 in message_dolog (m=<optimized out>,
      m@entry=0xde85d1 <b_fwd+1597> "", nbytes=nbytes@entry=0,
      nlflag=nlflag@entry=true, multibyte=multibyte@entry=false) at xdisp.c:12216
  #4  0x00a4c0a5 in main (argc=<optimized out>, argv=<optimized out>)
      at emacs.c:2229
  (gdb) fr 2
  #2  0x008a576d in specbind (symbol=<optimized out>, symbol@entry=XIL(0x53b8),
      value=value@entry=XIL(0x18)) at eval.c:3572
  3572            Lisp_Object ovalue = find_symbol_value (symbol);
  (gdb) l
  3567          specpdl_ptr->let.where.kbd = NULL;
  3568          break;
  3569        case SYMBOL_LOCALIZED:
  3570        case SYMBOL_FORWARDED:
  3571          {
  3572            Lisp_Object ovalue = find_symbol_value (symbol);
  3573            specpdl_ptr->let.kind = SPECPDL_LET_LOCAL;
  3574            specpdl_ptr->let.symbol = symbol;
  3575            specpdl_ptr->let.old_value = ovalue;
  3576            specpdl_ptr->let.where.buf = Fcurrent_buffer ();
  (gdb) p symbol
  $1 = <optimized out>

I get basically the same segfault and backtrace if I delete
loaddefs-gen.elc and run "make"; repeating the same command under GDB
produces this:

  Starting program: d:\gnu\git\emacs\feature\src\emacs.exe -batch --no-site-file --no-site-lisp --eval "(setq load-prefer-newer t byte-compile-warnings 'all)"  --eval "(setq org--inhibit-version-check t)"  -f batch-byte-compile emacs-lisp/loaddefs-gen.el
  [New Thread 30136.0x8330]
  [New Thread 30136.0x81c8]
  [New Thread 30136.0x843c]
  warning: Enabling Low Fragmentation Heap failed: error 87

  Thread 1 received signal SIGSEGV, Segmentation fault.
  do_symval_forwarding (valcontents=...) at data.c:1334
  1334      switch (XFWDTYPE (valcontents))
  (gdb) bt
  #0  do_symval_forwarding (valcontents=...) at data.c:1334
  #1  0x008a576d in specbind (symbol=<optimized out>, symbol@entry=XIL(0x53b8),
      value=value@entry=XIL(0x18)) at eval.c:3572
  #2  0x0073fb6e in message_dolog (m=<optimized out>, nbytes=<optimized out>,
      nlflag=true, multibyte=false) at lisp.h:1191
  #3  0x0074a3b0 in message_dolog (m=<optimized out>,
      m@entry=0xde85d1 <b_fwd+1597> "", nbytes=nbytes@entry=0,
      nlflag=nlflag@entry=true, multibyte=multibyte@entry=false) at xdisp.c:12216
  #4  0x00a4c0a5 in main (argc=<optimized out>, argv=<optimized out>)
      at emacs.c:2229
  (gdb) fr 2
  #2  0x008a576d in specbind (symbol=<optimized out>, symbol@entry=XIL(0x53b8),
      value=value@entry=XIL(0x18)) at eval.c:3572
  3572            Lisp_Object ovalue = find_symbol_value (symbol);
  (gdb) p symbol
  $1 = <optimized out>
  (gdb) l
  3567          specpdl_ptr->let.where.kbd = NULL;
  3568          break;
  3569        case SYMBOL_LOCALIZED:
  3570        case SYMBOL_FORWARDED:
  3571          {
  3572            Lisp_Object ovalue = find_symbol_value (symbol);
  3573            specpdl_ptr->let.kind = SPECPDL_LET_LOCAL;
  3574            specpdl_ptr->let.symbol = symbol;
  3575            specpdl_ptr->let.old_value = ovalue;
  3576            specpdl_ptr->let.where.buf = Fcurrent_buffer ();
  (gdb) p sym
  $2 = (struct Lisp_Symbol *) 0xee7f98 <lispsym+21432>
  (gdb) p *$
  $3 = {
    u = {
      s = {
	gcmarkbit = 0,
	redirect = SYMBOL_FORWARDED,
	trapped_write = SYMBOL_UNTRAPPED_WRITE,
	interned = SYMBOL_INTERNED_IN_INITIAL_OBARRAY,
	declared_special = 1,
	pinned = 0,
	name = XIL(0xc0dbaa4),
	val = {
	  value = XIL(0x1a986958),
	  alias = 0x1a986958,
	  blv = 0x1a986958,
	  fwd = {
	    fwdptr = 0x1a986958
	  }
	},
	function = XIL(0),
	plist = XIL(0xc0dbabb),
	next = 0x0
      },
      gcaligned = -58 'Æ'
    }
  }
  (gdb) p $->name
  There is no member named name.
  (gdb) p $->u.s.name
  $4 = XIL(0xc0dbaa4)
  (gdb) xtype
  Lisp_String
  (gdb) xstring
  $5 = (struct Lisp_String *) 0xc0dbaa0
  "inhibit-modification-hooks"
  (gdb) p $->u.s.val
  There is no member named val.
  (gdb) p $2->u.s.val
  $6 = {
    value = XIL(0x1a986958),
    alias = 0x1a986958,
    blv = 0x1a986958,
    fwd = {
      fwdptr = 0x1a986958
    }
  }
  (gdb) p $2->u.s.val.value
  $7 = XIL(0x1a986958)
  (gdb) xtype
  Lisp_Symbol
  (gdb) xsymbol
  $8 = (struct Lisp_Symbol *) 0x1b869538
  Cannot access memory at address 0x1b86953c
  (gdb)

Any ideas or suggestions?  Does the current branch build on GNU/Linus
as a 32-bit executable?