Re: MPS: native comp

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

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Gerd Möllmann <gerd.moellmann@gmail.com> writes:

> That promises to become fun :-/

Sometimes one needs a bit of luck. Another try landed me in an abort in
set_internal, and I could see that we have another case of a symbol
pointing to a tombstone. So, we have another reference in the
compilation unit that we don't trace.

@Andrea: Any intuition where else references could lurk, perhaps? I'm
currently doing this:

static mps_res_t
fix_comp_unit (mps_ss_t ss, struct Lisp_Native_Comp_Unit *u)
{
  MPS_SCAN_BEGIN (ss)
  {
    IGC_FIX_CALL_FN (ss, struct Lisp_Vector, u, fix_vectorlike);
    if (u->data_imp_relocs)
      {
	size_t n = ASIZE (u->data_impure_vec);
	IGC_FIX12_NOBJS (ss, u->data_imp_relocs, n);
      }
    if (u->data_relocs)
      {
	size_t n = ASIZE (u->data_vec);
	IGC_FIX12_NOBJS (ss, u->data_relocs, n);
      }
  }
  MPS_SCAN_END (ss);
  return MPS_RES_OK;
}

Maybe there's something wrong with that (the ASIZEs maybe?)

@Eli & Helmut ainly: I'm attaching my debug log because this is one of
the cases I mentioned where I needed xpostmortem to remove MPS'
barriers. xpostmortem is a command that I defined for LLDB that called
igc_postmortem.


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:PROPERTIES:
:ID:       544E65F2-9EED-4D0E-812F-79205DA0040F
:END:
#+title: Debugging Ideas
* Eager macro expansion failure, abort, ...

macroexp native-compiled, rest source. Dumnping.

#+begin_src sh
Loading /Users/gerd/emacs/savannah/igc/lisp/indent.el (source)...
Loading /Users/gerd/emacs/savannah/igc/lisp/emacs-lisp/cl-generic.el (source)...
Loading /Users/gerd/emacs/savannah/igc/lisp/simple.el (source)...

Error: error ("Eager macro-expansion failure: (setting-constant byte-compile-form-stack)")
  signal(error ("Eager macro-expansion failure: (setting-constant byte-compile-form-stack)"))
  error("Eager macro-expansion failure: %S" (setting-constant byte-compile-form-stack))
  internal-macroexpand-for-load((defalias 'undo #'(lambda (&optional arg) "Undo some previous changes.\nRepeat this command to undo more changes.\nA numeric ARG serves as a repeat count.\n\nIn Transient Mark mode when the mark is active, undo changes only within\nthe current region.  Similarly, when not in Transient Mark mode, just \\[universal-argument]\nas an argument limits undo to changes within the current region." (interactive "*P") (let* ((modified (buffer-modified-p)) (base-buffer (or (buffer-base-buffer) (current-buffer))) (recent-save (with-current-buffer base-buffer (recent-auto-save-p))) (inhibit-region (and (symbolp last-command) (get last-command 'undo-inhibit-region))) message) (setq this-command 'undo-start) (unless (and (eq last-command 'undo) (or (eq pending-undo-list t) (undo--last-change-was-undo-p buffer-undo-list))) (setq undo-in-region (and (or (region-active-p) (and arg (not (numberp arg)))) (not inhibit-region))) (if undo-in-region (undo-start (region-beginning) (region-end)) (undo-start)) (undo-more 1)) (setq this-command 'undo) (let ((equiv (gethash pending-undo-list undo-equiv-table))) (or (eq (selected-window) (minibuffer-window)) (setq message (format "%s%s" (if (or undo-no-redo (not equiv)) "Undo" "Redo") (if undo-in-region " in region" "")))) (when (and (consp equiv) undo-no-redo) (while (let ((next (gethash equiv undo-equiv-table))) (if next (setq equiv next)))) (setq pending-undo-list (if (consp equiv) equiv t)))) (undo-more (if (numberp arg) (prefix-numeric-value arg) 1)) (let ((list buffer-undo-list)) (while (eq (car list) nil) (setq list (cdr list))) (puthash list (cond (undo-in-region 'undo-in-region) ((eq list pending-undo-list) (or (gethash list undo-equiv-table) 'empty)) (t pending-undo-list)) undo-equiv-table)) (let ((tail buffer-undo-list) (prev nil)) (while (car tail) (when (integerp (car tail)) (let ((pos (car tail))) (if prev (setcdr prev (cdr tail)) (setq buffer-undo-list (cdr tail))) (setq tail (cdr tail)) (while (car tail) (if (eq pos (car tail)) (if prev (setcdr prev (cdr tail)) (setq buffer-undo-list (cdr tail))) (setq prev tail)) (setq tail (cdr tail))) (setq tail nil))) (setq prev tail tail (cdr tail)))) (and modified (not (buffer-modified-p)) (with-current-buffer base-buffer (delete-auto-save-file-if-necessary recent-save))) (if message (message "%s" message))))) t)
  eval-buffer(#<buffer  *load*> nil "/Users/gerd/emacs/savannah/igc/lisp/simple.el" nil t)
  (if eval-function (funcall eval-function buffer (if dump-mode file fullname)) (eval-buffer buffer nil (if dump-mode file fullname) nil t))
  (let ((read-symbol-shorthands shorthands)) (if eval-function (funcall eval-function buffer (if dump-mode file fullname)) (eval-buffer buffer nil (if dump-mode file fullname) nil t)))
  (let ((load-true-file-name fullname) (load-file-name fullname) (set-auto-coding-for-load t) (inhibit-file-name-operation nil) shorthands) (with-current-buffer buffer (set-buffer-multibyte t) (let (deactivate-mark) (insert-file-contents fullname)) (setq shorthands (and hack-read-symbol-shorthands-function (funcall hack-read-symbol-shorthands-function))) (if (and enable-multibyte-characters (or (eq (coding-system-type last-coding-system-used) 'raw-text))) (set-buffer-multibyte nil)) (set-buffer-modified-p nil)) (let ((read-symbol-shorthands shorthands)) (if eval-function (funcall eval-function buffer (if dump-mode file fullname)) (eval-buffer buffer nil (if dump-mode file fullname) nil t))))
  (unwind-protect (let ((load-true-file-name fullname) (load-file-name fullname) (set-auto-coding-for-load t) (inhibit-file-name-operation nil) shorthands) (with-current-buffer buffer (set-buffer-multibyte t) (let (deactivate-mark) (insert-file-contents fullname)) (setq shorthands (and hack-read-symbol-shorthands-function (funcall hack-read-symbol-shorthands-function))) (if (and enable-multibyte-characters (or (eq (coding-system-type last-coding-system-used) 'raw-text))) (set-buffer-multibyte nil)) (set-buffer-modified-p nil)) (let ((read-symbol-shorthands shorthands)) (if eval-function (funcall eval-function buffer (if dump-mode file fullname)) (eval-buffer buffer nil (if dump-mode file fullname) nil t)))) (let (kill-buffer-hook kill-buffer-query-functions) (kill-buffer buffer)))
  (let ((buffer (generate-new-buffer " *load*")) (load-in-progress t) (source (string-suffix-p ".el" fullname))) (unless nomessage (if source (message "Loading %s (source)..." file) (message "Loading %s..." file))) (when purify-flag (push (purecopy file) preloaded-file-list)) (unwind-protect (let ((load-true-file-name fullname) (load-file-name fullname) (set-auto-coding-for-load t) (inhibit-file-name-operation nil) shorthands) (with-current-buffer buffer (set-buffer-multibyte t) (let (deactivate-mark) (insert-file-contents fullname)) (setq shorthands (and hack-read-symbol-shorthands-function (funcall hack-read-symbol-shorthands-function))) (if (and enable-multibyte-characters (or (eq (coding-system-type last-coding-system-used) 'raw-text))) (set-buffer-multibyte nil)) (set-buffer-modified-p nil)) (let ((read-symbol-shorthands shorthands)) (if eval-function (funcall eval-function buffer (if dump-mode file fullname)) (eval-buffer buffer nil (if dump-mode file fullname) nil t)))) (let (kill-buffer-hook kill-buffer-query-functions) (kill-buffer buffer))) (do-after-load-evaluation fullname) (unless (or nomessage noninteractive) (if source (message "Loading %s (source)...done" file) (message "Loading %s...done" file))) t)
  (if (null (file-readable-p fullname)) (and (null noerror) (signal 'file-error (list "Cannot open load file" file))) (let ((buffer (generate-new-buffer " *load*")) (load-in-progress t) (source (string-suffix-p ".el" fullname))) (unless nomessage (if source (message "Loading %s (source)..." file) (message "Loading %s..." file))) (when purify-flag (push (purecopy file) preloaded-file-list)) (unwind-protect (let ((load-true-file-name fullname) (load-file-name fullname) (set-auto-coding-for-load t) (inhibit-file-name-operation nil) shorthands) (with-current-buffer buffer (set-buffer-multibyte t) (let (deactivate-mark) (insert-file-contents fullname)) (setq shorthands (and hack-read-symbol-shorthands-function (funcall hack-read-symbol-shorthands-function))) (if (and enable-multibyte-characters (or (eq (coding-system-type last-coding-system-used) 'raw-text))) (set-buffer-multibyte nil)) (set-buffer-modified-p nil)) (let ((read-symbol-shorthands shorthands)) (if eval-function (funcall eval-function buffer (if dump-mode file fullname)) (eval-buffer buffer nil (if dump-mode file fullname) nil t)))) (let (kill-buffer-hook kill-buffer-query-functions) (kill-buffer buffer))) (do-after-load-evaluation fullname) (unless (or nomessage noninteractive) (if source (message "Loading %s (source)...done" file) (message "Loading %s...done" file))) t))
  load-with-code-conversion("/Users/gerd/emacs/savannah/igc/lisp/simple.el" "/Users/gerd/emacs/savannah/igc/lisp/simple.el" nil nil)
  load("simple")
  load("loadup.el")
Eager macro-expansion failure: (setting-constant byte-compile-form-stack)
#+end_src

C-h v

#+begin_src sh
byte-compile-form-stack is a variable defined in ‘macroexp.el’.
#+end_src

At least suspicious that it is in macroexp which is native cpmpiled.

* Abort in set_internal

#+begin_src sh
(lldb) p *sym
(Lisp_Symbol) {
  u = {
    s = {
      gcmarkbit = false
      redirect = SYMBOL_PLAINVAL
      trapped_write = SYMBOL_NOWRITE | SYMBOL_TRAPPED_WRITE
      interned = SYMBOL_INTERNED | SYMBOL_INTERNED_IN_INITIAL_OBARRAY
      declared_special = true
      pinned = true
      name = 0x000000010f0f1614 (struct Lisp_String *) $4 = 0x000000010f0f1610
      val = {
        value = 0x0000000110623fe3 (struct Lisp_Cons *) $5 = 0x0000000110623fe0
        alias = 0x0000000110623fe3
        blv = 0x0000000110623fe3
        fwd = (fwdptr = 0x0000000110623fe3)
      }
      function = NULL
      plist = 0x000000010f0f163b (struct Lisp_Cons *) $6 = 0x000000010f0f1638
      next = 0x000000010f0f1650
    }
    gcaligned = '\xf8'
  }
}
(lldb) p *$4
error: Couldn't apply expression side effects : Couldn't dematerialize a result variable: couldn't read its memory
(lldb) p *(struct igc_header *) client_to_base (sym)
(struct igc_header)  (obj_type = IGC_OBJ_FWD, pvec_type = PVEC_FREE, hash = 1074169, nwords = 7)
#+end_src

Same procedure as last year, Miss Sophie. Symbol points to tombstone.

#+begin_src sh
(lldb) p *(struct igc_header *) 0x000000010f8619f8
(struct igc_header)  (obj_type = IGC_OBJ_SYMBOL, pvec_type = PVEC_FREE, hash = 1074169, nwords = 7)
(lldb) p *(struct Lisp_Symbol *) base_to_client ((void *)0x000000010f8619f8)
(struct Lisp_Symbol) {
  u = {
    s = {
      gcmarkbit = false
      redirect = SYMBOL_PLAINVAL
      trapped_write = SYMBOL_UNTRAPPED_WRITE
      interned = SYMBOL_INTERNED_IN_INITIAL_OBARRAY
      declared_special = true
      pinned = false
      name = 0x000000010f0f1614 (struct Lisp_String *) $9 = 0x000000010f0f1610
      val = {
        value = 0x000000010f864efb (struct Lisp_Cons *) $10 = 0x000000010f864ef8
        alias = 0x000000010f864efb
        blv = 0x000000010f864efb
        fwd = (fwdptr = 0x000000010f864efb)
      }
      function = NULL
      plist = 0x000000010f0f163b (struct Lisp_Cons *) $11 = 0x000000010f0f1638
      next = 0x000000010f0f1650
    }
    gcaligned = '\xc0'
  }
}
(lldb) p *$9
error: Couldn't apply expression side effects : Couldn't dematerialize a result variable: couldn't read its memory
(lldb) p *(struct igc_header *) client_to_base ($9)
error: Couldn't apply expression side effects : Couldn't dematerialize a result variable: couldn't read its memory
(lldb) memory read 0x000000010f0f1610
error: memory read failed for 0x10f0f1600
(lldb) xpostmortem
(lldb) memory read 0x000000010f0f1610
0x10f0f1610: 17 00 00 00 00 00 00 00 17 00 00 00 00 00 00 00  ................
0x10f0f1620: 00 00 00 00 00 00 00 00 08 b0 0e 0f 01 00 00 00  ................
(lldb) p *(struct Lisp_String *)0x000000010f0f1610
(struct Lisp_String) {
  u = {
    s = {
      size = 23
      size_byte = 23
      intervals = NULL
      data = 0x000000010f0eb008 "byte-compile-form-stack"
    }
    next = 0x0000000000000017
    gcaligned = '\x17'
  }
}
#+end_src