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bug#32405: [PATCH] Turn misc objects into pseudovectors


From: Paul Eggert
Subject: bug#32405: [PATCH] Turn misc objects into pseudovectors
Date: Wed, 8 Aug 2018 19:58:52 -0700

Eliminate the category of miscellaneous objects, and turn all
such objects into pseudovectors.  The immediate motivation
for this change is to free up an enum Lisp_Type tag value, a
scarce resource that can be better used elsewhere.  However,
this change is worthwhile in its own right, as it improves
performance slightly on my platform, 0.3% faster for 'make
compile-always' on Fedora 28, and it simplifies the garbage
collector and interpreter.
* doc/lispref/internals.texi (Garbage Collection):
* etc/NEWS:
Document change to garbage-collect return value.
* src/alloc.c (total_markers, total_free_markers):
(union aligned_Lisp_Misc, MARKER_BLOCK_SIZE)
(struct marker_block, marker_block, marker_block_index)
(misc_free_list, allocate_misc, live_misc_holding)
(live_misc_p, sweep_misc):
* src/lisp.h (lisp_h_MARKERP, lisp_h_MISCP, MARKERP, MISCP)
(Lisp_Misc, enum Lisp_Misc_Type, Lisp_Misc_Free)
(Lisp_Misc_Marker, Lisp_Misc_Overlay, Lisp_Misc_Finalizer)
(Lisp_Misc_Ptr, Lisp_Misc_User_Ptr, Lisp_Misc_Limit)
(XSETMISC, struct Lisp_Misc_Any, XMISCANY, XMISCTYPE)
(struct Lisp_Free, union Lisp_Misc, XMISC):
Remove.  All uses removed.
(cleanup_vector): Clean up objects that were formerly misc
and are now pseudovectors.
(make_misc_ptr, build_overlay, Fmake_marker, build_marker)
(make_user_ptr, Fmake_finalizer):
Build as pseudovectors, not as misc objects.
(mark_finalizer_list, queue_doomed_finalizers)
(compact_undo_list, mark_overlay, mark_object)
(unchain_dead_markers):
Mark as vector-like objects, not as misc objects.
(mark_maybe_object, mark_maybe_pointer, valid_lisp_object_p)
(total_bytes_of_live_objects, survives_gc_p):
* src/fns.c (sxhash):
No need to worry about misc objects.
(garbage_collect_1): Do not generate a 'misc' component.
(syms_of_alloc): No need for 'misc' symbol.
* src/buffer.c (overlays_at, overlays_in, overlay_touches_p)
(overlay_strings, recenter_overlay_lists)
(fix_start_end_in_overlays, fix_overlays_before)
(Foverlay_lists, report_overlay_modification)
(evaporate_overlays):
* src/editfns.c (overlays_around):
* src/data.c (Ftype_of):
* src/fns.c (internal_equal):
* src/lisp.h (mint_ptrp, xmint_pointer, FINALIZERP)
(XFINALIZER, MARKERP, XMARKER, OVERLAYP, XOVERLAY, USER_PTRP)
(XUSER_PTR):
* src/print.c (print_vectorlike, print_object):
* src/undo.c (record_marker_adjustments):
* src/xdisp.c (load_overlay_strings):
Formerly misc objects are now pseudovectors.
* src/lisp.h (PVEC_MARKER, PVEC_OVERLAY, PVEC_FINALIZER)
(PVEC_MISC_PTR, PVEC_USER_PTR):
New constants, replacing their misc versions.  All uses changed.
(struct Lisp_Marker, struct Lisp_Overlay, struct Lisp_Misc_Ptr)
(struct Lisp_User_Ptr, struct Lisp_Finalizer):
Make usable as a pseudovector by using a pseudovector header,
replacing any DIY components, and putting Lisp_Object members
first.  All uses changed.
---
 doc/lispref/internals.texi |  11 +-
 etc/NEWS                   |   4 +
 src/alloc.c                | 349 ++++++++-----------------------------
 src/buffer.c               | 250 ++++++++++++--------------
 src/data.c                 |  24 +--
 src/editfns.c              |  31 ++--
 src/fns.c                  |  44 ++---
 src/lisp.h                 | 195 +++++----------------
 src/print.c                | 147 +++++++---------
 src/undo.c                 |  14 +-
 src/xdisp.c                |  45 +++--
 11 files changed, 360 insertions(+), 754 deletions(-)

diff --git a/doc/lispref/internals.texi b/doc/lispref/internals.texi
index 65752860bf..1dc5de0a69 100644
--- a/doc/lispref/internals.texi
+++ b/doc/lispref/internals.texi
@@ -318,7 +318,6 @@ Garbage Collection
 @example
 ((@code{conses} @var{cons-size} @var{used-conses} @var{free-conses})
  (@code{symbols} @var{symbol-size} @var{used-symbols} @var{free-symbols})
- (@code{miscs} @var{misc-size} @var{used-miscs} @var{free-miscs})
  (@code{strings} @var{string-size} @var{used-strings} @var{free-strings})
  (@code{string-bytes} @var{byte-size} @var{used-bytes})
  (@code{vectors} @var{vector-size} @var{used-vectors})
@@ -334,7 +333,7 @@ Garbage Collection
 @example
 (garbage-collect)
       @result{} ((conses 16 49126 8058) (symbols 48 14607 0)
-                 (miscs 40 34 56) (strings 32 2942 2607)
+                 (strings 32 2942 2607)
                  (string-bytes 1 78607) (vectors 16 7247)
                  (vector-slots 8 341609 29474) (floats 8 71 102)
                  (intervals 56 27 26) (buffers 944 8)
@@ -371,14 +370,6 @@ Garbage Collection
 @code{sizeof (union Lisp_Misc)}, which is a size of the
 largest type enumerated in @code{enum Lisp_Misc_Type}.
 
address@hidden used-miscs
-The number of miscellaneous objects in use.  These include markers
-and overlays, plus certain objects not visible to users.
-
address@hidden free-miscs
-The number of miscellaneous objects for which space has been obtained
-from the operating system, but that are not currently being used.
-
 @item string-size
 Internal size of a string header, i.e., @code{sizeof (struct Lisp_String)}.
 
diff --git a/etc/NEWS b/etc/NEWS
index 21887f5bfd..54dcc7e873 100644
--- a/etc/NEWS
+++ b/etc/NEWS
@@ -811,6 +811,10 @@ is backwards-compatible with versions of Emacs in which 
the old function
 exists.  See the node "Displaying Buffers in Side Windows" in the ELisp
 manual for more details.
 
+** The 'garbage-collect' function no longer returns a 'misc' component
+because garbage collection no longer treats miscellaneous objects
+specially; they are now allocated like any other pseudovector.
+
 
 * Lisp Changes in Emacs 27.1
 
diff --git a/src/alloc.c b/src/alloc.c
index e4b54aba86..dcf11825bc 100644
--- a/src/alloc.c
+++ b/src/alloc.c
@@ -247,8 +247,8 @@ bool gc_in_progress;
 
 /* Number of live and free conses etc.  */
 
-static EMACS_INT total_conses, total_markers, total_symbols, total_buffers;
-static EMACS_INT total_free_conses, total_free_markers, total_free_symbols;
+static EMACS_INT total_conses, total_symbols, total_buffers;
+static EMACS_INT total_free_conses, total_free_symbols;
 static EMACS_INT total_free_floats, total_floats;
 
 /* Points to memory space allocated as "spare", to be freed if we run
@@ -356,6 +356,7 @@ no_sanitize_memcpy (void *dest, void const *src, size_t 
size)
 
 #endif /* MAX_SAVE_STACK > 0 */
 
+static void unchain_finalizer (struct Lisp_Finalizer *);
 static void mark_terminals (void);
 static void gc_sweep (void);
 static Lisp_Object make_pure_vector (ptrdiff_t);
@@ -3197,7 +3198,10 @@ static void
 cleanup_vector (struct Lisp_Vector *vector)
 {
   detect_suspicious_free (vector);
-  if (PSEUDOVECTOR_TYPEP (&vector->header, PVEC_FONT))
+
+  if (PSEUDOVECTOR_TYPEP (&vector->header, PVEC_FINALIZER))
+    unchain_finalizer (PSEUDOVEC_STRUCT (vector, Lisp_Finalizer));
+  else if (PSEUDOVECTOR_TYPEP (&vector->header, PVEC_FONT))
     {
       if ((vector->header.size & PSEUDOVECTOR_SIZE_MASK) == FONT_OBJECT_MAX)
        {
@@ -3220,6 +3224,19 @@ cleanup_vector (struct Lisp_Vector *vector)
     finalize_one_mutex (PSEUDOVEC_STRUCT (vector, Lisp_Mutex));
   else if (PSEUDOVECTOR_TYPEP (&vector->header, PVEC_CONDVAR))
     finalize_one_condvar (PSEUDOVEC_STRUCT (vector, Lisp_CondVar));
+  else if (PSEUDOVECTOR_TYPEP (&vector->header, PVEC_MARKER))
+    {
+      /* sweep_buffer should already have unchained this from its buffer.  */
+      eassert (! PSEUDOVEC_STRUCT (vector, Lisp_Marker)->buffer);
+    }
+#ifdef HAVE_MODULES
+  else if (PSEUDOVECTOR_TYPEP (&vector->header, PVEC_USER_PTR))
+    {
+      struct Lisp_User_Ptr *uptr = PSEUDOVEC_STRUCT (vector, Lisp_User_Ptr);
+      if (uptr->finalizer)
+       uptr->finalizer (uptr->p);
+    }
+#endif
 }
 
 /* Reclaim space used by unmarked vectors.  */
@@ -3650,96 +3667,27 @@ Its value is void, and its function definition and 
property list are nil.  */)
 
 
 
-/***********************************************************************
-                      Marker (Misc) Allocation
- ***********************************************************************/
-
-/* Like union Lisp_Misc, but padded so that its size is a multiple of
-   the required alignment.  */
-
-union aligned_Lisp_Misc
-{
-  union Lisp_Misc m;
-  unsigned char c[(sizeof (union Lisp_Misc) + LISP_ALIGNMENT - 1)
-                 & -LISP_ALIGNMENT];
-};
-
-/* Allocation of markers and other objects that share that structure.
-   Works like allocation of conses.  */
-
-#define MARKER_BLOCK_SIZE \
-  ((1020 - sizeof (struct marker_block *)) / sizeof (union aligned_Lisp_Misc))
-
-struct marker_block
-{
-  /* Place `markers' first, to preserve alignment.  */
-  union aligned_Lisp_Misc markers[MARKER_BLOCK_SIZE];
-  struct marker_block *next;
-};
-
-static struct marker_block *marker_block;
-static int marker_block_index = MARKER_BLOCK_SIZE;
-
-static union Lisp_Misc *misc_free_list;
-
-/* Return a newly allocated Lisp_Misc object of specified TYPE.  */
-
-static Lisp_Object
-allocate_misc (enum Lisp_Misc_Type type)
-{
-  Lisp_Object val;
-
-  MALLOC_BLOCK_INPUT;
-
-  if (misc_free_list)
-    {
-      XSETMISC (val, misc_free_list);
-      misc_free_list = misc_free_list->u_free.chain;
-    }
-  else
-    {
-      if (marker_block_index == MARKER_BLOCK_SIZE)
-       {
-         struct marker_block *new = lisp_malloc (sizeof *new, MEM_TYPE_MISC);
-         new->next = marker_block;
-         marker_block = new;
-         marker_block_index = 0;
-         total_free_markers += MARKER_BLOCK_SIZE;
-       }
-      XSETMISC (val, &marker_block->markers[marker_block_index].m);
-      marker_block_index++;
-    }
-
-  MALLOC_UNBLOCK_INPUT;
-
-  --total_free_markers;
-  consing_since_gc += sizeof (union Lisp_Misc);
-  misc_objects_consed++;
-  XMISCANY (val)->type = type;
-  XMISCANY (val)->gcmarkbit = 0;
-  return val;
-}
-
 Lisp_Object
 make_misc_ptr (void *a)
 {
-  Lisp_Object val = allocate_misc (Lisp_Misc_Ptr);
-  XUNTAG (val, Lisp_Misc, struct Lisp_Misc_Ptr)->pointer = a;
-  return val;
+  struct Lisp_Misc_Ptr *p = ALLOCATE_PSEUDOVECTOR (struct Lisp_Misc_Ptr, 
pointer,
+                                                  PVEC_MISC_PTR);
+  p->pointer = a;
+  return make_lisp_ptr (p, Lisp_Vectorlike);
 }
 
-/* Return a Lisp_Misc_Overlay object with specified START, END and PLIST.  */
+/* Return a new overlay with specified START, END and PLIST.  */
 
 Lisp_Object
 build_overlay (Lisp_Object start, Lisp_Object end, Lisp_Object plist)
 {
-  register Lisp_Object overlay;
-
-  overlay = allocate_misc (Lisp_Misc_Overlay);
+  struct Lisp_Overlay *p = ALLOCATE_PSEUDOVECTOR (struct Lisp_Overlay, next,
+                                                 PVEC_OVERLAY);
+  Lisp_Object overlay = make_lisp_ptr (p, Lisp_Vectorlike);
   OVERLAY_START (overlay) = start;
   OVERLAY_END (overlay) = end;
   set_overlay_plist (overlay, plist);
-  XOVERLAY (overlay)->next = NULL;
+  p->next = NULL;
   return overlay;
 }
 
@@ -3747,18 +3695,15 @@ DEFUN ("make-marker", Fmake_marker, Smake_marker, 0, 0, 
0,
        doc: /* Return a newly allocated marker which does not point at any 
place.  */)
   (void)
 {
-  register Lisp_Object val;
-  register struct Lisp_Marker *p;
-
-  val = allocate_misc (Lisp_Misc_Marker);
-  p = XMARKER (val);
+  struct Lisp_Marker *p = ALLOCATE_PSEUDOVECTOR (struct Lisp_Marker, buffer,
+                                                PVEC_MARKER);
   p->buffer = 0;
   p->bytepos = 0;
   p->charpos = 0;
   p->next = NULL;
   p->insertion_type = 0;
   p->need_adjustment = 0;
-  return val;
+  return make_lisp_ptr (p, Lisp_Vectorlike);
 }
 
 /* Return a newly allocated marker which points into BUF
@@ -3767,17 +3712,14 @@ DEFUN ("make-marker", Fmake_marker, Smake_marker, 0, 0, 
0,
 Lisp_Object
 build_marker (struct buffer *buf, ptrdiff_t charpos, ptrdiff_t bytepos)
 {
-  Lisp_Object obj;
-  struct Lisp_Marker *m;
-
   /* No dead buffers here.  */
   eassert (BUFFER_LIVE_P (buf));
 
   /* Every character is at least one byte.  */
   eassert (charpos <= bytepos);
 
-  obj = allocate_misc (Lisp_Misc_Marker);
-  m = XMARKER (obj);
+  struct Lisp_Marker *m = ALLOCATE_PSEUDOVECTOR (struct Lisp_Marker, buffer,
+                                                PVEC_MARKER);
   m->buffer = buf;
   m->charpos = charpos;
   m->bytepos = bytepos;
@@ -3785,7 +3727,7 @@ build_marker (struct buffer *buf, ptrdiff_t charpos, 
ptrdiff_t bytepos)
   m->need_adjustment = 0;
   m->next = BUF_MARKERS (buf);
   BUF_MARKERS (buf) = m;
-  return obj;
+  return make_lisp_ptr (m, Lisp_Vectorlike);
 }
 
 
@@ -3831,14 +3773,11 @@ make_event_array (ptrdiff_t nargs, Lisp_Object *args)
 Lisp_Object
 make_user_ptr (void (*finalizer) (void *), void *p)
 {
-  Lisp_Object obj;
-  struct Lisp_User_Ptr *uptr;
-
-  obj = allocate_misc (Lisp_Misc_User_Ptr);
-  uptr = XUSER_PTR (obj);
+  struct Lisp_User_Ptr *uptr = ALLOCATE_PSEUDOVECTOR (struct Lisp_User_Ptr,
+                                                     finalizer, PVEC_USER_PTR);
   uptr->finalizer = finalizer;
   uptr->p = p;
-  return obj;
+  return make_lisp_ptr (uptr, Lisp_Vectorlike);
 }
 #endif
 
@@ -3881,7 +3820,7 @@ mark_finalizer_list (struct Lisp_Finalizer *head)
        finalizer != head;
        finalizer = finalizer->next)
     {
-      finalizer->base.gcmarkbit = true;
+      VECTOR_MARK (finalizer);
       mark_object (finalizer->function);
     }
 }
@@ -3898,7 +3837,7 @@ queue_doomed_finalizers (struct Lisp_Finalizer *dest,
   while (finalizer != src)
     {
       struct Lisp_Finalizer *next = finalizer->next;
-      if (!finalizer->base.gcmarkbit && !NILP (finalizer->function))
+      if (!VECTOR_MARKED_P (finalizer) && !NILP (finalizer->function))
         {
           unchain_finalizer (finalizer);
           finalizer_insert (dest, finalizer);
@@ -3934,7 +3873,6 @@ run_finalizers (struct Lisp_Finalizer *finalizers)
   while (finalizers->next != finalizers)
     {
       finalizer = finalizers->next;
-      eassert (finalizer->base.type == Lisp_Misc_Finalizer);
       unchain_finalizer (finalizer);
       function = finalizer->function;
       if (!NILP (function))
@@ -3954,12 +3892,12 @@ count as reachable for the purpose of deciding whether 
to run
 FUNCTION.  FUNCTION will be run once per finalizer object.  */)
   (Lisp_Object function)
 {
-  Lisp_Object val = allocate_misc (Lisp_Misc_Finalizer);
-  struct Lisp_Finalizer *finalizer = XFINALIZER (val);
+  struct Lisp_Finalizer *finalizer
+    = ALLOCATE_PSEUDOVECTOR (struct Lisp_Finalizer, prev, PVEC_FINALIZER);
   finalizer->function = function;
   finalizer->prev = finalizer->next = NULL;
   finalizer_insert (&finalizers, finalizer);
-  return val;
+  return make_lisp_ptr (finalizer, Lisp_Vectorlike);
 }
 
 
@@ -4580,41 +4518,6 @@ live_float_p (struct mem_node *m, void *p)
     return 0;
 }
 
-
-/* If P is a pointer to a live Lisp Misc on the heap, return the object.
-   Otherwise, return nil.  M is a pointer to the mem_block for P.  */
-
-static Lisp_Object
-live_misc_holding (struct mem_node *m, void *p)
-{
-  if (m->type == MEM_TYPE_MISC)
-    {
-      struct marker_block *b = m->start;
-      char *cp = p;
-      ptrdiff_t offset = cp - (char *) &b->markers[0];
-
-      /* P must point into a Lisp_Misc, not be
-        one of the unused cells in the current misc block,
-        and not be on the free-list.  */
-      if (0 <= offset && offset < MARKER_BLOCK_SIZE * sizeof b->markers[0]
-         && (b != marker_block
-             || offset / sizeof b->markers[0] < marker_block_index))
-       {
-         cp = ptr_bounds_copy (cp, b);
-         union Lisp_Misc *s = p = cp -= offset % sizeof b->markers[0];
-         if (s->u_any.type != Lisp_Misc_Free)
-           return make_lisp_ptr (s, Lisp_Misc);
-       }
-    }
-  return Qnil;
-}
-
-static bool
-live_misc_p (struct mem_node *m, void *p)
-{
-  return !NILP (live_misc_holding (m, p));
-}
-
 /* If P is a pointer to a live vector-like object, return the object.
    Otherwise, return nil.
    M is a pointer to the mem_block for P.  */
@@ -4733,10 +4636,6 @@ mark_maybe_object (Lisp_Object obj)
                    || EQ (obj, live_buffer_holding (m, po)));
          break;
 
-       case Lisp_Misc:
-         mark_p = EQ (obj, live_misc_holding (m, po));
-         break;
-
        default:
          break;
        }
@@ -4818,10 +4717,6 @@ mark_maybe_pointer (void *p)
          obj = live_string_holding (m, p);
          break;
 
-       case MEM_TYPE_MISC:
-         obj = live_misc_holding (m, p);
-         break;
-
        case MEM_TYPE_SYMBOL:
          obj = live_symbol_holding (m, p);
          break;
@@ -5222,9 +5117,6 @@ valid_lisp_object_p (Lisp_Object obj)
     case MEM_TYPE_STRING:
       return live_string_p (m, p);
 
-    case MEM_TYPE_MISC:
-      return live_misc_p (m, p);
-
     case MEM_TYPE_SYMBOL:
       return live_symbol_p (m, p);
 
@@ -5644,7 +5536,6 @@ total_bytes_of_live_objects (void)
   size_t tot = 0;
   tot += total_conses  * sizeof (struct Lisp_Cons);
   tot += total_symbols * sizeof (struct Lisp_Symbol);
-  tot += total_markers * sizeof (union Lisp_Misc);
   tot += total_string_bytes;
   tot += total_vector_slots * word_size;
   tot += total_floats  * sizeof (struct Lisp_Float);
@@ -5765,7 +5656,7 @@ compact_undo_list (Lisp_Object list)
     {
       if (CONSP (XCAR (tail))
          && MARKERP (XCAR (XCAR (tail)))
-         && !XMARKER (XCAR (XCAR (tail)))->gcmarkbit)
+         && !VECTOR_MARKED_P (XMARKER (XCAR (XCAR (tail)))))
        *prev = XCDR (tail);
       else
        prev = xcdr_addr (tail);
@@ -5992,9 +5883,6 @@ garbage_collect_1 (void *end)
     list4 (Qsymbols, make_number (sizeof (struct Lisp_Symbol)),
           bounded_number (total_symbols),
           bounded_number (total_free_symbols)),
-    list4 (Qmiscs, make_number (sizeof (union Lisp_Misc)),
-          bounded_number (total_markers),
-          bounded_number (total_free_markers)),
     list4 (Qstrings, make_number (sizeof (struct Lisp_String)),
           bounded_number (total_strings),
           bounded_number (total_free_strings)),
@@ -6181,12 +6069,12 @@ mark_compiled (struct Lisp_Vector *ptr)
 static void
 mark_overlay (struct Lisp_Overlay *ptr)
 {
-  for (; ptr && !ptr->gcmarkbit; ptr = ptr->next)
+  for (; ptr && !VECTOR_MARKED_P (ptr); ptr = ptr->next)
     {
-      ptr->gcmarkbit = 1;
+      VECTOR_MARK (ptr);
       /* These two are always markers and can be marked fast.  */
-      XMARKER (ptr->start)->gcmarkbit = 1;
-      XMARKER (ptr->end)->gcmarkbit = 1;
+      VECTOR_MARK (XMARKER (ptr->start));
+      VECTOR_MARK (XMARKER (ptr->end));
       mark_object (ptr->plist);
     }
 }
@@ -6487,11 +6375,28 @@ mark_object (Lisp_Object arg)
            mark_char_table (ptr, (enum pvec_type) pvectype);
            break;
 
+         case PVEC_MARKER:
+           /* DO NOT mark thru the marker's chain.
+              The buffer's markers chain does not preserve markers from gc;
+              instead, markers are removed from the chain when freed by gc.  */
          case PVEC_BOOL_VECTOR:
-           /* No Lisp_Objects to mark in a bool vector.  */
+         case PVEC_MISC_PTR:
+#ifdef HAVE_MODULES
+         case PVEC_USER_PTR:
+#endif
+           /* No Lisp_Objects to mark in these.  */
            VECTOR_MARK (ptr);
            break;
 
+         case PVEC_OVERLAY:
+           mark_overlay (XOVERLAY (obj));
+           break;
+
+         case PVEC_FINALIZER:
+           VECTOR_MARK (ptr);
+           mark_object (XFINALIZER (obj)->function);
+           break;
+
          case PVEC_SUBR:
            break;
 
@@ -6547,48 +6452,9 @@ mark_object (Lisp_Object arg)
       }
       break;
 
-    case Lisp_Misc:
-      CHECK_ALLOCATED_AND_LIVE (live_misc_p);
-
-      if (XMISCANY (obj)->gcmarkbit)
-       break;
-
-      switch (XMISCTYPE (obj))
-       {
-       case Lisp_Misc_Marker:
-         /* DO NOT mark thru the marker's chain.
-            The buffer's markers chain does not preserve markers from gc;
-            instead, markers are removed from the chain when freed by gc.  */
-         XMISCANY (obj)->gcmarkbit = 1;
-         break;
-
-       case Lisp_Misc_Ptr:
-         XMISCANY (obj)->gcmarkbit = true;
-         break;
-
-       case Lisp_Misc_Overlay:
-         mark_overlay (XOVERLAY (obj));
-          break;
-
-        case Lisp_Misc_Finalizer:
-          XMISCANY (obj)->gcmarkbit = true;
-          mark_object (XFINALIZER (obj)->function);
-          break;
-
-#ifdef HAVE_MODULES
-       case Lisp_Misc_User_Ptr:
-         XMISCANY (obj)->gcmarkbit = true;
-         break;
-#endif
-
-       default:
-         emacs_abort ();
-       }
-      break;
-
     case Lisp_Cons:
       {
-       register struct Lisp_Cons *ptr = XCONS (obj);
+       struct Lisp_Cons *ptr = XCONS (obj);
        if (CONS_MARKED_P (ptr))
          break;
        CHECK_ALLOCATED_AND_LIVE (live_cons_p);
@@ -6665,10 +6531,6 @@ survives_gc_p (Lisp_Object obj)
       survives_p = XSYMBOL (obj)->u.s.gcmarkbit;
       break;
 
-    case Lisp_Misc:
-      survives_p = XMISCANY (obj)->gcmarkbit;
-      break;
-
     case Lisp_String:
       survives_p = STRING_MARKED_P (XSTRING (obj));
       break;
@@ -6945,79 +6807,6 @@ sweep_symbols (void)
   total_free_symbols = num_free;
 }
 
-NO_INLINE /* For better stack traces.  */
-static void
-sweep_misc (void)
-{
-  register struct marker_block *mblk;
-  struct marker_block **mprev = &marker_block;
-  register int lim = marker_block_index;
-  EMACS_INT num_free = 0, num_used = 0;
-
-  /* Put all unmarked misc's on free list.  For a marker, first
-     unchain it from the buffer it points into.  */
-
-  misc_free_list = 0;
-
-  for (mblk = marker_block; mblk; mblk = *mprev)
-    {
-      register int i;
-      int this_free = 0;
-
-      for (i = 0; i < lim; i++)
-        {
-          if (!mblk->markers[i].m.u_any.gcmarkbit)
-            {
-              if (mblk->markers[i].m.u_any.type == Lisp_Misc_Marker)
-                /* Make sure markers have been unchained from their buffer
-                   in sweep_buffer before we collect them.  */
-                eassert (!mblk->markers[i].m.u_marker.buffer);
-              else if (mblk->markers[i].m.u_any.type == Lisp_Misc_Finalizer)
-                unchain_finalizer (&mblk->markers[i].m.u_finalizer);
-#ifdef HAVE_MODULES
-             else if (mblk->markers[i].m.u_any.type == Lisp_Misc_User_Ptr)
-               {
-                 struct Lisp_User_Ptr *uptr = &mblk->markers[i].m.u_user_ptr;
-                 if (uptr->finalizer)
-                   uptr->finalizer (uptr->p);
-               }
-#endif
-              /* Set the type of the freed object to Lisp_Misc_Free.
-                 We could leave the type alone, since nobody checks it,
-                 but this might catch bugs faster.  */
-              mblk->markers[i].m.u_marker.type = Lisp_Misc_Free;
-              mblk->markers[i].m.u_free.chain = misc_free_list;
-              misc_free_list = &mblk->markers[i].m;
-              this_free++;
-            }
-          else
-            {
-              num_used++;
-              mblk->markers[i].m.u_any.gcmarkbit = 0;
-            }
-        }
-      lim = MARKER_BLOCK_SIZE;
-      /* If this block contains only free markers and we have already
-         seen more than two blocks worth of free markers then deallocate
-         this block.  */
-      if (this_free == MARKER_BLOCK_SIZE && num_free > MARKER_BLOCK_SIZE)
-        {
-          *mprev = mblk->next;
-          /* Unhook from the free list.  */
-          misc_free_list = mblk->markers[0].m.u_free.chain;
-          lisp_free (mblk);
-        }
-      else
-        {
-          num_free += this_free;
-          mprev = &mblk->next;
-        }
-    }
-
-  total_markers = num_used;
-  total_free_markers = num_free;
-}
-
 /* Remove BUFFER's markers that are due to be swept.  This is needed since
    we treat BUF_MARKERS and markers's `next' field as weak pointers.  */
 static void
@@ -7026,7 +6815,7 @@ unchain_dead_markers (struct buffer *buffer)
   struct Lisp_Marker *this, **prev = &BUF_MARKERS (buffer);
 
   while ((this = *prev))
-    if (this->gcmarkbit)
+    if (VECTOR_MARKED_P (this))
       prev = &this->next;
     else
       {
@@ -7074,7 +6863,6 @@ gc_sweep (void)
   sweep_intervals ();
   sweep_symbols ();
   sweep_buffers ();
-  sweep_misc ();
   sweep_vectors ();
   check_string_bytes (!noninteractive);
 }
@@ -7449,7 +7237,6 @@ do hash-consing of the objects allocated to pure space.  
*/);
 
   DEFSYM (Qconses, "conses");
   DEFSYM (Qsymbols, "symbols");
-  DEFSYM (Qmiscs, "miscs");
   DEFSYM (Qstrings, "strings");
   DEFSYM (Qvectors, "vectors");
   DEFSYM (Qfloats, "floats");
diff --git a/src/buffer.c b/src/buffer.c
index 244c1851fa..bfbb5eaba6 100644
--- a/src/buffer.c
+++ b/src/buffer.c
@@ -2789,8 +2789,6 @@ overlays_at (EMACS_INT pos, bool extend, Lisp_Object 
**vec_ptr,
             ptrdiff_t *len_ptr,
             ptrdiff_t *next_ptr, ptrdiff_t *prev_ptr, bool change_req)
 {
-  Lisp_Object overlay, start, end;
-  struct Lisp_Overlay *tail;
   ptrdiff_t idx = 0;
   ptrdiff_t len = *len_ptr;
   Lisp_Object *vec = *vec_ptr;
@@ -2798,22 +2796,20 @@ overlays_at (EMACS_INT pos, bool extend, Lisp_Object 
**vec_ptr,
   ptrdiff_t prev = BEGV;
   bool inhibit_storing = 0;
 
-  for (tail = current_buffer->overlays_before; tail; tail = tail->next)
+  for (struct Lisp_Overlay *tail = current_buffer->overlays_before;
+       tail; tail = tail->next)
     {
-      ptrdiff_t startpos, endpos;
-
-      XSETMISC (overlay, tail);
-
-      start = OVERLAY_START (overlay);
-      end = OVERLAY_END (overlay);
-      endpos = OVERLAY_POSITION (end);
+      Lisp_Object overlay = make_lisp_ptr (tail, Lisp_Vectorlike);
+      Lisp_Object start = OVERLAY_START (overlay);
+      Lisp_Object end = OVERLAY_END (overlay);
+      ptrdiff_t endpos = OVERLAY_POSITION (end);
       if (endpos < pos)
        {
          if (prev < endpos)
            prev = endpos;
          break;
        }
-      startpos = OVERLAY_POSITION (start);
+      ptrdiff_t startpos = OVERLAY_POSITION (start);
       /* This one ends at or after POS
         so its start counts for PREV_PTR if it's before POS.  */
       if (prev < startpos && startpos < pos)
@@ -2846,22 +2842,20 @@ overlays_at (EMACS_INT pos, bool extend, Lisp_Object 
**vec_ptr,
        next = startpos;
     }
 
-  for (tail = current_buffer->overlays_after; tail; tail = tail->next)
+  for (struct Lisp_Overlay *tail = current_buffer->overlays_after;
+       tail; tail = tail->next)
     {
-      ptrdiff_t startpos, endpos;
-
-      XSETMISC (overlay, tail);
-
-      start = OVERLAY_START (overlay);
-      end = OVERLAY_END (overlay);
-      startpos = OVERLAY_POSITION (start);
+      Lisp_Object overlay = make_lisp_ptr (tail, Lisp_Vectorlike);
+      Lisp_Object start = OVERLAY_START (overlay);
+      Lisp_Object end = OVERLAY_END (overlay);
+      ptrdiff_t startpos = OVERLAY_POSITION (start);
       if (pos < startpos)
        {
          if (startpos < next)
            next = startpos;
          break;
        }
-      endpos = OVERLAY_POSITION (end);
+      ptrdiff_t endpos = OVERLAY_POSITION (end);
       if (pos < endpos)
        {
          if (idx == len)
@@ -2923,8 +2917,6 @@ overlays_in (EMACS_INT beg, EMACS_INT end, bool extend,
             Lisp_Object **vec_ptr, ptrdiff_t *len_ptr,
             ptrdiff_t *next_ptr, ptrdiff_t *prev_ptr)
 {
-  Lisp_Object overlay, ostart, oend;
-  struct Lisp_Overlay *tail;
   ptrdiff_t idx = 0;
   ptrdiff_t len = *len_ptr;
   Lisp_Object *vec = *vec_ptr;
@@ -2933,22 +2925,20 @@ overlays_in (EMACS_INT beg, EMACS_INT end, bool extend,
   bool inhibit_storing = 0;
   bool end_is_Z = end == Z;
 
-  for (tail = current_buffer->overlays_before; tail; tail = tail->next)
+  for (struct Lisp_Overlay *tail = current_buffer->overlays_before;
+       tail; tail = tail->next)
     {
-      ptrdiff_t startpos, endpos;
-
-      XSETMISC (overlay, tail);
-
-      ostart = OVERLAY_START (overlay);
-      oend = OVERLAY_END (overlay);
-      endpos = OVERLAY_POSITION (oend);
+      Lisp_Object overlay = make_lisp_ptr (tail, Lisp_Vectorlike);
+      Lisp_Object ostart = OVERLAY_START (overlay);
+      Lisp_Object oend = OVERLAY_END (overlay);
+      ptrdiff_t endpos = OVERLAY_POSITION (oend);
       if (endpos < beg)
        {
          if (prev < endpos)
            prev = endpos;
          break;
        }
-      startpos = OVERLAY_POSITION (ostart);
+      ptrdiff_t startpos = OVERLAY_POSITION (ostart);
       /* Count an interval if it overlaps the range, is empty at the
         start of the range, or is empty at END provided END denotes the
         end of the buffer.  */
@@ -2980,22 +2970,20 @@ overlays_in (EMACS_INT beg, EMACS_INT end, bool extend,
        next = startpos;
     }
 
-  for (tail = current_buffer->overlays_after; tail; tail = tail->next)
+  for (struct Lisp_Overlay *tail = current_buffer->overlays_after;
+       tail; tail = tail->next)
     {
-      ptrdiff_t startpos, endpos;
-
-      XSETMISC (overlay, tail);
-
-      ostart = OVERLAY_START (overlay);
-      oend = OVERLAY_END (overlay);
-      startpos = OVERLAY_POSITION (ostart);
+      Lisp_Object overlay = make_lisp_ptr (tail, Lisp_Vectorlike);
+      Lisp_Object ostart = OVERLAY_START (overlay);
+      Lisp_Object oend = OVERLAY_END (overlay);
+      ptrdiff_t startpos = OVERLAY_POSITION (ostart);
       if (end < startpos)
        {
          if (startpos < next)
            next = startpos;
          break;
        }
-      endpos = OVERLAY_POSITION (oend);
+      ptrdiff_t endpos = OVERLAY_POSITION (oend);
       /* Count an interval if it overlaps the range, is empty at the
         start of the range, or is empty at END provided END denotes the
         end of the buffer.  */
@@ -3097,31 +3085,26 @@ disable_line_numbers_overlay_at_eob (void)
 bool
 overlay_touches_p (ptrdiff_t pos)
 {
-  Lisp_Object overlay;
-  struct Lisp_Overlay *tail;
-
-  for (tail = current_buffer->overlays_before; tail; tail = tail->next)
+  for (struct Lisp_Overlay *tail = current_buffer->overlays_before;
+       tail; tail = tail->next)
     {
-      ptrdiff_t endpos;
-
-      XSETMISC (overlay ,tail);
+      Lisp_Object overlay = make_lisp_ptr (tail, Lisp_Vectorlike);
       eassert (OVERLAYP (overlay));
 
-      endpos = OVERLAY_POSITION (OVERLAY_END (overlay));
+      ptrdiff_t endpos = OVERLAY_POSITION (OVERLAY_END (overlay));
       if (endpos < pos)
        break;
       if (endpos == pos || OVERLAY_POSITION (OVERLAY_START (overlay)) == pos)
        return 1;
     }
 
-  for (tail = current_buffer->overlays_after; tail; tail = tail->next)
+  for (struct Lisp_Overlay *tail = current_buffer->overlays_after;
+       tail; tail = tail->next)
     {
-      ptrdiff_t startpos;
-
-      XSETMISC (overlay, tail);
+      Lisp_Object overlay = make_lisp_ptr (tail, Lisp_Vectorlike);
       eassert (OVERLAYP (overlay));
 
-      startpos = OVERLAY_POSITION (OVERLAY_START (overlay));
+      ptrdiff_t startpos = OVERLAY_POSITION (OVERLAY_START (overlay));
       if (pos < startpos)
        break;
       if (startpos == pos || OVERLAY_POSITION (OVERLAY_END (overlay)) == pos)
@@ -3337,27 +3320,26 @@ record_overlay_string (struct sortstrlist *ssl, 
Lisp_Object str,
 ptrdiff_t
 overlay_strings (ptrdiff_t pos, struct window *w, unsigned char **pstr)
 {
-  Lisp_Object overlay, window, str;
-  struct Lisp_Overlay *ov;
-  ptrdiff_t startpos, endpos;
   bool multibyte = ! NILP (BVAR (current_buffer, enable_multibyte_characters));
 
   overlay_heads.used = overlay_heads.bytes = 0;
   overlay_tails.used = overlay_tails.bytes = 0;
-  for (ov = current_buffer->overlays_before; ov; ov = ov->next)
+  for (struct Lisp_Overlay *ov = current_buffer->overlays_before;
+       ov; ov = ov->next)
     {
-      XSETMISC (overlay, ov);
+      Lisp_Object overlay = make_lisp_ptr (ov, Lisp_Vectorlike);
       eassert (OVERLAYP (overlay));
 
-      startpos = OVERLAY_POSITION (OVERLAY_START (overlay));
-      endpos = OVERLAY_POSITION (OVERLAY_END (overlay));
+      ptrdiff_t startpos = OVERLAY_POSITION (OVERLAY_START (overlay));
+      ptrdiff_t endpos = OVERLAY_POSITION (OVERLAY_END (overlay));
       if (endpos < pos)
        break;
       if (endpos != pos && startpos != pos)
        continue;
-      window = Foverlay_get (overlay, Qwindow);
+      Lisp_Object window = Foverlay_get (overlay, Qwindow);
       if (WINDOWP (window) && XWINDOW (window) != w)
        continue;
+      Lisp_Object str;
       if (startpos == pos
          && (str = Foverlay_get (overlay, Qbefore_string), STRINGP (str)))
        record_overlay_string (&overlay_heads, str,
@@ -3372,20 +3354,22 @@ overlay_strings (ptrdiff_t pos, struct window *w, 
unsigned char **pstr)
                               Foverlay_get (overlay, Qpriority),
                               endpos - startpos);
     }
-  for (ov = current_buffer->overlays_after; ov; ov = ov->next)
+  for (struct Lisp_Overlay *ov = current_buffer->overlays_after;
+       ov; ov = ov->next)
     {
-      XSETMISC (overlay, ov);
+      Lisp_Object overlay = make_lisp_ptr (ov, Lisp_Vectorlike);
       eassert (OVERLAYP (overlay));
 
-      startpos = OVERLAY_POSITION (OVERLAY_START (overlay));
-      endpos = OVERLAY_POSITION (OVERLAY_END (overlay));
+      ptrdiff_t startpos = OVERLAY_POSITION (OVERLAY_START (overlay));
+      ptrdiff_t endpos = OVERLAY_POSITION (OVERLAY_END (overlay));
       if (startpos > pos)
        break;
       if (endpos != pos && startpos != pos)
        continue;
-      window = Foverlay_get (overlay, Qwindow);
+      Lisp_Object window = Foverlay_get (overlay, Qwindow);
       if (WINDOWP (window) && XWINDOW (window) != w)
        continue;
+      Lisp_Object str;
       if (startpos == pos
          && (str = Foverlay_get (overlay, Qbefore_string), STRINGP (str)))
        record_overlay_string (&overlay_heads, str,
@@ -3460,8 +3444,7 @@ overlay_strings (ptrdiff_t pos, struct window *w, 
unsigned char **pstr)
 void
 recenter_overlay_lists (struct buffer *buf, ptrdiff_t pos)
 {
-  Lisp_Object overlay, beg, end;
-  struct Lisp_Overlay *prev, *tail, *next;
+  struct Lisp_Overlay *prev, *next;
 
   /* See if anything in overlays_before should move to overlays_after.  */
 
@@ -3469,14 +3452,15 @@ recenter_overlay_lists (struct buffer *buf, ptrdiff_t 
pos)
      But we use it for symmetry and in case that should cease to be true
      with some future change.  */
   prev = NULL;
-  for (tail = buf->overlays_before; tail; prev = tail, tail = next)
+  for (struct Lisp_Overlay *tail = buf->overlays_before;
+       tail; prev = tail, tail = next)
     {
       next = tail->next;
-      XSETMISC (overlay, tail);
+      Lisp_Object overlay = make_lisp_ptr (tail, Lisp_Vectorlike);
       eassert (OVERLAYP (overlay));
 
-      beg = OVERLAY_START (overlay);
-      end = OVERLAY_END (overlay);
+      Lisp_Object beg = OVERLAY_START (overlay);
+      Lisp_Object end = OVERLAY_END (overlay);
 
       if (OVERLAY_POSITION (end) > pos)
        {
@@ -3495,12 +3479,10 @@ recenter_overlay_lists (struct buffer *buf, ptrdiff_t 
pos)
          for (other = buf->overlays_after; other;
               other_prev = other, other = other->next)
            {
-             Lisp_Object otherbeg, otheroverlay;
-
-             XSETMISC (otheroverlay, other);
+             Lisp_Object otheroverlay = make_lisp_ptr (other, Lisp_Vectorlike);
              eassert (OVERLAYP (otheroverlay));
 
-             otherbeg = OVERLAY_START (otheroverlay);
+             Lisp_Object otherbeg = OVERLAY_START (otheroverlay);
              if (OVERLAY_POSITION (otherbeg) >= where)
                break;
            }
@@ -3522,14 +3504,15 @@ recenter_overlay_lists (struct buffer *buf, ptrdiff_t 
pos)
 
   /* See if anything in overlays_after should be in overlays_before.  */
   prev = NULL;
-  for (tail = buf->overlays_after; tail; prev = tail, tail = next)
+  for (struct Lisp_Overlay *tail = buf->overlays_after;
+       tail; prev = tail, tail = next)
     {
       next = tail->next;
-      XSETMISC (overlay, tail);
+      Lisp_Object overlay = make_lisp_ptr (tail, Lisp_Vectorlike);
       eassert (OVERLAYP (overlay));
 
-      beg = OVERLAY_START (overlay);
-      end = OVERLAY_END (overlay);
+      Lisp_Object beg = OVERLAY_START (overlay);
+      Lisp_Object end = OVERLAY_END (overlay);
 
       /* Stop looking, when we know that nothing further
         can possibly end before POS.  */
@@ -3553,12 +3536,10 @@ recenter_overlay_lists (struct buffer *buf, ptrdiff_t 
pos)
          for (other = buf->overlays_before; other;
               other_prev = other, other = other->next)
            {
-             Lisp_Object otherend, otheroverlay;
-
-             XSETMISC (otheroverlay, other);
+             Lisp_Object otheroverlay = make_lisp_ptr (other, Lisp_Vectorlike);
              eassert (OVERLAYP (otheroverlay));
 
-             otherend = OVERLAY_END (otheroverlay);
+             Lisp_Object otherend = OVERLAY_END (otheroverlay);
              if (OVERLAY_POSITION (otherend) <= where)
                break;
            }
@@ -3613,7 +3594,6 @@ adjust_overlays_for_delete (ptrdiff_t pos, ptrdiff_t 
length)
 void
 fix_start_end_in_overlays (register ptrdiff_t start, register ptrdiff_t end)
 {
-  Lisp_Object overlay;
   struct Lisp_Overlay *before_list UNINIT;
   struct Lisp_Overlay *after_list UNINIT;
   /* These are either nil, indicating that before_list or after_list
@@ -3623,8 +3603,7 @@ fix_start_end_in_overlays (register ptrdiff_t start, 
register ptrdiff_t end)
   /* 'Parent', likewise, indicates a cons cell or
      current_buffer->overlays_before or overlays_after, depending
      which loop we're in.  */
-  struct Lisp_Overlay *tail, *parent;
-  ptrdiff_t startpos, endpos;
+  struct Lisp_Overlay *parent;
 
   /* This algorithm shifts links around instead of consing and GCing.
      The loop invariant is that before_list (resp. after_list) is a
@@ -3633,12 +3612,14 @@ fix_start_end_in_overlays (register ptrdiff_t start, 
register ptrdiff_t end)
      (after_list) if it is, is still uninitialized.  So it's not a bug
      that before_list isn't initialized, although it may look
      strange.  */
-  for (parent = NULL, tail = current_buffer->overlays_before; tail;)
+  parent = NULL;
+  for (struct Lisp_Overlay *tail = current_buffer->overlays_before;
+       tail; tail = tail->next)
     {
-      XSETMISC (overlay, tail);
+      Lisp_Object overlay = make_lisp_ptr (tail, Lisp_Vectorlike);
 
-      endpos = OVERLAY_POSITION (OVERLAY_END (overlay));
-      startpos = OVERLAY_POSITION (OVERLAY_START (overlay));
+      ptrdiff_t endpos = OVERLAY_POSITION (OVERLAY_END (overlay));
+      ptrdiff_t startpos = OVERLAY_POSITION (OVERLAY_START (overlay));
 
       /* If the overlay is backwards, make it empty.  */
       if (endpos < startpos)
@@ -3676,17 +3657,18 @@ fix_start_end_in_overlays (register ptrdiff_t start, 
register ptrdiff_t end)
            set_buffer_overlays_before (current_buffer, tail->next);
          else
            parent->next = tail->next;
-         tail = tail->next;
        }
       else
-       parent = tail, tail = parent->next;
+       parent = tail;
     }
-  for (parent = NULL, tail = current_buffer->overlays_after; tail;)
+  parent = NULL;
+  for (struct Lisp_Overlay *tail = current_buffer->overlays_after;
+       tail; tail = tail->next)
     {
-      XSETMISC (overlay, tail);
+      Lisp_Object overlay = make_lisp_ptr (tail, Lisp_Vectorlike);
 
-      startpos = OVERLAY_POSITION (OVERLAY_START (overlay));
-      endpos = OVERLAY_POSITION (OVERLAY_END (overlay));
+      ptrdiff_t startpos = OVERLAY_POSITION (OVERLAY_START (overlay));
+      ptrdiff_t endpos = OVERLAY_POSITION (OVERLAY_END (overlay));
 
       /* If the overlay is backwards, make it empty.  */
       if (endpos < startpos)
@@ -3722,10 +3704,9 @@ fix_start_end_in_overlays (register ptrdiff_t start, 
register ptrdiff_t end)
            set_buffer_overlays_after (current_buffer, tail->next);
          else
            parent->next = tail->next;
-         tail = tail->next;
        }
       else
-       parent = tail, tail = parent->next;
+       parent = tail;
     }
 
   /* Splice the constructed (wrong) lists into the buffer's lists,
@@ -3776,7 +3757,7 @@ fix_overlays_before (struct buffer *bp, ptrdiff_t prev, 
ptrdiff_t pos)
      overlay whose ending marker is after-insertion-marker if disorder
      exists).  */
   while (tail
-        && (XSETMISC (tem, tail),
+        && (tem = make_lisp_ptr (tail, Lisp_Vectorlike),
             (end = OVERLAY_POSITION (OVERLAY_END (tem))) >= pos))
     {
       parent = tail;
@@ -3801,7 +3782,7 @@ fix_overlays_before (struct buffer *bp, ptrdiff_t prev, 
ptrdiff_t pos)
      overlays are in correct order.  */
   while (tail)
     {
-      XSETMISC (tem, tail);
+      tem = make_lisp_ptr (tail, Lisp_Vectorlike);
       end = OVERLAY_POSITION (OVERLAY_END (tem));
 
       if (end == pos)
@@ -4308,19 +4289,14 @@ The lists you get are copies, so that changing them has 
no effect.
 However, the overlays you get are the real objects that the buffer uses.  */)
   (void)
 {
-  struct Lisp_Overlay *ol;
-  Lisp_Object before = Qnil, after = Qnil, tmp;
+  Lisp_Object before = Qnil, after = Qnil;
 
-  for (ol = current_buffer->overlays_before; ol; ol = ol->next)
-    {
-      XSETMISC (tmp, ol);
-      before = Fcons (tmp, before);
-    }
-  for (ol = current_buffer->overlays_after; ol; ol = ol->next)
-    {
-      XSETMISC (tmp, ol);
-      after = Fcons (tmp, after);
-    }
+  for (struct Lisp_Overlay *ol = current_buffer->overlays_before;
+       ol; ol = ol->next)
+    before = Fcons (make_lisp_ptr (ol, Lisp_Vectorlike), before);
+  for (struct Lisp_Overlay *ol = current_buffer->overlays_after;
+       ol; ol = ol->next)
+    after = Fcons (make_lisp_ptr (ol, Lisp_Vectorlike), after);
 
   return Fcons (Fnreverse (before), Fnreverse (after));
 }
@@ -4439,14 +4415,9 @@ void
 report_overlay_modification (Lisp_Object start, Lisp_Object end, bool after,
                             Lisp_Object arg1, Lisp_Object arg2, Lisp_Object 
arg3)
 {
-  Lisp_Object prop, overlay;
-  struct Lisp_Overlay *tail;
   /* True if this change is an insertion.  */
   bool insertion = (after ? XFASTINT (arg3) == 0 : EQ (start, end));
 
-  overlay = Qnil;
-  tail = NULL;
-
   /* We used to run the functions as soon as we found them and only register
      them in last_overlay_modification_hooks for the purpose of the `after'
      case.  But running elisp code as we traverse the list of overlays is
@@ -4460,12 +4431,13 @@ report_overlay_modification (Lisp_Object start, 
Lisp_Object end, bool after,
       /* We are being called before a change.
         Scan the overlays to find the functions to call.  */
       last_overlay_modification_hooks_used = 0;
-      for (tail = current_buffer->overlays_before; tail; tail = tail->next)
+      for (struct Lisp_Overlay *tail = current_buffer->overlays_before;
+          tail; tail = tail->next)
        {
          ptrdiff_t startpos, endpos;
          Lisp_Object ostart, oend;
 
-         XSETMISC (overlay, tail);
+         Lisp_Object overlay = make_lisp_ptr (tail, Lisp_Vectorlike);
 
          ostart = OVERLAY_START (overlay);
          oend = OVERLAY_END (overlay);
@@ -4476,14 +4448,14 @@ report_overlay_modification (Lisp_Object start, 
Lisp_Object end, bool after,
          if (insertion && (XFASTINT (start) == startpos
                            || XFASTINT (end) == startpos))
            {
-             prop = Foverlay_get (overlay, Qinsert_in_front_hooks);
+             Lisp_Object prop = Foverlay_get (overlay, Qinsert_in_front_hooks);
              if (!NILP (prop))
                add_overlay_mod_hooklist (prop, overlay);
            }
          if (insertion && (XFASTINT (start) == endpos
                            || XFASTINT (end) == endpos))
            {
-             prop = Foverlay_get (overlay, Qinsert_behind_hooks);
+             Lisp_Object prop = Foverlay_get (overlay, Qinsert_behind_hooks);
              if (!NILP (prop))
                add_overlay_mod_hooklist (prop, overlay);
            }
@@ -4491,18 +4463,19 @@ report_overlay_modification (Lisp_Object start, 
Lisp_Object end, bool after,
             for both insertion and deletion.  */
          if (XFASTINT (end) > startpos && XFASTINT (start) < endpos)
            {
-             prop = Foverlay_get (overlay, Qmodification_hooks);
+             Lisp_Object prop = Foverlay_get (overlay, Qmodification_hooks);
              if (!NILP (prop))
                add_overlay_mod_hooklist (prop, overlay);
            }
        }
 
-      for (tail = current_buffer->overlays_after; tail; tail = tail->next)
+      for (struct Lisp_Overlay *tail = current_buffer->overlays_after;
+          tail; tail = tail->next)
        {
          ptrdiff_t startpos, endpos;
          Lisp_Object ostart, oend;
 
-         XSETMISC (overlay, tail);
+         Lisp_Object overlay = make_lisp_ptr (tail, Lisp_Vectorlike);
 
          ostart = OVERLAY_START (overlay);
          oend = OVERLAY_END (overlay);
@@ -4513,14 +4486,14 @@ report_overlay_modification (Lisp_Object start, 
Lisp_Object end, bool after,
          if (insertion && (XFASTINT (start) == startpos
                            || XFASTINT (end) == startpos))
            {
-             prop = Foverlay_get (overlay, Qinsert_in_front_hooks);
+             Lisp_Object prop = Foverlay_get (overlay, Qinsert_in_front_hooks);
              if (!NILP (prop))
                add_overlay_mod_hooklist (prop, overlay);
            }
          if (insertion && (XFASTINT (start) == endpos
                            || XFASTINT (end) == endpos))
            {
-             prop = Foverlay_get (overlay, Qinsert_behind_hooks);
+             Lisp_Object prop = Foverlay_get (overlay, Qinsert_behind_hooks);
              if (!NILP (prop))
                add_overlay_mod_hooklist (prop, overlay);
            }
@@ -4528,7 +4501,7 @@ report_overlay_modification (Lisp_Object start, 
Lisp_Object end, bool after,
             for both insertion and deletion.  */
          if (XFASTINT (end) > startpos && XFASTINT (start) < endpos)
            {
-             prop = Foverlay_get (overlay, Qmodification_hooks);
+             Lisp_Object prop = Foverlay_get (overlay, Qmodification_hooks);
              if (!NILP (prop))
                add_overlay_mod_hooklist (prop, overlay);
            }
@@ -4596,16 +4569,13 @@ call_overlay_mod_hooks (Lisp_Object list, Lisp_Object 
overlay, bool after,
 void
 evaporate_overlays (ptrdiff_t pos)
 {
-  Lisp_Object overlay, hit_list;
-  struct Lisp_Overlay *tail;
-
-  hit_list = Qnil;
+  Lisp_Object hit_list = Qnil;
   if (pos <= current_buffer->overlay_center)
-    for (tail = current_buffer->overlays_before; tail; tail = tail->next)
+    for (struct Lisp_Overlay *tail = current_buffer->overlays_before;
+        tail; tail = tail->next)
       {
-       ptrdiff_t endpos;
-       XSETMISC (overlay, tail);
-       endpos = OVERLAY_POSITION (OVERLAY_END (overlay));
+       Lisp_Object overlay = make_lisp_ptr (tail, Lisp_Vectorlike);
+       ptrdiff_t endpos = OVERLAY_POSITION (OVERLAY_END (overlay));
        if (endpos < pos)
          break;
        if (endpos == pos && OVERLAY_POSITION (OVERLAY_START (overlay)) == pos
@@ -4613,11 +4583,11 @@ evaporate_overlays (ptrdiff_t pos)
          hit_list = Fcons (overlay, hit_list);
       }
   else
-    for (tail = current_buffer->overlays_after; tail; tail = tail->next)
+    for (struct Lisp_Overlay *tail = current_buffer->overlays_after;
+        tail; tail = tail->next)
       {
-       ptrdiff_t startpos;
-       XSETMISC (overlay, tail);
-       startpos = OVERLAY_POSITION (OVERLAY_START (overlay));
+       Lisp_Object overlay = make_lisp_ptr (tail, Lisp_Vectorlike);
+       ptrdiff_t startpos = OVERLAY_POSITION (OVERLAY_START (overlay));
        if (startpos > pos)
          break;
        if (startpos == pos && OVERLAY_POSITION (OVERLAY_END (overlay)) == pos
diff --git a/src/data.c b/src/data.c
index aaccb67518..2cef50fe76 100644
--- a/src/data.c
+++ b/src/data.c
@@ -221,27 +221,16 @@ for example, (type-of 1) returns `integer'.  */)
     case Lisp_Cons:
       return Qcons;
 
-    case Lisp_Misc:
-      switch (XMISCTYPE (object))
-       {
-       case Lisp_Misc_Marker:
-         return Qmarker;
-       case Lisp_Misc_Overlay:
-         return Qoverlay;
-        case Lisp_Misc_Finalizer:
-          return Qfinalizer;
-#ifdef HAVE_MODULES
-       case Lisp_Misc_User_Ptr:
-         return Quser_ptr;
-#endif
-       default:
-         emacs_abort ();
-       }
-
     case Lisp_Vectorlike:
       switch (PSEUDOVECTOR_TYPE (XVECTOR (object)))
         {
         case PVEC_NORMAL_VECTOR: return Qvector;
+       case PVEC_MARKER: return Qmarker;
+       case PVEC_OVERLAY: return Qoverlay;
+       case PVEC_FINALIZER: return Qfinalizer;
+#ifdef HAVE_MODULES
+       case PVEC_USER_PTR: return Quser_ptr;
+#endif
         case PVEC_WINDOW_CONFIGURATION: return Qwindow_configuration;
         case PVEC_PROCESS: return Qprocess;
         case PVEC_WINDOW: return Qwindow;
@@ -277,6 +266,7 @@ for example, (type-of 1) returns `integer'.  */)
         case PVEC_MODULE_FUNCTION:
           return Qmodule_function;
         /* "Impossible" cases.  */
+       case PVEC_MISC_PTR:
         case PVEC_XWIDGET:
         case PVEC_OTHER:
         case PVEC_XWIDGET_VIEW:
diff --git a/src/editfns.c b/src/editfns.c
index 0fbc5aad8c..f3e6adb002 100644
--- a/src/editfns.c
+++ b/src/editfns.c
@@ -484,21 +484,18 @@ If you set the marker not to point anywhere, the buffer 
will have no mark.  */)
 static ptrdiff_t
 overlays_around (EMACS_INT pos, Lisp_Object *vec, ptrdiff_t len)
 {
-  Lisp_Object overlay, start, end;
-  struct Lisp_Overlay *tail;
-  ptrdiff_t startpos, endpos;
   ptrdiff_t idx = 0;
 
-  for (tail = current_buffer->overlays_before; tail; tail = tail->next)
+  for (struct Lisp_Overlay *tail = current_buffer->overlays_before;
+       tail; tail = tail->next)
     {
-      XSETMISC (overlay, tail);
-
-      end = OVERLAY_END (overlay);
-      endpos = OVERLAY_POSITION (end);
+      Lisp_Object overlay = make_lisp_ptr (tail, Lisp_Vectorlike);
+      Lisp_Object end = OVERLAY_END (overlay);
+      ptrdiff_t endpos = OVERLAY_POSITION (end);
       if (endpos < pos)
          break;
-      start = OVERLAY_START (overlay);
-      startpos = OVERLAY_POSITION (start);
+      Lisp_Object start = OVERLAY_START (overlay);
+      ptrdiff_t startpos = OVERLAY_POSITION (start);
       if (startpos <= pos)
        {
          if (idx < len)
@@ -508,16 +505,16 @@ overlays_around (EMACS_INT pos, Lisp_Object *vec, 
ptrdiff_t len)
        }
     }
 
-  for (tail = current_buffer->overlays_after; tail; tail = tail->next)
+  for (struct Lisp_Overlay *tail = current_buffer->overlays_after;
+       tail; tail = tail->next)
     {
-      XSETMISC (overlay, tail);
-
-      start = OVERLAY_START (overlay);
-      startpos = OVERLAY_POSITION (start);
+      Lisp_Object overlay = make_lisp_ptr (tail, Lisp_Vectorlike);
+      Lisp_Object start = OVERLAY_START (overlay);
+      ptrdiff_t startpos = OVERLAY_POSITION (start);
       if (pos < startpos)
        break;
-      end = OVERLAY_END (overlay);
-      endpos = OVERLAY_POSITION (end);
+      Lisp_Object end = OVERLAY_END (overlay);
+      ptrdiff_t endpos = OVERLAY_POSITION (end);
       if (pos <= endpos)
        {
          if (idx < len)
diff --git a/src/fns.c b/src/fns.c
index 5247140ead..1e23a78c4b 100644
--- a/src/fns.c
+++ b/src/fns.c
@@ -2285,7 +2285,7 @@ internal_equal (Lisp_Object o1, Lisp_Object o2, enum 
equal_kind equal_kind,
        ht = CALLN (Fmake_hash_table, QCtest, Qeq);
       switch (XTYPE (o1))
        {
-       case Lisp_Cons: case Lisp_Misc: case Lisp_Vectorlike:
+       case Lisp_Cons: case Lisp_Vectorlike:
          {
            struct Lisp_Hash_Table *h = XHASH_TABLE (ht);
            EMACS_UINT hash;
@@ -2342,29 +2342,6 @@ internal_equal (Lisp_Object o1, Lisp_Object o2, enum 
equal_kind equal_kind,
       depth++;
       goto tail_recurse;
 
-    case Lisp_Misc:
-      if (XMISCTYPE (o1) != XMISCTYPE (o2))
-       return false;
-      if (OVERLAYP (o1))
-       {
-         if (!internal_equal (OVERLAY_START (o1), OVERLAY_START (o2),
-                              equal_kind, depth + 1, ht)
-             || !internal_equal (OVERLAY_END (o1), OVERLAY_END (o2),
-                                 equal_kind, depth + 1, ht))
-           return false;
-         o1 = XOVERLAY (o1)->plist;
-         o2 = XOVERLAY (o2)->plist;
-         depth++;
-         goto tail_recurse;
-       }
-      if (MARKERP (o1))
-       {
-         return (XMARKER (o1)->buffer == XMARKER (o2)->buffer
-                 && (XMARKER (o1)->buffer == 0
-                     || XMARKER (o1)->bytepos == XMARKER (o2)->bytepos));
-       }
-      break;
-
     case Lisp_Vectorlike:
       {
        register int i;
@@ -2374,6 +2351,24 @@ internal_equal (Lisp_Object o1, Lisp_Object o2, enum 
equal_kind equal_kind,
           same size.  */
        if (ASIZE (o2) != size)
          return false;
+       if (OVERLAYP (o1))
+         {
+           if (!internal_equal (OVERLAY_START (o1), OVERLAY_START (o2),
+                                equal_kind, depth + 1, ht)
+               || !internal_equal (OVERLAY_END (o1), OVERLAY_END (o2),
+                                   equal_kind, depth + 1, ht))
+             return false;
+           o1 = XOVERLAY (o1)->plist;
+           o2 = XOVERLAY (o2)->plist;
+           depth++;
+           goto tail_recurse;
+         }
+       if (MARKERP (o1))
+         {
+           return (XMARKER (o1)->buffer == XMARKER (o2)->buffer
+                   && (XMARKER (o1)->buffer == 0
+                       || XMARKER (o1)->bytepos == XMARKER (o2)->bytepos));
+         }
        /* Boolvectors are compared much like strings.  */
        if (BOOL_VECTOR_P (o1))
          {
@@ -4451,7 +4446,6 @@ sxhash (Lisp_Object obj, int depth)
       hash = XUINT (obj);
       break;
 
-    case Lisp_Misc:
     case Lisp_Symbol:
       hash = XHASH (obj);
       break;
diff --git a/src/lisp.h b/src/lisp.h
index bdece817bd..c559377288 100644
--- a/src/lisp.h
+++ b/src/lisp.h
@@ -360,8 +360,6 @@ typedef EMACS_INT Lisp_Word;
 #define lisp_h_EQ(x, y) (XLI (x) == XLI (y))
 #define lisp_h_FLOATP(x) (XTYPE (x) == Lisp_Float)
 #define lisp_h_INTEGERP(x) ((XTYPE (x) & (Lisp_Int0 | ~Lisp_Int1)) == 
Lisp_Int0)
-#define lisp_h_MARKERP(x) (MISCP (x) && XMISCTYPE (x) == Lisp_Misc_Marker)
-#define lisp_h_MISCP(x) (XTYPE (x) == Lisp_Misc)
 #define lisp_h_NILP(x) EQ (x, Qnil)
 #define lisp_h_SET_SYMBOL_VAL(sym, v) \
    (eassert ((sym)->u.s.redirect == SYMBOL_PLAINVAL), \
@@ -425,8 +423,6 @@ typedef EMACS_INT Lisp_Word;
 # define EQ(x, y) lisp_h_EQ (x, y)
 # define FLOATP(x) lisp_h_FLOATP (x)
 # define INTEGERP(x) lisp_h_INTEGERP (x)
-# define MARKERP(x) lisp_h_MARKERP (x)
-# define MISCP(x) lisp_h_MISCP (x)
 # define NILP(x) lisp_h_NILP (x)
 # define SET_SYMBOL_VAL(sym, v) lisp_h_SET_SYMBOL_VAL (sym, v)
 # define SYMBOL_CONSTANT_P(sym) lisp_h_SYMBOL_CONSTANT_P (sym)
@@ -477,10 +473,6 @@ enum Lisp_Type
     /* Symbol.  XSYMBOL (object) points to a struct Lisp_Symbol.  */
     Lisp_Symbol = 0,
 
-    /* Miscellaneous.  XMISC (object) points to a union Lisp_Misc,
-       whose first member indicates the subtype.  */
-    Lisp_Misc = 1,
-
     /* Integer.  XINT (obj) is the integer value.  */
     Lisp_Int0 = 2,
     Lisp_Int1 = USE_LSB_TAG ? 6 : 3,
@@ -501,25 +493,6 @@ enum Lisp_Type
     Lisp_Float = 7
   };
 
-/* This is the set of data types that share a common structure.
-   The first member of the structure is a type code from this set.
-   The enum values are arbitrary, but we'll use large numbers to make it
-   more likely that we'll spot the error if a random word in memory is
-   mistakenly interpreted as a Lisp_Misc.  */
-enum Lisp_Misc_Type
-  {
-    Lisp_Misc_Free = 0x5eab,
-    Lisp_Misc_Marker,
-    Lisp_Misc_Overlay,
-    Lisp_Misc_Finalizer,
-    Lisp_Misc_Ptr,
-#ifdef HAVE_MODULES
-    Lisp_Misc_User_Ptr,
-#endif
-    /* This is not a type code.  It is for range checking.  */
-    Lisp_Misc_Limit
-  };
-
 /* These are the types of forwarding objects used in the value slot
    of symbols for special built-in variables whose value is stored in
    C variables.  */
@@ -533,14 +506,12 @@ enum Lisp_Fwd_Type
   };
 
 /* If you want to define a new Lisp data type, here are some
-   instructions.  See the thread at
-   https://lists.gnu.org/r/emacs-devel/2012-10/msg00561.html
-   for more info.
+   instructions.
 
    First, there are already a couple of Lisp types that can be used if
    your new type does not need to be exposed to Lisp programs nor
-   displayed to users.  These are Lisp_Misc_Ptr, a Lisp_Misc
-   subtype; and PVEC_OTHER, a kind of vectorlike object.  The former
+   displayed to users.  These are Lisp_Misc_Ptr and PVEC_OTHER,
+   which are both vectorlike objects.  The former
    is suitable for stashing a pointer in a Lisp object; the pointer
    might be to some low-level C object that contains auxiliary
    information.  The latter is useful for vector-like Lisp objects
@@ -551,30 +522,14 @@ enum Lisp_Fwd_Type
    These two types don't look pretty when printed, so they are
    unsuitable for Lisp objects that can be exposed to users.
 
-   To define a new data type, add one more Lisp_Misc subtype or one
-   more pseudovector subtype.  Pseudovectors are more suitable for
-   objects with several slots that need to support fast random access,
-   while Lisp_Misc types are for everything else.  A pseudovector object
-   provides one or more slots for Lisp objects, followed by struct
-   members that are accessible only from C.  A Lisp_Misc object is a
-   wrapper for a C struct that can contain anything you like.
+   To define a new data type, add a pseudovector subtype by extending
+   the pvec_type enumeration.  A pseudovector provides one or more
+   slots for Lisp objects, followed by struct members that are
+   accessible only from C.
 
    There is no way to explicitly free a Lisp Object; only the garbage
    collector frees them.
 
-   To add a new pseudovector type, extend the pvec_type enumeration;
-   to add a new Lisp_Misc, extend the Lisp_Misc_Type enumeration.
-
-   For a Lisp_Misc, you will also need to add your entry to union
-   Lisp_Misc, but make sure the first word has the same structure as
-   the others, starting with a 16-bit member of the Lisp_Misc_Type
-   enumeration and a 1-bit GC markbit.  Also make sure the overall
-   size of the union is not increased by your addition.  The latter
-   requirement is to keep Lisp_Misc objects small enough, so they
-   are handled faster: since all Lisp_Misc types use the same space,
-   enlarging any of them will affect all the rest.  If you really
-   need a larger object, it is best to use Lisp_Vectorlike instead.
-
    For a new pseudovector, it's highly desirable to limit the size
    of your data type by VBLOCK_BYTES_MAX bytes (defined in alloc.c).
    Otherwise you will need to change sweep_vectors (also in alloc.c).
@@ -967,6 +922,13 @@ enum pvec_type
 {
   PVEC_NORMAL_VECTOR,
   PVEC_FREE,
+  PVEC_MARKER,
+  PVEC_OVERLAY,
+  PVEC_FINALIZER,
+  PVEC_MISC_PTR,
+#ifdef HAVE_MODULES
+  PVEC_USER_PTR,
+#endif
   PVEC_PROCESS,
   PVEC_FRAME,
   PVEC_WINDOW,
@@ -1167,7 +1129,6 @@ INLINE bool
 #define XSETSTRING(a, b) ((a) = make_lisp_ptr (b, Lisp_String))
 #define XSETSYMBOL(a, b) ((a) = make_lisp_symbol (b))
 #define XSETFLOAT(a, b) ((a) = make_lisp_ptr (b, Lisp_Float))
-#define XSETMISC(a, b) ((a) = make_lisp_ptr (b, Lisp_Misc))
 
 /* Pseudovector types.  */
 
@@ -2267,46 +2228,10 @@ SXHASH_REDUCE (EMACS_UINT x)
   return (x ^ x >> (EMACS_INT_WIDTH - FIXNUM_BITS)) & INTMASK;
 }
 
-/* These structures are used for various misc types.  */
-
-struct Lisp_Misc_Any           /* Supertype of all Misc types.  */
-{
-  ENUM_BF (Lisp_Misc_Type) type : 16;          /* = Lisp_Misc_??? */
-  bool_bf gcmarkbit : 1;
-  unsigned spacer : 15;
-};
-
-INLINE bool
-(MISCP) (Lisp_Object x)
-{
-  return lisp_h_MISCP (x);
-}
-
-INLINE struct Lisp_Misc_Any *
-XMISCANY (Lisp_Object a)
-{
-  eassert (MISCP (a));
-  return XUNTAG (a, Lisp_Misc, struct Lisp_Misc_Any);
-}
-
-INLINE enum Lisp_Misc_Type
-XMISCTYPE (Lisp_Object a)
-{
-  return XMISCANY (a)->type;
-}
-
 struct Lisp_Marker
 {
-  ENUM_BF (Lisp_Misc_Type) type : 16;          /* = Lisp_Misc_Marker */
-  bool_bf gcmarkbit : 1;
-  unsigned spacer : 13;
-  /* This flag is temporarily used in the functions
-     decode/encode_coding_object to record that the marker position
-     must be adjusted after the conversion.  */
-  bool_bf need_adjustment : 1;
-  /* True means normal insertion at the marker's position
-     leaves the marker after the inserted text.  */
-  bool_bf insertion_type : 1;
+  union vectorlike_header header;
+
   /* This is the buffer that the marker points into, or 0 if it points nowhere.
      Note: a chain of markers can contain markers pointing into different
      buffers (the chain is per buffer_text rather than per buffer, so it's
@@ -2319,6 +2244,14 @@ struct Lisp_Marker
      */
   struct buffer *buffer;
 
+  /* This flag is temporarily used in the functions
+     decode/encode_coding_object to record that the marker position
+     must be adjusted after the conversion.  */
+  bool_bf need_adjustment : 1;
+  /* True means normal insertion at the marker's position
+     leaves the marker after the inserted text.  */
+  bool_bf insertion_type : 1;
+
   /* The remaining fields are meaningless in a marker that
      does not point anywhere.  */
 
@@ -2351,20 +2284,16 @@ struct Lisp_Overlay
    I.e. 9words plus 2 bits, 3words of which are for external linked lists.
 */
   {
-    ENUM_BF (Lisp_Misc_Type) type : 16;        /* = Lisp_Misc_Overlay */
-    bool_bf gcmarkbit : 1;
-    unsigned spacer : 15;
-    struct Lisp_Overlay *next;
+    union vectorlike_header header;
     Lisp_Object start;
     Lisp_Object end;
     Lisp_Object plist;
+    struct Lisp_Overlay *next;
   };
 
 struct Lisp_Misc_Ptr
   {
-    ENUM_BF (Lisp_Misc_Type) type : 16;        /* = Lisp_Misc_Ptr */
-    bool_bf gcmarkbit : 1;
-    unsigned spacer : 15;
+    union vectorlike_header header;
     void *pointer;
   };
 
@@ -2382,7 +2311,7 @@ extern Lisp_Object make_misc_ptr (void *);
    C code, it should not be given a mint_ptr generated from Lisp code
    as that would allow Lisp code to coin pointers from integers and
    could lead to crashes.  To package a C pointer into a Lisp-visible
-   object you can put the pointer into a Lisp_Misc object instead; see
+   object you can put the pointer into a pseudovector instead; see
    Lisp_User_Ptr for an example.  */
 
 INLINE Lisp_Object
@@ -2395,7 +2324,7 @@ make_mint_ptr (void *a)
 INLINE bool
 mint_ptrp (Lisp_Object x)
 {
-  return INTEGERP (x) || (MISCP (x) && XMISCTYPE (x) == Lisp_Misc_Ptr);
+  return INTEGERP (x) || PSEUDOVECTORP (x, PVEC_MISC_PTR);
 }
 
 INLINE void *
@@ -2404,16 +2333,13 @@ xmint_pointer (Lisp_Object a)
   eassert (mint_ptrp (a));
   if (INTEGERP (a))
     return XINTPTR (a);
-  return XUNTAG (a, Lisp_Misc, struct Lisp_Misc_Ptr)->pointer;
+  return XUNTAG (a, Lisp_Vectorlike, struct Lisp_Misc_Ptr)->pointer;
 }
 
 #ifdef HAVE_MODULES
 struct Lisp_User_Ptr
 {
-  ENUM_BF (Lisp_Misc_Type) type : 16;       /* = Lisp_Misc_User_Ptr */
-  bool_bf gcmarkbit : 1;
-  unsigned spacer : 15;
-
+  union vectorlike_header header;
   void (*finalizer) (void *);
   void *p;
 };
@@ -2422,100 +2348,69 @@ struct Lisp_User_Ptr
 /* A finalizer sentinel.  */
 struct Lisp_Finalizer
   {
-    struct Lisp_Misc_Any base;
-
-    /* Circular list of all active weak references.  */
-    struct Lisp_Finalizer *prev;
-    struct Lisp_Finalizer *next;
+    union vectorlike_header header;
 
     /* Call FUNCTION when the finalizer becomes unreachable, even if
        FUNCTION contains a reference to the finalizer; i.e., call
        FUNCTION when it is reachable _only_ through finalizers.  */
     Lisp_Object function;
+
+    /* Circular list of all active weak references.  */
+    struct Lisp_Finalizer *prev;
+    struct Lisp_Finalizer *next;
   };
 
 INLINE bool
 FINALIZERP (Lisp_Object x)
 {
-  return MISCP (x) && XMISCTYPE (x) == Lisp_Misc_Finalizer;
+  return PSEUDOVECTORP (x, PVEC_FINALIZER);
 }
 
 INLINE struct Lisp_Finalizer *
 XFINALIZER (Lisp_Object a)
 {
   eassert (FINALIZERP (a));
-  return XUNTAG (a, Lisp_Misc, struct Lisp_Finalizer);
-}
-
-/* A miscellaneous object, when it's on the free list.  */
-struct Lisp_Free
-  {
-    ENUM_BF (Lisp_Misc_Type) type : 16;        /* = Lisp_Misc_Free */
-    bool_bf gcmarkbit : 1;
-    unsigned spacer : 15;
-    union Lisp_Misc *chain;
-  };
-
-/* To get the type field of a union Lisp_Misc, use XMISCTYPE.
-   It uses one of these struct subtypes to get the type field.  */
-
-union Lisp_Misc
-  {
-    struct Lisp_Misc_Any u_any;           /* Supertype of all Misc types.  */
-    struct Lisp_Free u_free;
-    struct Lisp_Marker u_marker;
-    struct Lisp_Overlay u_overlay;
-    struct Lisp_Finalizer u_finalizer;
-    struct Lisp_Misc_Ptr u_misc_ptr;
-#ifdef HAVE_MODULES
-    struct Lisp_User_Ptr u_user_ptr;
-#endif
-  };
-
-INLINE union Lisp_Misc *
-XMISC (Lisp_Object a)
-{
-  return XUNTAG (a, Lisp_Misc, union Lisp_Misc);
+  return XUNTAG (a, Lisp_Vectorlike, struct Lisp_Finalizer);
 }
 
 INLINE bool
-(MARKERP) (Lisp_Object x)
+MARKERP (Lisp_Object x)
 {
-  return lisp_h_MARKERP (x);
+  return PSEUDOVECTORP (x, PVEC_MARKER);
 }
 
 INLINE struct Lisp_Marker *
 XMARKER (Lisp_Object a)
 {
   eassert (MARKERP (a));
-  return XUNTAG (a, Lisp_Misc, struct Lisp_Marker);
+  return XUNTAG (a, Lisp_Vectorlike, struct Lisp_Marker);
 }
 
 INLINE bool
 OVERLAYP (Lisp_Object x)
 {
-  return MISCP (x) && XMISCTYPE (x) == Lisp_Misc_Overlay;
+  return PSEUDOVECTORP (x, PVEC_OVERLAY);
 }
 
 INLINE struct Lisp_Overlay *
 XOVERLAY (Lisp_Object a)
 {
   eassert (OVERLAYP (a));
-  return XUNTAG (a, Lisp_Misc, struct Lisp_Overlay);
+  return XUNTAG (a, Lisp_Vectorlike, struct Lisp_Overlay);
 }
 
 #ifdef HAVE_MODULES
 INLINE bool
 USER_PTRP (Lisp_Object x)
 {
-  return MISCP (x) && XMISCTYPE (x) == Lisp_Misc_User_Ptr;
+  return PSEUDOVECTORP (x, PVEC_USER_PTR);
 }
 
 INLINE struct Lisp_User_Ptr *
 XUSER_PTR (Lisp_Object a)
 {
   eassert (USER_PTRP (a));
-  return XUNTAG (a, Lisp_Misc, struct Lisp_User_Ptr);
+  return XUNTAG (a, Lisp_Vectorlike, struct Lisp_User_Ptr);
 }
 #endif
 
diff --git a/src/print.c b/src/print.c
index 34c7fa12b6..cb35abfbfc 100644
--- a/src/print.c
+++ b/src/print.c
@@ -1367,6 +1367,67 @@ print_vectorlike (Lisp_Object obj, Lisp_Object 
printcharfun, bool escapeflag,
 {
   switch (PSEUDOVECTOR_TYPE (XVECTOR (obj)))
     {
+    case PVEC_MARKER:
+      print_c_string ("#<marker ", printcharfun);
+      /* Do you think this is necessary?  */
+      if (XMARKER (obj)->insertion_type != 0)
+       print_c_string ("(moves after insertion) ", printcharfun);
+      if (! XMARKER (obj)->buffer)
+       print_c_string ("in no buffer", printcharfun);
+      else
+       {
+         int len = sprintf (buf, "at %"pD"d in ", marker_position (obj));
+         strout (buf, len, len, printcharfun);
+         print_string (BVAR (XMARKER (obj)->buffer, name), printcharfun);
+       }
+      printchar ('>', printcharfun);
+      break;
+
+    case PVEC_OVERLAY:
+      print_c_string ("#<overlay ", printcharfun);
+      if (! XMARKER (OVERLAY_START (obj))->buffer)
+       print_c_string ("in no buffer", printcharfun);
+      else
+       {
+         int len = sprintf (buf, "from %"pD"d to %"pD"d in ",
+                            marker_position (OVERLAY_START (obj)),
+                            marker_position (OVERLAY_END   (obj)));
+         strout (buf, len, len, printcharfun);
+         print_string (BVAR (XMARKER (OVERLAY_START (obj))->buffer, name),
+                       printcharfun);
+       }
+      printchar ('>', printcharfun);
+      break;
+
+#ifdef HAVE_MODULES
+    case PVEC_USER_PTR:
+      {
+       print_c_string ("#<user-ptr ", printcharfun);
+       int i = sprintf (buf, "ptr=%p finalizer=%p",
+                        XUSER_PTR (obj)->p,
+                        XUSER_PTR (obj)->finalizer);
+       strout (buf, i, i, printcharfun);
+       printchar ('>', printcharfun);
+      }
+      break;
+#endif
+
+    case PVEC_FINALIZER:
+      print_c_string ("#<finalizer", printcharfun);
+      if (NILP (XFINALIZER (obj)->function))
+       print_c_string (" used", printcharfun);
+      printchar ('>', printcharfun);
+      break;
+
+    case PVEC_MISC_PTR:
+      {
+       /* This shouldn't happen in normal usage, but let's
+          print it anyway for the benefit of the debugger.  */
+       int i = sprintf (buf, "#<ptr %p>", xmint_pointer (obj));
+       strout (buf, i, i, printcharfun);
+      }
+      break;
+
     case PVEC_PROCESS:
       if (escapeflag)
        {
@@ -2096,94 +2157,16 @@ print_object (Lisp_Object obj, Lisp_Object 
printcharfun, bool escapeflag)
       break;
 
     case Lisp_Vectorlike:
-      if (! print_vectorlike (obj, printcharfun, escapeflag, buf))
-       goto badtype;
-      break;
-
-    case Lisp_Misc:
-      switch (XMISCTYPE (obj))
-       {
-       case Lisp_Misc_Marker:
-         print_c_string ("#<marker ", printcharfun);
-         /* Do you think this is necessary?  */
-         if (XMARKER (obj)->insertion_type != 0)
-           print_c_string ("(moves after insertion) ", printcharfun);
-         if (! XMARKER (obj)->buffer)
-           print_c_string ("in no buffer", printcharfun);
-         else
-           {
-             int len = sprintf (buf, "at %"pD"d in ", marker_position (obj));
-             strout (buf, len, len, printcharfun);
-             print_string (BVAR (XMARKER (obj)->buffer, name), printcharfun);
-           }
-         printchar ('>', printcharfun);
-         break;
-
-       case Lisp_Misc_Overlay:
-         print_c_string ("#<overlay ", printcharfun);
-         if (! XMARKER (OVERLAY_START (obj))->buffer)
-           print_c_string ("in no buffer", printcharfun);
-         else
-           {
-             int len = sprintf (buf, "from %"pD"d to %"pD"d in ",
-                                marker_position (OVERLAY_START (obj)),
-                                marker_position (OVERLAY_END   (obj)));
-             strout (buf, len, len, printcharfun);
-             print_string (BVAR (XMARKER (OVERLAY_START (obj))->buffer, name),
-                           printcharfun);
-           }
-         printchar ('>', printcharfun);
-          break;
-
-#ifdef HAVE_MODULES
-       case Lisp_Misc_User_Ptr:
-         {
-           print_c_string ("#<user-ptr ", printcharfun);
-           int i = sprintf (buf, "ptr=%p finalizer=%p",
-                            XUSER_PTR (obj)->p,
-                            XUSER_PTR (obj)->finalizer);
-           strout (buf, i, i, printcharfun);
-           printchar ('>', printcharfun);
-           break;
-         }
-#endif
-
-        case Lisp_Misc_Finalizer:
-          print_c_string ("#<finalizer", printcharfun);
-          if (NILP (XFINALIZER (obj)->function))
-            print_c_string (" used", printcharfun);
-         printchar ('>', printcharfun);
-          break;
-
-         /* Remaining cases shouldn't happen in normal usage, but let's
-            print them anyway for the benefit of the debugger.  */
-
-       case Lisp_Misc_Free:
-         print_c_string ("#<misc free cell>", printcharfun);
-         break;
-
-       case Lisp_Misc_Ptr:
-         {
-           int i = sprintf (buf, "#<ptr %p>", xmint_pointer (obj));
-           strout (buf, i, i, printcharfun);
-         }
-         break;
-
-       default:
-         goto badtype;
-       }
-      break;
-
+      if (print_vectorlike (obj, printcharfun, escapeflag, buf))
+       break;
+      FALLTHROUGH;
     default:
-    badtype:
       {
        int len;
        /* We're in trouble if this happens!
           Probably should just emacs_abort ().  */
        print_c_string ("#<EMACS BUG: INVALID DATATYPE ", printcharfun);
-       if (MISCP (obj))
-         len = sprintf (buf, "(MISC 0x%04x)", (unsigned) XMISCTYPE (obj));
-       else if (VECTORLIKEP (obj))
+       if (VECTORLIKEP (obj))
          len = sprintf (buf, "(PVEC 0x%08zx)", (size_t) ASIZE (obj));
        else
          len = sprintf (buf, "(0x%02x)", (unsigned) XTYPE (obj));
diff --git a/src/undo.c b/src/undo.c
index c34faa4272..3af4898e01 100644
--- a/src/undo.c
+++ b/src/undo.c
@@ -126,15 +126,11 @@ record_insert (ptrdiff_t beg, ptrdiff_t length)
 static void
 record_marker_adjustments (ptrdiff_t from, ptrdiff_t to)
 {
-  Lisp_Object marker;
-  register struct Lisp_Marker *m;
-  register ptrdiff_t charpos, adjustment;
-
-  prepare_record();
+  prepare_record ();
 
-  for (m = BUF_MARKERS (current_buffer); m; m = m->next)
+  for (struct Lisp_Marker *m = BUF_MARKERS (current_buffer); m; m = m->next)
     {
-      charpos = m->charpos;
+      ptrdiff_t charpos = m->charpos;
       eassert (charpos <= Z);
 
       if (from <= charpos && charpos <= to)
@@ -146,11 +142,11 @@ record_marker_adjustments (ptrdiff_t from, ptrdiff_t to)
              insertion_type t markers will automatically move forward
              upon re-inserting the deleted text, so we have to arrange
              for them to move backward to the correct position.  */
-          adjustment = (m->insertion_type ? to : from) - charpos;
+         ptrdiff_t adjustment = (m->insertion_type ? to : from) - charpos;
 
           if (adjustment)
             {
-              XSETMISC (marker, m);
+             Lisp_Object marker = make_lisp_ptr (m, Lisp_Vectorlike);
               bset_undo_list
                 (current_buffer,
                  Fcons (Fcons (marker, make_number (adjustment)),
diff --git a/src/xdisp.c b/src/xdisp.c
index 956535c2db..3f51b9c315 100644
--- a/src/xdisp.c
+++ b/src/xdisp.c
@@ -5819,11 +5819,7 @@ compare_overlay_entries (const void *e1, const void *e2)
 static void
 load_overlay_strings (struct it *it, ptrdiff_t charpos)
 {
-  Lisp_Object overlay, window, str, invisible;
-  struct Lisp_Overlay *ov;
-  ptrdiff_t start, end;
-  ptrdiff_t n = 0, i, j;
-  int invis;
+  ptrdiff_t n = 0;
   struct overlay_entry entriesbuf[20];
   ptrdiff_t size = ARRAYELTS (entriesbuf);
   struct overlay_entry *entries = entriesbuf;
@@ -5859,12 +5855,13 @@ load_overlay_strings (struct it *it, ptrdiff_t charpos)
   while (false)
 
   /* Process overlay before the overlay center.  */
-  for (ov = current_buffer->overlays_before; ov; ov = ov->next)
+  for (struct Lisp_Overlay *ov = current_buffer->overlays_before;
+       ov; ov = ov->next)
     {
-      XSETMISC (overlay, ov);
+      Lisp_Object overlay = make_lisp_ptr (ov, Lisp_Vectorlike);
       eassert (OVERLAYP (overlay));
-      start = OVERLAY_POSITION (OVERLAY_START (overlay));
-      end = OVERLAY_POSITION (OVERLAY_END (overlay));
+      ptrdiff_t start = OVERLAY_POSITION (OVERLAY_START (overlay));
+      ptrdiff_t end = OVERLAY_POSITION (OVERLAY_END (overlay));
 
       if (end < charpos)
        break;
@@ -5875,17 +5872,18 @@ load_overlay_strings (struct it *it, ptrdiff_t charpos)
        continue;
 
       /* Skip this overlay if it doesn't apply to IT->w.  */
-      window = Foverlay_get (overlay, Qwindow);
+      Lisp_Object window = Foverlay_get (overlay, Qwindow);
       if (WINDOWP (window) && XWINDOW (window) != it->w)
        continue;
 
       /* If the text ``under'' the overlay is invisible, both before-
         and after-strings from this overlay are visible; start and
         end position are indistinguishable.  */
-      invisible = Foverlay_get (overlay, Qinvisible);
-      invis = TEXT_PROP_MEANS_INVISIBLE (invisible);
+      Lisp_Object invisible = Foverlay_get (overlay, Qinvisible);
+      int invis = TEXT_PROP_MEANS_INVISIBLE (invisible);
 
       /* If overlay has a non-empty before-string, record it.  */
+      Lisp_Object str;
       if ((start == charpos || (end == charpos && invis != 0))
          && (str = Foverlay_get (overlay, Qbefore_string), STRINGP (str))
          && SCHARS (str))
@@ -5899,12 +5897,13 @@ load_overlay_strings (struct it *it, ptrdiff_t charpos)
     }
 
   /* Process overlays after the overlay center.  */
-  for (ov = current_buffer->overlays_after; ov; ov = ov->next)
+  for (struct Lisp_Overlay *ov = current_buffer->overlays_after;
+       ov; ov = ov->next)
     {
-      XSETMISC (overlay, ov);
+      Lisp_Object overlay = make_lisp_ptr (ov, Lisp_Vectorlike);
       eassert (OVERLAYP (overlay));
-      start = OVERLAY_POSITION (OVERLAY_START (overlay));
-      end = OVERLAY_POSITION (OVERLAY_END (overlay));
+      ptrdiff_t start = OVERLAY_POSITION (OVERLAY_START (overlay));
+      ptrdiff_t end = OVERLAY_POSITION (OVERLAY_END (overlay));
 
       if (start > charpos)
        break;
@@ -5915,16 +5914,17 @@ load_overlay_strings (struct it *it, ptrdiff_t charpos)
        continue;
 
       /* Skip this overlay if it doesn't apply to IT->w.  */
-      window = Foverlay_get (overlay, Qwindow);
+      Lisp_Object window = Foverlay_get (overlay, Qwindow);
       if (WINDOWP (window) && XWINDOW (window) != it->w)
        continue;
 
       /* If the text ``under'' the overlay is invisible, it has a zero
         dimension, and both before- and after-strings apply.  */
-      invisible = Foverlay_get (overlay, Qinvisible);
-      invis = TEXT_PROP_MEANS_INVISIBLE (invisible);
+      Lisp_Object invisible = Foverlay_get (overlay, Qinvisible);
+      int invis = TEXT_PROP_MEANS_INVISIBLE (invisible);
 
       /* If overlay has a non-empty before-string, record it.  */
+      Lisp_Object str;
       if ((start == charpos || (end == charpos && invis != 0))
          && (str = Foverlay_get (overlay, Qbefore_string), STRINGP (str))
          && SCHARS (str))
@@ -5950,12 +5950,11 @@ load_overlay_strings (struct it *it, ptrdiff_t charpos)
   /* IT->current.overlay_string_index is the number of overlay strings
      that have already been consumed by IT.  Copy some of the
      remaining overlay strings to IT->overlay_strings.  */
-  i = 0;
-  j = it->current.overlay_string_index;
-  while (i < OVERLAY_STRING_CHUNK_SIZE && j < n)
+  ptrdiff_t j = it->current.overlay_string_index;
+  for (ptrdiff_t i = 0; i < OVERLAY_STRING_CHUNK_SIZE && j < n; i++, j++)
     {
       it->overlay_strings[i] = entries[j].string;
-      it->string_overlays[i++] = entries[j++].overlay;
+      it->string_overlays[i] = entries[j].overlay;
     }
 
   CHECK_IT (it);
-- 
2.17.1






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