Turn misc objects into pseudovectors

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 (Bug#32405).
* 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)
(Lisp_Misc_Bignum)
(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_bignum_str, make_number, make_pure_bignum)
(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, BIGNUMP, XBIGNUM):
* 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_BIGNUM, 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_Bignum, 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.

1 files changed, 22 insertions, 23 deletions

diff --git a/src/xdisp.c b/src/xdisp.c
index 76fde99f323..0835ccafd4d 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);