Merge from origin/emacs-27

44c0e074f7 * doc/emacs/buffers.texi (Icomplete): Mention icomplete-mi...
68b6dad1d8 Be more aggressive in marking objects during GC
36f508f589 ; * src/xdisp.c (find_last_unchanged_at_beg_row): Fix a typo.
cc340da1fe Fix bug #41618 "(byte-compile 'foo) errors when foo is a m...
41232e6797 Avoid crashes due to bidi cache being reset during redisplay
f72bb4ce36 * lisp/tab-bar.el (switch-to-buffer-other-tab): Normalize ...
d3e0023aaa ; * etc/TODO: Fix formatting.  (Bug#41497)
a8ad94cd2f Fix mingw.org's MinGW GCC 9 warning about 'execve'

# Conflicts:
#	lisp/tab-bar.el
#	nt/inc/ms-w32.h
#	src/alloc.c

doc/emacs/buffers.texi

@@ -741,7 +741,14 @@ Ido'').  Among other things, in Fido mode, @kbd{C-s} and @kbd{C-r} are
 also used to rotate the completions list, @kbd{C-k} can be used to
 delete files and kill buffers in-list.  Another noteworthy aspect is
 that @code{flex} is used as the default completion style
-(@pxref{Completion Styles}).
+(@pxref{Completion Styles}).  To change this, add the following to
+your initialization file (@pxref{Init File}):
+
+@example
+(defun my-icomplete-styles ()
+  (setq-local completion-styles '(initials flex)))
+(add-hook 'icomplete-minibuffer-setup-hook 'my-icomplete-styles)
+@end example
 
   To enable Fido mode, type @kbd{M-x fido-mode}, or customize
 the variable @code{fido-mode} to @code{t} (@pxref{Easy

lisp/emacs-lisp/bytecomp.el

@@ -2755,14 +2755,15 @@ If FORM is a lambda or a macro, byte-compile it as a function."
         ;; Expand macros.
         (setq fun (byte-compile-preprocess fun))
         (setq fun (byte-compile-top-level fun nil 'eval))
-        (if macro (push 'macro fun))
         (if (symbolp form)
             ;; byte-compile-top-level returns an *expression* equivalent to the
             ;; `fun' expression, so we need to evaluate it, tho normally
             ;; this is not needed because the expression is just a constant
             ;; byte-code object, which is self-evaluating.
-            (fset form (eval fun t))
-          fun)))))))
+            (setq fun (eval fun t)))
+        (if macro (push 'macro fun))
+        (if (symbolp form) (fset form fun))
+        fun))))))
 
 (defun byte-compile-sexp (sexp)
   "Compile and return SEXP."

lisp/progmodes/cc-mode.el

@@ -1621,7 +1621,7 @@ Note that the style variables are always made local to the buffer."
       (goto-char (1+ end))		; After the \
       ;; Search forward for EOLL
       (setq lim (re-search-forward "\\(?:\\\\\\(?:.\\|\n\\)\\|[^\\\n\r]\\)*"
-       				   nil t))
+				   nil t))
       (goto-char (1+ end))
       (when (c-search-forward-char-property-with-value-on-char
 	     'syntax-table '(15) ?\" lim)

lisp/tab-bar.el

@@ -1554,9 +1554,10 @@ indirectly called by the latter."
 Like \\[switch-to-buffer-other-frame] (which see), but creates a new tab."
   (interactive
    (list (read-buffer-to-switch "Switch to buffer in other tab: ")))
-  (display-buffer buffer-or-name '((display-buffer-in-tab)
-                                   (inhibit-same-window . nil)
-                                   (reusable-frames . t))
+  (display-buffer (window-normalize-buffer-to-switch-to buffer-or-name)
+                  '((display-buffer-in-tab)
+                    (inhibit-same-window . nil)
+                    (reusable-frames . t))
                   norecord))
 
 (defun find-file-other-tab (filename &optional wildcards)

src/alloc.c

@@ -4687,35 +4687,6 @@ mark_maybe_objects (Lisp_Object const *array, ptrdiff_t nelts)
     mark_maybe_object (*array);
 }
 
-/* A lower bound on the alignment of Lisp objects that need marking.
-   Although 1 is safe, higher values speed up mark_maybe_pointer.
-   If USE_LSB_TAG, this value is typically GCALIGNMENT; otherwise,
-   it's determined by the natural alignment of Lisp structs.
-   All vectorlike objects have alignment at least that of union
-   vectorlike_header and it's unlikely they all have alignment greater,
-   so use the union as a safe and likely-accurate standin for
-   vectorlike objects.  */
-
-enum { GC_OBJECT_ALIGNMENT_MINIMUM
-         = max (GCALIGNMENT,
-		min (alignof (union vectorlike_header),
-		     min (min (alignof (struct Lisp_Cons),
-			       alignof (struct Lisp_Float)),
-			  min (alignof (struct Lisp_String),
-			       alignof (struct Lisp_Symbol))))) };
-
-/* Return true if P might point to Lisp data that can be garbage
-   collected, and false otherwise (i.e., false if it is easy to see
-   that P cannot point to Lisp data that can be garbage collected).
-   Symbols are implemented via offsets not pointers, but the offsets
-   are also multiples of GC_OBJECT_ALIGNMENT_MINIMUM.  */
-
-static bool
-maybe_lisp_pointer (void *p)
-{
-  return (uintptr_t) p % GC_OBJECT_ALIGNMENT_MINIMUM == 0;
-}
-
 /* If P points to Lisp data, mark that as live if it isn't already
    marked.  */
 
@@ -4728,9 +4699,6 @@ mark_maybe_pointer (void *p)
   VALGRIND_MAKE_MEM_DEFINED (&p, sizeof (p));
 #endif
 
-  if (!maybe_lisp_pointer (p))
-    return;
-
   if (pdumper_object_p (p))
     {
       int type = pdumper_find_object_type (p);
@@ -4830,7 +4798,16 @@ mark_memory (void const *start, void const *end)
 
   for (pp = start; (void const *) pp < end; pp += GC_POINTER_ALIGNMENT)
     {
-      mark_maybe_pointer (*(void *const *) pp);
+      char *p = *(char *const *) pp;
+      mark_maybe_pointer (p);
+
+      /* Unmask any struct Lisp_Symbol pointer that make_lisp_symbol
+	 previously disguised by adding the address of 'lispsym'.
+	 On a host with 32-bit pointers and 64-bit Lisp_Objects,
+	 a Lisp_Object might be split into registers saved into
+	 non-adjacent words and P might be the low-order word's value.  */
+      p += (intptr_t) lispsym;
+      mark_maybe_pointer (p);
 
       verify (alignof (Lisp_Object) % GC_POINTER_ALIGNMENT == 0);
       if (alignof (Lisp_Object) == GC_POINTER_ALIGNMENT

src/xdisp.c

@@ -11575,7 +11575,9 @@ display_echo_area_1 (ptrdiff_t a1, Lisp_Object a2)
   /* Display.  */
   clear_glyph_matrix (w->desired_matrix);
   XSETWINDOW (window, w);
+  void *itdata = bidi_shelve_cache ();
   try_window (window, start, 0);
+  bidi_unshelve_cache (itdata, false);
 
   return window_height_changed_p;
 }
@@ -19748,7 +19750,7 @@ find_last_row_displaying_text (struct glyph_matrix *matrix, struct it *it,
    by changes at the start of current_buffer that occurred since W's
    current matrix was built.  Value is null if no such row exists.
 
-   BEG_UNCHANGED us the number of characters unchanged at the start of
+   BEG_UNCHANGED is the number of characters unchanged at the start of
    current_buffer.  BEG + BEG_UNCHANGED is the buffer position of the
    first changed character in current_buffer.  Characters at positions <
    BEG + BEG_UNCHANGED are at the same buffer positions as they were