Use native alignment to access Lisp object data

Instead of using __builtin_assume_aligned (P, GCALIGNMENT) to
tell GCC that P has alignment 8, use (T *) P where T is the
type of the pointed-to object, to tell GCC that P has native
alignment.  This is simpler, matches the intent better, and
should help simplify future improvements.  Some of these
changes are to pacify gcc -Wnull-dereference, since GCC is
smarter about pointers now that Emacs no longer uses
__builtin_assume_aligned; these minor changes should improve
code efficiency slightly.  On Fedora 28 x86-64 with default
optimization this patch shrinks the size of the Emacs text
segment by 0.36%.
* src/conf_post.h (__has_builtin, __builtin_assume_aligned):
Remove; no longer used.
* src/dbusbind.c (XD_OBJECT_TO_DBUS_TYPE):
Pacify -Wnull-dereference by using XCAR instead of CAR_SAFE
and XCDR instead of CDR_SAFE when this is safe.
* src/fileio.c (Fexpand_file_name):
* src/font.c (clear_font_cache):
Pacify -Wnull-dereference by removing unnecessary NILP test.
* src/keyboard.c (xevent_start): New function.
(read_char, read_key_sequence): Pacify -Wnull-dereference by
using xevent_start instead of EVENT_START.
* src/lisp.h (lisp_h_XUNTAG): Remove; XUNTAG is always a macro
now, since it can no longer be implemented as a function.
(XUNTAG): New third argument CTYPE.  All uses changed.
Cast result to CTYPE * instead of using __builtin_assume_aligned.
Simplify by using LISP_WORD_TAG.
(LISP_WORD_TAG): New macro.
(TAG_PTR): Use it.
* src/menu.c (x_popup_menu_1):
Pacify -Wnull-dereference by using XCAR instead of Fcar and
XCDR instead of Fcdr where this is safe.

18 files changed, 95 insertions, 109 deletions

diff --git a/src/alloc.c b/src/alloc.c
index f600c89ae2c..cde2e4b3407 100644
--- a/src/alloc.c
+++ b/src/alloc.c
@@ -2916,7 +2916,7 @@ DEFUN ("make-list", Fmake_list, Smake_list, 2, 2, 0,
 static struct Lisp_Vector *
 next_vector (struct Lisp_Vector *v)
 {
-  return XUNTAG (v->contents[0], Lisp_Int0);
+  return XUNTAG (v->contents[0], Lisp_Int0, struct Lisp_Vector);
 }
 
 static void
diff --git a/src/buffer.h b/src/buffer.h
index b12dad684f2..85b5631736f 100644
--- a/src/buffer.h
+++ b/src/buffer.h
@@ -912,7 +912,7 @@ INLINE struct buffer *
 XBUFFER (Lisp_Object a)
 {
   eassert (BUFFERP (a));
-  return XUNTAG (a, Lisp_Vectorlike);
+  return XUNTAG (a, Lisp_Vectorlike, struct buffer);
 }
 
 /* Most code should use these functions to set Lisp fields in struct
diff --git a/src/conf_post.h b/src/conf_post.h
index 30f3b953056..080d7b7e688 100644
--- a/src/conf_post.h
+++ b/src/conf_post.h
@@ -70,14 +70,6 @@ typedef bool bool_bf;
 # define __has_attribute_no_sanitize_undefined GNUC_PREREQ (4, 9, 0)
 #endif
 
-/* Simulate __has_builtin on compilers that lack it.  It is used only
-   on arguments like __builtin_assume_aligned that are handled in this
-   simulation.  */
-#ifndef __has_builtin
-# define __has_builtin(a) __has_builtin_##a
-# define __has_builtin___builtin_assume_aligned GNUC_PREREQ (4, 7, 0)
-#endif
-
 /* Simulate __has_feature on compilers that lack it.  It is used only
    to define ADDRESS_SANITIZER below.  */
 #ifndef __has_feature
@@ -91,11 +83,6 @@ typedef bool bool_bf;
 # define ADDRESS_SANITIZER false
 #endif
 
-/* Yield PTR, which must be aligned to ALIGNMENT.  */
-#if ! __has_builtin (__builtin_assume_aligned)
-# define __builtin_assume_aligned(ptr, ...) ((void *) (ptr))
-#endif
-
 #ifdef DARWIN_OS
 #if defined emacs && !defined CANNOT_DUMP
 #define malloc unexec_malloc
diff --git a/src/dbusbind.c b/src/dbusbind.c
index ec3707d18f3..4e0b99bea9d 100644
--- a/src/dbusbind.c
+++ b/src/dbusbind.c
@@ -207,10 +207,10 @@ xd_symbol_to_dbus_type (Lisp_Object object)
    : (STRINGP (object)) ? DBUS_TYPE_STRING                              \
    : (XD_DBUS_TYPE_P (object)) ? xd_symbol_to_dbus_type (object)        \
    : (CONSP (object))                                                   \
-   ? ((XD_DBUS_TYPE_P (CAR_SAFE (object)))                              \
-      ? ((XD_BASIC_DBUS_TYPE (xd_symbol_to_dbus_type (CAR_SAFE (object)))) \
+   ? ((XD_DBUS_TYPE_P (XCAR (object)))                                  \
+      ? ((XD_BASIC_DBUS_TYPE (xd_symbol_to_dbus_type (XCAR (object))))  \
          ? DBUS_TYPE_ARRAY                                              \
-         : xd_symbol_to_dbus_type (CAR_SAFE (object)))                  \
+         : xd_symbol_to_dbus_type (XCAR (object)))                      \
       : DBUS_TYPE_ARRAY)                                                \
    : DBUS_TYPE_INVALID)
 
@@ -396,7 +396,7 @@ xd_signature (char *signature, int dtype, int parent_type, Lisp_Object object)
       CHECK_CONS (object);
 
       /* Type symbol is optional.  */
-      if (EQ (QCarray, CAR_SAFE (elt)))
+      if (EQ (QCarray, XCAR (elt)))
         elt = XD_NEXT_VALUE (elt);
 
       /* If the array is empty, DBUS_TYPE_STRING is the default
@@ -416,10 +416,12 @@ xd_signature (char *signature, int dtype, int parent_type, Lisp_Object object)
       /* If the element type is DBUS_TYPE_SIGNATURE, and this is the
          only element, the value of this element is used as the
          array's element signature.  */
-      if ((subtype == DBUS_TYPE_SIGNATURE)
-          && STRINGP (CAR_SAFE (XD_NEXT_VALUE (elt)))
-          && NILP (CDR_SAFE (XD_NEXT_VALUE (elt))))
-        subsig = SSDATA (CAR_SAFE (XD_NEXT_VALUE (elt)));
+      if (subtype == DBUS_TYPE_SIGNATURE)
+        {
+          Lisp_Object elt1 = XD_NEXT_VALUE (elt);
+          if (CONSP (elt1) && STRINGP (XCAR (elt1)) && NILP (XCDR (elt1)))
+            subsig = SSDATA (XCAR (elt1));
+        }
 
       while (!NILP (elt))
         {
diff --git a/src/fileio.c b/src/fileio.c
index e8d966e1631..47c5fec8532 100644
--- a/src/fileio.c
+++ b/src/fileio.c
@@ -813,17 +813,14 @@ the root directory.  */)
 #endif
     }
 
-  if (!NILP (default_directory))
+  handler = Ffind_file_name_handler (default_directory, Qexpand_file_name);
+  if (!NILP (handler))
     {
-      handler = Ffind_file_name_handler (default_directory, Qexpand_file_name);
-      if (!NILP (handler))
-        {
-          handled_name = call3 (handler, Qexpand_file_name,
-                                name, default_directory);
-          if (STRINGP (handled_name))
-            return handled_name;
-          error ("Invalid handler in `file-name-handler-alist'");
-        }
+      handled_name = call3 (handler, Qexpand_file_name,
+                            name, default_directory);
+      if (STRINGP (handled_name))
+        return handled_name;
+      error ("Invalid handler in `file-name-handler-alist'");
     }
 
   {
diff --git a/src/font.c b/src/font.c
index c886c299d19..3800869c5b3 100644
--- a/src/font.c
+++ b/src/font.c
@@ -4354,10 +4354,9 @@ clear_font_cache (struct frame *f)
         Lisp_Object val, tmp, cache = driver_list->driver->get_cache (f);
 
         val = XCDR (cache);
-        while (! NILP (val)
-               && ! EQ (XCAR (XCAR (val)), driver_list->driver->type))
+        while (eassert (CONSP (val)),
+               ! EQ (XCAR (XCAR (val)), driver_list->driver->type))
           val = XCDR (val);
-        eassert (! NILP (val));
         tmp = XCDR (XCAR (val));
         if (XINT (XCAR (tmp)) == 0)
           {
diff --git a/src/font.h b/src/font.h
index 469431fee67..6ec32def4b9 100644
--- a/src/font.h
+++ b/src/font.h
@@ -494,42 +494,42 @@ INLINE struct font_spec *
 XFONT_SPEC (Lisp_Object p)
 {
   eassert (FONT_SPEC_P (p));
-  return XUNTAG (p, Lisp_Vectorlike);
+  return XUNTAG (p, Lisp_Vectorlike, struct font_spec);
 }
 
 INLINE struct font_spec *
 GC_XFONT_SPEC (Lisp_Object p)
 {
   eassert (GC_FONT_SPEC_P (p));
-  return XUNTAG (p, Lisp_Vectorlike);
+  return XUNTAG (p, Lisp_Vectorlike, struct font_spec);
 }
 
 INLINE struct font_entity *
 XFONT_ENTITY (Lisp_Object p)
 {
   eassert (FONT_ENTITY_P (p));
-  return XUNTAG (p, Lisp_Vectorlike);
+  return XUNTAG (p, Lisp_Vectorlike, struct font_entity);
 }
 
 INLINE struct font_entity *
 GC_XFONT_ENTITY (Lisp_Object p)
 {
   eassert (GC_FONT_ENTITY_P (p));
-  return XUNTAG (p, Lisp_Vectorlike);
+  return XUNTAG (p, Lisp_Vectorlike, struct font_entity);
 }
 
 INLINE struct font *
 XFONT_OBJECT (Lisp_Object p)
 {
   eassert (FONT_OBJECT_P (p));
-  return XUNTAG (p, Lisp_Vectorlike);
+  return XUNTAG (p, Lisp_Vectorlike, struct font);
 }
 
 INLINE struct font *
 GC_XFONT_OBJECT (Lisp_Object p)
 {
   eassert (GC_FONT_OBJECT_P (p));
-  return XUNTAG (p, Lisp_Vectorlike);
+  return XUNTAG (p, Lisp_Vectorlike, struct font);
 }
 
 #define XSETFONT(a, b) (XSETPSEUDOVECTOR (a, b, PVEC_FONT))
diff --git a/src/frame.h b/src/frame.h
index 2c9c4143886..1f438d3f694 100644
--- a/src/frame.h
+++ b/src/frame.h
@@ -726,7 +726,7 @@ default_pixels_per_inch_y (void)
 #define FRAME_IMAGE_CACHE(F) ((F)->terminal->image_cache)
 
 #define XFRAME(p) \
-  (eassert (FRAMEP (p)), (struct frame *) XUNTAG (p, Lisp_Vectorlike))
+  (eassert (FRAMEP (p)), XUNTAG (p, Lisp_Vectorlike, struct frame))
 #define XSETFRAME(a, b) (XSETPSEUDOVECTOR (a, b, PVEC_FRAME))
 
 /* Given a window, return its frame as a Lisp_Object.  */
diff --git a/src/keyboard.c b/src/keyboard.c
index e6b5cf79983..d498ac3feea 100644
--- a/src/keyboard.c
+++ b/src/keyboard.c
@@ -377,6 +377,15 @@ static void deliver_user_signal (int);
 static char *find_user_signal_name (int);
 static void store_user_signal_events (void);
 
+/* Like EVENT_START, but assume EVENT is an event.
+   This pacifies gcc -Wnull-dereference, which might otherwise
+   complain about earlier checks that EVENT is indeed an event.  */
+static Lisp_Object
+xevent_start (Lisp_Object event)
+{
+  return XCAR (XCDR (event));
+}
+
 /* These setters are used only in this file, so they can be private.  */
 static void
 kset_echo_string (struct kboard *kb, Lisp_Object val)
@@ -2910,8 +2919,8 @@ read_char (int commandflag, Lisp_Object map,
      so we won't do this twice, then queue it up.  */
   if (EVENT_HAS_PARAMETERS (c)
       && CONSP (XCDR (c))
-      && CONSP (EVENT_START (c))
-      && CONSP (XCDR (EVENT_START (c))))
+      && CONSP (xevent_start (c))
+      && CONSP (XCDR (xevent_start (c))))
     {
       Lisp_Object posn;
 
@@ -9397,12 +9406,12 @@ read_key_sequence (Lisp_Object *keybuf, Lisp_Object prompt,
                 }
             }
           else if (CONSP (XCDR (key))
-                   && CONSP (EVENT_START (key))
-                   && CONSP (XCDR (EVENT_START (key))))
+                   && CONSP (xevent_start (key))
+                   && CONSP (XCDR (xevent_start (key))))
             {
               Lisp_Object posn;
 
-              posn = POSN_POSN (EVENT_START (key));
+              posn = POSN_POSN (xevent_start (key));
               /* Handle menu-bar events:
                  insert the dummy prefix event `menu-bar'.  */
               if (EQ (posn, Qmenu_bar) || EQ (posn, Qtool_bar))
@@ -9414,7 +9423,7 @@ read_key_sequence (Lisp_Object *keybuf, Lisp_Object prompt,
 
                   /* Zap the position in key, so we know that we've
                      expanded it, and don't try to do so again.  */
-                  POSN_SET_POSN (EVENT_START (key), list1 (posn));
+                  POSN_SET_POSN (xevent_start (key), list1 (posn));
 
                   mock_input = t + 2;
                   goto replay_sequence;
diff --git a/src/lisp.h b/src/lisp.h
index 293cf2783c3..d4499846053 100644
--- a/src/lisp.h
+++ b/src/lisp.h
@@ -375,7 +375,7 @@ typedef EMACS_INT Lisp_Word;
 #define lisp_h_XCAR(c) XCONS (c)->u.s.car
 #define lisp_h_XCDR(c) XCONS (c)->u.s.u.cdr
 #define lisp_h_XCONS(a) \
-   (eassert (CONSP (a)), (struct Lisp_Cons *) XUNTAG (a, Lisp_Cons))
+   (eassert (CONSP (a)), XUNTAG (a, Lisp_Cons, struct Lisp_Cons))
 #define lisp_h_XHASH(a) XUINT (a)
 #ifndef GC_CHECK_CONS_LIST
 # define lisp_h_check_cons_list() ((void) 0)
@@ -388,7 +388,8 @@ typedef EMACS_INT Lisp_Word;
 # ifdef __CHKP__
 #  define lisp_h_XSYMBOL(a) \
     (eassert (SYMBOLP (a)), \
-     (struct Lisp_Symbol *) ((char *) XUNTAG (a, Lisp_Symbol) \
+     (struct Lisp_Symbol *) ((char *) XUNTAG (a, Lisp_Symbol, \
+                                              struct Lisp_Symbol) \
                              + (intptr_t) lispsym))
 # else
    /* If !__CHKP__ this is equivalent, and is a bit faster as of GCC 7.  */
@@ -398,8 +399,6 @@ typedef EMACS_INT Lisp_Word;
                              + (char *) lispsym))
 # endif
 # define lisp_h_XTYPE(a) ((enum Lisp_Type) (XLI (a) & ~VALMASK))
-# define lisp_h_XUNTAG(a, type) \
-    __builtin_assume_aligned ((char *) XLP (a) - (type), GCALIGNMENT)
 #endif
 
 /* When compiling via gcc -O0, define the key operations as macros, as
@@ -447,7 +446,6 @@ typedef EMACS_INT Lisp_Word;
 #  define XINT(a) lisp_h_XINT (a)
 #  define XSYMBOL(a) lisp_h_XSYMBOL (a)
 #  define XTYPE(a) lisp_h_XTYPE (a)
-#  define XUNTAG(a, type) lisp_h_XUNTAG (a, type)
 # endif
 #endif
 
@@ -691,20 +689,11 @@ INLINE void
   lisp_h_CHECK_TYPE (ok, predicate, x);
 }
 
-/* Extract A's pointer value, assuming A's type is TYPE.  */
-
-INLINE void *
-(XUNTAG) (Lisp_Object a, int type)
-{
-#if USE_LSB_TAG
-  return lisp_h_XUNTAG (a, type);
-#else
-  EMACS_UINT utype = type;
-  char *p = XLP (a);
-  return p - (utype << (USE_LSB_TAG ? 0 : VALBITS));
-#endif
-}
+/* Extract A's pointer value, assuming A's Lisp type is TYPE and the
+   extracted pointer's type is CTYPE *.  */
 
+#define XUNTAG(a, type, ctype) ((ctype *) \
+                                ((char *) XLP (a) - LISP_WORD_TAG (type)))
 
 /* Interned state of a symbol.  */
 
@@ -812,10 +801,9 @@ verify (!USE_LSB_TAG || alignof (struct Lisp_Symbol) % GCALIGNMENT == 0);
 #define DEFUN_ARGS_8    (Lisp_Object, Lisp_Object, Lisp_Object, Lisp_Object, \
                          Lisp_Object, Lisp_Object, Lisp_Object, Lisp_Object)
 
-/* Typedefs useful for implementing TAG_PTR.  untagged_ptr represents
-   a pointer before tagging, and Lisp_Word_tag contains a
-   possibly-shifted tag to be added to an untagged_ptr to convert it
-   to a Lisp_Word.  */
+/* untagged_ptr represents a pointer before tagging, and Lisp_Word_tag
+   contains a possibly-shifted tag to be added to an untagged_ptr to
+   convert it to a Lisp_Word.  */
 #if LISP_WORDS_ARE_POINTERS
 /* untagged_ptr is a pointer so that the compiler knows that TAG_PTR
    yields a pointer; this can help with gcc -fcheck-pointer-bounds.
@@ -830,11 +818,13 @@ typedef uintptr_t untagged_ptr;
 typedef EMACS_UINT Lisp_Word_tag;
 #endif
 
+/* A integer value tagged with TAG, and otherwise all zero.  */
+#define LISP_WORD_TAG(tag) \
+  ((Lisp_Word_tag) (tag) << (USE_LSB_TAG ? 0 : VALBITS))
+
 /* An initializer for a Lisp_Object that contains TAG along with PTR.  */
 #define TAG_PTR(tag, ptr) \
-  LISP_INITIALLY ((Lisp_Word) \
-                  ((untagged_ptr) (ptr) \
-                   + ((Lisp_Word_tag) (tag) << (USE_LSB_TAG ? 0 : VALBITS))))
+  LISP_INITIALLY ((Lisp_Word) ((untagged_ptr) (ptr) + LISP_WORD_TAG (tag)))
 
 /* LISPSYM_INITIALLY (Qfoo) is equivalent to Qfoo except it is
    designed for use as an initializer, even for a constant initializer.  */
@@ -913,7 +903,7 @@ INLINE struct Lisp_Symbol * ATTRIBUTE_NO_SANITIZE_UNDEFINED
   return lisp_h_XSYMBOL (a);
 #else
   eassert (SYMBOLP (a));
-  intptr_t i = (intptr_t) XUNTAG (a, Lisp_Symbol);
+  intptr_t i = (intptr_t) XUNTAG (a, Lisp_Symbol, struct Lisp_Symbol);
   void *p = (char *) lispsym + i;
 # ifdef __CHKP__
   /* Bypass pointer checking.  Although this could be improved it is
@@ -1159,7 +1149,7 @@ INLINE Lisp_Object
 make_lisp_ptr (void *ptr, enum Lisp_Type type)
 {
   Lisp_Object a = TAG_PTR (type, ptr);
-  eassert (XTYPE (a) == type && XUNTAG (a, type) == ptr);
+  eassert (XTYPE (a) == type && XUNTAG (a, type, char) == ptr);
   return a;
 }
 
@@ -1191,8 +1181,8 @@ INLINE bool
 /* The cast to union vectorlike_header * avoids aliasing issues.  */
 #define XSETPSEUDOVECTOR(a, b, code) \
   XSETTYPED_PSEUDOVECTOR (a, b,                                 \
-                          (((union vectorlike_header *) \
-                            XUNTAG (a, Lisp_Vectorlike))        \
+                          (XUNTAG (a, Lisp_Vectorlike,          \
+                                   union vectorlike_header)     \
                            ->size),                             \
                           code)
 #define XSETTYPED_PSEUDOVECTOR(a, b, size, code)                        \
@@ -1223,7 +1213,7 @@ INLINE bool
 INLINE void *
 XINTPTR (Lisp_Object a)
 {
-  return XUNTAG (a, Lisp_Int0);
+  return XUNTAG (a, Lisp_Int0, char);
 }
 
 INLINE Lisp_Object
@@ -1399,7 +1389,7 @@ INLINE struct Lisp_String *
 XSTRING (Lisp_Object a)
 {
   eassert (STRINGP (a));
-  return XUNTAG (a, Lisp_String);
+  return XUNTAG (a, Lisp_String, struct Lisp_String);
 }
 
 /* True if STR is a multibyte string.  */
@@ -1524,7 +1514,7 @@ INLINE struct Lisp_Vector *
 XVECTOR (Lisp_Object a)
 {
   eassert (VECTORLIKEP (a));
-  return XUNTAG (a, Lisp_Vectorlike);
+  return XUNTAG (a, Lisp_Vectorlike, struct Lisp_Vector);
 }
 
 INLINE ptrdiff_t
@@ -1584,8 +1574,9 @@ PSEUDOVECTORP (Lisp_Object a, int code)
   else
     {
       /* Converting to union vectorlike_header * avoids aliasing issues.  */
-      union vectorlike_header *h = XUNTAG (a, Lisp_Vectorlike);
-      return PSEUDOVECTOR_TYPEP (h, code);
+      return PSEUDOVECTOR_TYPEP (XUNTAG (a, Lisp_Vectorlike,
+                                         union vectorlike_header),
+                                 code);
     }
 }
 
@@ -1647,7 +1638,7 @@ INLINE struct Lisp_Bool_Vector *
 XBOOL_VECTOR (Lisp_Object a)
 {
   eassert (BOOL_VECTOR_P (a));
-  return XUNTAG (a, Lisp_Vectorlike);
+  return XUNTAG (a, Lisp_Vectorlike, struct Lisp_Bool_Vector);
 }
 
 INLINE EMACS_INT
@@ -1845,7 +1836,7 @@ INLINE struct Lisp_Char_Table *
 XCHAR_TABLE (Lisp_Object a)
 {
   eassert (CHAR_TABLE_P (a));
-  return XUNTAG (a, Lisp_Vectorlike);
+  return XUNTAG (a, Lisp_Vectorlike, struct Lisp_Char_Table);
 }
 
 struct Lisp_Sub_Char_Table
@@ -1879,7 +1870,7 @@ INLINE struct Lisp_Sub_Char_Table *
 XSUB_CHAR_TABLE (Lisp_Object a)
 {
   eassert (SUB_CHAR_TABLE_P (a));
-  return XUNTAG (a, Lisp_Vectorlike);
+  return XUNTAG (a, Lisp_Vectorlike, struct Lisp_Sub_Char_Table);
 }
 
 INLINE Lisp_Object
@@ -1957,7 +1948,7 @@ INLINE struct Lisp_Subr *
 XSUBR (Lisp_Object a)
 {
   eassert (SUBRP (a));
-  return XUNTAG (a, Lisp_Vectorlike);
+  return XUNTAG (a, Lisp_Vectorlike, struct Lisp_Subr);
 }
 
 enum char_table_specials
@@ -2210,7 +2201,7 @@ INLINE struct Lisp_Hash_Table *
 XHASH_TABLE (Lisp_Object a)
 {
   eassert (HASH_TABLE_P (a));
-  return XUNTAG (a, Lisp_Vectorlike);
+  return XUNTAG (a, Lisp_Vectorlike, struct Lisp_Hash_Table);
 }
 
 #define XSET_HASH_TABLE(VAR, PTR) \
@@ -2294,7 +2285,7 @@ INLINE struct Lisp_Misc_Any *
 XMISCANY (Lisp_Object a)
 {
   eassert (MISCP (a));
-  return XUNTAG (a, Lisp_Misc);
+  return XUNTAG (a, Lisp_Misc, struct Lisp_Misc_Any);
 }
 
 INLINE enum Lisp_Misc_Type
@@ -2470,7 +2461,7 @@ INLINE struct Lisp_Save_Value *
 XSAVE_VALUE (Lisp_Object a)
 {
   eassert (SAVE_VALUEP (a));
-  return XUNTAG (a, Lisp_Misc);
+  return XUNTAG (a, Lisp_Misc, struct Lisp_Save_Value);
 }
 
 /* Return the type of V's Nth saved value.  */
@@ -2563,7 +2554,7 @@ INLINE struct Lisp_Finalizer *
 XFINALIZER (Lisp_Object a)
 {
   eassert (FINALIZERP (a));
-  return XUNTAG (a, Lisp_Misc);
+  return XUNTAG (a, Lisp_Misc, struct Lisp_Finalizer);
 }
 
 /* A miscellaneous object, when it's on the free list.  */
@@ -2594,7 +2585,7 @@ union Lisp_Misc
 INLINE union Lisp_Misc *
 XMISC (Lisp_Object a)
 {
-  return XUNTAG (a, Lisp_Misc);
+  return XUNTAG (a, Lisp_Misc, union Lisp_Misc);
 }
 
 INLINE bool
@@ -2607,7 +2598,7 @@ INLINE struct Lisp_Marker *
 XMARKER (Lisp_Object a)
 {
   eassert (MARKERP (a));
-  return XUNTAG (a, Lisp_Misc);
+  return XUNTAG (a, Lisp_Misc, struct Lisp_Marker);
 }
 
 INLINE bool
@@ -2620,7 +2611,7 @@ INLINE struct Lisp_Overlay *
 XOVERLAY (Lisp_Object a)
 {
   eassert (OVERLAYP (a));
-  return XUNTAG (a, Lisp_Misc);
+  return XUNTAG (a, Lisp_Misc, struct Lisp_Overlay);
 }
 
 #ifdef HAVE_MODULES
@@ -2634,7 +2625,7 @@ INLINE struct Lisp_User_Ptr *
 XUSER_PTR (Lisp_Object a)
 {
   eassert (USER_PTRP (a));
-  return XUNTAG (a, Lisp_Misc);
+  return XUNTAG (a, Lisp_Misc, struct Lisp_User_Ptr);
 }
 #endif
 
@@ -2778,7 +2769,7 @@ INLINE struct Lisp_Float *
 XFLOAT (Lisp_Object a)
 {
   eassert (FLOATP (a));
-  return XUNTAG (a, Lisp_Float);
+  return XUNTAG (a, Lisp_Float, struct Lisp_Float);
 }
 
 INLINE double
@@ -4055,7 +4046,7 @@ INLINE struct Lisp_Module_Function *
 XMODULE_FUNCTION (Lisp_Object o)
 {
   eassert (MODULE_FUNCTIONP (o));
-  return XUNTAG (o, Lisp_Vectorlike);
+  return XUNTAG (o, Lisp_Vectorlike, struct Lisp_Module_Function);
 }
 
 #ifdef HAVE_MODULES
diff --git a/src/menu.c b/src/menu.c
index 93e793a5d91..e7d4d782fe8 100644
--- a/src/menu.c
+++ b/src/menu.c
@@ -1152,7 +1152,7 @@ x_popup_menu_1 (Lisp_Object position, Lisp_Object menu)
         else
           {
             menuflags |= MENU_FOR_CLICK;
-            tem = Fcar (Fcdr (position));  /* EVENT_START (position) */
+            tem = Fcar (XCDR (position));    /* EVENT_START (position) */
             window = Fcar (tem);             /* POSN_WINDOW (tem) */
             tem2 = Fcar (Fcdr (tem));        /* POSN_POSN (tem) */
             /* The MENU_KBD_NAVIGATION field is set when the menu
@@ -1168,7 +1168,7 @@ x_popup_menu_1 (Lisp_Object position, Lisp_Object menu)
                event.  */
             if (!EQ (POSN_POSN (last_nonmenu_event),
                      POSN_POSN (position))
-                && CONSP (tem2) && EQ (Fcar (tem2), Qmenu_bar))
+                && CONSP (tem2) && EQ (XCAR (tem2), Qmenu_bar))
               menuflags |= MENU_KBD_NAVIGATION;
             tem = Fcar (Fcdr (Fcdr (tem))); /* POSN_WINDOW_POSN (tem) */
             x = Fcar (tem);
diff --git a/src/process.h b/src/process.h
index 6464a8cc61a..42cc66ec560 100644
--- a/src/process.h
+++ b/src/process.h
@@ -220,7 +220,7 @@ INLINE struct Lisp_Process *
 XPROCESS (Lisp_Object a)
 {
   eassert (PROCESSP (a));
-  return XUNTAG (a, Lisp_Vectorlike);
+  return XUNTAG (a, Lisp_Vectorlike, struct Lisp_Process);
 }
 
 /* Every field in the preceding structure except for the first two
diff --git a/src/termhooks.h b/src/termhooks.h
index 1b2c95e8248..d8c5edc948e 100644
--- a/src/termhooks.h
+++ b/src/termhooks.h
@@ -669,7 +669,7 @@ INLINE struct terminal *
 XTERMINAL (Lisp_Object a)
 {
   eassert (TERMINALP (a));
-  return XUNTAG (a, Lisp_Vectorlike);
+  return XUNTAG (a, Lisp_Vectorlike, struct terminal);
 }
 
 /* Most code should use these functions to set Lisp fields in struct
diff --git a/src/thread.h b/src/thread.h
index 5ab5e90c70d..2c8914e1b28 100644
--- a/src/thread.h
+++ b/src/thread.h
@@ -208,7 +208,7 @@ INLINE struct thread_state *
 XTHREAD (Lisp_Object a)
 {
   eassert (THREADP (a));
-  return XUNTAG (a, Lisp_Vectorlike);
+  return XUNTAG (a, Lisp_Vectorlike, struct thread_state);
 }
 
 /* A mutex in lisp is represented by a system condition variable.
@@ -255,7 +255,7 @@ INLINE struct Lisp_Mutex *
 XMUTEX (Lisp_Object a)
 {
   eassert (MUTEXP (a));
-  return XUNTAG (a, Lisp_Vectorlike);
+  return XUNTAG (a, Lisp_Vectorlike, struct Lisp_Mutex);
 }
 
 /* A condition variable as a lisp object.  */
@@ -289,7 +289,7 @@ INLINE struct Lisp_CondVar *
 XCONDVAR (Lisp_Object a)
 {
   eassert (CONDVARP (a));
-  return XUNTAG (a, Lisp_Vectorlike);
+  return XUNTAG (a, Lisp_Vectorlike, struct Lisp_CondVar);
 }
 
 extern struct thread_state *current_thread;
diff --git a/src/w32fns.c b/src/w32fns.c
index 5d1c3c84c67..2cb715a356d 100644
--- a/src/w32fns.c
+++ b/src/w32fns.c
@@ -8542,7 +8542,7 @@ DEFUN ("w32-unregister-hot-key", Fw32_unregister_hot_key,
       eassert (CONSP (item));
       /* Pass the tail of the list as a pointer to a Lisp_Cons cell,
          so that it works in a --with-wide-int build as well.  */
-      lparam = (LPARAM) XUNTAG (item, Lisp_Cons);
+      lparam = (LPARAM) XUNTAG (item, Lisp_Cons, struct Lisp_Cons);
 
       /* Notify input thread about hot-key definition being removed, so
          that it takes effect without needing focus switch.  */
diff --git a/src/w32menu.c b/src/w32menu.c
index 30ad54db26d..ece5836498f 100644
--- a/src/w32menu.c
+++ b/src/w32menu.c
@@ -1407,7 +1407,8 @@ add_menu_item (HMENU menu, widget_value *wv, HMENU item)
                  Windows alike.  MSVC headers get it right; hopefully,
                  MinGW headers will, too.  */
               eassert (STRINGP (wv->help));
-              info.dwItemData = (ULONG_PTR) XUNTAG (wv->help, Lisp_String);
+              info.dwItemData = (ULONG_PTR) XUNTAG (wv->help, Lisp_String,
+                                                    struct Lisp_String);
             }
           if (wv->button_type == BUTTON_TYPE_RADIO)
             {
diff --git a/src/window.h b/src/window.h
index 91ef7d90272..013083eb9a8 100644
--- a/src/window.h
+++ b/src/window.h
@@ -418,7 +418,7 @@ INLINE struct window *
 XWINDOW (Lisp_Object a)
 {
   eassert (WINDOWP (a));
-  return XUNTAG (a, Lisp_Vectorlike);
+  return XUNTAG (a, Lisp_Vectorlike, struct window);
 }
 
 /* Most code should use these functions to set Lisp fields in struct
diff --git a/src/xwidget.h b/src/xwidget.h
index 93f4cfb7949..89fc7ff4586 100644
--- a/src/xwidget.h
+++ b/src/xwidget.h
@@ -94,7 +94,7 @@ struct xwidget_view
 /* Test for xwidget pseudovector.  */
 #define XWIDGETP(x) PSEUDOVECTORP (x, PVEC_XWIDGET)
 #define XXWIDGET(a) (eassert (XWIDGETP (a)), \
-                     (struct xwidget *) XUNTAG (a, Lisp_Vectorlike))
+                     XUNTAG (a, Lisp_Vectorlike, struct xwidget))
 
 #define CHECK_XWIDGET(x) \
   CHECK_TYPE (XWIDGETP (x), Qxwidgetp, x)
@@ -102,7 +102,7 @@ struct xwidget_view
 /* Test for xwidget_view pseudovector.  */
 #define XWIDGET_VIEW_P(x) PSEUDOVECTORP (x, PVEC_XWIDGET_VIEW)
 #define XXWIDGET_VIEW(a) (eassert (XWIDGET_VIEW_P (a)), \
-                          (struct xwidget_view *) XUNTAG (a, Lisp_Vectorlike))
+                          XUNTAG (a, Lisp_Vectorlike, struct xwidget_view))
 
 #define CHECK_XWIDGET_VIEW(x) \
   CHECK_TYPE (XWIDGET_VIEW_P (x), Qxwidget_view_p, x)