Mark _Noreturn error functions as cold

On my platform this made ‘make compile-always’ 1.3% faster.
Suggested by Alex Gramiak in:
https://lists.gnu.org/r/emacs-devel/2019-04/msg00684.html
* configure.ac (nw): Don’t use -Wsuggest-attribute=cold.
* lib-src/make-docfile.c (write_globals):
Mark noreturn functions as cold.
* src/callproc.c (exec_failed):
* src/data.c (wrong_length_argument, wrong_type_argument):
* src/emacs-module.c (module_abort):
* src/emacs.c (terminate_due_to_signal):
* src/eval.c (unwind_to_catch):
* src/image.c (my_png_error, my_error_exit):
* src/json.c (json_out_of_memory, json_parse_error):
* src/keyboard.c (quit_throw_to_read_char, user_error):
* src/lisp.h (die, wrong_type_argument, wrong_choice)
(args_out_of_range, args_out_of_range_3, circular_list)
(buffer_overflow, memory_full, buffer_memory_full)
(string_overflow, xsignal, xsignal0, xsignal1, xsignal2)
(xsignal3, signal_error, overflow_error, error, verror)
(nsberror, report_file_errno, report_file_error)
(report_file_notify_error, terminate_due_to_signal)
(emacs_abort, fatal):
* src/lread.c (load_error_old_style_backquotes)
(end_of_file_error, invalid_syntax):
* src/pdumper.c (error_unsupported_dump_object):
* src/puresize.h (pure_write_error):
* src/search.c (matcher_overflow):
* src/sound.c (sound_perror, alsa_sound_perror):
* src/sysdep.c (handle_arith_signal):
* src/systime.h (time_overflow):
* src/term.c (maybe_fatal, vfatal):
* src/textprop.c (text_read_only):
* src/timefns.c (invalid_time_zone_specification)
(time_error, invalid_hz):
* src/xterm.c (x_connection_closed):
Use AVOID instead of _Noreturn void, so that it’s marked cold.
* src/conf_post.h (__has_attribute_cold) [!__has_attribute]:
New macro.
(ATTRIBUTE_COLD): New macro.
* src/frame.h (WINDOW_SYSTEM_RETURN): Add ATTRIBUTE_COLD.
* src/lisp.h (AVOID): New macro.
* src/xterm.c: Omit unnecessary static decls, so that we needn’t
worry about which functions should be marked cold.
(x_io_error_quitter): Mark as cold.

22 files changed, 70 insertions, 98 deletions

diff --git a/src/callproc.c b/src/callproc.c
index 2cdf84d9a80..98c67312b49 100644
--- a/src/callproc.c
+++ b/src/callproc.c
@@ -1135,7 +1135,7 @@ add_env (char **env, char **new_env, char *string)
    mess up the allocator's data structures in the parent.
    Report the error and exit the child.  */
 
-static _Noreturn void
+static AVOID
 exec_failed (char const *name, int err)
 {
   /* Avoid deadlock if the child's perror writes to a full pipe; the
diff --git a/src/conf_post.h b/src/conf_post.h
index f8254cfa9df..6ea2c7b664b 100644
--- a/src/conf_post.h
+++ b/src/conf_post.h
@@ -73,6 +73,7 @@ typedef bool bool_bf;
 # define __has_attribute(a) __has_attribute_##a
 # define __has_attribute_alloc_size GNUC_PREREQ (4, 3, 0)
 # define __has_attribute_cleanup GNUC_PREREQ (3, 4, 0)
+# define __has_attribute_cold GNUC_PREREQ (4, 3, 0)
 # define __has_attribute_externally_visible GNUC_PREREQ (4, 1, 0)
 # define __has_attribute_no_address_safety_analysis false
 # define __has_attribute_no_sanitize_address GNUC_PREREQ (4, 8, 0)
@@ -223,6 +224,12 @@ extern void _DebPrint (const char *fmt, ...);
 extern char *emacs_getenv_TZ (void);
 extern int emacs_setenv_TZ (char const *);
 
+#if __has_attribute (cold)
+# define ATTRIBUTE_COLD __attribute__ ((cold))
+#else
+# define ATTRIBUTE_COLD
+#endif
+
 #if __GNUC__ >= 3  /* On GCC 3.0 we might get a warning.  */
 #define NO_INLINE __attribute__((noinline))
 #else
diff --git a/src/data.c b/src/data.c
index 11cd598ed85..1b2431011e9 100644
--- a/src/data.c
+++ b/src/data.c
@@ -130,7 +130,7 @@ set_blv_valcell (struct Lisp_Buffer_Local_Value *blv, Lisp_Object val)
   blv->valcell = val;
 }
 
-static _Noreturn void
+static AVOID
 wrong_length_argument (Lisp_Object a1, Lisp_Object a2, Lisp_Object a3)
 {
   Lisp_Object size1 = make_fixnum (bool_vector_size (a1));
@@ -142,7 +142,7 @@ wrong_length_argument (Lisp_Object a1, Lisp_Object a2, Lisp_Object a3)
               make_fixnum (bool_vector_size (a3)));
 }
 
-_Noreturn void
+AVOID
 wrong_type_argument (register Lisp_Object predicate, register Lisp_Object value)
 {
   /* If VALUE is not even a valid Lisp object, we'd want to abort here
diff --git a/src/emacs-module.c b/src/emacs-module.c
index 47ca3368c0f..09a768e18ed 100644
--- a/src/emacs-module.c
+++ b/src/emacs-module.c
@@ -147,8 +147,7 @@ static enum emacs_funcall_exit module_non_local_exit_check (emacs_env *);
 static void module_assert_thread (void);
 static void module_assert_runtime (struct emacs_runtime *);
 static void module_assert_env (emacs_env *);
-static _Noreturn void module_abort (const char *format, ...)
-  ATTRIBUTE_FORMAT_PRINTF(1, 2);
+static AVOID module_abort (const char *, ...) ATTRIBUTE_FORMAT_PRINTF (1, 2);
 static emacs_env *initialize_environment (emacs_env *,
                                           struct emacs_env_private *);
 static void finalize_environment (emacs_env *);
@@ -1163,8 +1162,7 @@ init_module_assertions (bool enable)
   initialize_storage (&global_storage);
 }
 
-static _Noreturn void
-ATTRIBUTE_FORMAT_PRINTF(1, 2)
+static AVOID ATTRIBUTE_FORMAT_PRINTF (1, 2)
 module_abort (const char *format, ...)
 {
   fputs ("Emacs module assertion: ", stderr);
diff --git a/src/emacs.c b/src/emacs.c
index 6ed4b0ed87a..5eba88c74ff 100644
--- a/src/emacs.c
+++ b/src/emacs.c
@@ -370,7 +370,7 @@ using_utf8 (void)
 
 /* Report a fatal error due to signal SIG, output a backtrace of at
    most BACKTRACE_LIMIT lines, and exit.  */
-_Noreturn void
+AVOID
 terminate_due_to_signal (int sig, int backtrace_limit)
 {
   signal (sig, SIG_DFL);
diff --git a/src/eval.c b/src/eval.c
index fa7b2d06031..c2e996a9474 100644
--- a/src/eval.c
+++ b/src/eval.c
@@ -1133,7 +1133,7 @@ internal_catch (Lisp_Object tag,
 
    This is used for correct unwinding in Fthrow and Fsignal.  */
 
-static _Noreturn void
+static AVOID
 unwind_to_catch (struct handler *catch, Lisp_Object value)
 {
   bool last_time;
diff --git a/src/frame.h b/src/frame.h
index ec8f61465f2..e2e8eaab9bb 100644
--- a/src/frame.h
+++ b/src/frame.h
@@ -1262,7 +1262,7 @@ extern int frame_default_tool_bar_height;
 #ifdef HAVE_WINDOW_SYSTEM
 # define WINDOW_SYSTEM_RETURN
 #else
-# define WINDOW_SYSTEM_RETURN _Noreturn
+# define WINDOW_SYSTEM_RETURN _Noreturn ATTRIBUTE_COLD
 #endif
 
 extern WINDOW_SYSTEM_RETURN struct frame *
diff --git a/src/image.c b/src/image.c
index c1a23edefce..8e3a9a4930a 100644
--- a/src/image.c
+++ b/src/image.c
@@ -6079,7 +6079,7 @@ init_png_functions (void)
 /* Error and warning handlers installed when the PNG library
    is initialized.  */
 
-static _Noreturn void
+static AVOID
 my_png_error (png_struct *png_ptr, const char *msg)
 {
   eassert (png_ptr != NULL);
@@ -6718,7 +6718,7 @@ struct my_jpeg_error_mgr
 };
 
 
-static _Noreturn void
+static AVOID
 my_error_exit (j_common_ptr cinfo)
 {
   struct my_jpeg_error_mgr *mgr = (struct my_jpeg_error_mgr *) cinfo->err;
diff --git a/src/json.c b/src/json.c
index 74e0534065f..5917212899e 100644
--- a/src/json.c
+++ b/src/json.c
@@ -255,7 +255,7 @@ json_encode (Lisp_Object string)
   return code_convert_string (string, Qutf_8_unix, Qt, true, true, true);
 }
 
-static _Noreturn void
+static AVOID
 json_out_of_memory (void)
 {
   xsignal0 (Qjson_out_of_memory);
@@ -263,7 +263,7 @@ json_out_of_memory (void)
 
 /* Signal a Lisp error corresponding to the JSON ERROR.  */
 
-static _Noreturn void
+static AVOID
 json_parse_error (const json_error_t *error)
 {
   Lisp_Object symbol;
diff --git a/src/keyboard.c b/src/keyboard.c
index 8fb6db987b5..dff8f6b2fc9 100644
--- a/src/keyboard.c
+++ b/src/keyboard.c
@@ -364,7 +364,7 @@ static void restore_getcjmp (void *);
 static Lisp_Object apply_modifiers (int, Lisp_Object);
 static void restore_kboard_configuration (int);
 static void handle_interrupt (bool);
-static _Noreturn void quit_throw_to_read_char (bool);
+static AVOID quit_throw_to_read_char (bool);
 static void timer_start_idle (void);
 static void timer_stop_idle (void);
 static void timer_resume_idle (void);
@@ -1131,13 +1131,12 @@ This also exits all active minibuffers.  */
   Fthrow (Qtop_level, Qnil);
 }
 
-static _Noreturn void
+static AVOID
 user_error (const char *msg)
 {
   xsignal1 (Quser_error, build_string (msg));
 }
 
-/* _Noreturn will be added to prototype by make-docfile.  */
 DEFUN ("exit-recursive-edit", Fexit_recursive_edit, Sexit_recursive_edit, 0, 0, "",
        doc: /* Exit from the innermost recursive edit or minibuffer.  */
        attributes: noreturn)
@@ -1149,7 +1148,6 @@ DEFUN ("exit-recursive-edit", Fexit_recursive_edit, Sexit_recursive_edit, 0, 0,
   user_error ("No recursive edit is in progress");
 }
 
-/* _Noreturn will be added to prototype by make-docfile.  */
 DEFUN ("abort-recursive-edit", Fabort_recursive_edit, Sabort_recursive_edit, 0, 0, "",
        doc: /* Abort the command that requested this recursive edit or minibuffer input.  */
        attributes: noreturn)
diff --git a/src/lisp.h b/src/lisp.h
index 2915944ffec..25d0a3d6ac1 100644
--- a/src/lisp.h
+++ b/src/lisp.h
@@ -166,6 +166,9 @@ typedef EMACS_UINT uprintmax_t;
 # define pD "t"
 #endif
 
+/* Convenience macro for rarely-used functions that do not return.  */
+#define AVOID _Noreturn ATTRIBUTE_COLD void
+
 /* Extra internal type checking?  */
 
 /* Define Emacs versions of <assert.h>'s 'assert (COND)' and <verify.h>'s
@@ -196,7 +199,7 @@ typedef EMACS_UINT uprintmax_t;
 # define eassume(cond) assume (cond)
 #else /* ENABLE_CHECKING */
 
-extern _Noreturn void die (const char *, const char *, int);
+extern AVOID die (const char *, const char *, int);
 
 extern bool suppress_checking EXTERNALLY_VISIBLE;
 
@@ -621,7 +624,7 @@ extern Lisp_Object char_table_ref (Lisp_Object, int);
 extern void char_table_set (Lisp_Object, int, Lisp_Object);
 
 /* Defined in data.c.  */
-extern _Noreturn void wrong_type_argument (Lisp_Object, Lisp_Object);
+extern AVOID wrong_type_argument (Lisp_Object, Lisp_Object);
 
 
 /* Defined in emacs.c.  */
@@ -3528,7 +3531,7 @@ modiff_to_integer (modiff_count a)
 }
 
 /* Defined in data.c.  */
-extern _Noreturn void wrong_choice (Lisp_Object, Lisp_Object);
+extern AVOID wrong_choice (Lisp_Object, Lisp_Object);
 extern void notify_variable_watchers (Lisp_Object, Lisp_Object,
                                       Lisp_Object, Lisp_Object);
 extern Lisp_Object indirect_function (Lisp_Object);
@@ -3555,10 +3558,9 @@ extern intmax_t cons_to_signed (Lisp_Object, intmax_t, intmax_t);
 extern uintmax_t cons_to_unsigned (Lisp_Object, uintmax_t);
 
 extern struct Lisp_Symbol *indirect_variable (struct Lisp_Symbol *);
-extern _Noreturn void args_out_of_range (Lisp_Object, Lisp_Object);
-extern _Noreturn void args_out_of_range_3 (Lisp_Object, Lisp_Object,
-                                           Lisp_Object);
-extern _Noreturn void circular_list (Lisp_Object);
+extern AVOID args_out_of_range (Lisp_Object, Lisp_Object);
+extern AVOID args_out_of_range_3 (Lisp_Object, Lisp_Object, Lisp_Object);
+extern AVOID circular_list (Lisp_Object);
 extern Lisp_Object do_symval_forwarding (lispfwd);
 enum Set_Internal_Bind {
   SET_INTERNAL_SET,
@@ -3666,7 +3668,7 @@ extern void syms_of_json (void);
 
 /* Defined in insdel.c.  */
 extern void move_gap_both (ptrdiff_t, ptrdiff_t);
-extern _Noreturn void buffer_overflow (void);
+extern AVOID buffer_overflow (void);
 extern void make_gap (ptrdiff_t);
 extern void make_gap_1 (struct buffer *, ptrdiff_t);
 extern ptrdiff_t copy_text (const unsigned char *, unsigned char *,
@@ -3766,8 +3768,8 @@ extern void *my_heap_start (void);
 extern void check_pure_size (void);
 extern void allocate_string_data (struct Lisp_String *, EMACS_INT, EMACS_INT);
 extern void malloc_warning (const char *);
-extern _Noreturn void memory_full (size_t);
-extern _Noreturn void buffer_memory_full (ptrdiff_t);
+extern AVOID memory_full (size_t);
+extern AVOID buffer_memory_full (ptrdiff_t);
 extern bool survives_gc_p (Lisp_Object);
 extern void mark_object (Lisp_Object);
 #if defined REL_ALLOC && !defined SYSTEM_MALLOC && !defined HYBRID_MALLOC
@@ -3848,7 +3850,7 @@ list4i (EMACS_INT x, EMACS_INT y, EMACS_INT w, EMACS_INT h)
 
 extern Lisp_Object make_uninit_bool_vector (EMACS_INT);
 extern Lisp_Object bool_vector_fill (Lisp_Object, Lisp_Object);
-extern _Noreturn void string_overflow (void);
+extern AVOID string_overflow (void);
 extern Lisp_Object make_string (const char *, ptrdiff_t);
 extern Lisp_Object make_formatted_string (char *, const char *, ...)
   ATTRIBUTE_FORMAT_PRINTF (2, 3);
@@ -4095,18 +4097,17 @@ extern Lisp_Object run_hook_with_args (ptrdiff_t nargs, Lisp_Object *args,
                                        Lisp_Object (*funcall)
                                        (ptrdiff_t nargs, Lisp_Object *args));
 extern Lisp_Object quit (void);
-INLINE _Noreturn void
+INLINE AVOID
 xsignal (Lisp_Object error_symbol, Lisp_Object data)
 {
   Fsignal (error_symbol, data);
 }
-extern _Noreturn void xsignal0 (Lisp_Object);
-extern _Noreturn void xsignal1 (Lisp_Object, Lisp_Object);
-extern _Noreturn void xsignal2 (Lisp_Object, Lisp_Object, Lisp_Object);
-extern _Noreturn void xsignal3 (Lisp_Object, Lisp_Object, Lisp_Object,
-                                Lisp_Object);
-extern _Noreturn void signal_error (const char *, Lisp_Object);
-extern _Noreturn void overflow_error (void);
+extern AVOID xsignal0 (Lisp_Object);
+extern AVOID xsignal1 (Lisp_Object, Lisp_Object);
+extern AVOID xsignal2 (Lisp_Object, Lisp_Object, Lisp_Object);
+extern AVOID xsignal3 (Lisp_Object, Lisp_Object, Lisp_Object, Lisp_Object);
+extern AVOID signal_error (const char *, Lisp_Object);
+extern AVOID overflow_error (void);
 extern bool FUNCTIONP (Lisp_Object);
 extern Lisp_Object funcall_subr (struct Lisp_Subr *subr, ptrdiff_t numargs, Lisp_Object *arg_vector);
 extern Lisp_Object eval_sub (Lisp_Object form);
@@ -4145,8 +4146,8 @@ extern void set_unwind_protect_ptr (ptrdiff_t, void (*) (void *), void *);
 extern Lisp_Object unbind_to (ptrdiff_t, Lisp_Object);
 extern void rebind_for_thread_switch (void);
 extern void unbind_for_thread_switch (struct thread_state *);
-extern _Noreturn void error (const char *, ...) ATTRIBUTE_FORMAT_PRINTF (1, 2);
-extern _Noreturn void verror (const char *, va_list)
+extern AVOID error (const char *, ...) ATTRIBUTE_FORMAT_PRINTF (1, 2);
+extern AVOID verror (const char *, va_list)
   ATTRIBUTE_FORMAT_PRINTF (1, 0);
 extern Lisp_Object vformat_string (const char *, va_list)
   ATTRIBUTE_FORMAT_PRINTF (1, 0);
@@ -4243,7 +4244,7 @@ extern void syms_of_editfns (void);
 /* Defined in buffer.c.  */
 extern bool mouse_face_overlay_overlaps (Lisp_Object);
 extern Lisp_Object disable_line_numbers_overlay_at_eob (void);
-extern _Noreturn void nsberror (Lisp_Object);
+extern AVOID nsberror (Lisp_Object);
 extern void adjust_overlays_for_insert (ptrdiff_t, ptrdiff_t);
 extern void adjust_overlays_for_delete (ptrdiff_t, ptrdiff_t);
 extern void fix_start_end_in_overlays (ptrdiff_t, ptrdiff_t);
@@ -4286,9 +4287,9 @@ extern void close_file_unwind (int);
 extern void fclose_unwind (void *);
 extern void restore_point_unwind (Lisp_Object);
 extern Lisp_Object get_file_errno_data (const char *, Lisp_Object, int);
-extern _Noreturn void report_file_errno (const char *, Lisp_Object, int);
-extern _Noreturn void report_file_error (const char *, Lisp_Object);
-extern _Noreturn void report_file_notify_error (const char *, Lisp_Object);
+extern AVOID report_file_errno (const char *, Lisp_Object, int);
+extern AVOID report_file_error (const char *, Lisp_Object);
+extern AVOID report_file_notify_error (const char *, Lisp_Object);
 extern bool internal_delete_file (Lisp_Object);
 extern Lisp_Object emacs_readlinkat (int, const char *);
 extern bool file_directory_p (Lisp_Object);
@@ -4409,7 +4410,7 @@ extern bool display_arg;
 #endif
 extern Lisp_Object decode_env_path (const char *, const char *, bool);
 extern Lisp_Object empty_unibyte_string, empty_multibyte_string;
-extern _Noreturn void terminate_due_to_signal (int, int);
+extern AVOID terminate_due_to_signal (int, int);
 #ifdef WINDOWSNT
 extern Lisp_Object Vlibrary_cache;
 #endif
@@ -4574,7 +4575,7 @@ extern EMACS_INT get_random (void);
 extern void seed_random (void *, ptrdiff_t);
 extern void init_random (void);
 extern void emacs_backtrace (int);
-extern _Noreturn void emacs_abort (void) NO_INLINE;
+extern AVOID emacs_abort (void) NO_INLINE;
 extern int emacs_open (const char *, int, int);
 extern int emacs_pipe (int[2]);
 extern int emacs_close (int);
@@ -4615,8 +4616,7 @@ extern Lisp_Object directory_files_internal (Lisp_Object, Lisp_Object,
 /* Defined in term.c.  */
 extern int *char_ins_del_vector;
 extern void syms_of_term (void);
-extern _Noreturn void fatal (const char *msgid, ...)
-  ATTRIBUTE_FORMAT_PRINTF (1, 2);
+extern AVOID fatal (const char *msgid, ...) ATTRIBUTE_FORMAT_PRINTF (1, 2);
 
 /* Defined in terminal.c.  */
 extern void syms_of_terminal (void);
diff --git a/src/lread.c b/src/lread.c
index 5f33fcd6957..8cb4b63cc3a 100644
--- a/src/lread.c
+++ b/src/lread.c
@@ -1019,7 +1019,7 @@ load_error_handler (Lisp_Object data)
   return Qnil;
 }
 
-static _Noreturn void
+static AVOID
 load_error_old_style_backquotes (void)
 {
   if (NILP (Vload_file_name))
@@ -1874,7 +1874,7 @@ readevalloop_1 (int old)
 /* Signal an `end-of-file' error, if possible with file name
    information.  */
 
-static _Noreturn void
+static AVOID
 end_of_file_error (void)
 {
   if (STRINGP (Vload_file_name))
@@ -2297,7 +2297,7 @@ read_internal_start (Lisp_Object stream, Lisp_Object start, Lisp_Object end)
 /* Signal Qinvalid_read_syntax error.
    S is error string of length N (if > 0)  */
 
-static _Noreturn void
+static AVOID
 invalid_syntax (const char *s)
 {
   xsignal1 (Qinvalid_read_syntax, build_string (s));
diff --git a/src/pdumper.c b/src/pdumper.c
index 600c5b3ca3d..2cc9af7f56c 100644
--- a/src/pdumper.c
+++ b/src/pdumper.c
@@ -680,8 +680,7 @@ static void dump_remember_cold_op (struct dump_context *ctx,
                                    enum cold_op op,
                                    Lisp_Object arg);
 
-_Noreturn
-static void
+static AVOID
 error_unsupported_dump_object (struct dump_context *ctx,
                                Lisp_Object object,
                                const char *msg)
diff --git a/src/puresize.h b/src/puresize.h
index f120a4b3307..f5fad8b42b6 100644
--- a/src/puresize.h
+++ b/src/puresize.h
@@ -77,7 +77,7 @@ INLINE_HEADER_BEGIN
 #define PURESIZE  (BASE_PURESIZE * PURESIZE_RATIO * PURESIZE_CHECKING_RATIO)
 #endif
 
-extern _Noreturn void pure_write_error (Lisp_Object);
+extern AVOID pure_write_error (Lisp_Object);
 
 extern EMACS_INT pure[];
 
diff --git a/src/search.c b/src/search.c
index a450e920b03..7a6e680685a 100644
--- a/src/search.c
+++ b/src/search.c
@@ -73,7 +73,7 @@ static EMACS_INT search_buffer (Lisp_Object, ptrdiff_t, ptrdiff_t,
 
 Lisp_Object re_match_object;
 
-static _Noreturn void
+static AVOID
 matcher_overflow (void)
 {
   error ("Stack overflow in regexp matcher");
diff --git a/src/sound.c b/src/sound.c
index 2b8715010e7..4ba826e82c4 100644
--- a/src/sound.c
+++ b/src/sound.c
@@ -297,7 +297,7 @@ static int do_play_sound (const char *, unsigned long);
 #ifndef WINDOWSNT
 /* Like perror, but signals an error.  */
 
-static _Noreturn void
+static AVOID
 sound_perror (const char *msg)
 {
   int saved_errno = errno;
@@ -874,7 +874,7 @@ vox_write (struct sound_device *sd, const char *buffer, ptrdiff_t nbytes)
 #define DEFAULT_ALSA_SOUND_DEVICE "default"
 #endif
 
-static _Noreturn void
+static AVOID
 alsa_sound_perror (const char *msg, int err)
 {
   error ("%s: %s", msg, snd_strerror (err));
diff --git a/src/sysdep.c b/src/sysdep.c
index 57ea8220cac..bc88e70dcb4 100644
--- a/src/sysdep.c
+++ b/src/sysdep.c
@@ -1805,7 +1805,7 @@ deliver_fatal_thread_signal (int sig)
   deliver_thread_signal (sig, handle_fatal_signal);
 }
 
-static _Noreturn void
+static AVOID
 handle_arith_signal (int sig)
 {
   pthread_sigmask (SIG_SETMASK, &empty_mask, 0);
diff --git a/src/systime.h b/src/systime.h
index 9080cd2bba1..89af0c5e3df 100644
--- a/src/systime.h
+++ b/src/systime.h
@@ -92,7 +92,7 @@ extern Lisp_Object make_lisp_time (struct timespec);
 extern bool list4_to_timespec (Lisp_Object, Lisp_Object, Lisp_Object,
                                Lisp_Object, struct timespec *);
 extern struct timespec lisp_time_argument (Lisp_Object);
-extern _Noreturn void time_overflow (void);
+extern AVOID time_overflow (void);
 extern void init_timefns (void);
 extern void syms_of_timefns (void);
 
diff --git a/src/term.c b/src/term.c
index a492276c888..2de0a0e6649 100644
--- a/src/term.c
+++ b/src/term.c
@@ -73,11 +73,10 @@ static void clear_tty_hooks (struct terminal *terminal);
 static void set_tty_hooks (struct terminal *terminal);
 static void dissociate_if_controlling_tty (int fd);
 static void delete_tty (struct terminal *);
-static _Noreturn void maybe_fatal (bool, struct terminal *,
-                                   const char *, const char *, ...)
+static AVOID maybe_fatal (bool, struct terminal *, const char *, const char *,
+                          ...)
   ATTRIBUTE_FORMAT_PRINTF (3, 5) ATTRIBUTE_FORMAT_PRINTF (4, 5);
-static _Noreturn void vfatal (const char *str, va_list ap)
-  ATTRIBUTE_FORMAT_PRINTF (1, 0);
+static AVOID vfatal (const char *, va_list) ATTRIBUTE_FORMAT_PRINTF (1, 0);
 
 
 #define OUTPUT(tty, a)                                          \
diff --git a/src/textprop.c b/src/textprop.c
index bb063d3eaaa..ae42c44185f 100644
--- a/src/textprop.c
+++ b/src/textprop.c
@@ -65,7 +65,7 @@ static Lisp_Object interval_insert_in_front_hooks;
 /* Signal a `text-read-only' error.  This function makes it easier
    to capture that error in GDB by putting a breakpoint on it.  */
 
-static _Noreturn void
+static AVOID
 text_read_only (Lisp_Object propval)
 {
   if (STRINGP (propval))
diff --git a/src/timefns.c b/src/timefns.c
index 514fa24f8b9..cb953d1b4ce 100644
--- a/src/timefns.c
+++ b/src/timefns.c
@@ -172,7 +172,7 @@ emacs_localtime_rz (timezone_t tz, time_t const *t, struct tm *tm)
   return tm;
 }
 
-static _Noreturn void
+static AVOID
 invalid_time_zone_specification (Lisp_Object zone)
 {
   xsignal2 (Qerror, build_string ("Invalid time zone specification"), zone);
@@ -337,7 +337,7 @@ time_overflow (void)
   error ("Specified time is not representable");
 }
 
-static _Noreturn void
+static AVOID
 time_error (int err)
 {
   switch (err)
@@ -348,7 +348,7 @@ time_error (int err)
     }
 }
 
-static _Noreturn void
+static AVOID
 invalid_hz (Lisp_Object hz)
 {
   xsignal2 (Qerror, build_string ("Invalid time frequency"), hz);
diff --git a/src/xterm.c b/src/xterm.c
index 0facb524549..0b83263a0e6 100644
--- a/src/xterm.c
+++ b/src/xterm.c
@@ -1505,37 +1505,8 @@ x_draw_fringe_bitmap (struct window *w, struct glyph_row *row, struct draw_fring
                             Glyph display
  ***********************************************************************/
 
-
-
-static void x_set_glyph_string_clipping (struct glyph_string *);
-static void x_set_glyph_string_gc (struct glyph_string *);
-static void x_draw_glyph_string_foreground (struct glyph_string *);
-static void x_draw_composite_glyph_string_foreground (struct glyph_string *);
-static void x_draw_glyph_string_box (struct glyph_string *);
-static void x_draw_glyph_string  (struct glyph_string *);
-static _Noreturn void x_delete_glyphs (struct frame *, int);
-static void x_compute_glyph_string_overhangs (struct glyph_string *);
-static void x_set_cursor_gc (struct glyph_string *);
-static void x_set_mode_line_face_gc (struct glyph_string *);
-static void x_set_mouse_face_gc (struct glyph_string *);
 static bool x_alloc_lighter_color (struct frame *, Display *, Colormap,
                                    unsigned long *, double, int);
-static void x_setup_relief_color (struct frame *, struct relief *,
-                                  double, int, unsigned long);
-static void x_setup_relief_colors (struct glyph_string *);
-static void x_draw_image_glyph_string (struct glyph_string *);
-static void x_draw_image_relief (struct glyph_string *);
-static void x_draw_image_foreground (struct glyph_string *);
-#ifndef USE_CAIRO
-static void x_draw_image_foreground_1 (struct glyph_string *, Pixmap);
-#endif
-static void x_clear_glyph_string_rect (struct glyph_string *, int,
-                                       int, int, int);
-static void x_draw_relief_rect (struct frame *, int, int, int, int,
-                                int, bool, bool, bool, bool, bool,
-                                XRectangle *);
-static void x_draw_box_rect (struct glyph_string *, int, int, int, int,
-                             int, bool, bool, XRectangle *);
 static void x_scroll_bar_clear (struct frame *);
 
 #ifdef GLYPH_DEBUG
@@ -3975,7 +3946,7 @@ x_shift_glyphs_for_insert (struct frame *f, int x, int y, int width, int height,
    for X frames.  */
 
 static void
-x_delete_glyphs (struct frame *f, register int n)
+x_delete_glyphs (struct frame *f, int n)
 {
   emacs_abort ();
 }
@@ -9842,7 +9813,7 @@ static char *error_msg;
 /* Handle the loss of connection to display DPY.  ERROR_MESSAGE is
    the text of an error message that lead to the connection loss.  */
 
-static _Noreturn void
+static AVOID
 x_connection_closed (Display *dpy, const char *error_message, bool ioerror)
 {
   struct x_display_info *dpyinfo = x_display_info_for_display (dpy);
@@ -10005,7 +9976,7 @@ x_error_quitter (Display *display, XErrorEvent *event)
    It kills all frames on the display that we lost touch with.
    If that was the only one, it prints an error message and kills Emacs.  */
 
-static _Noreturn int
+static _Noreturn ATTRIBUTE_COLD int
 x_io_error_quitter (Display *display)
 {
   char buf[256];