Use INT_ADD_WRAPV etc. to check integer overflow

* src/alloc.c (xnmalloc, xnrealloc, xpalloc, Fmake_string):
* src/buffer.c (record_overlay_string, overlay_strings):
* src/casefiddle.c (casify_object):
* src/ccl.c (Fccl_execute_on_string):
* src/character.c (char_width, c_string_width, lisp_string_width)
(count_size_as_multibyte, string_escape_byte8):
* src/coding.c (coding_alloc_by_realloc, produce_chars):
* src/data.c (arith_driver):
* src/dispnew.c (realloc_glyph_pool, init_display):
* src/editfns.c (styled_format):
* src/fns.c (Ffillarray):
* src/ftfont.c (ftfont_shape_by_flt):
* src/gnutls.c (gnutls_hex_string):
* src/gtkutil.c (get_utf8_string):
* src/image.c (x_to_xcolors, x_detect_edges, png_load_body):
* src/keymap.c (Fkey_description):
* src/lisp.h (SAFE_ALLOCA_LISP):
* src/term.c (encode_terminal_code):
* src/tparam.c (tparam1):
* src/xselect.c (x_property_data_to_lisp):
* src/xsmfns.c (smc_save_yourself_CB):
* src/xterm.c (x_term_init):
When checking for integer overflow, prefer INT_MULTIPLY_WRAPV to
more-complicated code involving division and/or
INT_MULTIPLY_OVERFLOW, and similarly for INT_ADD_WRAPV and
subtraction and/or INT_ADD_OVERFLOW.
* src/casefiddle.c (casify_object): Simplify multibyte size check.
* src/character.c: Remove some obsolete ‘#ifdef emacs’s.
* src/data.c (arith_driver): Also check for division overflow,
as that’s now possible given that the accumulator can now contain
any Emacs integer.
* src/lisp.h (lisp_word_count): Remove; no longer used.

1 files changed, 5 insertions, 2 deletions

diff --git a/src/gtkutil.c b/src/gtkutil.c
index 701bcab7060..90683eba7b8 100644
--- a/src/gtkutil.c
+++ b/src/gtkutil.c
@@ -517,9 +517,12 @@ get_utf8_string (const char *str)
       if (cp) g_free (cp);
 
       len = strlen (str);
-      if ((min (PTRDIFF_MAX, SIZE_MAX) - len - 1) / 4 < nr_bad)
+      ptrdiff_t alloc;
+      if (INT_MULTIPLY_WRAPV (nr_bad, 4, &alloc)
+	  || INT_ADD_WRAPV (len + 1, alloc, &alloc)
+	  || SIZE_MAX < alloc)
 	memory_full (SIZE_MAX);
-      up = utf8_str = xmalloc (len + nr_bad * 4 + 1);
+      up = utf8_str = xmalloc (alloc);
       p = (unsigned char *)str;
 
       while (! (cp = g_locale_to_utf8 ((char *)p, -1, &bytes_read,