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, 3 insertions, 2 deletions

diff --git a/src/keymap.c b/src/keymap.c
index c988d12fe80..c28885ab132 100644
--- a/src/keymap.c
+++ b/src/keymap.c
@@ -1984,9 +1984,10 @@ For an approximate inverse of this, see `kbd'.  */)
     size += XINT (Flength (prefix));
 
   /* This has one extra element at the end that we don't pass to Fconcat.  */
-  if (min (PTRDIFF_MAX, SIZE_MAX) / word_size / 4 < size)
+  EMACS_INT size4;
+  if (INT_MULTIPLY_WRAPV (size, 4, &size4))
     memory_full (SIZE_MAX);
-  SAFE_ALLOCA_LISP (args, size * 4);
+  SAFE_ALLOCA_LISP (args, size4);
 
   /* In effect, this computes
      (mapconcat 'single-key-description keys " ")