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/editfns.c b/src/editfns.c
index 050eb2ac6ec..316d9408065 100644
--- a/src/editfns.c
+++ b/src/editfns.c
@@ -3887,9 +3887,12 @@ styled_format (ptrdiff_t nargs, Lisp_Object *args, bool message)
   ptrdiff_t formatlen = SBYTES (args[0]);
 
   /* Allocate the info and discarded tables.  */
-  if ((SIZE_MAX - formatlen) / sizeof (struct info) <= nargs)
+  ptrdiff_t alloca_size;
+  if (INT_MULTIPLY_WRAPV (nargs, sizeof *info, &alloca_size)
+      || INT_ADD_WRAPV (sizeof *info, alloca_size, &alloca_size)
+      || INT_ADD_WRAPV (formatlen, alloca_size, &alloca_size)
+      || SIZE_MAX < alloca_size)
     memory_full (SIZE_MAX);
-  size_t alloca_size = (nargs + 1) * sizeof *info + formatlen;
   /* info[0] is unused.  Unused elements have -1 for start.  */
   info = SAFE_ALLOCA (alloca_size);
   memset (info, 0, alloca_size);