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, 10 insertions, 21 deletions

diff --git a/src/data.c b/src/data.c
index 4db93f5625f..ccec15f430a 100644
--- a/src/data.c
+++ b/src/data.c
@@ -2631,30 +2631,16 @@ arith_driver (enum arithop code, ptrdiff_t nargs, Lisp_Object *args)
       switch (code)
         {
         case Aadd:
-          if (INT_ADD_OVERFLOW (accum, next))
-            {
-              overflow = 1;
-              accum &= INTMASK;
-            }
-          accum += next;
+          overflow |= INT_ADD_WRAPV (accum, next, &accum);
           break;
         case Asub:
-          if (INT_SUBTRACT_OVERFLOW (accum, next))
-            {
-              overflow = 1;
-              accum &= INTMASK;
-            }
-          accum = argnum ? accum - next : nargs == 1 ? - next : next;
+          if (! argnum)
+            accum = nargs == 1 ? - next : next;
+          else
+            overflow |= INT_SUBTRACT_WRAPV (accum, next, &accum);
           break;
         case Amult:
-          if (INT_MULTIPLY_OVERFLOW (accum, next))
-            {
-              EMACS_UINT a = accum, b = next, ab = a * b;
-              overflow = 1;
-              accum = ab & INTMASK;
-            }
-          else
-            accum *= next;
+          overflow |= INT_MULTIPLY_WRAPV (accum, next, &accum);
           break;
         case Adiv:
           if (! (argnum || nargs == 1))
@@ -2663,7 +2649,10 @@ arith_driver (enum arithop code, ptrdiff_t nargs, Lisp_Object *args)
             {
               if (next == 0)
                 xsignal0 (Qarith_error);
-              accum /= next;
+              if (INT_DIVIDE_OVERFLOW (accum, next))
+                overflow = true;
+              else
+                accum /= next;
             }
           break;
         case Alogand: