suppress integer overflow warnings

* util.c: annotate as NO_SANITIZE
* bignum.c: avoid (size_t)--
* marshal.c: ditto.


git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@65739 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

bignum.c

@@ -418,15 +418,16 @@ bary_small_lshift(BDIGIT *zds, const BDIGIT *xds, size_t n, int shift)
 static void
 bary_small_rshift(BDIGIT *zds, const BDIGIT *xds, size_t n, int shift, BDIGIT higher_bdigit)
 {
+    size_t i;
     BDIGIT_DBL num = 0;
 
     assert(0 <= shift && shift < BITSPERDIG);
 
     num = BIGUP(higher_bdigit);
-    while (n--) {
-	BDIGIT x = xds[n];
+    for (i = 0; i < n; i++) {
+	BDIGIT x = xds[n - i - 1];
 	num = (num | x) >> shift;
-	zds[n] = BIGLO(num);
+	zds[n - i - 1] = BIGLO(num);
 	num = BIGUP(x);
     }
 }
@@ -445,8 +446,9 @@ bary_zero_p(const BDIGIT *xds, size_t xn)
 static void
 bary_neg(BDIGIT *ds, size_t n)
 {
-    while (n--)
-        ds[n] = BIGLO(~ds[n]);
+    size_t i;
+    for (i = 0; i < n; i++)
+        ds[n - i - 1] = BIGLO(~ds[n - i - 1]);
 }
 
 static int
@@ -5087,6 +5089,7 @@ rb_big2str(VALUE x, int base)
 static unsigned long
 big2ulong(VALUE x, const char *type)
 {
+    size_t i;
     size_t len = BIGNUM_LEN(x);
     unsigned long num;
     BDIGIT *ds;
@@ -5101,9 +5104,9 @@ big2ulong(VALUE x, const char *type)
     num = (unsigned long)ds[0];
 #else
     num = 0;
-    while (len--) {
+    for (i = 0; i < len; i++) {
 	num <<= BITSPERDIG;
-	num += (unsigned long)ds[len]; /* overflow is already checked */
+	num += (unsigned long)ds[len - i - 1]; /* overflow is already checked */
     }
 #endif
     return num;

marshal.c

@@ -817,6 +817,7 @@ w_object(VALUE obj, struct dump_arg *arg, int limit)
 		char sign = BIGNUM_SIGN(obj) ? '+' : '-';
 		size_t len = BIGNUM_LEN(obj);
 		size_t slen;
+                size_t j;
 		BDIGIT *d = BIGNUM_DIGITS(obj);
 
                 slen = SHORTLEN(len);
@@ -826,7 +827,7 @@ w_object(VALUE obj, struct dump_arg *arg, int limit)
 
 		w_byte(sign, arg);
 		w_long((long)slen, arg);
-		while (len--) {
+                for (j = 0; j < len; j++) {
 #if SIZEOF_BDIGIT > SIZEOF_SHORT
 		    BDIGIT num = *d;
 		    int i;
@@ -834,7 +835,7 @@ w_object(VALUE obj, struct dump_arg *arg, int limit)
 		    for (i=0; i<SIZEOF_BDIGIT; i+=SIZEOF_SHORT) {
 			w_short(num & SHORTMASK, arg);
 			num = SHORTDN(num);
-			if (len == 0 && num == 0) break;
+                        if (j == len - 1 && num == 0) break;
 		    }
 #else
 		    w_short(*d, arg);

util.c

@@ -1541,6 +1541,7 @@ cmp(Bigint *a, Bigint *b)
     return 0;
 }
 
+NO_SANITIZE("unsigned-integer-overflow", static Bigint * diff(Bigint *a, Bigint *b));
 static Bigint *
 diff(Bigint *a, Bigint *b)
 {
@@ -2020,6 +2021,7 @@ hexnan(double *rvp, const char **sp)
 #endif /*No_Hex_NaN*/
 #endif /* INFNAN_CHECK */
 
+NO_SANITIZE("unsigned-integer-overflow", double ruby_strtod(const char *s00, char **se));
 double
 ruby_strtod(const char *s00, char **se)
 {