Home | History | Annotate | Line # | Download | only in lint1 
      1  1.10  rillig /*	$NetBSD: msg_324.c,v 1.10 2024/01/28 08:17:27 rillig Exp $	*/
      2   1.1  rillig # 3 "msg_324.c"
      3   1.1  rillig 
      4   1.7  rillig // Test for message: suggest cast from '%s' to '%s' on op '%s' to avoid overflow [324]
      5   1.1  rillig 
      6   1.2  rillig /*
      7   1.2  rillig  * This warning applies to binary operators if the result of the operator
      8   1.2  rillig  * is converted to a type that is bigger than the operands' result type
      9   1.2  rillig  * after the usual arithmetic promotions.
     10   1.2  rillig  *
     11   1.2  rillig  * In such a case, the operator's result would be truncated to the operator's
     12   1.2  rillig  * result type (invoking undefined behavior for signed integers), and that
     13   1.2  rillig  * truncated value would then be converted.  At that point, a few bits may
     14   1.2  rillig  * have been lost.
     15   1.2  rillig  */
     16   1.2  rillig 
     17   1.9  rillig /* lint1-flags: -g -S -w -P -X 351 */
     18   1.2  rillig 
     19   1.2  rillig void
     20   1.2  rillig example(char c, int i, unsigned u)
     21   1.2  rillig {
     22   1.4  rillig 	long long ll;
     23   1.4  rillig 	unsigned long long ull;
     24   1.2  rillig 
     25  1.10  rillig 	/* expect+2: warning: suggest cast from 'int' to 'long long' on op '+' to avoid overflow [324] */
     26  1.10  rillig 	/* expect+1: warning: 'll' set but not used in function 'example' [191] */
     27   1.6  rillig 	ll = c + i;
     28   1.7  rillig 	/* expect+1: warning: suggest cast from 'int' to 'long long' on op '-' to avoid overflow [324] */
     29   1.6  rillig 	ll = i - c;
     30  1.10  rillig 	/* expect+2: warning: suggest cast from 'unsigned int' to 'unsigned long long' on op '*' to avoid overflow [324] */
     31  1.10  rillig 	/* expect+1: warning: 'ull' set but not used in function 'example' [191] */
     32   1.6  rillig 	ull = c * u;
     33   1.7  rillig 	/* expect+1: warning: suggest cast from 'unsigned int' to 'unsigned long long' on op '+' to avoid overflow [324] */
     34   1.6  rillig 	ull = u + c;
     35   1.7  rillig 	/* expect+1: warning: suggest cast from 'unsigned int' to 'unsigned long long' on op '-' to avoid overflow [324] */
     36   1.6  rillig 	ull = i - u;
     37   1.7  rillig 	/* expect+1: warning: suggest cast from 'unsigned int' to 'unsigned long long' on op '*' to avoid overflow [324] */
     38   1.6  rillig 	ull = u * i;
     39   1.7  rillig 	/* expect+1: warning: suggest cast from 'int' to 'long long' on op '<<' to avoid overflow [324] */
     40   1.6  rillig 	ll = i << c;
     41   1.2  rillig 
     42   1.2  rillig 	/*
     43   1.2  rillig 	 * The operators SHR, DIV and MOD cannot produce an overflow,
     44   1.2  rillig 	 * therefore no warning is necessary for them.
     45   1.2  rillig 	 */
     46   1.4  rillig 	ll = i >> c;
     47   1.4  rillig 	ull = u / c;
     48   1.4  rillig 	ull = u % c;
     49   1.3  rillig 
     50   1.3  rillig 	/*
     51   1.3  rillig 	 * Assigning the result of an increment or decrement operator to a
     52   1.3  rillig 	 * differently-sized type is no unusual that there is no need to warn
     53   1.3  rillig 	 * about it.  It's also more unlikely that there is an actual loss
     54   1.3  rillig 	 * since this only happens for a single value of the old type, unlike
     55   1.4  rillig 	 * "ull = u * u", which has many more possibilities for overflowing.
     56   1.3  rillig 	 */
     57   1.4  rillig 	ull = u++;
     58   1.4  rillig 	ull = ++u;
     59   1.4  rillig 	ull = u--;
     60   1.4  rillig 	ull = --u;
     61   1.2  rillig }
     62