scripts: add muldiv64() checking coccinelle scripts

Signed-off-by: NLaurent Vivier <lvivier@redhat.com>
Signed-off-by: NMichael Tokarev <mjt@tls.msk.ru>

scripts/coccinelle/overflow_muldiv64.cocci

+// Find muldiv64(i64, i64, x) for potential overflow
+@filter@
+typedef uint64_t;
+typedef int64_t;
+{ uint64_t, int64_t, long, unsigned long } a, b;
+expression c;
+position p;
+@@
+
+muldiv64(a,b,c)@p
+
+@script:python@
+p << filter.p;
+@@
+
+cocci.print_main("potential muldiv64() overflow", p)

scripts/coccinelle/remove_muldiv64.cocci

+// replace muldiv64(a, 1, b) by "a / b"
+@@
+expression a, b;
+@@
+-muldiv64(a, 1, b)
++a / b

scripts/coccinelle/simplify_muldiv64.cocci

+// replace muldiv64(i32, i32, x) by (uint64_t)i32 * i32 / x
+@@
+typedef uint32_t;
+typedef int32_t;
+{ uint32_t, int32_t, int, unsigned int } a, b;
+typedef uint64_t;
+expression c;
+@@
+
+-muldiv64(a,b,c)
++(uint64_t) a * b / c

scripts/coccinelle/swap_muldiv64.cocci

+// replace muldiv64(i32, i64, x) by muldiv64(i64, i32, x)
+@@
+typedef uint64_t;
+typedef int64_t;
+typedef uint32_t;
+typedef int32_t;
+{ uint32_t, int32_t, int, unsigned int } a;
+{ uint64_t, int64_t, long, unsigned long } b;
+expression c;
+@@
+
+-muldiv64(a,b,c)
++muldiv64(b,a,c)