rcx

commit f184ebe57ae8798cdc9e0d8f7df935c708c14e53
parent 0d2db13f14f9a0e8fceed3633e8e38673557b4f3
Author: Robert Russell <robertrussell.72001@gmail.com>
Date:   Sun, 12 Mar 2023 17:47:45 -0700

Add STATIC macro and improve (un)likely macros

We can now write
	if likely(cond) {...}
instead of
	if (likely(cond)) {...}
(and similarly for unlikely) which hints that (un)likely is not part
of the condition.

Diffstat:
M
inc/def.h
 | 
20
++++++++++++++++++--

1 file changed, 18 insertions(+), 2 deletions(-)
diff --git a/inc/def.h b/inc/def.h
@@ -21,8 +21,8 @@
 #ifdef __GNUC__
 #define NOINLINE __attribute__((noinline))
 #define UNUSED __attribute__((unused))
-#define likely(x)   __builtin_expect((x), 1)
-#define unlikely(x) __builtin_expect((x), 0)
+#define likely(x)   (__builtin_expect((x), 1))
+#define unlikely(x) (__builtin_expect((x), 0))
 #else
 #define NOINLINE
 #define UNUSED
@@ -30,6 +30,22 @@
 #define unlikely(x) (x)
 #endif
 
+/* STATIC is a macro for creating static literals. Usage:
+ *     STATIC(int, 3)
+ *     STATIC(char[], "abc")
+ *     STATIC(struct {int a; int b;}, {1, 2})
+ * The result of each of these expressions is a pointer to static data, which
+ * in particular mean it can be passed to functions that retain pointers after
+ * the caller returns. In the last use case, the value argument contains a
+ * comma outside of parentheses, which is why we use varargs in the
+ * implementation. The type argument must never contain a comma outside of
+ * parentheses. */
+#if __STDC_VERSION__ >= 202300L
+#define STATIC(T, ...) (&(static T){__VA_ARGS__})
+#elif defined(__GNUC__)
+#define STATIC(T, ...) ({static __typeof__(T) tmp = __VA_ARGS__; &tmp;})
+#endif
+
 #if CHAR_BIT != 8
 #error "Expected CHAR_BIT == 8"
 #endif