kconfig.h: allow to use IS_{ENABLE,REACHABLE} in macro expansion

[cascardo/linux.git] / include / linux / kconfig.h

diff --git a/include/linux/kconfig.h b/include/linux/kconfig.h
index b33c779..15ec117 100644 (file)
--- a/include/linux/kconfig.h
+++ b/include/linux/kconfig.h
@@ -3,6 +3,21 @@
 
 #include <generated/autoconf.h>
 
+#define __ARG_PLACEHOLDER_1 0,
+#define __take_second_arg(__ignored, val, ...) val
+
+/*
+ * The use of "&&" / "||" is limited in certain expressions.
+ * The followings enable to calculate "and" / "or" with macro expansion only.
+ */
+#define __and(x, y)                    ___and(x, y)
+#define ___and(x, y)                   ____and(__ARG_PLACEHOLDER_##x, y)
+#define ____and(arg1_or_junk, y)       __take_second_arg(arg1_or_junk y, 0)
+
+#define __or(x, y)                     ___or(x, y)
+#define ___or(x, y)                    ____or(__ARG_PLACEHOLDER_##x, y)
+#define ____or(arg1_or_junk, y)                __take_second_arg(arg1_or_junk 1, y)
+
 /*
  * Helper macros to use CONFIG_ options in C/CPP expressions. Note that
  * these only work with boolean and tristate options.
@@ -16,11 +31,10 @@
  * When CONFIG_BOOGER is not defined, we generate a (... 1, 0) pair, and when
  * the last step cherry picks the 2nd arg, we get a zero.
  */
-#define __ARG_PLACEHOLDER_1 0,
-#define config_enabled(cfg) _config_enabled(cfg)
-#define _config_enabled(value) __config_enabled(__ARG_PLACEHOLDER_##value)
-#define __config_enabled(arg1_or_junk) ___config_enabled(arg1_or_junk 1, 0)
-#define ___config_enabled(__ignored, val, ...) val
+#define config_enabled(cfg)            ___is_defined(cfg)
+#define __is_defined(x)                        ___is_defined(x)
+#define ___is_defined(val)             ____is_defined(__ARG_PLACEHOLDER_##val)
+#define ____is_defined(arg1_or_junk)   __take_second_arg(arg1_or_junk 1, 0)
 
 /*
  * IS_BUILTIN(CONFIG_FOO) evaluates to 1 if CONFIG_FOO is set to 'y', 0
@@ -41,14 +55,13 @@
  * This is similar to IS_ENABLED(), but returns false when invoked from
  * built-in code when CONFIG_FOO is set to 'm'.
  */
-#define IS_REACHABLE(option) (config_enabled(option) || \
-                (config_enabled(option##_MODULE) && config_enabled(MODULE)))
+#define IS_REACHABLE(option) __or(IS_BUILTIN(option), \
+                               __and(IS_MODULE(option), __is_defined(MODULE)))
 
 /*
  * IS_ENABLED(CONFIG_FOO) evaluates to 1 if CONFIG_FOO is set to 'y' or 'm',
  * 0 otherwise.
  */
-#define IS_ENABLED(option) \
-       (IS_BUILTIN(option) || IS_MODULE(option))
+#define IS_ENABLED(option) __or(IS_BUILTIN(option), IS_MODULE(option))
 
 #endif /* __LINUX_KCONFIG_H */