[PATCH 4/5] kconfig.h: allow to use IS_{ENABLE,REACHABLE} in macro expansion
The typical usage of IS_ENABLED() is
if (IS_ENABLED(CONFIG_FOO)) {
...
}
or
#if IS_ENABLED(CONFIG_FOO)
...
#endif
The current implementation of IS_ENABLED() includes "||" operator,
which works well in those expressions like above.
However, there is a case where we want to evaluate a config option
beyond those use cases.
For example, the OF_TABLE() in include/asm-generic/vmlinux.lds.h
needs to evaluate a config option in macro expansion:
#define ___OF_TABLE(cfg, name) _OF_TABLE_##cfg(name)
#define __OF_TABLE(cfg, name) ___OF_TABLE(cfg, name)
#define OF_TABLE(cfg, name) __OF_TABLE(config_enabled(cfg), name)
#define _OF_TABLE_0(name)
#define _OF_TABLE_1(name) \
...
Here, we can not use IS_ENABLED() because of the "||" operator in
its define. It is true config_enabled() works well, but it is a bit
ambiguous to be used against config options.
This commit makes IS_ENABLED() available in more generic context by
calculating "or" with macro expansion only.
Do likewise for IS_REACHABLE().
Signed-off-by: Masahiro Yamada
---
include/linux/kconfig.h | 24 ++--
1 file changed, 18 insertions(+), 6 deletions(-)
diff --git a/include/linux/kconfig.h b/include/linux/kconfig.h
index 722c7d2..15ec117 100644
--- a/include/linux/kconfig.h
+++ b/include/linux/kconfig.h
@@ -3,6 +3,21 @@
#include
+#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.
@@ -16,12 +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)___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)
-#define __take_second_arg(__ignored, val, ...) val
/*
* IS_BUILTIN(CONFIG_FOO) evaluates to 1 if CONFIG_FOO is set to 'y', 0
@@ -42,14 +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) (IS_BUILTIN(option) || \
-(IS_MODULE(option) && __is_defined(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 */
--
1.9.1
[PATCH 4/5] kconfig.h: allow to use IS_{ENABLE,REACHABLE} in macro expansion
The typical usage of IS_ENABLED() is
if (IS_ENABLED(CONFIG_FOO)) {
...
}
or
#if IS_ENABLED(CONFIG_FOO)
...
#endif
The current implementation of IS_ENABLED() includes "||" operator,
which works well in those expressions like above.
However, there is a case where we want to evaluate a config option
beyond those use cases.
For example, the OF_TABLE() in include/asm-generic/vmlinux.lds.h
needs to evaluate a config option in macro expansion:
#define ___OF_TABLE(cfg, name) _OF_TABLE_##cfg(name)
#define __OF_TABLE(cfg, name) ___OF_TABLE(cfg, name)
#define OF_TABLE(cfg, name) __OF_TABLE(config_enabled(cfg), name)
#define _OF_TABLE_0(name)
#define _OF_TABLE_1(name) \
...
Here, we can not use IS_ENABLED() because of the "||" operator in
its define. It is true config_enabled() works well, but it is a bit
ambiguous to be used against config options.
This commit makes IS_ENABLED() available in more generic context by
calculating "or" with macro expansion only.
Do likewise for IS_REACHABLE().
Signed-off-by: Masahiro Yamada
---
include/linux/kconfig.h | 24 ++--
1 file changed, 18 insertions(+), 6 deletions(-)
diff --git a/include/linux/kconfig.h b/include/linux/kconfig.h
index 722c7d2..15ec117 100644
--- a/include/linux/kconfig.h
+++ b/include/linux/kconfig.h
@@ -3,6 +3,21 @@
#include
+#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.
@@ -16,12 +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)___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)
-#define __take_second_arg(__ignored, val, ...) val
/*
* IS_BUILTIN(CONFIG_FOO) evaluates to 1 if CONFIG_FOO is set to 'y', 0
@@ -42,14 +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) (IS_BUILTIN(option) || \
-(IS_MODULE(option) && __is_defined(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 */
--
1.9.1
