[PATCH] kconfig: Document the 'symbol' struct

[PATCH] kconfig: Document the 'symbol' struct

[Ulf Magnusson]

Visibility and choices in particular might be a bit tricky to figure
out.

Also fix existing comment to point out that P_MENU is also used for
menus.

Signed-off-by: Ulf Magnusson <ulfalizer@gmail.com>
---
 scripts/kconfig/expr.h | 45 ++++++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 44 insertions(+), 1 deletion(-)

diff --git a/scripts/kconfig/expr.h b/scripts/kconfig/expr.h
index a73f762..6344067 100644
--- a/scripts/kconfig/expr.h
+++ b/scripts/kconfig/expr.h
@@ -74,17 +74,60 @@ enum {
 	S_DEF_COUNT
 };
 
+/*
+ * Represents a configuration symbol.
+ *
+ * Choices are represented as a special kind of symbol and have the
+ * SYMBOL_CHOICE bit set in 'flags'.
+ */
 struct symbol {
+	/* The next symbol in the same bucket in the symbol hash table */
 	struct symbol *next;
+
+	/* The name of the symbol, e.g. "FOO" for 'config FOO' */
 	char *name;
+
+	/* S_BOOLEAN, S_TRISTATE, ... */
 	enum symbol_type type;
+
+	/*
+	 * The calculated value of the symbol. The SYMBOL_VALID bit is set in
+	 * 'flags' when this is up to date. Note that this value might differ
+	 * from the user value set in e.g. a .config file, due to visibility.
+	 */
 	struct symbol_value curr;
+
+	/*
+	 * Values for the symbol provided from outside. def[S_DEF_USER] holds
+	 * the .config value.
+	 */
 	struct symbol_value def[S_DEF_COUNT];
+
+	/*
+	 * An upper bound on the tristate value the user can set for the symbol
+	 * if it is a boolean or tristate. Calculated from prompt dependencies,
+	 * which also inherit dependencies from enclosing menus, choices, and
+	 * ifs. If 'n', the user value will be ignored.
+	 *
+	 * Symbols lacking prompts always have visibility 'n'.
+	 */
 	tristate visible;
+
+	/* SYMBOL_* flags */
 	int flags;
+
+	/* List of properties. See prop_type. */
 	struct property *prop;
+
+	/* Dependencies from enclosing menus, choices, and ifs */
 	struct expr_value dir_dep;
+
+	/* Reverse dependencies through being selected by other symbols */
 	struct expr_value rev_dep;
+
+	/*
+	 * "Weak" reverse dependencies through being implied by other symbols
+	 */
 	struct expr_value implied;
 };
 
@@ -133,7 +176,7 @@ enum prop_type {
 	P_UNKNOWN,
 	P_PROMPT,   /* prompt "foo prompt" or "BAZ Value" */
 	P_COMMENT,  /* text associated with a comment */
-	P_MENU,     /* prompt associated with a menuconfig option */
+	P_MENU,     /* prompt associated with a menu or menuconfig symbol */
 	P_DEFAULT,  /* default y */
 	P_CHOICE,   /* choice value */
 	P_SELECT,   /* select BAR */
-- 
2.7.4

Re: [PATCH] kconfig: Document the 'symbol' struct

[Ulf Magnusson]

On Wed, Oct 4, 2017 at 7:48 AM, Ulf Magnusson <ulfalizer@gmail.com> wrote:
> Visibility and choices in particular might be a bit tricky to figure
> out.
>
> Also fix existing comment to point out that P_MENU is also used for
> menus.
>
> Signed-off-by: Ulf Magnusson <ulfalizer@gmail.com>
> ---
>  scripts/kconfig/expr.h | 45 ++++++++++++++++++++++++++++++++++++++++++++-
>  1 file changed, 44 insertions(+), 1 deletion(-)
>
> diff --git a/scripts/kconfig/expr.h b/scripts/kconfig/expr.h
> index a73f762..6344067 100644
> --- a/scripts/kconfig/expr.h
> +++ b/scripts/kconfig/expr.h
> @@ -74,17 +74,60 @@ enum {
>         S_DEF_COUNT
>  };
>
> +/*
> + * Represents a configuration symbol.
> + *
> + * Choices are represented as a special kind of symbol and have the
> + * SYMBOL_CHOICE bit set in 'flags'.
> + */
>  struct symbol {
> +       /* The next symbol in the same bucket in the symbol hash table */
>         struct symbol *next;
> +
> +       /* The name of the symbol, e.g. "FOO" for 'config FOO' */
>         char *name;
> +
> +       /* S_BOOLEAN, S_TRISTATE, ... */
>         enum symbol_type type;
> +
> +       /*
> +        * The calculated value of the symbol. The SYMBOL_VALID bit is set in
> +        * 'flags' when this is up to date. Note that this value might differ
> +        * from the user value set in e.g. a .config file, due to visibility.
> +        */
>         struct symbol_value curr;
> +
> +       /*
> +        * Values for the symbol provided from outside. def[S_DEF_USER] holds
> +        * the .config value.
> +        */
>         struct symbol_value def[S_DEF_COUNT];
> +
> +       /*
> +        * An upper bound on the tristate value the user can set for the symbol
> +        * if it is a boolean or tristate. Calculated from prompt dependencies,
> +        * which also inherit dependencies from enclosing menus, choices, and
> +        * ifs. If 'n', the user value will be ignored.
> +        *
> +        * Symbols lacking prompts always have visibility 'n'.
> +        */
>         tristate visible;
> +
> +       /* SYMBOL_* flags */
>         int flags;
> +
> +       /* List of properties. See prop_type. */
>         struct property *prop;
> +
> +       /* Dependencies from enclosing menus, choices, and ifs */
>         struct expr_value dir_dep;
> +
> +       /* Reverse dependencies through being selected by other symbols */
>         struct expr_value rev_dep;
> +
> +       /*
> +        * "Weak" reverse dependencies through being implied by other symbols
> +        */
>         struct expr_value implied;
>  };
>
> @@ -133,7 +176,7 @@ enum prop_type {
>         P_UNKNOWN,
>         P_PROMPT,   /* prompt "foo prompt" or "BAZ Value" */
>         P_COMMENT,  /* text associated with a comment */
> -       P_MENU,     /* prompt associated with a menuconfig option */
> +       P_MENU,     /* prompt associated with a menu or menuconfig symbol */
>         P_DEFAULT,  /* default y */
>         P_CHOICE,   /* choice value */
>         P_SELECT,   /* select BAR */
> --
> 2.7.4
>

Adding some CCs just because I forgot. No panic.

Cheers,
Ulf

Re: [PATCH] kconfig: Document the 'symbol' struct

[Masahiro Yamada]

2017-10-04 14:48 GMT+09:00 Ulf Magnusson <ulfalizer@gmail.com>:
> Visibility and choices in particular might be a bit tricky to figure
> out.
>
> Also fix existing comment to point out that P_MENU is also used for
> menus.
>
> Signed-off-by: Ulf Magnusson <ulfalizer@gmail.com>


Applied to linux-kbuild/kconfig.
Thanks!


-- 
Best Regards
Masahiro Yamada