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Subject[PATCH v2 09/21] kconfig: add 'macro' keyword to support user-defined function
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Now, we got a basic ability to test compiler capability in Kconfig.

config CC_HAS_STACKPROTECTOR
def_bool $(shell (($CC -Werror -fstack-protector -c -x c /dev/null -o /dev/null) && echo y) || echo n)

This works, but it is ugly to repeat this long boilerplate.

We want to describe like this:

config CC_HAS_STACKPROTECTOR
bool
default $(cc-option -fstack-protector)

It is straight-forward to add a new function, but I do not like to
hard-code specialized functions like this. Hence, here is another
feature to add functions from Kconfig files.

A user-defined function is defined with a special keyword 'macro'.
It can be referenced in the same way as built-in functions. This
feature was also inspired by Makefile where user-defined functions
are referenced by $(call func-name, args...), but I omitted the 'call'
to makes it shorter.

The macro definition can contain $(1), $(2), ... which will be replaced
with arguments from the caller. The macro works just as a textual
shorthand, which is also expanded in the lexer phase.

[Example Code]

macro success $(shell ($(1) && echo y) || echo n)

config TRUE
bool "true"
default $(success true)

config FALSE
bool "false"
default $(success false)

[Result]

$ make -s alldefconfig
$ tail -n 2 .config
CONFIG_TRUE=y
# CONFIG_FALSE is not set

[Example Code]

macro success $(shell ($(1) && echo y) || echo n)

macro cc-option $(success $CC -Werror $(1) -c -x c /dev/null -o /dev/null)

config CC_HAS_STACKPROTECTOR
def_bool $(cc-option -fstack-protector)

[Result]
$ make -s alldefconfig
$ tail -n 1 .config
CONFIG_CC_HAS_STACKPROTECTOR=y

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
---

Reminder for myself:
Update Documentation/kbuild/kconfig-language.txt

Changes in v2:
- Use 'macro' directly instead of inside the string type symbol.

scripts/kconfig/function.c | 59 +++++++++++++++++++++++++++++++++++++++++++--
scripts/kconfig/lkc_proto.h | 1 +
scripts/kconfig/zconf.l | 31 ++++++++++++++++++++++++
3 files changed, 89 insertions(+), 2 deletions(-)

diff --git a/scripts/kconfig/function.c b/scripts/kconfig/function.c
index 913685f..389bb44 100644
--- a/scripts/kconfig/function.c
+++ b/scripts/kconfig/function.c
@@ -15,6 +15,7 @@ static LIST_HEAD(function_list);
struct function {
char *name;
char *(*func)(struct function *f, int argc, char *argv[]);
+ char *macro;
struct list_head node;
};

@@ -31,7 +32,8 @@ static struct function *func_lookup(const char *name)
}

static void func_add(const char *name,
- char *(*func)(struct function *f, int argc, char *argv[]))
+ char *(*func)(struct function *f, int argc, char *argv[]),
+ const char *macro)
{
struct function *f;

@@ -44,6 +46,7 @@ static void func_add(const char *name,
f = xmalloc(sizeof(*f));
f->name = xstrdup(name);
f->func = func;
+ f->macro = macro ? xstrdup(macro) : NULL;

list_add_tail(&f->node, &function_list);
}
@@ -51,6 +54,7 @@ static void func_add(const char *name,
static void func_del(struct function *f)
{
list_del(&f->node);
+ free(f->macro);
free(f->name);
free(f);
}
@@ -108,6 +112,57 @@ char *func_eval_n(const char *func, size_t n)
return res;
}

+/* run user-defined function */
+static char *do_macro(struct function *f, int argc, char *argv[])
+{
+ char *new;
+ char *src, *p, *res;
+ size_t newlen;
+ int n;
+
+ new = xmalloc(1);
+ *new = 0;
+
+ /*
+ * This is a format string. $(1), $(2), ... must be replaced with
+ * function arguments.
+ */
+ src = f->macro;
+ p = src;
+
+ while ((p = strstr(p, "$("))) {
+ if (isdigit(p[2]) && p[3] == ')') {
+ n = p[2] - '0';
+ if (n < argc) {
+ newlen = strlen(new) + (p - src) +
+ strlen(argv[n]) + 1;
+ new = xrealloc(new, newlen);
+ strncat(new, src, p - src);
+ strcat(new, argv[n]);
+ src = p + 4;
+ }
+ p += 2;
+ }
+ p += 2;
+ }
+
+ newlen = strlen(new) + strlen(src) + 1;
+ new = xrealloc(new, newlen);
+ strcat(new, src);
+
+ res = expand_string_value(new);
+
+ free(new);
+
+ return res;
+}
+
+/* add user-defined function (macro) */
+void func_add_macro(const char *name, const char *macro)
+{
+ func_add(name, do_macro, macro);
+}
+
/* built-in functions */
static char *do_shell(struct function *f, int argc, char *argv[])
{
@@ -157,7 +212,7 @@ static char *do_shell(struct function *f, int argc, char *argv[])
void func_init(void)
{
/* register built-in functions */
- func_add("shell", do_shell);
+ func_add("shell", do_shell, NULL);
}

void func_exit(void)
diff --git a/scripts/kconfig/lkc_proto.h b/scripts/kconfig/lkc_proto.h
index 09a4f53..48699c0 100644
--- a/scripts/kconfig/lkc_proto.h
+++ b/scripts/kconfig/lkc_proto.h
@@ -50,6 +50,7 @@ const char * prop_get_type_name(enum prop_type type);

/* function.c */
char *func_eval_n(const char *func, size_t n);
+void func_add_macro(const char *name, const char *macro);
void func_init(void);
void func_exit(void);

diff --git a/scripts/kconfig/zconf.l b/scripts/kconfig/zconf.l
index 551ca47..6a18c68 100644
--- a/scripts/kconfig/zconf.l
+++ b/scripts/kconfig/zconf.l
@@ -74,6 +74,36 @@ static void warn_ignored_character(char chr)
"%s:%d:warning: ignoring unsupported character '%c'\n",
zconf_curname(), zconf_lineno(), chr);
}
+
+static void handle_macro(const char *text)
+{
+ char *p, *q;
+
+ while (isspace(*text))
+ text++;
+
+ p = xstrdup(text);
+
+ q = p;
+ while (isalnum(*q) || *q == '_' || *q == '-')
+ q++;
+
+ if (q == p || !*q) {
+ yyerror("invalid\n");
+ goto free;
+ }
+
+ *q = '\0';
+
+ q++;
+ while (isspace(*q))
+ q++;
+
+ func_add_macro(p, q);
+free:
+ free(p);
+}
+
%}

n [A-Za-z0-9_-]
@@ -82,6 +112,7 @@ n [A-Za-z0-9_-]
int str = 0;
int ts, i;

+"macro"[ \t].* handle_macro(yytext + 6);
[ \t]*#.*\n |
[ \t]*\n {
return T_EOL;
--
2.7.4
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