[PATCH v5 16/31] kconfig: add 'info', 'warning-if', and 'error-if' built-in functions

[Masahiro Yamada]

Syntax:
  $(info,<text>)
  $(warning-if,<condition>,<text>)
  $(error-if,<condition>,<text)

The 'info' function prints a message to stdout as in Make.

The 'warning-if' and 'error-if' are similar to 'warning' and 'error'
in Make, but take the condition parameter.  They are effective only
when the <condition> part is y.

Kconfig does not implement the lazy expansion as used in the 'if'
'and, 'or' functions in Make.  In other words, Kconfig does not
support conditional expansion.  The unconditional 'error' function
would always terminate the parsing, hence would be useless in Kconfig.

Signed-off-by: Masahiro Yamada <yamada.masahiro@xxxxxxxxxxxxx>
Reviewed-by: Kees Cook <keescook@xxxxxxxxxxxx>
---

Changes in v5:
  - Replace 'warning', 'error' with 'warning-if', 'error-if'

Changes in v4:
  - Add 'error' function

Changes in v3: None
Changes in v2: None

 scripts/kconfig/preprocess.c | 27 +++++++++++++++++++++++++++
 1 file changed, 27 insertions(+)

diff --git a/scripts/kconfig/preprocess.c b/scripts/kconfig/preprocess.c
index 56aa1f0..5ee58ee 100644
--- a/scripts/kconfig/preprocess.c
+++ b/scripts/kconfig/preprocess.c
@@ -106,6 +106,21 @@ struct function {
 	char *(*func)(int argc, char *argv[]);
 };
 
+static char *do_error_if(int argc, char *argv[])
+{
+	if (!strcmp(argv[0], "y"))
+		pperror("%s", argv[1]);
+
+	return NULL;
+}
+
+static char *do_info(int argc, char *argv[])
+{
+	printf("%s\n", argv[0]);
+
+	return xstrdup("");
+}
+
 static char *do_shell(int argc, char *argv[])
 {
 	FILE *p;
@@ -146,9 +161,21 @@ static char *do_shell(int argc, char *argv[])
 	return xstrdup(buf);
 }
 
+static char *do_warning_if(int argc, char *argv[])
+{
+	if (!strcmp(argv[0], "y"))
+		fprintf(stderr, "%s:%d: %s\n",
+			current_file->name, yylineno, argv[1]);
+
+	return xstrdup("");
+}
+
 static const struct function function_table[] = {
 	/* Name		MIN	MAX	Function */
+	{ "error-if",	2,	2,	do_error_if },
+	{ "info",	1,	1,	do_info },
 	{ "shell",	1,	1,	do_shell },
+	{ "warning-if",	2,	2,	do_warning_if },
 };
 
 #define FUNCTION_MAX_ARGS		16
-- 
2.7.4