From 9ced3bddec080e974e910bf887715540a8d9d96b Mon Sep 17 00:00:00 2001 From: Masahiro Yamada Date: Mon, 28 May 2018 18:21:49 +0900 Subject: kconfig: support user-defined function and recursively expanded variable Now, we got a basic ability to test compiler capability in Kconfig. config CC_HAS_STACKPROTECTOR def_bool $(shell,($(CC) -Werror -fstack-protector -E -x c /dev/null -o /dev/null 2>/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 that. Hence, here is another feature, user-defined function. This works as a textual shorthand with parameterization. A user-defined function is defined by using the = operator, and can be referenced in the same way as built-in functions. A user-defined function in Make is referenced like $(call my-func,arg1,arg2), but I omitted the 'call' to make the syntax shorter. The definition of a user-defined function contains $(1), $(2), etc. in its body to reference the parameters. It is grammatically valid to pass more or fewer arguments when calling it. We already exploit this feature in our makefiles; scripts/Kbuild.include defines cc-option which takes two arguments at most, but most of the callers pass only one argument. By the way, a variable is supported as a subset of this feature since a variable is "a user-defined function with zero argument". In this context, I mean "variable" as recursively expanded variable. I will add a different flavored variable in the next commit. The code above can be written as follows: [Example Code] success = $(shell,($(1)) >/dev/null 2>&1 && echo y || echo n) cc-option = $(success,$(CC) -Werror $(1) -E -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 --- scripts/kconfig/zconf.y | 19 ++++++++++++++++++- 1 file changed, 18 insertions(+), 1 deletion(-) (limited to 'scripts/kconfig/zconf.y') diff --git a/scripts/kconfig/zconf.y b/scripts/kconfig/zconf.y index 8a82aaf27581..e15e8c7063e0 100644 --- a/scripts/kconfig/zconf.y +++ b/scripts/kconfig/zconf.y @@ -77,6 +77,9 @@ static struct menu *current_menu, *current_entry; %token T_CLOSE_PAREN %token T_OPEN_PAREN %token T_EOL +%token T_VARIABLE +%token T_ASSIGN +%token T_ASSIGN_VAL %left T_OR %left T_AND @@ -92,7 +95,7 @@ static struct menu *current_menu, *current_entry; %type end %type option_name %type if_entry menu_entry choice_entry -%type symbol_option_arg word_opt +%type symbol_option_arg word_opt assign_val %destructor { fprintf(stderr, "%s:%d: missing end statement for this entry\n", @@ -143,6 +146,7 @@ common_stmt: | config_stmt | menuconfig_stmt | source_stmt + | assignment_stmt ; option_error: @@ -511,6 +515,15 @@ symbol: nonconst_symbol word_opt: /* empty */ { $$ = NULL; } | T_WORD +/* assignment statement */ + +assignment_stmt: T_VARIABLE T_ASSIGN assign_val T_EOL { variable_add($1, $3); free($1); free($3); } + +assign_val: + /* empty */ { $$ = xstrdup(""); }; + | T_ASSIGN_VAL +; + %% void conf_parse(const char *name) @@ -525,6 +538,10 @@ void conf_parse(const char *name) if (getenv("ZCONF_DEBUG")) yydebug = 1; yyparse(); + + /* Variables are expanded in the parse phase. We can free them here. */ + variable_all_del(); + if (yynerrs) exit(1); if (!modules_sym) -- cgit