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 <yamada.masahiro@socionext.com>
Signed-off-by: Christian Lamparter <chunkeey@gmail.com>

diff --git a/config/lkc_proto.h b/config/lkc_proto.h
index c46929fab7d97401dd7d88c0207c9fdbd7e366c4..2b16d6e1b2dbd9874fd822763035c644b8888924 100644 (file)
--- a/config/lkc_proto.h
+++ b/config/lkc_proto.h
@@ -50,6 +50,8 @@ const char * prop_get_type_name(enum prop_type type);
 
 /* preprocess.c */
 void env_write_dep(FILE *f, const char *auto_conf_name);
+void variable_add(const char *name, const char *value);
+void variable_all_del(void);
 char *expand_string(const char *in);
 char *expand_dollar(const char **str);
 char *expand_one_token(const char **str);

diff --git a/config/preprocess.c b/config/preprocess.c
index 528be594e1d01f6d03b729e43fdc0fccf20b0001..46487fe6b36cd99e9ea04cc0bc2cbe7708b98121 100644 (file)
--- a/config/preprocess.c
+++ b/config/preprocess.c
@@ -177,6 +177,72 @@ static char *function_expand(const char *name, int argc, char *argv[])
        return NULL;
 }
 
+/*
+ * Variables (and user-defined functions)
+ */
+static LIST_HEAD(variable_list);
+
+struct variable {
+       char *name;
+       char *value;
+       struct list_head node;
+};
+
+static struct variable *variable_lookup(const char *name)
+{
+       struct variable *v;
+
+       list_for_each_entry(v, &variable_list, node) {
+               if (!strcmp(name, v->name))
+                       return v;
+       }
+
+       return NULL;
+}
+
+static char *variable_expand(const char *name, int argc, char *argv[])
+{
+       struct variable *v;
+
+       v = variable_lookup(name);
+       if (!v)
+               return NULL;
+
+       return expand_string_with_args(v->value, argc, argv);
+}
+
+void variable_add(const char *name, const char *value)
+{
+       struct variable *v;
+
+       v = variable_lookup(name);
+       if (v) {
+               free(v->value);
+       } else {
+               v = xmalloc(sizeof(*v));
+               v->name = xstrdup(name);
+               list_add_tail(&v->node, &variable_list);
+       }
+
+       v->value = xstrdup(value);
+}
+
+static void variable_del(struct variable *v)
+{
+       list_del(&v->node);
+       free(v->name);
+       free(v->value);
+       free(v);
+}
+
+void variable_all_del(void)
+{
+       struct variable *v, *tmp;
+
+       list_for_each_entry_safe(v, tmp, &variable_list, node)
+               variable_del(v);
+}
+
 /*
  * Evaluate a clause with arguments.  argc/argv are arguments from the upper
  * function call.
@@ -185,14 +251,26 @@ static char *function_expand(const char *name, int argc, char *argv[])
  */
 static char *eval_clause(const char *str, size_t len, int argc, char *argv[])
 {
-       char *tmp, *name, *res, *prev, *p;
+       char *tmp, *name, *res, *endptr, *prev, *p;
        int new_argc = 0;
        char *new_argv[FUNCTION_MAX_ARGS];
        int nest = 0;
        int i;
+       unsigned long n;
 
        tmp = xstrndup(str, len);
 
+       /*
+        * If variable name is '1', '2', etc.  It is generally an argument
+        * from a user-function call (i.e. local-scope variable).  If not
+        * available, then look-up global-scope variables.
+        */
+       n = strtoul(tmp, &endptr, 10);
+       if (!*endptr && n > 0 && n <= argc) {
+               res = xstrdup(argv[n - 1]);
+               goto free_tmp;
+       }
+
        prev = p = tmp;
 
        /*
@@ -238,6 +316,11 @@ static char *eval_clause(const char *str, size_t len, int argc, char *argv[])
                new_argv[i] = expand_string_with_args(new_argv[i + 1],
                                                      argc, argv);
 
+       /* Search for variables */
+       res = variable_expand(name, new_argc, new_argv);
+       if (res)
+               goto free;
+
        /* Look for built-in functions */
        res = function_expand(name, new_argc, new_argv);
        if (res)
@@ -255,6 +338,7 @@ free:
        for (i = 0; i < new_argc; i++)
                free(new_argv[i]);
        free(name);
+free_tmp:
        free(tmp);
 
        return res;

diff --git a/config/zconf.l b/config/zconf.l
index fde86ba2d0372c3e91713db262adff7b9fa705f1..f1add9536c029ec77b01361dc8c4ac92265cd02b 100644 (file)
--- a/config/zconf.l
+++ b/config/zconf.l
@@ -1,12 +1,13 @@
 %option nostdinit noyywrap never-interactive full ecs
 %option 8bit nodefault yylineno
-%x COMMAND HELP STRING PARAM
+%x COMMAND HELP STRING PARAM ASSIGN_VAL
 %{
 /*
  * Copyright (C) 2002 Roman Zippel <zippel@linux-m68k.org>
  * Released under the terms of the GNU GPL v2.0.
  */
 
+#include <assert.h>
 #include <limits.h>
 #include <stdio.h>
 #include <stdlib.h>
@@ -111,8 +112,10 @@ n  [A-Za-z0-9_-]
                }
                alloc_string(yytext, yyleng);
                yylval.string = text;
-               return T_WORD;
+               return T_VARIABLE;
        }
+       "="     { BEGIN(ASSIGN_VAL); return T_ASSIGN; }
+       [[:blank:]]+
        .       warn_ignored_character(*yytext);
        \n      {
                BEGIN(INITIAL);
@@ -120,6 +123,16 @@ n  [A-Za-z0-9_-]
        }
 }
 
+<ASSIGN_VAL>{
+       [^[:blank:]\n]+.*       {
+               alloc_string(yytext, yyleng);
+               yylval.string = text;
+               return T_ASSIGN_VAL;
+       }
+       \n      { BEGIN(INITIAL); return T_EOL; }
+       .
+}
+
 <PARAM>{
        "&&"    return T_AND;
        "||"    return T_OR;

diff --git a/config/zconf.y b/config/zconf.y
index e31e3d38740c4e8ba0d402b6e3b3344dfa497b6b..addd4a68b549c5557a5ba41781e1a31d96ed7729 100644 (file)
--- a/config/zconf.y
+++ b/config/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 <string> T_VARIABLE
+%token T_ASSIGN
+%token <string> T_ASSIGN_VAL
 
 %left T_OR
 %left T_AND
@@ -92,7 +95,7 @@ static struct menu *current_menu, *current_entry;
 %type <id> end
 %type <id> option_name
 %type <menu> if_entry menu_entry choice_entry
-%type <string> symbol_option_arg word_opt
+%type <string> 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)
@@ -526,6 +539,10 @@ 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)