kconfig: improve the recursive dependency report

This commit improves the messages of the recursive dependency.
Currently, sym->dir_dep.expr is not checked.  Hence, any dependency
in property visibility is regarded as the dependency of the symbol.

[Test Code 1]

  config A
          bool "a"
          depends on B

  config B
          bool "b"
          depends on A

[Test Code 2]

  config A
          bool "a" if B

  config B
          bool "b"
          depends on A

For both cases above, the same message is displayed:

        symbol B depends on A
        symbol A depends on B

This commit changes the message for the latter, like this:

        symbol B depends on A
        symbol A prompt is visible depending on B

Also, 'select' and 'imply' are distinguished.

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Tested-by: Dirk Gouders <dirk@gouders.net>

2 files changed, 37 insertions, 17 deletions

diff --git a/scripts/kconfig/symbol.c b/scripts/kconfig/symbol.c
index 90e706096af8..703b9b899ee9 100644
--- a/scripts/kconfig/symbol.c
+++ b/scripts/kconfig/symbol.c
@@ -1011,7 +1011,7 @@ static struct dep_stack {
         struct dep_stack *prev, *next;
         struct symbol *sym;
         struct property *prop;
-        struct expr *expr;
+        struct expr **expr;
 } *check_top;
 
 static void dep_stack_insert(struct dep_stack *stack, struct symbol *sym)
@@ -1076,31 +1076,42 @@ static void sym_check_print_recursive(struct symbol *last_sym)
                         fprintf(stderr, "%s:%d:error: recursive dependency detected!\n",
                                 prop->file->name, prop->lineno);
 
-                if (stack->expr) {
-                        fprintf(stderr, "%s:%d:\tsymbol %s %s value contains %s\n",
-                                prop->file->name, prop->lineno,
+                if (sym_is_choice(sym)) {
+                        fprintf(stderr, "%s:%d:\tchoice %s contains symbol %s\n",
+                                menu->file->name, menu->lineno,
+                                sym->name ? sym->name : "<choice>",
+                                next_sym->name ? next_sym->name : "<choice>");
+                } else if (sym_is_choice_value(sym)) {
+                        fprintf(stderr, "%s:%d:\tsymbol %s is part of choice %s\n",
+                                menu->file->name, menu->lineno,
                                 sym->name ? sym->name : "<choice>",
-                                prop_get_type_name(prop->type),
                                 next_sym->name ? next_sym->name : "<choice>");
-                } else if (stack->prop) {
+                } else if (stack->expr == &sym->dir_dep.expr) {
                         fprintf(stderr, "%s:%d:\tsymbol %s depends on %s\n",
                                 prop->file->name, prop->lineno,
                                 sym->name ? sym->name : "<choice>",
                                 next_sym->name ? next_sym->name : "<choice>");
-                } else if (sym_is_choice(sym)) {
-                        fprintf(stderr, "%s:%d:\tchoice %s contains symbol %s\n",
-                                menu->file->name, menu->lineno,
+                } else if (stack->expr == &sym->rev_dep.expr) {
+                        fprintf(stderr, "%s:%d:\tsymbol %s is selected by %s\n",
+                                prop->file->name, prop->lineno,
                                 sym->name ? sym->name : "<choice>",
                                 next_sym->name ? next_sym->name : "<choice>");
-                } else if (sym_is_choice_value(sym)) {
-                        fprintf(stderr, "%s:%d:\tsymbol %s is part of choice %s\n",
-                                menu->file->name, menu->lineno,
+                } else if (stack->expr == &sym->implied.expr) {
+                        fprintf(stderr, "%s:%d:\tsymbol %s is implied by %s\n",
+                                prop->file->name, prop->lineno,
                                 sym->name ? sym->name : "<choice>",
                                 next_sym->name ? next_sym->name : "<choice>");
+                } else if (stack->expr) {
+                        fprintf(stderr, "%s:%d:\tsymbol %s %s value contains %s\n",
+                                prop->file->name, prop->lineno,
+                                sym->name ? sym->name : "<choice>",
+                                prop_get_type_name(prop->type),
+                                next_sym->name ? next_sym->name : "<choice>");
                 } else {
-                        fprintf(stderr, "%s:%d:\tsymbol %s is selected or implied by %s\n",
+                        fprintf(stderr, "%s:%d:\tsymbol %s %s is visible depending on %s\n",
                                 prop->file->name, prop->lineno,
                                 sym->name ? sym->name : "<choice>",
+                                prop_get_type_name(prop->type),
                                 next_sym->name ? next_sym->name : "<choice>");
                 }
         }
@@ -1157,14 +1168,23 @@ static struct symbol *sym_check_sym_deps(struct symbol *sym)
 
         dep_stack_insert(&stack, sym);
 
+        stack.expr = &sym->dir_dep.expr;
+        sym2 = sym_check_expr_deps(sym->dir_dep.expr);
+        if (sym2)
+                goto out;
+
+        stack.expr = &sym->rev_dep.expr;
         sym2 = sym_check_expr_deps(sym->rev_dep.expr);
         if (sym2)
                 goto out;
 
+        stack.expr = &sym->implied.expr;
         sym2 = sym_check_expr_deps(sym->implied.expr);
         if (sym2)
                 goto out;
 
+        stack.expr = NULL;
+
         for (prop = sym->prop; prop; prop = prop->next) {
                 if (prop->type == P_CHOICE || prop->type == P_SELECT ||
                     prop->type == P_IMPLY)
@@ -1175,7 +1195,7 @@ static struct symbol *sym_check_sym_deps(struct symbol *sym)
                         break;
                 if (prop->type != P_DEFAULT || sym_is_choice(sym))
                         continue;
-                stack.expr = prop->expr;
+                stack.expr = &prop->expr;
                 sym2 = sym_check_expr_deps(prop->expr);
                 if (sym2)
                         break;
diff --git a/scripts/kconfig/tests/err_recursive_dep/expected_stderr b/scripts/kconfig/tests/err_recursive_dep/expected_stderr
index 2eb25288db8c..84679b104655 100644
--- a/scripts/kconfig/tests/err_recursive_dep/expected_stderr
+++ b/scripts/kconfig/tests/err_recursive_dep/expected_stderr
@@ -1,5 +1,5 @@
 Kconfig:11:error: recursive dependency detected!
-Kconfig:11:     symbol B is selected or implied by B
+Kconfig:11:     symbol B is selected by B
 For a resolution refer to Documentation/kbuild/kconfig-language.txt
 subsection "Kconfig recursive dependency limitations"
 
@@ -15,14 +15,14 @@ For a resolution refer to Documentation/kbuild/kconfig-language.txt
 subsection "Kconfig recursive dependency limitations"
 
 Kconfig:32:error: recursive dependency detected!
-Kconfig:32:     symbol D2 is selected or implied by D1
+Kconfig:32:     symbol D2 is selected by D1
 Kconfig:27:     symbol D1 depends on D2
 For a resolution refer to Documentation/kbuild/kconfig-language.txt
 subsection "Kconfig recursive dependency limitations"
 
 Kconfig:37:error: recursive dependency detected!
 Kconfig:37:     symbol E1 depends on E2
-Kconfig:42:     symbol E2 is selected or implied by E1
+Kconfig:42:     symbol E2 is implied by E1
 For a resolution refer to Documentation/kbuild/kconfig-language.txt
 subsection "Kconfig recursive dependency limitations"