kconfig: make "Selected by:" and "Implied by:" readable

Reverse dependency expressions can get rather unwieldy, especially if
a symbol is selected by more than a handful of other symbols. I.e. it's
possible to have near endless expressions like:
   A && B && !C || D || F && (G || H) || [...]

Chop these expressions into actually readable chunks:
   - A && B && !C
   - D
   - F && (G || H)
   - [...]

I.e. transform the top level OR tokens into newlines and prepend each
line with a minus. This makes the "Selected by:" and "Implied by:" blurb
much easier to read. This is done only if there is more than one top
level OR. "Depends on:" and "Range :" were deliberately left as they are.

Based on idea from Paul Bolle.

Suggested-by: Paul Bolle <pebolle@tiscali.nl>
Signed-off-by: Petr Vorel <petr.vorel@gmail.com>
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>

1 files changed, 24 insertions, 4 deletions

diff --git a/scripts/kconfig/expr.c b/scripts/kconfig/expr.c
index fd8a416ceab7..04fa71e058b7 100644
--- a/scripts/kconfig/expr.c
+++ b/scripts/kconfig/expr.c
@@ -1176,7 +1176,7 @@ struct expr *expr_simplify_unmet_dep(struct expr *e1, struct expr *e2)
         return expr_get_leftmost_symbol(ret);
 }
 
-void expr_print(struct expr *e, void (*fn)(void *, struct symbol *, const char *), void *data, int prevtoken)
+static void __expr_print(struct expr *e, void (*fn)(void *, struct symbol *, const char *), void *data, int prevtoken, bool revdep)
 {
         if (!e) {
                 fn(data, NULL, "y");
@@ -1231,9 +1231,14 @@ void expr_print(struct expr *e, void (*fn)(void *, struct symbol *, const char *
                 fn(data, e->right.sym, e->right.sym->name);
                 break;
         case E_OR:
-                expr_print(e->left.expr, fn, data, E_OR);
-                fn(data, NULL, " || ");
-                expr_print(e->right.expr, fn, data, E_OR);
+                if (revdep && e->left.expr->type != E_OR)
+                        fn(data, NULL, "\n  - ");
+                __expr_print(e->left.expr, fn, data, E_OR, revdep);
+                if (revdep)
+                        fn(data, NULL, "\n  - ");
+                else
+                        fn(data, NULL, " || ");
+                __expr_print(e->right.expr, fn, data, E_OR, revdep);
                 break;
         case E_AND:
                 expr_print(e->left.expr, fn, data, E_AND);
@@ -1266,6 +1271,11 @@ void expr_print(struct expr *e, void (*fn)(void *, struct symbol *, const char *
                 fn(data, NULL, ")");
 }
 
+void expr_print(struct expr *e, void (*fn)(void *, struct symbol *, const char *), void *data, int prevtoken)
+{
+        __expr_print(e, fn, data, prevtoken, false);
+}
+
 static void expr_print_file_helper(void *data, struct symbol *sym, const char *str)
 {
         xfwrite(str, strlen(str), 1, data);
@@ -1310,3 +1320,13 @@ void expr_gstr_print(struct expr *e, struct gstr *gs)
 {
         expr_print(e, expr_print_gstr_helper, gs, E_NONE);
 }
+
+/*
+ * Transform the top level "||" tokens into newlines and prepend each
+ * line with a minus. This makes expressions much easier to read.
+ * Suitable for reverse dependency expressions.
+ */
+void expr_gstr_print_revdep(struct expr *e, struct gstr *gs)
+{
+        __expr_print(e, expr_print_gstr_helper, gs, E_NONE, true);
+}