Merge tag 'v2.6.38' of git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux-2.6

[mv-sheeva.git] / scripts / kconfig / expr.c

diff --git a/scripts/kconfig/expr.c b/scripts/kconfig/expr.c
index 330e7c0048a85ea1939562e724eaa7f2326d56ab..001003452f6872aef385099f1d660ffa1054a288 100644 (file)
--- a/scripts/kconfig/expr.c
+++ b/scripts/kconfig/expr.c
@@ -64,7 +64,7 @@ struct expr *expr_alloc_or(struct expr *e1, struct expr *e2)
        return e2 ? expr_alloc_two(E_OR, e1, e2) : e1;
 }
 
-struct expr *expr_copy(struct expr *org)
+struct expr *expr_copy(const struct expr *org)
 {
        struct expr *e;
 
@@ -1013,6 +1013,48 @@ int expr_compare_type(enum expr_type t1, enum expr_type t2)
 #endif
 }
 
+static inline struct expr *
+expr_get_leftmost_symbol(const struct expr *e)
+{
+
+       if (e == NULL)
+               return NULL;
+
+       while (e->type != E_SYMBOL)
+               e = e->left.expr;
+
+       return expr_copy(e);
+}
+
+/*
+ * Given expression `e1' and `e2', returns the leaf of the longest
+ * sub-expression of `e1' not containing 'e2.
+ */
+struct expr *expr_simplify_unmet_dep(struct expr *e1, struct expr *e2)
+{
+       struct expr *ret;
+
+       switch (e1->type) {
+       case E_OR:
+               return expr_alloc_and(
+                   expr_simplify_unmet_dep(e1->left.expr, e2),
+                   expr_simplify_unmet_dep(e1->right.expr, e2));
+       case E_AND: {
+               struct expr *e;
+               e = expr_alloc_and(expr_copy(e1), expr_copy(e2));
+               e = expr_eliminate_dups(e);
+               ret = (!expr_eq(e, e1)) ? e1 : NULL;
+               expr_free(e);
+               break;
+               }
+       default:
+               ret = e1;
+               break;
+       }
+
+       return expr_get_leftmost_symbol(ret);
+}
+
 void expr_print(struct expr *e, void (*fn)(void *, struct symbol *, const char *), void *data, int prevtoken)
 {
        if (!e) {