diff options
Diffstat (limited to 'scripts/kconfig/expr.c')
| -rw-r--r-- | scripts/kconfig/expr.c | 44 |
1 files changed, 43 insertions, 1 deletions
diff --git a/scripts/kconfig/expr.c b/scripts/kconfig/expr.c index 330e7c0048..001003452f 100644 --- 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) { |