summaryrefslogtreecommitdiff
path: root/scripts
diff options
context:
space:
mode:
authorMasahiro Yamada <masahiroy@kernel.org>2024-07-08 00:38:04 +0900
committerMasahiro Yamada <masahiroy@kernel.org>2024-07-16 16:07:14 +0900
commit8bfd6f0923cd7e48aa5d9e5a4e20af818a32c30a (patch)
tree7ba8223d9e2d0836b21363f6b547e8fe2a549edb /scripts
parentd67015eedd9722cfbf9d929be743ce27dfcd0744 (diff)
downloadlwn-8bfd6f0923cd7e48aa5d9e5a4e20af818a32c30a.tar.gz
lwn-8bfd6f0923cd7e48aa5d9e5a4e20af818a32c30a.zip
kconfig: call expr_eliminate_yn() at least once in expr_eliminate_dups()
Kconfig simplifies expressions, but redundant '&&' and '||' operators involving constant symbols 'y' and 'n' are sometimes trimmed and sometimes not. [Test Code] config DEP def_bool y config A bool "A" depends on DEP && y config B bool "B" depends on DEP && y && y [Result] $ make helpnewconfig [ snip ] ----- There is no help available for this option. Symbol: A [=n] Type : bool Defined at Kconfig:4 Prompt: A Depends on: DEP [=y] && y [=y] Location: -> A (A [=n]) ----- ----- There is no help available for this option. Symbol: B [=n] Type : bool Defined at Kconfig:8 Prompt: B Depends on: DEP [=y] Location: -> B (B [=n]) ----- The dependency for A, 'DEP && y', remains as-is, while that for B, 'DEP && y && y', has been reduced to 'DEP'. Currently, expr_eliminate_dups() calls expr_eliminate_yn() only when trans_count != 0, in other words, only when expr_eliminate_dups1() has trimmed at least one leaf. It fails to trim a single '&& y', etc. To fix this inconsistent behavior, expr_eliminate_yn() should be called at least once even if no leaf has been trimmed. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Diffstat (limited to 'scripts')
-rw-r--r--scripts/kconfig/expr.c7
1 files changed, 2 insertions, 5 deletions
diff --git a/scripts/kconfig/expr.c b/scripts/kconfig/expr.c
index 6d4b5a5a1e62..b2dfd3123a5d 100644
--- a/scripts/kconfig/expr.c
+++ b/scripts/kconfig/expr.c
@@ -637,7 +637,7 @@ struct expr *expr_eliminate_dups(struct expr *e)
return e;
oldcount = trans_count;
- while (1) {
+ do {
trans_count = 0;
switch (e->type) {
case E_OR: case E_AND:
@@ -645,11 +645,8 @@ struct expr *expr_eliminate_dups(struct expr *e)
default:
;
}
- if (!trans_count)
- /* No simplifications done in this pass. We're done */
- break;
e = expr_eliminate_yn(e);
- }
+ } while (trans_count); /* repeat until we get no more simplifications */
trans_count = oldcount;
return e;
}