| Message ID | 20240707153856.2483047-1-masahiroy@kernel.org (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | [1/4] kconfig: call expr_eliminate_yn() at least once in expr_eliminate_dups() | expand |
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; }
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> --- scripts/kconfig/expr.c | 7 ++----- 1 file changed, 2 insertions(+), 5 deletions(-)