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kconfig: call expr_eliminate_yn() at least once in expr_eliminate_dups()

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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>
This commit is contained in:
Masahiro Yamada 2024-07-08 00:38:04 +09:00
parent d67015eedd
commit 8bfd6f0923
1 changed files with 2 additions and 5 deletions
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7
scripts/kconfig/expr.c
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@ -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;
}