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77a92660d8
expr_trans_bool() performs an incorrect transformation.
[Test Code]
config MODULES
def_bool y
modules
config A
def_bool y
select C if B != n
config B
def_tristate m
config C
tristate
[Result]
CONFIG_MODULES=y
CONFIG_A=y
CONFIG_B=m
CONFIG_C=m
This output is incorrect because CONFIG_C=y is expected.
Documentation/kbuild/kconfig-language.rst clearly explains the function
of the '!=' operator:
If the values of both symbols are equal, it returns 'n',
otherwise 'y'.
Therefore, the statement:
select C if B != n
should be equivalent to:
select C if y
Or, more simply:
select C
Hence, the symbol C should be selected by the value of A, which is 'y'.
However, expr_trans_bool() wrongly transforms it to:
select C if B
Therefore, the symbol C is selected by (A && B), which is 'm'.
The comment block of expr_trans_bool() correctly explains its intention:
* bool FOO!=n => FOO
^^^^
If FOO is bool, FOO!=n can be simplified into FOO. This is correct.
However, the actual code performs this transformation when FOO is
tristate:
if (e->left.sym->type == S_TRISTATE) {
^^^^^^^^^^
While it can be fixed to S_BOOLEAN, there is no point in doing so
because expr_tranform() already transforms FOO!=n to FOO when FOO is
bool. (see the "case E_UNEQUAL" part)
expr_trans_bool() is wrong and unnecessary.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Acked-by: Randy Dunlap <rdunlap@infradead.org>
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| .. | ||
| lxdialog | ||
| tests | ||
| .gitignore | ||
| array_size.h | ||
| conf.c | ||
| confdata.c | ||
| expr.c | ||
| expr.h | ||
| gconf-cfg.sh | ||
| gconf.c | ||
| gconf.glade | ||
| hashtable.h | ||
| images.c | ||
| images.h | ||
| internal.h | ||
| lexer.l | ||
| list_types.h | ||
| list.h | ||
| lkc_proto.h | ||
| lkc.h | ||
| Makefile | ||
| mconf-cfg.sh | ||
| mconf.c | ||
| menu.c | ||
| merge_config.sh | ||
| mnconf-common.c | ||
| mnconf-common.h | ||
| nconf-cfg.sh | ||
| nconf.c | ||
| nconf.gui.c | ||
| nconf.h | ||
| parser.y | ||
| preprocess.c | ||
| preprocess.h | ||
| qconf-cfg.sh | ||
| qconf.cc | ||
| qconf.h | ||
| streamline_config.pl | ||
| symbol.c | ||
| util.c | ||