[PATCH 09/17] genksyms: record attributes consistently for init-declarator

From: Masahiro Yamada
Date: Mon Jan 13 2025 - 10:12:42 EST


I believe the missing action here is a bug.

For rules with no explicit action, the following default is used:

{ $$ = $1; }

However, in this case, $1 is the value of attribute_opt itself. As a
result, the value of attribute_opt is always NULL.

The following test code demonstrates inconsistent behavior.

int x __attribute__((__aligned__(4)));
int y __attribute__((__aligned__(4))) = 0;

The attribute is recorded only when followed by an initializer.

This commit adds the correct action to propagate the value of the
ATTRIBUTE_PHRASE token.

With this change, the attribute in the example above is consistently
recorded for both 'x' and 'y'.

[Before]

$ cat <<EOF | scripts/genksyms/genksyms -d
int x __attribute__((__aligned__(4)));
int y __attribute__((__aligned__(4))) = 0;
EOF
Defn for type0 x == <int x >
Defn for type0 y == <int y __attribute__ ( ( __aligned__ ( 4 ) ) ) >
Hash table occupancy 2/4096 = 0.000488281

[After]

$ cat <<EOF | scripts/genksyms/genksyms -d
int x __attribute__((__aligned__(4)));
int y __attribute__((__aligned__(4))) = 0;
EOF
Defn for type0 x == <int x __attribute__ ( ( __aligned__ ( 4 ) ) ) >
Defn for type0 y == <int y __attribute__ ( ( __aligned__ ( 4 ) ) ) >
Hash table occupancy 2/4096 = 0.000488281

Signed-off-by: Masahiro Yamada <masahiroy@xxxxxxxxxx>
---

scripts/genksyms/parse.y | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/scripts/genksyms/parse.y b/scripts/genksyms/parse.y
index 33a6aab53b69..e3c160046143 100644
--- a/scripts/genksyms/parse.y
+++ b/scripts/genksyms/parse.y
@@ -480,7 +480,7 @@ member_bitfield_declarator:

attribute_opt:
/* empty */ { $$ = NULL; }
- | attribute_opt ATTRIBUTE_PHRASE
+ | attribute_opt ATTRIBUTE_PHRASE { $$ = $2; }
;

enum_body:
--
2.43.0