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

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Message-ID: <20250113150253.3097820-10-masahiroy@kernel.org>
Date: Tue, 14 Jan 2025 00:00:47 +0900
From: Masahiro Yamada <masahiroy@...nel.org>
To: linux-kbuild@...r.kernel.org
Cc: linux-kernel@...r.kernel.org,
	Masahiro Yamada <masahiroy@...nel.org>
Subject: [PATCH 09/17] genksyms: record attributes consistently for init-declarator

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@...nel.org>
---

 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