2013-09-22 17:06:10

by Madhavan Srinivasan

Subject: [PATCH V2] kconfig/menu.c: fix uninitialized variable warning

In file included from scripts/kconfig/zconf.tab.c:2537:0:
scripts/kconfig/menu.c: In function ‘get_symbol_str’:
scripts/kconfig/menu.c:586:18: warning: ‘jump’ may be used uninitialized in
this function [-Wmaybe-uninitialized]
jump->offset = r->len - 1;
^
scripts/kconfig/menu.c:547:19: note: ‘jump’ was declared here
struct jump_key *jump;
^
Change V2:

1)Added comment as suggested.

Signed-off-by: Madhavan Srinivasan <[email protected]>
---
scripts/kconfig/menu.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/scripts/kconfig/menu.c b/scripts/kconfig/menu.c
index c1d5320..32ee2d5 100644
--- a/scripts/kconfig/menu.c
+++ b/scripts/kconfig/menu.c
@@ -544,7 +544,8 @@ static void get_prompt_str(struct gstr *r, struct property *prop,
{
int i, j;
struct menu *submenu[8], *menu, *location = NULL;
- struct jump_key *jump;
+ /* Initializing to avoid a spurious warning observed in gcc 4.8.0 */
+ struct jump_key *jump = NULL;

str_printf(r, _("Prompt: %s\n"), _(prop->text));
menu = prop->menu->parent;
--
1.7.10.4

2013-09-26 17:05:31

by Yann E. MORIN

Subject: Re: [PATCH V2] kconfig/menu.c: fix uninitialized variable warning

Madhavan, All,

On 2013-09-22 22:35 +0530, Madhavan Srinivasan spake thusly:
> In file included from scripts/kconfig/zconf.tab.c:2537:0:
> scripts/kconfig/menu.c: In function ‘get_symbol_str’:
> scripts/kconfig/menu.c:586:18: warning: ‘jump’ may be used uninitialized in
> this function [-Wmaybe-uninitialized]
> jump->offset = r->len - 1;
> ^
> scripts/kconfig/menu.c:547:19: note: ‘jump’ was declared here
> struct jump_key *jump;
> ^
> Change V2:
>
> 1)Added comment as suggested.

Maybe I'm mislead, but I think Benjamin and I suggested a comment that
explained the warning was just spurious, and there would be no code
change. Something like:

/* gcc 4.8.0 on (your distro and version) warns about 'jump may be
* used uninitialized', which is wrong. The warning does not appear
* with gcc != 4.8.0 */
struct jump_key *jump;

This is so, if sometime in the future the code changes, and the variable
is indeeded used uninitialised, we have a proper warning by gcc in this
case.

Care to resend, please?

Regards,
Yann E. MORIN.

> Signed-off-by: Madhavan Srinivasan <[email protected]>
> ---
> scripts/kconfig/menu.c | 3 ++-
> 1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/scripts/kconfig/menu.c b/scripts/kconfig/menu.c
> index c1d5320..32ee2d5 100644
> --- a/scripts/kconfig/menu.c
> +++ b/scripts/kconfig/menu.c
> @@ -544,7 +544,8 @@ static void get_prompt_str(struct gstr *r, struct property *prop,
> {
> int i, j;
> struct menu *submenu[8], *menu, *location = NULL;
> - struct jump_key *jump;
> + /* Initializing to avoid a spurious warning observed in gcc 4.8.0 */
> + struct jump_key *jump = NULL;
>
> str_printf(r, _("Prompt: %s\n"), _(prop->text));
> menu = prop->menu->parent;
> --
> 1.7.10.4
>

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