2024-04-29 20:35:04

by Edward Liaw

Subject: [PATCH] selftests/vDSO: Fix assignment in condition without parentheses

Fixes clang compiler warnings by adding parentheses:

parse_vdso.c:65:9: warning: using the result of an assignment as a condition without parentheses [-Wparentheses]
if (g = h & 0xf0000000)
~~^~~~~~~~~~~~~~~~
parse_vdso.c:65:9: note: place parentheses around the assignment to silence this warning
if (g = h & 0xf0000000)
^
( )
parse_vdso.c:65:9: note: use '==' to turn this assignment into an equality comparison
if (g = h & 0xf0000000)
^
==

Fixes: 98eedc3a9dbf ("Document the vDSO and add a reference parser")
Signed-off-by: Edward Liaw <[email protected]>
---
tools/testing/selftests/vDSO/parse_vdso.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tools/testing/selftests/vDSO/parse_vdso.c b/tools/testing/selftests/vDSO/parse_vdso.c
index 413f75620a35..b9cf771006da 100644
--- a/tools/testing/selftests/vDSO/parse_vdso.c
+++ b/tools/testing/selftests/vDSO/parse_vdso.c
@@ -62,7 +62,7 @@ static unsigned long elf_hash(const unsigned char *name)
while (*name)
{
h = (h << 4) + *name++;
- if (g = h & 0xf0000000)
+ if ((g = h & 0xf0000000))
h ^= g >> 24;
h &= ~g;
}
--
2.44.0.769.g3c40516874-goog

2024-04-30 00:18:02

by Justin Stitt

Subject: Re: [PATCH] selftests/vDSO: Fix assignment in condition without parentheses

On Mon, Apr 29, 2024 at 08:34:36PM +0000, Edward Liaw wrote:
> Fixes clang compiler warnings by adding parentheses:
>
> parse_vdso.c:65:9: warning: using the result of an assignment as a condition without parentheses [-Wparentheses]
> if (g = h & 0xf0000000)
> ~~^~~~~~~~~~~~~~~~
> parse_vdso.c:65:9: note: place parentheses around the assignment to silence this warning
> if (g = h & 0xf0000000)
> ^
> ( )
> parse_vdso.c:65:9: note: use '==' to turn this assignment into an equality comparison
> if (g = h & 0xf0000000)
> ^
> ==
>
> Fixes: 98eedc3a9dbf ("Document the vDSO and add a reference parser")
> Signed-off-by: Edward Liaw <[email protected]>

For readability's sake, I tend to prefer just taking the assignment out
of the if statement:

g = h & 0xf0000000;
then testing it:
if (g) ...

but as it stands it's fine and the warning goes away.

Reviewed-by: Justin Stitt <[email protected]>
> ---
> tools/testing/selftests/vDSO/parse_vdso.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/tools/testing/selftests/vDSO/parse_vdso.c b/tools/testing/selftests/vDSO/parse_vdso.c
> index 413f75620a35..b9cf771006da 100644
> --- a/tools/testing/selftests/vDSO/parse_vdso.c
> +++ b/tools/testing/selftests/vDSO/parse_vdso.c
> @@ -62,7 +62,7 @@ static unsigned long elf_hash(const unsigned char *name)
> while (*name)
> {
> h = (h << 4) + *name++;
> - if (g = h & 0xf0000000)
> + if ((g = h & 0xf0000000))
> h ^= g >> 24;
> h &= ~g;
> }
> --
> 2.44.0.769.g3c40516874-goog
>