* [PATCH v2] linux-user: Fix clang warning for nios2-linux-user code
@ 2022-01-11 8:29 Peter Maydell
2022-01-11 9:00 ` Laurent Vivier
0 siblings, 1 reply; 3+ messages in thread
From: Peter Maydell @ 2022-01-11 8:29 UTC (permalink / raw)
To: qemu-devel; +Cc: Richard Henderson, Laurent Vivier, Warner Losh
The clang in Ubuntu 18.04 (10.0.0-4ubuntu1) produces a warning
on the code added in commit f5ef0e518d03 where we use a
shifted expression in a boolean context:
../../linux-user/elfload.c:2423:16: error: converting the result of '<<' to a boolean always evaluates to true [-Werror,-Wtautological-constant-compare]
} else if (LO_COMMPAGE) {
^
../../linux-user/elfload.c:1102:22: note: expanded from macro 'LO_COMMPAGE'
#define LO_COMMPAGE TARGET_PAGE_SIZE
^
/mnt/nvmedisk/linaro/qemu-from-laptop/qemu/include/exec/cpu-all.h:231:31: note: expanded from macro 'TARGET_PAGE_SIZE'
#define TARGET_PAGE_SIZE (1 << TARGET_PAGE_BITS)
^
1 error generated.
The warning is bogus because whether LO_COMMPAGE is zero or not
depends on compile-time ifdefs; shut the compiler up by adding
an explicit comparison to zero.
Fixes: f5ef0e518d0331 ("linux-user/nios2: Map a real kuser page")
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
---
v1->v2: fix sense of comparison (oops!)
linux-user/elfload.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/linux-user/elfload.c b/linux-user/elfload.c
index 329b2375ef1..d3274edfdb7 100644
--- a/linux-user/elfload.c
+++ b/linux-user/elfload.c
@@ -2420,7 +2420,7 @@ static void pgb_static(const char *image_name, abi_ulong orig_loaddr,
} else {
offset = -(HI_COMMPAGE & -align);
}
- } else if (LO_COMMPAGE) {
+ } else if (LO_COMMPAGE != 0) {
loaddr = MIN(loaddr, LO_COMMPAGE & -align);
}
--
2.25.1
^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [PATCH v2] linux-user: Fix clang warning for nios2-linux-user code
2022-01-11 8:29 [PATCH v2] linux-user: Fix clang warning for nios2-linux-user code Peter Maydell
@ 2022-01-11 9:00 ` Laurent Vivier
2022-01-12 11:47 ` Peter Maydell
0 siblings, 1 reply; 3+ messages in thread
From: Laurent Vivier @ 2022-01-11 9:00 UTC (permalink / raw)
To: Peter Maydell, qemu-devel; +Cc: Richard Henderson, Warner Losh
Le 11/01/2022 à 09:29, Peter Maydell a écrit :
> The clang in Ubuntu 18.04 (10.0.0-4ubuntu1) produces a warning
> on the code added in commit f5ef0e518d03 where we use a
> shifted expression in a boolean context:
>
> ../../linux-user/elfload.c:2423:16: error: converting the result of '<<' to a boolean always evaluates to true [-Werror,-Wtautological-constant-compare]
> } else if (LO_COMMPAGE) {
> ^
> ../../linux-user/elfload.c:1102:22: note: expanded from macro 'LO_COMMPAGE'
> #define LO_COMMPAGE TARGET_PAGE_SIZE
> ^
> /mnt/nvmedisk/linaro/qemu-from-laptop/qemu/include/exec/cpu-all.h:231:31: note: expanded from macro 'TARGET_PAGE_SIZE'
> #define TARGET_PAGE_SIZE (1 << TARGET_PAGE_BITS)
> ^
> 1 error generated.
>
> The warning is bogus because whether LO_COMMPAGE is zero or not
> depends on compile-time ifdefs; shut the compiler up by adding
> an explicit comparison to zero.
>
> Fixes: f5ef0e518d0331 ("linux-user/nios2: Map a real kuser page")
> Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
> ---
> v1->v2: fix sense of comparison (oops!)
>
> linux-user/elfload.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/linux-user/elfload.c b/linux-user/elfload.c
> index 329b2375ef1..d3274edfdb7 100644
> --- a/linux-user/elfload.c
> +++ b/linux-user/elfload.c
> @@ -2420,7 +2420,7 @@ static void pgb_static(const char *image_name, abi_ulong orig_loaddr,
> } else {
> offset = -(HI_COMMPAGE & -align);
> }
> - } else if (LO_COMMPAGE) {
> + } else if (LO_COMMPAGE != 0) {
> loaddr = MIN(loaddr, LO_COMMPAGE & -align);
> }
>
Reviewed-by: Laurent Vivier <laurent@vivier.eu>
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH v2] linux-user: Fix clang warning for nios2-linux-user code
2022-01-11 9:00 ` Laurent Vivier
@ 2022-01-12 11:47 ` Peter Maydell
0 siblings, 0 replies; 3+ messages in thread
From: Peter Maydell @ 2022-01-12 11:47 UTC (permalink / raw)
To: Laurent Vivier; +Cc: Richard Henderson, qemu-devel, Warner Losh
On Tue, 11 Jan 2022 at 09:00, Laurent Vivier <laurent@vivier.eu> wrote:
>
> Le 11/01/2022 à 09:29, Peter Maydell a écrit :
> > The clang in Ubuntu 18.04 (10.0.0-4ubuntu1) produces a warning
> > on the code added in commit f5ef0e518d03 where we use a
> > shifted expression in a boolean context:
> >
> > ../../linux-user/elfload.c:2423:16: error: converting the result of '<<' to a boolean always evaluates to true [-Werror,-Wtautological-constant-compare]
> > } else if (LO_COMMPAGE) {
> > ^
> > ../../linux-user/elfload.c:1102:22: note: expanded from macro 'LO_COMMPAGE'
> > #define LO_COMMPAGE TARGET_PAGE_SIZE
> > ^
> > /mnt/nvmedisk/linaro/qemu-from-laptop/qemu/include/exec/cpu-all.h:231:31: note: expanded from macro 'TARGET_PAGE_SIZE'
> > #define TARGET_PAGE_SIZE (1 << TARGET_PAGE_BITS)
> > ^
> > 1 error generated.
> >
> > The warning is bogus because whether LO_COMMPAGE is zero or not
> > depends on compile-time ifdefs; shut the compiler up by adding
> > an explicit comparison to zero.
> >
> > Fixes: f5ef0e518d0331 ("linux-user/nios2: Map a real kuser page")
> > Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
> > ---
> > v1->v2: fix sense of comparison (oops!)
> >
> > linux-user/elfload.c | 2 +-
> > 1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/linux-user/elfload.c b/linux-user/elfload.c
> > index 329b2375ef1..d3274edfdb7 100644
> > --- a/linux-user/elfload.c
> > +++ b/linux-user/elfload.c
> > @@ -2420,7 +2420,7 @@ static void pgb_static(const char *image_name, abi_ulong orig_loaddr,
> > } else {
> > offset = -(HI_COMMPAGE & -align);
> > }
> > - } else if (LO_COMMPAGE) {
> > + } else if (LO_COMMPAGE != 0) {
> > loaddr = MIN(loaddr, LO_COMMPAGE & -align);
> > }
> >
>
> Reviewed-by: Laurent Vivier <laurent@vivier.eu>
Thanks; applied to master as a build fix.
-- PMM
^ permalink raw reply [flat|nested] 3+ messages in thread
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2022-01-11 8:29 [PATCH v2] linux-user: Fix clang warning for nios2-linux-user code Peter Maydell
2022-01-11 9:00 ` Laurent Vivier
2022-01-12 11:47 ` Peter Maydell
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