Message ID | 20220110191751.3335516-1-peter.maydell@linaro.org |
---|---|
State | Superseded |
Headers | show |
Series | linux-user: Fix clang warning for nios2-linux-user code | expand |
> On Jan 10, 2022, at 12:17 PM, Peter Maydell <peter.maydell@linaro.org> wrote: > > 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> > --- > I'm probably going to apply this directly once it's reviewed, because > it fixes a build-break on one of my machines. > > linux-user/elfload.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) Reviewed-by: Warner Losh <imp@bsdimp.com> > diff --git a/linux-user/elfload.c b/linux-user/elfload.c > index 329b2375ef1..2993b01e60c 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 > >
Le 10/01/2022 à 20:17, 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> > --- > I'm probably going to apply this directly once it's reviewed, because > it fixes a build-break on one of my machines. > > 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..2993b01e60c 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) { It seems to revert the logic should it be "(LO_COMMPAGE != 0)"? Thanks, Laurent > loaddr = MIN(loaddr, LO_COMMPAGE & -align); > } >
On Tue, 11 Jan 2022 at 07:01, Laurent Vivier <laurent@vivier.eu> wrote: > > Le 10/01/2022 à 20:17, 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> > > --- > > I'm probably going to apply this directly once it's reviewed, because > > it fixes a build-break on one of my machines. > > > > 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..2993b01e60c 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) { > > It seems to revert the logic should it be "(LO_COMMPAGE != 0)"? You're right, it should -- I was too hasty in writing this fix, clearly... -- PMM
diff --git a/linux-user/elfload.c b/linux-user/elfload.c index 329b2375ef1..2993b01e60c 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); }
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> --- I'm probably going to apply this directly once it's reviewed, because it fixes a build-break on one of my machines. linux-user/elfload.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)