> -----Original Message----- > From: Peter Maydell [mailto:peter.mayd...@linaro.org] > Sent: Thursday, October 29, 2020 4:15 AM > To: Thomas Huth <th...@redhat.com> > Cc: Philippe Mathieu-Daudé <f4...@amsat.org>; Chenqun (kuhn) > <kuhn.chen...@huawei.com>; QEMU Developers <qemu-devel@nongnu.org>; > QEMU Trivial <qemu-triv...@nongnu.org>; Yoshinori Sato > <ys...@users.sourceforge.jp>; Magnus Damm <magnus.d...@gmail.com>; > Zhanghailiang <zhang.zhanghaili...@huawei.com>; ganqixin > <ganqi...@huawei.com>; Euler Robot <euler.ro...@huawei.com> > Subject: Re: [PATCH 9/9] hw/timer/renesas_tmr: silence the compiler warnings > > On Wed, 28 Oct 2020 at 15:07, Thomas Huth <th...@redhat.com> wrote: > > > > On 28/10/2020 10.59, Philippe Mathieu-Daudé wrote: > > > On 10/28/20 5:18 AM, Chen Qun wrote: > > >> When using -Wimplicit-fallthrough in our CFLAGS, the compiler showed > warning: > > >> ../hw/timer/renesas_tmr.c: In function ‘tmr_read’: > > >> ../hw/timer/renesas_tmr.c:221:19: warning: this statement may fall > through [-Wimplicit-fallthrough=] > > >> 221 | } else if (ch == 0) {i > > >> | ^ > > >> ../hw/timer/renesas_tmr.c:224:5: note: here > > >> 224 | case A_TCORB: > > >> | ^~~~ > > >> > > >> Add the corresponding "fall through" comment to fix it. > > >> > > >> Reported-by: Euler Robot <euler.ro...@huawei.com> > > >> Signed-off-by: Chen Qun <kuhn.chen...@huawei.com> > > >> --- > > >> Cc: Yoshinori Sato <ys...@users.sourceforge.jp> > > >> Cc: Magnus Damm <magnus.d...@gmail.com> > > >> --- > > >> hw/timer/renesas_tmr.c | 1 + > > >> 1 file changed, 1 insertion(+) > > >> > > >> diff --git a/hw/timer/renesas_tmr.c b/hw/timer/renesas_tmr.c index > > >> 446f2eacdd..e03a8155b2 100644 > > >> --- a/hw/timer/renesas_tmr.c > > >> +++ b/hw/timer/renesas_tmr.c > > >> @@ -221,6 +221,7 @@ static uint64_t tmr_read(void *opaque, hwaddr > addr, unsigned size) > > >> } else if (ch == 0) { > > >> return concat_reg(tmr->tcora); > > >> } > > >> + /* fall through */ > > >> case A_TCORB: > > >> if (size == 1) { > > >> return tmr->tcorb[ch]; > > >> > > > > > > You fixed A_TCORA but not A_TCORB... > > > > A_TCORB cannot fall through, since it always does a "return" in both > > branches of the if-statement. > > > > However, it also looks really odd that A_TCORA falls through to > > A_TCORB here and return that register value instead. Is this really > > intended? Yoshinori, could you please double-check whether this is a bug > > here, > or intended? > > See the discussion in this thread: > https://lore.kernel.org/qemu-devel/CAFEAcA8c2dywr=Zxz1ExAV-48JwFU5vbBD > DfA=_ke98xamn...@mail.gmail.com/ > from when Coverity spotting the fall-through. > > I think this cleanup patch from Yoshinori deals with the fall-through stuff by > cleaning up that area of the timer device: > https://lore.kernel.org/qemu-devel/20200711154242.41222-1-ys...@users.so > urceforge.jp/ > It just needs somebody to code-review it :-)
This cleanup patch has been modified more thoroughly, so let's wait for it merge :-) Thanks, Chen Qun
