[PULL v2 00/14] Compile QEMU with -Wimplicit-fallthrough

[PULL v2 00/14] Compile QEMU with -Wimplicit-fallthrough

[Thomas Huth]

 Hi!

The following changes since commit 75ee62ac606bfc9eb59310b9446df3434bf6e8c2:

  Merge remote-tracking branch 'remotes/ehabkost-gl/tags/x86-next-pull-request'
  into staging (2020-12-17 18:53:36 +0000)

are available in the Git repository at:

  https://gitlab.com/huth/qemu.git tags/pull-request-2020-12-18

for you to fetch changes up to 0a2ebce92a3f10a89843e4a7a8e2f2eba4f7b109:

  configure: Compile with -Wimplicit-fallthrough=2 (2020-12-18 09:15:47 +0100)

----------------------------------------------------------------
* Compile QEMU with -Wimplicit-fallthrough=2 to avoid bugs in
  switch-case statements
----------------------------------------------------------------

 v2:
  - Added the patch for bsd-user
  - Included Philippe's twl92230 break patch

Chen Qun (6):
      hw/timer/renesas_tmr: silence the compiler warnings
      target/i386: silence the compiler warnings in gen_shiftd_rm_T1
      hw/intc/arm_gicv3_kvm: silence the compiler warnings
      accel/tcg/user-exec: silence the compiler warnings
      target/sparc/translate: silence the compiler warnings
      target/sparc/win_helper: silence the compiler warnings

Philippe Mathieu-Daudé (1):
      hw/rtc/twl92230: Add missing 'break'

Thomas Huth (7):
      disas/libvixl: Fix fall-through annotation for GCC >= 7
      target/unicore32/translate: Add missing fallthrough annotations
      hw/rtc/twl92230: Silence warnings about missing fallthrough statements
      tcg/optimize: Add fallthrough annotations
      tests/fp: Do not emit implicit-fallthrough warnings in the softfloat tests
      bsd-user: Silence warnings about missing fallthrough statement
      configure: Compile with -Wimplicit-fallthrough=2

 accel/tcg/user-exec.c                |  3 ++-
 bsd-user/main.c                      |  1 +
 configure                            |  1 +
 disas/libvixl/vixl/a64/disasm-a64.cc |  4 ++++
 disas/libvixl/vixl/globals.h         |  6 +++--
 hw/intc/arm_gicv3_kvm.c              |  8 +++++++
 hw/rtc/twl92230.c                    | 44 ++++++++++++------------------------
 hw/timer/renesas_tmr.c               |  1 +
 include/qemu/compiler.h              | 11 +++++++++
 target/i386/tcg/translate.c          |  7 ++++--
 target/sparc/translate.c             |  2 +-
 target/sparc/win_helper.c            |  2 +-
 target/unicore32/translate.c         |  2 ++
 tcg/optimize.c                       |  4 ++++
 tests/fp/meson.build                 |  2 ++
 15 files changed, 61 insertions(+), 37 deletions(-)

[PULL 12/14] bsd-user: Silence warnings about missing fallthrough statement

[Thomas Huth]

When compiling with -Werror=implicit-fallthrough, the compiler complains
about a missing fallthrough annotation in this file. Looking at the code,
the fallthrough is indeed wanted here, so let's add a proper comment.

Message-Id: <20201217154138.1547274-1-thuth@redhat.com>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Thomas Huth <thuth@redhat.com>
---
 bsd-user/main.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/bsd-user/main.c b/bsd-user/main.c
index 0a918e8f74..9c700c6234 100644
--- a/bsd-user/main.c
+++ b/bsd-user/main.c
@@ -512,6 +512,7 @@ void cpu_loop(CPUSPARCState *env)
         case 0x141:
             if (bsd_type != target_freebsd)
                 goto badtrap;
+            /* fallthrough */
         case 0x100:
 #endif
             syscall_nr = env->gregs[1];
-- 
2.27.0

[PULL 13/14] hw/rtc/twl92230: Add missing 'break'

[Thomas Huth]

From: Philippe Mathieu-Daudé <f4bug@amsat.org>

Add missing 'break' to fix:

  hw/rtc/twl92230.c: In function ‘menelaus_write’:
  hw/rtc/twl92230.c:713:5: error: label at end of compound statement
    713 |     default:
        |     ^~~~~~~

Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Reviewed-by: Thomas Huth <thuth@redhat.com>
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Message-Id: <20201211154605.511714-1-f4bug@amsat.org>
Signed-off-by: Thomas Huth <thuth@redhat.com>
---
 hw/rtc/twl92230.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/hw/rtc/twl92230.c b/hw/rtc/twl92230.c
index a787bd247d..006d75e174 100644
--- a/hw/rtc/twl92230.c
+++ b/hw/rtc/twl92230.c
@@ -697,6 +697,7 @@ static void menelaus_write(void *opaque, uint8_t addr, uint8_t value)
 #ifdef VERBOSE
         printf("%s: unknown register %02x\n", __func__, addr);
 #endif
+        break;
     }
 }
 
-- 
2.27.0

[PULL 14/14] configure: Compile with -Wimplicit-fallthrough=2

[Thomas Huth]

Coverity always complains about switch-case statements that fall through
the next one when there is no comment in between - which could indicate
a forgotten "break" statement. Instead of handling these issues after
they have been committed, it would be better to avoid them in the build
process already. Thus let's enable the -Wimplicit-fallthrough warning now.
The "=2" level seems to be a good compromise between being too strict and
too generic about the possible comments, so we'll start with "=2" for now.

Signed-off-by: Thomas Huth <thuth@redhat.com>
Reviewed-by: Chen Qun <kuhn.chenqun@huawei.com>
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Message-Id: <20201211152426.350966-13-thuth@redhat.com>
Signed-off-by: Thomas Huth <thuth@redhat.com>
---
 configure | 1 +
 1 file changed, 1 insertion(+)

diff --git a/configure b/configure
index c228f7c21e..881af4b6be 100755
--- a/configure
+++ b/configure
@@ -2023,6 +2023,7 @@ add_to warn_flags -Wempty-body
 add_to warn_flags -Wnested-externs
 add_to warn_flags -Wendif-labels
 add_to warn_flags -Wexpansion-to-defined
+add_to warn_flags -Wimplicit-fallthrough=2
 
 nowarn_flags=
 add_to nowarn_flags -Wno-initializer-overrides
-- 
2.27.0

Re: [PULL v2 00/14] Compile QEMU with -Wimplicit-fallthrough

[Peter Maydell]

On Fri, 18 Dec 2020 at 08:27, Thomas Huth <thuth@redhat.com> wrote:
>
>  Hi!
>
> The following changes since commit 75ee62ac606bfc9eb59310b9446df3434bf6e8c2:
>
>   Merge remote-tracking branch 'remotes/ehabkost-gl/tags/x86-next-pull-request'
>   into staging (2020-12-17 18:53:36 +0000)
>
> are available in the Git repository at:
>
>   https://gitlab.com/huth/qemu.git tags/pull-request-2020-12-18
>
> for you to fetch changes up to 0a2ebce92a3f10a89843e4a7a8e2f2eba4f7b109:
>
>   configure: Compile with -Wimplicit-fallthrough=2 (2020-12-18 09:15:47 +0100)
>
> ----------------------------------------------------------------
> * Compile QEMU with -Wimplicit-fallthrough=2 to avoid bugs in
>   switch-case statements
> ----------------------------------------------------------------


Applied, thanks.

Please update the changelog at https://wiki.qemu.org/ChangeLog/6.0
for any user-visible changes.

-- PMM