Re: [Qemu-devel] Handling of fall through code (was: [PATCH v8 04/87] target/mips: Mark switch fallthroughs with interpretable comments

[Aleksandar Markovic]

> ...this is the list of warnings for target/mips/translate.c:

> /home/debian/src/github/qemu/qemu/target/mips/translate.c:10047:13: warning: 
> this statement may fall through [-Wimplicit-fallthrough=]
> /home/debian/src/github/qemu/qemu/target/mips/translate.c:10056:13: warning: 
> this statement may fall through [-Wimplicit-fallthrough=]
> /home/debian/src/github/qemu/qemu/target/mips/translate.c:20138:13: warning: 
> this statement may fall through [-Wimplicit-fallthrough=]
> /home/debian/src/github/qemu/qemu/target/mips/translate.c:20144:13: warning: 
> this statement may fall through [-Wimplicit-fallthrough=]
> /home/debian/src/github/qemu/qemu/target/mips/translate.c:6739:9: warning: 
> this statement may fall through [-Wimplicit-fallthrough=]
> /home/debian/src/github/qemu/qemu/target/mips/translate.c:9820:13: warning: 
> this statement may fall through [-Wimplicit-fallthrough=]
> /home/debian/src/github/qemu/qemu/target/mips/translate.c:9829:13: warning: 
> this statement may fall through [-Wimplicit-fallthrough=]

They are all real issues. Two of them are cases of missing '/* fall through */' 
(I plan to send fixes for them in 4.2 timeframe) and five of them are cases of 
missing 'break' (I plan to send corresponding fixes for 4.1 in few days).

Last time I checked gcc 'implicit-fallthrough' option was around five months 
ago, and meanwhile some new code with missing annotation sneaked in. However, 
there is some news - it appears to me that gcc 8 improved that feature 
significantly compared to gcc 7: some cases now detected by gcc 8 are simply 
went undetected by gcc 7. It appears that at least some of such cases are 
ignored by Coverity too.

Great info! Thanks again!!

Aleksandar




> Stefan