[resend] 8236856: AArch64: Spurious GCC warnings

[Andrew Dinn]

On 09/01/2020 16:09, Andrew Haley wrote:
> With some versions of GCC we get this at compile time, which causes build failures
> when warnings-as-errors is enabled. It's a false positive, and should be fixed in
> GCC, but we need to shut it up.
> 
> Compiling macroAssembler_aarch64.cpp (for libjvm.so)
> In file included from /home/aph/jdk-jdk/src/hotspot/share/runtime/atomic.hpp:632:0,
>                  from /home/aph/jdk-jdk/src/hotspot/share/oops/oop.hpp:33,
>                  from /home/aph/jdk-jdk/src/hotspot/share/runtime/handles.hpp:29,
>                  from /home/aph/jdk-jdk/src/hotspot/share/code/oopRecorder.hpp:28,
>                  from /home/aph/jdk-jdk/src/hotspot/share/asm/codeBuffer.hpp:28,
>                  from /home/aph/jdk-jdk/src/hotspot/share/asm/assembler.hpp:28,
>                  from /home/aph/jdk-jdk/src/hotspot/cpu/aarch64/macroAssembler_aarch64.cpp:30:
> /home/aph/jdk-jdk/src/hotspot/os_cpu/linux_aarch64/atomic_linux_aarch64.hpp: In instantiation of 'T Atomic::PlatformCmpxchg<byte_size>::operator()(volatile T*, T, T, atomic_memory_order) const [with T = signed char; long unsigned int byte_size = 1ul]':
> /home/aph/jdk-jdk/src/hotspot/share/runtime/atomic.hpp:783:46: required from 'T Atomic::CmpxchgImpl<T, T, T, typename EnableIf<(IsIntegral<T>::value || IsRegisteredEnum<T>::value)>::type>::operator()(volatile T*, T, T, atomic_memory_order) const [with T = signed char; typename EnableIf<(IsIntegral<T>::value || IsRegisteredEnum<T>::value)>::type = void]'
> /home/aph/jdk-jdk/src/hotspot/share/runtime/atomic.hpp:756:75: required from 'static D Atomic::cmpxchg(volatile D*, U, T, atomic_memory_order) [with D = signed char; U = signed char; T = signed char]'
> /home/aph/jdk-jdk/src/hotspot/share/gc/shenandoah/shenandoahSharedVariables.hpp:77:113: required from here
> /home/aph/jdk-jdk/src/hotspot/os_cpu/linux_aarch64/atomic_linux_aarch64.hpp:60:10: warning: parameter 'dest' set but not used [-Wunused-but-set-parameter]
> 
> Fixed thusly. OK?
Yes, that looks fine /and/ trivial.

regards,


Andrew Dinn
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Senior Principal Software Engineer
Red Hat UK Ltd
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