RFR: 8326936: RISC-V: Shenandoah GC crashes due to incorrect atomic memory operations [v2]

[MaxXing]

On Thu, 29 Feb 2024 06:40:19 GMT, Gui Cao <gcao at openjdk.org> wrote:

>> MaxXing has updated the pull request incrementally with one additional commit since the last revision:
>> 
>>   Remove unnecessary sign-extension.
>
> Hi, When I use this patch, it doesn't compile, and reports the following error msg:
> 
> /home/zifeihan/jdk/src/hotspot/os_cpu/linux_riscv/atomic_linux_riscv.hpp:190:27: note: the comparison reduces to ‘(1 >= 8)’
>   190 |   STATIC_ASSERT(byte_size >= 8);
> /home/zifeihan/jdk/src/hotspot/share/utilities/debug.hpp:289:44: note: in definition of macro ‘STATIC_ASSERT’
>    ... (rest of output omitted)
> * For target hotspot_variant-server_libjvm_objs_arraycopynode.o:
> In file included from /home/zifeihan/jdk/src/hotspot/share/memory/allocation.hpp:29,
>                  from /home/zifeihan/jdk/src/hotspot/share/classfile/classLoaderData.hpp:28,
>                  from /home/zifeihan/jdk/src/hotspot/share/precompiled/precompiled.hpp:34:
> /home/zifeihan/jdk/src/hotspot/os_cpu/linux_riscv/atomic_linux_riscv.hpp: In instantiation of ‘T Atomic::PlatformCmpxchg<byte_size>::operator()(volatile T*, T, T, atomic_memory_order) const [with T = unsigned char; long unsigned int byte_size = 1]’:
> /home/zifeihan/jdk/src/hotspot/share/runtime/atomic.hpp:1026:40:   required from ‘T Atomic::CmpxchgImpl<T, T, T, typename std::enable_if<std::is_integral<_Tp>::value, void>::type>::operator()(volatile T*, T, T, atomic_memory_order) const [with T = unsigned char; typename std::enable_if<std::is_integral<_Tp>::value, void>::type = void]’
> /home/zifeihan/jdk/src/hotspot/share/runtime/atomic.hpp:1002:32:   required from ‘static D Atomic::cmpxchg(volatile D*, U, T, atomic_memory_order) [with D = unsigned char; U = unsigned char; T = unsigned char]’
> /home/zifeihan/jdk/src/hotspot/share/oops/methodData.hpp:216:46:   required from here
> /home/zifeihan/jdk/src/hotspot/os_cpu/linux_riscv/atomic_linux_riscv.hpp:190:27: error: static assertion failed: byte_size >= 8
>   190 |   STATIC_ASSERT(byte_size >= 8);
> /home/zifeihan/jdk/src/hotspot/share/utilities/debug.hpp:289:44: note: in definition of macro ‘STATIC_ASSERT’
>   289 | #define STATIC_ASSERT(Cond) static_assert((Cond), #Cond)
>       |                                            ^~~~
> /home/zifeihan/jdk/src/hotspot/os_cpu/linux_riscv/atomic_linux_riscv.hpp:190:27: note: the comparison reduces to ‘(1 >= 8)’
>   190 |   STATIC_ASSERT(byte_size >= 8);
> /home/zifeihan/jdk/src/hotspot/share/utilities/debug.hpp:289:44: note: in definition of macro ‘STATIC_ASSERT’
>    ... (rest of output omitted)
> * For target hotspot_variant-server_libjvm_objs_assembler.o:
> In file included from /home/zifeihan/jdk/src/hotspot/share/memory/allocation.hpp:29,
>                  from /home/zifeihan...

@zifeihan 

Sorry for that, I fixed this assertion in the latest commit. Now it should compile. Please let me know if not.

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PR Comment: https://git.openjdk.org/jdk/pull/18039#issuecomment-1970538021