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ZGC: Don't use memset to initialize array of ZForwardingTableEntry

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    • Icon: Bug Bug
    • Resolution: Fixed
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    • --with-jvm-features=zgc

    • gc
    • b23

        Use placement new instead of memset() to avoid compiler warning/error when using GCC 8 with -Werror=class-memaccess (memset to initialize non-trivial object).

        Fails in zForwardingTable.cpp:42:
         memset(_table, ZForwardingTableEntry::empty(), _size * sizeof(ZForwardingTableEntry));

        Note that this setup() function is a bit performance sensitive, so the memset() here likely performs much better than a for-loop with placement new. An alternative would be to turn ZForwardingTableEntry into a trivial object and continue using memset(), but that requires some more code restructuring.

        Once could perhaps also argue that (Mmap|Malloc)ArrayAllocator should do the placement new loop, so that it always returns a properly constructed array.

              pliden Per Liden (Inactive)
              dchuyko Dmitry Chuyko
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