Hi, To support applications that assume big-endian memory layout on little- endian systems, I'm considering adding support for reversing the storage order to GCC. In contrast to the existing scalar storage order support for structs, the goal is to reverse the storage order for all memory operations to achieve maximum compatibility with the behavior on big-endian systems, as far as observable by the application.
The plan is to insert byte swapping instructions as part of the RTL expansion of GIMPLE assignments that access memory. This would leverage code that was added for -fsso-struct, keeping the code simple and maintainable. It should not be necessary to insert byte swapping instructions for spilled registers. Is this something that GCC upstream would be interested to accept? To facilitate byte swapping at endian boundaries (kernel or libraries), I'm also considering developing a new GCC builtin that can byte-swap whole structs in memory. There are limitations to this, e.g., unions could not be supported in general. However, I still expect this to be very useful. Any comments or suggestions? Best regards, Jürg
