Writing down binary data... with padding bytes

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Could freeze intrinsic in rustc be implemented like this?

  • insert a call to an extern function LLVM knows nothing about, say rustFreeze(p) where p is a pointer/ref
  • LLVM will now assume that memory could have been written through p
  • add an extra hand-crafted LLVM pass suitably late in the chain to remove all calls to rustFreeze

This will not be a true freeze because MADV_FREE and friends can still cause the result of reading uninitialized memory to be unpredictable, LLVM undef style. However at least LLVM will not compile the code to NOP or make any other nasty assumptions?