bounds checking and traps

[Jan Beulich]

When I came across the x86 backend emitting int 5 instructions I
wondered what that would be good for, and it seemed obvious that doing
so makes assumptions about the OS the code is to execute on (since there
is no requirement that an OS permit user code to invoke this or any
other software interrupt). I went and checked the sources for how this
could be activated, finding that the TRAP_IF rtl code would be the one.
However, no-where in the entire tree I was able to find a place where
something would actually be set to TRAP_IF, and hoping that I neither
overlooked anything nor that there's any black magic in the picture here
it would seem that all this is either left-overs or uncompleted (for
several years) work.

Can anyone shed any light on this?

Thanks, Jan