These two attributes are no longer useful now that Rust has decided to leave
segmented stacks behind. It is assumed that the rust task's stack is always
large enough to make an FFI call (due to the stack being very large).
There's always the case of stack overflow, however, to consider. This does not
change the behavior of stack overflow in Rust. This is still normally triggered
by the __morestack function and aborts the whole process.
C stack overflow will continue to corrupt the stack, however (as it did before
this commit as well). The future improvement of a guard page at the end of every
rust stack is still unimplemented and is intended to be the mechanism through
which we attempt to detect C stack overflow.
Closes#8822Closes#10155
Region pointers were considered a scalar type, so compare_scalar_type would
get called to compare region pointers in trans. This would fail, since
compare_scalar_type has no case for region pointers.
Changed type_is_scalar to return false for region pointers. This had the side
effect of breaking casts to types of the form &T. To ameliorate that, I added
library functions ptr::assimilate (taking a &T to a *T) and ptr::to_uint
(taking a &T to a uint), both of which use reinterpret_cast.
While I was at it, I removed ty::type_has_resources, which is dead code.
