rust/src/test/run-pass/monomorphize-abi-alignment.rs
2019-02-10 23:42:32 +00:00

33 lines
990 B
Rust

#![allow(non_upper_case_globals)]
/*!
* On x86_64-linux-gnu and possibly other platforms, structs get 8-byte "preferred" alignment,
* but their "ABI" alignment (i.e., what actually matters for data layout) is the largest alignment
* of any field. (Also, `u64` has 8-byte ABI alignment; this is not always true).
*
* On such platforms, if monomorphize uses the "preferred" alignment, then it will unify
* `A` and `B`, even though `S<A>` and `S<B>` have the field `t` at different offsets,
* and apply the wrong instance of the method `unwrap`.
*/
#[derive(Copy, Clone)]
struct S<T> { i:u8, t:T }
impl<T> S<T> {
fn unwrap(self) -> T {
self.t
}
}
#[derive(Copy, Clone, PartialEq, Debug)]
struct A((u32, u32));
#[derive(Copy, Clone, PartialEq, Debug)]
struct B(u64);
pub fn main() {
static Ca: S<A> = S { i: 0, t: A((13, 104)) };
static Cb: S<B> = S { i: 0, t: B(31337) };
assert_eq!(Ca.unwrap(), A((13, 104)));
assert_eq!(Cb.unwrap(), B(31337));
}