rustc_data_structures: Add implementation of 128 bit SipHash.

Author: michaelwoerister

src/libcore/hash/sip.rs

@@ -72,6 +72,7 @@ struct Hasher<S: Sip> {
 }
 
 #[derive(Debug, Clone, Copy)]
+#[repr(C)]
 struct State {
     // v0, v2 and v1, v3 show up in pairs in the algorithm,
     // and simd implementations of SipHash will use vectors

src/librustc_data_structures/lib.rs

@@ -54,6 +54,7 @@ pub mod graph;
 pub mod indexed_set;
 pub mod indexed_vec;
 pub mod obligation_forest;
+pub mod sip128;
 pub mod snapshot_map;
 pub mod snapshot_vec;
 pub mod stable_hasher;