Move hashes from rustc_data_structure to rustc_hashes so they can be shared with rust-analyzer

compiler/rustc_serialize/Cargo.toml

@@ -6,6 +6,7 @@ edition = "2021"
 [dependencies]
 # tidy-alphabetical-start
 indexmap = "2.0.0"
+rustc_hashes = { path = "../rustc_hashes" }
 smallvec = { version = "1.8.1", features = ["union", "may_dangle"] }
 thin-vec = "0.2.12"
 # tidy-alphabetical-end

compiler/rustc_serialize/src/serialize.rs

@@ -10,6 +10,7 @@ use std::path;
 use std::rc::Rc;
 use std::sync::Arc;
 
+use rustc_hashes::{Hash64, Hash128};
 use smallvec::{Array, SmallVec};
 use thin_vec::ThinVec;
 
@@ -716,3 +717,31 @@ impl<D: Decoder, T: Decodable<D>> Decodable<D> for Arc<[T]> {
         vec.into()
     }
 }
+
+impl<S: Encoder> Encodable<S> for Hash64 {
+    #[inline]
+    fn encode(&self, s: &mut S) {
+        s.emit_raw_bytes(&self.as_u64().to_le_bytes());
+    }
+}
+
+impl<S: Encoder> Encodable<S> for Hash128 {
+    #[inline]
+    fn encode(&self, s: &mut S) {
+        s.emit_raw_bytes(&self.as_u128().to_le_bytes());
+    }
+}
+
+impl<D: Decoder> Decodable<D> for Hash64 {
+    #[inline]
+    fn decode(d: &mut D) -> Self {
+        Self::new(u64::from_le_bytes(d.read_raw_bytes(8).try_into().unwrap()))
+    }
+}
+
+impl<D: Decoder> Decodable<D> for Hash128 {
+    #[inline]
+    fn decode(d: &mut D) -> Self {
+        Self::new(u128::from_le_bytes(d.read_raw_bytes(16).try_into().unwrap()))
+    }
+}