Rollup merge of #137095 - saethlin:use-hash64-for-hashes, r=workingjubilee

Replace some u64 hashes with Hash64

I introduced the Hash64 and Hash128 types in rust-lang/rust#110083, essentially as a mechanism to prevent hashes from landing in our leb128 encoding paths. If you just have a u64 or u128 field in a struct then derive Encodable/Decodable, that number gets leb128 encoding. So if you need to store a hash or some other value which behaves very close to a hash, don't store it as a u64.

This reverts part of rust-lang/rust#117603, which turned an encoded Hash64 into a u64.

Based on rust-lang/rust#110083, I don't expect this to be perf-sensitive on its own, though I expect that it may help stabilize some of the small rmeta size fluctuations we currently see in perf reports.

Author: matthiaskrgr

crates/hir-def/src/data/adt.rs

@@ -9,6 +9,7 @@ use hir_expand::name::Name;
 use intern::sym;
 use la_arena::Arena;
 use rustc_abi::{Align, Integer, IntegerType, ReprFlags, ReprOptions};
+use rustc_hashes::Hash64;
 use triomphe::Arc;
 use tt::iter::TtElement;
 
@@ -172,7 +173,7 @@ fn parse_repr_tt(tt: &TopSubtree) -> Option<ReprOptions> {
         }
     }
 
-    Some(ReprOptions { int, align: max_align, pack: min_pack, flags, field_shuffle_seed: 0 })
+    Some(ReprOptions { int, align: max_align, pack: min_pack, flags, field_shuffle_seed: Hash64::ZERO })
 }
 
 impl StructData {

crates/hir-def/src/lib.rs

@@ -18,9 +18,15 @@ extern crate ra_ap_rustc_parse_format as rustc_parse_format;
 #[cfg(feature = "in-rust-tree")]
 extern crate rustc_abi;
 
+#[cfg(feature = "in-rust-tree")]
+extern crate rustc_hashes;
+
 #[cfg(not(feature = "in-rust-tree"))]
 extern crate ra_ap_rustc_abi as rustc_abi;
 
+#[cfg(not(feature = "in-rust-tree"))]
+extern crate ra_ap_rustc_hashes as rustc_hashes;
+
 pub mod db;
 
 pub mod attr;

crates/hir-ty/src/layout.rs

@@ -15,6 +15,7 @@ use hir_def::{
 use la_arena::{Idx, RawIdx};
 use rustc_abi::AddressSpace;
 use rustc_index::{IndexSlice, IndexVec};
+use rustc_hashes::Hash64;
 
 use triomphe::Arc;
 
@@ -197,7 +198,7 @@ fn layout_of_simd_ty(
         align,
         max_repr_align: None,
         unadjusted_abi_align: align.abi,
-        randomization_seed: 0,
+        randomization_seed: Hash64::ZERO,
     }))
 }
 
@@ -314,7 +315,7 @@ pub fn layout_of_ty_query(
                 size,
                 max_repr_align: None,
                 unadjusted_abi_align: element.align.abi,
-                randomization_seed: 0,
+                randomization_seed: Hash64::ZERO,
             }
         }
         TyKind::Slice(element) => {
@@ -328,7 +329,7 @@ pub fn layout_of_ty_query(
                 size: Size::ZERO,
                 max_repr_align: None,
                 unadjusted_abi_align: element.align.abi,
-                randomization_seed: 0,
+                randomization_seed: Hash64::ZERO,
             }
         }
         TyKind::Str => Layout {
@@ -340,7 +341,7 @@ pub fn layout_of_ty_query(
             size: Size::ZERO,
             max_repr_align: None,
             unadjusted_abi_align: dl.i8_align.abi,
-            randomization_seed: 0,
+            randomization_seed: Hash64::ZERO,
         },
         // Potentially-wide pointers.
         TyKind::Ref(_, _, pointee) | TyKind::Raw(_, pointee) => {

crates/hir-ty/src/lib.rs

@@ -12,6 +12,9 @@ extern crate ra_ap_rustc_index as rustc_index;
 #[cfg(feature = "in-rust-tree")]
 extern crate rustc_abi;
 
+#[cfg(feature = "in-rust-tree")]
+extern crate rustc_hashes;
+
 #[cfg(not(feature = "in-rust-tree"))]
 extern crate ra_ap_rustc_abi as rustc_abi;
 
@@ -21,6 +24,9 @@ extern crate rustc_pattern_analysis;
 #[cfg(not(feature = "in-rust-tree"))]
 extern crate ra_ap_rustc_pattern_analysis as rustc_pattern_analysis;
 
+#[cfg(not(feature = "in-rust-tree"))]
+extern crate ra_ap_rustc_hashes as rustc_hashes;
+
 mod builder;
 mod chalk_db;
 mod chalk_ext;