Store hashes in special types so they aren't accidentally encoded as numbers

compiler/rustc_span/src/def_id.rs

@@ -1,12 +1,11 @@
 use crate::{HashStableContext, Symbol};
 use rustc_data_structures::fingerprint::Fingerprint;
-use rustc_data_structures::stable_hasher::{HashStable, StableHasher, ToStableHashKey};
+use rustc_data_structures::stable_hasher::{Hash64, HashStable, StableHasher, ToStableHashKey};
 use rustc_data_structures::unhash::Unhasher;
 use rustc_data_structures::AtomicRef;
 use rustc_index::vec::Idx;
 use rustc_macros::HashStable_Generic;
 use rustc_serialize::{Decodable, Decoder, Encodable, Encoder};
-use std::borrow::Borrow;
 use std::fmt;
 use std::hash::{BuildHasherDefault, Hash, Hasher};
 
@@ -105,20 +104,20 @@ impl DefPathHash {
     /// originates from.
     #[inline]
     pub fn stable_crate_id(&self) -> StableCrateId {
-        StableCrateId(self.0.as_value().0)
+        StableCrateId(self.0.split().0)
     }
 
     /// Returns the crate-local part of the [DefPathHash].
     ///
     /// Used for tests.
     #[inline]
-    pub fn local_hash(&self) -> u64 {
-        self.0.as_value().1
+    pub fn local_hash(&self) -> Hash64 {
+        self.0.split().1
     }
 
     /// Builds a new [DefPathHash] with the given [StableCrateId] and
     /// `local_hash`, where `local_hash` must be unique within its crate.
-    pub fn new(stable_crate_id: StableCrateId, local_hash: u64) -> DefPathHash {
+    pub fn new(stable_crate_id: StableCrateId, local_hash: Hash64) -> DefPathHash {
         DefPathHash(Fingerprint::new(stable_crate_id.0, local_hash))
     }
 }
@@ -129,13 +128,6 @@ impl Default for DefPathHash {
     }
 }
 
-impl Borrow<Fingerprint> for DefPathHash {
-    #[inline]
-    fn borrow(&self) -> &Fingerprint {
-        &self.0
-    }
-}
-
 /// A [`StableCrateId`] is a 64-bit hash of a crate name, together with all
 /// `-Cmetadata` arguments, and some other data. It is to [`CrateNum`] what [`DefPathHash`] is to
 /// [`DefId`]. It is stable across compilation sessions.
@@ -147,15 +139,11 @@ impl Borrow<Fingerprint> for DefPathHash {
 ///
 /// For more information on the possibility of hash collisions in rustc,
 /// see the discussion in [`DefId`].
-#[derive(Copy, Clone, Hash, PartialEq, Eq, PartialOrd, Ord, Debug)]
-#[derive(HashStable_Generic, Encodable, Decodable)]
-pub struct StableCrateId(pub(crate) u64);
+#[derive(Copy, Clone, PartialEq, Eq, PartialOrd, Ord, Debug)]
+#[derive(Hash, HashStable_Generic, Encodable, Decodable)]
+pub struct StableCrateId(pub(crate) Hash64);
 
 impl StableCrateId {
-    pub fn to_u64(self) -> u64 {
-        self.0
-    }
-
     /// Computes the stable ID for a crate with the given name and
     /// `-Cmetadata` arguments.
     pub fn new(crate_name: Symbol, is_exe: bool, mut metadata: Vec<String>) -> StableCrateId {
@@ -197,6 +185,16 @@ impl StableCrateId {
 
         StableCrateId(hasher.finish())
     }
+
+    pub fn as_u64(self) -> u64 {
+        self.0.as_u64()
+    }
+}
+
+impl fmt::LowerHex for StableCrateId {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        fmt::LowerHex::fmt(&self.0, f)
+    }
 }
 
 rustc_index::newtype_index! {

compiler/rustc_span/src/hygiene.rs

@@ -33,7 +33,7 @@ use crate::def_id::{CrateNum, DefId, StableCrateId, CRATE_DEF_ID, LOCAL_CRATE};
 use rustc_data_structures::fingerprint::Fingerprint;
 use rustc_data_structures::fx::{FxHashMap, FxHashSet};
 use rustc_data_structures::stable_hasher::HashingControls;
-use rustc_data_structures::stable_hasher::{HashStable, StableHasher};
+use rustc_data_structures::stable_hasher::{Hash64, HashStable, StableHasher};
 use rustc_data_structures::sync::{Lock, Lrc};
 use rustc_data_structures::unhash::UnhashMap;
 use rustc_index::vec::IndexVec;
@@ -123,15 +123,15 @@ impl ExpnHash {
     /// originates from.
     #[inline]
     pub fn stable_crate_id(self) -> StableCrateId {
-        StableCrateId(self.0.as_value().0)
+        StableCrateId(self.0.split().0)
     }
 
     /// Returns the crate-local part of the [ExpnHash].
     ///
     /// Used for tests.
     #[inline]
-    pub fn local_hash(self) -> u64 {
-        self.0.as_value().1
+    pub fn local_hash(self) -> Hash64 {
+        self.0.split().1
     }
 
     #[inline]
@@ -141,7 +141,7 @@ impl ExpnHash {
 
     /// Builds a new [ExpnHash] with the given [StableCrateId] and
     /// `local_hash`, where `local_hash` must be unique within its crate.
-    fn new(stable_crate_id: StableCrateId, local_hash: u64) -> ExpnHash {
+    fn new(stable_crate_id: StableCrateId, local_hash: Hash64) -> ExpnHash {
         ExpnHash(Fingerprint::new(stable_crate_id.0, local_hash))
     }
 }
@@ -350,7 +350,7 @@ pub struct HygieneData {
     /// would have collisions without a disambiguator.
     /// The keys of this map are always computed with `ExpnData.disambiguator`
     /// set to 0.
-    expn_data_disambiguators: FxHashMap<u64, u32>,
+    expn_data_disambiguators: FxHashMap<Hash64, u32>,
 }
 
 impl HygieneData {
@@ -1040,7 +1040,7 @@ impl ExpnData {
     }
 
     #[inline]
-    fn hash_expn(&self, ctx: &mut impl HashStableContext) -> u64 {
+    fn hash_expn(&self, ctx: &mut impl HashStableContext) -> Hash64 {
         let mut hasher = StableHasher::new();
         self.hash_stable(ctx, &mut hasher);
         hasher.finish()

compiler/rustc_span/src/lib.rs

@@ -59,7 +59,7 @@ pub mod fatal_error;
 
 pub mod profiling;
 
-use rustc_data_structures::stable_hasher::{HashStable, StableHasher};
+use rustc_data_structures::stable_hasher::{Hash128, Hash64, HashStable, StableHasher};
 use rustc_data_structures::sync::{Lock, Lrc};
 
 use std::borrow::Cow;
@@ -282,22 +282,22 @@ impl RealFileName {
 pub enum FileName {
     Real(RealFileName),
     /// Call to `quote!`.
-    QuoteExpansion(u64),
+    QuoteExpansion(Hash64),
     /// Command line.
-    Anon(u64),
+    Anon(Hash64),
     /// Hack in `src/librustc_ast/parse.rs`.
     // FIXME(jseyfried)
-    MacroExpansion(u64),
-    ProcMacroSourceCode(u64),
+    MacroExpansion(Hash64),
+    ProcMacroSourceCode(Hash64),
     /// Strings provided as `--cfg [cfgspec]` stored in a `crate_cfg`.
-    CfgSpec(u64),
+    CfgSpec(Hash64),
     /// Strings provided as crate attributes in the CLI.
-    CliCrateAttr(u64),
+    CliCrateAttr(Hash64),
     /// Custom sources for explicit parser calls from plugins and drivers.
     Custom(String),
     DocTest(PathBuf, isize),
     /// Post-substitution inline assembly from LLVM.
-    InlineAsm(u64),
+    InlineAsm(Hash64),
 }
 
 impl From<PathBuf> for FileName {
@@ -1343,7 +1343,7 @@ pub struct SourceFile {
     /// Locations of characters removed during normalization.
     pub normalized_pos: Vec<NormalizedPos>,
     /// A hash of the filename, used for speeding up hashing in incremental compilation.
-    pub name_hash: u128,
+    pub name_hash: Hash128,
     /// Indicates which crate this `SourceFile` was imported from.
     pub cnum: CrateNum,
 }
@@ -1472,7 +1472,7 @@ impl<D: Decoder> Decodable<D> for SourceFile {
         };
         let multibyte_chars: Vec<MultiByteChar> = Decodable::decode(d);
         let non_narrow_chars: Vec<NonNarrowChar> = Decodable::decode(d);
-        let name_hash: u128 = Decodable::decode(d);
+        let name_hash = Decodable::decode(d);
         let normalized_pos: Vec<NormalizedPos> = Decodable::decode(d);
         let cnum: CrateNum = Decodable::decode(d);
         SourceFile {
@@ -1514,7 +1514,7 @@ impl SourceFile {
         let name_hash = {
             let mut hasher: StableHasher = StableHasher::new();
             name.hash(&mut hasher);
-            hasher.finish::<u128>()
+            hasher.finish()
         };
         let end_pos = start_pos.to_usize() + src.len();
         assert!(end_pos <= u32::MAX as usize);

compiler/rustc_span/src/source_map.rs

@@ -13,7 +13,7 @@ pub use crate::hygiene::{ExpnData, ExpnKind};
 pub use crate::*;
 
 use rustc_data_structures::fx::FxHashMap;
-use rustc_data_structures::stable_hasher::StableHasher;
+use rustc_data_structures::stable_hasher::{Hash128, Hash64, StableHasher};
 use rustc_data_structures::sync::{AtomicU32, Lrc, MappedReadGuard, ReadGuard, RwLock};
 use std::cmp;
 use std::hash::Hash;
@@ -138,7 +138,7 @@ impl FileLoader for RealFileLoader {
 pub struct StableSourceFileId {
     /// A hash of the source file's [`FileName`]. This is hash so that it's size
     /// is more predictable than if we included the actual [`FileName`] value.
-    pub file_name_hash: u64,
+    pub file_name_hash: Hash64,
 
     /// The [`CrateNum`] of the crate this source file was originally parsed for.
     /// We cannot include this information in the hash because at the time
@@ -331,7 +331,7 @@ impl SourceMap {
         &self,
         filename: FileName,
         src_hash: SourceFileHash,
-        name_hash: u128,
+        name_hash: Hash128,
         source_len: usize,
         cnum: CrateNum,
         file_local_lines: Lock<SourceFileLines>,

compiler/rustc_span/src/tests.rs

@@ -3,8 +3,12 @@ use super::*;
 #[test]
 fn test_lookup_line() {
     let source = "abcdefghijklm\nabcdefghij\n...".to_owned();
-    let sf =
-        SourceFile::new(FileName::Anon(0), source, BytePos(3), SourceFileHashAlgorithm::Sha256);
+    let sf = SourceFile::new(
+        FileName::Anon(Hash64::ZERO),
+        source,
+        BytePos(3),
+        SourceFileHashAlgorithm::Sha256,
+    );
     sf.lines(|lines| assert_eq!(lines, &[BytePos(3), BytePos(17), BytePos(28)]));
 
     assert_eq!(sf.lookup_line(BytePos(0)), None);