Auto merge of rust-lang#127809 - Urgau:blake2-stable-hash, r=<try>

[perf] Change stable hasher to Blake2s

Based on rust-lang/rustc-stable-hash@main...Urgau:rustc-stable-hash:blake2

With inputs from https://jszym.com/blog/short_input_hash/ and rust-lang#127754.

cc `@michaelwoerister` `@Kobzol`
r? ghost

Author: bors

Cargo.lock

@@ -237,6 +237,12 @@ dependencies = [
  "object 0.35.0",
 ]
 
+[[package]]
+name = "arrayref"
+version = "0.3.7"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "6b4930d2cb77ce62f89ee5d5289b4ac049559b1c45539271f5ed4fdc7db34545"
+
 [[package]]
 name = "arrayvec"
 version = "0.7.4"
@@ -356,6 +362,17 @@ version = "2.5.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "cf4b9d6a944f767f8e5e0db018570623c85f3d925ac718db4e06d0187adb21c1"
 
+[[package]]
+name = "blake2s_simd"
+version = "1.0.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "94230421e395b9920d23df13ea5d77a20e1725331f90fbbf6df6040b33f756ae"
+dependencies = [
+ "arrayref",
+ "arrayvec",
+ "constant_time_eq",
+]
+
 [[package]]
 name = "block-buffer"
 version = "0.10.4"
@@ -842,6 +859,12 @@ dependencies = [
  "windows-sys 0.52.0",
 ]
 
+[[package]]
+name = "constant_time_eq"
+version = "0.3.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "f7144d30dcf0fafbce74250a3963025d8d52177934239851c917d29f1df280c2"
+
 [[package]]
 name = "core"
 version = "0.0.0"
@@ -3544,8 +3567,10 @@ checksum = "5be1bdc7edf596692617627bbfeaba522131b18e06ca4df2b6b689e3c5d5ce84"
 [[package]]
 name = "rustc-stable-hash"
 version = "0.1.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "e5c9f15eec8235d7cb775ee6f81891db79b98fd54ba1ad8fae565b88ef1ae4e2"
+source = "git+https://github.com/Urgau/rustc-stable-hash.git?rev=4f8c5a9#4f8c5a993536388a22fba12d0be76837dcd52017"
+dependencies = [
+ "blake2s_simd",
+]
 
 [[package]]
 name = "rustc-std-workspace-alloc"

compiler/rustc_data_structures/Cargo.toml

@@ -15,7 +15,7 @@ jobserver_crate = { version = "0.1.28", package = "jobserver" }
 measureme = "11"
 rustc-hash = "1.1.0"
 rustc-rayon = { version = "0.5.0", optional = true }
-rustc-stable-hash = { version = "0.1.0", features = ["nightly"] }
+rustc-stable-hash = { git = "https://github.com/Urgau/rustc-stable-hash.git", rev = "4f8c5a9", features = ["blake2", "nightly"] }
 rustc_arena = { path = "../rustc_arena" }
 rustc_graphviz = { path = "../rustc_graphviz" }
 rustc_index = { path = "../rustc_index", package = "rustc_index" }

compiler/rustc_data_structures/src/fingerprint.rs

@@ -158,8 +158,15 @@ impl FromStableHash for Fingerprint {
     type Hash = StableHasherHash;
 
     #[inline]
-    fn from(StableHasherHash([_0, _1]): Self::Hash) -> Self {
-        Fingerprint(_0, _1)
+    fn from(StableHasherHash(bytes): Self::Hash) -> Self {
+        let p0 = u64::from_le_bytes(bytes[0..8].try_into().unwrap());
+        let p1 = u64::from_le_bytes(bytes[8..16].try_into().unwrap());
+        let p2 = u64::from_le_bytes(bytes[16..24].try_into().unwrap());
+        let p3 = u64::from_le_bytes(bytes[24..32].try_into().unwrap());
+
+        // See https://stackoverflow.com/a/27952689 on why this function is
+        // implemented this way.
+        Fingerprint(p0.wrapping_mul(3).wrapping_add(p1), p2.wrapping_mul(3).wrapping_add(p3))
     }
 }
 

compiler/rustc_data_structures/src/hashes.rs

@@ -60,8 +60,19 @@ impl FromStableHash for Hash64 {
     type Hash = StableHasherHash;
 
     #[inline]
-    fn from(StableHasherHash([_0, __1]): Self::Hash) -> Self {
-        Self { inner: _0 }
+    fn from(StableHasherHash(bytes): Self::Hash) -> Self {
+        let p0 = u64::from_le_bytes(bytes[0..8].try_into().unwrap());
+        let p1 = u64::from_le_bytes(bytes[8..16].try_into().unwrap());
+        let p2 = u64::from_le_bytes(bytes[16..24].try_into().unwrap());
+        let p3 = u64::from_le_bytes(bytes[24..32].try_into().unwrap());
+
+        // See https://stackoverflow.com/a/27952689 on why this function is
+        // implemented this way.
+        let m0 = p0.wrapping_mul(3).wrapping_add(p1);
+        let m1 = p2.wrapping_mul(3).wrapping_add(p3);
+        let h = m0.wrapping_mul(3).wrapping_add(m1);
+
+        Self { inner: h }
     }
 }
 
@@ -127,8 +138,18 @@ impl FromStableHash for Hash128 {
     type Hash = StableHasherHash;
 
     #[inline]
-    fn from(StableHasherHash([_0, _1]): Self::Hash) -> Self {
-        Self { inner: u128::from(_0) | (u128::from(_1) << 64) }
+    fn from(StableHasherHash(bytes): Self::Hash) -> Self {
+        let p0 = u64::from_le_bytes(bytes[0..8].try_into().unwrap());
+        let p1 = u64::from_le_bytes(bytes[8..16].try_into().unwrap());
+        let p2 = u64::from_le_bytes(bytes[16..24].try_into().unwrap());
+        let p3 = u64::from_le_bytes(bytes[24..32].try_into().unwrap());
+
+        // See https://stackoverflow.com/a/27952689 on why this function is
+        // implemented this way.
+        let upper = p0.wrapping_mul(3).wrapping_add(p1);
+        let lower = p2.wrapping_mul(3).wrapping_add(p3);
+
+        Self { inner: u128::from(lower) | (u128::from(upper) << 64) }
     }
 }
 

compiler/rustc_data_structures/src/stable_hasher.rs

@@ -11,9 +11,9 @@ mod tests;
 
 pub use crate::hashes::{Hash128, Hash64};
 
+pub use rustc_stable_hash::hashers::Blake2s256Hash as StableHasherHash;
+pub use rustc_stable_hash::hashers::StableBlake2sHasher256 as StableHasher;
 pub use rustc_stable_hash::FromStableHash;
-pub use rustc_stable_hash::SipHasher128Hash as StableHasherHash;
-pub use rustc_stable_hash::StableSipHasher128 as StableHasher;
 
 /// Something that implements `HashStable<CTX>` can be hashed in a way that is
 /// stable across multiple compilation sessions.

src/tools/tidy/src/deps.rs

@@ -21,6 +21,7 @@ const LICENSES: &[&str] = &[
     "Apache-2.0",
     "Apache-2.0/MIT",
     "BSD-2-Clause OR Apache-2.0 OR MIT",                   // zerocopy
+    "CC0-1.0 OR MIT-0 OR Apache-2.0",                      // contant_time_eq
     "ISC",
     "MIT / Apache-2.0",
     "MIT OR Apache-2.0 OR LGPL-2.1-or-later",              // r-efi, r-efi-alloc
@@ -83,6 +84,7 @@ pub(crate) const WORKSPACES: &[(&str, ExceptionList, Option<(&[&str], &[&str])>)
 const EXCEPTIONS: ExceptionList = &[
     // tidy-alphabetical-start
     ("ar_archive_writer", "Apache-2.0 WITH LLVM-exception"), // rustc
+    ("arrayref", "BSD-2-Clause"),                            // rustc
     ("colored", "MPL-2.0"),                                  // rustfmt
     ("dissimilar", "Apache-2.0"),                            // rustdoc, rustc_lexer (few tests) via expect-test, (dev deps)
     ("fluent-langneg", "Apache-2.0"),                        // rustc (fluent translations)
@@ -237,15 +239,18 @@ const PERMITTED_RUSTC_DEPENDENCIES: &[&str] = &[
     "annotate-snippets",
     "anstyle",
     "ar_archive_writer",
+    "arrayref",
     "arrayvec",
     "autocfg",
     "bitflags",
+    "blake2s_simd",
     "block-buffer",
     "byteorder", // via ruzstd in object in thorin-dwp
     "cc",
     "cfg-if",
     "cfg_aliases",
     "compiler_builtins",
+    "constant_time_eq",
     "cpufeatures",
     "crc32fast",
     "crossbeam-channel",

src/tools/tidy/src/extdeps.rs

@@ -9,6 +9,8 @@ const ALLOWED_SOURCES: &[&str] = &[
     r#""registry+https://github.com/rust-lang/crates.io-index""#,
     // This is `rust_team_data` used by `site` in src/tools/rustc-perf,
     r#""git+https://github.com/rust-lang/team#a5260e76d3aa894c64c56e6ddc8545b9a98043ec""#,
+    // WIP Blake2 in rustc-stable-hash
+    r#""git+https://github.com/Urgau/rustc-stable-hash.git?rev=4f8c5a9#4f8c5a993536388a22fba12d0be76837dcd52017""#,
 ];
 
 /// Checks for external package sources. `root` is the path to the directory that contains the