Add dist step for Enzyme

src/bootstrap/src/core/build_steps/dist.rs

@@ -2717,6 +2717,55 @@ impl Step for LlvmBitcodeLinker {
     }
 }
 
+/// Distributes the `enzyme` library so that it can be used by a compiler whose host
+/// is `target`.
+#[derive(Debug, Clone, Hash, PartialEq, Eq)]
+pub struct Enzyme {
+    /// Enzyme will by usable by rustc on this host.
+    pub target: TargetSelection,
+}
+
+impl Step for Enzyme {
+    type Output = Option<GeneratedTarball>;
+    const IS_HOST: bool = true;
+
+    fn should_run(run: ShouldRun<'_>) -> ShouldRun<'_> {
+        run.alias("enzyme")
+    }
+
+    fn is_default_step(builder: &Builder<'_>) -> bool {
+        builder.config.llvm_enzyme
+    }
+
+    fn make_run(run: RunConfig<'_>) {
+        run.builder.ensure(Enzyme { target: run.target });
+    }
+
+    fn run(self, builder: &Builder<'_>) -> Option<GeneratedTarball> {
+        // This prevents Enzyme from being built for "dist"
+        // or "install" on the stable/beta channels. It is not yet stable and
+        // should not be included.
+        if !builder.build.unstable_features() {
+            return None;
+        }
+
+        let target = self.target;
+
+        let enzyme = builder.ensure(llvm::Enzyme { target });
+
+        let target_libdir = format!("lib/rustlib/{}/lib", target.triple);
+
+        // Prepare the image directory
+        let mut tarball = Tarball::new(builder, "enzyme", &target.triple);
+        tarball.set_overlay(OverlayKind::Enzyme);
+        tarball.is_preview(true);
+
+        tarball.add_file(enzyme.enzyme_path(), target_libdir, FileType::NativeLibrary);
+
+        Some(tarball.generate())
+    }
+}
+
 /// Tarball intended for internal consumption to ease rustc/std development.
 ///
 /// Should not be considered stable by end users.

src/bootstrap/src/core/builder/mod.rs

@@ -980,6 +980,7 @@ impl<'a> Builder<'a> {
                 dist::LlvmTools,
                 dist::LlvmBitcodeLinker,
                 dist::RustDev,
+                dist::Enzyme,
                 dist::Bootstrap,
                 dist::Extended,
                 // It seems that PlainSourceTarball somehow changes how some of the tools

src/bootstrap/src/utils/tarball.rs

@@ -28,6 +28,7 @@ pub(crate) enum OverlayKind {
     RustcCodegenGcc,
     Gcc,
     LlvmBitcodeLinker,
+    Enzyme,
 }
 
 impl OverlayKind {
@@ -37,6 +38,7 @@ impl OverlayKind {
             OverlayKind::Llvm => {
                 &["src/llvm-project/llvm/LICENSE.TXT", "src/llvm-project/llvm/README.txt"]
             }
+            OverlayKind::Enzyme => &["src/tools/enzyme/LICENSE", "src/tools/enzyme/Readme.md"],
             OverlayKind::Cargo => &[
                 "src/tools/cargo/README.md",
                 "src/tools/cargo/LICENSE-MIT",
@@ -111,6 +113,7 @@ impl OverlayKind {
             OverlayKind::RustcCodegenGcc => builder.rust_version(),
             OverlayKind::LlvmBitcodeLinker => builder.rust_version(),
             OverlayKind::Gcc => builder.rust_version(),
+            OverlayKind::Enzyme => builder.rust_version(),
         }
     }
 }