Link LLVM dynamically on aarch64-apple-darwin dist and copy libLLVM with a versioned name

compiler/rustc_llvm/build.rs

@@ -402,6 +402,16 @@ fn main() {
             continue;
         }
 
+        // On apple-darwin, llvm-config reports the versioned shared library name such as LLVM-22-..., but
+        // the distributed toolchain ships libLLVM.dylib. Normalize the link name here.
+        let name =
+            if target.contains("apple-darwin") && llvm_kind == "dylib" && name.starts_with("LLVM-")
+            {
+                "LLVM"
+            } else {
+                name
+            };
+
         let kind = if name.starts_with("LLVM") {
             llvm_kind
         } else if is_static {

compiler/rustc_metadata/src/native_libs.rs

@@ -62,12 +62,15 @@ pub fn walk_native_lib_search_dirs<R>(
         f(&sess.target_tlib_path.dir.join("self-contained"), false)?;
     }
 
+    let has_shared_llvm_apple_darwin =
+        sess.target.is_like_darwin && sess.target_tlib_path.dir.join("libLLVM.dylib").exists();
+
     // Toolchains for some targets may ship `libunwind.a`, but place it into the main sysroot
     // library directory instead of the self-contained directories.
     // Sanitizer libraries have the same issue and are also linked by name on Apple targets.
     // The targets here should be in sync with `copy_third_party_objects` in bootstrap.
-    // Finally there is shared LLVM library, which unlike compiler libraries, is linked by the name,
-    // therefore requiring the search path for the linker.
+    // On Apple targets, shared LLVM is linked by name, so when `libLLVM.dylib` is
+    // present in the target libdir, add that directory to the linker search path.
     // FIXME: implement `-Clink-self-contained=+/-unwind,+/-sanitizers`, move the shipped libunwind
     // and sanitizers to self-contained directory, and stop adding this search path.
     // FIXME: On AIX this also has the side-effect of making the list of library search paths
@@ -77,7 +80,8 @@ pub fn walk_native_lib_search_dirs<R>(
         || sess.target.os == Os::Linux
         || sess.target.os == Os::Fuchsia
         || sess.target.is_like_aix
-        || sess.target.is_like_darwin && !sess.sanitizers().is_empty()
+        || sess.target.is_like_darwin
+            && (!sess.sanitizers().is_empty() || has_shared_llvm_apple_darwin)
         || sess.target.os == Os::Windows
             && sess.target.env == Env::Gnu
             && sess.target.cfg_abi == CfgAbi::Llvm

src/bootstrap/download-ci-llvm-stamp

@@ -1,4 +1,4 @@
 Change this file to make users of the `download-ci-llvm` configuration download
 a new version of LLVM from CI, even if the LLVM submodule hasn’t changed.
 
-Last change is for: https://github.com/rust-lang/rust/pull/154485
+Last change is for: test

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

@@ -2495,6 +2495,25 @@ fn maybe_install_llvm(
         let llvm_dylib_path = src_libdir.join("libLLVM.dylib");
         if llvm_dylib_path.exists() {
             builder.install(&llvm_dylib_path, dst_libdir, FileType::NativeLibrary);
+
+            if install_symlink && let Some(llvm_config) = builder.llvm_config(target) {
+                let major = llvm::get_llvm_version_major(builder, &llvm_config);
+                let llvm_version_suffix = llvm::get_llvm_version_suffix(builder);
+                match llvm_version_suffix {
+                    Some(suffix) => {
+                        t!(fs::copy(
+                            dst_libdir.join("libLLVM.dylib"),
+                            dst_libdir.join(format!("libLLVM-{major}{suffix}.dylib"))
+                        ));
+                    }
+                    None => {
+                        t!(fs::copy(
+                            dst_libdir.join("libLLVM.dylib"),
+                            dst_libdir.join(format!("libLLVM-{major}.dylib"))
+                        ));
+                    }
+                }
+            };
         }
         !builder.config.dry_run()
     } else if let llvm::LlvmBuildStatus::AlreadyBuilt(llvm::LlvmResult {

src/bootstrap/src/core/build_steps/llvm.rs

@@ -524,17 +524,7 @@ impl Step for Llvm {
             }
         }
 
-        let llvm_version_suffix = if let Some(ref suffix) = builder.config.llvm_version_suffix {
-            // Allow version-suffix="" to not define a version suffix at all.
-            if !suffix.is_empty() { Some(suffix.to_string()) } else { None }
-        } else if builder.config.channel == "dev" {
-            // Changes to a version suffix require a complete rebuild of the LLVM.
-            // To avoid rebuilds during a time of version bump, don't include rustc
-            // release number on the dev channel.
-            Some("-rust-dev".to_string())
-        } else {
-            Some(format!("-rust-{}-{}", builder.version, builder.config.channel))
-        };
+        let llvm_version_suffix = get_llvm_version_suffix(builder);
         if let Some(ref suffix) = llvm_version_suffix {
             cfg.define("LLVM_VERSION_SUFFIX", suffix);
         }
@@ -623,6 +613,20 @@ pub fn get_llvm_version_major(builder: &Builder<'_>, llvm_config: &Path) -> u8 {
     major_str.parse().unwrap()
 }
 
+pub fn get_llvm_version_suffix(builder: &Builder<'_>) -> Option<String> {
+    if let Some(ref suffix) = builder.config.llvm_version_suffix {
+        // Allow version-suffix="" to not define a version suffix at all.
+        if !suffix.is_empty() { Some(suffix.to_string()) } else { None }
+    } else if builder.config.channel == "dev" {
+        // Changes to a version suffix require a complete rebuild of the LLVM.
+        // To avoid rebuilds during a time of version bump, don't include rustc
+        // release number on the dev channel.
+        Some("-rust-dev".to_string())
+    } else {
+        Some(format!("-rust-{}-{}", builder.version, builder.config.channel))
+    }
+}
+
 fn check_llvm_version(builder: &Builder<'_>, llvm_config: &Path) {
     if builder.config.dry_run() {
         return;

src/ci/github-actions/jobs.yml

@@ -518,6 +518,7 @@ auto:
         --enable-sanitizers
         --enable-profiler
         --set rust.jemalloc
+        --set llvm.link-shared=true
         --set rust.lto=thin
         --set rust.codegen-units=1
       # Aarch64 tooling only needs to support macOS 11.0 and up as nothing else