Unrolled build for rust-lang#135585

Rollup merge of rust-lang#135585 - onur-ozkan:135554, r=Kobzol

resolve symlinks of LLVM tool binaries before copying them

There is a chance that these tools are being installed from an external LLVM and we have no control over them. If any of these tools use symlinks, they will fail during tarball distribution. This change makes copying process to resolve symlinks just before placing them into the destination path.

Fixes rust-lang#135554

src/bootstrap/src/core/build_steps/compile.rs

@@ -1777,7 +1777,13 @@ impl Step for Assemble {
                     // When using `download-ci-llvm`, some of the tools
                     // may not exist, so skip trying to copy them.
                     if src_path.exists() {
-                        builder.copy_link(&src_path, &libdir_bin.join(&tool_exe));
+                        // There is a chance that these tools are being installed from an external LLVM.
+                        // Use `Builder::resolve_symlink_and_copy` instead of `Builder::copy_link` to ensure
+                        // we are copying the original file not the symlinked path, which causes issues for
+                        // tarball distribution.
+                        //
+                        // See /~https://github.com/rust-lang/rust/issues/135554.
+                        builder.resolve_symlink_and_copy(&src_path, &libdir_bin.join(&tool_exe));
                     }
                 }
             }

src/bootstrap/src/lib.rs

@@ -1633,6 +1633,14 @@ Executed at: {executed_at}"#,
         paths
     }
 
+    /// Copies a file from `src` to `dst`.
+    ///
+    /// If `src` is a symlink, `src` will be resolved to the actual path
+    /// and copied to `dst` instead of the symlink itself.
+    pub fn resolve_symlink_and_copy(&self, src: &Path, dst: &Path) {
+        self.copy_link_internal(src, dst, true);
+    }
+
     /// Links a file from `src` to `dst`.
     /// Attempts to use hard links if possible, falling back to copying.
     /// You can neither rely on this being a copy nor it being a link,