bootstrap: copy llvm-dwp to sysroot

`llvm-dwp` is required for linking the DWARF objects into DWARF packages
when using Split DWARF, especially given that rustc produces multiple
DWARF objects (one for each codegen unit).

Signed-off-by: David Wood <david@davidtw.co>

src/bootstrap/compile.rs

@@ -969,15 +969,25 @@ impl Step for Assemble {
 
         copy_codegen_backends_to_sysroot(builder, build_compiler, target_compiler);
 
+        // We prepend this bin directory to the user PATH when linking Rust binaries. To
+        // avoid shadowing the system LLD we rename the LLD we provide to `rust-lld`.
         let libdir = builder.sysroot_libdir(target_compiler, target_compiler.host);
+        let libdir_bin = libdir.parent().unwrap().join("bin");
+        t!(fs::create_dir_all(&libdir_bin));
+
         if let Some(lld_install) = lld_install {
             let src_exe = exe("lld", target_compiler.host);
             let dst_exe = exe("rust-lld", target_compiler.host);
-            // we prepend this bin directory to the user PATH when linking Rust binaries. To
-            // avoid shadowing the system LLD we rename the LLD we provide to `rust-lld`.
-            let dst = libdir.parent().unwrap().join("bin");
-            t!(fs::create_dir_all(&dst));
-            builder.copy(&lld_install.join("bin").join(&src_exe), &dst.join(&dst_exe));
+            builder.copy(&lld_install.join("bin").join(&src_exe), &libdir_bin.join(&dst_exe));
+        }
+
+        // Similarly, copy `llvm-dwp` into libdir for Split DWARF.
+        {
+            let src_exe = exe("llvm-dwp", target_compiler.host);
+            let dst_exe = exe("rust-llvm-dwp", target_compiler.host);
+            let llvm_config_bin = builder.ensure(native::Llvm { target: target_compiler.host });
+            let llvm_bin_dir = llvm_config_bin.parent().unwrap();
+            builder.copy(&llvm_bin_dir.join(&src_exe), &libdir_bin.join(&dst_exe));
         }
 
         // Ensure that `libLLVM.so` ends up in the newly build compiler directory,

src/bootstrap/dist.rs

@@ -523,17 +523,20 @@ impl Step for Rustc {
             // component for now.
             maybe_install_llvm_runtime(builder, host, image);
 
+            let src_dir = builder.sysroot_libdir(compiler, host).parent().unwrap().join("bin");
+            let dst_dir = image.join("lib/rustlib").join(&*host.triple).join("bin");
+            t!(fs::create_dir_all(&dst_dir));
+
             // Copy over lld if it's there
             if builder.config.lld_enabled {
                 let exe = exe("rust-lld", compiler.host);
-                let src =
-                    builder.sysroot_libdir(compiler, host).parent().unwrap().join("bin").join(&exe);
-                // for the rationale about this rename check `compile::copy_lld_to_sysroot`
-                let dst = image.join("lib/rustlib").join(&*host.triple).join("bin").join(&exe);
-                t!(fs::create_dir_all(&dst.parent().unwrap()));
-                builder.copy(&src, &dst);
+                builder.copy(&src_dir.join(&exe), &dst_dir.join(&exe));
             }
 
+            // Copy over llvm-dwp if it's there
+            let exe = exe("rust-llvm-dwp", compiler.host);
+            builder.copy(&src_dir.join(&exe), &dst_dir.join(&exe));
+
             // Man pages
             t!(fs::create_dir_all(image.join("share/man/man1")));
             let man_src = builder.src.join("src/doc/man");