Merge commit '3a31c6d827' into sync_cg_clif-2021-07-07

compiler/rustc_codegen_cranelift/build_system/utils.rs

@@ -0,0 +1,35 @@
+use std::fs;
+use std::path::Path;
+use std::process::{self, Command};
+
+#[track_caller]
+pub(crate) fn try_hard_link(src: impl AsRef<Path>, dst: impl AsRef<Path>) {
+    let src = src.as_ref();
+    let dst = dst.as_ref();
+    if let Err(_) = fs::hard_link(src, dst) {
+        fs::copy(src, dst).unwrap(); // Fallback to copying if hardlinking failed
+    }
+}
+
+#[track_caller]
+pub(crate) fn spawn_and_wait(mut cmd: Command) {
+    if !cmd.spawn().unwrap().wait().unwrap().success() {
+        process::exit(1);
+    }
+}
+
+pub(crate) fn copy_dir_recursively(from: &Path, to: &Path) {
+    for entry in fs::read_dir(from).unwrap() {
+        let entry = entry.unwrap();
+        let filename = entry.file_name();
+        if filename == "." || filename == ".." {
+            continue;
+        }
+        if entry.metadata().unwrap().is_dir() {
+            fs::create_dir(to.join(&filename)).unwrap();
+            copy_dir_recursively(&from.join(&filename), &to.join(&filename));
+        } else {
+            fs::copy(from.join(&filename), to.join(&filename)).unwrap();
+        }
+    }
+}