Remap path in MCOptions

Author: cbeuw

compiler/rustc_codegen_llvm/src/back/write.rs

@@ -205,8 +205,11 @@ pub fn target_machine_factory(
     let use_init_array =
         !sess.opts.debugging_opts.use_ctors_section.unwrap_or(sess.target.use_ctors_section);
 
+    let path_mapping = sess.source_map().path_mapping().clone();
+
     Arc::new(move |config: TargetMachineFactoryConfig| {
-        let split_dwarf_file = config.split_dwarf_file.unwrap_or_default();
+        let split_dwarf_file =
+            path_mapping.map_prefix(config.split_dwarf_file.unwrap_or_default()).0;
         let split_dwarf_file = CString::new(split_dwarf_file.to_str().unwrap()).unwrap();
 
         let tm = unsafe {