Cleanup assembly source.

src/librustc/driver/driver.rs

@@ -343,16 +343,21 @@ pub fn phase_5_run_llvm_passes(sess: Session,
         (sess.opts.output_type == link::output_type_object ||
          sess.opts.output_type == link::output_type_exe) {
         let output_type = link::output_type_assembly;
-        let obj_filename = outputs.obj_filename.with_filetype("s");
+        let asm_filename = outputs.obj_filename.with_filetype("s");
 
         time(sess.time_passes(), ~"LLVM passes", ||
             link::write::run_passes(sess,
                                     trans.context,
                                     trans.module,
                                     output_type,
-                                    &obj_filename));
+                                    &asm_filename));
 
-        link::write::run_assembler(sess, &obj_filename, &outputs.obj_filename);
+        link::write::run_assembler(sess, &asm_filename, &outputs.obj_filename);
+
+        // Remove assembly source unless --save-temps was specified
+        if !sess.opts.save_temps {
+            os::remove_file(&asm_filename);
+        }
     } else {
         time(sess.time_passes(), ~"LLVM passes", ||
             link::write::run_passes(sess,