am a22ea035: Restore the logging of compilation progress on target device.

* commit 'a22ea0351a9ea781b14f05a7c0d7fde27e5fd9bb':
  Restore the logging of compilation progress on target device.
diff --git a/src/compiler_llvm/compilation_unit.cc b/src/compiler_llvm/compilation_unit.cc
index 4be6a90..70bfd1e 100644
--- a/src/compiler_llvm/compilation_unit.cc
+++ b/src/compiler_llvm/compilation_unit.cc
@@ -171,7 +171,9 @@
 
   if (thread_count == 1) {
     llvm::raw_string_ostream str_os(elf_image_);
-    return MaterializeToFile(str_os, insn_set_);
+    bool success = MaterializeToFile(str_os, insn_set_);
+    LOG(INFO) << "Compilation Unit: " << elf_idx_ << (success ? " (done)" : " (failed)");
+    return success;
   }
 
   // Prepare the pipe between parent process and child process