1 files changed, 4 insertions, 2 deletions

diff --git a/lib/CompilerDriver/CompilationGraph.cpp b/lib/CompilerDriver/CompilationGraph.cpp
index 56e5b9ce0761..524607bee779 100644
--- a/lib/CompilerDriver/CompilationGraph.cpp
+++ b/lib/CompilerDriver/CompilationGraph.cpp
@@ -33,9 +33,11 @@ using namespace llvmc;
 namespace llvmc {
 
   const std::string& LanguageMap::GetLanguage(const sys::Path& File) const {
-    LanguageMap::const_iterator Lang = this->find(File.getSuffix());
+    StringRef suf = File.getSuffix();
+    LanguageMap::const_iterator Lang = this->find(suf);
     if (Lang == this->end())
-      throw std::runtime_error(("Unknown suffix: " + File.getSuffix()).str());
+      throw std::runtime_error("File '" + File.str() +
+                                "' has unknown suffix '" + suf.str() + '\'');
     return Lang->second;
   }
 }