Index: lld/ELF/Driver.cpp
===================================================================
--- lld/ELF/Driver.cpp
+++ lld/ELF/Driver.cpp
@@ -1264,10 +1264,18 @@
   for (auto *Arg : Args.filtered(OPT_wrap))
     Symtab->addSymbolWrap<ELFT>(Arg->getValue());
 
+  // Do link-time optimization if given files are LLVM bitcode
+  // files. This compiles bitcode files into real object files.
   Symtab->addCombinedLTOObject<ELFT>();
   if (errorCount())
     return;
 
+  // If -thinlto-index-only is given, we should create only "index
+  // files" and not object files. Index file creation is already done
+  // in addCombinedLTOObject, so we are done if that's the case.
+  if (Config->ThinLTOIndexOnly)
+    return;
+
   // Apply symbol renames for -wrap.
   Symtab->applySymbolWrap();
 
Index: lld/ELF/LTO.cpp
===================================================================
--- lld/ELF/LTO.cpp
+++ lld/ELF/LTO.cpp
@@ -301,7 +301,7 @@
   // files. After that, we exit from linker and ThinLTO backend runs in a
   // distributed environment.
   if (Config->ThinLTOIndexOnly)
-    exit(0);
+    return {};
 
   for (std::unique_ptr<MemoryBuffer> &File : Files)
     if (File)