If we're unable to create the TargetMachine, then just quit producing the

backend output; there's no need to report a fatal error.  This reverts r178042.
Part of rdar://13295753 and rdar://13401547


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@178102 91177308-0d34-0410-b5e6-96231b3b80d8

include/clang/Basic/DiagnosticFrontendKinds.td

@@ -42,6 +42,8 @@ def err_fe_unable_to_load_pch : Error<
     "unable to load PCH file">;
 def err_fe_unable_to_load_plugin : Error<
     "unable to load plugin '%0': '%1'">;
+def err_fe_unable_to_create_target : Error<
+    "unable to create target: '%0'">;
 def err_fe_unable_to_interface_with_target : Error<
     "unable to interface with target machine">;
 def err_fe_unable_to_open_output : Error<

lib/CodeGen/BackendUtil.cpp

@@ -329,7 +329,7 @@ TargetMachine *EmitAssemblyHelper::CreateTargetMachine(bool MustCreateTM) {
   const llvm::Target *TheTarget = TargetRegistry::lookupTarget(Triple, Error);
   if (!TheTarget) {
     if (MustCreateTM)
-      llvm::report_fatal_error ("Unable to create target: " + Error);
+      Diags.Report(diag::err_fe_unable_to_create_target) << Error;
     return 0;
   }
 
@@ -527,6 +527,7 @@ void EmitAssemblyHelper::EmitAssembly(BackendAction Action, raw_ostream *OS) {
                       Action != Backend_EmitBC &&
                       Action != Backend_EmitLL);
   TargetMachine *TM = CreateTargetMachine(UsesCodeGen);
+  if (UsesCodeGen && !TM) return;
   CreatePasses(TM);
 
   switch (Action) {