Don't crash if there is no Inst class in the tablegen file!


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@7402 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/utils/TableGen/TableGen.cpp b/utils/TableGen/TableGen.cpp
index 81529f0..17f2b2e 100644
--- a/utils/TableGen/TableGen.cpp
+++ b/utils/TableGen/TableGen.cpp
@@ -394,10 +394,12 @@
     RemoveFileOnSignal(OutputFilename);
   }
 
+  int ErrorCode = 0;
+
   switch (Action) {
   case Parse: ParseMachineCode(); break;
   case GenEmitter:
-    CodeEmitterGen(Records).createEmitter(*Out);
+    ErrorCode = CodeEmitterGen(Records).createEmitter(*Out);
     break;
   case PrintRecords:
     *Out << Records;           // No argument, dump all contents
@@ -421,5 +423,5 @@
   }
 
   if (Out != &std::cout) delete Out;
-  return 0;
+  return ErrorCode;
 }