Move SafeStack to CodeGen.

It depends on the target machinery, that's not available for
instrumentation passes.

llvm-svn: 258942
diff --git a/llvm/lib/CodeGen/CodeGen.cpp b/llvm/lib/CodeGen/CodeGen.cpp
index dc13b5b..3c2dc85 100644
--- a/llvm/lib/CodeGen/CodeGen.cpp
+++ b/llvm/lib/CodeGen/CodeGen.cpp
@@ -68,6 +68,7 @@
   initializeStackColoringPass(Registry);
   initializeStackMapLivenessPass(Registry);
   initializeLiveDebugValuesPass(Registry);
+  initializeSafeStackPass(Registry);
   initializeStackProtectorPass(Registry);
   initializeStackSlotColoringPass(Registry);
   initializeTailDuplicatePassPass(Registry);