Index: cfe/trunk/lib/CodeGen/BackendUtil.cpp
===================================================================
--- cfe/trunk/lib/CodeGen/BackendUtil.cpp
+++ cfe/trunk/lib/CodeGen/BackendUtil.cpp
@@ -231,9 +231,13 @@
     return true;
   case Triple::ELF:
     return CGOpts.DataSections && !CGOpts.DisableIntegratedAS;
-  default:
-    return false;
+  case Triple::XCOFF:
+    llvm::report_fatal_error("ASan not implemented for XCOFF.");
+  case Triple::Wasm:
+  case Triple::UnknownObjectFormat:
+    break;
   }
+  return false;
 }
 
 static void addAddressSanitizerPasses(const PassManagerBuilder &Builder,
Index: llvm/trunk/lib/Transforms/Instrumentation/AddressSanitizer.cpp
===================================================================
--- llvm/trunk/lib/Transforms/Instrumentation/AddressSanitizer.cpp
+++ llvm/trunk/lib/Transforms/Instrumentation/AddressSanitizer.cpp
@@ -1919,7 +1919,12 @@
   case Triple::COFF:  return ".ASAN$GL";
   case Triple::ELF:   return "asan_globals";
   case Triple::MachO: return "__DATA,__asan_globals,regular";
-  default: break;
+  case Triple::Wasm:
+  case Triple::XCOFF:
+    report_fatal_error(
+        "ModuleAddressSanitizer not implemented for object file format.");
+  case Triple::UnknownObjectFormat:
+    break;
   }
   llvm_unreachable("unsupported object format");
 }