MC: Use reportFatalUsageError for COFF with non-windows

Author: arsenm

llvm/lib/MC/MCContext.cpp

@@ -87,9 +87,10 @@ MCContext::MCContext(const Triple &TheTriple, const MCAsmInfo *mai,
     Env = IsMachO;
     break;
   case Triple::COFF:
-    if (!TheTriple.isOSWindows() && !TheTriple.isUEFI())
-      report_fatal_error(
-          "Cannot initialize MC for non-Windows COFF object files.");
+    if (!TheTriple.isOSWindows() && !TheTriple.isUEFI()) {
+      reportFatalUsageError(
+          "cannot initialize MC for non-Windows COFF object files");
+    }
 
     Env = IsCOFF;
     break;

llvm/test/CodeGen/AArch64/nonwindows-coff-mc-error.ll

@@ -0,0 +1,5 @@
+; RUN: not llc -mtriple=aarch64-unknown-linux-coff -filetype=null %s 2>&1 | FileCheck %s
+; CHECK: LLVM ERROR: cannot initialize MC for non-Windows COFF object files
+define void @foo() {
+  ret void
+}