ForceFunctionAttrs: Use reportFatalUsageError

Also add a missing test for the failure.

Author: arsenm

llvm/lib/Transforms/IPO/ForceFunctionAttrs.cpp

@@ -92,7 +92,7 @@ PreservedAnalyses ForceFunctionAttrsPass::run(Module &M,
   if (!CSVFilePath.empty()) {
     auto BufferOrError = MemoryBuffer::getFileOrSTDIN(CSVFilePath);
     if (!BufferOrError)
-      report_fatal_error("Cannot open CSV file.");
+      reportFatalUsageError("cannot open CSV file");
     StringRef Buffer = BufferOrError.get()->getBuffer();
     auto MemoryBuffer = MemoryBuffer::getMemBuffer(Buffer);
     line_iterator It(*MemoryBuffer);

llvm/test/Transforms/ForcedFunctionAttrs/open-file-error.ll

@@ -0,0 +1,6 @@
+; RUN: not opt -disable-output -passes='forceattrs' -forceattrs-csv-path="%S/CannotOpenFile.csv"  %s 2>&1 | FileCheck %s
+
+; CHECK: LLVM ERROR: cannot open CSV file
+define void @first_function() {
+  ret void
+}