From 92fa2508c448b45752ab68b640dd92f339302161 Mon Sep 17 00:00:00 2001
From: Tex Riddell <texr@microsoft.com>
Date: Tue, 16 Mar 2021 08:22:34 -0700
Subject: [PATCH] Filecheck: Allow empty stderr input; replace last couple
 errs() uses (#3588)

---
 tools/clang/unittests/HLSLTestLib/FileCheckForTest.cpp | 4 ++--
 tools/clang/unittests/HLSLTestLib/FileCheckerTest.cpp  | 6 ++++--
 2 files changed, 6 insertions(+), 4 deletions(-)

diff --git a/tools/clang/unittests/HLSLTestLib/FileCheckForTest.cpp b/tools/clang/unittests/HLSLTestLib/FileCheckForTest.cpp
index ea3b58d44..308d9e23d 100644
--- a/tools/clang/unittests/HLSLTestLib/FileCheckForTest.cpp
+++ b/tools/clang/unittests/HLSLTestLib/FileCheckForTest.cpp
@@ -1333,14 +1333,14 @@ int run_main() {
     MemoryBuffer::getMemBuffer(MemoryBufferRef(StringRef(InputForStdin), "-")) :
     MemoryBuffer::getFile(InputFilename);
   if (std::error_code EC = FileOrErr.getError()) {
-    errs() << "Could not open input file '" << InputFilename
+    test_errs << "Could not open input file '" << InputFilename
       << "': " << EC.message() << '\n';
     return 2;
   }
   std::unique_ptr<MemoryBuffer> &File = FileOrErr.get();
 
   if (File->getBufferSize() == 0 && !AllowEmptyInput) {
-    errs() << "FileCheck error: '" << InputFilename << "' is empty.\n";
+    test_errs << "FileCheck error: '" << InputFilename << "' is empty.\n";
     return 2;
   }
 
diff --git a/tools/clang/unittests/HLSLTestLib/FileCheckerTest.cpp b/tools/clang/unittests/HLSLTestLib/FileCheckerTest.cpp
index 87209490f..fbfb62f87 100644
--- a/tools/clang/unittests/HLSLTestLib/FileCheckerTest.cpp
+++ b/tools/clang/unittests/HLSLTestLib/FileCheckerTest.cpp
@@ -139,8 +139,10 @@ FileRunCommandResult FileRunCommandPart::RunFileChecker(const FileRunCommandResu
   auto args = strtok(Arguments);
   for (const std::string& arg : args) {
     if (arg == "%s") hasInputFilename = true;
-    else if (arg == "-input=stderr") t.InputForStdin = Prior->StdErr;
-    else if (strstartswith(arg, checkPrefixStr))
+    else if (arg == "-input=stderr") {
+      t.InputForStdin = Prior->StdErr;
+      t.AllowEmptyInput = true;
+    } else if (strstartswith(arg, checkPrefixStr))
       t.CheckPrefixes.emplace_back(arg.substr(sizeof(checkPrefixStr) - 1));
     else if (strstartswith(arg, checkPrefixesStr)) {
       auto prefixes = strtok(arg.substr(sizeof(checkPrefixesStr) - 1), ", ");