[Remarks] Simplify the creation of remark serializers

Introduce two new functions to create a serializer, and add support for
more combinations to the YAMLStrTabSerializer.

llvm-svn: 366919
diff --git a/llvm/lib/Remarks/RemarkSerializer.cpp b/llvm/lib/Remarks/RemarkSerializer.cpp
new file mode 100644
index 0000000..b1cfd09
--- /dev/null
+++ b/llvm/lib/Remarks/RemarkSerializer.cpp
@@ -0,0 +1,48 @@
+//===- RemarkSerializer.cpp -----------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+//
+// This file provides tools for serializing remarks.
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/Remarks/RemarkSerializer.h"
+#include "llvm/Remarks/YAMLRemarkSerializer.h"
+
+using namespace llvm;
+using namespace llvm::remarks;
+
+Expected<std::unique_ptr<Serializer>>
+remarks::createRemarkSerializer(Format RemarksFormat, raw_ostream &OS) {
+  switch (RemarksFormat) {
+  case Format::Unknown:
+    return createStringError(std::errc::invalid_argument,
+                             "Unknown remark serializer format.");
+  case Format::YAML:
+    return llvm::make_unique<YAMLSerializer>(OS);
+  case Format::YAMLStrTab:
+    return llvm::make_unique<YAMLStrTabSerializer>(OS);
+  }
+  llvm_unreachable("Unknown remarks::Format enum");
+}
+
+Expected<std::unique_ptr<Serializer>>
+remarks::createRemarkSerializer(Format RemarksFormat, raw_ostream &OS,
+                                remarks::StringTable StrTab) {
+  switch (RemarksFormat) {
+  case Format::Unknown:
+    return createStringError(std::errc::invalid_argument,
+                             "Unknown remark serializer format.");
+  case Format::YAML:
+    return createStringError(std::errc::invalid_argument,
+                             "Unable to use a string table with the yaml "
+                             "format. Use 'yaml-strtab' instead.");
+  case Format::YAMLStrTab:
+    return llvm::make_unique<YAMLStrTabSerializer>(OS, std::move(StrTab));
+  }
+  llvm_unreachable("Unknown remarks::Format enum");
+}