Refactor the PDB writing to use a builder approach

llvm-svn: 275110
diff --git a/llvm/lib/DebugInfo/PDB/Raw/InfoStreamBuilder.cpp b/llvm/lib/DebugInfo/PDB/Raw/InfoStreamBuilder.cpp
new file mode 100644
index 0000000..21042e9
--- /dev/null
+++ b/llvm/lib/DebugInfo/PDB/Raw/InfoStreamBuilder.cpp
@@ -0,0 +1,54 @@
+//===- InfoStreamBuilder.cpp - PDB Info Stream Creation ---------*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/DebugInfo/PDB/Raw/InfoStreamBuilder.h"
+
+#include "llvm/DebugInfo/CodeView/StreamWriter.h"
+#include "llvm/DebugInfo/PDB/Raw/InfoStream.h"
+#include "llvm/DebugInfo/PDB/Raw/MappedBlockStream.h"
+#include "llvm/DebugInfo/PDB/Raw/RawError.h"
+
+using namespace llvm;
+using namespace llvm::codeview;
+using namespace llvm::pdb;
+
+InfoStreamBuilder::InfoStreamBuilder(IPDBFile &File) : File(File) {}
+
+void InfoStreamBuilder::setVersion(PdbRaw_ImplVer V) { Ver = V; }
+
+void InfoStreamBuilder::setSignature(uint32_t S) { Sig = S; }
+
+void InfoStreamBuilder::setAge(uint32_t A) { Age = A; }
+
+void InfoStreamBuilder::setGuid(PDB_UniqueId G) { Guid = G; }
+
+Expected<std::unique_ptr<InfoStream>> InfoStreamBuilder::build() {
+  if (!Ver.hasValue())
+    return make_error<RawError>(raw_error_code::unspecified,
+                                "Missing PDB Stream Version");
+  if (!Sig.hasValue())
+    return make_error<RawError>(raw_error_code::unspecified,
+                                "Missing PDB Stream Signature");
+  if (!Age.hasValue())
+    return make_error<RawError>(raw_error_code::unspecified,
+                                "Missing PDB Stream Age");
+  if (!Guid.hasValue())
+    return make_error<RawError>(raw_error_code::unspecified,
+                                "Missing PDB Stream Guid");
+
+  auto InfoS = MappedBlockStream::createIndexedStream(StreamPDB, File);
+  if (!InfoS)
+    return InfoS.takeError();
+  auto Info = llvm::make_unique<InfoStream>(std::move(*InfoS));
+  Info->Version = *Ver;
+  Info->Signature = *Sig;
+  Info->Age = *Age;
+  Info->Guid = *Guid;
+  return std::move(Info);
+}