diff --git a/llvm/lib/DebugInfo/CodeView/DebugInlineeLinesSubsection.cpp b/llvm/lib/DebugInfo/CodeView/DebugInlineeLinesSubsection.cpp
new file mode 100644
index 0000000..a565a6a
--- /dev/null
+++ b/llvm/lib/DebugInfo/CodeView/DebugInlineeLinesSubsection.cpp
@@ -0,0 +1,123 @@
+//===- DebugInlineeLinesSubsection.cpp ------------------------*- 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/CodeView/DebugInlineeLinesSubsection.h"
+
+#include "llvm/DebugInfo/CodeView/CodeViewError.h"
+#include "llvm/DebugInfo/CodeView/DebugChecksumsSubsection.h"
+#include "llvm/DebugInfo/CodeView/DebugSubsectionRecord.h"
+#include "llvm/DebugInfo/CodeView/StringTable.h"
+
+using namespace llvm;
+using namespace llvm::codeview;
+
+Error VarStreamArrayExtractor<InlineeSourceLine>::extract(
+    BinaryStreamRef Stream, uint32_t &Len, InlineeSourceLine &Item,
+    bool HasExtraFiles) {
+  BinaryStreamReader Reader(Stream);
+
+  if (auto EC = Reader.readObject(Item.Header))
+    return EC;
+
+  if (HasExtraFiles) {
+    uint32_t ExtraFileCount;
+    if (auto EC = Reader.readInteger(ExtraFileCount))
+      return EC;
+    if (auto EC = Reader.readArray(Item.ExtraFiles, ExtraFileCount))
+      return EC;
+  }
+
+  Len = Reader.getOffset();
+  return Error::success();
+}
+
+DebugInlineeLinesSubsectionRef::DebugInlineeLinesSubsectionRef()
+    : DebugSubsectionRef(DebugSubsectionKind::InlineeLines) {}
+
+Error DebugInlineeLinesSubsectionRef::initialize(BinaryStreamReader Reader) {
+  if (auto EC = Reader.readEnum(Signature))
+    return EC;
+
+  if (auto EC =
+          Reader.readArray(Lines, Reader.bytesRemaining(), hasExtraFiles()))
+    return EC;
+
+  assert(Reader.bytesRemaining() == 0);
+  return Error::success();
+}
+
+bool DebugInlineeLinesSubsectionRef::hasExtraFiles() const {
+  return Signature == InlineeLinesSignature::ExtraFiles;
+}
+
+DebugInlineeLinesSubsection::DebugInlineeLinesSubsection(
+    DebugChecksumsSubsection &Checksums, bool HasExtraFiles)
+    : DebugSubsection(DebugSubsectionKind::InlineeLines), Checksums(Checksums),
+      HasExtraFiles(HasExtraFiles) {}
+
+uint32_t DebugInlineeLinesSubsection::calculateSerializedLength() {
+  // 4 bytes for the signature
+  uint32_t Size = sizeof(InlineeLinesSignature);
+
+  // one header for each entry.
+  Size += Entries.size() * sizeof(InlineeSourceLineHeader);
+  if (HasExtraFiles) {
+    // If extra files are enabled, one count for each entry.
+    Size += Entries.size() * sizeof(uint32_t);
+
+    // And one file id for each file.
+    Size += ExtraFileCount * sizeof(uint32_t);
+  }
+  assert(Size % 4 == 0);
+  return Size;
+}
+
+Error DebugInlineeLinesSubsection::commit(BinaryStreamWriter &Writer) {
+  InlineeLinesSignature Sig = InlineeLinesSignature::Normal;
+  if (HasExtraFiles)
+    Sig = InlineeLinesSignature::ExtraFiles;
+
+  if (auto EC = Writer.writeEnum(Sig))
+    return EC;
+
+  for (const auto &E : Entries) {
+    if (auto EC = Writer.writeObject(E.Header))
+      return EC;
+
+    if (!HasExtraFiles)
+      continue;
+
+    if (auto EC = Writer.writeInteger<uint32_t>(E.ExtraFiles.size()))
+      return EC;
+    if (auto EC = Writer.writeArray(makeArrayRef(E.ExtraFiles)))
+      return EC;
+  }
+
+  return Error::success();
+}
+
+void DebugInlineeLinesSubsection::addExtraFile(StringRef FileName) {
+  uint32_t Offset = Checksums.mapChecksumOffset(FileName);
+
+  auto &Entry = Entries.back();
+  Entry.ExtraFiles.push_back(ulittle32_t(Offset));
+  ++ExtraFileCount;
+}
+
+void DebugInlineeLinesSubsection::addInlineSite(TypeIndex FuncId,
+                                                StringRef FileName,
+                                                uint32_t SourceLine) {
+  uint32_t Offset = Checksums.mapChecksumOffset(FileName);
+
+  Entries.emplace_back();
+  auto &Entry = Entries.back();
+  Entry.Header.FileID = Offset;
+  Entry.Header.SourceLineNum = SourceLine;
+  Entry.Header.Inlinee = FuncId;
+}