[CodeView] Support CodeView subsections in any order.

Previously we would expect certain subsections to appear
in a certain order because some subsections would reference
other subsections, but in practice we need to support
arbitrary orderings since some object file and PDB file
producers generate them this way.  This also paves the
way for supporting Yaml <-> Object File conversion of
CodeView, since Object Files typically have quite a
large number of subsections in their debug info.

Differential Revision: https://reviews.llvm.org/D33807

llvm-svn: 304588

21 files changed, 549 insertions, 335 deletions

diff --git a/llvm/include/llvm/DebugInfo/CodeView/DebugChecksumsSubsection.h b/llvm/include/llvm/DebugInfo/CodeView/DebugChecksumsSubsection.h
index e7036033d2d..c958a95ee6d 100644
--- a/llvm/include/llvm/DebugInfo/CodeView/DebugChecksumsSubsection.h
+++ b/llvm/include/llvm/DebugInfo/CodeView/DebugChecksumsSubsection.h
@@ -60,8 +60,8 @@ public:
   Error initialize(BinaryStreamReader Reader);
   Error initialize(BinaryStreamRef Stream);
 
-  Iterator begin() { return Checksums.begin(); }
-  Iterator end() { return Checksums.end(); }
+  Iterator begin() const { return Checksums.begin(); }
+  Iterator end() const { return Checksums.end(); }
 
   const FileChecksumArray &getArray() const { return Checksums; }
 
diff --git a/llvm/include/llvm/DebugInfo/CodeView/DebugInlineeLinesSubsection.h b/llvm/include/llvm/DebugInfo/CodeView/DebugInlineeLinesSubsection.h
index e2cfc3c9923..60440700c26 100644
--- a/llvm/include/llvm/DebugInfo/CodeView/DebugInlineeLinesSubsection.h
+++ b/llvm/include/llvm/DebugInfo/CodeView/DebugInlineeLinesSubsection.h
@@ -74,8 +74,13 @@ private:
 
 class DebugInlineeLinesSubsection final : public DebugSubsection {
 public:
+  struct Entry {
+    std::vector<support::ulittle32_t> ExtraFiles;
+    InlineeSourceLineHeader Header;
+  };
+
   DebugInlineeLinesSubsection(DebugChecksumsSubsection &Checksums,
-                              bool HasExtraFiles);
+                              bool HasExtraFiles = false);
 
   static bool classof(const DebugSubsection *S) {
     return S->kind() == DebugSubsectionKind::InlineeLines;
@@ -87,16 +92,18 @@ public:
   void addInlineSite(TypeIndex FuncId, StringRef FileName, uint32_t SourceLine);
   void addExtraFile(StringRef FileName);
 
+  bool hasExtraFiles() const { return HasExtraFiles; }
+  void setHasExtraFiles(bool Has) { HasExtraFiles = Has; }
+
+  std::vector<Entry>::const_iterator begin() const { return Entries.begin(); }
+  std::vector<Entry>::const_iterator end() const { return Entries.end(); }
+
 private:
   DebugChecksumsSubsection &Checksums;
 
   bool HasExtraFiles = false;
   uint32_t ExtraFileCount = 0;
 
-  struct Entry {
-    std::vector<support::ulittle32_t> ExtraFiles;
-    InlineeSourceLineHeader Header;
-  };
   std::vector<Entry> Entries;
 };
 }
diff --git a/llvm/include/llvm/DebugInfo/CodeView/DebugSubsectionRecord.h b/llvm/include/llvm/DebugInfo/CodeView/DebugSubsectionRecord.h
index 3058157590e..847259c5cea 100644
--- a/llvm/include/llvm/DebugInfo/CodeView/DebugSubsectionRecord.h
+++ b/llvm/include/llvm/DebugInfo/CodeView/DebugSubsectionRecord.h
@@ -49,15 +49,14 @@ private:
 
 class DebugSubsectionRecordBuilder {
 public:
-  DebugSubsectionRecordBuilder(DebugSubsectionKind Kind, DebugSubsection &Frag,
+  DebugSubsectionRecordBuilder(std::unique_ptr<DebugSubsection> Subsection,
                                CodeViewContainer Container);
   uint32_t calculateSerializedLength();
   Error commit(BinaryStreamWriter &Writer);
 
 private:
+  std::unique_ptr<DebugSubsection> Subsection;
   CodeViewContainer Container;
-  DebugSubsectionKind Kind;
-  DebugSubsection &Frag;
 };
 
 } // namespace codeview
diff --git a/llvm/include/llvm/DebugInfo/PDB/Native/DbiModuleDescriptorBuilder.h b/llvm/include/llvm/DebugInfo/PDB/Native/DbiModuleDescriptorBuilder.h
index e5858d0f45e..2ff166b24e6 100644
--- a/llvm/include/llvm/DebugInfo/PDB/Native/DbiModuleDescriptorBuilder.h
+++ b/llvm/include/llvm/DebugInfo/PDB/Native/DbiModuleDescriptorBuilder.h
@@ -49,11 +49,8 @@ public:
   void setObjFileName(StringRef Name);
   void addSymbol(codeview::CVSymbol Symbol);
 
-  void addC13Fragment(std::unique_ptr<codeview::DebugLinesSubsection> Lines);
-  void addC13Fragment(
-      std::unique_ptr<codeview::DebugInlineeLinesSubsection> Inlinees);
-  void setC13FileChecksums(
-      std::unique_ptr<codeview::DebugChecksumsSubsection> Checksums);
+  void
+  addDebugSubsection(std::unique_ptr<codeview::DebugSubsection> Subsection);
 
   uint16_t getStreamIndex() const;
   StringRef getModuleName() const { return ModuleName; }
@@ -83,10 +80,6 @@ private:
   std::vector<std::string> SourceFiles;
   std::vector<codeview::CVSymbol> Symbols;
 
-  std::unique_ptr<codeview::DebugChecksumsSubsection> ChecksumInfo;
-  std::vector<std::unique_ptr<codeview::DebugLinesSubsection>> LineInfo;
-  std::vector<std::unique_ptr<codeview::DebugInlineeLinesSubsection>> Inlinees;
-
   std::vector<std::unique_ptr<codeview::DebugSubsectionRecordBuilder>>
       C13Builders;
 
diff --git a/llvm/include/llvm/DebugInfo/PDB/Native/ModuleDebugStream.h b/llvm/include/llvm/DebugInfo/PDB/Native/ModuleDebugStream.h
index 822ce3ce13d..a8121978d88 100644
--- a/llvm/include/llvm/DebugInfo/PDB/Native/ModuleDebugStream.h
+++ b/llvm/include/llvm/DebugInfo/PDB/Native/ModuleDebugStream.h
@@ -12,6 +12,7 @@
 
 #include "llvm/ADT/iterator_range.h"
 #include "llvm/DebugInfo/CodeView/CVRecord.h"
+#include "llvm/DebugInfo/CodeView/DebugChecksumsSubsection.h"
 #include "llvm/DebugInfo/CodeView/DebugSubsectionRecord.h"
 #include "llvm/DebugInfo/CodeView/SymbolRecord.h"
 #include "llvm/DebugInfo/MSF/MappedBlockStream.h"
@@ -25,7 +26,7 @@ class PDBFile;
 class DbiModuleDescriptor;
 
 class ModuleDebugStreamRef {
-  typedef codeview::DebugSubsectionArray::Iterator LinesAndChecksumsIterator;
+  typedef codeview::DebugSubsectionArray::Iterator DebugSubsectionIterator;
 
 public:
   ModuleDebugStreamRef(const DbiModuleDescriptor &Module,
@@ -39,12 +40,15 @@ public:
   iterator_range<codeview::CVSymbolArray::Iterator>
   symbols(bool *HadError) const;
 
-  llvm::iterator_range<LinesAndChecksumsIterator> linesAndChecksums() const;
+  llvm::iterator_range<DebugSubsectionIterator> subsections() const;
 
-  bool hasLineInfo() const;
+  bool hasDebugSubsections() const;
 
   Error commit();
 
+  Expected<codeview::DebugChecksumsSubsectionRef>
+  findChecksumsSubsection() const;
+
 private:
   const DbiModuleDescriptor &Mod;
 
@@ -57,7 +61,7 @@ private:
   BinaryStreamRef C13LinesSubstream;
   BinaryStreamRef GlobalRefsSubstream;
 
-  codeview::DebugSubsectionArray LinesAndChecksums;
+  codeview::DebugSubsectionArray Subsections;
 };
 }
 }
diff --git a/llvm/include/llvm/DebugInfo/PDB/Native/PDBStringTable.h b/llvm/include/llvm/DebugInfo/PDB/Native/PDBStringTable.h
index 6aeb0a5479c..28a14d7356d 100644
--- a/llvm/include/llvm/DebugInfo/PDB/Native/PDBStringTable.h
+++ b/llvm/include/llvm/DebugInfo/PDB/Native/PDBStringTable.h
@@ -45,6 +45,8 @@ public:
 
   FixedStreamArray<support::ulittle32_t> name_ids() const;
 
+  codeview::DebugStringTableSubsectionRef getStringTable() const;
+
 private:
   Error readHeader(BinaryStreamReader &Reader);
   Error readStrings(BinaryStreamReader &Reader);
diff --git a/llvm/include/llvm/ObjectYAML/CodeViewYAMLDebugSections.h b/llvm/include/llvm/ObjectYAML/CodeViewYAMLDebugSections.h
index 6ddae2e2b41..a6d4d404415 100644
--- a/llvm/include/llvm/ObjectYAML/CodeViewYAMLDebugSections.h
+++ b/llvm/include/llvm/ObjectYAML/CodeViewYAMLDebugSections.h
@@ -17,12 +17,20 @@
 
 #include "llvm/DebugInfo/CodeView/CodeView.h"
 #include "llvm/DebugInfo/CodeView/DebugSubsection.h"
+#include "llvm/DebugInfo/CodeView/DebugSubsectionRecord.h"
 #include "llvm/ObjectYAML/YAML.h"
 
 namespace llvm {
+
+namespace codeview {
+class DebugStringTableSubsection;
+class DebugStringTableSubsectionRef;
+class DebugChecksumsSubsectionRef;
+}
 namespace CodeViewYAML {
+
 namespace detail {
-struct C13FragmentBase;
+struct YAMLSubsectionBase;
 }
 
 struct SourceLineEntry {
@@ -74,18 +82,24 @@ struct InlineeInfo {
   std::vector<InlineeSite> Sites;
 };
 
-struct SourceFileInfo {
-  std::vector<SourceFileChecksumEntry> FileChecksums;
-  std::vector<SourceLineInfo> LineFragments;
-  std::vector<InlineeInfo> Inlinees;
-};
+struct YAMLDebugSubsection {
+  static Expected<YAMLDebugSubsection>
+  fromCodeViewSubection(const codeview::DebugStringTableSubsectionRef &Strings,
+                        const codeview::DebugChecksumsSubsectionRef &Checksums,
+                        const codeview::DebugSubsectionRecord &SS);
 
-struct C13DebugSection {
-  std::vector<detail::C13FragmentBase> Fragments;
+  std::shared_ptr<detail::YAMLSubsectionBase> Subsection;
 };
+
+Expected<std::vector<std::unique_ptr<codeview::DebugSubsection>>>
+convertSubsectionList(ArrayRef<YAMLDebugSubsection> Subsections,
+                      codeview::DebugStringTableSubsection &Strings);
+
 } // namespace CodeViewYAML
 } // namespace llvm
 
-LLVM_YAML_DECLARE_MAPPING_TRAITS(CodeViewYAML::SourceFileInfo)
+LLVM_YAML_DECLARE_MAPPING_TRAITS(CodeViewYAML::YAMLDebugSubsection)
+
+LLVM_YAML_IS_SEQUENCE_VECTOR(CodeViewYAML::YAMLDebugSubsection)
 
 #endif
diff --git a/llvm/lib/DebugInfo/CodeView/DebugStringTableSubsection.cpp b/llvm/lib/DebugInfo/CodeView/DebugStringTableSubsection.cpp
index b8741eb0b67..2e72242181b 100644
--- a/llvm/lib/DebugInfo/CodeView/DebugStringTableSubsection.cpp
+++ b/llvm/lib/DebugInfo/CodeView/DebugStringTableSubsection.cpp
@@ -72,7 +72,7 @@ Error DebugStringTableSubsection::commit(BinaryStreamWriter &Writer) const {
 uint32_t DebugStringTableSubsection::size() const { return Strings.size(); }
 
 uint32_t DebugStringTableSubsection::getStringId(StringRef S) const {
-  auto P = Strings.find(S);
-  assert(P != Strings.end());
-  return P->second;
+  auto Iter = Strings.find(S);
+  assert(Iter != Strings.end());
+  return Iter->second;
 }
diff --git a/llvm/lib/DebugInfo/CodeView/DebugSubsectionRecord.cpp b/llvm/lib/DebugInfo/CodeView/DebugSubsectionRecord.cpp
index 5ecfaf2f23a..cfd1c5d3ab0 100644
--- a/llvm/lib/DebugInfo/CodeView/DebugSubsectionRecord.cpp
+++ b/llvm/lib/DebugInfo/CodeView/DebugSubsectionRecord.cpp
@@ -60,13 +60,13 @@ DebugSubsectionKind DebugSubsectionRecord::kind() const { return Kind; }
 BinaryStreamRef DebugSubsectionRecord::getRecordData() const { return Data; }
 
 DebugSubsectionRecordBuilder::DebugSubsectionRecordBuilder(
-    DebugSubsectionKind Kind, DebugSubsection &Frag,
-    CodeViewContainer Container)
-    : Container(Container), Kind(Kind), Frag(Frag) {}
+    std::unique_ptr<DebugSubsection> Subsection, CodeViewContainer Container)
+    : Subsection(std::move(Subsection)), Container(Container) {}
 
 uint32_t DebugSubsectionRecordBuilder::calculateSerializedLength() {
-  uint32_t Size = sizeof(DebugSubsectionHeader) +
-                  alignTo(Frag.calculateSerializedSize(), alignOf(Container));
+  uint32_t Size =
+      sizeof(DebugSubsectionHeader) +
+      alignTo(Subsection->calculateSerializedSize(), alignOf(Container));
   return Size;
 }
 
@@ -75,12 +75,12 @@ Error DebugSubsectionRecordBuilder::commit(BinaryStreamWriter &Writer) {
          "Debug Subsection not properly aligned");
 
   DebugSubsectionHeader Header;
-  Header.Kind = uint32_t(Kind);
+  Header.Kind = uint32_t(Subsection->kind());
   Header.Length = calculateSerializedLength() - sizeof(DebugSubsectionHeader);
 
   if (auto EC = Writer.writeObject(Header))
     return EC;
-  if (auto EC = Frag.commit(Writer))
+  if (auto EC = Subsection->commit(Writer))
     return EC;
   if (auto EC = Writer.padToAlignment(alignOf(Container)))
     return EC;
diff --git a/llvm/lib/DebugInfo/PDB/Native/DbiModuleDescriptorBuilder.cpp b/llvm/lib/DebugInfo/PDB/Native/DbiModuleDescriptorBuilder.cpp
index bf3f83741ae..9aea4acb74a 100644
--- a/llvm/lib/DebugInfo/PDB/Native/DbiModuleDescriptorBuilder.cpp
+++ b/llvm/lib/DebugInfo/PDB/Native/DbiModuleDescriptorBuilder.cpp
@@ -174,42 +174,9 @@ Error DbiModuleDescriptorBuilder::commit(BinaryStreamWriter &ModiWriter,
   return Error::success();
 }
 
-void DbiModuleDescriptorBuilder::addC13Fragment(
-    std::unique_ptr<DebugLinesSubsection> Lines) {
-  DebugLinesSubsection &Frag = *Lines;
-
-  // File Checksums have to come first, so push an empty entry on if this
-  // is the first.
-  if (C13Builders.empty())
-    C13Builders.push_back(nullptr);
-
-  this->LineInfo.push_back(std::move(Lines));
+void DbiModuleDescriptorBuilder::addDebugSubsection(
+    std::unique_ptr<DebugSubsection> Subsection) {
+  assert(Subsection);
   C13Builders.push_back(llvm::make_unique<DebugSubsectionRecordBuilder>(
-      Frag.kind(), Frag, CodeViewContainer::Pdb));
-}
-
-void DbiModuleDescriptorBuilder::addC13Fragment(
-    std::unique_ptr<codeview::DebugInlineeLinesSubsection> Inlinees) {
-  DebugInlineeLinesSubsection &Frag = *Inlinees;
-
-  // File Checksums have to come first, so push an empty entry on if this
-  // is the first.
-  if (C13Builders.empty())
-    C13Builders.push_back(nullptr);
-
-  this->Inlinees.push_back(std::move(Inlinees));
-  C13Builders.push_back(llvm::make_unique<DebugSubsectionRecordBuilder>(
-      Frag.kind(), Frag, CodeViewContainer::Pdb));
-}
-
-void DbiModuleDescriptorBuilder::setC13FileChecksums(
-    std::unique_ptr<DebugChecksumsSubsection> Checksums) {
-  assert(!ChecksumInfo && "Can't have more than one checksum info!");
-
-  if (C13Builders.empty())
-    C13Builders.push_back(nullptr);
-
-  ChecksumInfo = std::move(Checksums);
-  C13Builders[0] = llvm::make_unique<DebugSubsectionRecordBuilder>(
-      ChecksumInfo->kind(), *ChecksumInfo, CodeViewContainer::Pdb);
+      std::move(Subsection), CodeViewContainer::Pdb));
 }
diff --git a/llvm/lib/DebugInfo/PDB/Native/ModuleDebugStream.cpp b/llvm/lib/DebugInfo/PDB/Native/ModuleDebugStream.cpp
index d7a203746a0..c4ff30011a1 100644
--- a/llvm/lib/DebugInfo/PDB/Native/ModuleDebugStream.cpp
+++ b/llvm/lib/DebugInfo/PDB/Native/ModuleDebugStream.cpp
@@ -55,9 +55,9 @@ Error ModuleDebugStreamRef::reload() {
   if (auto EC = Reader.readStreamRef(C13LinesSubstream, C13Size))
     return EC;
 
-  BinaryStreamReader LineReader(C13LinesSubstream);
-  if (auto EC =
-          LineReader.readArray(LinesAndChecksums, LineReader.bytesRemaining()))
+  BinaryStreamReader SubsectionsReader(C13LinesSubstream);
+  if (auto EC = SubsectionsReader.readArray(Subsections,
+                                            SubsectionsReader.bytesRemaining()))
     return EC;
 
   uint32_t GlobalRefsSize;
@@ -77,13 +77,27 @@ ModuleDebugStreamRef::symbols(bool *HadError) const {
   return make_range(SymbolsSubstream.begin(HadError), SymbolsSubstream.end());
 }
 
-llvm::iterator_range<ModuleDebugStreamRef::LinesAndChecksumsIterator>
-ModuleDebugStreamRef::linesAndChecksums() const {
-  return make_range(LinesAndChecksums.begin(), LinesAndChecksums.end());
+llvm::iterator_range<ModuleDebugStreamRef::DebugSubsectionIterator>
+ModuleDebugStreamRef::subsections() const {
+  return make_range(Subsections.begin(), Subsections.end());
 }
 
-bool ModuleDebugStreamRef::hasLineInfo() const {
+bool ModuleDebugStreamRef::hasDebugSubsections() const {
   return C13LinesSubstream.getLength() > 0;
 }
 
 Error ModuleDebugStreamRef::commit() { return Error::success(); }
+
+Expected<codeview::DebugChecksumsSubsectionRef>
+ModuleDebugStreamRef::findChecksumsSubsection() const {
+  for (const auto &SS : subsections()) {
+    if (SS.kind() != DebugSubsectionKind::FileChecksums)
+      continue;
+
+    codeview::DebugChecksumsSubsectionRef Result;
+    if (auto EC = Result.initialize(SS.getRecordData()))
+      return std::move(EC);
+    return Result;
+  }
+  return make_error<RawError>(raw_error_code::no_entry);
+}
diff --git a/llvm/lib/DebugInfo/PDB/Native/PDBStringTable.cpp b/llvm/lib/DebugInfo/PDB/Native/PDBStringTable.cpp
index e84573fe07b..6013c342cf0 100644
--- a/llvm/lib/DebugInfo/PDB/Native/PDBStringTable.cpp
+++ b/llvm/lib/DebugInfo/PDB/Native/PDBStringTable.cpp
@@ -56,6 +56,10 @@ Error PDBStringTable::readStrings(BinaryStreamReader &Reader) {
   return Error::success();
 }
 
+codeview::DebugStringTableSubsectionRef PDBStringTable::getStringTable() const {
+  return Strings;
+}
+
 Error PDBStringTable::readHashTable(BinaryStreamReader &Reader) {
   const support::ulittle32_t *HashCount;
   if (auto EC = Reader.readObject(HashCount))
diff --git a/llvm/lib/ObjectYAML/CodeViewYAMLDebugSections.cpp b/llvm/lib/ObjectYAML/CodeViewYAMLDebugSections.cpp
index f652ff57f30..1d62d1b2621 100644
--- a/llvm/lib/ObjectYAML/CodeViewYAMLDebugSections.cpp
+++ b/llvm/lib/ObjectYAML/CodeViewYAMLDebugSections.cpp
@@ -17,6 +17,11 @@
 #include "llvm/ADT/StringExtras.h"
 #include "llvm/ADT/StringSwitch.h"
 #include "llvm/DebugInfo/CodeView/CodeViewError.h"
+#include "llvm/DebugInfo/CodeView/DebugChecksumsSubsection.h"
+#include "llvm/DebugInfo/CodeView/DebugInlineeLinesSubsection.h"
+#include "llvm/DebugInfo/CodeView/DebugLinesSubsection.h"
+#include "llvm/DebugInfo/CodeView/DebugStringTableSubsection.h"
+#include "llvm/DebugInfo/CodeView/DebugSubsectionVisitor.h"
 #include "llvm/DebugInfo/CodeView/EnumTables.h"
 #include "llvm/DebugInfo/CodeView/SymbolRecord.h"
 
@@ -36,16 +41,80 @@ LLVM_YAML_IS_SEQUENCE_VECTOR(InlineeInfo)
 LLVM_YAML_IS_SEQUENCE_VECTOR(StringRef)
 
 LLVM_YAML_DECLARE_SCALAR_TRAITS(HexFormattedString, false)
+LLVM_YAML_DECLARE_ENUM_TRAITS(DebugSubsectionKind)
 LLVM_YAML_DECLARE_ENUM_TRAITS(FileChecksumKind)
 LLVM_YAML_DECLARE_BITSET_TRAITS(LineFlags)
 
-LLVM_YAML_DECLARE_MAPPING_TRAITS(CodeViewYAML::SourceLineEntry)
-LLVM_YAML_DECLARE_MAPPING_TRAITS(CodeViewYAML::SourceColumnEntry)
-LLVM_YAML_DECLARE_MAPPING_TRAITS(CodeViewYAML::SourceFileChecksumEntry)
-LLVM_YAML_DECLARE_MAPPING_TRAITS(CodeViewYAML::SourceLineInfo)
-LLVM_YAML_DECLARE_MAPPING_TRAITS(CodeViewYAML::SourceLineBlock)
-LLVM_YAML_DECLARE_MAPPING_TRAITS(CodeViewYAML::InlineeInfo)
-LLVM_YAML_DECLARE_MAPPING_TRAITS(CodeViewYAML::InlineeSite)
+LLVM_YAML_DECLARE_MAPPING_TRAITS(SourceLineEntry)
+LLVM_YAML_DECLARE_MAPPING_TRAITS(SourceColumnEntry)
+LLVM_YAML_DECLARE_MAPPING_TRAITS(SourceFileChecksumEntry)
+LLVM_YAML_DECLARE_MAPPING_TRAITS(SourceLineBlock)
+LLVM_YAML_DECLARE_MAPPING_TRAITS(InlineeSite)
+
+namespace llvm {
+namespace CodeViewYAML {
+namespace detail {
+struct YAMLSubsectionBase {
+  explicit YAMLSubsectionBase(DebugSubsectionKind Kind) : Kind(Kind) {}
+  DebugSubsectionKind Kind;
+  virtual ~YAMLSubsectionBase() {}
+
+  virtual void map(IO &IO) = 0;
+  virtual std::unique_ptr<DebugSubsection>
+  toCodeViewSubsection(DebugStringTableSubsection *UseStrings,
+                       DebugChecksumsSubsection *UseChecksums) const = 0;
+};
+}
+}
+}
+
+namespace {
+struct YAMLChecksumsSubsection : public YAMLSubsectionBase {
+  YAMLChecksumsSubsection()
+      : YAMLSubsectionBase(DebugSubsectionKind::FileChecksums) {}
+
+  void map(IO &IO) override;
+  std::unique_ptr<DebugSubsection>
+  toCodeViewSubsection(DebugStringTableSubsection *Strings,
+                       DebugChecksumsSubsection *Checksums) const override;
+  static Expected<std::shared_ptr<YAMLChecksumsSubsection>>
+  fromCodeViewSubsection(const DebugStringTableSubsectionRef &Strings,
+                         const DebugChecksumsSubsectionRef &FC);
+
+  std::vector<SourceFileChecksumEntry> Checksums;
+};
+
+struct YAMLLinesSubsection : public YAMLSubsectionBase {
+  YAMLLinesSubsection() : YAMLSubsectionBase(DebugSubsectionKind::Lines) {}
+
+  void map(IO &IO) override;
+  std::unique_ptr<DebugSubsection>
+  toCodeViewSubsection(DebugStringTableSubsection *Strings,
+                       DebugChecksumsSubsection *Checksums) const override;
+  static Expected<std::shared_ptr<YAMLLinesSubsection>>
+  fromCodeViewSubsection(const DebugStringTableSubsectionRef &Strings,
+                         const DebugChecksumsSubsectionRef &Checksums,
+                         const DebugLinesSubsectionRef &Lines);
+
+  SourceLineInfo Lines;
+};
+
+struct YAMLInlineeLinesSubsection : public YAMLSubsectionBase {
+  YAMLInlineeLinesSubsection()
+      : YAMLSubsectionBase(DebugSubsectionKind::InlineeLines) {}
+
+  void map(IO &IO) override;
+  std::unique_ptr<DebugSubsection>
+  toCodeViewSubsection(DebugStringTableSubsection *Strings,
+                       DebugChecksumsSubsection *Checksums) const override;
+  static Expected<std::shared_ptr<YAMLInlineeLinesSubsection>>
+  fromCodeViewSubsection(const DebugStringTableSubsectionRef &Strings,
+                         const DebugChecksumsSubsectionRef &Checksums,
+                         const DebugInlineeLinesSubsectionRef &Lines);
+
+  InlineeInfo InlineeLines;
+};
+}
 
 void ScalarBitSetTraits<LineFlags>::bitset(IO &io, LineFlags &Flags) {
   io.bitSetCase(Flags, "HasColumnInfo", LF_HaveColumns);
@@ -99,21 +168,6 @@ void MappingTraits<SourceFileChecksumEntry>::mapping(
   IO.mapRequired("Checksum", Obj.ChecksumBytes);
 }
 
-void MappingTraits<SourceLineInfo>::mapping(IO &IO, SourceLineInfo &Obj) {
-  IO.mapRequired("CodeSize", Obj.CodeSize);
-
-  IO.mapRequired("Flags", Obj.Flags);
-  IO.mapRequired("RelocOffset", Obj.RelocOffset);
-  IO.mapRequired("RelocSegment", Obj.RelocSegment);
-  IO.mapRequired("Blocks", Obj.Blocks);
-}
-
-void MappingTraits<SourceFileInfo>::mapping(IO &IO, SourceFileInfo &Obj) {
-  IO.mapOptional("Checksums", Obj.FileChecksums);
-  IO.mapOptional("Lines", Obj.LineFragments);
-  IO.mapOptional("InlineeLines", Obj.Inlinees);
-}
-
 void MappingTraits<InlineeSite>::mapping(IO &IO, InlineeSite &Obj) {
   IO.mapRequired("FileName", Obj.FileName);
   IO.mapRequired("LineNum", Obj.SourceLineNum);
@@ -121,7 +175,310 @@ void MappingTraits<InlineeSite>::mapping(IO &IO, InlineeSite &Obj) {
   IO.mapOptional("ExtraFiles", Obj.ExtraFiles);
 }
 
-void MappingTraits<InlineeInfo>::mapping(IO &IO, InlineeInfo &Obj) {
-  IO.mapRequired("HasExtraFiles", Obj.HasExtraFiles);
-  IO.mapRequired("Sites", Obj.Sites);
+void YAMLChecksumsSubsection::map(IO &IO) {
+  IO.mapTag("!FileChecksums", true);
+  IO.mapRequired("Checksums", Checksums);
+}
+
+void YAMLLinesSubsection::map(IO &IO) {
+  IO.mapTag("!Lines", true);
+  IO.mapRequired("CodeSize", Lines.CodeSize);
+
+  IO.mapRequired("Flags", Lines.Flags);
+  IO.mapRequired("RelocOffset", Lines.RelocOffset);
+  IO.mapRequired("RelocSegment", Lines.RelocSegment);
+  IO.mapRequired("Blocks", Lines.Blocks);
+}
+
+void YAMLInlineeLinesSubsection::map(IO &IO) {
+  IO.mapTag("!InlineeLines", true);
+  IO.mapRequired("HasExtraFiles", InlineeLines.HasExtraFiles);
+  IO.mapRequired("Sites", InlineeLines.Sites);
+}
+
+void MappingTraits<YAMLDebugSubsection>::mapping(
+    IO &IO, YAMLDebugSubsection &Subsection) {
+  if (!IO.outputting()) {
+    if (IO.mapTag("!FileChecksums")) {
+      auto SS = std::make_shared<YAMLChecksumsSubsection>();
+      Subsection.Subsection = SS;
+    } else if (IO.mapTag("!Lines")) {
+      Subsection.Subsection = std::make_shared<YAMLLinesSubsection>();
+    } else if (IO.mapTag("!InlineeLines")) {
+      Subsection.Subsection = std::make_shared<YAMLInlineeLinesSubsection>();
+    } else {
+      llvm_unreachable("Unexpected subsection tag!");
+    }
+  }
+  Subsection.Subsection->map(IO);
+}
+
+static Expected<const YAMLChecksumsSubsection &>
+findChecksums(ArrayRef<YAMLDebugSubsection> Subsections) {
+  for (const auto &SS : Subsections) {
+    if (SS.Subsection->Kind == DebugSubsectionKind::FileChecksums) {
+      return static_cast<const YAMLChecksumsSubsection &>(*SS.Subsection);
+    }
+  }
+  return make_error<CodeViewError>(cv_error_code::no_records);
+}
+
+std::unique_ptr<DebugSubsection> YAMLChecksumsSubsection::toCodeViewSubsection(
+    DebugStringTableSubsection *UseStrings,
+    DebugChecksumsSubsection *UseChecksums) const {
+  assert(UseStrings && !UseChecksums);
+  auto Result = llvm::make_unique<DebugChecksumsSubsection>(*UseStrings);
+  for (const auto &CS : Checksums) {
+    Result->addChecksum(CS.FileName, CS.Kind, CS.ChecksumBytes.Bytes);
+  }
+  return std::move(Result);
+}
+
+std::unique_ptr<DebugSubsection> YAMLLinesSubsection::toCodeViewSubsection(
+    DebugStringTableSubsection *UseStrings,
+    DebugChecksumsSubsection *UseChecksums) const {
+  assert(UseStrings && UseChecksums);
+  auto Result =
+      llvm::make_unique<DebugLinesSubsection>(*UseChecksums, *UseStrings);
+  Result->setCodeSize(Lines.CodeSize);
+  Result->setRelocationAddress(Lines.RelocSegment, Lines.RelocOffset);
+  Result->setFlags(Lines.Flags);
+  for (const auto &LC : Lines.Blocks) {
+    Result->createBlock(LC.FileName);
+    if (Result->hasColumnInfo()) {
+      for (const auto &Item : zip(LC.Lines, LC.Columns)) {
+        auto &L = std::get<0>(Item);
+        auto &C = std::get<1>(Item);
+        uint32_t LE = L.LineStart + L.EndDelta;
+        Result->addLineAndColumnInfo(L.Offset,
+                                     LineInfo(L.LineStart, LE, L.IsStatement),
+                                     C.StartColumn, C.EndColumn);
+      }
+    } else {
+      for (const auto &L : LC.Lines) {
+        uint32_t LE = L.LineStart + L.EndDelta;
+        Result->addLineInfo(L.Offset, LineInfo(L.LineStart, LE, L.IsStatement));
+      }
+    }
+  }
+  return Result;
+}
+
+std::unique_ptr<DebugSubsection>
+YAMLInlineeLinesSubsection::toCodeViewSubsection(
+    DebugStringTableSubsection *UseStrings,
+    DebugChecksumsSubsection *UseChecksums) const {
+  assert(UseChecksums);
+  auto Result = llvm::make_unique<DebugInlineeLinesSubsection>(
+      *UseChecksums, InlineeLines.HasExtraFiles);
+
+  for (const auto &Site : InlineeLines.Sites) {
+    Result->addInlineSite(TypeIndex(Site.Inlinee), Site.FileName,
+                          Site.SourceLineNum);
+    if (!InlineeLines.HasExtraFiles)
+      continue;
+
+    for (auto EF : Site.ExtraFiles) {
+      Result->addExtraFile(EF);
+    }
+  }
+  return Result;
+}
+
+static Expected<SourceFileChecksumEntry>
+convertOneChecksum(const DebugStringTableSubsectionRef &Strings,
+                   const FileChecksumEntry &CS) {
+  auto ExpectedString = Strings.getString(CS.FileNameOffset);
+  if (!ExpectedString)
+    return ExpectedString.takeError();
+
+  SourceFileChecksumEntry Result;
+  Result.ChecksumBytes.Bytes = CS.Checksum;
+  Result.Kind = CS.Kind;
+  Result.FileName = *ExpectedString;
+  return Result;
+}
+
+static Expected<StringRef>
+getFileName(const DebugStringTableSubsectionRef &Strings,
+            const DebugChecksumsSubsectionRef &Checksums, uint32_t FileID) {
+  auto Iter = Checksums.getArray().at(FileID);
+  if (Iter == Checksums.getArray().end())
+    return make_error<CodeViewError>(cv_error_code::no_records);
+  uint32_t Offset = Iter->FileNameOffset;
+  return Strings.getString(Offset);
+}
+
+Expected<std::shared_ptr<YAMLChecksumsSubsection>>
+YAMLChecksumsSubsection::fromCodeViewSubsection(
+    const DebugStringTableSubsectionRef &Strings,
+    const DebugChecksumsSubsectionRef &FC) {
+  auto Result = std::make_shared<YAMLChecksumsSubsection>();
+
+  for (const auto &CS : FC) {
+    auto ConvertedCS = convertOneChecksum(Strings, CS);
+    if (!ConvertedCS)
+      return ConvertedCS.takeError();
+    Result->Checksums.push_back(*ConvertedCS);
+  }
+  return Result;
+}
+
+Expected<std::shared_ptr<YAMLLinesSubsection>>
+YAMLLinesSubsection::fromCodeViewSubsection(
+    const DebugStringTableSubsectionRef &Strings,
+    const DebugChecksumsSubsectionRef &Checksums,
+    const DebugLinesSubsectionRef &Lines) {
+  auto Result = std::make_shared<YAMLLinesSubsection>();
+  Result->Lines.CodeSize = Lines.header()->CodeSize;
+  Result->Lines.RelocOffset = Lines.header()->RelocOffset;
+  Result->Lines.RelocSegment = Lines.header()->RelocSegment;
+  Result->Lines.Flags = static_cast<LineFlags>(uint16_t(Lines.header()->Flags));
+  for (const auto &L : Lines) {
+    SourceLineBlock Block;
+    auto EF = getFileName(Strings, Checksums, L.NameIndex);
+    if (!EF)
+      return EF.takeError();
+    Block.FileName = *EF;
+    if (Lines.hasColumnInfo()) {
+      for (const auto &C : L.Columns) {
+        SourceColumnEntry SCE;
+        SCE.EndColumn = C.EndColumn;
+        SCE.StartColumn = C.StartColumn;
+        Block.Columns.push_back(SCE);
+      }
+    }
+    for (const auto &LN : L.LineNumbers) {
+      SourceLineEntry SLE;
+      LineInfo LI(LN.Flags);
+      SLE.Offset = LN.Offset;
+      SLE.LineStart = LI.getStartLine();
+      SLE.EndDelta = LI.getLineDelta();
+      SLE.IsStatement = LI.isStatement();
+      Block.Lines.push_back(SLE);
+    }
+    Result->Lines.Blocks.push_back(Block);
+  }
+  return Result;
+}
+
+Expected<std::shared_ptr<YAMLInlineeLinesSubsection>>
+YAMLInlineeLinesSubsection::fromCodeViewSubsection(
+    const DebugStringTableSubsectionRef &Strings,
+    const DebugChecksumsSubsectionRef &Checksums,
+    const DebugInlineeLinesSubsectionRef &Lines) {
+  auto Result = std::make_shared<YAMLInlineeLinesSubsection>();
+
+  Result->InlineeLines.HasExtraFiles = Lines.hasExtraFiles();
+  for (const auto &IL : Lines) {
+    InlineeSite Site;
+    auto ExpF = getFileName(Strings, Checksums, IL.Header->FileID);
+    if (!ExpF)
+      return ExpF.takeError();
+    Site.FileName = *ExpF;
+    Site.Inlinee = IL.Header->Inlinee.getIndex();
+    Site.SourceLineNum = IL.Header->SourceLineNum;
+    if (Lines.hasExtraFiles()) {
+      for (const auto EF : IL.ExtraFiles) {
+        auto ExpF2 = getFileName(Strings, Checksums, EF);
+        if (!ExpF2)
+          return ExpF2.takeError();
+        Site.ExtraFiles.push_back(*ExpF2);
+      }
+    }
+    Result->InlineeLines.Sites.push_back(Site);
+  }
+  return Result;
+}
+
+Expected<std::vector<std::unique_ptr<DebugSubsection>>>
+llvm::CodeViewYAML::convertSubsectionList(
+    ArrayRef<YAMLDebugSubsection> Subsections,
+    DebugStringTableSubsection &Strings) {
+  std::vector<std::unique_ptr<DebugSubsection>> Result;
+  if (Subsections.empty())
+    return Result;
+
+  auto Checksums = findChecksums(Subsections);
+  if (!Checksums)
+    return Checksums.takeError();
+  auto ChecksumsBase = Checksums->toCodeViewSubsection(&Strings, nullptr);
+  DebugChecksumsSubsection &CS =
+      llvm::cast<DebugChecksumsSubsection>(*ChecksumsBase);
+  for (const auto &SS : Subsections) {
+    // We've already converted the checksums subsection, don't do it
+    // twice.
+    std::unique_ptr<DebugSubsection> CVS;
+    if (SS.Subsection->Kind == DebugSubsectionKind::FileChecksums)
+      CVS = std::move(ChecksumsBase);
+    else
+      CVS = SS.Subsection->toCodeViewSubsection(&Strings, &CS);
+    Result.push_back(std::move(CVS));
+  }
+  return std::move(Result);
+}
+
+namespace {
+struct SubsectionConversionVisitor : public DebugSubsectionVisitor {
+  explicit SubsectionConversionVisitor(
+      const DebugStringTableSubsectionRef &Strings,
+      const DebugChecksumsSubsectionRef &Checksums)
+      : Strings(Strings), Checksums(Checksums) {}
+
+  Error visitUnknown(DebugUnknownSubsectionRef &Unknown) override;
+  Error visitLines(DebugLinesSubsectionRef &Lines) override;
+  Error visitFileChecksums(DebugChecksumsSubsectionRef &Checksums) override;
+  Error visitInlineeLines(DebugInlineeLinesSubsectionRef &Inlinees) override;
+
+  YAMLDebugSubsection Subsection;
+
+private:
+  const DebugStringTableSubsectionRef &Strings;
+  const DebugChecksumsSubsectionRef &Checksums;
+};
+
+Error SubsectionConversionVisitor::visitUnknown(
+    DebugUnknownSubsectionRef &Unknown) {
+  return make_error<CodeViewError>(cv_error_code::operation_unsupported);
+}
+
+Error SubsectionConversionVisitor::visitLines(DebugLinesSubsectionRef &Lines) {
+  auto Result =
+      YAMLLinesSubsection::fromCodeViewSubsection(Strings, Checksums, Lines);
+  if (!Result)
+    return Result.takeError();
+  Subsection.Subsection = *Result;
+  return Error::success();
+}
+
+Error SubsectionConversionVisitor::visitFileChecksums(
+    DebugChecksumsSubsectionRef &Checksums) {
+  auto Result =
+      YAMLChecksumsSubsection::fromCodeViewSubsection(Strings, Checksums);
+  if (!Result)
+    return Result.takeError();
+  Subsection.Subsection = *Result;
+  return Error::success();
+}
+
+Error SubsectionConversionVisitor::visitInlineeLines(
+    DebugInlineeLinesSubsectionRef &Inlinees) {
+  auto Result = YAMLInlineeLinesSubsection::fromCodeViewSubsection(
+      Strings, Checksums, Inlinees);
+  if (!Result)
+    return Result.takeError();
+  Subsection.Subsection = *Result;
+  return Error::success();
+}
+}
+
+Expected<YAMLDebugSubsection> YAMLDebugSubsection::fromCodeViewSubection(
+    const DebugStringTableSubsectionRef &Strings,
+    const DebugChecksumsSubsectionRef &Checksums,
+    const DebugSubsectionRecord &SS) {
+  SubsectionConversionVisitor V(Strings, Checksums);
+  if (auto EC = visitDebugSubsection(SS, V))
+    return std::move(EC);
+
+  return V.Subsection;
 }
diff --git a/llvm/test/DebugInfo/PDB/Inputs/simple-line-info.yaml b/llvm/test/DebugInfo/PDB/Inputs/simple-line-info.yaml
index 66030020f8f..d1324d26d8b 100644
--- a/llvm/test/DebugInfo/PDB/Inputs/simple-line-info.yaml
+++ b/llvm/test/DebugInfo/PDB/Inputs/simple-line-info.yaml
@@ -5,39 +5,40 @@ DbiStream:
       ObjFile:         'd:\src\llvm\test\DebugInfo\PDB\Inputs\empty.obj'
       SourceFiles:
         - 'd:\src\llvm\test\debuginfo\pdb\inputs\empty.cpp'
-      LineInfo:
-        Checksums:
-          - FileName:        'd:\src\llvm\test\debuginfo\pdb\inputs\empty.cpp'
-            Kind:            MD5
-            Checksum:        A0A5BD0D3ECD93FC29D19DE826FBF4BC
-          - FileName:        'f:\dd\externalapis\windows\10\sdk\inc\winerror.h'
-            Kind:            MD5
-            Checksum:        1154D69F5B2650196E1FC34F4134E56B
-        Lines:
-          - CodeSize:        10
-            Flags:           [  ]
-            RelocOffset:     16
-            RelocSegment:    1
-            Blocks:
-              - FileName:        'd:\src\llvm\test\debuginfo\pdb\inputs\empty.cpp'
-                Lines:
-                  - Offset:          0
-                    LineStart:       5
-                    IsStatement:     true
-                    EndDelta:        0
-                  - Offset:          3
-                    LineStart:       6
-                    IsStatement:     true
-                    EndDelta:        0
-                  - Offset:          8
-                    LineStart:       7
-                    IsStatement:     true
-                    EndDelta:        0
-                Columns:
-        InlineeLines:    
-          - HasExtraFiles:   false
-            Sites:           
-              - FileName:        'f:\dd\externalapis\windows\10\sdk\inc\winerror.h'
-                LineNum:         26950
-                Inlinee:         22767
+      Subsections:
+        - !FileChecksums
+          Checksums:
+            - FileName:        'd:\src\llvm\test\debuginfo\pdb\inputs\empty.cpp'
+              Kind:            MD5
+              Checksum:        A0A5BD0D3ECD93FC29D19DE826FBF4BC
+            - FileName:        'f:\dd\externalapis\windows\10\sdk\inc\winerror.h'
+              Kind:            MD5
+              Checksum:        1154D69F5B2650196E1FC34F4134E56B
+        - !Lines
+          CodeSize:        10
+          Flags:           [  ]
+          RelocOffset:     16
+          RelocSegment:    1
+          Blocks:
+            - FileName:        'd:\src\llvm\test\debuginfo\pdb\inputs\empty.cpp'
+              Lines:
+                - Offset:          0
+                  LineStart:       5
+                  IsStatement:     true
+                  EndDelta:        0
+                - Offset:          3
+                  LineStart:       6
+                  IsStatement:     true
+                  EndDelta:        0
+                - Offset:          8
+                  LineStart:       7
+                  IsStatement:     true
+                  EndDelta:        0
+              Columns:
+        - !InlineeLines
+          HasExtraFiles:   false
+          Sites:           
+            - FileName:        'f:\dd\externalapis\windows\10\sdk\inc\winerror.h'
+              LineNum:         26950
+              Inlinee:         22767
 ...
diff --git a/llvm/test/DebugInfo/PDB/pdbdump-yaml-lineinfo.test b/llvm/test/DebugInfo/PDB/pdbdump-yaml-lineinfo.test
index ca7427c0099..f959805c747 100644
--- a/llvm/test/DebugInfo/PDB/pdbdump-yaml-lineinfo.test
+++ b/llvm/test/DebugInfo/PDB/pdbdump-yaml-lineinfo.test
@@ -28,12 +28,8 @@ YAML:   - Module:          'd:\src\llvm\test\DebugInfo\PDB\Inputs\empty.obj'
 YAML:     ObjFile:         'd:\src\llvm\test\DebugInfo\PDB\Inputs\empty.obj'
 YAML:     SourceFiles:
 YAML:       - 'd:\src\llvm\test\debuginfo\pdb\inputs\empty.cpp'
-YAML:     LineInfo:
-YAML:       Checksums:
-YAML:         - FileName:        'd:\src\llvm\test\debuginfo\pdb\inputs\empty.cpp'
-YAML:           Kind:            MD5
-YAML:           Checksum:        A0A5BD0D3ECD93FC29D19DE826FBF4BC
-YAML:       Lines:
+YAML:     Subsections:
+YAML:       - !Lines
 YAML:         CodeSize:        10
 YAML:         Flags:           [  ]
 YAML:         RelocOffset:     16
@@ -54,6 +50,11 @@ YAML:                 LineStart:       7
 YAML:                 IsStatement:     true
 YAML:                 EndDelta:        0
 YAML:             Columns:
+YAML:       - !FileChecksums
+YAML:         Checksums:
+YAML:           - FileName:        'd:\src\llvm\test\debuginfo\pdb\inputs\empty.cpp'
+YAML:             Kind:            MD5
+YAML:             Checksum:        A0A5BD0D3ECD93FC29D19DE826FBF4BC
 YAML:  - Module:          '* Linker *'
 YAML:    ObjFile:         ''
 YAML: ...
\ No newline at end of file
diff --git a/llvm/tools/llvm-pdbdump/LLVMOutputStyle.cpp b/llvm/tools/llvm-pdbdump/LLVMOutputStyle.cpp
index 6a9fb25dda3..7268d0b888d 100644
--- a/llvm/tools/llvm-pdbdump/LLVMOutputStyle.cpp
+++ b/llvm/tools/llvm-pdbdump/LLVMOutputStyle.cpp
@@ -831,8 +831,7 @@ Error LLVMOutputStyle::dumpDbiStream() {
             return ExpectedTypes.takeError();
           auto &IpiItems = *ExpectedTypes;
           C13RawVisitor V(P, File, IpiItems);
-          if (auto EC =
-                  codeview::visitDebugSubsections(ModS.linesAndChecksums(), V))
+          if (auto EC = codeview::visitDebugSubsections(ModS.subsections(), V))
             return EC;
         }
       }
diff --git a/llvm/tools/llvm-pdbdump/PdbYaml.cpp b/llvm/tools/llvm-pdbdump/PdbYaml.cpp
index e288063e2af..b4a41fbfdb8 100644
--- a/llvm/tools/llvm-pdbdump/PdbYaml.cpp
+++ b/llvm/tools/llvm-pdbdump/PdbYaml.cpp
@@ -12,6 +12,7 @@
 #include "llvm/ADT/StringExtras.h"
 #include "llvm/DebugInfo/CodeView/CVSymbolVisitor.h"
 #include "llvm/DebugInfo/CodeView/CVTypeVisitor.h"
+#include "llvm/DebugInfo/CodeView/DebugStringTableSubsection.h"
 #include "llvm/DebugInfo/CodeView/SymbolDeserializer.h"
 #include "llvm/DebugInfo/CodeView/SymbolVisitorCallbackPipeline.h"
 #include "llvm/DebugInfo/CodeView/TypeSerializer.h"
@@ -21,6 +22,7 @@
 #include "llvm/DebugInfo/PDB/Native/TpiHashing.h"
 #include "llvm/DebugInfo/PDB/PDBExtras.h"
 #include "llvm/DebugInfo/PDB/PDBTypes.h"
+#include "llvm/ObjectYAML/CodeViewYAMLDebugSections.h"
 #include "llvm/ObjectYAML/CodeViewYAMLTypes.h"
 
 using namespace llvm;
@@ -220,6 +222,6 @@ void MappingTraits<PdbDbiModuleInfo>::mapping(IO &IO, PdbDbiModuleInfo &Obj) {
   IO.mapRequired("Module", Obj.Mod);
   IO.mapOptional("ObjFile", Obj.Obj, Obj.Mod);
   IO.mapOptional("SourceFiles", Obj.SourceFiles);
-  IO.mapOptional("LineInfo", Obj.FileLineInfo);
+  IO.mapOptional("Subsections", Obj.Subsections);
   IO.mapOptional("Modi", Obj.Modi);
 }
diff --git a/llvm/tools/llvm-pdbdump/PdbYaml.h b/llvm/tools/llvm-pdbdump/PdbYaml.h
index deb500ec207..62ed608916f 100644
--- a/llvm/tools/llvm-pdbdump/PdbYaml.h
+++ b/llvm/tools/llvm-pdbdump/PdbYaml.h
@@ -28,6 +28,9 @@
 #include <vector>
 
 namespace llvm {
+namespace codeview {
+class DebugStringTableSubsection;
+}
 namespace pdb {
 
 namespace yaml {
@@ -68,7 +71,7 @@ struct PdbDbiModuleInfo {
   StringRef Obj;
   StringRef Mod;
   std::vector<StringRef> SourceFiles;
-  Optional<CodeViewYAML::SourceFileInfo> FileLineInfo;
+  std::vector<CodeViewYAML::YAMLDebugSubsection> Subsections;
   Optional<PdbModiStream> Modi;
 };
 
diff --git a/llvm/tools/llvm-pdbdump/YAMLOutputStyle.cpp b/llvm/tools/llvm-pdbdump/YAMLOutputStyle.cpp
index 18839a7679d..610b288c9ba 100644
--- a/llvm/tools/llvm-pdbdump/YAMLOutputStyle.cpp
+++ b/llvm/tools/llvm-pdbdump/YAMLOutputStyle.cpp
@@ -101,117 +101,6 @@ Error YAMLOutputStyle::dump() {
   return Error::success();
 }
 
-namespace {
-class C13YamlVisitor : public C13DebugFragmentVisitor {
-public:
-  C13YamlVisitor(CodeViewYAML::SourceFileInfo &Info, PDBFile &F)
-      : C13DebugFragmentVisitor(F), Info(Info) {}
-
-  Error handleFileChecksums() override {
-    for (const auto &C : *Checksums) {
-      CodeViewYAML::SourceFileChecksumEntry Entry;
-      if (auto Result = getNameFromStringTable(C.FileNameOffset))
-        Entry.FileName = *Result;
-      else
-        return Result.takeError();
-
-      Entry.Kind = C.Kind;
-      Entry.ChecksumBytes.Bytes = C.Checksum;
-      Info.FileChecksums.push_back(Entry);
-    }
-    return Error::success();
-  }
-
-  Error handleLines() override {
-    for (const auto &LF : Lines) {
-      Info.LineFragments.emplace_back();
-      auto &Fragment = Info.LineFragments.back();
-
-      Fragment.CodeSize = LF.header()->CodeSize;
-      Fragment.Flags =
-          static_cast<codeview::LineFlags>(uint16_t(LF.header()->Flags));
-      Fragment.RelocOffset = LF.header()->RelocOffset;
-      Fragment.RelocSegment = LF.header()->RelocSegment;
-
-      for (const auto &L : LF) {
-        Fragment.Blocks.emplace_back();
-        auto &Block = Fragment.Blocks.back();
-
-        if (auto Result = getNameFromChecksumsBuffer(L.NameIndex))
-          Block.FileName = *Result;
-        else
-          return Result.takeError();
-
-        for (const auto &N : L.LineNumbers) {
-          CodeViewYAML::SourceLineEntry Line;
-          Line.Offset = N.Offset;
-          codeview::LineInfo LI(N.Flags);
-          Line.LineStart = LI.getStartLine();
-          Line.EndDelta = LI.getLineDelta();
-          Line.IsStatement = LI.isStatement();
-          Block.Lines.push_back(Line);
-        }
-
-        if (LF.hasColumnInfo()) {
-          for (const auto &C : L.Columns) {
-            CodeViewYAML::SourceColumnEntry Column;
-            Column.StartColumn = C.StartColumn;
-            Column.EndColumn = C.EndColumn;
-            Block.Columns.push_back(Column);
-          }
-        }
-      }
-    }
-    return Error::success();
-  }
-
-  Error handleInlineeLines() override {
-    for (const auto &ILF : InlineeLines) {
-      Info.Inlinees.emplace_back();
-      auto &Inlinee = Info.Inlinees.back();
-
-      Inlinee.HasExtraFiles = ILF.hasExtraFiles();
-      for (const auto &IL : ILF) {
-        Inlinee.Sites.emplace_back();
-        auto &Site = Inlinee.Sites.back();
-        if (auto Result = getNameFromChecksumsBuffer(IL.Header->FileID))
-          Site.FileName = *Result;
-        else
-          return Result.takeError();
-
-        Site.Inlinee = IL.Header->Inlinee.getIndex();
-        Site.SourceLineNum = IL.Header->SourceLineNum;
-        if (ILF.hasExtraFiles()) {
-          for (const auto &EF : IL.ExtraFiles) {
-            if (auto Result = getNameFromChecksumsBuffer(EF))
-              Site.ExtraFiles.push_back(*Result);
-            else
-              return Result.takeError();
-          }
-        }
-      }
-    }
-    return Error::success();
-  }
-
-private:
-  CodeViewYAML::SourceFileInfo &Info;
-};
-}
-
-Expected<Optional<CodeViewYAML::SourceFileInfo>>
-YAMLOutputStyle::getFileLineInfo(const pdb::ModuleDebugStreamRef &ModS) {
-  if (!ModS.hasLineInfo())
-    return None;
-
-  CodeViewYAML::SourceFileInfo Info;
-  C13YamlVisitor Visitor(Info, File);
-  if (auto EC =
-          codeview::visitDebugSubsections(ModS.linesAndChecksums(), Visitor))
-    return std::move(EC);
-
-  return Info;
-}
 
 Error YAMLOutputStyle::dumpFileHeaders() {
   if (opts::pdb2yaml::NoFileHeaders)
@@ -236,14 +125,17 @@ Error YAMLOutputStyle::dumpFileHeaders() {
 }
 
 Error YAMLOutputStyle::dumpStringTable() {
-  if (!opts::pdb2yaml::StringTable)
+  bool RequiresStringTable = opts::pdb2yaml::DbiModuleSourceFileInfo ||
+                             opts::pdb2yaml::DbiModuleSourceLineInfo;
+  bool RequestedStringTable = opts::pdb2yaml::StringTable;
+  if (!RequiresStringTable && !RequestedStringTable)
     return Error::success();
 
-  Obj.StringTable.emplace();
   auto ExpectedST = File.getStringTable();
   if (!ExpectedST)
     return ExpectedST.takeError();
 
+  Obj.StringTable.emplace();
   const auto &ST = ExpectedST.get();
   for (auto ID : ST.name_ids()) {
     auto S = ST.getStringForID(ID);
@@ -343,11 +235,23 @@ Error YAMLOutputStyle::dumpDbiStream() {
       if (auto EC = ModS.reload())
         return EC;
 
-      if (opts::pdb2yaml::DbiModuleSourceLineInfo) {
-        auto ExpectedInfo = getFileLineInfo(ModS);
-        if (!ExpectedInfo)
-          return ExpectedInfo.takeError();
-        DMI.FileLineInfo = *ExpectedInfo;
+      auto ExpectedST = File.getStringTable();
+      if (!ExpectedST)
+        return ExpectedST.takeError();
+      if (opts::pdb2yaml::DbiModuleSourceLineInfo &&
+          ModS.hasDebugSubsections()) {
+        auto ExpectedChecksums = ModS.findChecksumsSubsection();
+        if (!ExpectedChecksums)
+          return ExpectedChecksums.takeError();
+
+        for (const auto &SS : ModS.subsections()) {
+          auto Converted =
+              CodeViewYAML::YAMLDebugSubsection::fromCodeViewSubection(
+                  ExpectedST->getStringTable(), *ExpectedChecksums, SS);
+          if (!Converted)
+            return Converted.takeError();
+          DMI.Subsections.push_back(*Converted);
+        }
       }
 
       if (opts::pdb2yaml::DbiModuleSyms) {
diff --git a/llvm/tools/llvm-pdbdump/YAMLOutputStyle.h b/llvm/tools/llvm-pdbdump/YAMLOutputStyle.h
index 6e4067c48f8..3690e3529d4 100644
--- a/llvm/tools/llvm-pdbdump/YAMLOutputStyle.h
+++ b/llvm/tools/llvm-pdbdump/YAMLOutputStyle.h
@@ -27,9 +27,6 @@ public:
   Error dump() override;
 
 private:
-  Expected<Optional<CodeViewYAML::SourceFileInfo>>
-  getFileLineInfo(const pdb::ModuleDebugStreamRef &ModS);
-
   Error dumpStringTable();
   Error dumpFileHeaders();
   Error dumpStreamMetadata();
diff --git a/llvm/tools/llvm-pdbdump/llvm-pdbdump.cpp b/llvm/tools/llvm-pdbdump/llvm-pdbdump.cpp
index 7534790254d..4626de9c444 100644
--- a/llvm/tools/llvm-pdbdump/llvm-pdbdump.cpp
+++ b/llvm/tools/llvm-pdbdump/llvm-pdbdump.cpp
@@ -476,7 +476,6 @@ static void yamlToPdb(StringRef Path) {
   std::unique_ptr<MemoryBuffer> &Buffer = ErrorOrBuffer.get();
 
   llvm::yaml::Input In(Buffer->getBuffer());
-  In.setContext(&Allocator);
   pdb::yaml::PdbObject YamlObj(Allocator);
   In >> YamlObj;
 
@@ -540,64 +539,11 @@ static void yamlToPdb(StringRef Path) {
             Symbol.toCodeViewSymbol(Allocator, CodeViewContainer::Pdb));
       }
     }
-    if (MI.FileLineInfo.hasValue()) {
-      const auto &FLI = *MI.FileLineInfo;
-
-      // File Checksums must be emitted before line information, because line
-      // info records use offsets into the checksum buffer to reference a file's
-      // source file name.
-      auto Checksums = llvm::make_unique<DebugChecksumsSubsection>(Strings);
-      auto &ChecksumRef = *Checksums;
-      if (!FLI.FileChecksums.empty()) {
-        for (auto &FC : FLI.FileChecksums)
-          Checksums->addChecksum(FC.FileName, FC.Kind, FC.ChecksumBytes.Bytes);
-      }
-      ModiBuilder.setC13FileChecksums(std::move(Checksums));
-
-      for (const auto &Fragment : FLI.LineFragments) {
-        auto Lines =
-            llvm::make_unique<DebugLinesSubsection>(ChecksumRef, Strings);
-        Lines->setCodeSize(Fragment.CodeSize);
-        Lines->setRelocationAddress(Fragment.RelocSegment,
-                                    Fragment.RelocOffset);
-        Lines->setFlags(Fragment.Flags);
-        for (const auto &LC : Fragment.Blocks) {
-          Lines->createBlock(LC.FileName);
-          if (Lines->hasColumnInfo()) {
-            for (const auto &Item : zip(LC.Lines, LC.Columns)) {
-              auto &L = std::get<0>(Item);
-              auto &C = std::get<1>(Item);
-              uint32_t LE = L.LineStart + L.EndDelta;
-              Lines->addLineAndColumnInfo(
-                  L.Offset, LineInfo(L.LineStart, LE, L.IsStatement),
-                  C.StartColumn, C.EndColumn);
-            }
-          } else {
-            for (const auto &L : LC.Lines) {
-              uint32_t LE = L.LineStart + L.EndDelta;
-              Lines->addLineInfo(L.Offset,
-                                 LineInfo(L.LineStart, LE, L.IsStatement));
-            }
-          }
-        }
-        ModiBuilder.addC13Fragment(std::move(Lines));
-      }
 
-      for (const auto &Inlinee : FLI.Inlinees) {
-        auto Inlinees = llvm::make_unique<DebugInlineeLinesSubsection>(
-            ChecksumRef, Inlinee.HasExtraFiles);
-        for (const auto &Site : Inlinee.Sites) {
-          Inlinees->addInlineSite(TypeIndex(Site.Inlinee), Site.FileName,
-                                  Site.SourceLineNum);
-          if (!Inlinee.HasExtraFiles)
-            continue;
-
-          for (auto EF : Site.ExtraFiles) {
-            Inlinees->addExtraFile(EF);
-          }
-        }
-        ModiBuilder.addC13Fragment(std::move(Inlinees));
-      }
+    auto CodeViewSubsections =
+        ExitOnErr(CodeViewYAML::convertSubsectionList(MI.Subsections, Strings));
+    for (auto &SS : CodeViewSubsections) {
+      ModiBuilder.addDebugSubsection(std::move(SS));
     }
   }