Revert "[codeview] Make obj2yaml/yaml2obj support .debug$S..."

This is causing failures on linux bots with an invalid stream
read.  It doesn't repro in any configuration on Windows, so
reverting until I have a chance to investigate on Linux.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@305371 91177308-0d34-0410-b5e6-96231b3b80d8

3 files changed, 168 insertions, 210 deletions

diff --git a/lib/ObjectYAML/COFFYAML.cpp b/lib/ObjectYAML/COFFYAML.cpp
index c8cbea1490f..7f9f4c1f8c2 100644
--- a/lib/ObjectYAML/COFFYAML.cpp
+++ b/lib/ObjectYAML/COFFYAML.cpp
@@ -488,16 +488,7 @@ void MappingTraits<COFFYAML::Section>::mapping(IO &IO, COFFYAML::Section &Sec) {
   IO.mapOptional("VirtualAddress", Sec.Header.VirtualAddress, 0U);
   IO.mapOptional("VirtualSize", Sec.Header.VirtualSize, 0U);
   IO.mapOptional("Alignment", Sec.Alignment, 0U);
-
-  // If this is a .debug$S or .debug$T section parse the semantic representation
-  // of the symbols/types.  If it is any other kind of section, just deal in raw
-  // bytes.
-  IO.mapOptional("SectionData", Sec.SectionData);
-  if (Sec.Name == ".debug$S")
-    IO.mapOptional("Subsections", Sec.DebugS);
-  else if (Sec.Name == ".debug$T")
-    IO.mapOptional("Types", Sec.DebugT);
-
+  IO.mapRequired("SectionData", Sec.SectionData);
   IO.mapOptional("Relocations", Sec.Relocations);
 }
 
diff --git a/lib/ObjectYAML/CodeViewYAMLDebugSections.cpp b/lib/ObjectYAML/CodeViewYAMLDebugSections.cpp
index 728079a2a6b..08a4bb715fa 100644
--- a/lib/ObjectYAML/CodeViewYAMLDebugSections.cpp
+++ b/lib/ObjectYAML/CodeViewYAMLDebugSections.cpp
@@ -28,7 +28,6 @@
 #include "llvm/DebugInfo/CodeView/DebugSymbolRVASubsection.h"
 #include "llvm/DebugInfo/CodeView/DebugSymbolsSubsection.h"
 #include "llvm/DebugInfo/CodeView/EnumTables.h"
-#include "llvm/DebugInfo/CodeView/StringsAndChecksums.h"
 #include "llvm/DebugInfo/CodeView/SymbolRecord.h"
 #include "llvm/DebugInfo/CodeView/SymbolSerializer.h"
 #include "llvm/ObjectYAML/CodeViewYAMLSymbols.h"
@@ -76,9 +75,10 @@ struct YAMLSubsectionBase {
   virtual ~YAMLSubsectionBase() {}
 
   virtual void map(IO &IO) = 0;
-  virtual std::shared_ptr<DebugSubsection>
+  virtual std::unique_ptr<DebugSubsection>
   toCodeViewSubsection(BumpPtrAllocator &Allocator,
-                       const codeview::StringsAndChecksums &SC) const = 0;
+                       DebugStringTableSubsection *UseStrings,
+                       DebugChecksumsSubsection *UseChecksums) const = 0;
 };
 }
 }
@@ -90,9 +90,10 @@ struct YAMLChecksumsSubsection : public YAMLSubsectionBase {
       : YAMLSubsectionBase(DebugSubsectionKind::FileChecksums) {}
 
   void map(IO &IO) override;
-  std::shared_ptr<DebugSubsection>
+  std::unique_ptr<DebugSubsection>
   toCodeViewSubsection(BumpPtrAllocator &Allocator,
-                       const codeview::StringsAndChecksums &SC) const override;
+                       DebugStringTableSubsection *Strings,
+                       DebugChecksumsSubsection *Checksums) const override;
   static Expected<std::shared_ptr<YAMLChecksumsSubsection>>
   fromCodeViewSubsection(const DebugStringTableSubsectionRef &Strings,
                          const DebugChecksumsSubsectionRef &FC);
@@ -104,9 +105,10 @@ struct YAMLLinesSubsection : public YAMLSubsectionBase {
   YAMLLinesSubsection() : YAMLSubsectionBase(DebugSubsectionKind::Lines) {}
 
   void map(IO &IO) override;
-  std::shared_ptr<DebugSubsection>
+  std::unique_ptr<DebugSubsection>
   toCodeViewSubsection(BumpPtrAllocator &Allocator,
-                       const codeview::StringsAndChecksums &SC) const override;
+                       DebugStringTableSubsection *Strings,
+                       DebugChecksumsSubsection *Checksums) const override;
   static Expected<std::shared_ptr<YAMLLinesSubsection>>
   fromCodeViewSubsection(const DebugStringTableSubsectionRef &Strings,
                          const DebugChecksumsSubsectionRef &Checksums,
@@ -120,9 +122,10 @@ struct YAMLInlineeLinesSubsection : public YAMLSubsectionBase {
       : YAMLSubsectionBase(DebugSubsectionKind::InlineeLines) {}
 
   void map(IO &IO) override;
-  std::shared_ptr<DebugSubsection>
+  std::unique_ptr<DebugSubsection>
   toCodeViewSubsection(BumpPtrAllocator &Allocator,
-                       const codeview::StringsAndChecksums &SC) const override;
+                       DebugStringTableSubsection *Strings,
+                       DebugChecksumsSubsection *Checksums) const override;
   static Expected<std::shared_ptr<YAMLInlineeLinesSubsection>>
   fromCodeViewSubsection(const DebugStringTableSubsectionRef &Strings,
                          const DebugChecksumsSubsectionRef &Checksums,
@@ -136,9 +139,10 @@ struct YAMLCrossModuleExportsSubsection : public YAMLSubsectionBase {
       : YAMLSubsectionBase(DebugSubsectionKind::CrossScopeExports) {}
 
   void map(IO &IO) override;
-  std::shared_ptr<DebugSubsection>
+  std::unique_ptr<DebugSubsection>
   toCodeViewSubsection(BumpPtrAllocator &Allocator,
-                       const codeview::StringsAndChecksums &SC) const override;
+                       DebugStringTableSubsection *Strings,
+                       DebugChecksumsSubsection *Checksums) const override;
   static Expected<std::shared_ptr<YAMLCrossModuleExportsSubsection>>
   fromCodeViewSubsection(const DebugCrossModuleExportsSubsectionRef &Exports);
 
@@ -150,9 +154,10 @@ struct YAMLCrossModuleImportsSubsection : public YAMLSubsectionBase {
       : YAMLSubsectionBase(DebugSubsectionKind::CrossScopeImports) {}
 
   void map(IO &IO) override;
-  std::shared_ptr<DebugSubsection>
+  std::unique_ptr<DebugSubsection>
   toCodeViewSubsection(BumpPtrAllocator &Allocator,
-                       const codeview::StringsAndChecksums &SC) const override;
+                       DebugStringTableSubsection *Strings,
+                       DebugChecksumsSubsection *Checksums) const override;
   static Expected<std::shared_ptr<YAMLCrossModuleImportsSubsection>>
   fromCodeViewSubsection(const DebugStringTableSubsectionRef &Strings,
                          const DebugCrossModuleImportsSubsectionRef &Imports);
@@ -164,9 +169,10 @@ struct YAMLSymbolsSubsection : public YAMLSubsectionBase {
   YAMLSymbolsSubsection() : YAMLSubsectionBase(DebugSubsectionKind::Symbols) {}
 
   void map(IO &IO) override;
-  std::shared_ptr<DebugSubsection>
+  std::unique_ptr<DebugSubsection>
   toCodeViewSubsection(BumpPtrAllocator &Allocator,
-                       const codeview::StringsAndChecksums &SC) const override;
+                       DebugStringTableSubsection *Strings,
+                       DebugChecksumsSubsection *Checksums) const override;
   static Expected<std::shared_ptr<YAMLSymbolsSubsection>>
   fromCodeViewSubsection(const DebugSymbolsSubsectionRef &Symbols);
 
@@ -178,9 +184,10 @@ struct YAMLStringTableSubsection : public YAMLSubsectionBase {
       : YAMLSubsectionBase(DebugSubsectionKind::StringTable) {}
 
   void map(IO &IO) override;
-  std::shared_ptr<DebugSubsection>
+  std::unique_ptr<DebugSubsection>
   toCodeViewSubsection(BumpPtrAllocator &Allocator,
-                       const codeview::StringsAndChecksums &SC) const override;
+                       DebugStringTableSubsection *Strings,
+                       DebugChecksumsSubsection *Checksums) const override;
   static Expected<std::shared_ptr<YAMLStringTableSubsection>>
   fromCodeViewSubsection(const DebugStringTableSubsectionRef &Strings);
 
@@ -192,9 +199,10 @@ struct YAMLFrameDataSubsection : public YAMLSubsectionBase {
       : YAMLSubsectionBase(DebugSubsectionKind::FrameData) {}
 
   void map(IO &IO) override;
-  std::shared_ptr<DebugSubsection>
+  std::unique_ptr<DebugSubsection>
   toCodeViewSubsection(BumpPtrAllocator &Allocator,
-                       const codeview::StringsAndChecksums &SC) const override;
+                       DebugStringTableSubsection *Strings,
+                       DebugChecksumsSubsection *Checksums) const override;
   static Expected<std::shared_ptr<YAMLFrameDataSubsection>>
   fromCodeViewSubsection(const DebugStringTableSubsectionRef &Strings,
                          const DebugFrameDataSubsectionRef &Frames);
@@ -207,9 +215,10 @@ struct YAMLCoffSymbolRVASubsection : public YAMLSubsectionBase {
       : YAMLSubsectionBase(DebugSubsectionKind::CoffSymbolRVA) {}
 
   void map(IO &IO) override;
-  std::shared_ptr<DebugSubsection>
+  std::unique_ptr<DebugSubsection>
   toCodeViewSubsection(BumpPtrAllocator &Allocator,
-                       const codeview::StringsAndChecksums &SC) const override;
+                       DebugStringTableSubsection *Strings,
+                       DebugChecksumsSubsection *Checksums) const override;
   static Expected<std::shared_ptr<YAMLCoffSymbolRVASubsection>>
   fromCodeViewSubsection(const DebugSymbolRVASubsectionRef &RVAs);
 
@@ -391,23 +400,23 @@ findChecksums(ArrayRef<YAMLDebugSubsection> Subsections) {
   return nullptr;
 }
 
-std::shared_ptr<DebugSubsection> YAMLChecksumsSubsection::toCodeViewSubsection(
-    BumpPtrAllocator &Allocator,
-    const codeview::StringsAndChecksums &SC) const {
-  assert(SC.hasStrings());
-  auto Result = std::make_shared<DebugChecksumsSubsection>(*SC.strings());
+std::unique_ptr<DebugSubsection> YAMLChecksumsSubsection::toCodeViewSubsection(
+    BumpPtrAllocator &Allocator, 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 Result;
+  return std::move(Result);
 }
 
-std::shared_ptr<DebugSubsection> YAMLLinesSubsection::toCodeViewSubsection(
-    BumpPtrAllocator &Allocator,
-    const codeview::StringsAndChecksums &SC) const {
-  assert(SC.hasStrings() && SC.hasChecksums());
+std::unique_ptr<DebugSubsection> YAMLLinesSubsection::toCodeViewSubsection(
+    BumpPtrAllocator &Allocator, DebugStringTableSubsection *UseStrings,
+    DebugChecksumsSubsection *UseChecksums) const {
+  assert(UseStrings && UseChecksums);
   auto Result =
-      std::make_shared<DebugLinesSubsection>(*SC.checksums(), *SC.strings());
+      llvm::make_unique<DebugLinesSubsection>(*UseChecksums, *UseStrings);
   Result->setCodeSize(Lines.CodeSize);
   Result->setRelocationAddress(Lines.RelocSegment, Lines.RelocOffset);
   Result->setFlags(Lines.Flags);
@@ -429,16 +438,16 @@ std::shared_ptr<DebugSubsection> YAMLLinesSubsection::toCodeViewSubsection(
       }
     }
   }
-  return Result;
+  return llvm::cast<DebugSubsection>(std::move(Result));
 }
 
-std::shared_ptr<DebugSubsection>
+std::unique_ptr<DebugSubsection>
 YAMLInlineeLinesSubsection::toCodeViewSubsection(
-    BumpPtrAllocator &Allocator,
-    const codeview::StringsAndChecksums &SC) const {
-  assert(SC.hasChecksums());
-  auto Result = std::make_shared<DebugInlineeLinesSubsection>(
-      *SC.checksums(), InlineeLines.HasExtraFiles);
+    BumpPtrAllocator &Allocator, 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,
@@ -450,60 +459,56 @@ YAMLInlineeLinesSubsection::toCodeViewSubsection(
       Result->addExtraFile(EF);
     }
   }
-  return Result;
+  return llvm::cast<DebugSubsection>(std::move(Result));
 }
 
-std::shared_ptr<DebugSubsection>
+std::unique_ptr<DebugSubsection>
 YAMLCrossModuleExportsSubsection::toCodeViewSubsection(
-    BumpPtrAllocator &Allocator,
-    const codeview::StringsAndChecksums &SC) const {
-  auto Result = std::make_shared<DebugCrossModuleExportsSubsection>();
+    BumpPtrAllocator &Allocator, DebugStringTableSubsection *Strings,
+    DebugChecksumsSubsection *Checksums) const {
+  auto Result = llvm::make_unique<DebugCrossModuleExportsSubsection>();
   for (const auto &M : Exports)
     Result->addMapping(M.Local, M.Global);
-  return Result;
+  return llvm::cast<DebugSubsection>(std::move(Result));
 }
 
-std::shared_ptr<DebugSubsection>
+std::unique_ptr<DebugSubsection>
 YAMLCrossModuleImportsSubsection::toCodeViewSubsection(
-    BumpPtrAllocator &Allocator,
-    const codeview::StringsAndChecksums &SC) const {
-  assert(SC.hasStrings());
-
-  auto Result =
-      std::make_shared<DebugCrossModuleImportsSubsection>(*SC.strings());
+    BumpPtrAllocator &Allocator, DebugStringTableSubsection *Strings,
+    DebugChecksumsSubsection *Checksums) const {
+  auto Result = llvm::make_unique<DebugCrossModuleImportsSubsection>(*Strings);
   for (const auto &M : Imports) {
     for (const auto Id : M.ImportIds)
       Result->addImport(M.ModuleName, Id);
   }
-  return Result;
+  return llvm::cast<DebugSubsection>(std::move(Result));
 }
 
-std::shared_ptr<DebugSubsection> YAMLSymbolsSubsection::toCodeViewSubsection(
-    BumpPtrAllocator &Allocator,
-    const codeview::StringsAndChecksums &SC) const {
-  auto Result = std::make_shared<DebugSymbolsSubsection>();
+std::unique_ptr<DebugSubsection> YAMLSymbolsSubsection::toCodeViewSubsection(
+    BumpPtrAllocator &Allocator, DebugStringTableSubsection *Strings,
+    DebugChecksumsSubsection *Checksums) const {
+  auto Result = llvm::make_unique<DebugSymbolsSubsection>();
   for (const auto &Sym : Symbols)
     Result->addSymbol(
         Sym.toCodeViewSymbol(Allocator, CodeViewContainer::ObjectFile));
-  return Result;
+  return std::move(Result);
 }
 
-std::shared_ptr<DebugSubsection>
+std::unique_ptr<DebugSubsection>
 YAMLStringTableSubsection::toCodeViewSubsection(
-    BumpPtrAllocator &Allocator,
-    const codeview::StringsAndChecksums &SC) const {
-  auto Result = std::make_shared<DebugStringTableSubsection>();
+    BumpPtrAllocator &Allocator, DebugStringTableSubsection *Strings,
+    DebugChecksumsSubsection *Checksums) const {
+  auto Result = llvm::make_unique<DebugStringTableSubsection>();
   for (const auto &Str : this->Strings)
     Result->insert(Str);
-  return Result;
+  return std::move(Result);
 }
 
-std::shared_ptr<DebugSubsection> YAMLFrameDataSubsection::toCodeViewSubsection(
-    BumpPtrAllocator &Allocator,
-    const codeview::StringsAndChecksums &SC) const {
-  assert(SC.hasStrings());
-
-  auto Result = std::make_shared<DebugFrameDataSubsection>();
+std::unique_ptr<DebugSubsection> YAMLFrameDataSubsection::toCodeViewSubsection(
+    BumpPtrAllocator &Allocator, DebugStringTableSubsection *Strings,
+    DebugChecksumsSubsection *Checksums) const {
+  assert(Strings);
+  auto Result = llvm::make_unique<DebugFrameDataSubsection>();
   for (const auto &YF : Frames) {
     codeview::FrameData F;
     F.CodeSize = YF.CodeSize;
@@ -514,20 +519,20 @@ std::shared_ptr<DebugSubsection> YAMLFrameDataSubsection::toCodeViewSubsection(
     F.PrologSize = YF.PrologSize;
     F.RvaStart = YF.RvaStart;
     F.SavedRegsSize = YF.SavedRegsSize;
-    F.FrameFunc = SC.strings()->insert(YF.FrameFunc);
+    F.FrameFunc = Strings->insert(YF.FrameFunc);
     Result->addFrameData(F);
   }
-  return Result;
+  return std::move(Result);
 }
 
-std::shared_ptr<DebugSubsection>
+std::unique_ptr<DebugSubsection>
 YAMLCoffSymbolRVASubsection::toCodeViewSubsection(
-    BumpPtrAllocator &Allocator,
-    const codeview::StringsAndChecksums &SC) const {
-  auto Result = std::make_shared<DebugSymbolRVASubsection>();
+    BumpPtrAllocator &Allocator, DebugStringTableSubsection *Strings,
+    DebugChecksumsSubsection *Checksums) const {
+  auto Result = llvm::make_unique<DebugSymbolRVASubsection>();
   for (const auto &RVA : RVAs)
     Result->addRVA(RVA);
-  return Result;
+  return std::move(Result);
 }
 
 static Expected<SourceFileChecksumEntry>
@@ -736,17 +741,63 @@ YAMLCoffSymbolRVASubsection::fromCodeViewSubsection(
   return Result;
 }
 
-Expected<std::vector<std::shared_ptr<DebugSubsection>>>
+Expected<std::vector<std::unique_ptr<DebugSubsection>>>
+llvm::CodeViewYAML::toCodeViewSubsectionList(
+    BumpPtrAllocator &Allocator, ArrayRef<YAMLDebugSubsection> Subsections,
+    DebugStringTableSubsection &Strings) {
+  std::vector<std::unique_ptr<DebugSubsection>> Result;
+  if (Subsections.empty())
+    return std::move(Result);
+
+  auto Checksums = findChecksums(Subsections);
+  std::unique_ptr<DebugSubsection> ChecksumsBase;
+  if (Checksums)
+    ChecksumsBase =
+        Checksums->toCodeViewSubsection(Allocator, &Strings, nullptr);
+  DebugChecksumsSubsection *CS =
+      static_cast<DebugChecksumsSubsection *>(ChecksumsBase.get());
+  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(Allocator, &Strings, CS);
+    assert(CVS != nullptr);
+    Result.push_back(std::move(CVS));
+  }
+  return std::move(Result);
+}
+
+Expected<std::vector<std::unique_ptr<codeview::DebugSubsection>>>
 llvm::CodeViewYAML::toCodeViewSubsectionList(
     BumpPtrAllocator &Allocator, ArrayRef<YAMLDebugSubsection> Subsections,
-    const codeview::StringsAndChecksums &SC) {
-  std::vector<std::shared_ptr<DebugSubsection>> Result;
+    std::unique_ptr<DebugStringTableSubsection> &TakeStrings,
+    DebugStringTableSubsection *StringsRef) {
+  std::vector<std::unique_ptr<DebugSubsection>> Result;
   if (Subsections.empty())
     return std::move(Result);
 
+  auto Checksums = findChecksums(Subsections);
+
+  std::unique_ptr<DebugSubsection> ChecksumsBase;
+  if (Checksums)
+    ChecksumsBase =
+        Checksums->toCodeViewSubsection(Allocator, StringsRef, nullptr);
+  DebugChecksumsSubsection *CS =
+      static_cast<DebugChecksumsSubsection *>(ChecksumsBase.get());
   for (const auto &SS : Subsections) {
-    std::shared_ptr<DebugSubsection> CVS;
-    CVS = SS.Subsection->toCodeViewSubsection(Allocator, SC);
+    // We've already converted the checksums and string table subsection, don't
+    // do it twice.
+    std::unique_ptr<DebugSubsection> CVS;
+    if (SS.Subsection->Kind == DebugSubsectionKind::FileChecksums)
+      CVS = std::move(ChecksumsBase);
+    else if (SS.Subsection->Kind == DebugSubsectionKind::StringTable) {
+      assert(TakeStrings && "No string table!");
+      CVS = std::move(TakeStrings);
+    } else
+      CVS = SS.Subsection->toCodeViewSubsection(Allocator, StringsRef, CS);
     assert(CVS != nullptr);
     Result.push_back(std::move(CVS));
   }
@@ -759,23 +810,23 @@ struct SubsectionConversionVisitor : public DebugSubsectionVisitor {
 
   Error visitUnknown(DebugUnknownSubsectionRef &Unknown) override;
   Error visitLines(DebugLinesSubsectionRef &Lines,
-                   const StringsAndChecksumsRef &State) override;
+                   const DebugSubsectionState &State) override;
   Error visitFileChecksums(DebugChecksumsSubsectionRef &Checksums,
-                           const StringsAndChecksumsRef &State) override;
+                           const DebugSubsectionState &State) override;
   Error visitInlineeLines(DebugInlineeLinesSubsectionRef &Inlinees,
-                          const StringsAndChecksumsRef &State) override;
+                          const DebugSubsectionState &State) override;
   Error visitCrossModuleExports(DebugCrossModuleExportsSubsectionRef &Checksums,
-                                const StringsAndChecksumsRef &State) override;
+                                const DebugSubsectionState &State) override;
   Error visitCrossModuleImports(DebugCrossModuleImportsSubsectionRef &Inlinees,
-                                const StringsAndChecksumsRef &State) override;
+                                const DebugSubsectionState &State) override;
   Error visitStringTable(DebugStringTableSubsectionRef &ST,
-                         const StringsAndChecksumsRef &State) override;
+                         const DebugSubsectionState &State) override;
   Error visitSymbols(DebugSymbolsSubsectionRef &Symbols,
-                     const StringsAndChecksumsRef &State) override;
+                     const DebugSubsectionState &State) override;
   Error visitFrameData(DebugFrameDataSubsectionRef &Symbols,
-                       const StringsAndChecksumsRef &State) override;
+                       const DebugSubsectionState &State) override;
   Error visitCOFFSymbolRVAs(DebugSymbolRVASubsectionRef &Symbols,
-                            const StringsAndChecksumsRef &State) override;
+                            const DebugSubsectionState &State) override;
 
   YAMLDebugSubsection Subsection;
 };
@@ -786,7 +837,7 @@ Error SubsectionConversionVisitor::visitUnknown(
 }
 
 Error SubsectionConversionVisitor::visitLines(
-    DebugLinesSubsectionRef &Lines, const StringsAndChecksumsRef &State) {
+    DebugLinesSubsectionRef &Lines, const DebugSubsectionState &State) {
   auto Result = YAMLLinesSubsection::fromCodeViewSubsection(
       State.strings(), State.checksums(), Lines);
   if (!Result)
@@ -796,8 +847,7 @@ Error SubsectionConversionVisitor::visitLines(
 }
 
 Error SubsectionConversionVisitor::visitFileChecksums(
-    DebugChecksumsSubsectionRef &Checksums,
-    const StringsAndChecksumsRef &State) {
+    DebugChecksumsSubsectionRef &Checksums, const DebugSubsectionState &State) {
   auto Result = YAMLChecksumsSubsection::fromCodeViewSubsection(State.strings(),
                                                                 Checksums);
   if (!Result)
@@ -808,7 +858,7 @@ Error SubsectionConversionVisitor::visitFileChecksums(
 
 Error SubsectionConversionVisitor::visitInlineeLines(
     DebugInlineeLinesSubsectionRef &Inlinees,
-    const StringsAndChecksumsRef &State) {
+    const DebugSubsectionState &State) {
   auto Result = YAMLInlineeLinesSubsection::fromCodeViewSubsection(
       State.strings(), State.checksums(), Inlinees);
   if (!Result)
@@ -819,7 +869,7 @@ Error SubsectionConversionVisitor::visitInlineeLines(
 
 Error SubsectionConversionVisitor::visitCrossModuleExports(
     DebugCrossModuleExportsSubsectionRef &Exports,
-    const StringsAndChecksumsRef &State) {
+    const DebugSubsectionState &State) {
   auto Result =
       YAMLCrossModuleExportsSubsection::fromCodeViewSubsection(Exports);
   if (!Result)
@@ -830,7 +880,7 @@ Error SubsectionConversionVisitor::visitCrossModuleExports(
 
 Error SubsectionConversionVisitor::visitCrossModuleImports(
     DebugCrossModuleImportsSubsectionRef &Imports,
-    const StringsAndChecksumsRef &State) {
+    const DebugSubsectionState &State) {
   auto Result = YAMLCrossModuleImportsSubsection::fromCodeViewSubsection(
       State.strings(), Imports);
   if (!Result)
@@ -840,8 +890,7 @@ Error SubsectionConversionVisitor::visitCrossModuleImports(
 }
 
 Error SubsectionConversionVisitor::visitStringTable(
-    DebugStringTableSubsectionRef &Strings,
-    const StringsAndChecksumsRef &State) {
+    DebugStringTableSubsectionRef &Strings, const DebugSubsectionState &State) {
   auto Result = YAMLStringTableSubsection::fromCodeViewSubsection(Strings);
   if (!Result)
     return Result.takeError();
@@ -850,7 +899,7 @@ Error SubsectionConversionVisitor::visitStringTable(
 }
 
 Error SubsectionConversionVisitor::visitSymbols(
-    DebugSymbolsSubsectionRef &Symbols, const StringsAndChecksumsRef &State) {
+    DebugSymbolsSubsectionRef &Symbols, const DebugSubsectionState &State) {
   auto Result = YAMLSymbolsSubsection::fromCodeViewSubsection(Symbols);
   if (!Result)
     return Result.takeError();
@@ -859,7 +908,7 @@ Error SubsectionConversionVisitor::visitSymbols(
 }
 
 Error SubsectionConversionVisitor::visitFrameData(
-    DebugFrameDataSubsectionRef &Frames, const StringsAndChecksumsRef &State) {
+    DebugFrameDataSubsectionRef &Frames, const DebugSubsectionState &State) {
   auto Result =
       YAMLFrameDataSubsection::fromCodeViewSubsection(State.strings(), Frames);
   if (!Result)
@@ -869,7 +918,7 @@ Error SubsectionConversionVisitor::visitFrameData(
 }
 
 Error SubsectionConversionVisitor::visitCOFFSymbolRVAs(
-    DebugSymbolRVASubsectionRef &RVAs, const StringsAndChecksumsRef &State) {
+    DebugSymbolRVASubsectionRef &RVAs, const DebugSubsectionState &State) {
   auto Result = YAMLCoffSymbolRVASubsection::fromCodeViewSubsection(RVAs);
   if (!Result)
     return Result.takeError();
@@ -878,71 +927,29 @@ Error SubsectionConversionVisitor::visitCOFFSymbolRVAs(
 }
 }
 
-Expected<YAMLDebugSubsection>
-YAMLDebugSubsection::fromCodeViewSubection(const StringsAndChecksumsRef &SC,
-                                           const DebugSubsectionRecord &SS) {
+Expected<YAMLDebugSubsection> YAMLDebugSubsection::fromCodeViewSubection(
+    const DebugStringTableSubsectionRef &Strings,
+    const DebugChecksumsSubsectionRef &Checksums,
+    const DebugSubsectionRecord &SS) {
+  DebugSubsectionState State(Strings, Checksums);
   SubsectionConversionVisitor V;
-  if (auto EC = visitDebugSubsection(SS, V, SC))
+  if (auto EC = visitDebugSubsection(SS, V, State))
     return std::move(EC);
 
   return V.Subsection;
 }
 
-std::vector<YAMLDebugSubsection>
-llvm::CodeViewYAML::fromDebugS(ArrayRef<uint8_t> Data,
-                               const StringsAndChecksumsRef &SC) {
-  BinaryStreamReader Reader(Data, support::little);
-  uint32_t Magic;
-
-  ExitOnError Err("Invalid .debug$S section!");
-  Err(Reader.readInteger(Magic));
-  assert(Magic == COFF::DEBUG_SECTION_MAGIC && "Invalid .debug$S section!");
-
-  DebugSubsectionArray Subsections;
-  Err(Reader.readArray(Subsections, Reader.bytesRemaining()));
-
-  std::vector<YAMLDebugSubsection> Result;
-
-  for (const auto &SS : Subsections) {
-    auto YamlSS = Err(YAMLDebugSubsection::fromCodeViewSubection(SC, SS));
-    Result.push_back(YamlSS);
-  }
-  return Result;
-}
-
-void llvm::CodeViewYAML::initializeStringsAndChecksums(
-    ArrayRef<YAMLDebugSubsection> Sections, codeview::StringsAndChecksums &SC) {
-  // String Table and Checksums subsections don't use the allocator.
-  BumpPtrAllocator Allocator;
-
-  // It's possible for checksums and strings to even appear in different debug$S
-  // sections, so we have to make this a stateful function that can build up
-  // the strings and checksums field over multiple iterations.
-
-  // File Checksums require the string table, but may become before it, so we
-  // have to scan for strings first, then scan for checksums again from the
-  // beginning.
-  if (!SC.hasStrings()) {
-    for (const auto &SS : Sections) {
-      if (SS.Subsection->Kind != DebugSubsectionKind::StringTable)
-        continue;
-
-      auto Result = SS.Subsection->toCodeViewSubsection(Allocator, SC);
-      SC.setStrings(
-          std::static_pointer_cast<DebugStringTableSubsection>(Result));
-      break;
-    }
-  }
-
-  if (SC.hasStrings() && !SC.hasChecksums()) {
-    for (const auto &SS : Sections) {
-      if (SS.Subsection->Kind != DebugSubsectionKind::FileChecksums)
-        continue;
+std::unique_ptr<DebugStringTableSubsection>
+llvm::CodeViewYAML::findStringTable(ArrayRef<YAMLDebugSubsection> Sections) {
+  for (const auto &SS : Sections) {
+    if (SS.Subsection->Kind != DebugSubsectionKind::StringTable)
+      continue;
 
-      auto Result = SS.Subsection->toCodeViewSubsection(Allocator, SC);
-      SC.setChecksums(
-          std::static_pointer_cast<DebugChecksumsSubsection>(Result));
-      break;
-    }
+    // String Table doesn't use the allocator.
+    BumpPtrAllocator Allocator;
+    auto Result =
+        SS.Subsection->toCodeViewSubsection(Allocator, nullptr, nullptr);
+    return llvm::cast<DebugStringTableSubsection>(std::move(Result));
   }
+  return nullptr;
 }
diff --git a/lib/ObjectYAML/CodeViewYAMLTypes.cpp b/lib/ObjectYAML/CodeViewYAMLTypes.cpp
index a03b9cd50fa..1302b0713d0 100644
--- a/lib/ObjectYAML/CodeViewYAMLTypes.cpp
+++ b/lib/ObjectYAML/CodeViewYAMLTypes.cpp
@@ -714,43 +714,3 @@ void MappingTraits<MemberRecord>::mapping(IO &IO, MemberRecord &Obj) {
   default: { llvm_unreachable("Unknown member kind!"); }
   }
 }
-
-std::vector<LeafRecord>
-llvm::CodeViewYAML::fromDebugT(ArrayRef<uint8_t> DebugT) {
-  ExitOnError Err("Invalid .debug$T section!");
-  BinaryStreamReader Reader(DebugT, support::little);
-  CVTypeArray Types;
-  uint32_t Magic;
-
-  Err(Reader.readInteger(Magic));
-  assert(Magic == COFF::DEBUG_SECTION_MAGIC && "Invalid .debug$T section!");
-
-  std::vector<LeafRecord> Result;
-  Err(Reader.readArray(Types, Reader.bytesRemaining()));
-  for (const auto &T : Types) {
-    auto CVT = Err(LeafRecord::fromCodeViewRecord(T));
-    Result.push_back(CVT);
-  }
-  return Result;
-}
-
-ArrayRef<uint8_t> llvm::CodeViewYAML::toDebugT(ArrayRef<LeafRecord> Leafs,
-                                               BumpPtrAllocator &Alloc) {
-  TypeTableBuilder TTB(Alloc, false);
-  uint32_t Size = sizeof(uint32_t);
-  for (const auto &Leaf : Leafs) {
-    CVType T = Leaf.toCodeViewRecord(TTB);
-    Size += T.length();
-    assert(T.length() % 4 == 0 && "Improper type record alignment!");
-  }
-  uint8_t *ResultBuffer = Alloc.Allocate<uint8_t>(Size);
-  MutableArrayRef<uint8_t> Output(ResultBuffer, Size);
-  BinaryStreamWriter Writer(Output, support::little);
-  ExitOnError Err("Error writing type record to .debug$T section");
-  Err(Writer.writeInteger<uint32_t>(COFF::DEBUG_SECTION_MAGIC));
-  for (const auto &R : TTB.records()) {
-    Err(Writer.writeBytes(R));
-  }
-  assert(Writer.bytesRemaining() == 0 && "Didn't write all type record bytes!");
-  return Output;
-}