[pdb] Add the ability to resolve TypeServer PDBs.

Some PDBs or object files can contain references to other PDBs
where the real type information lives.  When this happens,
all type indices in the original PDB are meaningless because
their records are not there.

With this patch we add the ability to pull type info from those
secondary PDBs.

Differential Revision: https://reviews.llvm.org/D29973

llvm-svn: 295382

lld/COFF/PDB.cpp

@@ -29,12 +29,14 @@
 #include "llvm/DebugInfo/PDB/Native/InfoStreamBuilder.h"
 #include "llvm/DebugInfo/PDB/Native/PDBFile.h"
 #include "llvm/DebugInfo/PDB/Native/PDBFileBuilder.h"
+#include "llvm/DebugInfo/PDB/Native/PDBTypeServerHandler.h"
 #include "llvm/DebugInfo/PDB/Native/StringTableBuilder.h"
 #include "llvm/DebugInfo/PDB/Native/TpiStream.h"
 #include "llvm/DebugInfo/PDB/Native/TpiStreamBuilder.h"
 #include "llvm/Object/COFF.h"
 #include "llvm/Support/Endian.h"
 #include "llvm/Support/FileOutputBuffer.h"
+#include "llvm/Support/Path.h"
 #include "llvm/Support/ScopedPrinter.h"
 #include <memory>
 
@@ -94,9 +96,15 @@ static std::vector<uint8_t> mergeDebugT(SymbolTable *Symtab) {
     msf::ByteStream Stream(Data);
     codeview::CVTypeArray Types;
     msf::StreamReader Reader(Stream);
+    // Follow type servers.  If the same type server is encountered more than
+    // once for this instance of `PDBTypeServerHandler` (for example if many
+    // object files reference the same TypeServer), the types from the
+    // TypeServer will only be visited once.
+    pdb::PDBTypeServerHandler Handler;
+    Handler.addSearchPath(llvm::sys::path::parent_path(File->getName()));
     if (auto EC = Reader.readArray(Types, Reader.getLength()))
       fatal(EC, "Reader::readArray failed");
-    if (auto Err = codeview::mergeTypeStreams(Builder, Types))
+    if (auto Err = codeview::mergeTypeStreams(Builder, &Handler, Types))
       fatal(Err, "codeview::mergeTypeStreams failed");
   }
 
@@ -116,6 +124,8 @@ static void dumpDebugT(ScopedPrinter &W, ObjectFile *File) {
 
   TypeDatabase TDB;
   TypeDumpVisitor TDV(TDB, &W, false);
+  // Use a default implementation that does not follow type servers and instead
+  // just dumps the contents of the TypeServer2 record.
   CVTypeDumper TypeDumper(TDB);
   if (auto EC = TypeDumper.dump(Data, TDV))
     fatal(EC, "CVTypeDumper::dump failed");

llvm/include/llvm/DebugInfo/CodeView/CVTypeDumper.h

@@ -22,10 +22,14 @@ namespace llvm {
 
 namespace codeview {
 
+class TypeServerHandler;
+
 /// Dumper for CodeView type streams found in COFF object files and PDB files.
 class CVTypeDumper {
 public:
-  explicit CVTypeDumper(TypeDatabase &TypeDB) : TypeDB(TypeDB) {}
+  explicit CVTypeDumper(TypeDatabase &TypeDB,
+                        TypeServerHandler *Handler = nullptr)
+      : TypeDB(TypeDB), Handler(Handler) {}
 
   /// Dumps one type record.  Returns false if there was a type parsing error,
   /// and true otherwise.  This should be called in order, since the dumper
@@ -48,6 +52,7 @@ public:
 
 private:
   TypeDatabase &TypeDB;
+  TypeServerHandler *Handler;
 };
 
 } // end namespace codeview

llvm/include/llvm/DebugInfo/CodeView/CVTypeVisitor.h

@@ -10,9 +10,10 @@
 #ifndef LLVM_DEBUGINFO_CODEVIEW_CVTYPEVISITOR_H
 #define LLVM_DEBUGINFO_CODEVIEW_CVTYPEVISITOR_H
 
-#include "llvm/ADT/SmallVector.h"
+#include "llvm/ADT/TinyPtrVector.h"
 #include "llvm/DebugInfo/CodeView/CVRecord.h"
 #include "llvm/DebugInfo/CodeView/TypeRecord.h"
+#include "llvm/DebugInfo/CodeView/TypeServerHandler.h"
 #include "llvm/DebugInfo/CodeView/TypeVisitorCallbacks.h"
 #include "llvm/Support/Error.h"
 
@@ -23,11 +24,14 @@ class CVTypeVisitor {
 public:
   explicit CVTypeVisitor(TypeVisitorCallbacks &Callbacks);
 
+  void addTypeServerHandler(TypeServerHandler &Handler);
+
   Error visitTypeRecord(CVType &Record);
   Error visitMemberRecord(CVMemberRecord &Record);
 
   /// Visits the type records in Data. Sets the error flag on parse failures.
   Error visitTypeStream(const CVTypeArray &Types);
+  Error visitTypeStream(CVTypeRange Types);
 
   Error visitFieldListMemberStream(ArrayRef<uint8_t> FieldList);
   Error visitFieldListMemberStream(msf::StreamReader Reader);
@@ -35,6 +39,8 @@ public:
 private:
   /// The interface to the class that gets notified of each visitation.
   TypeVisitorCallbacks &Callbacks;
+
+  TinyPtrVector<TypeServerHandler *> Handlers;
 };
 
 } // end namespace codeview

llvm/include/llvm/DebugInfo/CodeView/CodeViewError.h

@@ -21,6 +21,7 @@ enum class cv_error_code {
   insufficient_buffer,
   operation_unsupported,
   corrupt_record,
+  no_records,
   unknown_member_record,
 };
 

llvm/include/llvm/DebugInfo/CodeView/TypeRecord.h

@@ -43,6 +43,7 @@ struct CVMemberRecord {
   ArrayRef<uint8_t> Data;
 };
 typedef msf::VarStreamArray<CVType> CVTypeArray;
+typedef iterator_range<CVTypeArray::Iterator> CVTypeRange;
 
 /// Equvalent to CV_fldattr_t in cvinfo.h.
 struct MemberAttributes {

llvm/include/llvm/DebugInfo/CodeView/TypeServerHandler.h

@@ -0,0 +1,36 @@
+//===- TypeServerHandler.h --------------------------------------*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_DEBUGINFO_CODEVIEW_TYPESERVERHANDLER_H
+#define LLVM_DEBUGINFO_CODEVIEW_TYPESERVERHANDLER_H
+
+#include "llvm/DebugInfo/CodeView/TypeRecord.h"
+#include "llvm/Support/Error.h"
+
+namespace llvm {
+namespace codeview {
+class TypeVisitorCallbacks;
+
+class TypeServerHandler {
+public:
+  virtual ~TypeServerHandler() {}
+
+  /// Handle a TypeServer record.  If the implementation returns true
+  /// the record will not be processed by the top-level visitor.  If
+  /// it returns false, it will be processed.  If it returns an Error,
+  /// then the top-level visitor will fail.
+  virtual Expected<bool> handle(TypeServer2Record &TS,
+                                TypeVisitorCallbacks &Callbacks) {
+    return false;
+  }
+};
+}
+}
+
+#endif

llvm/include/llvm/DebugInfo/CodeView/TypeStreamMerger.h

@@ -18,8 +18,11 @@
 namespace llvm {
 namespace codeview {
 
+class TypeServerHandler;
+
 /// Merges one type stream into another. Returns true on success.
-Error mergeTypeStreams(TypeTableBuilder &DestStream, const CVTypeArray &Types);
+Error mergeTypeStreams(TypeTableBuilder &DestStream, TypeServerHandler *Handler,
+                       const CVTypeArray &Types);
 
 } // end namespace codeview
 } // end namespace llvm

llvm/include/llvm/DebugInfo/PDB/Native/PDBFile.h

@@ -42,10 +42,13 @@ class PDBFile : public msf::IMSFFile {
   friend PDBFileBuilder;
 
 public:
-  PDBFile(std::unique_ptr<msf::ReadableStream> PdbFileBuffer,
+  PDBFile(StringRef Path, std::unique_ptr<msf::ReadableStream> PdbFileBuffer,
           BumpPtrAllocator &Allocator);
   ~PDBFile() override;
 
+  StringRef getFileDirectory() const;
+  StringRef getFilePath() const;
+
   uint32_t getFreeBlockMapBlock() const;
   uint32_t getUnknown1() const;
 
@@ -110,6 +113,7 @@ private:
                             const msf::ReadableStream &MsfData,
                             uint32_t StreamIndex) const;
 
+  std::string FilePath;
   BumpPtrAllocator &Allocator;
 
   std::unique_ptr<msf::ReadableStream> Buffer;

llvm/include/llvm/DebugInfo/PDB/Native/PDBTypeServerHandler.h

@@ -0,0 +1,48 @@
+//===- PDBTypeServerHandler.h -----------------------------------*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_DEBUGINFO_PDB_PDBTYPESERVERHANDLER_H
+#define LLVM_DEBUGINFO_PDB_PDBTYPESERVERHANDLER_H
+
+#include "llvm/ADT/SmallString.h"
+#include "llvm/ADT/SmallVector.h"
+#include "llvm/ADT/StringMap.h"
+#include "llvm/DebugInfo/CodeView/CVTypeVisitor.h"
+#include "llvm/DebugInfo/CodeView/TypeRecord.h"
+#include "llvm/DebugInfo/CodeView/TypeServerHandler.h"
+#include "llvm/DebugInfo/PDB/Native/NativeSession.h"
+#include "llvm/DebugInfo/PDB/PDBTypes.h"
+
+#include <memory>
+#include <string>
+
+namespace llvm {
+namespace pdb {
+class NativeSession;
+
+class PDBTypeServerHandler : public codeview::TypeServerHandler {
+public:
+  PDBTypeServerHandler(bool RevisitAlways = false);
+
+  void addSearchPath(StringRef Path);
+  Expected<bool> handle(codeview::TypeServer2Record &TS,
+                        codeview::TypeVisitorCallbacks &Callbacks) override;
+
+private:
+  Expected<bool> handleInternal(PDBFile &File,
+                                codeview::TypeVisitorCallbacks &Callbacks);
+
+  bool RevisitAlways;
+  std::unique_ptr<NativeSession> Session;
+  SmallVector<SmallString<64>, 4> SearchPaths;
+};
+}
+}
+
+#endif

llvm/include/llvm/DebugInfo/PDB/Native/TpiStream.h

@@ -50,7 +50,7 @@ public:
   msf::FixedStreamArray<TypeIndexOffset> getTypeIndexOffsets() const;
   HashTable &getHashAdjusters();
 
-  iterator_range<codeview::CVTypeArray::Iterator> types(bool *HadError) const;
+  codeview::CVTypeRange types(bool *HadError) const;
 
   Error commit();
 

llvm/lib/DebugInfo/CodeView/CVTypeDumper.cpp

@@ -28,6 +28,8 @@ Error CVTypeDumper::dump(const CVType &Record, TypeVisitorCallbacks &Dumper) {
   Pipeline.addCallbackToPipeline(Dumper);
 
   CVTypeVisitor Visitor(Pipeline);
+  if (Handler)
+    Visitor.addTypeServerHandler(*Handler);
 
   CVType RecordCopy = Record;
   if (auto EC = Visitor.visitTypeRecord(RecordCopy))
@@ -45,6 +47,8 @@ Error CVTypeDumper::dump(const CVTypeArray &Types,
   Pipeline.addCallbackToPipeline(Dumper);
 
   CVTypeVisitor Visitor(Pipeline);
+  if (Handler)
+    Visitor.addTypeServerHandler(*Handler);
 
   if (auto EC = Visitor.visitTypeStream(Types))
     return EC;

llvm/lib/DebugInfo/CodeView/CVTypeVisitor.cpp

@@ -10,9 +10,14 @@
 #include "llvm/DebugInfo/CodeView/CVTypeVisitor.h"
 
 #include "llvm/DebugInfo/CodeView/CodeViewError.h"
+#include "llvm/DebugInfo/CodeView/TypeDatabase.h"
+#include "llvm/DebugInfo/CodeView/TypeDatabaseVisitor.h"
 #include "llvm/DebugInfo/CodeView/TypeDeserializer.h"
+#include "llvm/DebugInfo/CodeView/TypeRecordMapping.h"
+#include "llvm/DebugInfo/CodeView/TypeServerHandler.h"
 #include "llvm/DebugInfo/CodeView/TypeVisitorCallbackPipeline.h"
 #include "llvm/DebugInfo/MSF/ByteStream.h"
+#include "llvm/DebugInfo/MSF/StreamReader.h"
 
 using namespace llvm;
 using namespace llvm::codeview;
@@ -21,7 +26,8 @@ CVTypeVisitor::CVTypeVisitor(TypeVisitorCallbacks &Callbacks)
     : Callbacks(Callbacks) {}
 
 template <typename T>
-static Error visitKnownRecord(CVType &Record, TypeVisitorCallbacks &Callbacks) {
+static Error visitKnownRecord(CVTypeVisitor &Visitor, CVType &Record,
+                              TypeVisitorCallbacks &Callbacks) {
   TypeRecordKind RK = static_cast<TypeRecordKind>(Record.Type);
   T KnownRecord(RK);
   if (auto EC = Callbacks.visitKnownRecord(Record, KnownRecord))
@@ -39,7 +45,58 @@ static Error visitKnownMember(CVMemberRecord &Record,
   return Error::success();
 }
 
+static Expected<TypeServer2Record> deserializeTypeServerRecord(CVType &Record) {
+  class StealTypeServerVisitor : public TypeVisitorCallbacks {
+  public:
+    explicit StealTypeServerVisitor(TypeServer2Record &TR) : TR(TR) {}
+
+    Error visitKnownRecord(CVType &CVR, TypeServer2Record &Record) override {
+      TR = Record;
+      return Error::success();
+    }
+
+  private:
+    TypeServer2Record &TR;
+  };
+
+  TypeServer2Record R(TypeRecordKind::TypeServer2);
+  TypeDeserializer Deserializer;
+  StealTypeServerVisitor Thief(R);
+  TypeVisitorCallbackPipeline Pipeline;
+  Pipeline.addCallbackToPipeline(Deserializer);
+  Pipeline.addCallbackToPipeline(Thief);
+  CVTypeVisitor Visitor(Pipeline);
+  if (auto EC = Visitor.visitTypeRecord(Record))
+    return std::move(EC);
+
+  return R;
+}
+
+void CVTypeVisitor::addTypeServerHandler(TypeServerHandler &Handler) {
+  Handlers.push_back(&Handler);
+}
+
 Error CVTypeVisitor::visitTypeRecord(CVType &Record) {
+  if (Record.Type == TypeLeafKind::LF_TYPESERVER2 && !Handlers.empty()) {
+    auto TS = deserializeTypeServerRecord(Record);
+    if (!TS)
+      return TS.takeError();
+
+    for (auto Handler : Handlers) {
+      auto ExpectedResult = Handler->handle(*TS, Callbacks);
+      // If there was an error, return the error.
+      if (!ExpectedResult)
+        return ExpectedResult.takeError();
+
+      // If the handler processed the record, return success.
+      if (*ExpectedResult)
+        return Error::success();
+
+      // Otherwise keep searching for a handler, eventually falling out and
+      // using the default record handler.
+    }
+  }
+
   if (auto EC = Callbacks.visitTypeBegin(Record))
     return EC;
 
@@ -50,7 +107,7 @@ Error CVTypeVisitor::visitTypeRecord(CVType &Record) {
     break;
 #define TYPE_RECORD(EnumName, EnumVal, Name)                                   \
   case EnumName: {                                                             \
-    if (auto EC = visitKnownRecord<Name##Record>(Record, Callbacks))           \
+    if (auto EC = visitKnownRecord<Name##Record>(*this, Record, Callbacks))    \
       return EC;                                                               \
     break;                                                                     \
   }
@@ -109,6 +166,14 @@ Error CVTypeVisitor::visitTypeStream(const CVTypeArray &Types) {
   return Error::success();
 }
 
+Error CVTypeVisitor::visitTypeStream(CVTypeRange Types) {
+  for (auto I : Types) {
+    if (auto EC = visitTypeRecord(I))
+      return EC;
+  }
+  return Error::success();
+}
+
 Error CVTypeVisitor::visitFieldListMemberStream(msf::StreamReader Reader) {
   FieldListDeserializer Deserializer(Reader);
   TypeVisitorCallbackPipeline Pipeline;

llvm/lib/DebugInfo/CodeView/CodeViewError.cpp

@@ -31,6 +31,8 @@ public:
              "bytes.";
     case cv_error_code::corrupt_record:
       return "The CodeView record is corrupted.";
+    case cv_error_code::no_records:
+      return "There are no records";
     case cv_error_code::operation_unsupported:
       return "The requested operation is not supported.";
     case cv_error_code::unknown_member_record:

llvm/lib/DebugInfo/CodeView/TypeStreamMerger.cpp

@@ -54,8 +54,9 @@ namespace {
 ///   existing destination type index.
 class TypeStreamMerger : public TypeVisitorCallbacks {
 public:
-  TypeStreamMerger(TypeTableBuilder &DestStream)
-      : DestStream(DestStream), FieldListBuilder(DestStream) {}
+  TypeStreamMerger(TypeTableBuilder &DestStream, TypeServerHandler *Handler)
+      : DestStream(DestStream), FieldListBuilder(DestStream), Handler(Handler) {
+  }
 
 /// TypeVisitorCallbacks overrides.
 #define TYPE_RECORD(EnumName, EnumVal, Name)                                   \
@@ -109,6 +110,7 @@ private:
 
   TypeTableBuilder &DestStream;
   FieldListRecordBuilder FieldListBuilder;
+  TypeServerHandler *Handler;
 
   bool IsInFieldList{false};
   size_t BeginIndexMapSize = 0;
@@ -175,6 +177,8 @@ Error TypeStreamMerger::mergeStream(const CVTypeArray &Types) {
   Pipeline.addCallbackToPipeline(*this);
 
   CVTypeVisitor Visitor(Pipeline);
+  if (Handler)
+    Visitor.addTypeServerHandler(*Handler);
 
   if (auto EC = Visitor.visitTypeStream(Types))
     return EC;
@@ -186,6 +190,7 @@ Error TypeStreamMerger::mergeStream(const CVTypeArray &Types) {
 }
 
 Error llvm::codeview::mergeTypeStreams(TypeTableBuilder &DestStream,
+                                       TypeServerHandler *Handler,
                                        const CVTypeArray &Types) {
-  return TypeStreamMerger(DestStream).mergeStream(Types);
+  return TypeStreamMerger(DestStream, Handler).mergeStream(Types);
 }

llvm/lib/DebugInfo/PDB/CMakeLists.txt

@@ -44,6 +44,7 @@ add_pdb_impl_folder(Native
   Native/NativeSession.cpp
   Native/PDBFile.cpp
   Native/PDBFileBuilder.cpp
+  Native/PDBTypeServerHandler.cpp
   Native/PublicsStream.cpp
   Native/RawError.cpp
   Native/StringTable.cpp

llvm/lib/DebugInfo/PDB/Native/NativeSession.cpp

@@ -47,7 +47,7 @@ Error NativeSession::createFromPdb(StringRef Path,
   auto Stream = llvm::make_unique<MemoryBufferByteStream>(std::move(Buffer));
 
   auto Allocator = llvm::make_unique<BumpPtrAllocator>();
-  auto File = llvm::make_unique<PDBFile>(std::move(Stream), *Allocator);
+  auto File = llvm::make_unique<PDBFile>(Path, std::move(Stream), *Allocator);
   if (auto EC = File->parseFileHeaders())
     return EC;
   if (auto EC = File->parseStreamData())

llvm/lib/DebugInfo/PDB/Native/PDBFile.cpp

@@ -25,6 +25,7 @@
 #include "llvm/DebugInfo/PDB/Native/TpiStream.h"
 #include "llvm/Support/Endian.h"
 #include "llvm/Support/Error.h"
+#include "llvm/Support/Path.h"
 #include <algorithm>
 #include <cassert>
 #include <cstdint>
@@ -38,12 +39,18 @@ namespace {
 typedef FixedStreamArray<support::ulittle32_t> ulittle_array;
 } // end anonymous namespace
 
-PDBFile::PDBFile(std::unique_ptr<ReadableStream> PdbFileBuffer,
+PDBFile::PDBFile(StringRef Path, std::unique_ptr<ReadableStream> PdbFileBuffer,
                  BumpPtrAllocator &Allocator)
-    : Allocator(Allocator), Buffer(std::move(PdbFileBuffer)) {}
+    : FilePath(Path), Allocator(Allocator), Buffer(std::move(PdbFileBuffer)) {}
 
 PDBFile::~PDBFile() = default;
 
+StringRef PDBFile::getFilePath() const { return FilePath; }
+
+StringRef PDBFile::getFileDirectory() const {
+  return sys::path::parent_path(FilePath);
+}
+
 uint32_t PDBFile::getBlockSize() const { return ContainerLayout.SB->BlockSize; }
 
 uint32_t PDBFile::getFreeBlockMapBlock() const {

llvm/lib/DebugInfo/PDB/Native/PDBTypeServerHandler.cpp

@@ -0,0 +1,119 @@
+//===- PDBTypeServerHandler.cpp ---------------------------------*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+// Handles CodeView LF_TYPESERVER2 records by attempting to locate a matching
+// PDB file, then loading the PDB file and visiting all types from the
+// referenced PDB using the original supplied visitor.
+//
+// The net effect of this is that when visiting a PDB containing a TypeServer
+// record, the TypeServer record is "replaced" with all of the records in
+// the referenced PDB file.  If a single instance of PDBTypeServerHandler
+// encounters the same TypeServer multiple times (for example reusing one
+// PDBTypeServerHandler across multiple visitations of distinct object files or
+// PDB files), PDBTypeServerHandler will optionally revisit all the records
+// again, or simply consume the record and do nothing.
+//===----------------------------------------------------------------------===//
+
+#include "llvm/DebugInfo/PDB/Native/PDBTypeServerHandler.h"
+
+#include "llvm/DebugInfo/CodeView/CodeViewError.h"
+#include "llvm/DebugInfo/PDB/GenericError.h"
+#include "llvm/DebugInfo/PDB/Native/InfoStream.h"
+#include "llvm/DebugInfo/PDB/Native/NativeSession.h"
+#include "llvm/DebugInfo/PDB/Native/PDBFile.h"
+#include "llvm/DebugInfo/PDB/Native/TpiStream.h"
+#include "llvm/DebugInfo/PDB/PDB.h"
+#include "llvm/Support/FileSystem.h"
+#include "llvm/Support/Path.h"
+
+using namespace llvm;
+using namespace llvm::codeview;
+using namespace llvm::pdb;
+
+static void ignoreErrors(Error EC) {
+  llvm::handleAllErrors(std::move(EC), [&](ErrorInfoBase &EIB) {});
+}
+
+PDBTypeServerHandler::PDBTypeServerHandler(bool RevisitAlways)
+    : RevisitAlways(RevisitAlways) {}
+
+void PDBTypeServerHandler::addSearchPath(StringRef Path) {
+  if (Path.empty() || !sys::fs::is_directory(Path))
+    return;
+
+  SearchPaths.push_back(Path);
+}
+
+Expected<bool>
+PDBTypeServerHandler::handleInternal(PDBFile &File,
+                                     TypeVisitorCallbacks &Callbacks) {
+  auto ExpectedTpi = File.getPDBTpiStream();
+  if (!ExpectedTpi)
+    return ExpectedTpi.takeError();
+  CVTypeVisitor Visitor(Callbacks);
+
+  if (auto EC = Visitor.visitTypeStream(ExpectedTpi->types(nullptr)))
+    return std::move(EC);
+
+  return true;
+}
+
+Expected<bool> PDBTypeServerHandler::handle(TypeServer2Record &TS,
+                                            TypeVisitorCallbacks &Callbacks) {
+  if (Session) {
+    // If we've already handled this TypeServer and we only want to handle each
+    // TypeServer once, consume the record without doing anything.
+    if (!RevisitAlways)
+      return true;
+
+    return handleInternal(Session->getPDBFile(), Callbacks);
+  }
+
+  StringRef File = sys::path::filename(TS.Name);
+  if (File.empty())
+    return make_error<CodeViewError>(
+        cv_error_code::corrupt_record,
+        "TypeServer2Record does not contain filename!");
+
+  for (auto Path : SearchPaths) {
+    sys::path::append(Path, File);
+    if (!sys::fs::exists(Path))
+      continue;
+
+    std::unique_ptr<IPDBSession> ThisSession;
+    if (auto EC = loadDataForPDB(PDB_ReaderType::Native, Path, ThisSession)) {
+      // It is not an error if this PDB fails to load, it just means that it
+      // doesn't match and we should continue searching.
+      ignoreErrors(std::move(EC));
+      continue;
+    }
+
+    std::unique_ptr<NativeSession> NS(
+        static_cast<NativeSession *>(ThisSession.release()));
+    PDBFile &File = NS->getPDBFile();
+    auto ExpectedInfo = File.getPDBInfoStream();
+    // All PDB Files should have an Info stream.
+    if (!ExpectedInfo)
+      return ExpectedInfo.takeError();
+
+    // Just because a file with a matching name was found and it was an actual
+    // PDB file doesn't mean it matches.  For it to match the InfoStream's GUID
+    // must match the GUID specified in the TypeServer2 record.
+    ArrayRef<uint8_t> GuidBytes(ExpectedInfo->getGuid().Guid);
+    StringRef GuidStr(reinterpret_cast<const char *>(GuidBytes.begin()),
+                      GuidBytes.size());
+    if (GuidStr != TS.Guid)
+      continue;
+
+    Session = std::move(NS);
+    return handleInternal(File, Callbacks);
+  }
+
+  // We couldn't find a matching PDB, so let it be handled by someone else.
+  return false;
+}

llvm/lib/DebugInfo/PDB/Native/TpiStream.cpp

@@ -16,6 +16,7 @@
 #include "llvm/DebugInfo/MSF/MappedBlockStream.h"
 #include "llvm/DebugInfo/MSF/StreamReader.h"
 #include "llvm/DebugInfo/PDB/Native/PDBFile.h"
+#include "llvm/DebugInfo/PDB/Native/PDBTypeServerHandler.h"
 #include "llvm/DebugInfo/PDB/Native/RawConstants.h"
 #include "llvm/DebugInfo/PDB/Native/RawError.h"
 #include "llvm/DebugInfo/PDB/Native/RawTypes.h"
@@ -164,7 +165,7 @@ FixedStreamArray<TypeIndexOffset> TpiStream::getTypeIndexOffsets() const {
 
 HashTable &TpiStream::getHashAdjusters() { return HashAdjusters; }
 
-iterator_range<CVTypeArray::Iterator> TpiStream::types(bool *HadError) const {
+CVTypeRange TpiStream::types(bool *HadError) const {
   return make_range(TypeRecords.begin(HadError), TypeRecords.end());
 }
 

llvm/tools/llvm-readobj/CMakeLists.txt

@@ -4,6 +4,7 @@ set(LLVM_LINK_COMPONENTS
   Support
   DebugInfoCodeView
   DebugInfoMSF
+  DebugInfoPDB
   )
 
 add_llvm_tool(llvm-readobj

llvm/tools/llvm-readobj/COFFDumper.cpp

@@ -43,6 +43,7 @@
 #include "llvm/Support/Compiler.h"
 #include "llvm/Support/DataExtractor.h"
 #include "llvm/Support/Format.h"
+#include "llvm/Support/Path.h"
 #include "llvm/Support/ScopedPrinter.h"
 #include "llvm/Support/SourceMgr.h"
 #include "llvm/Support/Win64EH.h"
@@ -1086,7 +1087,7 @@ void COFFDumper::mergeCodeViewTypes(TypeTableBuilder &CVTypes) {
         error(object_error::parse_failed);
       }
 
-      if (auto EC = mergeTypeStreams(CVTypes, Types)) {
+      if (auto EC = mergeTypeStreams(CVTypes, nullptr, Types)) {
         consumeError(std::move(EC));
         return error(object_error::parse_failed);
       }

llvm/tools/llvm-readobj/LLVMBuild.txt

@@ -19,4 +19,4 @@
 type = Tool
 name = llvm-readobj
 parent = Tools
-required_libraries = all-targets BitReader Object DebugInfoCodeView DebugInfoMSF
+required_libraries = all-targets BitReader Object DebugInfoCodeView DebugInfoPDB DebugInfoMSF

llvm/unittests/DebugInfo/PDB/CMakeLists.txt

@@ -10,6 +10,7 @@ set(DebugInfoPDBSources
   StringTableBuilderTest.cpp
   MSFBuilderTest.cpp
   PDBApiTest.cpp
+  TypeServerHandlerTest.cpp
   )
 
 add_llvm_unittest(DebugInfoPDBTests

llvm/unittests/DebugInfo/PDB/TypeServerHandlerTest.cpp

@@ -0,0 +1,175 @@
+//===- llvm/unittest/DebugInfo/PDB/TypeServerHandlerTest.cpp --------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#include "ErrorChecking.h"
+
+#include "llvm/DebugInfo/CodeView/CVTypeVisitor.h"
+#include "llvm/DebugInfo/CodeView/TypeRecord.h"
+#include "llvm/DebugInfo/CodeView/TypeRecordMapping.h"
+#include "llvm/DebugInfo/CodeView/TypeSerializer.h"
+#include "llvm/DebugInfo/CodeView/TypeServerHandler.h"
+#include "llvm/DebugInfo/CodeView/TypeTableBuilder.h"
+#include "llvm/DebugInfo/CodeView/TypeVisitorCallbackPipeline.h"
+#include "llvm/DebugInfo/CodeView/TypeVisitorCallbacks.h"
+#include "llvm/DebugInfo/PDB/Native/RawTypes.h"
+#include "llvm/Support/Allocator.h"
+#include "llvm/Support/Error.h"
+
+#include "gtest/gtest.h"
+
+using namespace llvm;
+using namespace llvm::codeview;
+using namespace llvm::pdb;
+
+namespace {
+
+constexpr uint8_t Guid[] = {0x2a, 0x2c, 0x1c, 0x2a, 0xcb, 0x9e, 0x48, 0x18,
+                            0x82, 0x82, 0x7a, 0x87, 0xc3, 0xfe, 0x16, 0xe8};
+StringRef GuidStr(reinterpret_cast<const char *>(Guid),
+                  llvm::array_lengthof(Guid));
+
+constexpr const char *Name = "Test Name";
+constexpr int Age = 1;
+
+class MockTypeServerHandler : public TypeServerHandler {
+public:
+  explicit MockTypeServerHandler(bool HandleAlways)
+      : HandleAlways(HandleAlways) {}
+
+  Expected<bool> handle(TypeServer2Record &TS,
+                        TypeVisitorCallbacks &Callbacks) override {
+    if (TS.Age != Age || TS.Guid != GuidStr || TS.Name != Name)
+      return make_error<CodeViewError>(cv_error_code::corrupt_record,
+                                       "Invalid TypeServer record!");
+
+    if (Handled && !HandleAlways)
+      return false;
+
+    Handled = true;
+    return true;
+  }
+
+  bool Handled = false;
+  bool HandleAlways;
+};
+
+class MockTypeVisitorCallbacks : public TypeVisitorCallbacks {
+public:
+  enum class State {
+    Ready,
+    VisitTypeBegin,
+    VisitKnownRecord,
+    VisitTypeEnd,
+  };
+  Error visitTypeBegin(CVType &CVT) override {
+    if (S != State::Ready)
+      return make_error<CodeViewError>(cv_error_code::unspecified,
+                                       "Invalid visitor state!");
+
+    S = State::VisitTypeBegin;
+    return Error::success();
+  }
+
+  Error visitKnownRecord(CVType &CVT, TypeServer2Record &TS) override {
+    if (S != State::VisitTypeBegin)
+      return make_error<CodeViewError>(cv_error_code::unspecified,
+                                       "Invalid visitor state!");
+
+    S = State::VisitKnownRecord;
+    return Error::success();
+  }
+
+  Error visitTypeEnd(CVType &CVT) override {
+    if (S != State::VisitKnownRecord)
+      return make_error<CodeViewError>(cv_error_code::unspecified,
+                                       "Invalid visitor state!");
+
+    S = State::VisitTypeEnd;
+    return Error::success();
+  }
+
+  State S = State::Ready;
+};
+
+class TypeServerHandlerTest : public testing::Test {
+public:
+  void SetUp() override {
+    TypeServer2Record R(TypeRecordKind::TypeServer2);
+    R.Age = Age;
+    R.Guid = GuidStr;
+    R.Name = Name;
+
+    TypeTableBuilder Builder(Allocator);
+    Builder.writeKnownType(R);
+    TypeServerRecord.RecordData = Builder.records().front();
+    TypeServerRecord.Type = TypeLeafKind::LF_TYPESERVER2;
+  }
+
+protected:
+  BumpPtrAllocator Allocator;
+  CVType TypeServerRecord;
+};
+
+// Test that when no type server handler is registered, it gets handled by the
+// normal
+// visitor callbacks.
+TEST_F(TypeServerHandlerTest, VisitRecordNoTypeServer) {
+  MockTypeVisitorCallbacks C2;
+  MockTypeVisitorCallbacks C1;
+  TypeVisitorCallbackPipeline Pipeline;
+
+  Pipeline.addCallbackToPipeline(C1);
+  Pipeline.addCallbackToPipeline(C2);
+  CVTypeVisitor Visitor(Pipeline);
+  EXPECT_NO_ERROR(Visitor.visitTypeRecord(TypeServerRecord));
+
+  EXPECT_EQ(MockTypeVisitorCallbacks::State::VisitTypeEnd, C1.S);
+  EXPECT_EQ(MockTypeVisitorCallbacks::State::VisitTypeEnd, C2.S);
+}
+
+// Test that when a TypeServerHandler is registered, it gets consumed by the
+// handler if and only if the handler returns true.
+TEST_F(TypeServerHandlerTest, VisitRecordWithTypeServerOnce) {
+  MockTypeServerHandler Handler(false);
+
+  MockTypeVisitorCallbacks C1;
+  CVTypeVisitor Visitor(C1);
+  Visitor.addTypeServerHandler(Handler);
+
+  // Our mock server returns true the first time.
+  EXPECT_NO_ERROR(Visitor.visitTypeRecord(TypeServerRecord));
+  EXPECT_TRUE(Handler.Handled);
+  EXPECT_EQ(MockTypeVisitorCallbacks::State::Ready, C1.S);
+
+  // And false the second time.
+  EXPECT_NO_ERROR(Visitor.visitTypeRecord(TypeServerRecord));
+  EXPECT_TRUE(Handler.Handled);
+  EXPECT_EQ(MockTypeVisitorCallbacks::State::VisitTypeEnd, C1.S);
+}
+
+// Test that when a type server handler is registered, if the handler keeps
+// returning true, it will keep getting consumed by the handler and not go
+// to the default processor.
+TEST_F(TypeServerHandlerTest, VisitRecordWithTypeServerAlways) {
+  MockTypeServerHandler Handler(true);
+
+  MockTypeVisitorCallbacks C1;
+  CVTypeVisitor Visitor(C1);
+  Visitor.addTypeServerHandler(Handler);
+
+  EXPECT_NO_ERROR(Visitor.visitTypeRecord(TypeServerRecord));
+  EXPECT_TRUE(Handler.Handled);
+  EXPECT_EQ(MockTypeVisitorCallbacks::State::Ready, C1.S);
+
+  EXPECT_NO_ERROR(Visitor.visitTypeRecord(TypeServerRecord));
+  EXPECT_TRUE(Handler.Handled);
+  EXPECT_EQ(MockTypeVisitorCallbacks::State::Ready, C1.S);
+}
+
+} // end anonymous namespace