Index: include/llvm/DebugInfo/PDB/PDBExtras.h
===================================================================
--- include/llvm/DebugInfo/PDB/PDBExtras.h
+++ include/llvm/DebugInfo/PDB/PDBExtras.h
@@ -29,6 +29,7 @@
 raw_ostream &operator<<(raw_ostream &OS, const PDB_MemberAccess &Access);
 raw_ostream &operator<<(raw_ostream &OS, const PDB_UdtType &Type);
 raw_ostream &operator<<(raw_ostream &OS, const PDB_UniqueId &Id);
+raw_ostream &operator<<(raw_ostream &OS, const PDB_Machine &Machine);
 
 raw_ostream &operator<<(raw_ostream &OS, const Variant &Value);
 raw_ostream &operator<<(raw_ostream &OS, const VersionInfo &Version);
Index: include/llvm/DebugInfo/PDB/Raw/PDBDbiStream.h
===================================================================
--- /dev/null
+++ include/llvm/DebugInfo/PDB/Raw/PDBDbiStream.h
@@ -0,0 +1,52 @@
+//===- PDBDbiStream.h - PDB Dbi Stream (Stream 3) Access --------*- 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_RAW_PDBDBISTREAM_H
+#define LLVM_DEBUGINFO_PDB_RAW_PDBDBISTREAM_H
+
+#include "llvm/DebugInfo/PDB/PDBTypes.h"
+#include "llvm/DebugInfo/PDB/Raw/PDBRawConstants.h"
+#include "llvm/DebugInfo/PDB/Raw/PDBStream.h"
+#include "llvm/Support/Endian.h"
+
+namespace llvm {
+class PDBFile;
+
+class PDBDbiStream {
+  struct HeaderInfo;
+
+public:
+  PDBDbiStream(PDBFile &File);
+  ~PDBDbiStream();
+  std::error_code reload();
+
+  PdbRaw_DbiVer getDbiVersion() const;
+  uint32_t getAge() const;
+
+  bool isIncrementallyLinked() const;
+  bool hasCTypes() const;
+  bool isStripped() const;
+
+  uint16_t getBuildMajorVersion() const;
+  uint16_t getBuildMinorVersion() const;
+
+  uint32_t getPdbDllVersion() const;
+
+  uint32_t getNumberOfSymbols() const;
+
+  PDB_Machine getMachineType() const;
+
+private:
+  PDBStream Stream;
+  PDBFile &Pdb;
+  std::unique_ptr<HeaderInfo> Header;
+};
+}
+
+#endif
Index: include/llvm/DebugInfo/PDB/Raw/PDBFile.h
===================================================================
--- include/llvm/DebugInfo/PDB/Raw/PDBFile.h
+++ include/llvm/DebugInfo/PDB/Raw/PDBFile.h
@@ -20,7 +20,8 @@
 class MemoryBuffer;
 
 struct PDBFileContext;
-class PDBStream;
+class PDBDbiStream;
+class PDBInfoStream;
 
 class PDBFile {
 public:
@@ -55,10 +56,13 @@
     return BlockNumber * BlockSize;
   }
 
-  PDBStream *getPDBStream() const;
+  PDBInfoStream &getPDBInfoStream();
+  PDBDbiStream &getPDBDbiStream();
 
 private:
   std::unique_ptr<PDBFileContext> Context;
+  std::unique_ptr<PDBInfoStream> InfoStream;
+  std::unique_ptr<PDBDbiStream> DbiStream;
 };
 }
 
Index: include/llvm/DebugInfo/PDB/Raw/PDBInfoStream.h
===================================================================
--- include/llvm/DebugInfo/PDB/Raw/PDBInfoStream.h
+++ include/llvm/DebugInfo/PDB/Raw/PDBInfoStream.h
@@ -22,7 +22,7 @@
 
 class PDBInfoStream {
 public:
-  PDBInfoStream(const PDBFile &File);
+  PDBInfoStream(PDBFile &File);
 
   std::error_code reload();
 
@@ -35,7 +35,7 @@
 
 private:
   PDBStream Stream1;
-  const PDBFile &Pdb;
+  PDBFile &Pdb;
 
   // PDB file format version.  We only support VC70.  See the enumeration
   // `PdbRaw_ImplVer` for the other possible values.
Index: include/llvm/DebugInfo/PDB/Raw/PDBRawConstants.h
===================================================================
--- include/llvm/DebugInfo/PDB/Raw/PDBRawConstants.h
+++ include/llvm/DebugInfo/PDB/Raw/PDBRawConstants.h
@@ -15,16 +15,24 @@
 namespace llvm {
 
 enum PdbRaw_ImplVer : uint32_t {
-  VC2 = 19941610,
-  VC4 = 19950623,
-  VC41 = 19950814,
-  VC50 = 19960307,
-  VC98 = 19970604,
-  VC70Dep = 19990604, // deprecated
-  VC70 = 20000404,
-  VC80 = 20030901,
-  VC110 = 20091201,
-  VC140 = 20140508,
+  PdbImplVC2 = 19941610,
+  PdbImplVC4 = 19950623,
+  PdbImplVC41 = 19950814,
+  PdbImplVC50 = 19960307,
+  PdbImplVC98 = 19970604,
+  PdbImplVC70Dep = 19990604, // deprecated
+  PdbImplVC70 = 20000404,
+  PdbImplVC80 = 20030901,
+  PdbImplVC110 = 20091201,
+  PdbImplVC140 = 20140508,
+};
+
+enum PdbRaw_DbiVer : uint32_t {
+  PdbDbiVC41 = 930803,
+  PdbDbiV50 = 19960307,
+  PdbDbiV60 = 19970606,
+  PdbDbiV70 = 19990903,
+  PdbDbiV110 = 20091201
 };
 }
 
Index: lib/DebugInfo/PDB/CMakeLists.txt
===================================================================
--- lib/DebugInfo/PDB/CMakeLists.txt
+++ lib/DebugInfo/PDB/CMakeLists.txt
@@ -28,6 +28,7 @@
 
 add_pdb_impl_folder(Raw
   Raw/PDBFile.cpp
+  Raw/PDBDbiStream.cpp
   Raw/PDBInfoStream.cpp
   Raw/PDBNameMap.cpp
   Raw/PDBStream.cpp
Index: lib/DebugInfo/PDB/PDBExtras.cpp
===================================================================
--- lib/DebugInfo/PDB/PDBExtras.cpp
+++ lib/DebugInfo/PDB/PDBExtras.cpp
@@ -281,6 +281,34 @@
   return OS;
 }
 
+raw_ostream &llvm::operator<<(raw_ostream &OS, const PDB_Machine &Machine) {
+  switch (Machine) {
+    CASE_OUTPUT_ENUM_CLASS_NAME(PDB_Machine, Am33, OS)
+    CASE_OUTPUT_ENUM_CLASS_NAME(PDB_Machine, Amd64, OS)
+    CASE_OUTPUT_ENUM_CLASS_NAME(PDB_Machine, Arm, OS)
+    CASE_OUTPUT_ENUM_CLASS_NAME(PDB_Machine, ArmNT, OS)
+    CASE_OUTPUT_ENUM_CLASS_NAME(PDB_Machine, Ebc, OS)
+    CASE_OUTPUT_ENUM_CLASS_NAME(PDB_Machine, x86, OS)
+    CASE_OUTPUT_ENUM_CLASS_NAME(PDB_Machine, Ia64, OS)
+    CASE_OUTPUT_ENUM_CLASS_NAME(PDB_Machine, M32R, OS)
+    CASE_OUTPUT_ENUM_CLASS_NAME(PDB_Machine, Mips16, OS)
+    CASE_OUTPUT_ENUM_CLASS_NAME(PDB_Machine, MipsFpu, OS)
+    CASE_OUTPUT_ENUM_CLASS_NAME(PDB_Machine, MipsFpu16, OS)
+    CASE_OUTPUT_ENUM_CLASS_NAME(PDB_Machine, PowerPC, OS)
+    CASE_OUTPUT_ENUM_CLASS_NAME(PDB_Machine, PowerPCFP, OS)
+    CASE_OUTPUT_ENUM_CLASS_NAME(PDB_Machine, R4000, OS)
+    CASE_OUTPUT_ENUM_CLASS_NAME(PDB_Machine, SH3, OS)
+    CASE_OUTPUT_ENUM_CLASS_NAME(PDB_Machine, SH3DSP, OS)
+    CASE_OUTPUT_ENUM_CLASS_NAME(PDB_Machine, SH4, OS)
+    CASE_OUTPUT_ENUM_CLASS_NAME(PDB_Machine, SH5, OS)
+    CASE_OUTPUT_ENUM_CLASS_NAME(PDB_Machine, Thumb, OS)
+    CASE_OUTPUT_ENUM_CLASS_NAME(PDB_Machine, WceMipsV2, OS)
+  default:
+    OS << "Unknown";
+  }
+  return OS;
+}
+
 raw_ostream &llvm::operator<<(raw_ostream &OS, const Variant &Value) {
   switch (Value.Type) {
     case PDB_VariantType::Bool:
Index: lib/DebugInfo/PDB/Raw/PDBDbiStream.cpp
===================================================================
--- /dev/null
+++ lib/DebugInfo/PDB/Raw/PDBDbiStream.cpp
@@ -0,0 +1,137 @@
+//===- PDBDbiStream.cpp - PDB Dbi Stream (Stream 3) Access ------*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/DebugInfo/PDB/Raw/PDBDbiStream.h"
+#include "llvm/DebugInfo/PDB/Raw/PDBFile.h"
+#include "llvm/DebugInfo/PDB/Raw/PDBInfoStream.h"
+#include "llvm/DebugInfo/PDB/Raw/PDBRawConstants.h"
+
+using namespace llvm;
+
+namespace {
+// struct DbiFlags {
+//  uint16_t IncrementalLinking : 1;  // True if linked incrementally
+//  uint16_t IsStripped : 1;          // True if private symbols were stripped.
+//  uint16_t HasCTypes : 1;           // True if linked with /debug:ctypes.
+//  uint16_t Reserved : 13;
+//};
+const uint16_t FlagIncrementalMask = 0x0001;
+const uint16_t FlagStrippedMask = 0x0002;
+const uint16_t FlagHasCTypesMask = 0x0004;
+
+// struct DbiBuildNo {
+//  uint16_t MinorVersion : 8;
+//  uint16_t MajorVersion : 7;
+//  uint16_t NewVersionFormat : 1;
+//};
+const uint16_t BuildMinorMask = 0x00FF;
+const uint16_t BuildMinorShift = 0;
+
+const uint16_t BuildMajorMask = 0x7F00;
+const uint16_t BuildMajorShift = 8;
+
+const uint16_t BuildNewFormatMask = 0x8000;
+const uint16_t BuildNewFormatShift = 15;
+}
+
+struct PDBDbiStream::HeaderInfo {
+  support::ulittle32_t VersionSignature;
+  support::ulittle32_t VersionHeader;
+  support::ulittle32_t Age; // Should match PDBInfoStream.
+  support::ulittle16_t GSSyms;
+  support::ulittle16_t BuildNumber; // See DbiBuildNo structure.
+  support::ulittle16_t PSSyms;
+  support::ulittle16_t PdbDllVersion;        // version of mspdbNNN.dll
+  support::ulittle16_t SymRecords;           // Number of symbols
+  support::ulittle16_t PdbDllRbld;           // rbld number of mspdbNNN.dll
+  support::little32_t ModiSubstreamSize;     // Size of module info stream
+  support::little32_t SecContrSubstreamSize; // Size of sec. contribution stream
+  support::little32_t SectionMapSize;
+  support::little32_t FileInfoSize;
+  support::little32_t TypeServerSize;      // Size of type server map
+  support::ulittle32_t MFCTypeServerIndex; // Index of MFC Type Server
+  support::little32_t OptionalDbgHdrSize;  // Size of DbgHeader info
+  support::little32_t ECSubstreamSize;     // Size of EC stream (what is EC?)
+  support::ulittle16_t Flags;              // See DbiFlags enum.
+  support::ulittle16_t MachineType;        // See PDB_MachineType enum.
+
+  support::ulittle32_t Reserved; // Pad to 64 bytes
+};
+
+PDBDbiStream::PDBDbiStream(PDBFile &File) : Pdb(File), Stream(3, File) {
+  static_assert(sizeof(HeaderInfo) == 64, "Invalid HeaderInfo size!");
+}
+
+PDBDbiStream::~PDBDbiStream() {}
+
+std::error_code PDBDbiStream::reload() {
+  Stream.setOffset(0);
+  Header.reset(new HeaderInfo());
+
+  if (Stream.getLength() < sizeof(HeaderInfo))
+    return std::make_error_code(std::errc::illegal_byte_sequence);
+  Stream.readObject(Header.get());
+
+  if (Header->VersionSignature != -1)
+    return std::make_error_code(std::errc::illegal_byte_sequence);
+
+  // Prior to VC50 an old style header was used.  We don't support this.
+  if (Header->VersionHeader < PdbDbiV50)
+    return std::make_error_code(std::errc::not_supported);
+
+  if (Header->Age != Pdb.getPDBInfoStream().getAge())
+    return std::make_error_code(std::errc::illegal_byte_sequence);
+
+  if (Stream.getLength() !=
+      sizeof(HeaderInfo) + Header->ModiSubstreamSize +
+          Header->SecContrSubstreamSize + Header->SectionMapSize +
+          Header->FileInfoSize + Header->TypeServerSize +
+          Header->OptionalDbgHdrSize + Header->ECSubstreamSize)
+    return std::make_error_code(std::errc::illegal_byte_sequence);
+
+  return std::error_code();
+}
+
+PdbRaw_DbiVer PDBDbiStream::getDbiVersion() const {
+  uint32_t Value = Header->VersionHeader;
+  return static_cast<PdbRaw_DbiVer>(Value);
+}
+
+uint32_t PDBDbiStream::getAge() const { return Header->Age; }
+
+bool PDBDbiStream::isIncrementallyLinked() const {
+  return (Header->Flags & FlagIncrementalMask) != 0;
+}
+
+bool PDBDbiStream::hasCTypes() const {
+  return (Header->Flags & FlagHasCTypesMask) != 0;
+}
+
+bool PDBDbiStream::isStripped() const {
+  return (Header->Flags & FlagStrippedMask) != 0;
+}
+
+uint16_t PDBDbiStream::getBuildMajorVersion() const {
+  return (Header->BuildNumber & BuildMajorMask) >> BuildMajorShift;
+}
+
+uint16_t PDBDbiStream::getBuildMinorVersion() const {
+  return (Header->BuildNumber & BuildMinorMask) >> BuildMinorShift;
+}
+
+uint32_t PDBDbiStream::getPdbDllVersion() const {
+  return Header->PdbDllVersion;
+}
+
+uint32_t PDBDbiStream::getNumberOfSymbols() const { return Header->SymRecords; }
+
+PDB_Machine PDBDbiStream::getMachineType() const {
+  uint16_t Machine = Header->MachineType;
+  return static_cast<PDB_Machine>(Machine);
+}
Index: lib/DebugInfo/PDB/Raw/PDBFile.cpp
===================================================================
--- lib/DebugInfo/PDB/Raw/PDBFile.cpp
+++ lib/DebugInfo/PDB/Raw/PDBFile.cpp
@@ -9,6 +9,8 @@
 
 #include "llvm/DebugInfo/PDB/Raw/PDBFile.h"
 #include "llvm/ADT/ArrayRef.h"
+#include "llvm/DebugInfo/PDB/Raw/PDBDbiStream.h"
+#include "llvm/DebugInfo/PDB/Raw/PDBInfoStream.h"
 #include "llvm/Support/Endian.h"
 #include "llvm/Support/MemoryBuffer.h"
 
@@ -236,3 +238,19 @@
           Context->Buffer->getBufferStart() + getBlockMapOffset()),
       getNumDirectoryBlocks());
 }
+
+PDBInfoStream &PDBFile::getPDBInfoStream() {
+  if (!InfoStream) {
+    InfoStream.reset(new PDBInfoStream(*this));
+    InfoStream->reload();
+  }
+  return *InfoStream;
+}
+
+PDBDbiStream &PDBFile::getPDBDbiStream() {
+  if (!DbiStream) {
+    DbiStream.reset(new PDBDbiStream(*this));
+    DbiStream->reload();
+  }
+  return *DbiStream;
+}
Index: lib/DebugInfo/PDB/Raw/PDBInfoStream.cpp
===================================================================
--- lib/DebugInfo/PDB/Raw/PDBInfoStream.cpp
+++ lib/DebugInfo/PDB/Raw/PDBInfoStream.cpp
@@ -13,15 +13,14 @@
 
 using namespace llvm;
 
-PDBInfoStream::PDBInfoStream(const PDBFile &File)
-    : Pdb(File), Stream1(1, File) {}
+PDBInfoStream::PDBInfoStream(PDBFile &File) : Pdb(File), Stream1(1, File) {}
 
 std::error_code PDBInfoStream::reload() {
   Stream1.setOffset(0);
   support::ulittle32_t Value;
 
   Stream1.readObject(&Version);
-  if (Version < PdbRaw_ImplVer::VC70)
+  if (Version < PdbRaw_ImplVer::PdbImplVC70)
     return std::make_error_code(std::errc::not_supported);
 
   Stream1.readObject(&Value);
Index: test/DebugInfo/PDB/pdbdump-headers.test
===================================================================
--- test/DebugInfo/PDB/pdbdump-headers.test
+++ test/DebugInfo/PDB/pdbdump-headers.test
@@ -18,3 +18,13 @@
 ; CHECK:      NameStream: 13
 ; CHECK-NEXT: NameStreamSignature: effeeffe
 ; CHECK-NEXT: NameStreamVersion: 1
+
+; CHECK:      Dbi Version: 19990903
+; CHECK-NEXT: Age: 1
+; CHECK-NEXT: Incremental Linking: 1
+; CHECK-NEXT: Has CTypes: 0
+; CHECK-NEXT: Is Stripped: 0
+; CHECK-NEXT: Machine Type: x86
+; CHECK-NEXT: Number of Symbols: 8
+; CHECK-NEXT: Toolchain Version: 12.0
+; CHECK-NEXT: mspdb120.dll version: 12.0.31101
Index: tools/llvm-pdbdump/llvm-pdbdump.cpp
===================================================================
--- tools/llvm-pdbdump/llvm-pdbdump.cpp
+++ tools/llvm-pdbdump/llvm-pdbdump.cpp
@@ -35,6 +35,7 @@
 #include "llvm/DebugInfo/PDB/PDBSymbolExe.h"
 #include "llvm/DebugInfo/PDB/PDBSymbolFunc.h"
 #include "llvm/DebugInfo/PDB/PDBSymbolThunk.h"
+#include "llvm/DebugInfo/PDB/Raw/PDBDbiStream.h"
 #include "llvm/DebugInfo/PDB/Raw/PDBFile.h"
 #include "llvm/DebugInfo/PDB/Raw/PDBInfoStream.h"
 #include "llvm/DebugInfo/PDB/Raw/PDBStream.h"
@@ -234,10 +235,7 @@
     }
   }
 
-  PDBInfoStream InfoStream(File);
-  if (auto EC = InfoStream.reload())
-    reportError("", EC);
-
+  PDBInfoStream &InfoStream = File.getPDBInfoStream();
   outs() << "Version: " << InfoStream.getVersion() << '\n';
   outs() << "Signature: ";
   outs().write_hex(InfoStream.getSignature()) << '\n';
@@ -264,6 +262,22 @@
     if (NameStreamSignature != 0xeffeeffe || NameStreamVersion != 1)
       reportError("", std::make_error_code(std::errc::not_supported));
   }
+
+  PDBDbiStream &DbiStream = File.getPDBDbiStream();
+  outs() << "Dbi Version: " << DbiStream.getDbiVersion() << '\n';
+  outs() << "Age: " << DbiStream.getAge() << '\n';
+  outs() << "Incremental Linking: " << DbiStream.isIncrementallyLinked()
+         << '\n';
+  outs() << "Has CTypes: " << DbiStream.hasCTypes() << '\n';
+  outs() << "Is Stripped: " << DbiStream.isStripped() << '\n';
+  outs() << "Machine Type: " << DbiStream.getMachineType() << '\n';
+  outs() << "Number of Symbols: " << DbiStream.getNumberOfSymbols() << '\n';
+
+  uint16_t Major = DbiStream.getBuildMajorVersion();
+  uint16_t Minor = DbiStream.getBuildMinorVersion();
+  outs() << "Toolchain Version: " << Major << "." << Minor << '\n';
+  outs() << "mspdb" << Major << Minor << ".dll version: " << Major << "."
+         << Minor << "." << DbiStream.getPdbDllVersion() << '\n';
 }
 
 static void dumpInput(StringRef Path) {