diff --git a/lib/Frontend/PCHReader.cpp b/lib/Frontend/PCHReader.cpp
new file mode 100644
index 0000000..9ab3b7a
--- /dev/null
+++ b/lib/Frontend/PCHReader.cpp
@@ -0,0 +1,2816 @@
+//===--- PCHReader.cpp - Precompiled Headers Reader -------------*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+//  This file defines the PCHReader class, which reads a precompiled header.
+//
+//===----------------------------------------------------------------------===//
+
+#include "clang/Frontend/PCHReader.h"
+#include "clang/Frontend/FrontendDiagnostic.h"
+#include "clang/Frontend/Utils.h"
+#include "../Sema/Sema.h" // FIXME: move Sema headers elsewhere
+#include "clang/AST/ASTConsumer.h"
+#include "clang/AST/ASTContext.h"
+#include "clang/AST/Expr.h"
+#include "clang/AST/Type.h"
+#include "clang/AST/TypeLocVisitor.h"
+#include "clang/Lex/MacroInfo.h"
+#include "clang/Lex/Preprocessor.h"
+#include "clang/Lex/HeaderSearch.h"
+#include "clang/Basic/OnDiskHashTable.h"
+#include "clang/Basic/SourceManager.h"
+#include "clang/Basic/SourceManagerInternals.h"
+#include "clang/Basic/FileManager.h"
+#include "clang/Basic/TargetInfo.h"
+#include "clang/Basic/Version.h"
+#include "llvm/ADT/StringExtras.h"
+#include "llvm/Bitcode/BitstreamReader.h"
+#include "llvm/Support/MemoryBuffer.h"
+#include "llvm/Support/ErrorHandling.h"
+#include "llvm/System/Path.h"
+#include <algorithm>
+#include <iterator>
+#include <cstdio>
+#include <sys/stat.h>
+using namespace clang;
+
+//===----------------------------------------------------------------------===//
+// PCH reader validator implementation
+//===----------------------------------------------------------------------===//
+
+PCHReaderListener::~PCHReaderListener() {}
+
+bool
+PCHValidator::ReadLanguageOptions(const LangOptions &LangOpts) {
+  const LangOptions &PPLangOpts = PP.getLangOptions();
+#define PARSE_LANGOPT_BENIGN(Option)
+#define PARSE_LANGOPT_IMPORTANT(Option, DiagID)                    \
+  if (PPLangOpts.Option != LangOpts.Option) {                      \
+    Reader.Diag(DiagID) << LangOpts.Option << PPLangOpts.Option;   \
+    return true;                                                   \
+  }
+
+  PARSE_LANGOPT_BENIGN(Trigraphs);
+  PARSE_LANGOPT_BENIGN(BCPLComment);
+  PARSE_LANGOPT_BENIGN(DollarIdents);
+  PARSE_LANGOPT_BENIGN(AsmPreprocessor);
+  PARSE_LANGOPT_IMPORTANT(GNUMode, diag::warn_pch_gnu_extensions);
+  PARSE_LANGOPT_BENIGN(ImplicitInt);
+  PARSE_LANGOPT_BENIGN(Digraphs);
+  PARSE_LANGOPT_BENIGN(HexFloats);
+  PARSE_LANGOPT_IMPORTANT(C99, diag::warn_pch_c99);
+  PARSE_LANGOPT_IMPORTANT(Microsoft, diag::warn_pch_microsoft_extensions);
+  PARSE_LANGOPT_IMPORTANT(CPlusPlus, diag::warn_pch_cplusplus);
+  PARSE_LANGOPT_IMPORTANT(CPlusPlus0x, diag::warn_pch_cplusplus0x);
+  PARSE_LANGOPT_BENIGN(CXXOperatorName);
+  PARSE_LANGOPT_IMPORTANT(ObjC1, diag::warn_pch_objective_c);
+  PARSE_LANGOPT_IMPORTANT(ObjC2, diag::warn_pch_objective_c2);
+  PARSE_LANGOPT_IMPORTANT(ObjCNonFragileABI, diag::warn_pch_nonfragile_abi);
+  PARSE_LANGOPT_IMPORTANT(ObjCNonFragileABI2, diag::warn_pch_nonfragile_abi2);
+  PARSE_LANGOPT_BENIGN(PascalStrings);
+  PARSE_LANGOPT_BENIGN(WritableStrings);
+  PARSE_LANGOPT_IMPORTANT(LaxVectorConversions,
+                          diag::warn_pch_lax_vector_conversions);
+  PARSE_LANGOPT_IMPORTANT(AltiVec, diag::warn_pch_altivec);
+  PARSE_LANGOPT_IMPORTANT(Exceptions, diag::warn_pch_exceptions);
+  PARSE_LANGOPT_IMPORTANT(NeXTRuntime, diag::warn_pch_objc_runtime);
+  PARSE_LANGOPT_IMPORTANT(Freestanding, diag::warn_pch_freestanding);
+  PARSE_LANGOPT_IMPORTANT(NoBuiltin, diag::warn_pch_builtins);
+  PARSE_LANGOPT_IMPORTANT(ThreadsafeStatics,
+                          diag::warn_pch_thread_safe_statics);
+  PARSE_LANGOPT_IMPORTANT(POSIXThreads, diag::warn_pch_posix_threads);
+  PARSE_LANGOPT_IMPORTANT(Blocks, diag::warn_pch_blocks);
+  PARSE_LANGOPT_BENIGN(EmitAllDecls);
+  PARSE_LANGOPT_IMPORTANT(MathErrno, diag::warn_pch_math_errno);
+  PARSE_LANGOPT_IMPORTANT(OverflowChecking, diag::warn_pch_overflow_checking);
+  PARSE_LANGOPT_IMPORTANT(HeinousExtensions,
+                          diag::warn_pch_heinous_extensions);
+  // FIXME: Most of the options below are benign if the macro wasn't
+  // used. Unfortunately, this means that a PCH compiled without
+  // optimization can't be used with optimization turned on, even
+  // though the only thing that changes is whether __OPTIMIZE__ was
+  // defined... but if __OPTIMIZE__ never showed up in the header, it
+  // doesn't matter. We could consider making this some special kind
+  // of check.
+  PARSE_LANGOPT_IMPORTANT(Optimize, diag::warn_pch_optimize);
+  PARSE_LANGOPT_IMPORTANT(OptimizeSize, diag::warn_pch_optimize_size);
+  PARSE_LANGOPT_IMPORTANT(Static, diag::warn_pch_static);
+  PARSE_LANGOPT_IMPORTANT(PICLevel, diag::warn_pch_pic_level);
+  PARSE_LANGOPT_IMPORTANT(GNUInline, diag::warn_pch_gnu_inline);
+  PARSE_LANGOPT_IMPORTANT(NoInline, diag::warn_pch_no_inline);
+  PARSE_LANGOPT_IMPORTANT(AccessControl, diag::warn_pch_access_control);
+  PARSE_LANGOPT_IMPORTANT(CharIsSigned, diag::warn_pch_char_signed);
+  PARSE_LANGOPT_IMPORTANT(ShortWChar, diag::warn_pch_short_wchar);
+  if ((PPLangOpts.getGCMode() != 0) != (LangOpts.getGCMode() != 0)) {
+    Reader.Diag(diag::warn_pch_gc_mode)
+      << LangOpts.getGCMode() << PPLangOpts.getGCMode();
+    return true;
+  }
+  PARSE_LANGOPT_BENIGN(getVisibilityMode());
+  PARSE_LANGOPT_IMPORTANT(getStackProtectorMode(),
+                          diag::warn_pch_stack_protector);
+  PARSE_LANGOPT_BENIGN(InstantiationDepth);
+  PARSE_LANGOPT_IMPORTANT(OpenCL, diag::warn_pch_opencl);
+  PARSE_LANGOPT_BENIGN(CatchUndefined);
+  PARSE_LANGOPT_IMPORTANT(ElideConstructors, diag::warn_pch_elide_constructors);
+#undef PARSE_LANGOPT_IRRELEVANT
+#undef PARSE_LANGOPT_BENIGN
+
+  return false;
+}
+
+bool PCHValidator::ReadTargetTriple(llvm::StringRef Triple) {
+  if (Triple == PP.getTargetInfo().getTriple().str())
+    return false;
+
+  Reader.Diag(diag::warn_pch_target_triple)
+    << Triple << PP.getTargetInfo().getTriple().str();
+  return true;
+}
+
+bool PCHValidator::ReadPredefinesBuffer(llvm::StringRef PCHPredef,
+                                        FileID PCHBufferID,
+                                        llvm::StringRef OriginalFileName,
+                                        std::string &SuggestedPredefines) {
+  // We are in the context of an implicit include, so the predefines buffer will
+  // have a #include entry for the PCH file itself (as normalized by the
+  // preprocessor initialization). Find it and skip over it in the checking
+  // below.
+  llvm::SmallString<256> PCHInclude;
+  PCHInclude += "#include \"";
+  PCHInclude += NormalizeDashIncludePath(OriginalFileName);
+  PCHInclude += "\"\n";
+  std::pair<llvm::StringRef,llvm::StringRef> Split =
+    llvm::StringRef(PP.getPredefines()).split(PCHInclude.str());
+  llvm::StringRef Left =  Split.first, Right = Split.second;
+  assert(Left != PP.getPredefines() && "Missing PCH include entry!");
+
+  // If the predefines is equal to the joined left and right halves, we're done!
+  if (Left.size() + Right.size() == PCHPredef.size() &&
+      PCHPredef.startswith(Left) && PCHPredef.endswith(Right))
+    return false;
+
+  SourceManager &SourceMgr = PP.getSourceManager();
+
+  // The predefines buffers are different. Determine what the differences are,
+  // and whether they require us to reject the PCH file.
+  llvm::SmallVector<llvm::StringRef, 8> PCHLines;
+  PCHPredef.split(PCHLines, "\n", /*MaxSplit=*/-1, /*KeepEmpty=*/false);
+
+  llvm::SmallVector<llvm::StringRef, 8> CmdLineLines;
+  Left.split(CmdLineLines, "\n", /*MaxSplit=*/-1, /*KeepEmpty=*/false);
+  Right.split(CmdLineLines, "\n", /*MaxSplit=*/-1, /*KeepEmpty=*/false);
+
+  // Sort both sets of predefined buffer lines, since we allow some extra
+  // definitions and they may appear at any point in the output.
+  std::sort(CmdLineLines.begin(), CmdLineLines.end());
+  std::sort(PCHLines.begin(), PCHLines.end());
+
+  // Determine which predefines that were used to build the PCH file are missing
+  // from the command line.
+  std::vector<llvm::StringRef> MissingPredefines;
+  std::set_difference(PCHLines.begin(), PCHLines.end(),
+                      CmdLineLines.begin(), CmdLineLines.end(),
+                      std::back_inserter(MissingPredefines));
+
+  bool MissingDefines = false;
+  bool ConflictingDefines = false;
+  for (unsigned I = 0, N = MissingPredefines.size(); I != N; ++I) {
+    llvm::StringRef Missing = MissingPredefines[I];
+    if (!Missing.startswith("#define ")) {
+      Reader.Diag(diag::warn_pch_compiler_options_mismatch);
+      return true;
+    }
+
+    // This is a macro definition. Determine the name of the macro we're
+    // defining.
+    std::string::size_type StartOfMacroName = strlen("#define ");
+    std::string::size_type EndOfMacroName
+      = Missing.find_first_of("( \n\r", StartOfMacroName);
+    assert(EndOfMacroName != std::string::npos &&
+           "Couldn't find the end of the macro name");
+    llvm::StringRef MacroName = Missing.slice(StartOfMacroName, EndOfMacroName);
+
+    // Determine whether this macro was given a different definition on the
+    // command line.
+    std::string MacroDefStart = "#define " + MacroName.str();
+    std::string::size_type MacroDefLen = MacroDefStart.size();
+    llvm::SmallVector<llvm::StringRef, 8>::iterator ConflictPos
+      = std::lower_bound(CmdLineLines.begin(), CmdLineLines.end(),
+                         MacroDefStart);
+    for (; ConflictPos != CmdLineLines.end(); ++ConflictPos) {
+      if (!ConflictPos->startswith(MacroDefStart)) {
+        // Different macro; we're done.
+        ConflictPos = CmdLineLines.end();
+        break;
+      }
+
+      assert(ConflictPos->size() > MacroDefLen &&
+             "Invalid #define in predefines buffer?");
+      if ((*ConflictPos)[MacroDefLen] != ' ' &&
+          (*ConflictPos)[MacroDefLen] != '(')
+        continue; // Longer macro name; keep trying.
+
+      // We found a conflicting macro definition.
+      break;
+    }
+
+    if (ConflictPos != CmdLineLines.end()) {
+      Reader.Diag(diag::warn_cmdline_conflicting_macro_def)
+          << MacroName;
+
+      // Show the definition of this macro within the PCH file.
+      llvm::StringRef::size_type Offset = PCHPredef.find(Missing);
+      assert(Offset != llvm::StringRef::npos && "Unable to find macro!");
+      SourceLocation PCHMissingLoc = SourceMgr.getLocForStartOfFile(PCHBufferID)
+        .getFileLocWithOffset(Offset);
+      Reader.Diag(PCHMissingLoc, diag::note_pch_macro_defined_as) << MacroName;
+
+      ConflictingDefines = true;
+      continue;
+    }
+
+    // If the macro doesn't conflict, then we'll just pick up the macro
+    // definition from the PCH file. Warn the user that they made a mistake.
+    if (ConflictingDefines)
+      continue; // Don't complain if there are already conflicting defs
+
+    if (!MissingDefines) {
+      Reader.Diag(diag::warn_cmdline_missing_macro_defs);
+      MissingDefines = true;
+    }
+
+    // Show the definition of this macro within the PCH file.
+    llvm::StringRef::size_type Offset = PCHPredef.find(Missing);
+    assert(Offset != llvm::StringRef::npos && "Unable to find macro!");
+    SourceLocation PCHMissingLoc = SourceMgr.getLocForStartOfFile(PCHBufferID)
+      .getFileLocWithOffset(Offset);
+    Reader.Diag(PCHMissingLoc, diag::note_using_macro_def_from_pch);
+  }
+
+  if (ConflictingDefines)
+    return true;
+
+  // Determine what predefines were introduced based on command-line
+  // parameters that were not present when building the PCH
+  // file. Extra #defines are okay, so long as the identifiers being
+  // defined were not used within the precompiled header.
+  std::vector<llvm::StringRef> ExtraPredefines;
+  std::set_difference(CmdLineLines.begin(), CmdLineLines.end(),
+                      PCHLines.begin(), PCHLines.end(),
+                      std::back_inserter(ExtraPredefines));
+  for (unsigned I = 0, N = ExtraPredefines.size(); I != N; ++I) {
+    llvm::StringRef &Extra = ExtraPredefines[I];
+    if (!Extra.startswith("#define ")) {
+      Reader.Diag(diag::warn_pch_compiler_options_mismatch);
+      return true;
+    }
+
+    // This is an extra macro definition. Determine the name of the
+    // macro we're defining.
+    std::string::size_type StartOfMacroName = strlen("#define ");
+    std::string::size_type EndOfMacroName
+      = Extra.find_first_of("( \n\r", StartOfMacroName);
+    assert(EndOfMacroName != std::string::npos &&
+           "Couldn't find the end of the macro name");
+    llvm::StringRef MacroName = Extra.slice(StartOfMacroName, EndOfMacroName);
+
+    // Check whether this name was used somewhere in the PCH file. If
+    // so, defining it as a macro could change behavior, so we reject
+    // the PCH file.
+    if (IdentifierInfo *II = Reader.get(MacroName)) {
+      Reader.Diag(diag::warn_macro_name_used_in_pch) << II;
+      return true;
+    }
+
+    // Add this definition to the suggested predefines buffer.
+    SuggestedPredefines += Extra;
+    SuggestedPredefines += '\n';
+  }
+
+  // If we get here, it's because the predefines buffer had compatible
+  // contents. Accept the PCH file.
+  return false;
+}
+
+void PCHValidator::ReadHeaderFileInfo(const HeaderFileInfo &HFI) {
+  PP.getHeaderSearchInfo().setHeaderFileInfoForUID(HFI, NumHeaderInfos++);
+}
+
+void PCHValidator::ReadCounter(unsigned Value) {
+  PP.setCounterValue(Value);
+}
+
+//===----------------------------------------------------------------------===//
+// PCH reader implementation
+//===----------------------------------------------------------------------===//
+
+PCHReader::PCHReader(Preprocessor &PP, ASTContext *Context,
+                     const char *isysroot)
+  : Listener(new PCHValidator(PP, *this)), SourceMgr(PP.getSourceManager()),
+    FileMgr(PP.getFileManager()), Diags(PP.getDiagnostics()),
+    SemaObj(0), PP(&PP), Context(Context), StatCache(0), Consumer(0),
+    IdentifierTableData(0), IdentifierLookupTable(0),
+    IdentifierOffsets(0),
+    MethodPoolLookupTable(0), MethodPoolLookupTableData(0),
+    TotalSelectorsInMethodPool(0), SelectorOffsets(0),
+    TotalNumSelectors(0), Comments(0), NumComments(0), isysroot(isysroot),
+    NumStatHits(0), NumStatMisses(0),
+    NumSLocEntriesRead(0), NumStatementsRead(0),
+    NumMacrosRead(0), NumMethodPoolSelectorsRead(0), NumMethodPoolMisses(0),
+    NumLexicalDeclContextsRead(0), NumVisibleDeclContextsRead(0),
+    CurrentlyLoadingTypeOrDecl(0) {
+  RelocatablePCH = false;
+}
+
+PCHReader::PCHReader(SourceManager &SourceMgr, FileManager &FileMgr,
+                     Diagnostic &Diags, const char *isysroot)
+  : SourceMgr(SourceMgr), FileMgr(FileMgr), Diags(Diags),
+    SemaObj(0), PP(0), Context(0), StatCache(0), Consumer(0),
+    IdentifierTableData(0), IdentifierLookupTable(0),
+    IdentifierOffsets(0),
+    MethodPoolLookupTable(0), MethodPoolLookupTableData(0),
+    TotalSelectorsInMethodPool(0), SelectorOffsets(0),
+    TotalNumSelectors(0), Comments(0), NumComments(0), isysroot(isysroot),
+    NumStatHits(0), NumStatMisses(0),
+    NumSLocEntriesRead(0), NumStatementsRead(0),
+    NumMacrosRead(0), NumMethodPoolSelectorsRead(0), NumMethodPoolMisses(0),
+    NumLexicalDeclContextsRead(0), NumVisibleDeclContextsRead(0),
+    CurrentlyLoadingTypeOrDecl(0) {
+  RelocatablePCH = false;
+}
+
+PCHReader::~PCHReader() {}
+
+Expr *PCHReader::ReadDeclExpr() {
+  return dyn_cast_or_null<Expr>(ReadStmt(DeclsCursor));
+}
+
+Expr *PCHReader::ReadTypeExpr() {
+  return dyn_cast_or_null<Expr>(ReadStmt(DeclsCursor));
+}
+
+
+namespace {
+class PCHMethodPoolLookupTrait {
+  PCHReader &Reader;
+
+public:
+  typedef std::pair<ObjCMethodList, ObjCMethodList> data_type;
+
+  typedef Selector external_key_type;
+  typedef external_key_type internal_key_type;
+
+  explicit PCHMethodPoolLookupTrait(PCHReader &Reader) : Reader(Reader) { }
+
+  static bool EqualKey(const internal_key_type& a,
+                       const internal_key_type& b) {
+    return a == b;
+  }
+
+  static unsigned ComputeHash(Selector Sel) {
+    unsigned N = Sel.getNumArgs();
+    if (N == 0)
+      ++N;
+    unsigned R = 5381;
+    for (unsigned I = 0; I != N; ++I)
+      if (IdentifierInfo *II = Sel.getIdentifierInfoForSlot(I))
+        R = llvm::HashString(II->getName(), R);
+    return R;
+  }
+
+  // This hopefully will just get inlined and removed by the optimizer.
+  static const internal_key_type&
+  GetInternalKey(const external_key_type& x) { return x; }
+
+  static std::pair<unsigned, unsigned>
+  ReadKeyDataLength(const unsigned char*& d) {
+    using namespace clang::io;
+    unsigned KeyLen = ReadUnalignedLE16(d);
+    unsigned DataLen = ReadUnalignedLE16(d);
+    return std::make_pair(KeyLen, DataLen);
+  }
+
+  internal_key_type ReadKey(const unsigned char* d, unsigned) {
+    using namespace clang::io;
+    SelectorTable &SelTable = Reader.getContext()->Selectors;
+    unsigned N = ReadUnalignedLE16(d);
+    IdentifierInfo *FirstII
+      = Reader.DecodeIdentifierInfo(ReadUnalignedLE32(d));
+    if (N == 0)
+      return SelTable.getNullarySelector(FirstII);
+    else if (N == 1)
+      return SelTable.getUnarySelector(FirstII);
+
+    llvm::SmallVector<IdentifierInfo *, 16> Args;
+    Args.push_back(FirstII);
+    for (unsigned I = 1; I != N; ++I)
+      Args.push_back(Reader.DecodeIdentifierInfo(ReadUnalignedLE32(d)));
+
+    return SelTable.getSelector(N, Args.data());
+  }
+
+  data_type ReadData(Selector, const unsigned char* d, unsigned DataLen) {
+    using namespace clang::io;
+    unsigned NumInstanceMethods = ReadUnalignedLE16(d);
+    unsigned NumFactoryMethods = ReadUnalignedLE16(d);
+
+    data_type Result;
+
+    // Load instance methods
+    ObjCMethodList *Prev = 0;
+    for (unsigned I = 0; I != NumInstanceMethods; ++I) {
+      ObjCMethodDecl *Method
+        = cast<ObjCMethodDecl>(Reader.GetDecl(ReadUnalignedLE32(d)));
+      if (!Result.first.Method) {
+        // This is the first method, which is the easy case.
+        Result.first.Method = Method;
+        Prev = &Result.first;
+        continue;
+      }
+
+      Prev->Next = new ObjCMethodList(Method, 0);
+      Prev = Prev->Next;
+    }
+
+    // Load factory methods
+    Prev = 0;
+    for (unsigned I = 0; I != NumFactoryMethods; ++I) {
+      ObjCMethodDecl *Method
+        = cast<ObjCMethodDecl>(Reader.GetDecl(ReadUnalignedLE32(d)));
+      if (!Result.second.Method) {
+        // This is the first method, which is the easy case.
+        Result.second.Method = Method;
+        Prev = &Result.second;
+        continue;
+      }
+
+      Prev->Next = new ObjCMethodList(Method, 0);
+      Prev = Prev->Next;
+    }
+
+    return Result;
+  }
+};
+
+} // end anonymous namespace
+
+/// \brief The on-disk hash table used for the global method pool.
+typedef OnDiskChainedHashTable<PCHMethodPoolLookupTrait>
+  PCHMethodPoolLookupTable;
+
+namespace {
+class PCHIdentifierLookupTrait {
+  PCHReader &Reader;
+
+  // If we know the IdentifierInfo in advance, it is here and we will
+  // not build a new one. Used when deserializing information about an
+  // identifier that was constructed before the PCH file was read.
+  IdentifierInfo *KnownII;
+
+public:
+  typedef IdentifierInfo * data_type;
+
+  typedef const std::pair<const char*, unsigned> external_key_type;
+
+  typedef external_key_type internal_key_type;
+
+  explicit PCHIdentifierLookupTrait(PCHReader &Reader, IdentifierInfo *II = 0)
+    : Reader(Reader), KnownII(II) { }
+
+  static bool EqualKey(const internal_key_type& a,
+                       const internal_key_type& b) {
+    return (a.second == b.second) ? memcmp(a.first, b.first, a.second) == 0
+                                  : false;
+  }
+
+  static unsigned ComputeHash(const internal_key_type& a) {
+    return llvm::HashString(llvm::StringRef(a.first, a.second));
+  }
+
+  // This hopefully will just get inlined and removed by the optimizer.
+  static const internal_key_type&
+  GetInternalKey(const external_key_type& x) { return x; }
+
+  static std::pair<unsigned, unsigned>
+  ReadKeyDataLength(const unsigned char*& d) {
+    using namespace clang::io;
+    unsigned DataLen = ReadUnalignedLE16(d);
+    unsigned KeyLen = ReadUnalignedLE16(d);
+    return std::make_pair(KeyLen, DataLen);
+  }
+
+  static std::pair<const char*, unsigned>
+  ReadKey(const unsigned char* d, unsigned n) {
+    assert(n >= 2 && d[n-1] == '\0');
+    return std::make_pair((const char*) d, n-1);
+  }
+
+  IdentifierInfo *ReadData(const internal_key_type& k,
+                           const unsigned char* d,
+                           unsigned DataLen) {
+    using namespace clang::io;
+    pch::IdentID ID = ReadUnalignedLE32(d);
+    bool IsInteresting = ID & 0x01;
+
+    // Wipe out the "is interesting" bit.
+    ID = ID >> 1;
+
+    if (!IsInteresting) {
+      // For unintersting identifiers, just build the IdentifierInfo
+      // and associate it with the persistent ID.
+      IdentifierInfo *II = KnownII;
+      if (!II)
+        II = &Reader.getIdentifierTable().CreateIdentifierInfo(
+                                                 k.first, k.first + k.second);
+      Reader.SetIdentifierInfo(ID, II);
+      return II;
+    }
+
+    unsigned Bits = ReadUnalignedLE16(d);
+    bool CPlusPlusOperatorKeyword = Bits & 0x01;
+    Bits >>= 1;
+    bool Poisoned = Bits & 0x01;
+    Bits >>= 1;
+    bool ExtensionToken = Bits & 0x01;
+    Bits >>= 1;
+    bool hasMacroDefinition = Bits & 0x01;
+    Bits >>= 1;
+    unsigned ObjCOrBuiltinID = Bits & 0x3FF;
+    Bits >>= 10;
+
+    assert(Bits == 0 && "Extra bits in the identifier?");
+    DataLen -= 6;
+
+    // Build the IdentifierInfo itself and link the identifier ID with
+    // the new IdentifierInfo.
+    IdentifierInfo *II = KnownII;
+    if (!II)
+      II = &Reader.getIdentifierTable().CreateIdentifierInfo(
+                                                 k.first, k.first + k.second);
+    Reader.SetIdentifierInfo(ID, II);
+
+    // Set or check the various bits in the IdentifierInfo structure.
+    // FIXME: Load token IDs lazily, too?
+    II->setObjCOrBuiltinID(ObjCOrBuiltinID);
+    assert(II->isExtensionToken() == ExtensionToken &&
+           "Incorrect extension token flag");
+    (void)ExtensionToken;
+    II->setIsPoisoned(Poisoned);
+    assert(II->isCPlusPlusOperatorKeyword() == CPlusPlusOperatorKeyword &&
+           "Incorrect C++ operator keyword flag");
+    (void)CPlusPlusOperatorKeyword;
+
+    // If this identifier is a macro, deserialize the macro
+    // definition.
+    if (hasMacroDefinition) {
+      uint32_t Offset = ReadUnalignedLE32(d);
+      Reader.ReadMacroRecord(Offset);
+      DataLen -= 4;
+    }
+
+    // Read all of the declarations visible at global scope with this
+    // name.
+    if (Reader.getContext() == 0) return II;
+    if (DataLen > 0) {
+      llvm::SmallVector<uint32_t, 4> DeclIDs;
+      for (; DataLen > 0; DataLen -= 4)
+        DeclIDs.push_back(ReadUnalignedLE32(d));
+      Reader.SetGloballyVisibleDecls(II, DeclIDs);
+    }
+
+    return II;
+  }
+};
+
+} // end anonymous namespace
+
+/// \brief The on-disk hash table used to contain information about
+/// all of the identifiers in the program.
+typedef OnDiskChainedHashTable<PCHIdentifierLookupTrait>
+  PCHIdentifierLookupTable;
+
+bool PCHReader::Error(const char *Msg) {
+  unsigned DiagID = Diags.getCustomDiagID(Diagnostic::Fatal, Msg);
+  Diag(DiagID);
+  return true;
+}
+
+/// \brief Check the contents of the predefines buffer against the
+/// contents of the predefines buffer used to build the PCH file.
+///
+/// The contents of the two predefines buffers should be the same. If
+/// not, then some command-line option changed the preprocessor state
+/// and we must reject the PCH file.
+///
+/// \param PCHPredef The start of the predefines buffer in the PCH
+/// file.
+///
+/// \param PCHPredefLen The length of the predefines buffer in the PCH
+/// file.
+///
+/// \param PCHBufferID The FileID for the PCH predefines buffer.
+///
+/// \returns true if there was a mismatch (in which case the PCH file
+/// should be ignored), or false otherwise.
+bool PCHReader::CheckPredefinesBuffer(llvm::StringRef PCHPredef,
+                                      FileID PCHBufferID) {
+  if (Listener)
+    return Listener->ReadPredefinesBuffer(PCHPredef, PCHBufferID,
+                                          ActualOriginalFileName,
+                                          SuggestedPredefines);
+  return false;
+}
+
+//===----------------------------------------------------------------------===//
+// Source Manager Deserialization
+//===----------------------------------------------------------------------===//
+
+/// \brief Read the line table in the source manager block.
+/// \returns true if ther was an error.
+bool PCHReader::ParseLineTable(llvm::SmallVectorImpl<uint64_t> &Record) {
+  unsigned Idx = 0;
+  LineTableInfo &LineTable = SourceMgr.getLineTable();
+
+  // Parse the file names
+  std::map<int, int> FileIDs;
+  for (int I = 0, N = Record[Idx++]; I != N; ++I) {
+    // Extract the file name
+    unsigned FilenameLen = Record[Idx++];
+    std::string Filename(&Record[Idx], &Record[Idx] + FilenameLen);
+    Idx += FilenameLen;
+    MaybeAddSystemRootToFilename(Filename);
+    FileIDs[I] = LineTable.getLineTableFilenameID(Filename.c_str(),
+                                                  Filename.size());
+  }
+
+  // Parse the line entries
+  std::vector<LineEntry> Entries;
+  while (Idx < Record.size()) {
+    int FID = FileIDs[Record[Idx++]];
+
+    // Extract the line entries
+    unsigned NumEntries = Record[Idx++];
+    Entries.clear();
+    Entries.reserve(NumEntries);
+    for (unsigned I = 0; I != NumEntries; ++I) {
+      unsigned FileOffset = Record[Idx++];
+      unsigned LineNo = Record[Idx++];
+      int FilenameID = Record[Idx++];
+      SrcMgr::CharacteristicKind FileKind
+        = (SrcMgr::CharacteristicKind)Record[Idx++];
+      unsigned IncludeOffset = Record[Idx++];
+      Entries.push_back(LineEntry::get(FileOffset, LineNo, FilenameID,
+                                       FileKind, IncludeOffset));
+    }
+    LineTable.AddEntry(FID, Entries);
+  }
+
+  return false;
+}
+
+namespace {
+
+class PCHStatData {
+public:
+  const bool hasStat;
+  const ino_t ino;
+  const dev_t dev;
+  const mode_t mode;
+  const time_t mtime;
+  const off_t size;
+
+  PCHStatData(ino_t i, dev_t d, mode_t mo, time_t m, off_t s)
+  : hasStat(true), ino(i), dev(d), mode(mo), mtime(m), size(s) {}
+
+  PCHStatData()
+    : hasStat(false), ino(0), dev(0), mode(0), mtime(0), size(0) {}
+};
+
+class PCHStatLookupTrait {
+ public:
+  typedef const char *external_key_type;
+  typedef const char *internal_key_type;
+
+  typedef PCHStatData data_type;
+
+  static unsigned ComputeHash(const char *path) {
+    return llvm::HashString(path);
+  }
+
+  static internal_key_type GetInternalKey(const char *path) { return path; }
+
+  static bool EqualKey(internal_key_type a, internal_key_type b) {
+    return strcmp(a, b) == 0;
+  }
+
+  static std::pair<unsigned, unsigned>
+  ReadKeyDataLength(const unsigned char*& d) {
+    unsigned KeyLen = (unsigned) clang::io::ReadUnalignedLE16(d);
+    unsigned DataLen = (unsigned) *d++;
+    return std::make_pair(KeyLen + 1, DataLen);
+  }
+
+  static internal_key_type ReadKey(const unsigned char *d, unsigned) {
+    return (const char *)d;
+  }
+
+  static data_type ReadData(const internal_key_type, const unsigned char *d,
+                            unsigned /*DataLen*/) {
+    using namespace clang::io;
+
+    if (*d++ == 1)
+      return data_type();
+
+    ino_t ino = (ino_t) ReadUnalignedLE32(d);
+    dev_t dev = (dev_t) ReadUnalignedLE32(d);
+    mode_t mode = (mode_t) ReadUnalignedLE16(d);
+    time_t mtime = (time_t) ReadUnalignedLE64(d);
+    off_t size = (off_t) ReadUnalignedLE64(d);
+    return data_type(ino, dev, mode, mtime, size);
+  }
+};
+
+/// \brief stat() cache for precompiled headers.
+///
+/// This cache is very similar to the stat cache used by pretokenized
+/// headers.
+class PCHStatCache : public StatSysCallCache {
+  typedef OnDiskChainedHashTable<PCHStatLookupTrait> CacheTy;
+  CacheTy *Cache;
+
+  unsigned &NumStatHits, &NumStatMisses;
+public:
+  PCHStatCache(const unsigned char *Buckets,
+               const unsigned char *Base,
+               unsigned &NumStatHits,
+               unsigned &NumStatMisses)
+    : Cache(0), NumStatHits(NumStatHits), NumStatMisses(NumStatMisses) {
+    Cache = CacheTy::Create(Buckets, Base);
+  }
+
+  ~PCHStatCache() { delete Cache; }
+
+  int stat(const char *path, struct stat *buf) {
+    // Do the lookup for the file's data in the PCH file.
+    CacheTy::iterator I = Cache->find(path);
+
+    // If we don't get a hit in the PCH file just forward to 'stat'.
+    if (I == Cache->end()) {
+      ++NumStatMisses;
+      return StatSysCallCache::stat(path, buf);
+    }
+
+    ++NumStatHits;
+    PCHStatData Data = *I;
+
+    if (!Data.hasStat)
+      return 1;
+
+    buf->st_ino = Data.ino;
+    buf->st_dev = Data.dev;
+    buf->st_mtime = Data.mtime;
+    buf->st_mode = Data.mode;
+    buf->st_size = Data.size;
+    return 0;
+  }
+};
+} // end anonymous namespace
+
+
+/// \brief Read the source manager block
+PCHReader::PCHReadResult PCHReader::ReadSourceManagerBlock() {
+  using namespace SrcMgr;
+
+  // Set the source-location entry cursor to the current position in
+  // the stream. This cursor will be used to read the contents of the
+  // source manager block initially, and then lazily read
+  // source-location entries as needed.
+  SLocEntryCursor = Stream;
+
+  // The stream itself is going to skip over the source manager block.
+  if (Stream.SkipBlock()) {
+    Error("malformed block record in PCH file");
+    return Failure;
+  }
+
+  // Enter the source manager block.
+  if (SLocEntryCursor.EnterSubBlock(pch::SOURCE_MANAGER_BLOCK_ID)) {
+    Error("malformed source manager block record in PCH file");
+    return Failure;
+  }
+
+  RecordData Record;
+  while (true) {
+    unsigned Code = SLocEntryCursor.ReadCode();
+    if (Code == llvm::bitc::END_BLOCK) {
+      if (SLocEntryCursor.ReadBlockEnd()) {
+        Error("error at end of Source Manager block in PCH file");
+        return Failure;
+      }
+      return Success;
+    }
+
+    if (Code == llvm::bitc::ENTER_SUBBLOCK) {
+      // No known subblocks, always skip them.
+      SLocEntryCursor.ReadSubBlockID();
+      if (SLocEntryCursor.SkipBlock()) {
+        Error("malformed block record in PCH file");
+        return Failure;
+      }
+      continue;
+    }
+
+    if (Code == llvm::bitc::DEFINE_ABBREV) {
+      SLocEntryCursor.ReadAbbrevRecord();
+      continue;
+    }
+
+    // Read a record.
+    const char *BlobStart;
+    unsigned BlobLen;
+    Record.clear();
+    switch (SLocEntryCursor.ReadRecord(Code, Record, &BlobStart, &BlobLen)) {
+    default:  // Default behavior: ignore.
+      break;
+
+    case pch::SM_LINE_TABLE:
+      if (ParseLineTable(Record))
+        return Failure;
+      break;
+
+    case pch::SM_HEADER_FILE_INFO: {
+      HeaderFileInfo HFI;
+      HFI.isImport = Record[0];
+      HFI.DirInfo = Record[1];
+      HFI.NumIncludes = Record[2];
+      HFI.ControllingMacroID = Record[3];
+      if (Listener)
+        Listener->ReadHeaderFileInfo(HFI);
+      break;
+    }
+
+    case pch::SM_SLOC_FILE_ENTRY:
+    case pch::SM_SLOC_BUFFER_ENTRY:
+    case pch::SM_SLOC_INSTANTIATION_ENTRY:
+      // Once we hit one of the source location entries, we're done.
+      return Success;
+    }
+  }
+}
+
+/// \brief Read in the source location entry with the given ID.
+PCHReader::PCHReadResult PCHReader::ReadSLocEntryRecord(unsigned ID) {
+  if (ID == 0)
+    return Success;
+
+  if (ID > TotalNumSLocEntries) {
+    Error("source location entry ID out-of-range for PCH file");
+    return Failure;
+  }
+
+  ++NumSLocEntriesRead;
+  SLocEntryCursor.JumpToBit(SLocOffsets[ID - 1]);
+  unsigned Code = SLocEntryCursor.ReadCode();
+  if (Code == llvm::bitc::END_BLOCK ||
+      Code == llvm::bitc::ENTER_SUBBLOCK ||
+      Code == llvm::bitc::DEFINE_ABBREV) {
+    Error("incorrectly-formatted source location entry in PCH file");
+    return Failure;
+  }
+
+  RecordData Record;
+  const char *BlobStart;
+  unsigned BlobLen;
+  switch (SLocEntryCursor.ReadRecord(Code, Record, &BlobStart, &BlobLen)) {
+  default:
+    Error("incorrectly-formatted source location entry in PCH file");
+    return Failure;
+
+  case pch::SM_SLOC_FILE_ENTRY: {
+    std::string Filename(BlobStart, BlobStart + BlobLen);
+    MaybeAddSystemRootToFilename(Filename);
+    const FileEntry *File = FileMgr.getFile(Filename);
+    if (File == 0) {
+      std::string ErrorStr = "could not find file '";
+      ErrorStr += Filename;
+      ErrorStr += "' referenced by PCH file";
+      Error(ErrorStr.c_str());
+      return Failure;
+    }
+
+    FileID FID = SourceMgr.createFileID(File,
+                                SourceLocation::getFromRawEncoding(Record[1]),
+                                       (SrcMgr::CharacteristicKind)Record[2],
+                                        ID, Record[0]);
+    if (Record[3])
+      const_cast<SrcMgr::FileInfo&>(SourceMgr.getSLocEntry(FID).getFile())
+        .setHasLineDirectives();
+
+    break;
+  }
+
+  case pch::SM_SLOC_BUFFER_ENTRY: {
+    const char *Name = BlobStart;
+    unsigned Offset = Record[0];
+    unsigned Code = SLocEntryCursor.ReadCode();
+    Record.clear();
+    unsigned RecCode
+      = SLocEntryCursor.ReadRecord(Code, Record, &BlobStart, &BlobLen);
+    assert(RecCode == pch::SM_SLOC_BUFFER_BLOB && "Ill-formed PCH file");
+    (void)RecCode;
+    llvm::MemoryBuffer *Buffer
+      = llvm::MemoryBuffer::getMemBuffer(BlobStart,
+                                         BlobStart + BlobLen - 1,
+                                         Name);
+    FileID BufferID = SourceMgr.createFileIDForMemBuffer(Buffer, ID, Offset);
+
+    if (strcmp(Name, "<built-in>") == 0) {
+      PCHPredefinesBufferID = BufferID;
+      PCHPredefines = BlobStart;
+      PCHPredefinesLen = BlobLen - 1;
+    }
+
+    break;
+  }
+
+  case pch::SM_SLOC_INSTANTIATION_ENTRY: {
+    SourceLocation SpellingLoc
+      = SourceLocation::getFromRawEncoding(Record[1]);
+    SourceMgr.createInstantiationLoc(SpellingLoc,
+                              SourceLocation::getFromRawEncoding(Record[2]),
+                              SourceLocation::getFromRawEncoding(Record[3]),
+                                     Record[4],
+                                     ID,
+                                     Record[0]);
+    break;
+  }
+  }
+
+  return Success;
+}
+
+/// ReadBlockAbbrevs - Enter a subblock of the specified BlockID with the
+/// specified cursor.  Read the abbreviations that are at the top of the block
+/// and then leave the cursor pointing into the block.
+bool PCHReader::ReadBlockAbbrevs(llvm::BitstreamCursor &Cursor,
+                                 unsigned BlockID) {
+  if (Cursor.EnterSubBlock(BlockID)) {
+    Error("malformed block record in PCH file");
+    return Failure;
+  }
+
+  while (true) {
+    unsigned Code = Cursor.ReadCode();
+
+    // We expect all abbrevs to be at the start of the block.
+    if (Code != llvm::bitc::DEFINE_ABBREV)
+      return false;
+    Cursor.ReadAbbrevRecord();
+  }
+}
+
+void PCHReader::ReadMacroRecord(uint64_t Offset) {
+  assert(PP && "Forgot to set Preprocessor ?");
+
+  // Keep track of where we are in the stream, then jump back there
+  // after reading this macro.
+  SavedStreamPosition SavedPosition(Stream);
+
+  Stream.JumpToBit(Offset);
+  RecordData Record;
+  llvm::SmallVector<IdentifierInfo*, 16> MacroArgs;
+  MacroInfo *Macro = 0;
+
+  while (true) {
+    unsigned Code = Stream.ReadCode();
+    switch (Code) {
+    case llvm::bitc::END_BLOCK:
+      return;
+
+    case llvm::bitc::ENTER_SUBBLOCK:
+      // No known subblocks, always skip them.
+      Stream.ReadSubBlockID();
+      if (Stream.SkipBlock()) {
+        Error("malformed block record in PCH file");
+        return;
+      }
+      continue;
+
+    case llvm::bitc::DEFINE_ABBREV:
+      Stream.ReadAbbrevRecord();
+      continue;
+    default: break;
+    }
+
+    // Read a record.
+    Record.clear();
+    pch::PreprocessorRecordTypes RecType =
+      (pch::PreprocessorRecordTypes)Stream.ReadRecord(Code, Record);
+    switch (RecType) {
+    case pch::PP_MACRO_OBJECT_LIKE:
+    case pch::PP_MACRO_FUNCTION_LIKE: {
+      // If we already have a macro, that means that we've hit the end
+      // of the definition of the macro we were looking for. We're
+      // done.
+      if (Macro)
+        return;
+
+      IdentifierInfo *II = DecodeIdentifierInfo(Record[0]);
+      if (II == 0) {
+        Error("macro must have a name in PCH file");
+        return;
+      }
+      SourceLocation Loc = SourceLocation::getFromRawEncoding(Record[1]);
+      bool isUsed = Record[2];
+
+      MacroInfo *MI = PP->AllocateMacroInfo(Loc);
+      MI->setIsUsed(isUsed);
+
+      if (RecType == pch::PP_MACRO_FUNCTION_LIKE) {
+        // Decode function-like macro info.
+        bool isC99VarArgs = Record[3];
+        bool isGNUVarArgs = Record[4];
+        MacroArgs.clear();
+        unsigned NumArgs = Record[5];
+        for (unsigned i = 0; i != NumArgs; ++i)
+          MacroArgs.push_back(DecodeIdentifierInfo(Record[6+i]));
+
+        // Install function-like macro info.
+        MI->setIsFunctionLike();
+        if (isC99VarArgs) MI->setIsC99Varargs();
+        if (isGNUVarArgs) MI->setIsGNUVarargs();
+        MI->setArgumentList(MacroArgs.data(), MacroArgs.size(),
+                            PP->getPreprocessorAllocator());
+      }
+
+      // Finally, install the macro.
+      PP->setMacroInfo(II, MI);
+
+      // Remember that we saw this macro last so that we add the tokens that
+      // form its body to it.
+      Macro = MI;
+      ++NumMacrosRead;
+      break;
+    }
+
+    case pch::PP_TOKEN: {
+      // If we see a TOKEN before a PP_MACRO_*, then the file is
+      // erroneous, just pretend we didn't see this.
+      if (Macro == 0) break;
+
+      Token Tok;
+      Tok.startToken();
+      Tok.setLocation(SourceLocation::getFromRawEncoding(Record[0]));
+      Tok.setLength(Record[1]);
+      if (IdentifierInfo *II = DecodeIdentifierInfo(Record[2]))
+        Tok.setIdentifierInfo(II);
+      Tok.setKind((tok::TokenKind)Record[3]);
+      Tok.setFlag((Token::TokenFlags)Record[4]);
+      Macro->AddTokenToBody(Tok);
+      break;
+    }
+  }
+  }
+}
+
+void PCHReader::ReadDefinedMacros() {
+  // If there was no preprocessor block, do nothing.
+  if (!MacroCursor.getBitStreamReader())
+    return;
+  
+  llvm::BitstreamCursor Cursor = MacroCursor;
+  if (Cursor.EnterSubBlock(pch::PREPROCESSOR_BLOCK_ID)) {
+    Error("malformed preprocessor block record in PCH file");
+    return;
+  }
+  
+  RecordData Record;
+  while (true) {
+    unsigned Code = Cursor.ReadCode();
+    if (Code == llvm::bitc::END_BLOCK) {
+      if (Cursor.ReadBlockEnd())
+        Error("error at end of preprocessor block in PCH file");
+      return;
+    }
+    
+    if (Code == llvm::bitc::ENTER_SUBBLOCK) {
+      // No known subblocks, always skip them.
+      Cursor.ReadSubBlockID();
+      if (Cursor.SkipBlock()) {
+        Error("malformed block record in PCH file");
+        return;
+      }
+      continue;
+    }
+    
+    if (Code == llvm::bitc::DEFINE_ABBREV) {
+      Cursor.ReadAbbrevRecord();
+      continue;
+    }
+    
+    // Read a record.
+    const char *BlobStart;
+    unsigned BlobLen;
+    Record.clear();
+    switch (Cursor.ReadRecord(Code, Record, &BlobStart, &BlobLen)) {
+    default:  // Default behavior: ignore.
+      break;
+        
+    case pch::PP_MACRO_OBJECT_LIKE:
+    case pch::PP_MACRO_FUNCTION_LIKE:
+        DecodeIdentifierInfo(Record[0]);
+      break;
+
+    case pch::PP_TOKEN:
+      // Ignore tokens.
+      break;
+    }
+  }
+}
+
+/// \brief If we are loading a relocatable PCH file, and the filename is
+/// not an absolute path, add the system root to the beginning of the file
+/// name.
+void PCHReader::MaybeAddSystemRootToFilename(std::string &Filename) {
+  // If this is not a relocatable PCH file, there's nothing to do.
+  if (!RelocatablePCH)
+    return;
+
+  if (Filename.empty() || llvm::sys::Path(Filename).isAbsolute())
+    return;
+
+  if (isysroot == 0) {
+    // If no system root was given, default to '/'
+    Filename.insert(Filename.begin(), '/');
+    return;
+  }
+
+  unsigned Length = strlen(isysroot);
+  if (isysroot[Length - 1] != '/')
+    Filename.insert(Filename.begin(), '/');
+
+  Filename.insert(Filename.begin(), isysroot, isysroot + Length);
+}
+
+PCHReader::PCHReadResult
+PCHReader::ReadPCHBlock() {
+  if (Stream.EnterSubBlock(pch::PCH_BLOCK_ID)) {
+    Error("malformed block record in PCH file");
+    return Failure;
+  }
+
+  // Read all of the records and blocks for the PCH file.
+  RecordData Record;
+  while (!Stream.AtEndOfStream()) {
+    unsigned Code = Stream.ReadCode();
+    if (Code == llvm::bitc::END_BLOCK) {
+      if (Stream.ReadBlockEnd()) {
+        Error("error at end of module block in PCH file");
+        return Failure;
+      }
+
+      return Success;
+    }
+
+    if (Code == llvm::bitc::ENTER_SUBBLOCK) {
+      switch (Stream.ReadSubBlockID()) {
+      case pch::DECLTYPES_BLOCK_ID:
+        // We lazily load the decls block, but we want to set up the
+        // DeclsCursor cursor to point into it.  Clone our current bitcode
+        // cursor to it, enter the block and read the abbrevs in that block.
+        // With the main cursor, we just skip over it.
+        DeclsCursor = Stream;
+        if (Stream.SkipBlock() ||  // Skip with the main cursor.
+            // Read the abbrevs.
+            ReadBlockAbbrevs(DeclsCursor, pch::DECLTYPES_BLOCK_ID)) {
+          Error("malformed block record in PCH file");
+          return Failure;
+        }
+        break;
+
+      case pch::PREPROCESSOR_BLOCK_ID:
+        MacroCursor = Stream;
+        if (PP)
+          PP->setExternalSource(this);
+
+        if (Stream.SkipBlock()) {
+          Error("malformed block record in PCH file");
+          return Failure;
+        }
+        break;
+
+      case pch::SOURCE_MANAGER_BLOCK_ID:
+        switch (ReadSourceManagerBlock()) {
+        case Success:
+          break;
+
+        case Failure:
+          Error("malformed source manager block in PCH file");
+          return Failure;
+
+        case IgnorePCH:
+          return IgnorePCH;
+        }
+        break;
+      }
+      continue;
+    }
+
+    if (Code == llvm::bitc::DEFINE_ABBREV) {
+      Stream.ReadAbbrevRecord();
+      continue;
+    }
+
+    // Read and process a record.
+    Record.clear();
+    const char *BlobStart = 0;
+    unsigned BlobLen = 0;
+    switch ((pch::PCHRecordTypes)Stream.ReadRecord(Code, Record,
+                                                   &BlobStart, &BlobLen)) {
+    default:  // Default behavior: ignore.
+      break;
+
+    case pch::TYPE_OFFSET:
+      if (!TypesLoaded.empty()) {
+        Error("duplicate TYPE_OFFSET record in PCH file");
+        return Failure;
+      }
+      TypeOffsets = (const uint32_t *)BlobStart;
+      TypesLoaded.resize(Record[0]);
+      break;
+
+    case pch::DECL_OFFSET:
+      if (!DeclsLoaded.empty()) {
+        Error("duplicate DECL_OFFSET record in PCH file");
+        return Failure;
+      }
+      DeclOffsets = (const uint32_t *)BlobStart;
+      DeclsLoaded.resize(Record[0]);
+      break;
+
+    case pch::LANGUAGE_OPTIONS:
+      if (ParseLanguageOptions(Record))
+        return IgnorePCH;
+      break;
+
+    case pch::METADATA: {
+      if (Record[0] != pch::VERSION_MAJOR) {
+        Diag(Record[0] < pch::VERSION_MAJOR? diag::warn_pch_version_too_old
+                                           : diag::warn_pch_version_too_new);
+        return IgnorePCH;
+      }
+
+      RelocatablePCH = Record[4];
+      if (Listener) {
+        std::string TargetTriple(BlobStart, BlobLen);
+        if (Listener->ReadTargetTriple(TargetTriple))
+          return IgnorePCH;
+      }
+      break;
+    }
+
+    case pch::IDENTIFIER_TABLE:
+      IdentifierTableData = BlobStart;
+      if (Record[0]) {
+        IdentifierLookupTable
+          = PCHIdentifierLookupTable::Create(
+                        (const unsigned char *)IdentifierTableData + Record[0],
+                        (const unsigned char *)IdentifierTableData,
+                        PCHIdentifierLookupTrait(*this));
+        if (PP)
+          PP->getIdentifierTable().setExternalIdentifierLookup(this);
+      }
+      break;
+
+    case pch::IDENTIFIER_OFFSET:
+      if (!IdentifiersLoaded.empty()) {
+        Error("duplicate IDENTIFIER_OFFSET record in PCH file");
+        return Failure;
+      }
+      IdentifierOffsets = (const uint32_t *)BlobStart;
+      IdentifiersLoaded.resize(Record[0]);
+      if (PP)
+        PP->getHeaderSearchInfo().SetExternalLookup(this);
+      break;
+
+    case pch::EXTERNAL_DEFINITIONS:
+      if (!ExternalDefinitions.empty()) {
+        Error("duplicate EXTERNAL_DEFINITIONS record in PCH file");
+        return Failure;
+      }
+      ExternalDefinitions.swap(Record);
+      break;
+
+    case pch::SPECIAL_TYPES:
+      SpecialTypes.swap(Record);
+      break;
+
+    case pch::STATISTICS:
+      TotalNumStatements = Record[0];
+      TotalNumMacros = Record[1];
+      TotalLexicalDeclContexts = Record[2];
+      TotalVisibleDeclContexts = Record[3];
+      break;
+
+    case pch::TENTATIVE_DEFINITIONS:
+      if (!TentativeDefinitions.empty()) {
+        Error("duplicate TENTATIVE_DEFINITIONS record in PCH file");
+        return Failure;
+      }
+      TentativeDefinitions.swap(Record);
+      break;
+
+    case pch::LOCALLY_SCOPED_EXTERNAL_DECLS:
+      if (!LocallyScopedExternalDecls.empty()) {
+        Error("duplicate LOCALLY_SCOPED_EXTERNAL_DECLS record in PCH file");
+        return Failure;
+      }
+      LocallyScopedExternalDecls.swap(Record);
+      break;
+
+    case pch::SELECTOR_OFFSETS:
+      SelectorOffsets = (const uint32_t *)BlobStart;
+      TotalNumSelectors = Record[0];
+      SelectorsLoaded.resize(TotalNumSelectors);
+      break;
+
+    case pch::METHOD_POOL:
+      MethodPoolLookupTableData = (const unsigned char *)BlobStart;
+      if (Record[0])
+        MethodPoolLookupTable
+          = PCHMethodPoolLookupTable::Create(
+                        MethodPoolLookupTableData + Record[0],
+                        MethodPoolLookupTableData,
+                        PCHMethodPoolLookupTrait(*this));
+      TotalSelectorsInMethodPool = Record[1];
+      break;
+
+    case pch::PP_COUNTER_VALUE:
+      if (!Record.empty() && Listener)
+        Listener->ReadCounter(Record[0]);
+      break;
+
+    case pch::SOURCE_LOCATION_OFFSETS:
+      SLocOffsets = (const uint32_t *)BlobStart;
+      TotalNumSLocEntries = Record[0];
+      SourceMgr.PreallocateSLocEntries(this, TotalNumSLocEntries, Record[1]);
+      break;
+
+    case pch::SOURCE_LOCATION_PRELOADS:
+      for (unsigned I = 0, N = Record.size(); I != N; ++I) {
+        PCHReadResult Result = ReadSLocEntryRecord(Record[I]);
+        if (Result != Success)
+          return Result;
+      }
+      break;
+
+    case pch::STAT_CACHE: {
+      PCHStatCache *MyStatCache = 
+        new PCHStatCache((const unsigned char *)BlobStart + Record[0],
+                         (const unsigned char *)BlobStart,
+                         NumStatHits, NumStatMisses);
+      FileMgr.addStatCache(MyStatCache);
+      StatCache = MyStatCache;
+      break;
+    }
+        
+    case pch::EXT_VECTOR_DECLS:
+      if (!ExtVectorDecls.empty()) {
+        Error("duplicate EXT_VECTOR_DECLS record in PCH file");
+        return Failure;
+      }
+      ExtVectorDecls.swap(Record);
+      break;
+
+    case pch::ORIGINAL_FILE_NAME:
+      ActualOriginalFileName.assign(BlobStart, BlobLen);
+      OriginalFileName = ActualOriginalFileName;
+      MaybeAddSystemRootToFilename(OriginalFileName);
+      break;
+
+    case pch::COMMENT_RANGES:
+      Comments = (SourceRange *)BlobStart;
+      NumComments = BlobLen / sizeof(SourceRange);
+      break;
+        
+    case pch::VERSION_CONTROL_BRANCH_REVISION: {
+      llvm::StringRef CurBranch = getClangFullRepositoryVersion();
+      llvm::StringRef PCHBranch(BlobStart, BlobLen);
+      if (CurBranch != PCHBranch) {
+        Diag(diag::warn_pch_different_branch) << PCHBranch << CurBranch;
+        return IgnorePCH;
+      }
+      break;
+    }
+    }
+  }
+  Error("premature end of bitstream in PCH file");
+  return Failure;
+}
+
+PCHReader::PCHReadResult PCHReader::ReadPCH(const std::string &FileName) {
+  // Set the PCH file name.
+  this->FileName = FileName;
+
+  // Open the PCH file.
+  //
+  // FIXME: This shouldn't be here, we should just take a raw_ostream.
+  std::string ErrStr;
+  Buffer.reset(llvm::MemoryBuffer::getFileOrSTDIN(FileName, &ErrStr));
+  if (!Buffer) {
+    Error(ErrStr.c_str());
+    return IgnorePCH;
+  }
+
+  // Initialize the stream
+  StreamFile.init((const unsigned char *)Buffer->getBufferStart(),
+                  (const unsigned char *)Buffer->getBufferEnd());
+  Stream.init(StreamFile);
+
+  // Sniff for the signature.
+  if (Stream.Read(8) != 'C' ||
+      Stream.Read(8) != 'P' ||
+      Stream.Read(8) != 'C' ||
+      Stream.Read(8) != 'H') {
+    Diag(diag::err_not_a_pch_file) << FileName;
+    return Failure;
+  }
+
+  while (!Stream.AtEndOfStream()) {
+    unsigned Code = Stream.ReadCode();
+
+    if (Code != llvm::bitc::ENTER_SUBBLOCK) {
+      Error("invalid record at top-level of PCH file");
+      return Failure;
+    }
+
+    unsigned BlockID = Stream.ReadSubBlockID();
+
+    // We only know the PCH subblock ID.
+    switch (BlockID) {
+    case llvm::bitc::BLOCKINFO_BLOCK_ID:
+      if (Stream.ReadBlockInfoBlock()) {
+        Error("malformed BlockInfoBlock in PCH file");
+        return Failure;
+      }
+      break;
+    case pch::PCH_BLOCK_ID:
+      switch (ReadPCHBlock()) {
+      case Success:
+        break;
+
+      case Failure:
+        return Failure;
+
+      case IgnorePCH:
+        // FIXME: We could consider reading through to the end of this
+        // PCH block, skipping subblocks, to see if there are other
+        // PCH blocks elsewhere.
+
+        // Clear out any preallocated source location entries, so that
+        // the source manager does not try to resolve them later.
+        SourceMgr.ClearPreallocatedSLocEntries();
+
+        // Remove the stat cache.
+        if (StatCache)
+          FileMgr.removeStatCache((PCHStatCache*)StatCache);
+
+        return IgnorePCH;
+      }
+      break;
+    default:
+      if (Stream.SkipBlock()) {
+        Error("malformed block record in PCH file");
+        return Failure;
+      }
+      break;
+    }
+  }
+
+  // Check the predefines buffer.
+  if (CheckPredefinesBuffer(llvm::StringRef(PCHPredefines, PCHPredefinesLen),
+                            PCHPredefinesBufferID))
+    return IgnorePCH;
+
+  if (PP) {
+    // Initialization of keywords and pragmas occurs before the
+    // PCH file is read, so there may be some identifiers that were
+    // loaded into the IdentifierTable before we intercepted the
+    // creation of identifiers. Iterate through the list of known
+    // identifiers and determine whether we have to establish
+    // preprocessor definitions or top-level identifier declaration
+    // chains for those identifiers.
+    //
+    // We copy the IdentifierInfo pointers to a small vector first,
+    // since de-serializing declarations or macro definitions can add
+    // new entries into the identifier table, invalidating the
+    // iterators.
+    llvm::SmallVector<IdentifierInfo *, 128> Identifiers;
+    for (IdentifierTable::iterator Id = PP->getIdentifierTable().begin(),
+                                IdEnd = PP->getIdentifierTable().end();
+         Id != IdEnd; ++Id)
+      Identifiers.push_back(Id->second);
+    PCHIdentifierLookupTable *IdTable
+      = (PCHIdentifierLookupTable *)IdentifierLookupTable;
+    for (unsigned I = 0, N = Identifiers.size(); I != N; ++I) {
+      IdentifierInfo *II = Identifiers[I];
+      // Look in the on-disk hash table for an entry for
+      PCHIdentifierLookupTrait Info(*this, II);
+      std::pair<const char*, unsigned> Key(II->getNameStart(), II->getLength());
+      PCHIdentifierLookupTable::iterator Pos = IdTable->find(Key, &Info);
+      if (Pos == IdTable->end())
+        continue;
+
+      // Dereferencing the iterator has the effect of populating the
+      // IdentifierInfo node with the various declarations it needs.
+      (void)*Pos;
+    }
+  }
+
+  if (Context)
+    InitializeContext(*Context);
+
+  return Success;
+}
+
+void PCHReader::InitializeContext(ASTContext &Ctx) {
+  Context = &Ctx;
+  assert(Context && "Passed null context!");
+
+  assert(PP && "Forgot to set Preprocessor ?");
+  PP->getIdentifierTable().setExternalIdentifierLookup(this);
+  PP->getHeaderSearchInfo().SetExternalLookup(this);
+  PP->setExternalSource(this);
+  
+  // Load the translation unit declaration
+  ReadDeclRecord(DeclOffsets[0], 0);
+
+  // Load the special types.
+  Context->setBuiltinVaListType(
+    GetType(SpecialTypes[pch::SPECIAL_TYPE_BUILTIN_VA_LIST]));
+  if (unsigned Id = SpecialTypes[pch::SPECIAL_TYPE_OBJC_ID])
+    Context->setObjCIdType(GetType(Id));
+  if (unsigned Sel = SpecialTypes[pch::SPECIAL_TYPE_OBJC_SELECTOR])
+    Context->setObjCSelType(GetType(Sel));
+  if (unsigned Proto = SpecialTypes[pch::SPECIAL_TYPE_OBJC_PROTOCOL])
+    Context->setObjCProtoType(GetType(Proto));
+  if (unsigned Class = SpecialTypes[pch::SPECIAL_TYPE_OBJC_CLASS])
+    Context->setObjCClassType(GetType(Class));
+
+  if (unsigned String = SpecialTypes[pch::SPECIAL_TYPE_CF_CONSTANT_STRING])
+    Context->setCFConstantStringType(GetType(String));
+  if (unsigned FastEnum
+        = SpecialTypes[pch::SPECIAL_TYPE_OBJC_FAST_ENUMERATION_STATE])
+    Context->setObjCFastEnumerationStateType(GetType(FastEnum));
+  if (unsigned File = SpecialTypes[pch::SPECIAL_TYPE_FILE]) {
+    QualType FileType = GetType(File);
+    assert(!FileType.isNull() && "FILE type is NULL");
+    if (const TypedefType *Typedef = FileType->getAs<TypedefType>())
+      Context->setFILEDecl(Typedef->getDecl());
+    else {
+      const TagType *Tag = FileType->getAs<TagType>();
+      assert(Tag && "Invalid FILE type in PCH file");
+      Context->setFILEDecl(Tag->getDecl());
+    }
+  }
+  if (unsigned Jmp_buf = SpecialTypes[pch::SPECIAL_TYPE_jmp_buf]) {
+    QualType Jmp_bufType = GetType(Jmp_buf);
+    assert(!Jmp_bufType.isNull() && "jmp_bug type is NULL");
+    if (const TypedefType *Typedef = Jmp_bufType->getAs<TypedefType>())
+      Context->setjmp_bufDecl(Typedef->getDecl());
+    else {
+      const TagType *Tag = Jmp_bufType->getAs<TagType>();
+      assert(Tag && "Invalid jmp_bug type in PCH file");
+      Context->setjmp_bufDecl(Tag->getDecl());
+    }
+  }
+  if (unsigned Sigjmp_buf = SpecialTypes[pch::SPECIAL_TYPE_sigjmp_buf]) {
+    QualType Sigjmp_bufType = GetType(Sigjmp_buf);
+    assert(!Sigjmp_bufType.isNull() && "sigjmp_buf type is NULL");
+    if (const TypedefType *Typedef = Sigjmp_bufType->getAs<TypedefType>())
+      Context->setsigjmp_bufDecl(Typedef->getDecl());
+    else {
+      const TagType *Tag = Sigjmp_bufType->getAs<TagType>();
+      assert(Tag && "Invalid sigjmp_buf type in PCH file");
+      Context->setsigjmp_bufDecl(Tag->getDecl());
+    }
+  }
+  if (unsigned ObjCIdRedef
+        = SpecialTypes[pch::SPECIAL_TYPE_OBJC_ID_REDEFINITION])
+    Context->ObjCIdRedefinitionType = GetType(ObjCIdRedef);
+  if (unsigned ObjCClassRedef
+      = SpecialTypes[pch::SPECIAL_TYPE_OBJC_CLASS_REDEFINITION])
+    Context->ObjCClassRedefinitionType = GetType(ObjCClassRedef);
+#if 0
+  // FIXME. Accommodate for this in several PCH/Index tests
+  if (unsigned ObjCSelRedef
+      = SpecialTypes[pch::SPECIAL_TYPE_OBJC_SEL_REDEFINITION])
+    Context->ObjCSelRedefinitionType = GetType(ObjCSelRedef);
+#endif
+  if (unsigned String = SpecialTypes[pch::SPECIAL_TYPE_BLOCK_DESCRIPTOR])
+    Context->setBlockDescriptorType(GetType(String));
+  if (unsigned String
+      = SpecialTypes[pch::SPECIAL_TYPE_BLOCK_EXTENDED_DESCRIPTOR])
+    Context->setBlockDescriptorExtendedType(GetType(String));
+}
+
+/// \brief Retrieve the name of the original source file name
+/// directly from the PCH file, without actually loading the PCH
+/// file.
+std::string PCHReader::getOriginalSourceFile(const std::string &PCHFileName,
+                                             Diagnostic &Diags) {
+  // Open the PCH file.
+  std::string ErrStr;
+  llvm::OwningPtr<llvm::MemoryBuffer> Buffer;
+  Buffer.reset(llvm::MemoryBuffer::getFile(PCHFileName.c_str(), &ErrStr));
+  if (!Buffer) {
+    Diags.Report(diag::err_fe_unable_to_read_pch_file) << ErrStr;
+    return std::string();
+  }
+
+  // Initialize the stream
+  llvm::BitstreamReader StreamFile;
+  llvm::BitstreamCursor Stream;
+  StreamFile.init((const unsigned char *)Buffer->getBufferStart(),
+                  (const unsigned char *)Buffer->getBufferEnd());
+  Stream.init(StreamFile);
+
+  // Sniff for the signature.
+  if (Stream.Read(8) != 'C' ||
+      Stream.Read(8) != 'P' ||
+      Stream.Read(8) != 'C' ||
+      Stream.Read(8) != 'H') {
+    Diags.Report(diag::err_fe_not_a_pch_file) << PCHFileName;
+    return std::string();
+  }
+
+  RecordData Record;
+  while (!Stream.AtEndOfStream()) {
+    unsigned Code = Stream.ReadCode();
+
+    if (Code == llvm::bitc::ENTER_SUBBLOCK) {
+      unsigned BlockID = Stream.ReadSubBlockID();
+
+      // We only know the PCH subblock ID.
+      switch (BlockID) {
+      case pch::PCH_BLOCK_ID:
+        if (Stream.EnterSubBlock(pch::PCH_BLOCK_ID)) {
+          Diags.Report(diag::err_fe_pch_malformed_block) << PCHFileName;
+          return std::string();
+        }
+        break;
+
+      default:
+        if (Stream.SkipBlock()) {
+          Diags.Report(diag::err_fe_pch_malformed_block) << PCHFileName;
+          return std::string();
+        }
+        break;
+      }
+      continue;
+    }
+
+    if (Code == llvm::bitc::END_BLOCK) {
+      if (Stream.ReadBlockEnd()) {
+        Diags.Report(diag::err_fe_pch_error_at_end_block) << PCHFileName;
+        return std::string();
+      }
+      continue;
+    }
+
+    if (Code == llvm::bitc::DEFINE_ABBREV) {
+      Stream.ReadAbbrevRecord();
+      continue;
+    }
+
+    Record.clear();
+    const char *BlobStart = 0;
+    unsigned BlobLen = 0;
+    if (Stream.ReadRecord(Code, Record, &BlobStart, &BlobLen)
+          == pch::ORIGINAL_FILE_NAME)
+      return std::string(BlobStart, BlobLen);
+  }
+
+  return std::string();
+}
+
+/// \brief Parse the record that corresponds to a LangOptions data
+/// structure.
+///
+/// This routine compares the language options used to generate the
+/// PCH file against the language options set for the current
+/// compilation. For each option, we classify differences between the
+/// two compiler states as either "benign" or "important". Benign
+/// differences don't matter, and we accept them without complaint
+/// (and without modifying the language options). Differences between
+/// the states for important options cause the PCH file to be
+/// unusable, so we emit a warning and return true to indicate that
+/// there was an error.
+///
+/// \returns true if the PCH file is unacceptable, false otherwise.
+bool PCHReader::ParseLanguageOptions(
+                             const llvm::SmallVectorImpl<uint64_t> &Record) {
+  if (Listener) {
+    LangOptions LangOpts;
+
+  #define PARSE_LANGOPT(Option)                  \
+      LangOpts.Option = Record[Idx];             \
+      ++Idx
+
+    unsigned Idx = 0;
+    PARSE_LANGOPT(Trigraphs);
+    PARSE_LANGOPT(BCPLComment);
+    PARSE_LANGOPT(DollarIdents);
+    PARSE_LANGOPT(AsmPreprocessor);
+    PARSE_LANGOPT(GNUMode);
+    PARSE_LANGOPT(ImplicitInt);
+    PARSE_LANGOPT(Digraphs);
+    PARSE_LANGOPT(HexFloats);
+    PARSE_LANGOPT(C99);
+    PARSE_LANGOPT(Microsoft);
+    PARSE_LANGOPT(CPlusPlus);
+    PARSE_LANGOPT(CPlusPlus0x);
+    PARSE_LANGOPT(CXXOperatorNames);
+    PARSE_LANGOPT(ObjC1);
+    PARSE_LANGOPT(ObjC2);
+    PARSE_LANGOPT(ObjCNonFragileABI);
+    PARSE_LANGOPT(ObjCNonFragileABI2);
+    PARSE_LANGOPT(PascalStrings);
+    PARSE_LANGOPT(WritableStrings);
+    PARSE_LANGOPT(LaxVectorConversions);
+    PARSE_LANGOPT(AltiVec);
+    PARSE_LANGOPT(Exceptions);
+    PARSE_LANGOPT(NeXTRuntime);
+    PARSE_LANGOPT(Freestanding);
+    PARSE_LANGOPT(NoBuiltin);
+    PARSE_LANGOPT(ThreadsafeStatics);
+    PARSE_LANGOPT(POSIXThreads);
+    PARSE_LANGOPT(Blocks);
+    PARSE_LANGOPT(EmitAllDecls);
+    PARSE_LANGOPT(MathErrno);
+    PARSE_LANGOPT(OverflowChecking);
+    PARSE_LANGOPT(HeinousExtensions);
+    PARSE_LANGOPT(Optimize);
+    PARSE_LANGOPT(OptimizeSize);
+    PARSE_LANGOPT(Static);
+    PARSE_LANGOPT(PICLevel);
+    PARSE_LANGOPT(GNUInline);
+    PARSE_LANGOPT(NoInline);
+    PARSE_LANGOPT(AccessControl);
+    PARSE_LANGOPT(CharIsSigned);
+    PARSE_LANGOPT(ShortWChar);
+    LangOpts.setGCMode((LangOptions::GCMode)Record[Idx]);
+    ++Idx;
+    LangOpts.setVisibilityMode((LangOptions::VisibilityMode)Record[Idx]);
+    ++Idx;
+    LangOpts.setStackProtectorMode((LangOptions::StackProtectorMode)
+                                   Record[Idx]);
+    ++Idx;
+    PARSE_LANGOPT(InstantiationDepth);
+    PARSE_LANGOPT(OpenCL);
+    PARSE_LANGOPT(CatchUndefined);
+    // FIXME: Missing ElideConstructors?!
+  #undef PARSE_LANGOPT
+
+    return Listener->ReadLanguageOptions(LangOpts);
+  }
+
+  return false;
+}
+
+void PCHReader::ReadComments(std::vector<SourceRange> &Comments) {
+  Comments.resize(NumComments);
+  std::copy(this->Comments, this->Comments + NumComments,
+            Comments.begin());
+}
+
+/// \brief Read and return the type at the given offset.
+///
+/// This routine actually reads the record corresponding to the type
+/// at the given offset in the bitstream. It is a helper routine for
+/// GetType, which deals with reading type IDs.
+QualType PCHReader::ReadTypeRecord(uint64_t Offset) {
+  // Keep track of where we are in the stream, then jump back there
+  // after reading this type.
+  SavedStreamPosition SavedPosition(DeclsCursor);
+
+  // Note that we are loading a type record.
+  LoadingTypeOrDecl Loading(*this);
+
+  DeclsCursor.JumpToBit(Offset);
+  RecordData Record;
+  unsigned Code = DeclsCursor.ReadCode();
+  switch ((pch::TypeCode)DeclsCursor.ReadRecord(Code, Record)) {
+  case pch::TYPE_EXT_QUAL: {
+    assert(Record.size() == 2 &&
+           "Incorrect encoding of extended qualifier type");
+    QualType Base = GetType(Record[0]);
+    Qualifiers Quals = Qualifiers::fromOpaqueValue(Record[1]);
+    return Context->getQualifiedType(Base, Quals);
+  }
+
+  case pch::TYPE_COMPLEX: {
+    assert(Record.size() == 1 && "Incorrect encoding of complex type");
+    QualType ElemType = GetType(Record[0]);
+    return Context->getComplexType(ElemType);
+  }
+
+  case pch::TYPE_POINTER: {
+    assert(Record.size() == 1 && "Incorrect encoding of pointer type");
+    QualType PointeeType = GetType(Record[0]);
+    return Context->getPointerType(PointeeType);
+  }
+
+  case pch::TYPE_BLOCK_POINTER: {
+    assert(Record.size() == 1 && "Incorrect encoding of block pointer type");
+    QualType PointeeType = GetType(Record[0]);
+    return Context->getBlockPointerType(PointeeType);
+  }
+
+  case pch::TYPE_LVALUE_REFERENCE: {
+    assert(Record.size() == 1 && "Incorrect encoding of lvalue reference type");
+    QualType PointeeType = GetType(Record[0]);
+    return Context->getLValueReferenceType(PointeeType);
+  }
+
+  case pch::TYPE_RVALUE_REFERENCE: {
+    assert(Record.size() == 1 && "Incorrect encoding of rvalue reference type");
+    QualType PointeeType = GetType(Record[0]);
+    return Context->getRValueReferenceType(PointeeType);
+  }
+
+  case pch::TYPE_MEMBER_POINTER: {
+    assert(Record.size() == 1 && "Incorrect encoding of member pointer type");
+    QualType PointeeType = GetType(Record[0]);
+    QualType ClassType = GetType(Record[1]);
+    return Context->getMemberPointerType(PointeeType, ClassType.getTypePtr());
+  }
+
+  case pch::TYPE_CONSTANT_ARRAY: {
+    QualType ElementType = GetType(Record[0]);
+    ArrayType::ArraySizeModifier ASM = (ArrayType::ArraySizeModifier)Record[1];
+    unsigned IndexTypeQuals = Record[2];
+    unsigned Idx = 3;
+    llvm::APInt Size = ReadAPInt(Record, Idx);
+    return Context->getConstantArrayType(ElementType, Size,
+                                         ASM, IndexTypeQuals);
+  }
+
+  case pch::TYPE_INCOMPLETE_ARRAY: {
+    QualType ElementType = GetType(Record[0]);
+    ArrayType::ArraySizeModifier ASM = (ArrayType::ArraySizeModifier)Record[1];
+    unsigned IndexTypeQuals = Record[2];
+    return Context->getIncompleteArrayType(ElementType, ASM, IndexTypeQuals);
+  }
+
+  case pch::TYPE_VARIABLE_ARRAY: {
+    QualType ElementType = GetType(Record[0]);
+    ArrayType::ArraySizeModifier ASM = (ArrayType::ArraySizeModifier)Record[1];
+    unsigned IndexTypeQuals = Record[2];
+    SourceLocation LBLoc = SourceLocation::getFromRawEncoding(Record[3]);
+    SourceLocation RBLoc = SourceLocation::getFromRawEncoding(Record[4]);
+    return Context->getVariableArrayType(ElementType, ReadTypeExpr(),
+                                         ASM, IndexTypeQuals,
+                                         SourceRange(LBLoc, RBLoc));
+  }
+
+  case pch::TYPE_VECTOR: {
+    if (Record.size() != 4) {
+      Error("incorrect encoding of vector type in PCH file");
+      return QualType();
+    }
+
+    QualType ElementType = GetType(Record[0]);
+    unsigned NumElements = Record[1];
+    bool AltiVec = Record[2];
+    bool Pixel = Record[3];
+    return Context->getVectorType(ElementType, NumElements, AltiVec, Pixel);
+  }
+
+  case pch::TYPE_EXT_VECTOR: {
+    if (Record.size() != 4) {
+      Error("incorrect encoding of extended vector type in PCH file");
+      return QualType();
+    }
+
+    QualType ElementType = GetType(Record[0]);
+    unsigned NumElements = Record[1];
+    return Context->getExtVectorType(ElementType, NumElements);
+  }
+
+  case pch::TYPE_FUNCTION_NO_PROTO: {
+    if (Record.size() != 3) {
+      Error("incorrect encoding of no-proto function type");
+      return QualType();
+    }
+    QualType ResultType = GetType(Record[0]);
+    return Context->getFunctionNoProtoType(ResultType, Record[1],
+                                           (CallingConv)Record[2]);
+  }
+
+  case pch::TYPE_FUNCTION_PROTO: {
+    QualType ResultType = GetType(Record[0]);
+    bool NoReturn = Record[1];
+    CallingConv CallConv = (CallingConv)Record[2];
+    unsigned Idx = 3;
+    unsigned NumParams = Record[Idx++];
+    llvm::SmallVector<QualType, 16> ParamTypes;
+    for (unsigned I = 0; I != NumParams; ++I)
+      ParamTypes.push_back(GetType(Record[Idx++]));
+    bool isVariadic = Record[Idx++];
+    unsigned Quals = Record[Idx++];
+    bool hasExceptionSpec = Record[Idx++];
+    bool hasAnyExceptionSpec = Record[Idx++];
+    unsigned NumExceptions = Record[Idx++];
+    llvm::SmallVector<QualType, 2> Exceptions;
+    for (unsigned I = 0; I != NumExceptions; ++I)
+      Exceptions.push_back(GetType(Record[Idx++]));
+    return Context->getFunctionType(ResultType, ParamTypes.data(), NumParams,
+                                    isVariadic, Quals, hasExceptionSpec,
+                                    hasAnyExceptionSpec, NumExceptions,
+                                    Exceptions.data(), NoReturn, CallConv);
+  }
+
+  case pch::TYPE_UNRESOLVED_USING:
+    return Context->getTypeDeclType(
+             cast<UnresolvedUsingTypenameDecl>(GetDecl(Record[0])));
+
+  case pch::TYPE_TYPEDEF:
+    assert(Record.size() == 1 && "incorrect encoding of typedef type");
+    return Context->getTypeDeclType(cast<TypedefDecl>(GetDecl(Record[0])));
+
+  case pch::TYPE_TYPEOF_EXPR:
+    return Context->getTypeOfExprType(ReadTypeExpr());
+
+  case pch::TYPE_TYPEOF: {
+    if (Record.size() != 1) {
+      Error("incorrect encoding of typeof(type) in PCH file");
+      return QualType();
+    }
+    QualType UnderlyingType = GetType(Record[0]);
+    return Context->getTypeOfType(UnderlyingType);
+  }
+
+  case pch::TYPE_DECLTYPE:
+    return Context->getDecltypeType(ReadTypeExpr());
+
+  case pch::TYPE_RECORD:
+    assert(Record.size() == 1 && "incorrect encoding of record type");
+    return Context->getTypeDeclType(cast<RecordDecl>(GetDecl(Record[0])));
+
+  case pch::TYPE_ENUM:
+    assert(Record.size() == 1 && "incorrect encoding of enum type");
+    return Context->getTypeDeclType(cast<EnumDecl>(GetDecl(Record[0])));
+
+  case pch::TYPE_ELABORATED: {
+    assert(Record.size() == 2 && "incorrect encoding of elaborated type");
+    unsigned Tag = Record[1];
+    return Context->getElaboratedType(GetType(Record[0]),
+                                      (ElaboratedType::TagKind) Tag);
+  }
+
+  case pch::TYPE_OBJC_INTERFACE: {
+    unsigned Idx = 0;
+    ObjCInterfaceDecl *ItfD = cast<ObjCInterfaceDecl>(GetDecl(Record[Idx++]));
+    unsigned NumProtos = Record[Idx++];
+    llvm::SmallVector<ObjCProtocolDecl*, 4> Protos;
+    for (unsigned I = 0; I != NumProtos; ++I)
+      Protos.push_back(cast<ObjCProtocolDecl>(GetDecl(Record[Idx++])));
+    return Context->getObjCInterfaceType(ItfD, Protos.data(), NumProtos);
+  }
+
+  case pch::TYPE_OBJC_OBJECT_POINTER: {
+    unsigned Idx = 0;
+    QualType OIT = GetType(Record[Idx++]);
+    unsigned NumProtos = Record[Idx++];
+    llvm::SmallVector<ObjCProtocolDecl*, 4> Protos;
+    for (unsigned I = 0; I != NumProtos; ++I)
+      Protos.push_back(cast<ObjCProtocolDecl>(GetDecl(Record[Idx++])));
+    return Context->getObjCObjectPointerType(OIT, Protos.data(), NumProtos);
+  }
+
+  case pch::TYPE_SUBST_TEMPLATE_TYPE_PARM: {
+    unsigned Idx = 0;
+    QualType Parm = GetType(Record[Idx++]);
+    QualType Replacement = GetType(Record[Idx++]);
+    return
+      Context->getSubstTemplateTypeParmType(cast<TemplateTypeParmType>(Parm),
+                                            Replacement);
+  }
+  }
+  // Suppress a GCC warning
+  return QualType();
+}
+
+namespace {
+
+class TypeLocReader : public TypeLocVisitor<TypeLocReader> {
+  PCHReader &Reader;
+  const PCHReader::RecordData &Record;
+  unsigned &Idx;
+
+public:
+  TypeLocReader(PCHReader &Reader, const PCHReader::RecordData &Record,
+                unsigned &Idx)
+    : Reader(Reader), Record(Record), Idx(Idx) { }
+
+  // We want compile-time assurance that we've enumerated all of
+  // these, so unfortunately we have to declare them first, then
+  // define them out-of-line.
+#define ABSTRACT_TYPELOC(CLASS, PARENT)
+#define TYPELOC(CLASS, PARENT) \
+  void Visit##CLASS##TypeLoc(CLASS##TypeLoc TyLoc);
+#include "clang/AST/TypeLocNodes.def"
+
+  void VisitFunctionTypeLoc(FunctionTypeLoc);
+  void VisitArrayTypeLoc(ArrayTypeLoc);
+};
+
+}
+
+void TypeLocReader::VisitQualifiedTypeLoc(QualifiedTypeLoc TL) {
+  // nothing to do
+}
+void TypeLocReader::VisitBuiltinTypeLoc(BuiltinTypeLoc TL) {
+  TL.setBuiltinLoc(SourceLocation::getFromRawEncoding(Record[Idx++]));
+  if (TL.needsExtraLocalData()) {
+    TL.setWrittenTypeSpec(static_cast<DeclSpec::TST>(Record[Idx++]));
+    TL.setWrittenSignSpec(static_cast<DeclSpec::TSS>(Record[Idx++]));
+    TL.setWrittenWidthSpec(static_cast<DeclSpec::TSW>(Record[Idx++]));
+    TL.setModeAttr(Record[Idx++]);
+  }
+}
+void TypeLocReader::VisitComplexTypeLoc(ComplexTypeLoc TL) {
+  TL.setNameLoc(SourceLocation::getFromRawEncoding(Record[Idx++]));
+}
+void TypeLocReader::VisitPointerTypeLoc(PointerTypeLoc TL) {
+  TL.setStarLoc(SourceLocation::getFromRawEncoding(Record[Idx++]));
+}
+void TypeLocReader::VisitBlockPointerTypeLoc(BlockPointerTypeLoc TL) {
+  TL.setCaretLoc(SourceLocation::getFromRawEncoding(Record[Idx++]));
+}
+void TypeLocReader::VisitLValueReferenceTypeLoc(LValueReferenceTypeLoc TL) {
+  TL.setAmpLoc(SourceLocation::getFromRawEncoding(Record[Idx++]));
+}
+void TypeLocReader::VisitRValueReferenceTypeLoc(RValueReferenceTypeLoc TL) {
+  TL.setAmpAmpLoc(SourceLocation::getFromRawEncoding(Record[Idx++]));
+}
+void TypeLocReader::VisitMemberPointerTypeLoc(MemberPointerTypeLoc TL) {
+  TL.setStarLoc(SourceLocation::getFromRawEncoding(Record[Idx++]));
+}
+void TypeLocReader::VisitArrayTypeLoc(ArrayTypeLoc TL) {
+  TL.setLBracketLoc(SourceLocation::getFromRawEncoding(Record[Idx++]));
+  TL.setRBracketLoc(SourceLocation::getFromRawEncoding(Record[Idx++]));
+  if (Record[Idx++])
+    TL.setSizeExpr(Reader.ReadDeclExpr());
+  else
+    TL.setSizeExpr(0);
+}
+void TypeLocReader::VisitConstantArrayTypeLoc(ConstantArrayTypeLoc TL) {
+  VisitArrayTypeLoc(TL);
+}
+void TypeLocReader::VisitIncompleteArrayTypeLoc(IncompleteArrayTypeLoc TL) {
+  VisitArrayTypeLoc(TL);
+}
+void TypeLocReader::VisitVariableArrayTypeLoc(VariableArrayTypeLoc TL) {
+  VisitArrayTypeLoc(TL);
+}
+void TypeLocReader::VisitDependentSizedArrayTypeLoc(
+                                            DependentSizedArrayTypeLoc TL) {
+  VisitArrayTypeLoc(TL);
+}
+void TypeLocReader::VisitDependentSizedExtVectorTypeLoc(
+                                        DependentSizedExtVectorTypeLoc TL) {
+  TL.setNameLoc(SourceLocation::getFromRawEncoding(Record[Idx++]));
+}
+void TypeLocReader::VisitVectorTypeLoc(VectorTypeLoc TL) {
+  TL.setNameLoc(SourceLocation::getFromRawEncoding(Record[Idx++]));
+}
+void TypeLocReader::VisitExtVectorTypeLoc(ExtVectorTypeLoc TL) {
+  TL.setNameLoc(SourceLocation::getFromRawEncoding(Record[Idx++]));
+}
+void TypeLocReader::VisitFunctionTypeLoc(FunctionTypeLoc TL) {
+  TL.setLParenLoc(SourceLocation::getFromRawEncoding(Record[Idx++]));
+  TL.setRParenLoc(SourceLocation::getFromRawEncoding(Record[Idx++]));
+  for (unsigned i = 0, e = TL.getNumArgs(); i != e; ++i) {
+    TL.setArg(i, cast_or_null<ParmVarDecl>(Reader.GetDecl(Record[Idx++])));
+  }
+}
+void TypeLocReader::VisitFunctionProtoTypeLoc(FunctionProtoTypeLoc TL) {
+  VisitFunctionTypeLoc(TL);
+}
+void TypeLocReader::VisitFunctionNoProtoTypeLoc(FunctionNoProtoTypeLoc TL) {
+  VisitFunctionTypeLoc(TL);
+}
+void TypeLocReader::VisitUnresolvedUsingTypeLoc(UnresolvedUsingTypeLoc TL) {
+  TL.setNameLoc(SourceLocation::getFromRawEncoding(Record[Idx++]));
+}
+void TypeLocReader::VisitTypedefTypeLoc(TypedefTypeLoc TL) {
+  TL.setNameLoc(SourceLocation::getFromRawEncoding(Record[Idx++]));
+}
+void TypeLocReader::VisitTypeOfExprTypeLoc(TypeOfExprTypeLoc TL) {
+  TL.setTypeofLoc(SourceLocation::getFromRawEncoding(Record[Idx++]));
+  TL.setLParenLoc(SourceLocation::getFromRawEncoding(Record[Idx++]));
+  TL.setRParenLoc(SourceLocation::getFromRawEncoding(Record[Idx++]));
+}
+void TypeLocReader::VisitTypeOfTypeLoc(TypeOfTypeLoc TL) {
+  TL.setTypeofLoc(SourceLocation::getFromRawEncoding(Record[Idx++]));
+  TL.setLParenLoc(SourceLocation::getFromRawEncoding(Record[Idx++]));
+  TL.setRParenLoc(SourceLocation::getFromRawEncoding(Record[Idx++]));
+  TL.setUnderlyingTInfo(Reader.GetTypeSourceInfo(Record, Idx));
+}
+void TypeLocReader::VisitDecltypeTypeLoc(DecltypeTypeLoc TL) {
+  TL.setNameLoc(SourceLocation::getFromRawEncoding(Record[Idx++]));
+}
+void TypeLocReader::VisitRecordTypeLoc(RecordTypeLoc TL) {
+  TL.setNameLoc(SourceLocation::getFromRawEncoding(Record[Idx++]));
+}
+void TypeLocReader::VisitEnumTypeLoc(EnumTypeLoc TL) {
+  TL.setNameLoc(SourceLocation::getFromRawEncoding(Record[Idx++]));
+}
+void TypeLocReader::VisitElaboratedTypeLoc(ElaboratedTypeLoc TL) {
+  TL.setNameLoc(SourceLocation::getFromRawEncoding(Record[Idx++]));
+}
+void TypeLocReader::VisitTemplateTypeParmTypeLoc(TemplateTypeParmTypeLoc TL) {
+  TL.setNameLoc(SourceLocation::getFromRawEncoding(Record[Idx++]));
+}
+void TypeLocReader::VisitSubstTemplateTypeParmTypeLoc(
+                                            SubstTemplateTypeParmTypeLoc TL) {
+  TL.setNameLoc(SourceLocation::getFromRawEncoding(Record[Idx++]));
+}
+void TypeLocReader::VisitTemplateSpecializationTypeLoc(
+                                           TemplateSpecializationTypeLoc TL) {
+  TL.setTemplateNameLoc(SourceLocation::getFromRawEncoding(Record[Idx++]));
+  TL.setLAngleLoc(SourceLocation::getFromRawEncoding(Record[Idx++]));
+  TL.setRAngleLoc(SourceLocation::getFromRawEncoding(Record[Idx++]));
+  for (unsigned i = 0, e = TL.getNumArgs(); i != e; ++i)
+    TL.setArgLocInfo(i,
+        Reader.GetTemplateArgumentLocInfo(TL.getTypePtr()->getArg(i).getKind(),
+                                          Record, Idx));
+}
+void TypeLocReader::VisitQualifiedNameTypeLoc(QualifiedNameTypeLoc TL) {
+  TL.setNameLoc(SourceLocation::getFromRawEncoding(Record[Idx++]));
+}
+void TypeLocReader::VisitTypenameTypeLoc(TypenameTypeLoc TL) {
+  TL.setNameLoc(SourceLocation::getFromRawEncoding(Record[Idx++]));
+}
+void TypeLocReader::VisitObjCInterfaceTypeLoc(ObjCInterfaceTypeLoc TL) {
+  TL.setNameLoc(SourceLocation::getFromRawEncoding(Record[Idx++]));
+  TL.setLAngleLoc(SourceLocation::getFromRawEncoding(Record[Idx++]));
+  TL.setRAngleLoc(SourceLocation::getFromRawEncoding(Record[Idx++]));
+  for (unsigned i = 0, e = TL.getNumProtocols(); i != e; ++i)
+    TL.setProtocolLoc(i, SourceLocation::getFromRawEncoding(Record[Idx++]));
+}
+void TypeLocReader::VisitObjCObjectPointerTypeLoc(ObjCObjectPointerTypeLoc TL) {
+  TL.setStarLoc(SourceLocation::getFromRawEncoding(Record[Idx++]));
+  TL.setLAngleLoc(SourceLocation::getFromRawEncoding(Record[Idx++]));
+  TL.setRAngleLoc(SourceLocation::getFromRawEncoding(Record[Idx++]));
+  TL.setHasBaseTypeAsWritten(Record[Idx++]);
+  TL.setHasProtocolsAsWritten(Record[Idx++]);
+  if (TL.hasProtocolsAsWritten())
+    for (unsigned i = 0, e = TL.getNumProtocols(); i != e; ++i)
+      TL.setProtocolLoc(i, SourceLocation::getFromRawEncoding(Record[Idx++]));
+}
+
+TypeSourceInfo *PCHReader::GetTypeSourceInfo(const RecordData &Record,
+                                             unsigned &Idx) {
+  QualType InfoTy = GetType(Record[Idx++]);
+  if (InfoTy.isNull())
+    return 0;
+
+  TypeSourceInfo *TInfo = getContext()->CreateTypeSourceInfo(InfoTy);
+  TypeLocReader TLR(*this, Record, Idx);
+  for (TypeLoc TL = TInfo->getTypeLoc(); !TL.isNull(); TL = TL.getNextTypeLoc())
+    TLR.Visit(TL);
+  return TInfo;
+}
+
+QualType PCHReader::GetType(pch::TypeID ID) {
+  unsigned FastQuals = ID & Qualifiers::FastMask;
+  unsigned Index = ID >> Qualifiers::FastWidth;
+
+  if (Index < pch::NUM_PREDEF_TYPE_IDS) {
+    QualType T;
+    switch ((pch::PredefinedTypeIDs)Index) {
+    case pch::PREDEF_TYPE_NULL_ID: return QualType();
+    case pch::PREDEF_TYPE_VOID_ID: T = Context->VoidTy; break;
+    case pch::PREDEF_TYPE_BOOL_ID: T = Context->BoolTy; break;
+
+    case pch::PREDEF_TYPE_CHAR_U_ID:
+    case pch::PREDEF_TYPE_CHAR_S_ID:
+      // FIXME: Check that the signedness of CharTy is correct!
+      T = Context->CharTy;
+      break;
+
+    case pch::PREDEF_TYPE_UCHAR_ID:      T = Context->UnsignedCharTy;     break;
+    case pch::PREDEF_TYPE_USHORT_ID:     T = Context->UnsignedShortTy;    break;
+    case pch::PREDEF_TYPE_UINT_ID:       T = Context->UnsignedIntTy;      break;
+    case pch::PREDEF_TYPE_ULONG_ID:      T = Context->UnsignedLongTy;     break;
+    case pch::PREDEF_TYPE_ULONGLONG_ID:  T = Context->UnsignedLongLongTy; break;
+    case pch::PREDEF_TYPE_UINT128_ID:    T = Context->UnsignedInt128Ty;   break;
+    case pch::PREDEF_TYPE_SCHAR_ID:      T = Context->SignedCharTy;       break;
+    case pch::PREDEF_TYPE_WCHAR_ID:      T = Context->WCharTy;            break;
+    case pch::PREDEF_TYPE_SHORT_ID:      T = Context->ShortTy;            break;
+    case pch::PREDEF_TYPE_INT_ID:        T = Context->IntTy;              break;
+    case pch::PREDEF_TYPE_LONG_ID:       T = Context->LongTy;             break;
+    case pch::PREDEF_TYPE_LONGLONG_ID:   T = Context->LongLongTy;         break;
+    case pch::PREDEF_TYPE_INT128_ID:     T = Context->Int128Ty;           break;
+    case pch::PREDEF_TYPE_FLOAT_ID:      T = Context->FloatTy;            break;
+    case pch::PREDEF_TYPE_DOUBLE_ID:     T = Context->DoubleTy;           break;
+    case pch::PREDEF_TYPE_LONGDOUBLE_ID: T = Context->LongDoubleTy;       break;
+    case pch::PREDEF_TYPE_OVERLOAD_ID:   T = Context->OverloadTy;         break;
+    case pch::PREDEF_TYPE_DEPENDENT_ID:  T = Context->DependentTy;        break;
+    case pch::PREDEF_TYPE_NULLPTR_ID:    T = Context->NullPtrTy;          break;
+    case pch::PREDEF_TYPE_CHAR16_ID:     T = Context->Char16Ty;           break;
+    case pch::PREDEF_TYPE_CHAR32_ID:     T = Context->Char32Ty;           break;
+    case pch::PREDEF_TYPE_OBJC_ID:       T = Context->ObjCBuiltinIdTy;    break;
+    case pch::PREDEF_TYPE_OBJC_CLASS:    T = Context->ObjCBuiltinClassTy; break;
+    case pch::PREDEF_TYPE_OBJC_SEL:      T = Context->ObjCBuiltinSelTy;   break;
+    }
+
+    assert(!T.isNull() && "Unknown predefined type");
+    return T.withFastQualifiers(FastQuals);
+  }
+
+  Index -= pch::NUM_PREDEF_TYPE_IDS;
+  //assert(Index < TypesLoaded.size() && "Type index out-of-range");
+  if (TypesLoaded[Index].isNull())
+    TypesLoaded[Index] = ReadTypeRecord(TypeOffsets[Index]);
+
+  return TypesLoaded[Index].withFastQualifiers(FastQuals);
+}
+
+TemplateArgumentLocInfo
+PCHReader::GetTemplateArgumentLocInfo(TemplateArgument::ArgKind Kind,
+                                      const RecordData &Record,
+                                      unsigned &Index) {
+  switch (Kind) {
+  case TemplateArgument::Expression:
+    return ReadDeclExpr();
+  case TemplateArgument::Type:
+    return GetTypeSourceInfo(Record, Index);
+  case TemplateArgument::Template: {
+    SourceLocation 
+      QualStart = SourceLocation::getFromRawEncoding(Record[Index++]),
+      QualEnd = SourceLocation::getFromRawEncoding(Record[Index++]),
+      TemplateNameLoc = SourceLocation::getFromRawEncoding(Record[Index++]);
+    return TemplateArgumentLocInfo(SourceRange(QualStart, QualEnd),
+                                   TemplateNameLoc);
+  }
+  case TemplateArgument::Null:
+  case TemplateArgument::Integral:
+  case TemplateArgument::Declaration:
+  case TemplateArgument::Pack:
+    return TemplateArgumentLocInfo();
+  }
+  llvm_unreachable("unexpected template argument loc");
+  return TemplateArgumentLocInfo();
+}
+
+Decl *PCHReader::GetDecl(pch::DeclID ID) {
+  if (ID == 0)
+    return 0;
+
+  if (ID > DeclsLoaded.size()) {
+    Error("declaration ID out-of-range for PCH file");
+    return 0;
+  }
+
+  unsigned Index = ID - 1;
+  if (!DeclsLoaded[Index])
+    ReadDeclRecord(DeclOffsets[Index], Index);
+
+  return DeclsLoaded[Index];
+}
+
+/// \brief Resolve the offset of a statement into a statement.
+///
+/// This operation will read a new statement from the external
+/// source each time it is called, and is meant to be used via a
+/// LazyOffsetPtr (which is used by Decls for the body of functions, etc).
+Stmt *PCHReader::GetDeclStmt(uint64_t Offset) {
+  // Since we know tha this statement is part of a decl, make sure to use the
+  // decl cursor to read it.
+  DeclsCursor.JumpToBit(Offset);
+  return ReadStmt(DeclsCursor);
+}
+
+bool PCHReader::ReadDeclsLexicallyInContext(DeclContext *DC,
+                                  llvm::SmallVectorImpl<pch::DeclID> &Decls) {
+  assert(DC->hasExternalLexicalStorage() &&
+         "DeclContext has no lexical decls in storage");
+  uint64_t Offset = DeclContextOffsets[DC].first;
+  assert(Offset && "DeclContext has no lexical decls in storage");
+
+  // Keep track of where we are in the stream, then jump back there
+  // after reading this context.
+  SavedStreamPosition SavedPosition(DeclsCursor);
+
+  // Load the record containing all of the declarations lexically in
+  // this context.
+  DeclsCursor.JumpToBit(Offset);
+  RecordData Record;
+  unsigned Code = DeclsCursor.ReadCode();
+  unsigned RecCode = DeclsCursor.ReadRecord(Code, Record);
+  (void)RecCode;
+  assert(RecCode == pch::DECL_CONTEXT_LEXICAL && "Expected lexical block");
+
+  // Load all of the declaration IDs
+  Decls.clear();
+  Decls.insert(Decls.end(), Record.begin(), Record.end());
+  ++NumLexicalDeclContextsRead;
+  return false;
+}
+
+bool PCHReader::ReadDeclsVisibleInContext(DeclContext *DC,
+                           llvm::SmallVectorImpl<VisibleDeclaration> &Decls) {
+  assert(DC->hasExternalVisibleStorage() &&
+         "DeclContext has no visible decls in storage");
+  uint64_t Offset = DeclContextOffsets[DC].second;
+  assert(Offset && "DeclContext has no visible decls in storage");
+
+  // Keep track of where we are in the stream, then jump back there
+  // after reading this context.
+  SavedStreamPosition SavedPosition(DeclsCursor);
+
+  // Load the record containing all of the declarations visible in
+  // this context.
+  DeclsCursor.JumpToBit(Offset);
+  RecordData Record;
+  unsigned Code = DeclsCursor.ReadCode();
+  unsigned RecCode = DeclsCursor.ReadRecord(Code, Record);
+  (void)RecCode;
+  assert(RecCode == pch::DECL_CONTEXT_VISIBLE && "Expected visible block");
+  if (Record.size() == 0)
+    return false;
+
+  Decls.clear();
+
+  unsigned Idx = 0;
+  while (Idx < Record.size()) {
+    Decls.push_back(VisibleDeclaration());
+    Decls.back().Name = ReadDeclarationName(Record, Idx);
+
+    unsigned Size = Record[Idx++];
+    llvm::SmallVector<unsigned, 4> &LoadedDecls = Decls.back().Declarations;
+    LoadedDecls.reserve(Size);
+    for (unsigned I = 0; I < Size; ++I)
+      LoadedDecls.push_back(Record[Idx++]);
+  }
+
+  ++NumVisibleDeclContextsRead;
+  return false;
+}
+
+void PCHReader::StartTranslationUnit(ASTConsumer *Consumer) {
+  this->Consumer = Consumer;
+
+  if (!Consumer)
+    return;
+
+  for (unsigned I = 0, N = ExternalDefinitions.size(); I != N; ++I) {
+    // Force deserialization of this decl, which will cause it to be passed to
+    // the consumer (or queued).
+    GetDecl(ExternalDefinitions[I]);
+  }
+
+  for (unsigned I = 0, N = InterestingDecls.size(); I != N; ++I) {
+    DeclGroupRef DG(InterestingDecls[I]);
+    Consumer->HandleTopLevelDecl(DG);
+  }
+}
+
+void PCHReader::PrintStats() {
+  std::fprintf(stderr, "*** PCH Statistics:\n");
+
+  unsigned NumTypesLoaded
+    = TypesLoaded.size() - std::count(TypesLoaded.begin(), TypesLoaded.end(),
+                                      QualType());
+  unsigned NumDeclsLoaded
+    = DeclsLoaded.size() - std::count(DeclsLoaded.begin(), DeclsLoaded.end(),
+                                      (Decl *)0);
+  unsigned NumIdentifiersLoaded
+    = IdentifiersLoaded.size() - std::count(IdentifiersLoaded.begin(),
+                                            IdentifiersLoaded.end(),
+                                            (IdentifierInfo *)0);
+  unsigned NumSelectorsLoaded
+    = SelectorsLoaded.size() - std::count(SelectorsLoaded.begin(),
+                                          SelectorsLoaded.end(),
+                                          Selector());
+
+  std::fprintf(stderr, "  %u stat cache hits\n", NumStatHits);
+  std::fprintf(stderr, "  %u stat cache misses\n", NumStatMisses);
+  if (TotalNumSLocEntries)
+    std::fprintf(stderr, "  %u/%u source location entries read (%f%%)\n",
+                 NumSLocEntriesRead, TotalNumSLocEntries,
+                 ((float)NumSLocEntriesRead/TotalNumSLocEntries * 100));
+  if (!TypesLoaded.empty())
+    std::fprintf(stderr, "  %u/%u types read (%f%%)\n",
+                 NumTypesLoaded, (unsigned)TypesLoaded.size(),
+                 ((float)NumTypesLoaded/TypesLoaded.size() * 100));
+  if (!DeclsLoaded.empty())
+    std::fprintf(stderr, "  %u/%u declarations read (%f%%)\n",
+                 NumDeclsLoaded, (unsigned)DeclsLoaded.size(),
+                 ((float)NumDeclsLoaded/DeclsLoaded.size() * 100));
+  if (!IdentifiersLoaded.empty())
+    std::fprintf(stderr, "  %u/%u identifiers read (%f%%)\n",
+                 NumIdentifiersLoaded, (unsigned)IdentifiersLoaded.size(),
+                 ((float)NumIdentifiersLoaded/IdentifiersLoaded.size() * 100));
+  if (TotalNumSelectors)
+    std::fprintf(stderr, "  %u/%u selectors read (%f%%)\n",
+                 NumSelectorsLoaded, TotalNumSelectors,
+                 ((float)NumSelectorsLoaded/TotalNumSelectors * 100));
+  if (TotalNumStatements)
+    std::fprintf(stderr, "  %u/%u statements read (%f%%)\n",
+                 NumStatementsRead, TotalNumStatements,
+                 ((float)NumStatementsRead/TotalNumStatements * 100));
+  if (TotalNumMacros)
+    std::fprintf(stderr, "  %u/%u macros read (%f%%)\n",
+                 NumMacrosRead, TotalNumMacros,
+                 ((float)NumMacrosRead/TotalNumMacros * 100));
+  if (TotalLexicalDeclContexts)
+    std::fprintf(stderr, "  %u/%u lexical declcontexts read (%f%%)\n",
+                 NumLexicalDeclContextsRead, TotalLexicalDeclContexts,
+                 ((float)NumLexicalDeclContextsRead/TotalLexicalDeclContexts
+                  * 100));
+  if (TotalVisibleDeclContexts)
+    std::fprintf(stderr, "  %u/%u visible declcontexts read (%f%%)\n",
+                 NumVisibleDeclContextsRead, TotalVisibleDeclContexts,
+                 ((float)NumVisibleDeclContextsRead/TotalVisibleDeclContexts
+                  * 100));
+  if (TotalSelectorsInMethodPool) {
+    std::fprintf(stderr, "  %u/%u method pool entries read (%f%%)\n",
+                 NumMethodPoolSelectorsRead, TotalSelectorsInMethodPool,
+                 ((float)NumMethodPoolSelectorsRead/TotalSelectorsInMethodPool
+                  * 100));
+    std::fprintf(stderr, "  %u method pool misses\n", NumMethodPoolMisses);
+  }
+  std::fprintf(stderr, "\n");
+}
+
+void PCHReader::InitializeSema(Sema &S) {
+  SemaObj = &S;
+  S.ExternalSource = this;
+
+  // Makes sure any declarations that were deserialized "too early"
+  // still get added to the identifier's declaration chains.
+  for (unsigned I = 0, N = PreloadedDecls.size(); I != N; ++I) {
+    SemaObj->TUScope->AddDecl(Action::DeclPtrTy::make(PreloadedDecls[I]));
+    SemaObj->IdResolver.AddDecl(PreloadedDecls[I]);
+  }
+  PreloadedDecls.clear();
+
+  // If there were any tentative definitions, deserialize them and add
+  // them to Sema's list of tentative definitions.
+  for (unsigned I = 0, N = TentativeDefinitions.size(); I != N; ++I) {
+    VarDecl *Var = cast<VarDecl>(GetDecl(TentativeDefinitions[I]));
+    SemaObj->TentativeDefinitions.push_back(Var);
+  }
+
+  // If there were any locally-scoped external declarations,
+  // deserialize them and add them to Sema's table of locally-scoped
+  // external declarations.
+  for (unsigned I = 0, N = LocallyScopedExternalDecls.size(); I != N; ++I) {
+    NamedDecl *D = cast<NamedDecl>(GetDecl(LocallyScopedExternalDecls[I]));
+    SemaObj->LocallyScopedExternalDecls[D->getDeclName()] = D;
+  }
+
+  // If there were any ext_vector type declarations, deserialize them
+  // and add them to Sema's vector of such declarations.
+  for (unsigned I = 0, N = ExtVectorDecls.size(); I != N; ++I)
+    SemaObj->ExtVectorDecls.push_back(
+                               cast<TypedefDecl>(GetDecl(ExtVectorDecls[I])));
+}
+
+IdentifierInfo* PCHReader::get(const char *NameStart, const char *NameEnd) {
+  // Try to find this name within our on-disk hash table
+  PCHIdentifierLookupTable *IdTable
+    = (PCHIdentifierLookupTable *)IdentifierLookupTable;
+  std::pair<const char*, unsigned> Key(NameStart, NameEnd - NameStart);
+  PCHIdentifierLookupTable::iterator Pos = IdTable->find(Key);
+  if (Pos == IdTable->end())
+    return 0;
+
+  // Dereferencing the iterator has the effect of building the
+  // IdentifierInfo node and populating it with the various
+  // declarations it needs.
+  return *Pos;
+}
+
+std::pair<ObjCMethodList, ObjCMethodList>
+PCHReader::ReadMethodPool(Selector Sel) {
+  if (!MethodPoolLookupTable)
+    return std::pair<ObjCMethodList, ObjCMethodList>();
+
+  // Try to find this selector within our on-disk hash table.
+  PCHMethodPoolLookupTable *PoolTable
+    = (PCHMethodPoolLookupTable*)MethodPoolLookupTable;
+  PCHMethodPoolLookupTable::iterator Pos = PoolTable->find(Sel);
+  if (Pos == PoolTable->end()) {
+    ++NumMethodPoolMisses;
+    return std::pair<ObjCMethodList, ObjCMethodList>();;
+  }
+
+  ++NumMethodPoolSelectorsRead;
+  return *Pos;
+}
+
+void PCHReader::SetIdentifierInfo(unsigned ID, IdentifierInfo *II) {
+  assert(ID && "Non-zero identifier ID required");
+  assert(ID <= IdentifiersLoaded.size() && "identifier ID out of range");
+  IdentifiersLoaded[ID - 1] = II;
+}
+
+/// \brief Set the globally-visible declarations associated with the given
+/// identifier.
+///
+/// If the PCH reader is currently in a state where the given declaration IDs
+/// cannot safely be resolved, they are queued until it is safe to resolve
+/// them.
+///
+/// \param II an IdentifierInfo that refers to one or more globally-visible
+/// declarations.
+///
+/// \param DeclIDs the set of declaration IDs with the name @p II that are
+/// visible at global scope.
+///
+/// \param Nonrecursive should be true to indicate that the caller knows that
+/// this call is non-recursive, and therefore the globally-visible declarations
+/// will not be placed onto the pending queue.
+void
+PCHReader::SetGloballyVisibleDecls(IdentifierInfo *II,
+                              const llvm::SmallVectorImpl<uint32_t> &DeclIDs,
+                                   bool Nonrecursive) {
+  if (CurrentlyLoadingTypeOrDecl && !Nonrecursive) {
+    PendingIdentifierInfos.push_back(PendingIdentifierInfo());
+    PendingIdentifierInfo &PII = PendingIdentifierInfos.back();
+    PII.II = II;
+    for (unsigned I = 0, N = DeclIDs.size(); I != N; ++I)
+      PII.DeclIDs.push_back(DeclIDs[I]);
+    return;
+  }
+
+  for (unsigned I = 0, N = DeclIDs.size(); I != N; ++I) {
+    NamedDecl *D = cast<NamedDecl>(GetDecl(DeclIDs[I]));
+    if (SemaObj) {
+      // Introduce this declaration into the translation-unit scope
+      // and add it to the declaration chain for this identifier, so
+      // that (unqualified) name lookup will find it.
+      SemaObj->TUScope->AddDecl(Action::DeclPtrTy::make(D));
+      SemaObj->IdResolver.AddDeclToIdentifierChain(II, D);
+    } else {
+      // Queue this declaration so that it will be added to the
+      // translation unit scope and identifier's declaration chain
+      // once a Sema object is known.
+      PreloadedDecls.push_back(D);
+    }
+  }
+}
+
+IdentifierInfo *PCHReader::DecodeIdentifierInfo(unsigned ID) {
+  if (ID == 0)
+    return 0;
+
+  if (!IdentifierTableData || IdentifiersLoaded.empty()) {
+    Error("no identifier table in PCH file");
+    return 0;
+  }
+
+  assert(PP && "Forgot to set Preprocessor ?");
+  if (!IdentifiersLoaded[ID - 1]) {
+    uint32_t Offset = IdentifierOffsets[ID - 1];
+    const char *Str = IdentifierTableData + Offset;
+
+    // All of the strings in the PCH file are preceded by a 16-bit
+    // length. Extract that 16-bit length to avoid having to execute
+    // strlen().
+    // NOTE: 'StrLenPtr' is an 'unsigned char*' so that we load bytes as
+    //  unsigned integers.  This is important to avoid integer overflow when
+    //  we cast them to 'unsigned'.
+    const unsigned char *StrLenPtr = (const unsigned char*) Str - 2;
+    unsigned StrLen = (((unsigned) StrLenPtr[0])
+                       | (((unsigned) StrLenPtr[1]) << 8)) - 1;
+    IdentifiersLoaded[ID - 1]
+      = &PP->getIdentifierTable().get(Str, Str + StrLen);
+  }
+
+  return IdentifiersLoaded[ID - 1];
+}
+
+void PCHReader::ReadSLocEntry(unsigned ID) {
+  ReadSLocEntryRecord(ID);
+}
+
+Selector PCHReader::DecodeSelector(unsigned ID) {
+  if (ID == 0)
+    return Selector();
+
+  if (!MethodPoolLookupTableData)
+    return Selector();
+
+  if (ID > TotalNumSelectors) {
+    Error("selector ID out of range in PCH file");
+    return Selector();
+  }
+
+  unsigned Index = ID - 1;
+  if (SelectorsLoaded[Index].getAsOpaquePtr() == 0) {
+    // Load this selector from the selector table.
+    // FIXME: endianness portability issues with SelectorOffsets table
+    PCHMethodPoolLookupTrait Trait(*this);
+    SelectorsLoaded[Index]
+      = Trait.ReadKey(MethodPoolLookupTableData + SelectorOffsets[Index], 0);
+  }
+
+  return SelectorsLoaded[Index];
+}
+
+DeclarationName
+PCHReader::ReadDeclarationName(const RecordData &Record, unsigned &Idx) {
+  DeclarationName::NameKind Kind = (DeclarationName::NameKind)Record[Idx++];
+  switch (Kind) {
+  case DeclarationName::Identifier:
+    return DeclarationName(GetIdentifierInfo(Record, Idx));
+
+  case DeclarationName::ObjCZeroArgSelector:
+  case DeclarationName::ObjCOneArgSelector:
+  case DeclarationName::ObjCMultiArgSelector:
+    return DeclarationName(GetSelector(Record, Idx));
+
+  case DeclarationName::CXXConstructorName:
+    return Context->DeclarationNames.getCXXConstructorName(
+                          Context->getCanonicalType(GetType(Record[Idx++])));
+
+  case DeclarationName::CXXDestructorName:
+    return Context->DeclarationNames.getCXXDestructorName(
+                          Context->getCanonicalType(GetType(Record[Idx++])));
+
+  case DeclarationName::CXXConversionFunctionName:
+    return Context->DeclarationNames.getCXXConversionFunctionName(
+                          Context->getCanonicalType(GetType(Record[Idx++])));
+
+  case DeclarationName::CXXOperatorName:
+    return Context->DeclarationNames.getCXXOperatorName(
+                                       (OverloadedOperatorKind)Record[Idx++]);
+
+  case DeclarationName::CXXLiteralOperatorName:
+    return Context->DeclarationNames.getCXXLiteralOperatorName(
+                                       GetIdentifierInfo(Record, Idx));
+
+  case DeclarationName::CXXUsingDirective:
+    return DeclarationName::getUsingDirectiveName();
+  }
+
+  // Required to silence GCC warning
+  return DeclarationName();
+}
+
+/// \brief Read an integral value
+llvm::APInt PCHReader::ReadAPInt(const RecordData &Record, unsigned &Idx) {
+  unsigned BitWidth = Record[Idx++];
+  unsigned NumWords = llvm::APInt::getNumWords(BitWidth);
+  llvm::APInt Result(BitWidth, NumWords, &Record[Idx]);
+  Idx += NumWords;
+  return Result;
+}
+
+/// \brief Read a signed integral value
+llvm::APSInt PCHReader::ReadAPSInt(const RecordData &Record, unsigned &Idx) {
+  bool isUnsigned = Record[Idx++];
+  return llvm::APSInt(ReadAPInt(Record, Idx), isUnsigned);
+}
+
+/// \brief Read a floating-point value
+llvm::APFloat PCHReader::ReadAPFloat(const RecordData &Record, unsigned &Idx) {
+  return llvm::APFloat(ReadAPInt(Record, Idx));
+}
+
+// \brief Read a string
+std::string PCHReader::ReadString(const RecordData &Record, unsigned &Idx) {
+  unsigned Len = Record[Idx++];
+  std::string Result(Record.data() + Idx, Record.data() + Idx + Len);
+  Idx += Len;
+  return Result;
+}
+
+DiagnosticBuilder PCHReader::Diag(unsigned DiagID) {
+  return Diag(SourceLocation(), DiagID);
+}
+
+DiagnosticBuilder PCHReader::Diag(SourceLocation Loc, unsigned DiagID) {
+  return Diags.Report(FullSourceLoc(Loc, SourceMgr), DiagID);
+}
+
+/// \brief Retrieve the identifier table associated with the
+/// preprocessor.
+IdentifierTable &PCHReader::getIdentifierTable() {
+  assert(PP && "Forgot to set Preprocessor ?");
+  return PP->getIdentifierTable();
+}
+
+/// \brief Record that the given ID maps to the given switch-case
+/// statement.
+void PCHReader::RecordSwitchCaseID(SwitchCase *SC, unsigned ID) {
+  assert(SwitchCaseStmts[ID] == 0 && "Already have a SwitchCase with this ID");
+  SwitchCaseStmts[ID] = SC;
+}
+
+/// \brief Retrieve the switch-case statement with the given ID.
+SwitchCase *PCHReader::getSwitchCaseWithID(unsigned ID) {
+  assert(SwitchCaseStmts[ID] != 0 && "No SwitchCase with this ID");
+  return SwitchCaseStmts[ID];
+}
+
+/// \brief Record that the given label statement has been
+/// deserialized and has the given ID.
+void PCHReader::RecordLabelStmt(LabelStmt *S, unsigned ID) {
+  assert(LabelStmts.find(ID) == LabelStmts.end() &&
+         "Deserialized label twice");
+  LabelStmts[ID] = S;
+
+  // If we've already seen any goto statements that point to this
+  // label, resolve them now.
+  typedef std::multimap<unsigned, GotoStmt *>::iterator GotoIter;
+  std::pair<GotoIter, GotoIter> Gotos = UnresolvedGotoStmts.equal_range(ID);
+  for (GotoIter Goto = Gotos.first; Goto != Gotos.second; ++Goto)
+    Goto->second->setLabel(S);
+  UnresolvedGotoStmts.erase(Gotos.first, Gotos.second);
+
+  // If we've already seen any address-label statements that point to
+  // this label, resolve them now.
+  typedef std::multimap<unsigned, AddrLabelExpr *>::iterator AddrLabelIter;
+  std::pair<AddrLabelIter, AddrLabelIter> AddrLabels
+    = UnresolvedAddrLabelExprs.equal_range(ID);
+  for (AddrLabelIter AddrLabel = AddrLabels.first;
+       AddrLabel != AddrLabels.second; ++AddrLabel)
+    AddrLabel->second->setLabel(S);
+  UnresolvedAddrLabelExprs.erase(AddrLabels.first, AddrLabels.second);
+}
+
+/// \brief Set the label of the given statement to the label
+/// identified by ID.
+///
+/// Depending on the order in which the label and other statements
+/// referencing that label occur, this operation may complete
+/// immediately (updating the statement) or it may queue the
+/// statement to be back-patched later.
+void PCHReader::SetLabelOf(GotoStmt *S, unsigned ID) {
+  std::map<unsigned, LabelStmt *>::iterator Label = LabelStmts.find(ID);
+  if (Label != LabelStmts.end()) {
+    // We've already seen this label, so set the label of the goto and
+    // we're done.
+    S->setLabel(Label->second);
+  } else {
+    // We haven't seen this label yet, so add this goto to the set of
+    // unresolved goto statements.
+    UnresolvedGotoStmts.insert(std::make_pair(ID, S));
+  }
+}
+
+/// \brief Set the label of the given expression to the label
+/// identified by ID.
+///
+/// Depending on the order in which the label and other statements
+/// referencing that label occur, this operation may complete
+/// immediately (updating the statement) or it may queue the
+/// statement to be back-patched later.
+void PCHReader::SetLabelOf(AddrLabelExpr *S, unsigned ID) {
+  std::map<unsigned, LabelStmt *>::iterator Label = LabelStmts.find(ID);
+  if (Label != LabelStmts.end()) {
+    // We've already seen this label, so set the label of the
+    // label-address expression and we're done.
+    S->setLabel(Label->second);
+  } else {
+    // We haven't seen this label yet, so add this label-address
+    // expression to the set of unresolved label-address expressions.
+    UnresolvedAddrLabelExprs.insert(std::make_pair(ID, S));
+  }
+}
+
+
+PCHReader::LoadingTypeOrDecl::LoadingTypeOrDecl(PCHReader &Reader)
+  : Reader(Reader), Parent(Reader.CurrentlyLoadingTypeOrDecl) {
+  Reader.CurrentlyLoadingTypeOrDecl = this;
+}
+
+PCHReader::LoadingTypeOrDecl::~LoadingTypeOrDecl() {
+  if (!Parent) {
+    // If any identifiers with corresponding top-level declarations have
+    // been loaded, load those declarations now.
+    while (!Reader.PendingIdentifierInfos.empty()) {
+      Reader.SetGloballyVisibleDecls(Reader.PendingIdentifierInfos.front().II,
+                                 Reader.PendingIdentifierInfos.front().DeclIDs,
+                                     true);
+      Reader.PendingIdentifierInfos.pop_front();
+    }
+  }
+
+  Reader.CurrentlyLoadingTypeOrDecl = Parent;
+}