Merge branch 'master' of ssh://bitbucket.org/czan/honours

1 files changed, 1896 insertions, 0 deletions

diff --git a/clang/lib/Basic/SourceManager.cpp b/clang/lib/Basic/SourceManager.cpp
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+++ b/clang/lib/Basic/SourceManager.cpp
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+//===--- SourceManager.cpp - Track and cache source files -----------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+//  This file implements the SourceManager interface.
+//
+//===----------------------------------------------------------------------===//
+
+#include "clang/Basic/SourceManager.h"
+#include "clang/Basic/SourceManagerInternals.h"
+#include "clang/Basic/Diagnostic.h"
+#include "clang/Basic/FileManager.h"
+#include "llvm/ADT/StringSwitch.h"
+#include "llvm/ADT/Optional.h"
+#include "llvm/ADT/STLExtras.h"
+#include "llvm/Support/Compiler.h"
+#include "llvm/Support/MemoryBuffer.h"
+#include "llvm/Support/raw_ostream.h"
+#include "llvm/Support/Path.h"
+#include "llvm/Support/Capacity.h"
+#include <algorithm>
+#include <string>
+#include <cstring>
+#include <sys/stat.h>
+
+using namespace clang;
+using namespace SrcMgr;
+using llvm::MemoryBuffer;
+
+//===----------------------------------------------------------------------===//
+// SourceManager Helper Classes
+//===----------------------------------------------------------------------===//
+
+ContentCache::~ContentCache() {
+  if (shouldFreeBuffer())
+    delete Buffer.getPointer();
+}
+
+/// getSizeBytesMapped - Returns the number of bytes actually mapped for this
+/// ContentCache. This can be 0 if the MemBuffer was not actually expanded.
+unsigned ContentCache::getSizeBytesMapped() const {
+  return Buffer.getPointer() ? Buffer.getPointer()->getBufferSize() : 0;
+}
+
+/// Returns the kind of memory used to back the memory buffer for
+/// this content cache.  This is used for performance analysis.
+llvm::MemoryBuffer::BufferKind ContentCache::getMemoryBufferKind() const {
+  assert(Buffer.getPointer());
+
+  // Should be unreachable, but keep for sanity.
+  if (!Buffer.getPointer())
+    return llvm::MemoryBuffer::MemoryBuffer_Malloc;
+  
+  const llvm::MemoryBuffer *buf = Buffer.getPointer();
+  return buf->getBufferKind();
+}
+
+/// getSize - Returns the size of the content encapsulated by this ContentCache.
+///  This can be the size of the source file or the size of an arbitrary
+///  scratch buffer.  If the ContentCache encapsulates a source file, that
+///  file is not lazily brought in from disk to satisfy this query.
+unsigned ContentCache::getSize() const {
+  return Buffer.getPointer() ? (unsigned) Buffer.getPointer()->getBufferSize()
+                             : (unsigned) ContentsEntry->getSize();
+}
+
+void ContentCache::replaceBuffer(const llvm::MemoryBuffer *B,
+                                 bool DoNotFree) {
+  if (B == Buffer.getPointer()) {
+    assert(0 && "Replacing with the same buffer");
+    Buffer.setInt(DoNotFree? DoNotFreeFlag : 0);
+    return;
+  }
+  
+  if (shouldFreeBuffer())
+    delete Buffer.getPointer();
+  Buffer.setPointer(B);
+  Buffer.setInt(DoNotFree? DoNotFreeFlag : 0);
+}
+
+const llvm::MemoryBuffer *ContentCache::getBuffer(DiagnosticsEngine &Diag,
+                                                  const SourceManager &SM,
+                                                  SourceLocation Loc,
+                                                  bool *Invalid) const {
+  // Lazily create the Buffer for ContentCaches that wrap files.  If we already
+  // computed it, just return what we have.
+  if (Buffer.getPointer() || ContentsEntry == 0) {
+    if (Invalid)
+      *Invalid = isBufferInvalid();
+    
+    return Buffer.getPointer();
+  }    
+
+  std::string ErrorStr;
+  Buffer.setPointer(SM.getFileManager().getBufferForFile(ContentsEntry, &ErrorStr));
+
+  // If we were unable to open the file, then we are in an inconsistent
+  // situation where the content cache referenced a file which no longer
+  // exists. Most likely, we were using a stat cache with an invalid entry but
+  // the file could also have been removed during processing. Since we can't
+  // really deal with this situation, just create an empty buffer.
+  //
+  // FIXME: This is definitely not ideal, but our immediate clients can't
+  // currently handle returning a null entry here. Ideally we should detect
+  // that we are in an inconsistent situation and error out as quickly as
+  // possible.
+  if (!Buffer.getPointer()) {
+    const StringRef FillStr("<<<MISSING SOURCE FILE>>>\n");
+    Buffer.setPointer(MemoryBuffer::getNewMemBuffer(ContentsEntry->getSize(), 
+                                                    "<invalid>"));
+    char *Ptr = const_cast<char*>(Buffer.getPointer()->getBufferStart());
+    for (unsigned i = 0, e = ContentsEntry->getSize(); i != e; ++i)
+      Ptr[i] = FillStr[i % FillStr.size()];
+
+    if (Diag.isDiagnosticInFlight())
+      Diag.SetDelayedDiagnostic(diag::err_cannot_open_file, 
+                                ContentsEntry->getName(), ErrorStr);
+    else 
+      Diag.Report(Loc, diag::err_cannot_open_file)
+        << ContentsEntry->getName() << ErrorStr;
+
+    Buffer.setInt(Buffer.getInt() | InvalidFlag);
+    
+    if (Invalid) *Invalid = true;
+    return Buffer.getPointer();
+  }
+  
+  // Check that the file's size is the same as in the file entry (which may
+  // have come from a stat cache).
+  if (getRawBuffer()->getBufferSize() != (size_t)ContentsEntry->getSize()) {
+    if (Diag.isDiagnosticInFlight())
+      Diag.SetDelayedDiagnostic(diag::err_file_modified,
+                                ContentsEntry->getName());
+    else
+      Diag.Report(Loc, diag::err_file_modified)
+        << ContentsEntry->getName();
+
+    Buffer.setInt(Buffer.getInt() | InvalidFlag);
+    if (Invalid) *Invalid = true;
+    return Buffer.getPointer();
+  }
+
+  // If the buffer is valid, check to see if it has a UTF Byte Order Mark
+  // (BOM).  We only support UTF-8 with and without a BOM right now.  See
+  // http://en.wikipedia.org/wiki/Byte_order_mark for more information.
+  StringRef BufStr = Buffer.getPointer()->getBuffer();
+  const char *InvalidBOM = llvm::StringSwitch<const char *>(BufStr)
+    .StartsWith("\xFE\xFF", "UTF-16 (BE)")
+    .StartsWith("\xFF\xFE", "UTF-16 (LE)")
+    .StartsWith("\x00\x00\xFE\xFF", "UTF-32 (BE)")
+    .StartsWith("\xFF\xFE\x00\x00", "UTF-32 (LE)")
+    .StartsWith("\x2B\x2F\x76", "UTF-7")
+    .StartsWith("\xF7\x64\x4C", "UTF-1")
+    .StartsWith("\xDD\x73\x66\x73", "UTF-EBCDIC")
+    .StartsWith("\x0E\xFE\xFF", "SDSU")
+    .StartsWith("\xFB\xEE\x28", "BOCU-1")
+    .StartsWith("\x84\x31\x95\x33", "GB-18030")
+    .Default(0);
+
+  if (InvalidBOM) {
+    Diag.Report(Loc, diag::err_unsupported_bom)
+      << InvalidBOM << ContentsEntry->getName();
+    Buffer.setInt(Buffer.getInt() | InvalidFlag);
+  }
+  
+  if (Invalid)
+    *Invalid = isBufferInvalid();
+  
+  return Buffer.getPointer();
+}
+
+unsigned LineTableInfo::getLineTableFilenameID(StringRef Name) {
+  // Look up the filename in the string table, returning the pre-existing value
+  // if it exists.
+  llvm::StringMapEntry<unsigned> &Entry =
+    FilenameIDs.GetOrCreateValue(Name, ~0U);
+  if (Entry.getValue() != ~0U)
+    return Entry.getValue();
+
+  // Otherwise, assign this the next available ID.
+  Entry.setValue(FilenamesByID.size());
+  FilenamesByID.push_back(&Entry);
+  return FilenamesByID.size()-1;
+}
+
+/// AddLineNote - Add a line note to the line table that indicates that there
+/// is a #line at the specified FID/Offset location which changes the presumed
+/// location to LineNo/FilenameID.
+void LineTableInfo::AddLineNote(int FID, unsigned Offset,
+                                unsigned LineNo, int FilenameID) {
+  std::vector<LineEntry> &Entries = LineEntries[FID];
+
+  assert((Entries.empty() || Entries.back().FileOffset < Offset) &&
+         "Adding line entries out of order!");
+
+  SrcMgr::CharacteristicKind Kind = SrcMgr::C_User;
+  unsigned IncludeOffset = 0;
+
+  if (!Entries.empty()) {
+    // If this is a '#line 4' after '#line 42 "foo.h"', make sure to remember
+    // that we are still in "foo.h".
+    if (FilenameID == -1)
+      FilenameID = Entries.back().FilenameID;
+
+    // If we are after a line marker that switched us to system header mode, or
+    // that set #include information, preserve it.
+    Kind = Entries.back().FileKind;
+    IncludeOffset = Entries.back().IncludeOffset;
+  }
+
+  Entries.push_back(LineEntry::get(Offset, LineNo, FilenameID, Kind,
+                                   IncludeOffset));
+}
+
+/// AddLineNote This is the same as the previous version of AddLineNote, but is
+/// used for GNU line markers.  If EntryExit is 0, then this doesn't change the
+/// presumed #include stack.  If it is 1, this is a file entry, if it is 2 then
+/// this is a file exit.  FileKind specifies whether this is a system header or
+/// extern C system header.
+void LineTableInfo::AddLineNote(int FID, unsigned Offset,
+                                unsigned LineNo, int FilenameID,
+                                unsigned EntryExit,
+                                SrcMgr::CharacteristicKind FileKind) {
+  assert(FilenameID != -1 && "Unspecified filename should use other accessor");
+
+  std::vector<LineEntry> &Entries = LineEntries[FID];
+
+  assert((Entries.empty() || Entries.back().FileOffset < Offset) &&
+         "Adding line entries out of order!");
+
+  unsigned IncludeOffset = 0;
+  if (EntryExit == 0) {  // No #include stack change.
+    IncludeOffset = Entries.empty() ? 0 : Entries.back().IncludeOffset;
+  } else if (EntryExit == 1) {
+    IncludeOffset = Offset-1;
+  } else if (EntryExit == 2) {
+    assert(!Entries.empty() && Entries.back().IncludeOffset &&
+       "PPDirectives should have caught case when popping empty include stack");
+
+    // Get the include loc of the last entries' include loc as our include loc.
+    IncludeOffset = 0;
+    if (const LineEntry *PrevEntry =
+          FindNearestLineEntry(FID, Entries.back().IncludeOffset))
+      IncludeOffset = PrevEntry->IncludeOffset;
+  }
+
+  Entries.push_back(LineEntry::get(Offset, LineNo, FilenameID, FileKind,
+                                   IncludeOffset));
+}
+
+
+/// FindNearestLineEntry - Find the line entry nearest to FID that is before
+/// it.  If there is no line entry before Offset in FID, return null.
+const LineEntry *LineTableInfo::FindNearestLineEntry(int FID,
+                                                     unsigned Offset) {
+  const std::vector<LineEntry> &Entries = LineEntries[FID];
+  assert(!Entries.empty() && "No #line entries for this FID after all!");
+
+  // It is very common for the query to be after the last #line, check this
+  // first.
+  if (Entries.back().FileOffset <= Offset)
+    return &Entries.back();
+
+  // Do a binary search to find the maximal element that is still before Offset.
+  std::vector<LineEntry>::const_iterator I =
+    std::upper_bound(Entries.begin(), Entries.end(), Offset);
+  if (I == Entries.begin()) return 0;
+  return &*--I;
+}
+
+/// \brief Add a new line entry that has already been encoded into
+/// the internal representation of the line table.
+void LineTableInfo::AddEntry(int FID,
+                             const std::vector<LineEntry> &Entries) {
+  LineEntries[FID] = Entries;
+}
+
+/// getLineTableFilenameID - Return the uniqued ID for the specified filename.
+///
+unsigned SourceManager::getLineTableFilenameID(StringRef Name) {
+  if (LineTable == 0)
+    LineTable = new LineTableInfo();
+  return LineTable->getLineTableFilenameID(Name);
+}
+
+
+/// AddLineNote - Add a line note to the line table for the FileID and offset
+/// specified by Loc.  If FilenameID is -1, it is considered to be
+/// unspecified.
+void SourceManager::AddLineNote(SourceLocation Loc, unsigned LineNo,
+                                int FilenameID) {
+  std::pair<FileID, unsigned> LocInfo = getDecomposedExpansionLoc(Loc);
+
+  bool Invalid = false;
+  const SLocEntry &Entry = getSLocEntry(LocInfo.first, &Invalid);
+  if (!Entry.isFile() || Invalid)
+    return;
+  
+  const SrcMgr::FileInfo &FileInfo = Entry.getFile();
+
+  // Remember that this file has #line directives now if it doesn't already.
+  const_cast<SrcMgr::FileInfo&>(FileInfo).setHasLineDirectives();
+
+  if (LineTable == 0)
+    LineTable = new LineTableInfo();
+  LineTable->AddLineNote(LocInfo.first.ID, LocInfo.second, LineNo, FilenameID);
+}
+
+/// AddLineNote - Add a GNU line marker to the line table.
+void SourceManager::AddLineNote(SourceLocation Loc, unsigned LineNo,
+                                int FilenameID, bool IsFileEntry,
+                                bool IsFileExit, bool IsSystemHeader,
+                                bool IsExternCHeader) {
+  // If there is no filename and no flags, this is treated just like a #line,
+  // which does not change the flags of the previous line marker.
+  if (FilenameID == -1) {
+    assert(!IsFileEntry && !IsFileExit && !IsSystemHeader && !IsExternCHeader &&
+           "Can't set flags without setting the filename!");
+    return AddLineNote(Loc, LineNo, FilenameID);
+  }
+
+  std::pair<FileID, unsigned> LocInfo = getDecomposedExpansionLoc(Loc);
+
+  bool Invalid = false;
+  const SLocEntry &Entry = getSLocEntry(LocInfo.first, &Invalid);
+  if (!Entry.isFile() || Invalid)
+    return;
+  
+  const SrcMgr::FileInfo &FileInfo = Entry.getFile();
+
+  // Remember that this file has #line directives now if it doesn't already.
+  const_cast<SrcMgr::FileInfo&>(FileInfo).setHasLineDirectives();
+
+  if (LineTable == 0)
+    LineTable = new LineTableInfo();
+
+  SrcMgr::CharacteristicKind FileKind;
+  if (IsExternCHeader)
+    FileKind = SrcMgr::C_ExternCSystem;
+  else if (IsSystemHeader)
+    FileKind = SrcMgr::C_System;
+  else
+    FileKind = SrcMgr::C_User;
+
+  unsigned EntryExit = 0;
+  if (IsFileEntry)
+    EntryExit = 1;
+  else if (IsFileExit)
+    EntryExit = 2;
+
+  LineTable->AddLineNote(LocInfo.first.ID, LocInfo.second, LineNo, FilenameID,
+                         EntryExit, FileKind);
+}
+
+LineTableInfo &SourceManager::getLineTable() {
+  if (LineTable == 0)
+    LineTable = new LineTableInfo();
+  return *LineTable;
+}
+
+//===----------------------------------------------------------------------===//
+// Private 'Create' methods.
+//===----------------------------------------------------------------------===//
+
+SourceManager::SourceManager(DiagnosticsEngine &Diag, FileManager &FileMgr)
+  : Diag(Diag), FileMgr(FileMgr), OverridenFilesKeepOriginalName(true),
+    ExternalSLocEntries(0), LineTable(0), NumLinearScans(0),
+    NumBinaryProbes(0), FakeBufferForRecovery(0),
+    FakeContentCacheForRecovery(0) {
+  clearIDTables();
+  Diag.setSourceManager(this);
+}
+
+SourceManager::~SourceManager() {
+  delete LineTable;
+
+  // Delete FileEntry objects corresponding to content caches.  Since the actual
+  // content cache objects are bump pointer allocated, we just have to run the
+  // dtors, but we call the deallocate method for completeness.
+  for (unsigned i = 0, e = MemBufferInfos.size(); i != e; ++i) {
+    if (MemBufferInfos[i]) {
+      MemBufferInfos[i]->~ContentCache();
+      ContentCacheAlloc.Deallocate(MemBufferInfos[i]);
+    }
+  }
+  for (llvm::DenseMap<const FileEntry*, SrcMgr::ContentCache*>::iterator
+       I = FileInfos.begin(), E = FileInfos.end(); I != E; ++I) {
+    if (I->second) {
+      I->second->~ContentCache();
+      ContentCacheAlloc.Deallocate(I->second);
+    }
+  }
+  
+  delete FakeBufferForRecovery;
+  delete FakeContentCacheForRecovery;
+
+  for (llvm::DenseMap<FileID, MacroArgsMap *>::iterator
+         I = MacroArgsCacheMap.begin(),E = MacroArgsCacheMap.end(); I!=E; ++I) {
+    delete I->second;
+  }
+}
+
+void SourceManager::clearIDTables() {
+  MainFileID = FileID();
+  LocalSLocEntryTable.clear();
+  LoadedSLocEntryTable.clear();
+  SLocEntryLoaded.clear();
+  LastLineNoFileIDQuery = FileID();
+  LastLineNoContentCache = 0;
+  LastFileIDLookup = FileID();
+
+  if (LineTable)
+    LineTable->clear();
+
+  // Use up FileID #0 as an invalid expansion.
+  NextLocalOffset = 0;
+  CurrentLoadedOffset = MaxLoadedOffset;
+  createExpansionLoc(SourceLocation(),SourceLocation(),SourceLocation(), 1);
+}
+
+/// getOrCreateContentCache - Create or return a cached ContentCache for the
+/// specified file.
+const ContentCache *
+SourceManager::getOrCreateContentCache(const FileEntry *FileEnt) {
+  assert(FileEnt && "Didn't specify a file entry to use?");
+
+  // Do we already have information about this file?
+  ContentCache *&Entry = FileInfos[FileEnt];
+  if (Entry) return Entry;
+
+  // Nope, create a new Cache entry.  Make sure it is at least 8-byte aligned
+  // so that FileInfo can use the low 3 bits of the pointer for its own
+  // nefarious purposes.
+  unsigned EntryAlign = llvm::AlignOf<ContentCache>::Alignment;
+  EntryAlign = std::max(8U, EntryAlign);
+  Entry = ContentCacheAlloc.Allocate<ContentCache>(1, EntryAlign);
+
+  // If the file contents are overridden with contents from another file,
+  // pass that file to ContentCache.
+  llvm::DenseMap<const FileEntry *, const FileEntry *>::iterator
+      overI = OverriddenFiles.find(FileEnt);
+  if (overI == OverriddenFiles.end())
+    new (Entry) ContentCache(FileEnt);
+  else
+    new (Entry) ContentCache(OverridenFilesKeepOriginalName ? FileEnt
+                                                            : overI->second,
+                             overI->second);
+
+  return Entry;
+}
+
+
+/// createMemBufferContentCache - Create a new ContentCache for the specified
+///  memory buffer.  This does no caching.
+const ContentCache*
+SourceManager::createMemBufferContentCache(const MemoryBuffer *Buffer) {
+  // Add a new ContentCache to the MemBufferInfos list and return it.  Make sure
+  // it is at least 8-byte aligned so that FileInfo can use the low 3 bits of
+  // the pointer for its own nefarious purposes.
+  unsigned EntryAlign = llvm::AlignOf<ContentCache>::Alignment;
+  EntryAlign = std::max(8U, EntryAlign);
+  ContentCache *Entry = ContentCacheAlloc.Allocate<ContentCache>(1, EntryAlign);
+  new (Entry) ContentCache();
+  MemBufferInfos.push_back(Entry);
+  Entry->setBuffer(Buffer);
+  return Entry;
+}
+
+const SrcMgr::SLocEntry &SourceManager::loadSLocEntry(unsigned Index,
+                                                      bool *Invalid) const {
+  assert(!SLocEntryLoaded[Index]);
+  if (ExternalSLocEntries->ReadSLocEntry(-(static_cast<int>(Index) + 2))) {
+    if (Invalid)
+      *Invalid = true;
+    // If the file of the SLocEntry changed we could still have loaded it.
+    if (!SLocEntryLoaded[Index]) {
+      // Try to recover; create a SLocEntry so the rest of clang can handle it.
+      LoadedSLocEntryTable[Index] = SLocEntry::get(0,
+                                 FileInfo::get(SourceLocation(),
+                                               getFakeContentCacheForRecovery(),
+                                               SrcMgr::C_User));
+    }
+  }
+
+  return LoadedSLocEntryTable[Index];
+}
+
+std::pair<int, unsigned>
+SourceManager::AllocateLoadedSLocEntries(unsigned NumSLocEntries,
+                                         unsigned TotalSize) {
+  assert(ExternalSLocEntries && "Don't have an external sloc source");
+  LoadedSLocEntryTable.resize(LoadedSLocEntryTable.size() + NumSLocEntries);
+  SLocEntryLoaded.resize(LoadedSLocEntryTable.size());
+  CurrentLoadedOffset -= TotalSize;
+  assert(CurrentLoadedOffset >= NextLocalOffset && "Out of source locations");
+  int ID = LoadedSLocEntryTable.size();
+  return std::make_pair(-ID - 1, CurrentLoadedOffset);
+}
+
+/// \brief As part of recovering from missing or changed content, produce a
+/// fake, non-empty buffer.
+const llvm::MemoryBuffer *SourceManager::getFakeBufferForRecovery() const {
+  if (!FakeBufferForRecovery)
+    FakeBufferForRecovery
+      = llvm::MemoryBuffer::getMemBuffer("<<<INVALID BUFFER>>");
+  
+  return FakeBufferForRecovery;
+}
+
+/// \brief As part of recovering from missing or changed content, produce a
+/// fake content cache.
+const SrcMgr::ContentCache *
+SourceManager::getFakeContentCacheForRecovery() const {
+  if (!FakeContentCacheForRecovery) {
+    FakeContentCacheForRecovery = new ContentCache();
+    FakeContentCacheForRecovery->replaceBuffer(getFakeBufferForRecovery(),
+                                               /*DoNotFree=*/true);
+  }
+  return FakeContentCacheForRecovery;
+}
+
+//===----------------------------------------------------------------------===//
+// Methods to create new FileID's and macro expansions.
+//===----------------------------------------------------------------------===//
+
+/// createFileID - Create a new FileID for the specified ContentCache and
+/// include position.  This works regardless of whether the ContentCache
+/// corresponds to a file or some other input source.
+FileID SourceManager::createFileID(const ContentCache *File,
+                                   SourceLocation IncludePos,
+                                   SrcMgr::CharacteristicKind FileCharacter,
+                                   int LoadedID, unsigned LoadedOffset) {
+  if (LoadedID < 0) {
+    assert(LoadedID != -1 && "Loading sentinel FileID");
+    unsigned Index = unsigned(-LoadedID) - 2;
+    assert(Index < LoadedSLocEntryTable.size() && "FileID out of range");
+    assert(!SLocEntryLoaded[Index] && "FileID already loaded");
+    LoadedSLocEntryTable[Index] = SLocEntry::get(LoadedOffset,
+        FileInfo::get(IncludePos, File, FileCharacter));
+    SLocEntryLoaded[Index] = true;
+    return FileID::get(LoadedID);
+  }
+  LocalSLocEntryTable.push_back(SLocEntry::get(NextLocalOffset,
+                                               FileInfo::get(IncludePos, File,
+                                                             FileCharacter)));
+  unsigned FileSize = File->getSize();
+  assert(NextLocalOffset + FileSize + 1 > NextLocalOffset &&
+         NextLocalOffset + FileSize + 1 <= CurrentLoadedOffset &&
+         "Ran out of source locations!");
+  // We do a +1 here because we want a SourceLocation that means "the end of the
+  // file", e.g. for the "no newline at the end of the file" diagnostic.
+  NextLocalOffset += FileSize + 1;
+
+  // Set LastFileIDLookup to the newly created file.  The next getFileID call is
+  // almost guaranteed to be from that file.
+  FileID FID = FileID::get(LocalSLocEntryTable.size()-1);
+  return LastFileIDLookup = FID;
+}
+
+SourceLocation
+SourceManager::createMacroArgExpansionLoc(SourceLocation SpellingLoc,
+                                          SourceLocation ExpansionLoc,
+                                          unsigned TokLength) {
+  ExpansionInfo Info = ExpansionInfo::createForMacroArg(SpellingLoc,
+                                                        ExpansionLoc);
+  return createExpansionLocImpl(Info, TokLength);
+}
+
+SourceLocation
+SourceManager::createExpansionLoc(SourceLocation SpellingLoc,
+                                  SourceLocation ExpansionLocStart,
+                                  SourceLocation ExpansionLocEnd,
+                                  unsigned TokLength,
+                                  int LoadedID,
+                                  unsigned LoadedOffset) {
+  ExpansionInfo Info = ExpansionInfo::create(SpellingLoc, ExpansionLocStart,
+                                             ExpansionLocEnd);
+  return createExpansionLocImpl(Info, TokLength, LoadedID, LoadedOffset);
+}
+
+SourceLocation
+SourceManager::createExpansionLocImpl(const ExpansionInfo &Info,
+                                      unsigned TokLength,
+                                      int LoadedID,
+                                      unsigned LoadedOffset) {
+  if (LoadedID < 0) {
+    assert(LoadedID != -1 && "Loading sentinel FileID");
+    unsigned Index = unsigned(-LoadedID) - 2;
+    assert(Index < LoadedSLocEntryTable.size() && "FileID out of range");
+    assert(!SLocEntryLoaded[Index] && "FileID already loaded");
+    LoadedSLocEntryTable[Index] = SLocEntry::get(LoadedOffset, Info);
+    SLocEntryLoaded[Index] = true;
+    return SourceLocation::getMacroLoc(LoadedOffset);
+  }
+  LocalSLocEntryTable.push_back(SLocEntry::get(NextLocalOffset, Info));
+  assert(NextLocalOffset + TokLength + 1 > NextLocalOffset &&
+         NextLocalOffset + TokLength + 1 <= CurrentLoadedOffset &&
+         "Ran out of source locations!");
+  // See createFileID for that +1.
+  NextLocalOffset += TokLength + 1;
+  return SourceLocation::getMacroLoc(NextLocalOffset - (TokLength + 1));
+}
+
+const llvm::MemoryBuffer *
+SourceManager::getMemoryBufferForFile(const FileEntry *File,
+                                      bool *Invalid) {
+  const SrcMgr::ContentCache *IR = getOrCreateContentCache(File);
+  assert(IR && "getOrCreateContentCache() cannot return NULL");
+  return IR->getBuffer(Diag, *this, SourceLocation(), Invalid);
+}
+
+void SourceManager::overrideFileContents(const FileEntry *SourceFile,
+                                         const llvm::MemoryBuffer *Buffer,
+                                         bool DoNotFree) {
+  const SrcMgr::ContentCache *IR = getOrCreateContentCache(SourceFile);
+  assert(IR && "getOrCreateContentCache() cannot return NULL");
+
+  const_cast<SrcMgr::ContentCache *>(IR)->replaceBuffer(Buffer, DoNotFree);
+  const_cast<SrcMgr::ContentCache *>(IR)->BufferOverridden = true;
+}
+
+void SourceManager::overrideFileContents(const FileEntry *SourceFile,
+                                         const FileEntry *NewFile) {
+  assert(SourceFile->getSize() == NewFile->getSize() &&
+         "Different sizes, use the FileManager to create a virtual file with "
+         "the correct size");
+  assert(FileInfos.count(SourceFile) == 0 &&
+         "This function should be called at the initialization stage, before "
+         "any parsing occurs.");
+  OverriddenFiles[SourceFile] = NewFile;
+}
+
+StringRef SourceManager::getBufferData(FileID FID, bool *Invalid) const {
+  bool MyInvalid = false;
+  const SLocEntry &SLoc = getSLocEntry(FID, &MyInvalid);
+  if (!SLoc.isFile() || MyInvalid) {
+    if (Invalid) 
+      *Invalid = true;
+    return "<<<<<INVALID SOURCE LOCATION>>>>>";
+  }
+  
+  const llvm::MemoryBuffer *Buf
+    = SLoc.getFile().getContentCache()->getBuffer(Diag, *this, SourceLocation(), 
+                                                  &MyInvalid);
+  if (Invalid)
+    *Invalid = MyInvalid;
+
+  if (MyInvalid)
+    return "<<<<<INVALID SOURCE LOCATION>>>>>";
+  
+  return Buf->getBuffer();
+}
+
+//===----------------------------------------------------------------------===//
+// SourceLocation manipulation methods.
+//===----------------------------------------------------------------------===//
+
+/// \brief Return the FileID for a SourceLocation.
+///
+/// This is the cache-miss path of getFileID. Not as hot as that function, but
+/// still very important. It is responsible for finding the entry in the
+/// SLocEntry tables that contains the specified location.
+FileID SourceManager::getFileIDSlow(unsigned SLocOffset) const {
+  if (!SLocOffset)
+    return FileID::get(0);
+
+  // Now it is time to search for the correct file. See where the SLocOffset
+  // sits in the global view and consult local or loaded buffers for it.
+  if (SLocOffset < NextLocalOffset)
+    return getFileIDLocal(SLocOffset);
+  return getFileIDLoaded(SLocOffset);
+}
+
+/// \brief Return the FileID for a SourceLocation with a low offset.
+///
+/// This function knows that the SourceLocation is in a local buffer, not a
+/// loaded one.
+FileID SourceManager::getFileIDLocal(unsigned SLocOffset) const {
+  assert(SLocOffset < NextLocalOffset && "Bad function choice");
+
+  // After the first and second level caches, I see two common sorts of
+  // behavior: 1) a lot of searched FileID's are "near" the cached file
+  // location or are "near" the cached expansion location. 2) others are just
+  // completely random and may be a very long way away.
+  //
+  // To handle this, we do a linear search for up to 8 steps to catch #1 quickly
+  // then we fall back to a less cache efficient, but more scalable, binary
+  // search to find the location.
+
+  // See if this is near the file point - worst case we start scanning from the
+  // most newly created FileID.
+  std::vector<SrcMgr::SLocEntry>::const_iterator I;
+
+  if (LastFileIDLookup.ID < 0 ||
+      LocalSLocEntryTable[LastFileIDLookup.ID].getOffset() < SLocOffset) {
+    // Neither loc prunes our search.
+    I = LocalSLocEntryTable.end();
+  } else {
+    // Perhaps it is near the file point.
+    I = LocalSLocEntryTable.begin()+LastFileIDLookup.ID;
+  }
+
+  // Find the FileID that contains this.  "I" is an iterator that points to a
+  // FileID whose offset is known to be larger than SLocOffset.
+  unsigned NumProbes = 0;
+  while (1) {
+    --I;
+    if (I->getOffset() <= SLocOffset) {
+      FileID Res = FileID::get(int(I - LocalSLocEntryTable.begin()));
+
+      // If this isn't an expansion, remember it.  We have good locality across
+      // FileID lookups.
+      if (!I->isExpansion())
+        LastFileIDLookup = Res;
+      NumLinearScans += NumProbes+1;
+      return Res;
+    }
+    if (++NumProbes == 8)
+      break;
+  }
+
+  // Convert "I" back into an index.  We know that it is an entry whose index is
+  // larger than the offset we are looking for.
+  unsigned GreaterIndex = I - LocalSLocEntryTable.begin();
+  // LessIndex - This is the lower bound of the range that we're searching.
+  // We know that the offset corresponding to the FileID is is less than
+  // SLocOffset.
+  unsigned LessIndex = 0;
+  NumProbes = 0;
+  while (1) {
+    bool Invalid = false;
+    unsigned MiddleIndex = (GreaterIndex-LessIndex)/2+LessIndex;
+    unsigned MidOffset = getLocalSLocEntry(MiddleIndex, &Invalid).getOffset();
+    if (Invalid)
+      return FileID::get(0);
+    
+    ++NumProbes;
+
+    // If the offset of the midpoint is too large, chop the high side of the
+    // range to the midpoint.
+    if (MidOffset > SLocOffset) {
+      GreaterIndex = MiddleIndex;
+      continue;
+    }
+
+    // If the middle index contains the value, succeed and return.
+    // FIXME: This could be made faster by using a function that's aware of
+    // being in the local area.
+    if (isOffsetInFileID(FileID::get(MiddleIndex), SLocOffset)) {
+      FileID Res = FileID::get(MiddleIndex);
+
+      // If this isn't a macro expansion, remember it.  We have good locality
+      // across FileID lookups.
+      if (!LocalSLocEntryTable[MiddleIndex].isExpansion())
+        LastFileIDLookup = Res;
+      NumBinaryProbes += NumProbes;
+      return Res;
+    }
+
+    // Otherwise, move the low-side up to the middle index.
+    LessIndex = MiddleIndex;
+  }
+}
+
+/// \brief Return the FileID for a SourceLocation with a high offset.
+///
+/// This function knows that the SourceLocation is in a loaded buffer, not a
+/// local one.
+FileID SourceManager::getFileIDLoaded(unsigned SLocOffset) const {
+  // Sanity checking, otherwise a bug may lead to hanging in release build.
+  if (SLocOffset < CurrentLoadedOffset) {
+    assert(0 && "Invalid SLocOffset or bad function choice");
+    return FileID();
+  }
+
+  // Essentially the same as the local case, but the loaded array is sorted
+  // in the other direction.
+
+  // First do a linear scan from the last lookup position, if possible.
+  unsigned I;
+  int LastID = LastFileIDLookup.ID;
+  if (LastID >= 0 || getLoadedSLocEntryByID(LastID).getOffset() < SLocOffset)
+    I = 0;
+  else
+    I = (-LastID - 2) + 1;
+
+  unsigned NumProbes;
+  for (NumProbes = 0; NumProbes < 8; ++NumProbes, ++I) {
+    // Make sure the entry is loaded!
+    const SrcMgr::SLocEntry &E = getLoadedSLocEntry(I);
+    if (E.getOffset() <= SLocOffset) {
+      FileID Res = FileID::get(-int(I) - 2);
+
+      if (!E.isExpansion())
+        LastFileIDLookup = Res;
+      NumLinearScans += NumProbes + 1;
+      return Res;
+    }
+  }
+
+  // Linear scan failed. Do the binary search. Note the reverse sorting of the
+  // table: GreaterIndex is the one where the offset is greater, which is
+  // actually a lower index!
+  unsigned GreaterIndex = I;
+  unsigned LessIndex = LoadedSLocEntryTable.size();
+  NumProbes = 0;
+  while (1) {
+    ++NumProbes;
+    unsigned MiddleIndex = (LessIndex - GreaterIndex) / 2 + GreaterIndex;
+    const SrcMgr::SLocEntry &E = getLoadedSLocEntry(MiddleIndex);
+
+    ++NumProbes;
+
+    if (E.getOffset() > SLocOffset) {
+      GreaterIndex = MiddleIndex;
+      continue;
+    }
+
+    if (isOffsetInFileID(FileID::get(-int(MiddleIndex) - 2), SLocOffset)) {
+      FileID Res = FileID::get(-int(MiddleIndex) - 2);
+      if (!E.isExpansion())
+        LastFileIDLookup = Res;
+      NumBinaryProbes += NumProbes;
+      return Res;
+    }
+
+    LessIndex = MiddleIndex;
+  }
+}
+
+SourceLocation SourceManager::
+getExpansionLocSlowCase(SourceLocation Loc) const {
+  do {
+    // Note: If Loc indicates an offset into a token that came from a macro
+    // expansion (e.g. the 5th character of the token) we do not want to add
+    // this offset when going to the expansion location.  The expansion
+    // location is the macro invocation, which the offset has nothing to do
+    // with.  This is unlike when we get the spelling loc, because the offset
+    // directly correspond to the token whose spelling we're inspecting.
+    Loc = getSLocEntry(getFileID(Loc)).getExpansion().getExpansionLocStart();
+  } while (!Loc.isFileID());
+
+  return Loc;
+}
+
+SourceLocation SourceManager::getSpellingLocSlowCase(SourceLocation Loc) const {
+  do {
+    std::pair<FileID, unsigned> LocInfo = getDecomposedLoc(Loc);
+    Loc = getSLocEntry(LocInfo.first).getExpansion().getSpellingLoc();
+    Loc = Loc.getLocWithOffset(LocInfo.second);
+  } while (!Loc.isFileID());
+  return Loc;
+}
+
+SourceLocation SourceManager::getFileLocSlowCase(SourceLocation Loc) const {
+  do {
+    if (isMacroArgExpansion(Loc))
+      Loc = getImmediateSpellingLoc(Loc);
+    else
+      Loc = getImmediateExpansionRange(Loc).first;
+  } while (!Loc.isFileID());
+  return Loc;
+}
+
+
+std::pair<FileID, unsigned>
+SourceManager::getDecomposedExpansionLocSlowCase(
+                                             const SrcMgr::SLocEntry *E) const {
+  // If this is an expansion record, walk through all the expansion points.
+  FileID FID;
+  SourceLocation Loc;
+  unsigned Offset;
+  do {
+    Loc = E->getExpansion().getExpansionLocStart();
+
+    FID = getFileID(Loc);
+    E = &getSLocEntry(FID);
+    Offset = Loc.getOffset()-E->getOffset();
+  } while (!Loc.isFileID());
+
+  return std::make_pair(FID, Offset);
+}
+
+std::pair<FileID, unsigned>
+SourceManager::getDecomposedSpellingLocSlowCase(const SrcMgr::SLocEntry *E,
+                                                unsigned Offset) const {
+  // If this is an expansion record, walk through all the expansion points.
+  FileID FID;
+  SourceLocation Loc;
+  do {
+    Loc = E->getExpansion().getSpellingLoc();
+    Loc = Loc.getLocWithOffset(Offset);
+
+    FID = getFileID(Loc);
+    E = &getSLocEntry(FID);
+    Offset = Loc.getOffset()-E->getOffset();
+  } while (!Loc.isFileID());
+
+  return std::make_pair(FID, Offset);
+}
+
+/// getImmediateSpellingLoc - Given a SourceLocation object, return the
+/// spelling location referenced by the ID.  This is the first level down
+/// towards the place where the characters that make up the lexed token can be
+/// found.  This should not generally be used by clients.
+SourceLocation SourceManager::getImmediateSpellingLoc(SourceLocation Loc) const{
+  if (Loc.isFileID()) return Loc;
+  std::pair<FileID, unsigned> LocInfo = getDecomposedLoc(Loc);
+  Loc = getSLocEntry(LocInfo.first).getExpansion().getSpellingLoc();
+  return Loc.getLocWithOffset(LocInfo.second);
+}
+
+
+/// getImmediateExpansionRange - Loc is required to be an expansion location.
+/// Return the start/end of the expansion information.
+std::pair<SourceLocation,SourceLocation>
+SourceManager::getImmediateExpansionRange(SourceLocation Loc) const {
+  assert(Loc.isMacroID() && "Not a macro expansion loc!");
+  const ExpansionInfo &Expansion = getSLocEntry(getFileID(Loc)).getExpansion();
+  return Expansion.getExpansionLocRange();
+}
+
+/// getExpansionRange - Given a SourceLocation object, return the range of
+/// tokens covered by the expansion in the ultimate file.
+std::pair<SourceLocation,SourceLocation>
+SourceManager::getExpansionRange(SourceLocation Loc) const {
+  if (Loc.isFileID()) return std::make_pair(Loc, Loc);
+
+  std::pair<SourceLocation,SourceLocation> Res =
+    getImmediateExpansionRange(Loc);
+
+  // Fully resolve the start and end locations to their ultimate expansion
+  // points.
+  while (!Res.first.isFileID())
+    Res.first = getImmediateExpansionRange(Res.first).first;
+  while (!Res.second.isFileID())
+    Res.second = getImmediateExpansionRange(Res.second).second;
+  return Res;
+}
+
+bool SourceManager::isMacroArgExpansion(SourceLocation Loc) const {
+  if (!Loc.isMacroID()) return false;
+
+  FileID FID = getFileID(Loc);
+  const SrcMgr::SLocEntry *E = &getSLocEntry(FID);
+  const SrcMgr::ExpansionInfo &Expansion = E->getExpansion();
+  return Expansion.isMacroArgExpansion();
+}
+
+
+//===----------------------------------------------------------------------===//
+// Queries about the code at a SourceLocation.
+//===----------------------------------------------------------------------===//
+
+/// getCharacterData - Return a pointer to the start of the specified location
+/// in the appropriate MemoryBuffer.
+const char *SourceManager::getCharacterData(SourceLocation SL,
+                                            bool *Invalid) const {
+  // Note that this is a hot function in the getSpelling() path, which is
+  // heavily used by -E mode.
+  std::pair<FileID, unsigned> LocInfo = getDecomposedSpellingLoc(SL);
+
+  // Note that calling 'getBuffer()' may lazily page in a source file.
+  bool CharDataInvalid = false;
+  const SLocEntry &Entry = getSLocEntry(LocInfo.first, &CharDataInvalid);
+  if (CharDataInvalid || !Entry.isFile()) {
+    if (Invalid)
+      *Invalid = true;
+    
+    return "<<<<INVALID BUFFER>>>>";
+  }
+  const llvm::MemoryBuffer *Buffer
+    = Entry.getFile().getContentCache()
+                  ->getBuffer(Diag, *this, SourceLocation(), &CharDataInvalid);
+  if (Invalid)
+    *Invalid = CharDataInvalid;
+  return Buffer->getBufferStart() + (CharDataInvalid? 0 : LocInfo.second);
+}
+
+
+/// getColumnNumber - Return the column # for the specified file position.
+/// this is significantly cheaper to compute than the line number.
+unsigned SourceManager::getColumnNumber(FileID FID, unsigned FilePos,
+                                        bool *Invalid) const {
+  bool MyInvalid = false;
+  const llvm::MemoryBuffer *MemBuf = getBuffer(FID, &MyInvalid);
+  if (Invalid)
+    *Invalid = MyInvalid;
+
+  if (MyInvalid)
+    return 1;
+
+  if (FilePos >= MemBuf->getBufferSize()) {
+    if (Invalid)
+      *Invalid = MyInvalid;
+    return 1;
+  }
+
+  const char *Buf = MemBuf->getBufferStart();
+  unsigned LineStart = FilePos;
+  while (LineStart && Buf[LineStart-1] != '\n' && Buf[LineStart-1] != '\r')
+    --LineStart;
+  return FilePos-LineStart+1;
+}
+
+// isInvalid - Return the result of calling loc.isInvalid(), and
+// if Invalid is not null, set its value to same.
+static bool isInvalid(SourceLocation Loc, bool *Invalid) {
+  bool MyInvalid = Loc.isInvalid();
+  if (Invalid)
+    *Invalid = MyInvalid;
+  return MyInvalid;
+}
+
+unsigned SourceManager::getSpellingColumnNumber(SourceLocation Loc,
+                                                bool *Invalid) const {
+  if (isInvalid(Loc, Invalid)) return 0;
+  std::pair<FileID, unsigned> LocInfo = getDecomposedSpellingLoc(Loc);
+  return getColumnNumber(LocInfo.first, LocInfo.second, Invalid);
+}
+
+unsigned SourceManager::getExpansionColumnNumber(SourceLocation Loc,
+                                                 bool *Invalid) const {
+  if (isInvalid(Loc, Invalid)) return 0;
+  std::pair<FileID, unsigned> LocInfo = getDecomposedExpansionLoc(Loc);
+  return getColumnNumber(LocInfo.first, LocInfo.second, Invalid);
+}
+
+unsigned SourceManager::getPresumedColumnNumber(SourceLocation Loc,
+                                                bool *Invalid) const {
+  if (isInvalid(Loc, Invalid)) return 0;
+  return getPresumedLoc(Loc).getColumn();
+}
+
+#ifdef __SSE2__
+#include <emmintrin.h>
+#endif
+
+static LLVM_ATTRIBUTE_NOINLINE void
+ComputeLineNumbers(DiagnosticsEngine &Diag, ContentCache *FI,
+                   llvm::BumpPtrAllocator &Alloc,
+                   const SourceManager &SM, bool &Invalid);
+static void ComputeLineNumbers(DiagnosticsEngine &Diag, ContentCache *FI,
+                               llvm::BumpPtrAllocator &Alloc,
+                               const SourceManager &SM, bool &Invalid) {
+  // Note that calling 'getBuffer()' may lazily page in the file.
+  const MemoryBuffer *Buffer = FI->getBuffer(Diag, SM, SourceLocation(),
+                                             &Invalid);
+  if (Invalid)
+    return;
+
+  // Find the file offsets of all of the *physical* source lines.  This does
+  // not look at trigraphs, escaped newlines, or anything else tricky.
+  SmallVector<unsigned, 256> LineOffsets;
+
+  // Line #1 starts at char 0.
+  LineOffsets.push_back(0);
+
+  const unsigned char *Buf = (const unsigned char *)Buffer->getBufferStart();
+  const unsigned char *End = (const unsigned char *)Buffer->getBufferEnd();
+  unsigned Offs = 0;
+  while (1) {
+    // Skip over the contents of the line.
+    const unsigned char *NextBuf = (const unsigned char *)Buf;
+
+#ifdef __SSE2__
+    // Try to skip to the next newline using SSE instructions. This is very
+    // performance sensitive for programs with lots of diagnostics and in -E
+    // mode.
+    __m128i CRs = _mm_set1_epi8('\r');
+    __m128i LFs = _mm_set1_epi8('\n');
+
+    // First fix up the alignment to 16 bytes.
+    while (((uintptr_t)NextBuf & 0xF) != 0) {
+      if (*NextBuf == '\n' || *NextBuf == '\r' || *NextBuf == '\0')
+        goto FoundSpecialChar;
+      ++NextBuf;
+    }
+
+    // Scan 16 byte chunks for '\r' and '\n'. Ignore '\0'.
+    while (NextBuf+16 <= End) {
+      __m128i Chunk = *(__m128i*)NextBuf;
+      __m128i Cmp = _mm_or_si128(_mm_cmpeq_epi8(Chunk, CRs),
+                                 _mm_cmpeq_epi8(Chunk, LFs));
+      unsigned Mask = _mm_movemask_epi8(Cmp);
+
+      // If we found a newline, adjust the pointer and jump to the handling code.
+      if (Mask != 0) {
+        NextBuf += llvm::CountTrailingZeros_32(Mask);
+        goto FoundSpecialChar;
+      }
+      NextBuf += 16;
+    }
+#endif
+
+    while (*NextBuf != '\n' && *NextBuf != '\r' && *NextBuf != '\0')
+      ++NextBuf;
+
+#ifdef __SSE2__
+FoundSpecialChar:
+#endif
+    Offs += NextBuf-Buf;
+    Buf = NextBuf;
+
+    if (Buf[0] == '\n' || Buf[0] == '\r') {
+      // If this is \n\r or \r\n, skip both characters.
+      if ((Buf[1] == '\n' || Buf[1] == '\r') && Buf[0] != Buf[1])
+        ++Offs, ++Buf;
+      ++Offs, ++Buf;
+      LineOffsets.push_back(Offs);
+    } else {
+      // Otherwise, this is a null.  If end of file, exit.
+      if (Buf == End) break;
+      // Otherwise, skip the null.
+      ++Offs, ++Buf;
+    }
+  }
+
+  // Copy the offsets into the FileInfo structure.
+  FI->NumLines = LineOffsets.size();
+  FI->SourceLineCache = Alloc.Allocate<unsigned>(LineOffsets.size());
+  std::copy(LineOffsets.begin(), LineOffsets.end(), FI->SourceLineCache);
+}
+
+/// getLineNumber - Given a SourceLocation, return the spelling line number
+/// for the position indicated.  This requires building and caching a table of
+/// line offsets for the MemoryBuffer, so this is not cheap: use only when
+/// about to emit a diagnostic.
+unsigned SourceManager::getLineNumber(FileID FID, unsigned FilePos, 
+                                      bool *Invalid) const {
+  if (FID.isInvalid()) {
+    if (Invalid)
+      *Invalid = true;
+    return 1;
+  }
+
+  ContentCache *Content;
+  if (LastLineNoFileIDQuery == FID)
+    Content = LastLineNoContentCache;
+  else {
+    bool MyInvalid = false;
+    const SLocEntry &Entry = getSLocEntry(FID, &MyInvalid);
+    if (MyInvalid || !Entry.isFile()) {
+      if (Invalid)
+        *Invalid = true;
+      return 1;
+    }
+    
+    Content = const_cast<ContentCache*>(Entry.getFile().getContentCache());
+  }
+  
+  // If this is the first use of line information for this buffer, compute the
+  /// SourceLineCache for it on demand.
+  if (Content->SourceLineCache == 0) {
+    bool MyInvalid = false;
+    ComputeLineNumbers(Diag, Content, ContentCacheAlloc, *this, MyInvalid);
+    if (Invalid)
+      *Invalid = MyInvalid;
+    if (MyInvalid)
+      return 1;
+  } else if (Invalid)
+    *Invalid = false;
+
+  // Okay, we know we have a line number table.  Do a binary search to find the
+  // line number that this character position lands on.
+  unsigned *SourceLineCache = Content->SourceLineCache;
+  unsigned *SourceLineCacheStart = SourceLineCache;
+  unsigned *SourceLineCacheEnd = SourceLineCache + Content->NumLines;
+
+  unsigned QueriedFilePos = FilePos+1;
+
+  // FIXME: I would like to be convinced that this code is worth being as
+  // complicated as it is, binary search isn't that slow.
+  //
+  // If it is worth being optimized, then in my opinion it could be more
+  // performant, simpler, and more obviously correct by just "galloping" outward
+  // from the queried file position. In fact, this could be incorporated into a
+  // generic algorithm such as lower_bound_with_hint.
+  //
+  // If someone gives me a test case where this matters, and I will do it! - DWD
+
+  // If the previous query was to the same file, we know both the file pos from
+  // that query and the line number returned.  This allows us to narrow the
+  // search space from the entire file to something near the match.
+  if (LastLineNoFileIDQuery == FID) {
+    if (QueriedFilePos >= LastLineNoFilePos) {
+      // FIXME: Potential overflow?
+      SourceLineCache = SourceLineCache+LastLineNoResult-1;
+
+      // The query is likely to be nearby the previous one.  Here we check to
+      // see if it is within 5, 10 or 20 lines.  It can be far away in cases
+      // where big comment blocks and vertical whitespace eat up lines but
+      // contribute no tokens.
+      if (SourceLineCache+5 < SourceLineCacheEnd) {
+        if (SourceLineCache[5] > QueriedFilePos)
+          SourceLineCacheEnd = SourceLineCache+5;
+        else if (SourceLineCache+10 < SourceLineCacheEnd) {
+          if (SourceLineCache[10] > QueriedFilePos)
+            SourceLineCacheEnd = SourceLineCache+10;
+          else if (SourceLineCache+20 < SourceLineCacheEnd) {
+            if (SourceLineCache[20] > QueriedFilePos)
+              SourceLineCacheEnd = SourceLineCache+20;
+          }
+        }
+      }
+    } else {
+      if (LastLineNoResult < Content->NumLines)
+        SourceLineCacheEnd = SourceLineCache+LastLineNoResult+1;
+    }
+  }
+
+  // If the spread is large, do a "radix" test as our initial guess, based on
+  // the assumption that lines average to approximately the same length.
+  // NOTE: This is currently disabled, as it does not appear to be profitable in
+  // initial measurements.
+  if (0 && SourceLineCacheEnd-SourceLineCache > 20) {
+    unsigned FileLen = Content->SourceLineCache[Content->NumLines-1];
+
+    // Take a stab at guessing where it is.
+    unsigned ApproxPos = Content->NumLines*QueriedFilePos / FileLen;
+
+    // Check for -10 and +10 lines.
+    unsigned LowerBound = std::max(int(ApproxPos-10), 0);
+    unsigned UpperBound = std::min(ApproxPos+10, FileLen);
+
+    // If the computed lower bound is less than the query location, move it in.
+    if (SourceLineCache < SourceLineCacheStart+LowerBound &&
+        SourceLineCacheStart[LowerBound] < QueriedFilePos)
+      SourceLineCache = SourceLineCacheStart+LowerBound;
+
+    // If the computed upper bound is greater than the query location, move it.
+    if (SourceLineCacheEnd > SourceLineCacheStart+UpperBound &&
+        SourceLineCacheStart[UpperBound] >= QueriedFilePos)
+      SourceLineCacheEnd = SourceLineCacheStart+UpperBound;
+  }
+
+  unsigned *Pos
+    = std::lower_bound(SourceLineCache, SourceLineCacheEnd, QueriedFilePos);
+  unsigned LineNo = Pos-SourceLineCacheStart;
+
+  LastLineNoFileIDQuery = FID;
+  LastLineNoContentCache = Content;
+  LastLineNoFilePos = QueriedFilePos;
+  LastLineNoResult = LineNo;
+  return LineNo;
+}
+
+unsigned SourceManager::getSpellingLineNumber(SourceLocation Loc, 
+                                              bool *Invalid) const {
+  if (isInvalid(Loc, Invalid)) return 0;
+  std::pair<FileID, unsigned> LocInfo = getDecomposedSpellingLoc(Loc);
+  return getLineNumber(LocInfo.first, LocInfo.second);
+}
+unsigned SourceManager::getExpansionLineNumber(SourceLocation Loc,
+                                               bool *Invalid) const {
+  if (isInvalid(Loc, Invalid)) return 0;
+  std::pair<FileID, unsigned> LocInfo = getDecomposedExpansionLoc(Loc);
+  return getLineNumber(LocInfo.first, LocInfo.second);
+}
+unsigned SourceManager::getPresumedLineNumber(SourceLocation Loc,
+                                              bool *Invalid) const {
+  if (isInvalid(Loc, Invalid)) return 0;
+  return getPresumedLoc(Loc).getLine();
+}
+
+/// getFileCharacteristic - return the file characteristic of the specified
+/// source location, indicating whether this is a normal file, a system
+/// header, or an "implicit extern C" system header.
+///
+/// This state can be modified with flags on GNU linemarker directives like:
+///   # 4 "foo.h" 3
+/// which changes all source locations in the current file after that to be
+/// considered to be from a system header.
+SrcMgr::CharacteristicKind
+SourceManager::getFileCharacteristic(SourceLocation Loc) const {
+  assert(!Loc.isInvalid() && "Can't get file characteristic of invalid loc!");
+  std::pair<FileID, unsigned> LocInfo = getDecomposedExpansionLoc(Loc);
+  bool Invalid = false;
+  const SLocEntry &SEntry = getSLocEntry(LocInfo.first, &Invalid);
+  if (Invalid || !SEntry.isFile())
+    return C_User;
+  
+  const SrcMgr::FileInfo &FI = SEntry.getFile();
+
+  // If there are no #line directives in this file, just return the whole-file
+  // state.
+  if (!FI.hasLineDirectives())
+    return FI.getFileCharacteristic();
+
+  assert(LineTable && "Can't have linetable entries without a LineTable!");
+  // See if there is a #line directive before the location.
+  const LineEntry *Entry =
+    LineTable->FindNearestLineEntry(LocInfo.first.ID, LocInfo.second);
+
+  // If this is before the first line marker, use the file characteristic.
+  if (!Entry)
+    return FI.getFileCharacteristic();
+
+  return Entry->FileKind;
+}
+
+/// Return the filename or buffer identifier of the buffer the location is in.
+/// Note that this name does not respect #line directives.  Use getPresumedLoc
+/// for normal clients.
+const char *SourceManager::getBufferName(SourceLocation Loc, 
+                                         bool *Invalid) const {
+  if (isInvalid(Loc, Invalid)) return "<invalid loc>";
+
+  return getBuffer(getFileID(Loc), Invalid)->getBufferIdentifier();
+}
+
+
+/// getPresumedLoc - This method returns the "presumed" location of a
+/// SourceLocation specifies.  A "presumed location" can be modified by #line
+/// or GNU line marker directives.  This provides a view on the data that a
+/// user should see in diagnostics, for example.
+///
+/// Note that a presumed location is always given as the expansion point of an
+/// expansion location, not at the spelling location.
+PresumedLoc SourceManager::getPresumedLoc(SourceLocation Loc) const {
+  if (Loc.isInvalid()) return PresumedLoc();
+
+  // Presumed locations are always for expansion points.
+  std::pair<FileID, unsigned> LocInfo = getDecomposedExpansionLoc(Loc);
+
+  bool Invalid = false;
+  const SLocEntry &Entry = getSLocEntry(LocInfo.first, &Invalid);
+  if (Invalid || !Entry.isFile())
+    return PresumedLoc();
+  
+  const SrcMgr::FileInfo &FI = Entry.getFile();
+  const SrcMgr::ContentCache *C = FI.getContentCache();
+
+  // To get the source name, first consult the FileEntry (if one exists)
+  // before the MemBuffer as this will avoid unnecessarily paging in the
+  // MemBuffer.
+  const char *Filename;
+  if (C->OrigEntry)
+    Filename = C->OrigEntry->getName();
+  else
+    Filename = C->getBuffer(Diag, *this)->getBufferIdentifier();
+
+  unsigned LineNo = getLineNumber(LocInfo.first, LocInfo.second, &Invalid);
+  if (Invalid)
+    return PresumedLoc();
+  unsigned ColNo  = getColumnNumber(LocInfo.first, LocInfo.second, &Invalid);
+  if (Invalid)
+    return PresumedLoc();
+  
+  SourceLocation IncludeLoc = FI.getIncludeLoc();
+
+  // If we have #line directives in this file, update and overwrite the physical
+  // location info if appropriate.
+  if (FI.hasLineDirectives()) {
+    assert(LineTable && "Can't have linetable entries without a LineTable!");
+    // See if there is a #line directive before this.  If so, get it.
+    if (const LineEntry *Entry =
+          LineTable->FindNearestLineEntry(LocInfo.first.ID, LocInfo.second)) {
+      // If the LineEntry indicates a filename, use it.
+      if (Entry->FilenameID != -1)
+        Filename = LineTable->getFilename(Entry->FilenameID);
+
+      // Use the line number specified by the LineEntry.  This line number may
+      // be multiple lines down from the line entry.  Add the difference in
+      // physical line numbers from the query point and the line marker to the
+      // total.
+      unsigned MarkerLineNo = getLineNumber(LocInfo.first, Entry->FileOffset);
+      LineNo = Entry->LineNo + (LineNo-MarkerLineNo-1);
+
+      // Note that column numbers are not molested by line markers.
+
+      // Handle virtual #include manipulation.
+      if (Entry->IncludeOffset) {
+        IncludeLoc = getLocForStartOfFile(LocInfo.first);
+        IncludeLoc = IncludeLoc.getLocWithOffset(Entry->IncludeOffset);
+      }
+    }
+  }
+
+  return PresumedLoc(Filename, LineNo, ColNo, IncludeLoc);
+}
+
+/// \brief The size of the SLocEnty that \arg FID represents.
+unsigned SourceManager::getFileIDSize(FileID FID) const {
+  bool Invalid = false;
+  const SrcMgr::SLocEntry &Entry = getSLocEntry(FID, &Invalid);
+  if (Invalid)
+    return 0;
+
+  int ID = FID.ID;
+  unsigned NextOffset;
+  if ((ID > 0 && unsigned(ID+1) == local_sloc_entry_size()))
+    NextOffset = getNextLocalOffset();
+  else if (ID+1 == -1)
+    NextOffset = MaxLoadedOffset;
+  else
+    NextOffset = getSLocEntry(FileID::get(ID+1)).getOffset();
+
+  return NextOffset - Entry.getOffset() - 1;
+}
+
+//===----------------------------------------------------------------------===//
+// Other miscellaneous methods.
+//===----------------------------------------------------------------------===//
+
+/// \brief Retrieve the inode for the given file entry, if possible.
+///
+/// This routine involves a system call, and therefore should only be used
+/// in non-performance-critical code.
+static llvm::Optional<ino_t> getActualFileInode(const FileEntry *File) {
+  if (!File)
+    return llvm::Optional<ino_t>();
+  
+  struct stat StatBuf;
+  if (::stat(File->getName(), &StatBuf))
+    return llvm::Optional<ino_t>();
+    
+  return StatBuf.st_ino;
+}
+
+/// \brief Get the source location for the given file:line:col triplet.
+///
+/// If the source file is included multiple times, the source location will
+/// be based upon an arbitrary inclusion.
+SourceLocation SourceManager::translateFileLineCol(const FileEntry *SourceFile,
+                                                  unsigned Line,
+                                                  unsigned Col) const {
+  assert(SourceFile && "Null source file!");
+  assert(Line && Col && "Line and column should start from 1!");
+
+  FileID FirstFID = translateFile(SourceFile);
+  return translateLineCol(FirstFID, Line, Col);
+}
+
+/// \brief Get the FileID for the given file.
+///
+/// If the source file is included multiple times, the FileID will be the
+/// first inclusion.
+FileID SourceManager::translateFile(const FileEntry *SourceFile) const {
+  assert(SourceFile && "Null source file!");
+
+  // Find the first file ID that corresponds to the given file.
+  FileID FirstFID;
+
+  // First, check the main file ID, since it is common to look for a
+  // location in the main file.
+  llvm::Optional<ino_t> SourceFileInode;
+  llvm::Optional<StringRef> SourceFileName;
+  if (!MainFileID.isInvalid()) {
+    bool Invalid = false;
+    const SLocEntry &MainSLoc = getSLocEntry(MainFileID, &Invalid);
+    if (Invalid)
+      return FileID();
+    
+    if (MainSLoc.isFile()) {
+      const ContentCache *MainContentCache
+        = MainSLoc.getFile().getContentCache();
+      if (!MainContentCache) {
+        // Can't do anything
+      } else if (MainContentCache->OrigEntry == SourceFile) {
+        FirstFID = MainFileID;
+      } else {
+        // Fall back: check whether we have the same base name and inode
+        // as the main file.
+        const FileEntry *MainFile = MainContentCache->OrigEntry;
+        SourceFileName = llvm::sys::path::filename(SourceFile->getName());
+        if (*SourceFileName == llvm::sys::path::filename(MainFile->getName())) {
+          SourceFileInode = getActualFileInode(SourceFile);
+          if (SourceFileInode) {
+            if (llvm::Optional<ino_t> MainFileInode 
+                                               = getActualFileInode(MainFile)) {
+              if (*SourceFileInode == *MainFileInode) {
+                FirstFID = MainFileID;
+                SourceFile = MainFile;
+              }
+            }
+          }
+        }
+      }
+    }
+  }
+
+  if (FirstFID.isInvalid()) {
+    // The location we're looking for isn't in the main file; look
+    // through all of the local source locations.
+    for (unsigned I = 0, N = local_sloc_entry_size(); I != N; ++I) {
+      bool Invalid = false;
+      const SLocEntry &SLoc = getLocalSLocEntry(I, &Invalid);
+      if (Invalid)
+        return FileID();
+      
+      if (SLoc.isFile() && 
+          SLoc.getFile().getContentCache() &&
+          SLoc.getFile().getContentCache()->OrigEntry == SourceFile) {
+        FirstFID = FileID::get(I);
+        break;
+      }
+    }
+    // If that still didn't help, try the modules.
+    if (FirstFID.isInvalid()) {
+      for (unsigned I = 0, N = loaded_sloc_entry_size(); I != N; ++I) {
+        const SLocEntry &SLoc = getLoadedSLocEntry(I);
+        if (SLoc.isFile() && 
+            SLoc.getFile().getContentCache() &&
+            SLoc.getFile().getContentCache()->OrigEntry == SourceFile) {
+          FirstFID = FileID::get(-int(I) - 2);
+          break;
+        }
+      }
+    }
+  }
+
+  // If we haven't found what we want yet, try again, but this time stat()
+  // each of the files in case the files have changed since we originally 
+  // parsed the file. 
+  if (FirstFID.isInvalid() &&
+      (SourceFileName || 
+       (SourceFileName = llvm::sys::path::filename(SourceFile->getName()))) &&
+      (SourceFileInode ||
+       (SourceFileInode = getActualFileInode(SourceFile)))) {
+    bool Invalid = false;
+    for (unsigned I = 0, N = local_sloc_entry_size(); I != N; ++I) {
+      FileID IFileID;
+      IFileID.ID = I;
+      const SLocEntry &SLoc = getSLocEntry(IFileID, &Invalid);
+      if (Invalid)
+        return FileID();
+      
+      if (SLoc.isFile()) { 
+        const ContentCache *FileContentCache 
+          = SLoc.getFile().getContentCache();
+      const FileEntry *Entry =FileContentCache? FileContentCache->OrigEntry : 0;
+        if (Entry && 
+            *SourceFileName == llvm::sys::path::filename(Entry->getName())) {
+          if (llvm::Optional<ino_t> EntryInode = getActualFileInode(Entry)) {
+            if (*SourceFileInode == *EntryInode) {
+              FirstFID = FileID::get(I);
+              SourceFile = Entry;
+              break;
+            }
+          }
+        }
+      }
+    }      
+  }
+  
+  return FirstFID;
+}
+
+/// \brief Get the source location in \arg FID for the given line:col.
+/// Returns null location if \arg FID is not a file SLocEntry.
+SourceLocation SourceManager::translateLineCol(FileID FID,
+                                               unsigned Line,
+                                               unsigned Col) const {
+  if (FID.isInvalid())
+    return SourceLocation();
+
+  bool Invalid = false;
+  const SLocEntry &Entry = getSLocEntry(FID, &Invalid);
+  if (Invalid)
+    return SourceLocation();
+  
+  if (!Entry.isFile())
+    return SourceLocation();
+
+  SourceLocation FileLoc = SourceLocation::getFileLoc(Entry.getOffset());
+
+  if (Line == 1 && Col == 1)
+    return FileLoc;
+
+  ContentCache *Content
+    = const_cast<ContentCache *>(Entry.getFile().getContentCache());
+  if (!Content)
+    return SourceLocation();
+    
+  // If this is the first use of line information for this buffer, compute the
+  // SourceLineCache for it on demand.
+  if (Content->SourceLineCache == 0) {
+    bool MyInvalid = false;
+    ComputeLineNumbers(Diag, Content, ContentCacheAlloc, *this, MyInvalid);
+    if (MyInvalid)
+      return SourceLocation();
+  }
+
+  if (Line > Content->NumLines) {
+    unsigned Size = Content->getBuffer(Diag, *this)->getBufferSize();
+    if (Size > 0)
+      --Size;
+    return FileLoc.getLocWithOffset(Size);
+  }
+
+  const llvm::MemoryBuffer *Buffer = Content->getBuffer(Diag, *this);
+  unsigned FilePos = Content->SourceLineCache[Line - 1];
+  const char *Buf = Buffer->getBufferStart() + FilePos;
+  unsigned BufLength = Buffer->getBufferSize() - FilePos;
+  if (BufLength == 0)
+    return FileLoc.getLocWithOffset(FilePos);
+
+  unsigned i = 0;
+
+  // Check that the given column is valid.
+  while (i < BufLength-1 && i < Col-1 && Buf[i] != '\n' && Buf[i] != '\r')
+    ++i;
+  if (i < Col-1)
+    return FileLoc.getLocWithOffset(FilePos + i);
+
+  return FileLoc.getLocWithOffset(FilePos + Col - 1);
+}
+
+/// \brief Compute a map of macro argument chunks to their expanded source
+/// location. Chunks that are not part of a macro argument will map to an
+/// invalid source location. e.g. if a file contains one macro argument at
+/// offset 100 with length 10, this is how the map will be formed:
+///     0   -> SourceLocation()
+///     100 -> Expanded macro arg location
+///     110 -> SourceLocation()
+void SourceManager::computeMacroArgsCache(MacroArgsMap *&CachePtr,
+                                          FileID FID) const {
+  assert(!FID.isInvalid());
+  assert(!CachePtr);
+
+  CachePtr = new MacroArgsMap();
+  MacroArgsMap &MacroArgsCache = *CachePtr;
+  // Initially no macro argument chunk is present.
+  MacroArgsCache.insert(std::make_pair(0, SourceLocation()));
+
+  int ID = FID.ID;
+  while (1) {
+    ++ID;
+    // Stop if there are no more FileIDs to check.
+    if (ID > 0) {
+      if (unsigned(ID) >= local_sloc_entry_size())
+        return;
+    } else if (ID == -1) {
+      return;
+    }
+
+    const SrcMgr::SLocEntry &Entry = getSLocEntryByID(ID);
+    if (Entry.isFile()) {
+      SourceLocation IncludeLoc = Entry.getFile().getIncludeLoc();
+      if (IncludeLoc.isInvalid())
+        continue;
+      if (!isInFileID(IncludeLoc, FID))
+        return; // No more files/macros that may be "contained" in this file.
+
+      // Skip the files/macros of the #include'd file, we only care about macros
+      // that lexed macro arguments from our file.
+      if (Entry.getFile().NumCreatedFIDs)
+        ID += Entry.getFile().NumCreatedFIDs - 1/*because of next ++ID*/;
+      continue;
+    }
+
+    const ExpansionInfo &ExpInfo = Entry.getExpansion();
+
+    if (ExpInfo.getExpansionLocStart().isFileID()) {
+      if (!isInFileID(ExpInfo.getExpansionLocStart(), FID))
+        return; // No more files/macros that may be "contained" in this file.
+    }
+
+    if (!ExpInfo.isMacroArgExpansion())
+      continue;
+
+    SourceLocation SpellLoc = ExpInfo.getSpellingLoc();
+    while (!SpellLoc.isFileID()) {
+      std::pair<FileID, unsigned> LocInfo = getDecomposedLoc(SpellLoc);
+      const ExpansionInfo &Info = getSLocEntry(LocInfo.first).getExpansion();
+      if (!Info.isMacroArgExpansion())
+        break;
+      SpellLoc = Info.getSpellingLoc().getLocWithOffset(LocInfo.second);
+    }
+    if (!SpellLoc.isFileID())
+      continue;
+    
+    unsigned BeginOffs;
+    if (!isInFileID(SpellLoc, FID, &BeginOffs))
+      continue;
+
+    unsigned EndOffs = BeginOffs + getFileIDSize(FileID::get(ID));
+
+    // Add a new chunk for this macro argument. A previous macro argument chunk
+    // may have been lexed again, so e.g. if the map is
+    //     0   -> SourceLocation()
+    //     100 -> Expanded loc #1
+    //     110 -> SourceLocation()
+    // and we found a new macro FileID that lexed from offet 105 with length 3,
+    // the new map will be:
+    //     0   -> SourceLocation()
+    //     100 -> Expanded loc #1
+    //     105 -> Expanded loc #2
+    //     108 -> Expanded loc #1
+    //     110 -> SourceLocation()
+    //
+    // Since re-lexed macro chunks will always be the same size or less of
+    // previous chunks, we only need to find where the ending of the new macro
+    // chunk is mapped to and update the map with new begin/end mappings.
+
+    MacroArgsMap::iterator I = MacroArgsCache.upper_bound(EndOffs);
+    --I;
+    SourceLocation EndOffsMappedLoc = I->second;
+    MacroArgsCache[BeginOffs] = SourceLocation::getMacroLoc(Entry.getOffset());
+    MacroArgsCache[EndOffs] = EndOffsMappedLoc;
+  }
+}
+
+/// \brief If \arg Loc points inside a function macro argument, the returned
+/// location will be the macro location in which the argument was expanded.
+/// If a macro argument is used multiple times, the expanded location will
+/// be at the first expansion of the argument.
+/// e.g.
+///   MY_MACRO(foo);
+///             ^
+/// Passing a file location pointing at 'foo', will yield a macro location
+/// where 'foo' was expanded into.
+SourceLocation
+SourceManager::getMacroArgExpandedLocation(SourceLocation Loc) const {
+  if (Loc.isInvalid() || !Loc.isFileID())
+    return Loc;
+
+  FileID FID;
+  unsigned Offset;
+  llvm::tie(FID, Offset) = getDecomposedLoc(Loc);
+  if (FID.isInvalid())
+    return Loc;
+
+  MacroArgsMap *&MacroArgsCache = MacroArgsCacheMap[FID];
+  if (!MacroArgsCache)
+    computeMacroArgsCache(MacroArgsCache, FID);
+
+  assert(!MacroArgsCache->empty());
+  MacroArgsMap::iterator I = MacroArgsCache->upper_bound(Offset);
+  --I;
+  
+  unsigned MacroArgBeginOffs = I->first;
+  SourceLocation MacroArgExpandedLoc = I->second;
+  if (MacroArgExpandedLoc.isValid())
+    return MacroArgExpandedLoc.getLocWithOffset(Offset - MacroArgBeginOffs);
+
+  return Loc;
+}
+
+/// Given a decomposed source location, move it up the include/expansion stack
+/// to the parent source location.  If this is possible, return the decomposed
+/// version of the parent in Loc and return false.  If Loc is the top-level
+/// entry, return true and don't modify it.
+static bool MoveUpIncludeHierarchy(std::pair<FileID, unsigned> &Loc,
+                                   const SourceManager &SM) {
+  SourceLocation UpperLoc;
+  const SrcMgr::SLocEntry &Entry = SM.getSLocEntry(Loc.first);
+  if (Entry.isExpansion())
+    UpperLoc = Entry.getExpansion().getExpansionLocStart();
+  else
+    UpperLoc = Entry.getFile().getIncludeLoc();
+  
+  if (UpperLoc.isInvalid())
+    return true; // We reached the top.
+  
+  Loc = SM.getDecomposedLoc(UpperLoc);
+  return false;
+}
+  
+
+/// \brief Determines the order of 2 source locations in the translation unit.
+///
+/// \returns true if LHS source location comes before RHS, false otherwise.
+bool SourceManager::isBeforeInTranslationUnit(SourceLocation LHS,
+                                              SourceLocation RHS) const {
+  assert(LHS.isValid() && RHS.isValid() && "Passed invalid source location!");
+  if (LHS == RHS)
+    return false;
+
+  std::pair<FileID, unsigned> LOffs = getDecomposedLoc(LHS);
+  std::pair<FileID, unsigned> ROffs = getDecomposedLoc(RHS);
+
+  // If the source locations are in the same file, just compare offsets.
+  if (LOffs.first == ROffs.first)
+    return LOffs.second < ROffs.second;
+
+  // If we are comparing a source location with multiple locations in the same
+  // file, we get a big win by caching the result.
+  if (IsBeforeInTUCache.isCacheValid(LOffs.first, ROffs.first))
+    return IsBeforeInTUCache.getCachedResult(LOffs.second, ROffs.second);
+
+  // Okay, we missed in the cache, start updating the cache for this query.
+  IsBeforeInTUCache.setQueryFIDs(LOffs.first, ROffs.first,
+                          /*isLFIDBeforeRFID=*/LOffs.first.ID < ROffs.first.ID);
+
+  // We need to find the common ancestor. The only way of doing this is to
+  // build the complete include chain for one and then walking up the chain
+  // of the other looking for a match.
+  // We use a map from FileID to Offset to store the chain. Easier than writing
+  // a custom set hash info that only depends on the first part of a pair.
+  typedef llvm::DenseMap<FileID, unsigned> LocSet;
+  LocSet LChain;
+  do {
+    LChain.insert(LOffs);
+    // We catch the case where LOffs is in a file included by ROffs and
+    // quit early. The other way round unfortunately remains suboptimal.
+  } while (LOffs.first != ROffs.first && !MoveUpIncludeHierarchy(LOffs, *this));
+  LocSet::iterator I;
+  while((I = LChain.find(ROffs.first)) == LChain.end()) {
+    if (MoveUpIncludeHierarchy(ROffs, *this))
+      break; // Met at topmost file.
+  }
+  if (I != LChain.end())
+    LOffs = *I;
+
+  // If we exited because we found a nearest common ancestor, compare the
+  // locations within the common file and cache them.
+  if (LOffs.first == ROffs.first) {
+    IsBeforeInTUCache.setCommonLoc(LOffs.first, LOffs.second, ROffs.second);
+    return IsBeforeInTUCache.getCachedResult(LOffs.second, ROffs.second);
+  }
+
+  // This can happen if a location is in a built-ins buffer.
+  // But see PR5662.
+  // Clear the lookup cache, it depends on a common location.
+  IsBeforeInTUCache.clear();
+  bool LIsBuiltins = strcmp("<built-in>",
+                            getBuffer(LOffs.first)->getBufferIdentifier()) == 0;
+  bool RIsBuiltins = strcmp("<built-in>",
+                            getBuffer(ROffs.first)->getBufferIdentifier()) == 0;
+  // built-in is before non-built-in
+  if (LIsBuiltins != RIsBuiltins)
+    return LIsBuiltins;
+  assert(LIsBuiltins && RIsBuiltins &&
+         "Non-built-in locations must be rooted in the main file");
+  // Both are in built-in buffers, but from different files. We just claim that
+  // lower IDs come first.
+  return LOffs.first < ROffs.first;
+}
+
+/// PrintStats - Print statistics to stderr.
+///
+void SourceManager::PrintStats() const {
+  llvm::errs() << "\n*** Source Manager Stats:\n";
+  llvm::errs() << FileInfos.size() << " files mapped, " << MemBufferInfos.size()
+               << " mem buffers mapped.\n";
+  llvm::errs() << LocalSLocEntryTable.size() << " local SLocEntry's allocated ("
+               << llvm::capacity_in_bytes(LocalSLocEntryTable)
+               << " bytes of capacity), "
+               << NextLocalOffset << "B of Sloc address space used.\n";
+  llvm::errs() << LoadedSLocEntryTable.size()
+               << " loaded SLocEntries allocated, "
+               << MaxLoadedOffset - CurrentLoadedOffset
+               << "B of Sloc address space used.\n";
+  
+  unsigned NumLineNumsComputed = 0;
+  unsigned NumFileBytesMapped = 0;
+  for (fileinfo_iterator I = fileinfo_begin(), E = fileinfo_end(); I != E; ++I){
+    NumLineNumsComputed += I->second->SourceLineCache != 0;
+    NumFileBytesMapped  += I->second->getSizeBytesMapped();
+  }
+  unsigned NumMacroArgsComputed = MacroArgsCacheMap.size();
+
+  llvm::errs() << NumFileBytesMapped << " bytes of files mapped, "
+               << NumLineNumsComputed << " files with line #'s computed, "
+               << NumMacroArgsComputed << " files with macro args computed.\n";
+  llvm::errs() << "FileID scans: " << NumLinearScans << " linear, "
+               << NumBinaryProbes << " binary.\n";
+}
+
+ExternalSLocEntrySource::~ExternalSLocEntrySource() { }
+
+/// Return the amount of memory used by memory buffers, breaking down
+/// by heap-backed versus mmap'ed memory.
+SourceManager::MemoryBufferSizes SourceManager::getMemoryBufferSizes() const {
+  size_t malloc_bytes = 0;
+  size_t mmap_bytes = 0;
+  
+  for (unsigned i = 0, e = MemBufferInfos.size(); i != e; ++i)
+    if (size_t sized_mapped = MemBufferInfos[i]->getSizeBytesMapped())
+      switch (MemBufferInfos[i]->getMemoryBufferKind()) {
+        case llvm::MemoryBuffer::MemoryBuffer_MMap:
+          mmap_bytes += sized_mapped;
+          break;
+        case llvm::MemoryBuffer::MemoryBuffer_Malloc:
+          malloc_bytes += sized_mapped;
+          break;
+      }
+  
+  return MemoryBufferSizes(malloc_bytes, mmap_bytes);
+}
+
+size_t SourceManager::getDataStructureSizes() const {
+  return llvm::capacity_in_bytes(MemBufferInfos)
+    + llvm::capacity_in_bytes(LocalSLocEntryTable)
+    + llvm::capacity_in_bytes(LoadedSLocEntryTable)
+    + llvm::capacity_in_bytes(SLocEntryLoaded)
+    + llvm::capacity_in_bytes(FileInfos)
+    + llvm::capacity_in_bytes(OverriddenFiles);
+}