Graduate the TextDiagnostic interface to its own header and source file,

making it accessible to anyone from the Frontend library. Still a good
bit of cleanup to do here, but its a good milestone. This ensures that
*all* of the functionality needed to implement the DiagnosticConsumer is
exposed via the generic interface in some form. No sneaky re-use of
static functions.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@142086 91177308-0d34-0410-b5e6-96231b3b80d8

4 files changed, 1278 insertions, 1155 deletions

diff --git a/include/clang/Frontend/TextDiagnostic.h b/include/clang/Frontend/TextDiagnostic.h
new file mode 100644
index 0000000000..5140abf8ae
--- /dev/null
+++ b/include/clang/Frontend/TextDiagnostic.h
@@ -0,0 +1,178 @@
+//===--- TextDiagnostic.h - Text Diagnostic Pretty-Printing -----*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This is a utility class that provides support for textual pretty-printing of
+// diagnostics. It is used to implement the different code paths which require
+// such functionality in a consistent way.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_CLANG_FRONTEND_TEXT_DIAGNOSTIC_H_
+#define LLVM_CLANG_FRONTEND_TEXT_DIAGNOSTIC_H_
+
+#include "clang/Basic/Diagnostic.h"
+#include "clang/Basic/LLVM.h"
+#include "clang/Basic/SourceLocation.h"
+
+namespace clang {
+class DiagnosticOptions;
+class LangOptions;
+class SourceManager;
+
+/// \brief Class to encapsulate the logic for formatting and printing a textual
+/// diagnostic message.
+///
+/// This class provides an interface for building and emitting a textual
+/// diagnostic, including all of the macro backtraces, caret diagnostics, FixIt
+/// Hints, and code snippets. In the presence of macros this involves
+/// a recursive process, synthesizing notes for each macro expansion.
+///
+/// The purpose of this class is to isolate the implementation of printing
+/// beautiful text diagnostics from any particular interfaces. The Clang
+/// DiagnosticClient is implemented through this class as is diagnostic
+/// printing coming out of libclang.
+///
+/// A brief worklist:
+/// FIXME: Sink the recursive printing of template instantiations into this
+/// class.
+class TextDiagnostic {
+  raw_ostream &OS;
+  const SourceManager &SM;
+  const LangOptions &LangOpts;
+  const DiagnosticOptions &DiagOpts;
+
+  /// \brief The location of the previous diagnostic if known.
+  ///
+  /// This will be invalid in cases where there is no (known) previous
+  /// diagnostic location, or that location itself is invalid or comes from
+  /// a different source manager than SM.
+  SourceLocation LastLoc;
+
+  /// \brief The location of the last include whose stack was printed if known.
+  ///
+  /// Same restriction as \see LastLoc essentially, but tracking include stack
+  /// root locations rather than diagnostic locations.
+  SourceLocation LastIncludeLoc;
+
+  /// \brief The level of the last diagnostic emitted.
+  ///
+  /// The level of the last diagnostic emitted. Used to detect level changes
+  /// which change the amount of information displayed.
+  DiagnosticsEngine::Level LastLevel;
+
+public:
+  TextDiagnostic(raw_ostream &OS,
+                 const SourceManager &SM,
+                 const LangOptions &LangOpts,
+                 const DiagnosticOptions &DiagOpts,
+                 FullSourceLoc LastLoc = FullSourceLoc(),
+                 FullSourceLoc LastIncludeLoc = FullSourceLoc(),
+                 DiagnosticsEngine::Level LastLevel
+                   = DiagnosticsEngine::Level());
+
+  /// \brief Get the last diagnostic location emitted.
+  SourceLocation getLastLoc() const { return LastLoc; }
+
+  /// \brief Get the last emitted include stack location.
+  SourceLocation getLastIncludeLoc() const { return LastIncludeLoc; }
+
+  /// \brief Get the last diagnostic level.
+  DiagnosticsEngine::Level getLastLevel() const { return LastLevel; }
+
+  void Emit(SourceLocation Loc, DiagnosticsEngine::Level Level,
+            StringRef Message, ArrayRef<CharSourceRange> Ranges,
+            ArrayRef<FixItHint> FixItHints,
+            bool LastCaretDiagnosticWasNote = false);
+
+  /// \brief Emit the caret and underlining text.
+  ///
+  /// Walks up the macro expansion stack printing the code snippet, caret,
+  /// underlines and FixItHint display as appropriate at each level. Walk is
+  /// accomplished by calling itself recursively.
+  ///
+  /// FIXME: Remove macro expansion from this routine, it shouldn't be tied to
+  /// caret diagnostics.
+  /// FIXME: Break up massive function into logical units.
+  ///
+  /// \param Loc The location for this caret.
+  /// \param Ranges The underlined ranges for this code snippet.
+  /// \param Hints The FixIt hints active for this diagnostic.
+  /// \param MacroSkipEnd The depth to stop skipping macro expansions.
+  /// \param OnMacroInst The current depth of the macro expansion stack.
+  void EmitCaret(SourceLocation Loc,
+                 SmallVectorImpl<CharSourceRange>& Ranges,
+                 ArrayRef<FixItHint> Hints,
+                 unsigned &MacroDepth,
+                 unsigned OnMacroInst = 0);
+
+  /// \brief Emit a code snippet and caret line.
+  ///
+  /// This routine emits a single line's code snippet and caret line..
+  ///
+  /// \param Loc The location for the caret.
+  /// \param Ranges The underlined ranges for this code snippet.
+  /// \param Hints The FixIt hints active for this diagnostic.
+  void EmitSnippetAndCaret(SourceLocation Loc,
+                           SmallVectorImpl<CharSourceRange>& Ranges,
+                           ArrayRef<FixItHint> Hints);
+
+  /// \brief Print the diagonstic level to a raw_ostream.
+  ///
+  /// This is a static helper that handles colorizing the level and formatting
+  /// it into an arbitrary output stream. This is used internally by the
+  /// TextDiagnostic emission code, but it can also be used directly by
+  /// consumers that don't have a source manager or other state that the full
+  /// TextDiagnostic logic requires.
+  static void printDiagnosticLevel(raw_ostream &OS,
+                                   DiagnosticsEngine::Level Level,
+                                   bool ShowColors);
+
+  /// \brief Pretty-print a diagnostic message to a raw_ostream.
+  ///
+  /// This is a static helper to handle the line wrapping, colorizing, and
+  /// rendering of a diagnostic message to a particular ostream. It is
+  /// publically visible so that clients which do not have sufficient state to
+  /// build a complete TextDiagnostic object can still get consistent
+  /// formatting of their diagnostic messages.
+  ///
+  /// \param OS Where the message is printed
+  /// \param Level Used to colorizing the message
+  /// \param Message The text actually printed
+  /// \param CurrentColumn The starting column of the first line, accounting
+  ///                      for any prefix.
+  /// \param Columns The number of columns to use in line-wrapping, 0 disables
+  ///                all line-wrapping.
+  /// \param ShowColors Enable colorizing of the message.
+  static void printDiagnosticMessage(raw_ostream &OS,
+                                     DiagnosticsEngine::Level Level,
+                                     StringRef Message,
+                                     unsigned CurrentColumn, unsigned Columns,
+                                     bool ShowColors);
+
+private:
+  void emitIncludeStack(SourceLocation Loc, DiagnosticsEngine::Level Level);
+  void emitIncludeStackRecursively(SourceLocation Loc);
+  void EmitDiagnosticLoc(SourceLocation Loc, PresumedLoc PLoc,
+                         DiagnosticsEngine::Level Level,
+                         ArrayRef<CharSourceRange> Ranges);
+  void HighlightRange(const CharSourceRange &R,
+                      unsigned LineNo, FileID FID,
+                      const std::string &SourceLine,
+                      std::string &CaretLine);
+  std::string BuildFixItInsertionLine(unsigned LineNo,
+                                      const char *LineStart,
+                                      const char *LineEnd,
+                                      ArrayRef<FixItHint> Hints);
+  void ExpandTabs(std::string &SourceLine, std::string &CaretLine);
+  void EmitParseableFixits(ArrayRef<FixItHint> Hints);
+};
+
+} // end namespace clang
+
+#endif
diff --git a/lib/Frontend/CMakeLists.txt b/lib/Frontend/CMakeLists.txt
index 39128fba38..90fa91d04d 100644
--- a/lib/Frontend/CMakeLists.txt
+++ b/lib/Frontend/CMakeLists.txt
@@ -27,6 +27,7 @@ add_clang_library(clangFrontend
   LogDiagnosticPrinter.cpp
   MultiplexConsumer.cpp
   PrintPreprocessedOutput.cpp
+  TextDiagnostic.cpp
   TextDiagnosticBuffer.cpp
   TextDiagnosticPrinter.cpp
   VerifyDiagnosticConsumer.cpp
diff --git a/lib/Frontend/TextDiagnostic.cpp b/lib/Frontend/TextDiagnostic.cpp
new file mode 100644
index 0000000000..3f55f78cdd
--- /dev/null
+++ b/lib/Frontend/TextDiagnostic.cpp
@@ -0,0 +1,1098 @@
+//===--- TextDiagnostic.cpp - Text Diagnostic Pretty-Printing -------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#include "clang/Frontend/TextDiagnostic.h"
+#include "clang/Basic/FileManager.h"
+#include "clang/Basic/SourceManager.h"
+#include "clang/Frontend/DiagnosticOptions.h"
+#include "clang/Lex/Lexer.h"
+#include "llvm/Support/MemoryBuffer.h"
+#include "llvm/Support/raw_ostream.h"
+#include "llvm/Support/ErrorHandling.h"
+#include "llvm/ADT/SmallString.h"
+#include <algorithm>
+using namespace clang;
+
+static const enum raw_ostream::Colors noteColor =
+  raw_ostream::BLACK;
+static const enum raw_ostream::Colors fixitColor =
+  raw_ostream::GREEN;
+static const enum raw_ostream::Colors caretColor =
+  raw_ostream::GREEN;
+static const enum raw_ostream::Colors warningColor =
+  raw_ostream::MAGENTA;
+static const enum raw_ostream::Colors errorColor = raw_ostream::RED;
+static const enum raw_ostream::Colors fatalColor = raw_ostream::RED;
+// Used for changing only the bold attribute.
+static const enum raw_ostream::Colors savedColor =
+  raw_ostream::SAVEDCOLOR;
+
+/// \brief Number of spaces to indent when word-wrapping.
+const unsigned WordWrapIndentation = 6;
+
+/// \brief When the source code line we want to print is too long for
+/// the terminal, select the "interesting" region.
+static void SelectInterestingSourceRegion(std::string &SourceLine,
+                                          std::string &CaretLine,
+                                          std::string &FixItInsertionLine,
+                                          unsigned EndOfCaretToken,
+                                          unsigned Columns) {
+  unsigned MaxSize = std::max(SourceLine.size(),
+                              std::max(CaretLine.size(), 
+                                       FixItInsertionLine.size()));
+  if (MaxSize > SourceLine.size())
+    SourceLine.resize(MaxSize, ' ');
+  if (MaxSize > CaretLine.size())
+    CaretLine.resize(MaxSize, ' ');
+  if (!FixItInsertionLine.empty() && MaxSize > FixItInsertionLine.size())
+    FixItInsertionLine.resize(MaxSize, ' ');
+    
+  // Find the slice that we need to display the full caret line
+  // correctly.
+  unsigned CaretStart = 0, CaretEnd = CaretLine.size();
+  for (; CaretStart != CaretEnd; ++CaretStart)
+    if (!isspace(CaretLine[CaretStart]))
+      break;
+
+  for (; CaretEnd != CaretStart; --CaretEnd)
+    if (!isspace(CaretLine[CaretEnd - 1]))
+      break;
+
+  // Make sure we don't chop the string shorter than the caret token
+  // itself.
+  if (CaretEnd < EndOfCaretToken)
+    CaretEnd = EndOfCaretToken;
+
+  // If we have a fix-it line, make sure the slice includes all of the
+  // fix-it information.
+  if (!FixItInsertionLine.empty()) {
+    unsigned FixItStart = 0, FixItEnd = FixItInsertionLine.size();
+    for (; FixItStart != FixItEnd; ++FixItStart)
+      if (!isspace(FixItInsertionLine[FixItStart]))
+        break;
+
+    for (; FixItEnd != FixItStart; --FixItEnd)
+      if (!isspace(FixItInsertionLine[FixItEnd - 1]))
+        break;
+
+    if (FixItStart < CaretStart)
+      CaretStart = FixItStart;
+    if (FixItEnd > CaretEnd)
+      CaretEnd = FixItEnd;
+  }
+
+  // CaretLine[CaretStart, CaretEnd) contains all of the interesting
+  // parts of the caret line. While this slice is smaller than the
+  // number of columns we have, try to grow the slice to encompass
+  // more context.
+
+  // If the end of the interesting region comes before we run out of
+  // space in the terminal, start at the beginning of the line.
+  if (Columns > 3 && CaretEnd < Columns - 3)
+    CaretStart = 0;
+
+  unsigned TargetColumns = Columns;
+  if (TargetColumns > 8)
+    TargetColumns -= 8; // Give us extra room for the ellipses.
+  unsigned SourceLength = SourceLine.size();
+  while ((CaretEnd - CaretStart) < TargetColumns) {
+    bool ExpandedRegion = false;
+    // Move the start of the interesting region left until we've
+    // pulled in something else interesting.
+    if (CaretStart == 1)
+      CaretStart = 0;
+    else if (CaretStart > 1) {
+      unsigned NewStart = CaretStart - 1;
+
+      // Skip over any whitespace we see here; we're looking for
+      // another bit of interesting text.
+      while (NewStart && isspace(SourceLine[NewStart]))
+        --NewStart;
+
+      // Skip over this bit of "interesting" text.
+      while (NewStart && !isspace(SourceLine[NewStart]))
+        --NewStart;
+
+      // Move up to the non-whitespace character we just saw.
+      if (NewStart)
+        ++NewStart;
+
+      // If we're still within our limit, update the starting
+      // position within the source/caret line.
+      if (CaretEnd - NewStart <= TargetColumns) {
+        CaretStart = NewStart;
+        ExpandedRegion = true;
+      }
+    }
+
+    // Move the end of the interesting region right until we've
+    // pulled in something else interesting.
+    if (CaretEnd != SourceLength) {
+      assert(CaretEnd < SourceLength && "Unexpected caret position!");
+      unsigned NewEnd = CaretEnd;
+
+      // Skip over any whitespace we see here; we're looking for
+      // another bit of interesting text.
+      while (NewEnd != SourceLength && isspace(SourceLine[NewEnd - 1]))
+        ++NewEnd;
+
+      // Skip over this bit of "interesting" text.
+      while (NewEnd != SourceLength && !isspace(SourceLine[NewEnd - 1]))
+        ++NewEnd;
+
+      if (NewEnd - CaretStart <= TargetColumns) {
+        CaretEnd = NewEnd;
+        ExpandedRegion = true;
+      }
+    }
+
+    if (!ExpandedRegion)
+      break;
+  }
+
+  // [CaretStart, CaretEnd) is the slice we want. Update the various
+  // output lines to show only this slice, with two-space padding
+  // before the lines so that it looks nicer.
+  if (CaretEnd < SourceLine.size())
+    SourceLine.replace(CaretEnd, std::string::npos, "...");
+  if (CaretEnd < CaretLine.size())
+    CaretLine.erase(CaretEnd, std::string::npos);
+  if (FixItInsertionLine.size() > CaretEnd)
+    FixItInsertionLine.erase(CaretEnd, std::string::npos);
+
+  if (CaretStart > 2) {
+    SourceLine.replace(0, CaretStart, "  ...");
+    CaretLine.replace(0, CaretStart, "     ");
+    if (FixItInsertionLine.size() >= CaretStart)
+      FixItInsertionLine.replace(0, CaretStart, "     ");
+  }
+}
+
+/// Look through spelling locations for a macro argument expansion, and
+/// if found skip to it so that we can trace the argument rather than the macros
+/// in which that argument is used. If no macro argument expansion is found,
+/// don't skip anything and return the starting location.
+static SourceLocation skipToMacroArgExpansion(const SourceManager &SM,
+                                                  SourceLocation StartLoc) {
+  for (SourceLocation L = StartLoc; L.isMacroID();
+       L = SM.getImmediateSpellingLoc(L)) {
+    if (SM.isMacroArgExpansion(L))
+      return L;
+  }
+
+  // Otherwise just return initial location, there's nothing to skip.
+  return StartLoc;
+}
+
+/// Gets the location of the immediate macro caller, one level up the stack
+/// toward the initial macro typed into the source.
+static SourceLocation getImmediateMacroCallerLoc(const SourceManager &SM,
+                                                 SourceLocation Loc) {
+  if (!Loc.isMacroID()) return Loc;
+
+  // When we have the location of (part of) an expanded parameter, its spelling
+  // location points to the argument as typed into the macro call, and
+  // therefore is used to locate the macro caller.
+  if (SM.isMacroArgExpansion(Loc))
+    return SM.getImmediateSpellingLoc(Loc);
+
+  // Otherwise, the caller of the macro is located where this macro is
+  // expanded (while the spelling is part of the macro definition).
+  return SM.getImmediateExpansionRange(Loc).first;
+}
+
+/// Gets the location of the immediate macro callee, one level down the stack
+/// toward the leaf macro.
+static SourceLocation getImmediateMacroCalleeLoc(const SourceManager &SM,
+                                                 SourceLocation Loc) {
+  if (!Loc.isMacroID()) return Loc;
+
+  // When we have the location of (part of) an expanded parameter, its
+  // expansion location points to the unexpanded paramater reference within
+  // the macro definition (or callee).
+  if (SM.isMacroArgExpansion(Loc))
+    return SM.getImmediateExpansionRange(Loc).first;
+
+  // Otherwise, the callee of the macro is located where this location was
+  // spelled inside the macro definition.
+  return SM.getImmediateSpellingLoc(Loc);
+}
+
+/// Get the presumed location of a diagnostic message. This computes the
+/// presumed location for the top of any macro backtrace when present.
+static PresumedLoc getDiagnosticPresumedLoc(const SourceManager &SM,
+                                            SourceLocation Loc) {
+  // This is a condensed form of the algorithm used by EmitCaretDiagnostic to
+  // walk to the top of the macro call stack.
+  while (Loc.isMacroID()) {
+    Loc = skipToMacroArgExpansion(SM, Loc);
+    Loc = getImmediateMacroCallerLoc(SM, Loc);
+  }
+
+  return SM.getPresumedLoc(Loc);
+}
+
+/// \brief Skip over whitespace in the string, starting at the given
+/// index.
+///
+/// \returns The index of the first non-whitespace character that is
+/// greater than or equal to Idx or, if no such character exists,
+/// returns the end of the string.
+static unsigned skipWhitespace(unsigned Idx, StringRef Str, unsigned Length) {
+  while (Idx < Length && isspace(Str[Idx]))
+    ++Idx;
+  return Idx;
+}
+
+/// \brief If the given character is the start of some kind of
+/// balanced punctuation (e.g., quotes or parentheses), return the
+/// character that will terminate the punctuation.
+///
+/// \returns The ending punctuation character, if any, or the NULL
+/// character if the input character does not start any punctuation.
+static inline char findMatchingPunctuation(char c) {
+  switch (c) {
+  case '\'': return '\'';
+  case '`': return '\'';
+  case '"':  return '"';
+  case '(':  return ')';
+  case '[': return ']';
+  case '{': return '}';
+  default: break;
+  }
+
+  return 0;
+}
+
+/// \brief Find the end of the word starting at the given offset
+/// within a string.
+///
+/// \returns the index pointing one character past the end of the
+/// word.
+static unsigned findEndOfWord(unsigned Start, StringRef Str,
+                              unsigned Length, unsigned Column,
+                              unsigned Columns) {
+  assert(Start < Str.size() && "Invalid start position!");
+  unsigned End = Start + 1;
+
+  // If we are already at the end of the string, take that as the word.
+  if (End == Str.size())
+    return End;
+
+  // Determine if the start of the string is actually opening
+  // punctuation, e.g., a quote or parentheses.
+  char EndPunct = findMatchingPunctuation(Str[Start]);
+  if (!EndPunct) {
+    // This is a normal word. Just find the first space character.
+    while (End < Length && !isspace(Str[End]))
+      ++End;
+    return End;
+  }
+
+  // We have the start of a balanced punctuation sequence (quotes,
+  // parentheses, etc.). Determine the full sequence is.
+  llvm::SmallString<16> PunctuationEndStack;
+  PunctuationEndStack.push_back(EndPunct);
+  while (End < Length && !PunctuationEndStack.empty()) {
+    if (Str[End] == PunctuationEndStack.back())
+      PunctuationEndStack.pop_back();
+    else if (char SubEndPunct = findMatchingPunctuation(Str[End]))
+      PunctuationEndStack.push_back(SubEndPunct);
+
+    ++End;
+  }
+
+  // Find the first space character after the punctuation ended.
+  while (End < Length && !isspace(Str[End]))
+    ++End;
+
+  unsigned PunctWordLength = End - Start;
+  if (// If the word fits on this line
+      Column + PunctWordLength <= Columns ||
+      // ... or the word is "short enough" to take up the next line
+      // without too much ugly white space
+      PunctWordLength < Columns/3)
+    return End; // Take the whole thing as a single "word".
+
+  // The whole quoted/parenthesized string is too long to print as a
+  // single "word". Instead, find the "word" that starts just after
+  // the punctuation and use that end-point instead. This will recurse
+  // until it finds something small enough to consider a word.
+  return findEndOfWord(Start + 1, Str, Length, Column + 1, Columns);
+}
+
+/// \brief Print the given string to a stream, word-wrapping it to
+/// some number of columns in the process.
+///
+/// \param OS the stream to which the word-wrapping string will be
+/// emitted.
+/// \param Str the string to word-wrap and output.
+/// \param Columns the number of columns to word-wrap to.
+/// \param Column the column number at which the first character of \p
+/// Str will be printed. This will be non-zero when part of the first
+/// line has already been printed.
+/// \param Indentation the number of spaces to indent any lines beyond
+/// the first line.
+/// \returns true if word-wrapping was required, or false if the
+/// string fit on the first line.
+static bool printWordWrapped(raw_ostream &OS, StringRef Str,
+                             unsigned Columns,
+                             unsigned Column = 0,
+                             unsigned Indentation = WordWrapIndentation) {
+  const unsigned Length = std::min(Str.find('\n'), Str.size());
+
+  // The string used to indent each line.
+  llvm::SmallString<16> IndentStr;
+  IndentStr.assign(Indentation, ' ');
+  bool Wrapped = false;
+  for (unsigned WordStart = 0, WordEnd; WordStart < Length;
+       WordStart = WordEnd) {
+    // Find the beginning of the next word.
+    WordStart = skipWhitespace(WordStart, Str, Length);
+    if (WordStart == Length)
+      break;
+
+    // Find the end of this word.
+    WordEnd = findEndOfWord(WordStart, Str, Length, Column, Columns);
+
+    // Does this word fit on the current line?
+    unsigned WordLength = WordEnd - WordStart;
+    if (Column + WordLength < Columns) {
+      // This word fits on the current line; print it there.
+      if (WordStart) {
+        OS << ' ';
+        Column += 1;
+      }
+      OS << Str.substr(WordStart, WordLength);
+      Column += WordLength;
+      continue;
+    }
+
+    // This word does not fit on the current line, so wrap to the next
+    // line.
+    OS << '\n';
+    OS.write(&IndentStr[0], Indentation);
+    OS << Str.substr(WordStart, WordLength);
+    Column = Indentation + WordLength;
+    Wrapped = true;
+  }
+
+  // Append any remaning text from the message with its existing formatting.
+  OS << Str.substr(Length);
+
+  return Wrapped;
+}
+
+TextDiagnostic::TextDiagnostic(raw_ostream &OS,
+                               const SourceManager &SM,
+                               const LangOptions &LangOpts,
+                               const DiagnosticOptions &DiagOpts,
+                               FullSourceLoc LastLoc,
+                               FullSourceLoc LastIncludeLoc,
+                               DiagnosticsEngine::Level LastLevel)
+  : OS(OS), SM(SM), LangOpts(LangOpts), DiagOpts(DiagOpts),
+    LastLoc(LastLoc), LastIncludeLoc(LastIncludeLoc), LastLevel(LastLevel) {
+  if (LastLoc.isValid() && &SM != &LastLoc.getManager())
+    this->LastLoc = SourceLocation();
+  if (LastIncludeLoc.isValid() && &SM != &LastIncludeLoc.getManager())
+    this->LastIncludeLoc = SourceLocation();
+    }
+
+void TextDiagnostic::Emit(SourceLocation Loc, DiagnosticsEngine::Level Level,
+                          StringRef Message, ArrayRef<CharSourceRange> Ranges,
+                          ArrayRef<FixItHint> FixItHints,
+                          bool LastCaretDiagnosticWasNote) {
+  PresumedLoc PLoc = getDiagnosticPresumedLoc(SM, Loc);
+
+  // First, if this diagnostic is not in the main file, print out the
+  // "included from" lines.
+  emitIncludeStack(PLoc.getIncludeLoc(), Level);
+
+  uint64_t StartOfLocationInfo = OS.tell();
+
+  // Next emit the location of this particular diagnostic.
+  EmitDiagnosticLoc(Loc, PLoc, Level, Ranges);
+
+  if (DiagOpts.ShowColors)
+    OS.resetColor();
+
+  printDiagnosticLevel(OS, Level, DiagOpts.ShowColors);
+  printDiagnosticMessage(OS, Level, Message,
+                         OS.tell() - StartOfLocationInfo,
+                         DiagOpts.MessageLength, DiagOpts.ShowColors);
+
+  // If caret diagnostics are enabled and we have location, we want to
+  // emit the caret.  However, we only do this if the location moved
+  // from the last diagnostic, if the last diagnostic was a note that
+  // was part of a different warning or error diagnostic, or if the
+  // diagnostic has ranges.  We don't want to emit the same caret
+  // multiple times if one loc has multiple diagnostics.
+  if (DiagOpts.ShowCarets &&
+      (Loc != LastLoc || !Ranges.empty() || !FixItHints.empty() ||
+       (LastLevel == DiagnosticsEngine::Note && Level != LastLevel))) {
+    // Get the ranges into a local array we can hack on.
+    SmallVector<CharSourceRange, 20> MutableRanges(Ranges.begin(),
+                                                   Ranges.end());
+
+    for (ArrayRef<FixItHint>::const_iterator I = FixItHints.begin(),
+                                             E = FixItHints.end();
+         I != E; ++I)
+      if (I->RemoveRange.isValid())
+        MutableRanges.push_back(I->RemoveRange);
+
+    unsigned MacroDepth = 0;
+    EmitCaret(Loc, MutableRanges, FixItHints, MacroDepth);
+  }
+
+  LastLoc = Loc;
+  LastLevel = Level;
+}
+
+/// \brief Emit the caret and underlining text.
+///
+/// Walks up the macro expansion stack printing the code snippet, caret,
+/// underlines and FixItHint display as appropriate at each level. Walk is
+/// accomplished by calling itself recursively.
+///
+/// FIXME: Remove macro expansion from this routine, it shouldn't be tied to
+/// caret diagnostics.
+/// FIXME: Break up massive function into logical units.
+///
+/// \param Loc The location for this caret.
+/// \param Ranges The underlined ranges for this code snippet.
+/// \param Hints The FixIt hints active for this diagnostic.
+/// \param MacroSkipEnd The depth to stop skipping macro expansions.
+/// \param OnMacroInst The current depth of the macro expansion stack.
+void TextDiagnostic::EmitCaret(SourceLocation Loc,
+                               SmallVectorImpl<CharSourceRange>& Ranges,
+                               ArrayRef<FixItHint> Hints,
+                               unsigned &MacroDepth,
+                               unsigned OnMacroInst) {
+  assert(!Loc.isInvalid() && "must have a valid source location here");
+
+  // If this is a file source location, directly emit the source snippet and
+  // caret line. Also record the macro depth reached.
+  if (Loc.isFileID()) {
+    assert(MacroDepth == 0 && "We shouldn't hit a leaf node twice!");
+    MacroDepth = OnMacroInst;
+    EmitSnippetAndCaret(Loc, Ranges, Hints);
+    return;
+  }
+  // Otherwise recurse through each macro expansion layer.
+
+  // When processing macros, skip over the expansions leading up to
+  // a macro argument, and trace the argument's expansion stack instead.
+  Loc = skipToMacroArgExpansion(SM, Loc);
+
+  SourceLocation OneLevelUp = getImmediateMacroCallerLoc(SM, Loc);
+
+  // FIXME: Map ranges?
+  EmitCaret(OneLevelUp, Ranges, Hints, MacroDepth, OnMacroInst + 1);
+
+  // Map the location.
+  Loc = getImmediateMacroCalleeLoc(SM, Loc);
+
+  unsigned MacroSkipStart = 0, MacroSkipEnd = 0;
+  if (MacroDepth > DiagOpts.MacroBacktraceLimit) {
+    MacroSkipStart = DiagOpts.MacroBacktraceLimit / 2 +
+      DiagOpts.MacroBacktraceLimit % 2;
+    MacroSkipEnd = MacroDepth - DiagOpts.MacroBacktraceLimit / 2;
+  }
+
+  // Whether to suppress printing this macro expansion.
+  bool Suppressed = (OnMacroInst >= MacroSkipStart &&
+                     OnMacroInst < MacroSkipEnd);
+
+  // Map the ranges.
+  for (SmallVectorImpl<CharSourceRange>::iterator I = Ranges.begin(),
+                                                  E = Ranges.end();
+       I != E; ++I) {
+    SourceLocation Start = I->getBegin(), End = I->getEnd();
+    if (Start.isMacroID())
+      I->setBegin(getImmediateMacroCalleeLoc(SM, Start));
+    if (End.isMacroID())
+      I->setEnd(getImmediateMacroCalleeLoc(SM, End));
+  }
+
+  if (!Suppressed) {
+    // Don't print recursive expansion notes from an expansion note.
+    Loc = SM.getSpellingLoc(Loc);
+
+    // Get the pretty name, according to #line directives etc.
+    PresumedLoc PLoc = SM.getPresumedLoc(Loc);
+    if (PLoc.isInvalid())
+      return;
+
+    // If this diagnostic is not in the main file, print out the
+    // "included from" lines.
+    emitIncludeStack(PLoc.getIncludeLoc(), DiagnosticsEngine::Note);
+
+    if (DiagOpts.ShowLocation) {
+      // Emit the file/line/column that this expansion came from.
+      OS << PLoc.getFilename() << ':' << PLoc.getLine() << ':';
+      if (DiagOpts.ShowColumn)
+        OS << PLoc.getColumn() << ':';
+      OS << ' ';
+    }
+    OS << "note: expanded from:\n";
+
+    EmitSnippetAndCaret(Loc, Ranges, ArrayRef<FixItHint>());
+    return;
+  }
+
+  if (OnMacroInst == MacroSkipStart) {
+    // Tell the user that we've skipped contexts.
+    OS << "note: (skipping " << (MacroSkipEnd - MacroSkipStart) 
+    << " expansions in backtrace; use -fmacro-backtrace-limit=0 to see "
+    "all)\n";
+  }
+}
+
+/// \brief Emit a code snippet and caret line.
+///
+/// This routine emits a single line's code snippet and caret line..
+///
+/// \param Loc The location for the caret.
+/// \param Ranges The underlined ranges for this code snippet.
+/// \param Hints The FixIt hints active for this diagnostic.
+void TextDiagnostic::EmitSnippetAndCaret(
+    SourceLocation Loc,
+    SmallVectorImpl<CharSourceRange>& Ranges,
+    ArrayRef<FixItHint> Hints) {
+  assert(!Loc.isInvalid() && "must have a valid source location here");
+  assert(Loc.isFileID() && "must have a file location here");
+
+  // Decompose the location into a FID/Offset pair.
+  std::pair<FileID, unsigned> LocInfo = SM.getDecomposedLoc(Loc);
+  FileID FID = LocInfo.first;
+  unsigned FileOffset = LocInfo.second;
+
+  // Get information about the buffer it points into.
+  bool Invalid = false;
+  const char *BufStart = SM.getBufferData(FID, &Invalid).data();
+  if (Invalid)
+    return;
+
+  unsigned LineNo = SM.getLineNumber(FID, FileOffset);
+  unsigned ColNo = SM.getColumnNumber(FID, FileOffset);
+  unsigned CaretEndColNo
+    = ColNo + Lexer::MeasureTokenLength(Loc, SM, LangOpts);
+
+  // Rewind from the current position to the start of the line.
+  const char *TokPtr = BufStart+FileOffset;
+  const char *LineStart = TokPtr-ColNo+1; // Column # is 1-based.
+
+
+  // Compute the line end.  Scan forward from the error position to the end of
+  // the line.
+  const char *LineEnd = TokPtr;
+  while (*LineEnd != '\n' && *LineEnd != '\r' && *LineEnd != '\0')
+    ++LineEnd;
+
+  // FIXME: This shouldn't be necessary, but the CaretEndColNo can extend past
+  // the source line length as currently being computed. See
+  // test/Misc/message-length.c.
+  CaretEndColNo = std::min(CaretEndColNo, unsigned(LineEnd - LineStart));
+
+  // Copy the line of code into an std::string for ease of manipulation.
+  std::string SourceLine(LineStart, LineEnd);
+
+  // Create a line for the caret that is filled with spaces that is the same
+  // length as the line of source code.
+  std::string CaretLine(LineEnd-LineStart, ' ');
+
+  // Highlight all of the characters covered by Ranges with ~ characters.
+  for (SmallVectorImpl<CharSourceRange>::iterator I = Ranges.begin(),
+                                                  E = Ranges.end();
+       I != E; ++I)
+    HighlightRange(*I, LineNo, FID, SourceLine, CaretLine);
+
+  // Next, insert the caret itself.
+  if (ColNo-1 < CaretLine.size())
+    CaretLine[ColNo-1] = '^';
+  else
+    CaretLine.push_back('^');
+
+  ExpandTabs(SourceLine, CaretLine);
+
+  // If we are in -fdiagnostics-print-source-range-info mode, we are trying
+  // to produce easily machine parsable output.  Add a space before the
+  // source line and the caret to make it trivial to tell the main diagnostic
+  // line from what the user is intended to see.
+  if (DiagOpts.ShowSourceRanges) {
+    SourceLine = ' ' + SourceLine;
+    CaretLine = ' ' + CaretLine;
+  }
+
+  std::string FixItInsertionLine = BuildFixItInsertionLine(LineNo,
+                                                           LineStart, LineEnd,
+                                                           Hints);
+
+  // If the source line is too long for our terminal, select only the
+  // "interesting" source region within that line.
+  unsigned Columns = DiagOpts.MessageLength;
+  if (Columns && SourceLine.size() > Columns)
+    SelectInterestingSourceRegion(SourceLine, CaretLine, FixItInsertionLine,
+                                  CaretEndColNo, Columns);
+
+  // Finally, remove any blank spaces from the end of CaretLine.
+  while (CaretLine[CaretLine.size()-1] == ' ')
+    CaretLine.erase(CaretLine.end()-1);
+
+  // Emit what we have computed.
+  OS << SourceLine << '\n';
+
+  if (DiagOpts.ShowColors)
+    OS.changeColor(caretColor, true);
+  OS << CaretLine << '\n';
+  if (DiagOpts.ShowColors)
+    OS.resetColor();
+
+  if (!FixItInsertionLine.empty()) {
+    if (DiagOpts.ShowColors)
+      // Print fixit line in color
+      OS.changeColor(fixitColor, false);
+    if (DiagOpts.ShowSourceRanges)
+      OS << ' ';
+    OS << FixItInsertionLine << '\n';
+    if (DiagOpts.ShowColors)
+      OS.resetColor();
+  }
+
+  // Print out any parseable fixit information requested by the options.
+  EmitParseableFixits(Hints);
+}
+
+/*static*/ void
+TextDiagnostic::printDiagnosticLevel(raw_ostream &OS,
+                                     DiagnosticsEngine::Level Level,
+                                     bool ShowColors) {
+  if (ShowColors) {
+    // Print diagnostic category in bold and color
+    switch (Level) {
+    case DiagnosticsEngine::Ignored:
+      llvm_unreachable("Invalid diagnostic type");
+    case DiagnosticsEngine::Note:    OS.changeColor(noteColor, true); break;
+    case DiagnosticsEngine::Warning: OS.changeColor(warningColor, true); break;
+    case DiagnosticsEngine::Error:   OS.changeColor(errorColor, true); break;
+    case DiagnosticsEngine::Fatal:   OS.changeColor(fatalColor, true); break;
+    }
+  }
+
+  switch (Level) {
+  case DiagnosticsEngine::Ignored:
+    llvm_unreachable("Invalid diagnostic type");
+  case DiagnosticsEngine::Note:    OS << "note: "; break;
+  case DiagnosticsEngine::Warning: OS << "warning: "; break;
+  case DiagnosticsEngine::Error:   OS << "error: "; break;
+  case DiagnosticsEngine::Fatal:   OS << "fatal error: "; break;
+  }
+
+  if (ShowColors)
+    OS.resetColor();
+}
+
+/*static*/ void
+TextDiagnostic::printDiagnosticMessage(raw_ostream &OS,
+                                       DiagnosticsEngine::Level Level,
+                                       StringRef Message,
+                                       unsigned CurrentColumn, unsigned Columns,
+                                       bool ShowColors) {
+  if (ShowColors) {
+    // Print warnings, errors and fatal errors in bold, no color
+    switch (Level) {
+    case DiagnosticsEngine::Warning: OS.changeColor(savedColor, true); break;
+    case DiagnosticsEngine::Error:   OS.changeColor(savedColor, true); break;
+    case DiagnosticsEngine::Fatal:   OS.changeColor(savedColor, true); break;
+    default: break; //don't bold notes
+    }
+  }
+
+  if (Columns)
+    printWordWrapped(OS, Message, Columns, CurrentColumn);
+  else
+    OS << Messa