TextDiagnostic.cpp

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//===--- TextDiagnostic.cpp - Text Diagnostic Pretty-Printing -------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
 
#include "clang/Frontend/TextDiagnostic.h"
#include "clang/Basic/CharInfo.h"
#include "clang/Basic/DiagnosticOptions.h"
#include "clang/Basic/FileManager.h"
#include "clang/Basic/SourceManager.h"
#include "clang/Lex/Lexer.h"
#include "clang/Lex/Preprocessor.h"
#include "llvm/ADT/SmallString.h"
#include "llvm/ADT/StringExtras.h"
#include "llvm/Support/ConvertUTF.h"
#include "llvm/Support/ErrorHandling.h"
#include "llvm/Support/Locale.h"
#include "llvm/Support/Path.h"
#include "llvm/Support/raw_ostream.h"
#include <algorithm>
#include <optional>
 
using namespace clang;
 
static const enum raw_ostream::Colors noteColor = raw_ostream::CYAN;
static const enum raw_ostream::Colors remarkColor =
  raw_ostream::BLUE;
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 templateColor =
  raw_ostream::CYAN;
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;
 
// Magenta is taken for 'warning'. Red is already 'error' and 'cyan'
// is already taken for 'note'. Green is already used to underline
// source ranges. White and black are bad because of the usual
// terminal backgrounds. Which leaves us only with TWO options.
static constexpr raw_ostream::Colors CommentColor = raw_ostream::YELLOW;
static constexpr raw_ostream::Colors LiteralColor = raw_ostream::GREEN;
static constexpr raw_ostream::Colors KeywordColor = raw_ostream::BLUE;
 
/// Add highlights to differences in template strings.
static void applyTemplateHighlighting(raw_ostream &OS, StringRef Str,
                                      bool &Normal, bool Bold) {
  while (true) {
    size_t Pos = Str.find(ToggleHighlight);
    OS << Str.slice(0, Pos);
    if (Pos == StringRef::npos)
      break;
 
    Str = Str.substr(Pos + 1);
    if (Normal)
      OS.changeColor(templateColor, true);
    else {
      OS.resetColor();
      if (Bold)
        OS.changeColor(savedColor, true);
    }
    Normal = !Normal;
  }
}
 
/// Number of spaces to indent when word-wrapping.
const unsigned WordWrapIndentation = 6;
 
static int bytesSincePreviousTabOrLineBegin(StringRef SourceLine, size_t i) {
  int bytes = 0;
  while (0<i) {
    if (SourceLine[--i]=='\t')
      break;
    ++bytes;
  }
  return bytes;
}
 
/// returns a printable representation of first item from input range
///
/// This function returns a printable representation of the next item in a line
///  of source. If the next byte begins a valid and printable character, that
///  character is returned along with 'true'.
///
/// Otherwise, if the next byte begins a valid, but unprintable character, a
///  printable, escaped representation of the character is returned, along with
///  'false'. Otherwise a printable, escaped representation of the next byte
///  is returned along with 'false'.
///
/// \note The index is updated to be used with a subsequent call to
///        printableTextForNextCharacter.
///
/// \param SourceLine The line of source
/// \param I Pointer to byte index,
/// \param TabStop used to expand tabs
/// \return pair(printable text, 'true' iff original text was printable)
///
static std::pair<SmallString<16>, bool>
printableTextForNextCharacter(StringRef SourceLine, size_t *I,
                              unsigned TabStop) {
  assert(I && "I must not be null");
  assert(*I < SourceLine.size() && "must point to a valid index");
 
  if (SourceLine[*I] == '\t') {
    assert(0 < TabStop && TabStop <= DiagnosticOptions::MaxTabStop &&
           "Invalid -ftabstop value");
    unsigned Col = bytesSincePreviousTabOrLineBegin(SourceLine, *I);
    unsigned NumSpaces = TabStop - (Col % TabStop);
    assert(0 < NumSpaces && NumSpaces <= TabStop
           && "Invalid computation of space amt");
    ++(*I);
 
    SmallString<16> ExpandedTab;
    ExpandedTab.assign(NumSpaces, ' ');
    return std::make_pair(ExpandedTab, true);
  }
 
  const unsigned char *Begin = SourceLine.bytes_begin() + *I;
 
  // Fast path for the common ASCII case.
  if (*Begin < 0x80 && llvm::sys::locale::isPrint(*Begin)) {
    ++(*I);
    return std::make_pair(SmallString<16>(Begin, Begin + 1), true);
  }
  unsigned CharSize = llvm::getNumBytesForUTF8(*Begin);
  const unsigned char *End = Begin + CharSize;
 
  // Convert it to UTF32 and check if it's printable.
  if (End <= SourceLine.bytes_end() && llvm::isLegalUTF8Sequence(Begin, End)) {
    llvm::UTF32 C;
    llvm::UTF32 *CPtr = &C;
 
    // Begin and end before conversion.
    unsigned char const *OriginalBegin = Begin;
    llvm::ConversionResult Res = llvm::ConvertUTF8toUTF32(
        &Begin, End, &CPtr, CPtr + 1, llvm::strictConversion);
    (void)Res;
    assert(Res == llvm::conversionOK);
    assert(OriginalBegin < Begin);
    assert(unsigned(Begin - OriginalBegin) == CharSize);
 
    (*I) += (Begin - OriginalBegin);
 
    // Valid, multi-byte, printable UTF8 character.
    if (llvm::sys::locale::isPrint(C))
      return std::make_pair(SmallString<16>(OriginalBegin, End), true);
 
    // Valid but not printable.
    SmallString<16> Str("<U+>");
    while (C) {
      Str.insert(Str.begin() + 3, llvm::hexdigit(C % 16));
      C /= 16;
    }
    while (Str.size() < 8)
      Str.insert(Str.begin() + 3, llvm::hexdigit(0));
    return std::make_pair(Str, false);
  }
 
  // Otherwise, not printable since it's not valid UTF8.
  SmallString<16> ExpandedByte("<XX>");
  unsigned char Byte = SourceLine[*I];
  ExpandedByte[1] = llvm::hexdigit(Byte / 16);
  ExpandedByte[2] = llvm::hexdigit(Byte % 16);
  ++(*I);
  return std::make_pair(ExpandedByte, false);
}
 
static void expandTabs(std::string &SourceLine, unsigned TabStop) {
  size_t I = SourceLine.size();
  while (I > 0) {
    I--;
    if (SourceLine[I] != '\t')
      continue;
    size_t TmpI = I;
    auto [Str, Printable] =
        printableTextForNextCharacter(SourceLine, &TmpI, TabStop);
    SourceLine.replace(I, 1, Str.c_str());
  }
}
 
/// \p BytesOut:
///  A mapping from columns to the byte of the source line that produced the
///  character displaying at that column. This is the inverse of \p ColumnsOut.
///
/// The last element in the array is the number of bytes in the source string.
///
/// example: (given a tabstop of 8)
///
///    "a \t \u3042" -> {0,1,2,-1,-1,-1,-1,-1,3,4,-1,7}
///
///  (\\u3042 is represented in UTF-8 by three bytes and takes two columns to
///   display)
///
/// \p ColumnsOut:
///  A mapping from the bytes
///  of the printable representation of the line to the columns those printable
///  characters will appear at (numbering the first column as 0).
///
/// If a byte 'i' corresponds to multiple columns (e.g. the byte contains a tab
///  character) then the array will map that byte to the first column the
///  tab appears at and the next value in the map will have been incremented
///  more than once.
///
/// If a byte is the first in a sequence of bytes that together map to a single
///  entity in the output, then the array will map that byte to the appropriate
///  column while the subsequent bytes will be -1.
///
/// The last element in the array does not correspond to any byte in the input
///  and instead is the number of columns needed to display the source
///
/// example: (given a tabstop of 8)
///
///    "a \t \u3042" -> {0,1,2,8,9,-1,-1,11}
///
///  (\\u3042 is represented in UTF-8 by three bytes and takes two columns to
///   display)
static void genColumnByteMapping(StringRef SourceLine, unsigned TabStop,
                                 SmallVectorImpl<int> &BytesOut,
                                 SmallVectorImpl<int> &ColumnsOut) {
  assert(BytesOut.empty());
  assert(ColumnsOut.empty());
 
  if (SourceLine.empty()) {
    BytesOut.resize(1u, 0);
    ColumnsOut.resize(1u, 0);
    return;
  }
 
  ColumnsOut.resize(SourceLine.size() + 1, -1);
 
  int Columns = 0;
  size_t I = 0;
  while (I < SourceLine.size()) {
    ColumnsOut[I] = Columns;
    BytesOut.resize(Columns + 1, -1);
    BytesOut.back() = I;
    auto [Str, Printable] =
        printableTextForNextCharacter(SourceLine, &I, TabStop);
    Columns += llvm::sys::locale::columnWidth(Str);
  }
 
  ColumnsOut.back() = Columns;
  BytesOut.resize(Columns + 1, -1);
  BytesOut.back() = I;
}
 
namespace {
struct SourceColumnMap {
  SourceColumnMap(StringRef SourceLine, unsigned TabStop)
  : m_SourceLine(SourceLine) {
 
    genColumnByteMapping(SourceLine, TabStop, m_columnToByte, m_byteToColumn);
 
    assert(m_byteToColumn.size()==SourceLine.size()+1);
    assert(0 < m_byteToColumn.size() && 0 < m_columnToByte.size());
    assert(m_byteToColumn.size()
           == static_cast<unsigned>(m_columnToByte.back()+1));
    assert(static_cast<unsigned>(m_byteToColumn.back()+1)
           == m_columnToByte.size());
  }
  int columns() const { return m_byteToColumn.back(); }
  int bytes() const { return m_columnToByte.back(); }
 
  /// Map a byte to the column which it is at the start of, or return -1
  /// if it is not at the start of a column (for a UTF-8 trailing byte).
  int byteToColumn(int n) const {
    assert(0<=n && n<static_cast<int>(m_byteToColumn.size()));
    return m_byteToColumn[n];
  }
 
  /// Map a byte to the first column which contains it.
  int byteToContainingColumn(int N) const {
    assert(0 <= N && N < static_cast<int>(m_byteToColumn.size()));
    while (m_byteToColumn[N] == -1)
      --N;
    return m_byteToColumn[N];
  }
 
  /// Map a column to the byte which starts the column, or return -1 if
  /// the column the second or subsequent column of an expanded tab or similar
  /// multi-column entity.
  int columnToByte(int n) const {
    assert(0<=n && n<static_cast<int>(m_columnToByte.size()));
    return m_columnToByte[n];
  }
 
  /// Map from a byte index to the next byte which starts a column.
  int startOfNextColumn(int N) const {
    assert(0 <= N && N < static_cast<int>(m_byteToColumn.size() - 1));
    while (byteToColumn(++N) == -1) {}
    return N;
  }
 
  /// Map from a byte index to the previous byte which starts a column.
  int startOfPreviousColumn(int N) const {
    assert(0 < N && N < static_cast<int>(m_byteToColumn.size()));
    while (byteToColumn(--N) == -1) {}
    return N;
  }
 
  StringRef getSourceLine() const {
    return m_SourceLine;
  }
 
private:
  const std::string m_SourceLine;
  SmallVector<int,200> m_byteToColumn;
  SmallVector<int,200> m_columnToByte;
};
} // end anonymous namespace
 
/// 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 Columns,
                                          const SourceColumnMap &map) {
  unsigned CaretColumns = CaretLine.size();
  unsigned FixItColumns = llvm::sys::locale::columnWidth(FixItInsertionLine);
  unsigned MaxColumns = std::max(static_cast<unsigned>(map.columns()),
                                 std::max(CaretColumns, FixItColumns));
  // if the number of columns is less than the desired number we're done
  if (MaxColumns <= Columns)
    return;
 
  // No special characters are allowed in CaretLine.
  assert(llvm::none_of(CaretLine, [](char c) { return c < ' ' || '~' < c; }));
 
  // Find the slice that we need to display the full caret line
  // correctly.
  unsigned CaretStart = 0, CaretEnd = CaretLine.size();
  for (; CaretStart != CaretEnd; ++CaretStart)
    if (!isWhitespace(CaretLine[CaretStart]))
      break;
 
  for (; CaretEnd != CaretStart; --CaretEnd)
    if (!isWhitespace(CaretLine[CaretEnd - 1]))
      break;
 
  // caret has already been inserted into CaretLine so the above whitespace
  // check is guaranteed to include the caret
 
  // 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 (!isWhitespace(FixItInsertionLine[FixItStart]))
        break;
 
    for (; FixItEnd != FixItStart; --FixItEnd)
      if (!isWhitespace(FixItInsertionLine[FixItEnd - 1]))
        break;
 
    // We can safely use the byte offset FixItStart as the column offset
    // because the characters up until FixItStart are all ASCII whitespace
    // characters.
    unsigned FixItStartCol = FixItStart;
    unsigned FixItEndCol
      = llvm::sys::locale::columnWidth(FixItInsertionLine.substr(0, FixItEnd));
 
    CaretStart = std::min(FixItStartCol, CaretStart);
    CaretEnd = std::max(FixItEndCol, CaretEnd);
  }
 
  // CaretEnd may have been set at the middle of a character
  // If it's not at a character's first column then advance it past the current
  //   character.
  while (static_cast<int>(CaretEnd) < map.columns() &&
         -1 == map.columnToByte(CaretEnd))
    ++CaretEnd;
 
  assert((static_cast<int>(CaretStart) > map.columns() ||
          -1!=map.columnToByte(CaretStart)) &&
         "CaretStart must not point to a column in the middle of a source"
         " line character");
  assert((static_cast<int>(CaretEnd) > map.columns() ||
          -1!=map.columnToByte(CaretEnd)) &&
         "CaretEnd must not point to a column in the middle of a source line"
         " character");
 
  // 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.
 
  unsigned SourceStart = map.columnToByte(std::min<unsigned>(CaretStart,
                                                             map.columns()));
  unsigned SourceEnd = map.columnToByte(std::min<unsigned>(CaretEnd,
                                                           map.columns()));
 
  unsigned CaretColumnsOutsideSource = CaretEnd-CaretStart
    - (map.byteToColumn(SourceEnd)-map.byteToColumn(SourceStart));
 
  char const *front_ellipse = "  ...";
  char const *front_space   = "     ";
  char const *back_ellipse = "...";
  unsigned ellipses_space = strlen(front_ellipse) + strlen(back_ellipse);
 
  unsigned TargetColumns = Columns;
  // Give us extra room for the ellipses
  //  and any of the caret line that extends past the source
  if (TargetColumns > ellipses_space+CaretColumnsOutsideSource)
    TargetColumns -= ellipses_space+CaretColumnsOutsideSource;
 
  while (SourceStart>0 || SourceEnd<SourceLine.size()) {
    bool ExpandedRegion = false;
 
    if (SourceStart>0) {
      unsigned NewStart = map.startOfPreviousColumn(SourceStart);
 
      // Skip over any whitespace we see here; we're looking for
      // another bit of interesting text.
      // FIXME: Detect non-ASCII whitespace characters too.
      while (NewStart && isWhitespace(SourceLine[NewStart]))
        NewStart = map.startOfPreviousColumn(NewStart);
 
      // Skip over this bit of "interesting" text.
      while (NewStart) {
        unsigned Prev = map.startOfPreviousColumn(NewStart);
        if (isWhitespace(SourceLine[Prev]))
          break;
        NewStart = Prev;
      }
 
      assert(map.byteToColumn(NewStart) != -1);
      unsigned NewColumns = map.byteToColumn(SourceEnd) -
                              map.byteToColumn(NewStart);
      if (NewColumns <= TargetColumns) {
        SourceStart = NewStart;
        ExpandedRegion = true;
      }
    }
 
    if (SourceEnd<SourceLine.size()) {
      unsigned NewEnd = map.startOfNextColumn(SourceEnd);
 
      // Skip over any whitespace we see here; we're looking for
      // another bit of interesting text.
      // FIXME: Detect non-ASCII whitespace characters too.
      while (NewEnd < SourceLine.size() && isWhitespace(SourceLine[NewEnd]))
        NewEnd = map.startOfNextColumn(NewEnd);
 
      // Skip over this bit of "interesting" text.
      while (NewEnd < SourceLine.size() && isWhitespace(SourceLine[NewEnd]))
        NewEnd = map.startOfNextColumn(NewEnd);
 
      assert(map.byteToColumn(NewEnd) != -1);
      unsigned NewColumns = map.byteToColumn(NewEnd) -
                              map.byteToColumn(SourceStart);
      if (NewColumns <= TargetColumns) {
        SourceEnd = NewEnd;
        ExpandedRegion = true;
      }
    }
 
    if (!ExpandedRegion)
      break;
  }
 
  CaretStart = map.byteToColumn(SourceStart);
  CaretEnd = map.byteToColumn(SourceEnd) + CaretColumnsOutsideSource;
 
  // [CaretStart, CaretEnd) is the slice we want. Update the various
  // output lines to show only this slice.
  assert(CaretStart!=(unsigned)-1 && CaretEnd!=(unsigned)-1 &&
         SourceStart!=(unsigned)-1 && SourceEnd!=(unsigned)-1);
  assert(SourceStart <= SourceEnd);
  assert(CaretStart <= CaretEnd);
 
  unsigned BackColumnsRemoved
    = map.byteToColumn(SourceLine.size())-map.byteToColumn(SourceEnd);
  unsigned FrontColumnsRemoved = CaretStart;
  unsigned ColumnsKept = CaretEnd-CaretStart;
 
  // We checked up front that the line needed truncation
  assert(FrontColumnsRemoved+ColumnsKept+BackColumnsRemoved > Columns);
 
  // The line needs some truncation, and we'd prefer to keep the front
  //  if possible, so remove the back
  if (BackColumnsRemoved > strlen(back_ellipse))
    SourceLine.replace(SourceEnd, std::string::npos, back_ellipse);
 
  // If that's enough then we're done
  if (FrontColumnsRemoved+ColumnsKept <= Columns)
    return;
 
  // Otherwise remove the front as well
  if (FrontColumnsRemoved > strlen(front_ellipse)) {
    SourceLine.replace(0, SourceStart, front_ellipse);
    CaretLine.replace(0, CaretStart, front_space);
    if (!FixItInsertionLine.empty())
      FixItInsertionLine.replace(0, CaretStart, front_space);
  }
}
 
/// 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 && isWhitespace(Str[Idx]))
    ++Idx;
  return Idx;
}
 
/// 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;
}
 
/// 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 && !isWhitespace(Str[End]))
      ++End;
    return End;
  }
 
  // We have the start of a balanced punctuation sequence (quotes,
  // parentheses, etc.). Determine the full sequence is.
  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 && !isWhitespace(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);
}
 
/// 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 Bold if the current text should be bold
/// \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, bool Bold) {
  const unsigned Length = std::min(Str.find('\n'), Str.size());
  bool TextNormal = true;
 
  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;
      }
      applyTemplateHighlighting(OS, Str.substr(WordStart, WordLength),
                                TextNormal, Bold);
      Column += WordLength;
      continue;
    }
 
    // This word does not fit on the current line, so wrap to the next
    // line.
    OS << '\n';
    OS.indent(WordWrapIndentation);
    applyTemplateHighlighting(OS, Str.substr(WordStart, WordLength),
                              TextNormal, Bold);
    Column = WordWrapIndentation + WordLength;
    Wrapped = true;
  }
 
  // Append any remaning text from the message with its existing formatting.
  applyTemplateHighlighting(OS, Str.substr(Length), TextNormal, Bold);
 
  assert(TextNormal && "Text highlighted at end of diagnostic message.");
 
  return Wrapped;
}
 
TextDiagnostic::TextDiagnostic(raw_ostream &OS, const LangOptions &LangOpts,
                               DiagnosticOptions *DiagOpts,
                               const Preprocessor *PP)
    : DiagnosticRenderer(LangOpts, DiagOpts), OS(OS), PP(PP) {}
 
TextDiagnostic::~TextDiagnostic() {}
 
void TextDiagnostic::emitDiagnosticMessage(
    FullSourceLoc Loc, PresumedLoc PLoc, DiagnosticsEngine::Level Level,
    StringRef Message, ArrayRef<clang::CharSourceRange> Ranges,
    DiagOrStoredDiag D) {
  uint64_t StartOfLocationInfo = OS.tell();
 
  // Emit the location of this particular diagnostic.
  if (Loc.isValid())
    emitDiagnosticLoc(Loc, PLoc, Level, Ranges);
 
  if (DiagOpts->ShowColors)
    OS.resetColor();
 
  if (DiagOpts->ShowLevel)
    printDiagnosticLevel(OS, Level, DiagOpts->ShowColors);
  printDiagnosticMessage(OS,
                         /*IsSupplemental*/ Level == DiagnosticsEngine::Note,
                         Message, OS.tell() - StartOfLocationInfo,
                         DiagOpts->MessageLength, DiagOpts->ShowColors);
}
 
/*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::Remark:  OS.changeColor(remarkColor, 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::Remark:  OS << "remark: "; 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,
                                            bool IsSupplemental,
                                            StringRef Message,
                                            unsigned CurrentColumn,
                                            unsigned Columns, bool ShowColors) {
  bool Bold = false;
  if (ShowColors && !IsSupplemental) {
    // Print primary diagnostic messages in bold and without color, to visually
    // indicate the transition from continuation notes and other output.
    OS.changeColor(savedColor, true);
    Bold = true;
  }
 
  if (Columns)
    printWordWrapped(OS, Message, Columns, CurrentColumn, Bold);
  else {
    bool Normal = true;
    applyTemplateHighlighting(OS, Message, Normal, Bold);
    assert(Normal && "Formatting should have returned to normal");
  }
 
  if (ShowColors)
    OS.resetColor();
  OS << '\n';
}
 
void TextDiagnostic::emitFilename(StringRef Filename, const SourceManager &SM) {
#ifdef _WIN32
  SmallString<4096> TmpFilename;
#endif
  if (DiagOpts->AbsolutePath) {
    auto File = SM.getFileManager().getOptionalFileRef(Filename);
    if (File) {
      // We want to print a simplified absolute path, i. e. without "dots".
      //
      // The hardest part here are the paths like "<part1>/<link>/../<part2>".
      // On Unix-like systems, we cannot just collapse "<link>/..", because
      // paths are resolved sequentially, and, thereby, the path
      // "<part1>/<part2>" may point to a different location. That is why
      // we use FileManager::getCanonicalName(), which expands all indirections
      // with llvm::sys::fs::real_path() and caches the result.
      //
      // On the other hand, it would be better to preserve as much of the
      // original path as possible, because that helps a user to recognize it.
      // real_path() expands all links, which sometimes too much. Luckily,
      // on Windows we can just use llvm::sys::path::remove_dots(), because,
      // on that system, both aforementioned paths point to the same place.
#ifdef _WIN32
      TmpFilename = File->getName();
      llvm::sys::fs::make_absolute(TmpFilename);
      llvm::sys::path::native(TmpFilename);
      llvm::sys::path::remove_dots(TmpFilename, /* remove_dot_dot */ true);
      Filename = StringRef(TmpFilename.data(), TmpFilename.size());
#else
      Filename = SM.getFileManager().getCanonicalName(*File);
#endif
    }
  }
 
  OS << Filename;
}
 
/// Print out the file/line/column information and include trace.
///
/// This method handles the emission of the diagnostic location information.
/// This includes extracting as much location information as is present for
/// the diagnostic and printing it, as well as any include stack or source
/// ranges necessary.
void TextDiagnostic::emitDiagnosticLoc(FullSourceLoc Loc, PresumedLoc PLoc,
                                       DiagnosticsEngine::Level Level,
                                       ArrayRef<CharSourceRange> Ranges) {
  if (PLoc.isInvalid()) {
    // At least print the file name if available:
    if (FileID FID = Loc.getFileID(); FID.isValid()) {
      if (OptionalFileEntryRef FE = Loc.getFileEntryRef()) {
        emitFilename(FE->getName(), Loc.getManager());
        OS << ": ";
      }
    }
    return;
  }
  unsigned LineNo = PLoc.getLine();
 
  if (!DiagOpts->ShowLocation)
    return;
 
  if (DiagOpts->ShowColors)
    OS.changeColor(