MFC 261991:

Upgrade our copy of llvm/clang to 3.4 release.  This version supports
all of the features in the current working draft of the upcoming C++
standard, provisionally named C++1y.

The code generator's performance is greatly increased, and the loop
auto-vectorizer is now enabled at -Os and -O2 in addition to -O3.  The
PowerPC backend has made several major improvements to code generation
quality and compile time, and the X86, SPARC, ARM32, Aarch64 and SystemZ
backends have all seen major feature work.

Release notes for llvm and clang can be found here:
<http://llvm.org/releases/3.4/docs/ReleaseNotes.html>
<http://llvm.org/releases/3.4/tools/clang/docs/ReleaseNotes.html>

MFC 262121 (by emaste):

Update lldb for clang/llvm 3.4 import

This commit largely restores the lldb source to the upstream r196259
snapshot with the addition of threaded inferior support and a few bug
fixes.

Specific upstream lldb revisions restored include:
   SVN      git
  181387  779e6ac
  181703  7bef4e2
  182099  b31044e
  182650  f2dcf35
  182683  0d91b80
  183862  15c1774
  183929  99447a6
  184177  0b2934b
  184948  4dc3761
  184954  007e7bc
  186990  eebd175

Sponsored by:	DARPA, AFRL

MFC 262186 (by emaste):

Fix mismerge in r262121

A break statement was lost in the merge.  The error had no functional
impact, but restore it to reduce the diff against upstream.

MFC 262303:

Pull in r197521 from upstream clang trunk (by rdivacky):

  Use the integrated assembler by default on FreeBSD/ppc and ppc64.

Requested by:	jhibbits

MFC 262611:

Pull in r196874 from upstream llvm trunk:

  Fix a crash that occurs when PWD is invalid.

  MCJIT needs to be able to run in hostile environments, even when PWD
  is invalid. There's no need to crash MCJIT in this case.

  The obvious fix is to simply leave MCContext's CompilationDir empty
  when PWD can't be determined. This way, MCJIT clients,
  and other clients that link with LLVM don't need a valid working directory.

  If we do want to guarantee valid CompilationDir, that should be done
  only for clients of getCompilationDir(). This is as simple as checking
  for an empty string.

  The only current use of getCompilationDir is EmitGenDwarfInfo, which
  won't conceivably run with an invalid working dir. However, in the
  purely hypothetically and untestable case that this happens, the
  AT_comp_dir will be omitted from the compilation_unit DIE.

This should help fix assertions occurring with ports-mgmt/tinderbox,
when it is using jails, and sometimes invalidates clang's current
working directory.

Reported by:	decke

MFC 262809:

Pull in r203007 from upstream clang trunk:

  Don't produce an alias between destructors with different calling conventions.

  Fixes pr19007.

(Please note that is an LLVM PR identifier, not a FreeBSD one.)

This should fix Firefox and/or libxul crashes (due to problems with
regparm/stdcall calling conventions) on i386.

Reported by:	multiple users on freebsd-current
PR:		bin/187103

MFC 263048:

Repair recognition of "CC" as an alias for the C++ compiler, since it
was silently broken by upstream for a Windows-specific use-case.

Apparently some versions of CMake still rely on this archaic feature...

Reported by:	rakuco

MFC 263049:

Garbage collect the old way of adding the libstdc++ include directories
in clang's InitHeaderSearch.cpp.  This has been superseded by David
Chisnall's commit in r255321.

Moreover, if libc++ is used, the libstdc++ include directories should
not be in the search path at all.  These directories are now only used
if you pass -stdlib=libstdc++.

1 files changed, 385 insertions, 119 deletions

diff --git a/contrib/llvm/tools/clang/lib/Format/BreakableToken.cpp b/contrib/llvm/tools/clang/lib/Format/BreakableToken.cpp
index 3e2e0ce..d720ce9 100644
--- a/contrib/llvm/tools/clang/lib/Format/BreakableToken.cpp
+++ b/contrib/llvm/tools/clang/lib/Format/BreakableToken.cpp
@@ -13,166 +13,432 @@
 ///
 //===----------------------------------------------------------------------===//
 
+#define DEBUG_TYPE "format-token-breaker"
+
 #include "BreakableToken.h"
+#include "clang/Basic/CharInfo.h"
+#include "clang/Format/Format.h"
 #include "llvm/ADT/STLExtras.h"
+#include "llvm/Support/Debug.h"
 #include <algorithm>
 
 namespace clang {
 namespace format {
 
-BreakableToken::Split BreakableComment::getSplit(unsigned LineIndex,
-                                                 unsigned TailOffset,
-                                                 unsigned ColumnLimit) const {
-  StringRef Text = getLine(LineIndex).substr(TailOffset);
-  unsigned ContentStartColumn = getContentStartColumn(LineIndex, TailOffset);
+static const char *const Blanks = " \t\v\f\r";
+static bool IsBlank(char C) {
+  switch (C) {
+  case ' ':
+  case '\t':
+  case '\v':
+  case '\f':
+  case '\r':
+    return true;
+  default:
+    return false;
+  }
+}
+
+static BreakableToken::Split getCommentSplit(StringRef Text,
+                                             unsigned ContentStartColumn,
+                                             unsigned ColumnLimit,
+                                             unsigned TabWidth,
+                                             encoding::Encoding Encoding) {
   if (ColumnLimit <= ContentStartColumn + 1)
-    return Split(StringRef::npos, 0);
+    return BreakableToken::Split(StringRef::npos, 0);
 
   unsigned MaxSplit = ColumnLimit - ContentStartColumn + 1;
-  StringRef::size_type SpaceOffset = Text.rfind(' ', MaxSplit);
+  unsigned MaxSplitBytes = 0;
+
+  for (unsigned NumChars = 0;
+       NumChars < MaxSplit && MaxSplitBytes < Text.size();) {
+    unsigned BytesInChar =
+        encoding::getCodePointNumBytes(Text[MaxSplitBytes], Encoding);
+    NumChars +=
+        encoding::columnWidthWithTabs(Text.substr(MaxSplitBytes, BytesInChar),
+                                      ContentStartColumn, TabWidth, Encoding);
+    MaxSplitBytes += BytesInChar;
+  }
+
+  StringRef::size_type SpaceOffset = Text.find_last_of(Blanks, MaxSplitBytes);
   if (SpaceOffset == StringRef::npos ||
-      Text.find_last_not_of(' ', SpaceOffset) == StringRef::npos) {
-    SpaceOffset = Text.find(' ', MaxSplit);
+      // Don't break at leading whitespace.
+      Text.find_last_not_of(Blanks, SpaceOffset) == StringRef::npos) {
+    // Make sure that we don't break at leading whitespace that
+    // reaches past MaxSplit.
+    StringRef::size_type FirstNonWhitespace = Text.find_first_not_of(Blanks);
+    if (FirstNonWhitespace == StringRef::npos)
+      // If the comment is only whitespace, we cannot split.
+      return BreakableToken::Split(StringRef::npos, 0);
+    SpaceOffset = Text.find_first_of(
+        Blanks, std::max<unsigned>(MaxSplitBytes, FirstNonWhitespace));
   }
   if (SpaceOffset != StringRef::npos && SpaceOffset != 0) {
-    StringRef BeforeCut = Text.substr(0, SpaceOffset).rtrim();
-    StringRef AfterCut = Text.substr(SpaceOffset).ltrim();
+    StringRef BeforeCut = Text.substr(0, SpaceOffset).rtrim(Blanks);
+    StringRef AfterCut = Text.substr(SpaceOffset).ltrim(Blanks);
     return BreakableToken::Split(BeforeCut.size(),
                                  AfterCut.begin() - BeforeCut.end());
   }
   return BreakableToken::Split(StringRef::npos, 0);
 }
 
-void BreakableComment::insertBreak(unsigned LineIndex, unsigned TailOffset,
-                                   Split Split, bool InPPDirective,
-                                   WhitespaceManager &Whitespaces) {
-  StringRef Text = getLine(LineIndex).substr(TailOffset);
-  StringRef AdditionalPrefix = Decoration;
-  if (Text.size() == Split.first + Split.second) {
-    // For all but the last line handle trailing space in trimLine.
-    if (LineIndex < Lines.size() - 1)
-      return;
-    // For the last line we need to break before "*/", but not to add "* ".
-    AdditionalPrefix = "";
+static BreakableToken::Split getStringSplit(StringRef Text,
+                                            unsigned UsedColumns,
+                                            unsigned ColumnLimit,
+                                            unsigned TabWidth,
+                                            encoding::Encoding Encoding) {
+  // FIXME: Reduce unit test case.
+  if (Text.empty())
+    return BreakableToken::Split(StringRef::npos, 0);
+  if (ColumnLimit <= UsedColumns)
+    return BreakableToken::Split(StringRef::npos, 0);
+  unsigned MaxSplit = std::min<unsigned>(
+      ColumnLimit - UsedColumns,
+      encoding::columnWidthWithTabs(Text, UsedColumns, TabWidth, Encoding) - 1);
+  StringRef::size_type SpaceOffset = 0;
+  StringRef::size_type SlashOffset = 0;
+  StringRef::size_type WordStartOffset = 0;
+  StringRef::size_type SplitPoint = 0;
+  for (unsigned Chars = 0;;) {
+    unsigned Advance;
+    if (Text[0] == '\\') {
+      Advance = encoding::getEscapeSequenceLength(Text);
+      Chars += Advance;
+    } else {
+      Advance = encoding::getCodePointNumBytes(Text[0], Encoding);
+      Chars += encoding::columnWidthWithTabs(
+          Text.substr(0, Advance), UsedColumns + Chars, TabWidth, Encoding);
+    }
+
+    if (Chars > MaxSplit)
+      break;
+
+    if (IsBlank(Text[0]))
+      SpaceOffset = SplitPoint;
+    if (Text[0] == '/')
+      SlashOffset = SplitPoint;
+    if (Advance == 1 && !isAlphanumeric(Text[0]))
+      WordStartOffset = SplitPoint;
+
+    SplitPoint += Advance;
+    Text = Text.substr(Advance);
   }
 
-  unsigned WhitespaceStartColumn =
-      getContentStartColumn(LineIndex, TailOffset) + Split.first;
-  unsigned BreakOffset = Text.data() - TokenText.data() + Split.first;
-  unsigned CharsToRemove = Split.second;
-  Whitespaces.breakToken(Tok, BreakOffset, CharsToRemove, "", AdditionalPrefix,
-                         InPPDirective, IndentAtLineBreak,
-                         WhitespaceStartColumn);
+  if (SpaceOffset != 0)
+    return BreakableToken::Split(SpaceOffset + 1, 0);
+  if (SlashOffset != 0)
+    return BreakableToken::Split(SlashOffset + 1, 0);
+  if (WordStartOffset != 0)
+    return BreakableToken::Split(WordStartOffset + 1, 0);
+  if (SplitPoint != 0)
+    return BreakableToken::Split(SplitPoint, 0);
+  return BreakableToken::Split(StringRef::npos, 0);
 }
 
-BreakableBlockComment::BreakableBlockComment(const SourceManager &SourceMgr,
-                                             const AnnotatedToken &Token,
-                                             unsigned StartColumn)
-    : BreakableComment(SourceMgr, Token.FormatTok, StartColumn + 2) {
-  assert(TokenText.startswith("/*") && TokenText.endswith("*/"));
+unsigned BreakableSingleLineToken::getLineCount() const { return 1; }
+
+unsigned BreakableSingleLineToken::getLineLengthAfterSplit(
+    unsigned LineIndex, unsigned Offset, StringRef::size_type Length) const {
+  return StartColumn + Prefix.size() + Postfix.size() +
+         encoding::columnWidthWithTabs(Line.substr(Offset, Length),
+                                       StartColumn + Prefix.size(),
+                                       Style.TabWidth, Encoding);
+}
+
+BreakableSingleLineToken::BreakableSingleLineToken(
+    const FormatToken &Tok, unsigned IndentLevel, unsigned StartColumn,
+    StringRef Prefix, StringRef Postfix, bool InPPDirective,
+    encoding::Encoding Encoding, const FormatStyle &Style)
+    : BreakableToken(Tok, IndentLevel, InPPDirective, Encoding, Style),
+      StartColumn(StartColumn), Prefix(Prefix), Postfix(Postfix) {
+  assert(Tok.TokenText.startswith(Prefix) && Tok.TokenText.endswith(Postfix));
+  Line = Tok.TokenText.substr(
+      Prefix.size(), Tok.TokenText.size() - Prefix.size() - Postfix.size());
+}
+
+BreakableStringLiteral::BreakableStringLiteral(
+    const FormatToken &Tok, unsigned IndentLevel, unsigned StartColumn,
+    StringRef Prefix, StringRef Postfix, bool InPPDirective,
+    encoding::Encoding Encoding, const FormatStyle &Style)
+    : BreakableSingleLineToken(Tok, IndentLevel, StartColumn, Prefix, Postfix,
+                               InPPDirective, Encoding, Style) {}
+
+BreakableToken::Split
+BreakableStringLiteral::getSplit(unsigned LineIndex, unsigned TailOffset,
+                                 unsigned ColumnLimit) const {
+  return getStringSplit(Line.substr(TailOffset),
+                        StartColumn + Prefix.size() + Postfix.size(),
+                        ColumnLimit, Style.TabWidth, Encoding);
+}
+
+void BreakableStringLiteral::insertBreak(unsigned LineIndex,
+                                         unsigned TailOffset, Split Split,
+                                         WhitespaceManager &Whitespaces) {
+  Whitespaces.replaceWhitespaceInToken(
+      Tok, Prefix.size() + TailOffset + Split.first, Split.second, Postfix,
+      Prefix, InPPDirective, 1, IndentLevel, StartColumn);
+}
+
+static StringRef getLineCommentPrefix(StringRef Comment) {
+  static const char *const KnownPrefixes[] = { "/// ", "///", "// ", "//" };
+  for (size_t i = 0, e = llvm::array_lengthof(KnownPrefixes); i != e; ++i)
+    if (Comment.startswith(KnownPrefixes[i]))
+      return KnownPrefixes[i];
+  return "";
+}
+
+BreakableLineComment::BreakableLineComment(
+    const FormatToken &Token, unsigned IndentLevel, unsigned StartColumn,
+    bool InPPDirective, encoding::Encoding Encoding, const FormatStyle &Style)
+    : BreakableSingleLineToken(Token, IndentLevel, StartColumn,
+                               getLineCommentPrefix(Token.TokenText), "",
+                               InPPDirective, Encoding, Style) {
+  OriginalPrefix = Prefix;
+  if (Token.TokenText.size() > Prefix.size() &&
+      isAlphanumeric(Token.TokenText[Prefix.size()])) {
+    if (Prefix == "//")
+      Prefix = "// ";
+    else if (Prefix == "///")
+      Prefix = "/// ";
+  }
+}
+
+BreakableToken::Split
+BreakableLineComment::getSplit(unsigned LineIndex, unsigned TailOffset,
+                               unsigned ColumnLimit) const {
+  return getCommentSplit(Line.substr(TailOffset), StartColumn + Prefix.size(),
+                         ColumnLimit, Style.TabWidth, Encoding);
+}
+
+void BreakableLineComment::insertBreak(unsigned LineIndex, unsigned TailOffset,
+                                       Split Split,
+                                       WhitespaceManager &Whitespaces) {
+  Whitespaces.replaceWhitespaceInToken(
+      Tok, OriginalPrefix.size() + TailOffset + Split.first, Split.second,
+      Postfix, Prefix, InPPDirective, /*Newlines=*/1, IndentLevel, StartColumn);
+}
+
+void BreakableLineComment::replaceWhitespace(unsigned LineIndex,
+                                             unsigned TailOffset, Split Split,
+                                             WhitespaceManager &Whitespaces) {
+  Whitespaces.replaceWhitespaceInToken(
+      Tok, OriginalPrefix.size() + TailOffset + Split.first, Split.second, "",
+      "", /*InPPDirective=*/false, /*Newlines=*/0, /*IndentLevel=*/0,
+      /*Spaces=*/1);
+}
 
-  OriginalStartColumn =
-      SourceMgr.getSpellingColumnNumber(Tok.getStartOfNonWhitespace()) - 1;
+void
+BreakableLineComment::replaceWhitespaceBefore(unsigned LineIndex,
+                                              WhitespaceManager &Whitespaces) {
+  if (OriginalPrefix != Prefix) {
+    Whitespaces.replaceWhitespaceInToken(Tok, OriginalPrefix.size(), 0, "", "",
+                                         /*InPPDirective=*/false,
+                                         /*Newlines=*/0, /*IndentLevel=*/0,
+                                         /*Spaces=*/1);
+  }
+}
 
+BreakableBlockComment::BreakableBlockComment(
+    const FormatToken &Token, unsigned IndentLevel, unsigned StartColumn,
+    unsigned OriginalStartColumn, bool FirstInLine, bool InPPDirective,
+    encoding::Encoding Encoding, const FormatStyle &Style)
+    : BreakableToken(Token, IndentLevel, InPPDirective, Encoding, Style) {
+  StringRef TokenText(Token.TokenText);
+  assert(TokenText.startswith("/*") && TokenText.endswith("*/"));
   TokenText.substr(2, TokenText.size() - 4).split(Lines, "\n");
 
-  bool NeedsStar = true;
-  CommonPrefixLength = UINT_MAX;
-  if (Lines.size() == 1) {
-    if (Token.Parent == 0) {
-      // Standalone block comments will be aligned and prefixed with *s.
-      CommonPrefixLength = OriginalStartColumn + 1;
-    } else {
-      // Trailing comments can start on arbitrary column, and available
-      // horizontal space can be too small to align consecutive lines with
-      // the first one. We could, probably, align them to current
-      // indentation level, but now we just wrap them without indentation
-      // and stars.
-      CommonPrefixLength = 0;
-      NeedsStar = false;
-    }
-  } else {
-    for (size_t i = 1; i < Lines.size(); ++i) {
-      size_t FirstNonWhitespace = Lines[i].find_first_not_of(" ");
-      if (FirstNonWhitespace != StringRef::npos) {
-        NeedsStar = NeedsStar && (Lines[i][FirstNonWhitespace] == '*');
-        CommonPrefixLength =
-            std::min<unsigned>(CommonPrefixLength, FirstNonWhitespace);
+  int IndentDelta = StartColumn - OriginalStartColumn;
+  LeadingWhitespace.resize(Lines.size());
+  StartOfLineColumn.resize(Lines.size());
+  StartOfLineColumn[0] = StartColumn + 2;
+  for (size_t i = 1; i < Lines.size(); ++i)
+    adjustWhitespace(i, IndentDelta);
+
+  Decoration = "* ";
+  if (Lines.size() == 1 && !FirstInLine) {
+    // Comments for which FirstInLine is false can start on arbitrary column,
+    // and available horizontal space can be too small to align consecutive
+    // lines with the first one.
+    // FIXME: We could, probably, align them to current indentation level, but
+    // now we just wrap them without stars.
+    Decoration = "";
+  }
+  for (size_t i = 1, e = Lines.size(); i < e && !Decoration.empty(); ++i) {
+    // If the last line is empty, the closing "*/" will have a star.
+    if (i + 1 == e && Lines[i].empty())
+      break;
+    while (!Lines[i].startswith(Decoration))
+      Decoration = Decoration.substr(0, Decoration.size() - 1);
+  }
+
+  LastLineNeedsDecoration = true;
+  IndentAtLineBreak = StartOfLineColumn[0] + 1;
+  for (size_t i = 1; i < Lines.size(); ++i) {
+    if (Lines[i].empty()) {
+      if (i + 1 == Lines.size()) {
+        // Empty last line means that we already have a star as a part of the
+        // trailing */. We also need to preserve whitespace, so that */ is
+        // correctly indented.
+        LastLineNeedsDecoration = false;
+      } else if (Decoration.empty()) {
+        // For all other lines, set the start column to 0 if they're empty, so
+        // we do not insert trailing whitespace anywhere.
+        StartOfLineColumn[i] = 0;
       }
+      continue;
     }
+    // The first line already excludes the star.
+    // For all other lines, adjust the line to exclude the star and
+    // (optionally) the first whitespace.
+    StartOfLineColumn[i] += Decoration.size();
+    Lines[i] = Lines[i].substr(Decoration.size());
+    LeadingWhitespace[i] += Decoration.size();
+    IndentAtLineBreak = std::min<int>(IndentAtLineBreak, StartOfLineColumn[i]);
   }
-  if (CommonPrefixLength == UINT_MAX)
-    CommonPrefixLength = 0;
+  IndentAtLineBreak = std::max<unsigned>(IndentAtLineBreak, Decoration.size());
+  DEBUG({
+    llvm::dbgs() << "IndentAtLineBreak " << IndentAtLineBreak << "\n";
+    for (size_t i = 0; i < Lines.size(); ++i) {
+      llvm::dbgs() << i << " |" << Lines[i] << "| " << LeadingWhitespace[i]
+                   << "\n";
+    }
+  });
+}
+
+void BreakableBlockComment::adjustWhitespace(unsigned LineIndex,
+                                             int IndentDelta) {
+  // When in a preprocessor directive, the trailing backslash in a block comment
+  // is not needed, but can serve a purpose of uniformity with necessary escaped
+  // newlines outside the comment. In this case we remove it here before
+  // trimming the trailing whitespace. The backslash will be re-added later when
+  // inserting a line break.
+  size_t EndOfPreviousLine = Lines[LineIndex - 1].size();
+  if (InPPDirective && Lines[LineIndex - 1].endswith("\\"))
+    --EndOfPreviousLine;
 
-  Decoration = NeedsStar ? "* " : "";
+  // Calculate the end of the non-whitespace text in the previous line.
+  EndOfPreviousLine =
+      Lines[LineIndex - 1].find_last_not_of(Blanks, EndOfPreviousLine);
+  if (EndOfPreviousLine == StringRef::npos)
+    EndOfPreviousLine = 0;
+  else
+    ++EndOfPreviousLine;
+  // Calculate the start of the non-whitespace text in the current line.
+  size_t StartOfLine = Lines[LineIndex].find_first_not_of(Blanks);
+  if (StartOfLine == StringRef::npos)
+    StartOfLine = Lines[LineIndex].size();
 
-  IndentAtLineBreak =
-      std::max<int>(StartColumn - OriginalStartColumn + CommonPrefixLength, 0);
+  StringRef Whitespace = Lines[LineIndex].substr(0, StartOfLine);
+  // Adjust Lines to only contain relevant text.
+  Lines[LineIndex - 1] = Lines[LineIndex - 1].substr(0, EndOfPreviousLine);
+  Lines[LineIndex] = Lines[LineIndex].substr(StartOfLine);
+  // Adjust LeadingWhitespace to account all whitespace between the lines
+  // to the current line.
+  LeadingWhitespace[LineIndex] =
+      Lines[LineIndex].begin() - Lines[LineIndex - 1].end();
+
+  // Adjust the start column uniformly accross all lines.
+  StartOfLineColumn[LineIndex] = std::max<int>(
+      0,
+      encoding::columnWidthWithTabs(Whitespace, 0, Style.TabWidth, Encoding) +
+          IndentDelta);
 }
 
-void BreakableBlockComment::alignLines(WhitespaceManager &Whitespaces) {
-  SourceLocation TokenLoc = Tok.getStartOfNonWhitespace();
-  int IndentDelta = (StartColumn - 2) - OriginalStartColumn;
-  if (IndentDelta > 0) {
-    std::string WhiteSpace(IndentDelta, ' ');
-    for (size_t i = 1; i < Lines.size(); ++i) {
-      Whitespaces.addReplacement(
-          TokenLoc.getLocWithOffset(Lines[i].data() - TokenText.data()), 0,
-          WhiteSpace);
-    }
-  } else if (IndentDelta < 0) {
-    std::string WhiteSpace(-IndentDelta, ' ');
-    // Check that the line is indented enough.
-    for (size_t i = 1; i < Lines.size(); ++i) {
-      if (!Lines[i].startswith(WhiteSpace))
-        return;
-    }
-    for (size_t i = 1; i < Lines.size(); ++i) {
-      Whitespaces.addReplacement(
-          TokenLoc.getLocWithOffset(Lines[i].data() - TokenText.data()),
-          -IndentDelta, "");
-    }
+unsigned BreakableBlockComment::getLineCount() const { return Lines.size(); }
+
+unsigned BreakableBlockComment::getLineLengthAfterSplit(
+    unsigned LineIndex, unsigned Offset, StringRef::size_type Length) const {
+  unsigned ContentStartColumn = getContentStartColumn(LineIndex, Offset);
+  return ContentStartColumn +
+         encoding::columnWidthWithTabs(Lines[LineIndex].substr(Offset, Length),
+                                       ContentStartColumn, Style.TabWidth,
+                                       Encoding) +
+         // The last line gets a "*/" postfix.
+         (LineIndex + 1 == Lines.size() ? 2 : 0);
+}
+
+BreakableToken::Split
+BreakableBlockComment::getSplit(unsigned LineIndex, unsigned TailOffset,
+                                unsigned ColumnLimit) const {
+  return getCommentSplit(Lines[LineIndex].substr(TailOffset),
+                         getContentStartColumn(LineIndex, TailOffset),
+                         ColumnLimit, Style.TabWidth, Encoding);
+}
+
+void BreakableBlockComment::insertBreak(unsigned LineIndex, unsigned TailOffset,
+                                        Split Split,
+                                        WhitespaceManager &Whitespaces) {
+  StringRef Text = Lines[LineIndex].substr(TailOffset);
+  StringRef Prefix = Decoration;
+  if (LineIndex + 1 == Lines.size() &&
+      Text.size() == Split.first + Split.second) {
+    // For the last line we need to break before "*/", but not to add "* ".
+    Prefix = "";
   }
 
-  for (unsigned i = 1; i < Lines.size(); ++i)
-    Lines[i] = Lines[i].substr(CommonPrefixLength + Decoration.size());
+  unsigned BreakOffsetInToken =
+      Text.data() - Tok.TokenText.data() + Split.first;
+  unsigned CharsToRemove = Split.second;
+  assert(IndentAtLineBreak >= Decoration.size());
+  Whitespaces.replaceWhitespaceInToken(
+      Tok, BreakOffsetInToken, CharsToRemove, "", Prefix, InPPDirective, 1,
+      IndentLevel, IndentAtLineBreak - Decoration.size());
 }
 
-void BreakableBlockComment::trimLine(unsigned LineIndex, unsigned TailOffset,
-                                     unsigned InPPDirective,
-                                     WhitespaceManager &Whitespaces) {
-  if (LineIndex == Lines.size() - 1)
-    return;
+void BreakableBlockComment::replaceWhitespace(unsigned LineIndex,
+                                              unsigned TailOffset, Split Split,
+                                              WhitespaceManager &Whitespaces) {
   StringRef Text = Lines[LineIndex].substr(TailOffset);
-  if (!Text.endswith(" ") && !InPPDirective)
+  unsigned BreakOffsetInToken =
+      Text.data() - Tok.TokenText.data() + Split.first;
+  unsigned CharsToRemove = Split.second;
+  Whitespaces.replaceWhitespaceInToken(
+      Tok, BreakOffsetInToken, CharsToRemove, "", "", /*InPPDirective=*/false,
+      /*Newlines=*/0, /*IndentLevel=*/0, /*Spaces=*/1);
+}
+
+void
+BreakableBlockComment::replaceWhitespaceBefore(unsigned LineIndex,
+                                               WhitespaceManager &Whitespaces) {
+  if (LineIndex == 0)
     return;
+  StringRef Prefix = Decoration;
+  if (Lines[LineIndex].empty()) {
+    if (LineIndex + 1 == Lines.size()) {
+      if (!LastLineNeedsDecoration) {
+        // If the last line was empty, we don't need a prefix, as the */ will
+        // line up with the decoration (if it exists).
+        Prefix = "";
+      }
+    } else if (!Decoration.empty()) {
+      // For other empty lines, if we do have a decoration, adapt it to not
+      // contain a trailing whitespace.
+      Prefix = Prefix.substr(0, 1);
+    }
+  } else {
+    if (StartOfLineColumn[LineIndex] == 1) {
+      // This line starts immediately after the decorating *.
+      Prefix = Prefix.substr(0, 1);
+    }
+  }
 
-  StringRef TrimmedLine = Text.rtrim();
-  unsigned WhitespaceStartColumn =
-      getLineLengthAfterSplit(LineIndex, TailOffset);
-  unsigned BreakOffset = TrimmedLine.end() - TokenText.data();
-  unsigned CharsToRemove = Text.size() - TrimmedLine.size() + 1;
-  Whitespaces.breakToken(Tok, BreakOffset, CharsToRemove, "", "", InPPDirective,
-                         0, WhitespaceStartColumn);
-}
-
-BreakableLineComment::BreakableLineComment(const SourceManager &SourceMgr,
-                                           const AnnotatedToken &Token,
-                                           unsigned StartColumn)
-    : BreakableComment(SourceMgr, Token.FormatTok, StartColumn) {
-  assert(TokenText.startswith("//"));
-  Decoration = getLineCommentPrefix(TokenText);
-  Lines.push_back(TokenText.substr(Decoration.size()));
-  IndentAtLineBreak = StartColumn;
-  this->StartColumn += Decoration.size(); // Start column of the contents.
-}
-
-StringRef BreakableLineComment::getLineCommentPrefix(StringRef Comment) {
-  const char *KnownPrefixes[] = { "/// ", "///", "// ", "//" };
-  for (size_t i = 0; i < llvm::array_lengthof(KnownPrefixes); ++i)
-    if (Comment.startswith(KnownPrefixes[i]))
-      return KnownPrefixes[i];
-  return "";
+  unsigned WhitespaceOffsetInToken = Lines[LineIndex].data() -
+                                     Tok.TokenText.data() -
+                                     LeadingWhitespace[LineIndex];
+  assert(StartOfLineColumn[LineIndex] >= Prefix.size());
+  Whitespaces.replaceWhitespaceInToken(
+      Tok, WhitespaceOffsetInToken, LeadingWhitespace[LineIndex], "", Prefix,
+      InPPDirective, 1, IndentLevel,
+      StartOfLineColumn[LineIndex] - Prefix.size());
+}
+
+unsigned
+BreakableBlockComment::getContentStartColumn(unsigned LineIndex,
+                                             unsigned TailOffset) const {
+  // If we break, we always break at the predefined indent.
+  if (TailOffset != 0)
+    return IndentAtLineBreak;
+  return StartOfLineColumn[LineIndex];
 }
 
 } // namespace format