Merge clang, llvm, lld, lldb, compiler-rt and libc++ 5.0.0 release.

MFC r309126 (by emaste):

  Correct lld llvm-tblgen dependency file name

MFC r309169:

  Get rid of separate Subversion mergeinfo properties for llvm-dwarfdump
  and llvm-lto.  The mergeinfo confuses Subversion enormously, and these
  directories will just use the mergeinfo for llvm itself.

MFC r312765:

  Pull in r276136 from upstream llvm trunk (by Wei Mi):

    Use ValueOffsetPair to enhance value reuse during SCEV expansion.

    In D12090, the ExprValueMap was added to reuse existing value during
    SCEV expansion. However, const folding and sext/zext distribution can
    make the reuse still difficult.

    A simplified case is: suppose we know S1 expands to V1 in
    ExprValueMap, and
      S1 = S2 + C_a
      S3 = S2 + C_b
    where C_a and C_b are different SCEVConstants. Then we'd like to
    expand S3 as V1 - C_a + C_b instead of expanding S2 literally. It is
    helpful when S2 is a complex SCEV expr and S2 has no entry in
    ExprValueMap, which is usually caused by the fact that S3 is
    generated from S1 after const folding.

    In order to do that, we represent ExprValueMap as a mapping from SCEV
    to ValueOffsetPair. We will save both S1->{V1, 0} and S2->{V1, C_a}
    into the ExprValueMap when we create SCEV for V1. When S3 is
    expanded, it will first expand S2 to V1 - C_a because of S2->{V1,
    C_a} in the map, then expand S3 to V1 - C_a + C_b.

    Differential Revision: https://reviews.llvm.org/D21313

  This should fix assertion failures when building OpenCV >= 3.1.

  PR:		215649

MFC r312831:

  Revert r312765 for now, since it causes assertions when building
  lang/spidermonkey24.

  Reported by:	antoine
  PR:		215649

MFC r316511 (by jhb):

  Add an implementation of __ffssi2() derived from __ffsdi2().

  Newer versions of GCC include an __ffssi2() symbol in libgcc and the
  compiler can emit calls to it in generated code.  This is true for at
  least GCC 6.2 when compiling world for mips and mips64.

  Reviewed by:	jmallett, dim
  Sponsored by:	DARPA / AFRL
  Differential Revision:	https://reviews.freebsd.org/D10086

MFC r318601 (by adrian):

  [libcompiler-rt] add bswapdi2/bswapsi2

  This is required for mips gcc 6.3 userland to build/run.

  Reviewed by:	emaste, dim
  Approved by:	emaste
  Differential Revision:	https://reviews.freebsd.org/D10838

MFC r318884 (by emaste):

  lldb: map TRAP_CAP to a trace trap

  In the absense of a more specific handler for TRAP_CAP (generated by
  ENOTCAPABLE or ECAPMODE while in capability mode) treat it as a trace
  trap.

  Example usage (testing the bug in PR219173):

  % proccontrol -m trapcap lldb usr.bin/hexdump/obj/hexdump -- -Cv -s 1 /bin/ls
  ...
  (lldb) run
  Process 12980 launching
  Process 12980 launched: '.../usr.bin/hexdump/obj/hexdump' (x86_64)
  Process 12980 stopped
  * thread #1, stop reason = trace
      frame #0: 0x0000004b80c65f1a libc.so.7`__sys_lseek + 10
  ...

  In the future we should have LLDB control the trapcap procctl itself
  (as it does with ASLR), as well as report a specific stop reason.
  This change eliminates an assertion failure from LLDB for now.

MFC r319796:

  Remove a few unneeded files from libllvm, libclang and liblldb.

MFC r319885 (by emaste):

  lld: ELF: Fix ICF crash on absolute symbol relocations.

  If two sections contained relocations to absolute symbols with the same
  value we would crash when trying to access their sections. Add a check that
  both symbols point to sections before accessing their sections, and treat
  absolute symbols as equal if their values are equal.

  Obtained from:	LLD commit r292578

MFC r319918:

  Revert r319796 for now, it can cause undefined references when linking
  in some circumstances.

  Reported by:	Shawn Webb <shawn.webb@hardenedbsd.org>

MFC r319957 (by emaste):

  lld: Add armelf emulation mode

  Obtained from:	LLD r305375

MFC r321369:

  Upgrade our copies of clang, llvm, lld, lldb, compiler-rt and libc++ to
  5.0.0 (trunk r308421).  Upstream has branched for the 5.0.0 release,
  which should be in about a month.  Please report bugs and regressions,
  so we can get them into the release.

  Please note that from 3.5.0 onwards, clang, llvm and lldb require C++11
  support to build; see UPDATING for more information.

MFC r321420:

  Add a few more object files to liblldb, which should solve errors when
  linking the lldb executable in some cases.  In particular, when the
  -ffunction-sections -fdata-sections options are turned off, or
  ineffective.

  Reported by:	Shawn Webb, Mark Millard

MFC r321433:

  Cleanup stale Options.inc files from the previous libllvm build for
  clang 4.0.0.  Otherwise, these can get included before the two newly
  generated ones (which are different) for clang 5.0.0.

  Reported by:	Mark Millard

MFC r321439 (by bdrewery):

  Move llvm Options.inc hack from r321433 for NO_CLEAN to lib/clang/libllvm.

  The files are only ever generated to .OBJDIR, not to WORLDTMP (as a
  sysroot) and are only ever included from a compilation.  So using
  a beforebuild target here removes the file before the compilation
  tries to include it.

MFC r321664:

  Pull in r308891 from upstream llvm trunk (by Benjamin Kramer):

    [CodeGenPrepare] Cut off FindAllMemoryUses if there are too many uses.

    This avoids excessive compile time. The case I'm looking at is
    Function.cpp from an old version of LLVM that still had the giant
    memcmp string matcher in it. Before r308322 this compiled in about 2
    minutes, after it, clang takes infinite* time to compile it. With
    this patch we're at 5 min, which is still bad but this is a
    pathological case.

    The cut off at 20 uses was chosen by looking at other cut-offs in LLVM
    for user scanning. It's probably too high, but does the job and is
    very unlikely to regress anything.

    Fixes PR33900.

    * I'm impatient and aborted after 15 minutes, on the bug report it was
      killed after 2h.

  Pull in r308986 from upstream llvm trunk (by Simon Pilgrim):

    [X86][CGP] Reduce memcmp() expansion to 2 load pairs (PR33914)

    D35067/rL308322 attempted to support up to 4 load pairs for memcmp
    inlining which resulted in regressions for some optimized libc memcmp
    implementations (PR33914).

    Until we can match these more optimal cases, this patch reduces the
    memcmp expansion to a maximum of 2 load pairs (which matches what we
    do for -Os).

    This patch should be considered for the 5.0.0 release branch as well

    Differential Revision: https://reviews.llvm.org/D35830

  These fix a hang (or extremely long compile time) when building older
  LLVM ports.

  Reported by:    antoine
  PR:             219139

MFC r321719:

  Pull in r309503 from upstream clang trunk (by Richard Smith):

    PR33902: Invalidate line number cache when adding more text to
    existing buffer.

    This led to crashes as the line number cache would report a bogus
    line number for a line of code, and we'd try to find a nonexistent
    column within the line when printing diagnostics.

  This fixes an assertion when building the graphics/champlain port.

  Reported by:	antoine, kwm
  PR:		219139

MFC r321723:

  Upgrade our copies of clang, llvm, lld and lldb to r309439 from the
  upstream release_50 branch.  This is just after upstream's 5.0.0-rc1.

MFC r322320:

  Upgrade our copies of clang, llvm and libc++ to r310316 from the
  upstream release_50 branch.

MFC r322326 (by emaste):

  lldb: Make i386-*-freebsd expression work on JIT path

  * Enable i386 ABI creation for freebsd
  * Added an extra argument in ABISysV_i386::PrepareTrivialCall for mmap
    syscall
  * Unlike linux, the last argument of mmap is actually 64-bit(off_t).
    This requires us to push an additional word for the higher order bits.
  * Prior to this change, ktrace dump will show mmap failures due to
    invalid argument coming from the 6th mmap argument.

  Submitted by:	Karnajit Wangkhem
  Differential Revision:	https://reviews.llvm.org/D34776

MFC r322360 (by emaste):

  lldb: Report inferior signals as signals, not exceptions, on FreeBSD

  This is the FreeBSD equivalent of LLVM r238549.

  This serves 2 purposes:

  * LLDB should handle inferior process signals SIGSEGV/SIGILL/SIGBUS/
    SIGFPE the way it is suppose to be handled. Prior to this fix these
    signals will neither create a coredump, nor exit from the debugger
    or work for signal handling scenario.
  * eInvalidCrashReason need not report "unknown crash reason" if we have
    a valid si_signo

  llvm.org/pr23699

  Patch by Karnajit Wangkhem

  Differential Revision:  https://reviews.llvm.org/D35223

  Submitted by:	Karnajit Wangkhem
  Obtained from:	LLVM r310591

MFC r322474 (by emaste):

  lld: Add `-z muldefs` option.

  Obtained from:	LLVM r310757

MFC r322740:

  Upgrade our copies of clang, llvm, lld and libc++ to r311219 from the
  upstream release_50 branch.

MFC r322855:

  Upgrade our copies of clang, llvm, lldb and compiler-rt to r311606 from
  the upstream release_50 branch.

  As of this version, lib/msun's trig test should also work correctly
  again (see bug 220989 for more information).

  PR:		220989

MFC r323112:

  Upgrade our copies of clang, llvm, lldb and compiler-rt to r312293 from
  the upstream release_50 branch.  This corresponds to 5.0.0 rc4.

  As of this version, the cad/stepcode port should now compile in a more
  reasonable time on i386 (see bug 221836 for more information).

  PR:		221836

MFC r323245:

  Upgrade our copies of clang, llvm, lld, lldb, compiler-rt and libc++ to
  5.0.0 release (upstream r312559).

  Release notes for llvm, clang and lld will be available here soon:
  <http://releases.llvm.org/5.0.0/docs/ReleaseNotes.html>
  <http://releases.llvm.org/5.0.0/tools/clang/docs/ReleaseNotes.html>
  <http://releases.llvm.org/5.0.0/tools/lld/docs/ReleaseNotes.html>

  Relnotes:	yes

(cherry picked from commit 12cd91cf4c6b96a24427c0de5374916f2808d263)

1 files changed, 265 insertions, 97 deletions

diff --git a/contrib/llvm/tools/clang/lib/Format/BreakableToken.h b/contrib/llvm/tools/clang/lib/Format/BreakableToken.h
index eb1f9fd..e642a53 100644
--- a/contrib/llvm/tools/clang/lib/Format/BreakableToken.h
+++ b/contrib/llvm/tools/clang/lib/Format/BreakableToken.h
@@ -8,9 +8,10 @@
 //===----------------------------------------------------------------------===//
 ///
 /// \file
-/// \brief Declares BreakableToken, BreakableStringLiteral, and
-/// BreakableBlockComment classes, that contain token type-specific logic to
-/// break long lines in tokens.
+/// \brief Declares BreakableToken, BreakableStringLiteral, BreakableComment,
+/// BreakableBlockComment and BreakableLineCommentSection classes, that contain
+/// token type-specific logic to break long lines in tokens and reflow content
+/// between tokens.
 ///
 //===----------------------------------------------------------------------===//
 
@@ -20,15 +21,49 @@
 #include "Encoding.h"
 #include "TokenAnnotator.h"
 #include "WhitespaceManager.h"
+#include "llvm/Support/Regex.h"
 #include <utility>
 
 namespace clang {
 namespace format {
 
+/// \brief Checks if \p Token switches formatting, like /* clang-format off */.
+/// \p Token must be a comment.
+bool switchesFormatting(const FormatToken &Token);
+
 struct FormatStyle;
 
 /// \brief Base class for strategies on how to break tokens.
 ///
+/// This is organised around the concept of a \c Split, which is a whitespace
+/// range that signifies a position of the content of a token where a
+/// reformatting might be done. Operating with splits is divided into 3
+/// operations:
+/// - getSplit, for finding a split starting at a position,
+/// - getLineLengthAfterSplit, for calculating the size in columns of the rest
+///   of the content after a split has been used for breaking, and
+/// - insertBreak, for executing the split using a whitespace manager.
+///
+/// There is a pair of operations that are used to compress a long whitespace
+/// range with a single space if that will bring the line lenght under the
+/// column limit:
+/// - getLineLengthAfterCompression, for calculating the size in columns of the
+///   line after a whitespace range has been compressed, and
+/// - compressWhitespace, for executing the whitespace compression using a
+///   whitespace manager; note that the compressed whitespace may be in the
+///   middle of the original line and of the reformatted line.
+///
+/// For tokens where the whitespace before each line needs to be also
+/// reformatted, for example for tokens supporting reflow, there are analogous
+/// operations that might be executed before the main line breaking occurs:
+/// - getSplitBefore, for finding a split such that the content preceding it
+///   needs to be specially reflown,
+/// - getLineLengthAfterSplitBefore, for calculating the line length in columns
+///   of the remainder of the content after the beginning of the content has
+///   been reformatted, and
+/// - replaceWhitespaceBefore, for executing the reflow using a whitespace
+///   manager.
+///
 /// FIXME: The interface seems set in stone, so we might want to just pull the
 /// strategy into the class, instead of controlling it from the outside.
 class BreakableToken {
@@ -42,44 +77,85 @@ public:
   virtual unsigned getLineCount() const = 0;
 
   /// \brief Returns the number of columns required to format the piece of line
-  /// at \p LineIndex, from byte offset \p Offset with length \p Length.
+  /// at \p LineIndex, from byte offset \p TailOffset with length \p Length.
   ///
-  /// Note that previous breaks are not taken into account. \p Offset is always
-  /// specified from the start of the (original) line.
+  /// Note that previous breaks are not taken into account. \p TailOffset is
+  /// always specified from the start of the (original) line.
   /// \p Length can be set to StringRef::npos, which means "to the end of line".
   virtual unsigned
-  getLineLengthAfterSplit(unsigned LineIndex, unsigned Offset,
+  getLineLengthAfterSplit(unsigned LineIndex, unsigned TailOffset,
                           StringRef::size_type Length) const = 0;
 
   /// \brief Returns a range (offset, length) at which to break the line at
   /// \p LineIndex, if previously broken at \p TailOffset. If possible, do not
   /// violate \p ColumnLimit.
   virtual Split getSplit(unsigned LineIndex, unsigned TailOffset,
-                         unsigned ColumnLimit) const = 0;
+                         unsigned ColumnLimit,
+                         llvm::Regex &CommentPragmasRegex) const = 0;
 
   /// \brief Emits the previously retrieved \p Split via \p Whitespaces.
   virtual void insertBreak(unsigned LineIndex, unsigned TailOffset, Split Split,
                            WhitespaceManager &Whitespaces) = 0;
 
+  /// \brief Returns the number of columns required to format the piece of line
+  /// at \p LineIndex, from byte offset \p TailOffset after the whitespace range
+  /// \p Split has been compressed into a single space.
+  unsigned getLineLengthAfterCompression(unsigned RemainingTokenColumns,
+                                         Split Split) const;
+
   /// \brief Replaces the whitespace range described by \p Split with a single
   /// space.
-  virtual void replaceWhitespace(unsigned LineIndex, unsigned TailOffset,
-                                 Split Split,
-                                 WhitespaceManager &Whitespaces) = 0;
+  virtual void compressWhitespace(unsigned LineIndex, unsigned TailOffset,
+                                  Split Split,
+                                  WhitespaceManager &Whitespaces) = 0;
+
+  /// \brief Returns a whitespace range (offset, length) of the content at
+  /// \p LineIndex such that the content preceding this range needs to be
+  /// reformatted before any breaks are made to this line.
+  ///
+  /// \p PreviousEndColumn is the end column of the previous line after
+  /// formatting.
+  ///
+  /// A result having offset == StringRef::npos means that no piece of the line
+  /// needs to be reformatted before any breaks are made.
+  virtual Split getSplitBefore(unsigned LineIndex, unsigned PreviousEndColumn,
+                               unsigned ColumnLimit,
+                               llvm::Regex &CommentPragmasRegex) const {
+    return Split(StringRef::npos, 0);
+  }
+
+  /// \brief Returns the number of columns required to format the piece of line
+  /// at \p LineIndex after the content preceding the whitespace range specified
+  /// \p SplitBefore has been reformatted, but before any breaks are made to
+  /// this line.
+  virtual unsigned getLineLengthAfterSplitBefore(unsigned LineIndex,
+                                                 unsigned TailOffset,
+                                                 unsigned PreviousEndColumn,
+                                                 unsigned ColumnLimit,
+                                                 Split SplitBefore) const {
+    return getLineLengthAfterSplit(LineIndex, TailOffset, StringRef::npos);
+  }
 
   /// \brief Replaces the whitespace between \p LineIndex-1 and \p LineIndex.
+  /// Performs a reformatting of the content at \p LineIndex preceding the
+  /// whitespace range \p SplitBefore.
   virtual void replaceWhitespaceBefore(unsigned LineIndex,
+                                       unsigned PreviousEndColumn,
+                                       unsigned ColumnLimit, Split SplitBefore,
                                        WhitespaceManager &Whitespaces) {}
 
+  /// \brief Updates the next token of \p State to the next token after this
+  /// one. This can be used when this token manages a set of underlying tokens
+  /// as a unit and is responsible for the formatting of the them.
+  virtual void updateNextToken(LineState &State) const {}
+
 protected:
-  BreakableToken(const FormatToken &Tok, unsigned IndentLevel,
-                 bool InPPDirective, encoding::Encoding Encoding,
-                 const FormatStyle &Style)
-      : Tok(Tok), IndentLevel(IndentLevel), InPPDirective(InPPDirective),
-        Encoding(Encoding), Style(Style) {}
+  BreakableToken(const FormatToken &Tok, bool InPPDirective,
+                 encoding::Encoding Encoding, const FormatStyle &Style)
+      : Tok(Tok), InPPDirective(InPPDirective), Encoding(Encoding),
+        Style(Style) {}
 
   const FormatToken &Tok;
-  const unsigned IndentLevel;
   const bool InPPDirective;
   const encoding::Encoding Encoding;
   const FormatStyle &Style;
@@ -95,10 +171,9 @@ public:
                                    StringRef::size_type Length) const override;
 
 protected:
-  BreakableSingleLineToken(const FormatToken &Tok, unsigned IndentLevel,
-                           unsigned StartColumn, StringRef Prefix,
-                           StringRef Postfix, bool InPPDirective,
-                           encoding::Encoding Encoding,
+  BreakableSingleLineToken(const FormatToken &Tok, unsigned StartColumn,
+                           StringRef Prefix, StringRef Postfix,
+                           bool InPPDirective, encoding::Encoding Encoding,
                            const FormatStyle &Style);
 
   // The column in which the token starts.
@@ -117,107 +192,139 @@ public:
   ///
   /// \p StartColumn specifies the column in which the token will start
   /// after formatting.
-  BreakableStringLiteral(const FormatToken &Tok, unsigned IndentLevel,
-                         unsigned StartColumn, StringRef Prefix,
-                         StringRef Postfix, bool InPPDirective,
-                         encoding::Encoding Encoding, const FormatStyle &Style);
+  BreakableStringLiteral(const FormatToken &Tok, unsigned StartColumn,
+                         StringRef Prefix, StringRef Postfix,
+                         bool InPPDirective, encoding::Encoding Encoding,
+                         const FormatStyle &Style);
 
-  Split getSplit(unsigned LineIndex, unsigned TailOffset,
-                 unsigned ColumnLimit) const override;
+  Split getSplit(unsigned LineIndex, unsigned TailOffset, unsigned ColumnLimit,
+                 llvm::Regex &CommentPragmasRegex) const override;
   void insertBreak(unsigned LineIndex, unsigned TailOffset, Split Split,
                    WhitespaceManager &Whitespaces) override;
-  void replaceWhitespace(unsigned LineIndex, unsigned TailOffset, Split Split,
-                         WhitespaceManager &Whitespaces) override {}
+  void compressWhitespace(unsigned LineIndex, unsigned TailOffset, Split Split,
+                          WhitespaceManager &Whitespaces) override {}
 };
 
-class BreakableLineComment : public BreakableSingleLineToken {
-public:
-  /// \brief Creates a breakable token for a line comment.
+class BreakableComment : public BreakableToken {
+protected:
+  /// \brief Creates a breakable token for a comment.
   ///
-  /// \p StartColumn specifies the column in which the comment will start
-  /// after formatting.
-  BreakableLineComment(const FormatToken &Token, unsigned IndentLevel,
-                       unsigned StartColumn, bool InPPDirective,
-                       encoding::Encoding Encoding, const FormatStyle &Style);
+  /// \p StartColumn specifies the column in which the comment will start after
+  /// formatting.
+  BreakableComment(const FormatToken &Token, unsigned StartColumn,
+                   bool InPPDirective, encoding::Encoding Encoding,
+                   const FormatStyle &Style);
 
-  Split getSplit(unsigned LineIndex, unsigned TailOffset,
-                 unsigned ColumnLimit) const override;
-  void insertBreak(unsigned LineIndex, unsigned TailOffset, Split Split,
-                   WhitespaceManager &Whitespaces) override;
-  void replaceWhitespace(unsigned LineIndex, unsigned TailOffset, Split Split,
-                         WhitespaceManager &Whitespaces) override;
-  void replaceWhitespaceBefore(unsigned LineIndex,
-                               WhitespaceManager &Whitespaces) override;
+public:
+  unsigned getLineCount() const override;
+  Split getSplit(unsigned LineIndex, unsigned TailOffset, unsigned ColumnLimit,
+                 llvm::Regex &CommentPragmasRegex) const override;
+  void compressWhitespace(unsigned LineIndex, unsigned TailOffset, Split Split,
+                          WhitespaceManager &Whitespaces) override;
 
-private:
-  // The prefix without an additional space if one was added.
-  StringRef OriginalPrefix;
+protected:
+  virtual unsigned getContentStartColumn(unsigned LineIndex,
+                                         unsigned TailOffset) const = 0;
+
+  // Returns a split that divides Text into a left and right parts, such that
+  // the left part is suitable for reflowing after PreviousEndColumn.
+  Split getReflowSplit(StringRef Text, StringRef ReflowPrefix,
+                       unsigned PreviousEndColumn, unsigned ColumnLimit) const;
+
+  // Returns the token containing the line at LineIndex.
+  const FormatToken &tokenAt(unsigned LineIndex) const;
+
+  // Checks if the content of line LineIndex may be reflown with the previous
+  // line.
+  virtual bool mayReflow(unsigned LineIndex,
+                         llvm::Regex &CommentPragmasRegex) const = 0;
+
+  // Contains the original text of the lines of the block comment.
+  //
+  // In case of a block comments, excludes the leading /* in the first line and
+  // trailing */ in the last line. In case of line comments, excludes the
+  // leading // and spaces.
+  SmallVector<StringRef, 16> Lines;
+
+  // Contains the text of the lines excluding all leading and trailing
+  // whitespace between the lines. Note that the decoration (if present) is also
+  // not considered part of the text.
+  SmallVector<StringRef, 16> Content;
+
+  // Tokens[i] contains a reference to the token containing Lines[i] if the
+  // whitespace range before that token is managed by this block.
+  // Otherwise, Tokens[i] is a null pointer.
+  SmallVector<FormatToken *, 16> Tokens;
+
+  // ContentColumn[i] is the target column at which Content[i] should be.
+  // Note that this excludes a leading "* " or "*" in case of block comments
+  // where all lines have a "*" prefix, or the leading "// " or "//" in case of
+  // line comments.
+  //
+  // In block comments, the first line's target column is always positive. The
+  // remaining lines' target columns are relative to the first line to allow
+  // correct indentation of comments in \c WhitespaceManager. Thus they can be
+  // negative as well (in case the first line needs to be unindented more than
+  // there's actual whitespace in another line).
+  SmallVector<int, 16> ContentColumn;
+
+  // The intended start column of the first line of text from this section.
+  unsigned StartColumn;
+
+  // The prefix to use in front a line that has been reflown up.
+  // For example, when reflowing the second line after the first here:
+  // // comment 1
+  // // comment 2
+  // we expect:
+  // // comment 1 comment 2
+  // and not:
+  // // comment 1comment 2
+  StringRef ReflowPrefix = " ";
 };
 
-class BreakableBlockComment : public BreakableToken {
+class BreakableBlockComment : public BreakableComment {
 public:
-  /// \brief Creates a breakable token for a block comment.
-  ///
-  /// \p StartColumn specifies the column in which the comment will start
-  /// after formatting, while \p OriginalStartColumn specifies in which
-  /// column the comment started before formatting.
-  /// If the comment starts a line after formatting, set \p FirstInLine to true.
-  BreakableBlockComment(const FormatToken &Token, unsigned IndentLevel,
-                        unsigned StartColumn, unsigned OriginaStartColumn,
-                        bool FirstInLine, bool InPPDirective,
-                        encoding::Encoding Encoding, const FormatStyle &Style);
+  BreakableBlockComment(const FormatToken &Token, unsigned StartColumn,
+                        unsigned OriginalStartColumn, bool FirstInLine,
+                        bool InPPDirective, encoding::Encoding Encoding,
+                        const FormatStyle &Style);
 
-  unsigned getLineCount() const override;
   unsigned getLineLengthAfterSplit(unsigned LineIndex, unsigned TailOffset,
                                    StringRef::size_type Length) const override;
-  Split getSplit(unsigned LineIndex, unsigned TailOffset,
-                 unsigned ColumnLimit) const override;
   void insertBreak(unsigned LineIndex, unsigned TailOffset, Split Split,
                    WhitespaceManager &Whitespaces) override;
-  void replaceWhitespace(unsigned LineIndex, unsigned TailOffset, Split Split,
-                         WhitespaceManager &Whitespaces) override;
-  void replaceWhitespaceBefore(unsigned LineIndex,
+  Split getSplitBefore(unsigned LineIndex, unsigned PreviousEndColumn,
+                       unsigned ColumnLimit,
+                       llvm::Regex &CommentPragmasRegex) const override;
+  unsigned getLineLengthAfterSplitBefore(unsigned LineIndex,
+                                         unsigned TailOffset,
+                                         unsigned PreviousEndColumn,
+                                         unsigned ColumnLimit,
+                                         Split SplitBefore) const override;
+  void replaceWhitespaceBefore(unsigned LineIndex, unsigned PreviousEndColumn,
+                               unsigned ColumnLimit, Split SplitBefore,
                                WhitespaceManager &Whitespaces) override;
+  bool mayReflow(unsigned LineIndex,
+                 llvm::Regex &CommentPragmasRegex) const override;
 
 private:
-  // Rearranges the whitespace between Lines[LineIndex-1] and Lines[LineIndex],
-  // so that all whitespace between the lines is accounted to Lines[LineIndex]
-  // as leading whitespace:
-  // - Lines[LineIndex] points to the text after that whitespace
-  // - Lines[LineIndex-1] shrinks by its trailing whitespace
-  // - LeadingWhitespace[LineIndex] is updated with the complete whitespace
-  //   between the end of the text of Lines[LineIndex-1] and Lines[LineIndex]
+  // Rearranges the whitespace between Lines[LineIndex-1] and Lines[LineIndex].
   //
-  // Sets StartOfLineColumn to the intended column in which the text at
+  // Updates Content[LineIndex-1] and Content[LineIndex] by stripping off
+  // leading and trailing whitespace.
+  //
+  // Sets ContentColumn to the intended column in which the text at
   // Lines[LineIndex] starts (note that the decoration, if present, is not
   // considered part of the text).
   void adjustWhitespace(unsigned LineIndex, int IndentDelta);
 
-  // Returns the column at which the text in line LineIndex starts, when broken
-  // at TailOffset. Note that the decoration (if present) is not considered part
-  // of the text.
-  unsigned getContentStartColumn(unsigned LineIndex, unsigned TailOffset) const;
-
-  // Contains the text of the lines of the block comment, excluding the leading
-  // /* in the first line and trailing */ in the last line, and excluding all
-  // trailing whitespace between the lines. Note that the decoration (if
-  // present) is also not considered part of the text.
-  SmallVector<StringRef, 16> Lines;
+  // Computes the end column if the full Content from LineIndex gets reflown
+  // after PreviousEndColumn.
+  unsigned getReflownColumn(StringRef Content, unsigned LineIndex,
+                            unsigned PreviousEndColumn) const;
 
-  // LeadingWhitespace[i] is the number of characters regarded as whitespace in
-  // front of Lines[i]. Note that this can include "* " sequences, which we
-  // regard as whitespace when all lines have a "*" prefix.
-  SmallVector<unsigned, 16> LeadingWhitespace;
-
-  // StartOfLineColumn[i] is the target column at which Line[i] should be.
-  // Note that this excludes a leading "* " or "*" in case all lines have
-  // a "*" prefix.
-  // The first line's target column is always positive. The remaining lines'
-  // target columns are relative to the first line to allow correct indentation
-  // of comments in \c WhitespaceManager. Thus they can be negative as well (in
-  // case the first line needs to be unindented more than there's actual
-  // whitespace in another line).
-  SmallVector<int, 16> StartOfLineColumn;
+  unsigned getContentStartColumn(unsigned LineIndex,
+                                 unsigned TailOffset) const override;
 
   // The column at which the text of a broken line should start.
   // Note that an optional decoration would go before that column.
@@ -237,8 +344,69 @@ private:
 
   // Either "* " if all lines begin with a "*", or empty.
   StringRef Decoration;
+
+  // If this block comment has decorations, this is the column of the start of
+  // the decorations.
+  unsigned DecorationColumn;
 };
 
+class BreakableLineCommentSection : public BreakableComment {
+public:
+  BreakableLineCommentSection(const FormatToken &Token, unsigned StartColumn,
+                              unsigned OriginalStartColumn, bool FirstInLine,
+                              bool InPPDirective, encoding::Encoding Encoding,
+                              const FormatStyle &Style);
+
+  unsigned getLineLengthAfterSplit(unsigned LineIndex, unsigned TailOffset,
+                                   StringRef::size_type Length) const override;
+  void insertBreak(unsigned LineIndex, unsigned TailOffset, Split Split,
+                   WhitespaceManager &Whitespaces) override;
+  Split getSplitBefore(unsigned LineIndex, unsigned PreviousEndColumn,
+                       unsigned ColumnLimit,
+                       llvm::Regex &CommentPragmasRegex) const override;
+  unsigned getLineLengthAfterSplitBefore(unsigned LineIndex,
+                                         unsigned TailOffset,
+                                         unsigned PreviousEndColumn,
+                                         unsigned ColumnLimit,
+                                         Split SplitBefore) const override;
+  void replaceWhitespaceBefore(unsigned LineIndex, unsigned PreviousEndColumn,
+                               unsigned ColumnLimit, Split SplitBefore,
+                               WhitespaceManager &Whitespaces) override;
+  void updateNextToken(LineState &State) const override;
+  bool mayReflow(unsigned LineIndex,
+                 llvm::Regex &CommentPragmasRegex) const override;
+
+private:
+  unsigned getContentStartColumn(unsigned LineIndex,
+                                 unsigned TailOffset) const override;
+
+  // OriginalPrefix[i] contains the original prefix of line i, including
+  // trailing whitespace before the start of the content. The indentation
+  // preceding the prefix is not included.
+  // For example, if the line is:
+  // // content
+  // then the original prefix is "// ".
+  SmallVector<StringRef, 16> OriginalPrefix;
+
+  // Prefix[i] contains the intended leading "//" with trailing spaces to
+  // account for the indentation of content within the comment at line i after
+  // formatting. It can be different than the original prefix when the original
+  // line starts like this:
+  // //content
+  // Then the original prefix is "//", but the prefix is "// ".
+  SmallVector<StringRef, 16> Prefix;
+
+  SmallVector<unsigned, 16> OriginalContentColumn;
+
+  /// \brief The token to which the last line of this breakable token belongs
+  /// to; nullptr if that token is the initial token.
+  ///
+  /// The distinction is because if the token of the last line of this breakable
+  /// token is distinct from the initial token, this breakable token owns the
+  /// whitespace before the token of the last line, and the whitespace manager
+  /// must be able to modify it.
+  FormatToken *LastLineTok = nullptr;
+};
 } // namespace format
 } // namespace clang