[clang-format] Add a NamespaceEndCommentsFixer

Summary:
This patch adds a NamespaceEndCommentsFixer TokenAnalyzer for clang-format,
which fixes end namespace comments.
It currently supports inserting and updating existing wrong comments.

Example source:
```
namespace A {
int i;
}

namespace B {
int j;
} // namespace A
```

after formatting:
```
namespace A {
int i;
} // namespace A

namespace B {
int j;
} // namespace B
```

Reviewers: klimek, djasper

Reviewed By: djasper

Subscribers: klimek, mgorny

Differential Revision: https://reviews.llvm.org/D30269

llvm-svn: 296341

1 files changed, 3 insertions, 0 deletions

diff --git a/clang/lib/Format/UnwrappedLineParser.cpp b/clang/lib/Format/UnwrappedLineParser.cpp
index ab343d8bbed..9a536ad6019 100644
--- a/clang/lib/Format/UnwrappedLineParser.cpp
+++ b/clang/lib/Format/UnwrappedLineParser.cpp
@@ -428,6 +428,8 @@ void UnwrappedLineParser::parseBlock(bool MustBeDeclaration, bool AddLevel,
     parseParens();
 
   addUnwrappedLine();
+  size_t OpeningLineIndex =
+      Lines.empty() ? (UnwrappedLine::kInvalidIndex) : (Lines.size() - 1);
 
   ScopedDeclarationState DeclarationState(*Line, DeclarationScopeStack,
                                           MustBeDeclaration);
@@ -453,6 +455,7 @@ void UnwrappedLineParser::parseBlock(bool MustBeDeclaration, bool AddLevel,
   if (MunchSemi && FormatTok->Tok.is(tok::semi))
     nextToken();
   Line->Level = InitialLevel;
+  Line->MatchingOpeningBlockLineIndex = OpeningLineIndex;
 }
 
 static bool isGoogScope(const UnwrappedLine &Line) {