Make formatting of empty blocks more consistent.

With this patch, the simplified rule is:
If the block is part of a declaration (class, namespace, function,
enum, ..), merge an empty block onto a single line. Otherwise
(specifically for the compound statements of if, for, while, ...),
keep the braces on two separate lines.

The reasons are:
- Mostly the formatting of empty blocks does not matter much.
- Empty compound statements are really rare and are usually just
  inserted while still working on the code. If they are on two lines,
  inserting code is easier. Also, overlooking the "{}" of an
  "if (...) {}" can be really bad.
- Empty declarations are not uncommon, e.g. empty constructors. Putting
  them on one line saves vertical space at no loss of readability.

llvm-svn: 183008

1 files changed, 5 insertions, 4 deletions

diff --git a/clang/lib/Format/Format.cpp b/clang/lib/Format/Format.cpp
index b6e8079b31a..3ae279216f8 100644
--- a/clang/lib/Format/Format.cpp
+++ b/clang/lib/Format/Format.cpp
@@ -1479,20 +1479,21 @@ private:
     AnnotatedLine &Line = *I;
     if (Line.First->isOneOf(tok::kw_if, tok::kw_while, tok::kw_do, tok::r_brace,
                             tok::kw_else, tok::kw_try, tok::kw_catch,
-                            tok::kw_for, tok::kw_namespace,
+                            tok::kw_for,
                             // This gets rid of all ObjC @ keywords and methods.
                             tok::at, tok::minus, tok::plus))
       return;
 
     FormatToken *Tok = (I + 1)->First;
-    if (Tok->getNextNoneComment() == NULL && Tok->is(tok::r_brace) &&
-        !Tok->MustBreakBefore) {
+    if (Tok->is(tok::r_brace) && !Tok->MustBreakBefore &&
+        (Tok->getNextNoneComment() == NULL ||
+         Tok->getNextNoneComment()->is(tok::semi))) {
       // We merge empty blocks even if the line exceeds the column limit.
       Tok->SpacesRequiredBefore = 0;
       Tok->CanBreakBefore = true;
       join(Line, *(I + 1));
       I += 1;
-    } else if (Limit != 0) {
+    } else if (Limit != 0 && Line.First->isNot(tok::kw_namespace)) {
       // Check that we still have three lines and they fit into the limit.
       if (I + 2 == E || (I + 2)->Type == LT_Invalid ||
           !nextTwoLinesFitInto(I, Limit))