clang-format: Fix infinite loop in macro special case.

If escaped newlines are aligned right
(FormatStyle.AlignEscapedNewlinesLeft == false), and a line contained
too many characters to fit into the column limit, this would result in
a (virtually) endless loop creating a negative number of spaces.

Instead, allow the escaped newlines to be pushed past the column limit
in this case.

This fixes llvm.org/PR16515.

llvm-svn: 189459

1 files changed, 4 insertions, 6 deletions

diff --git a/clang/lib/Format/WhitespaceManager.cpp b/clang/lib/Format/WhitespaceManager.cpp
index 94aca02..41519b6 100644
--- a/clang/lib/Format/WhitespaceManager.cpp
+++ b/clang/lib/Format/WhitespaceManager.cpp
@@ -185,19 +185,17 @@ void WhitespaceManager::alignTrailingComments(unsigned Start, unsigned End,
 }
 
 void WhitespaceManager::alignEscapedNewlines() {
-  unsigned MaxEndOfLine = 0;
+  unsigned MaxEndOfLine =
+      Style.AlignEscapedNewlinesLeft ? 0 : Style.ColumnLimit;
   unsigned StartOfMacro = 0;
   for (unsigned i = 1, e = Changes.size(); i < e; ++i) {
     Change &C = Changes[i];
     if (C.NewlinesBefore > 0) {
       if (C.ContinuesPPDirective) {
-        if (Style.AlignEscapedNewlinesLeft)
-          MaxEndOfLine = std::max(C.PreviousEndOfTokenColumn + 2, MaxEndOfLine);
-        else
-          MaxEndOfLine = Style.ColumnLimit;
+        MaxEndOfLine = std::max(C.PreviousEndOfTokenColumn + 2, MaxEndOfLine);
       } else {
         alignEscapedNewlines(StartOfMacro + 1, i, MaxEndOfLine);
-        MaxEndOfLine = 0;
+        MaxEndOfLine = Style.AlignEscapedNewlinesLeft ? 0 : Style.ColumnLimit;
         StartOfMacro = i;
       }
     }