From be9ed776e57fe606b5826a0d37a5a2dbfb927e63 Mon Sep 17 00:00:00 2001
From: Manuel Klimek <klimek@google.com>
Date: Wed, 29 May 2013 22:06:18 +0000
Subject: [PATCH] Fixes error when splitting block comments.

When trying to fall back to search from the end onwards, we
would still find leading whitespace if the leading whitespace
went on after the end of the line.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@182886 91177308-0d34-0410-b5e6-96231b3b80d8
---
 lib/Format/BreakableToken.cpp   | 12 ++++++++++--
 unittests/Format/FormatTest.cpp | 27 +++++++++++++++++++++++++++
 2 files changed, 37 insertions(+), 2 deletions(-)

diff --git a/lib/Format/BreakableToken.cpp b/lib/Format/BreakableToken.cpp
index c102f8b1b2..5c3ad9cee2 100644
--- a/lib/Format/BreakableToken.cpp
+++ b/lib/Format/BreakableToken.cpp
@@ -87,8 +87,16 @@ BreakableToken::Split getCommentSplit(StringRef Text,
   StringRef::size_type SpaceOffset = Text.rfind(' ', MaxSplit);
   if (SpaceOffset == StringRef::npos ||
       // Don't break at leading whitespace.
-      Text.find_last_not_of(' ', SpaceOffset) == StringRef::npos)
-    SpaceOffset = Text.find(' ', MaxSplit);
+      Text.find_last_not_of(' ', 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(" ");
+    if (FirstNonWhitespace == StringRef::npos)
+      // If the comment is only whitespace, we cannot split.
+      return BreakableToken::Split(StringRef::npos, 0);
+    SpaceOffset =
+        Text.find(' ', std::max<unsigned>(MaxSplit, FirstNonWhitespace));
+  }
   if (SpaceOffset != StringRef::npos && SpaceOffset != 0) {
     StringRef BeforeCut = Text.substr(0, SpaceOffset).rtrim();
     StringRef AfterCut = Text.substr(SpaceOffset).ltrim();
diff --git a/unittests/Format/FormatTest.cpp b/unittests/Format/FormatTest.cpp
index 18a1a00858..1f4f4806c3 100644
--- a/unittests/Format/FormatTest.cpp
+++ b/unittests/Format/FormatTest.cpp
@@ -3694,6 +3694,33 @@ TEST_F(FormatTest, BlockCommentsInMacros) {
                    getLLVMStyleWithColumns(20)));
 }
 
+TEST_F(FormatTest, BlockCommentsAtEndOfLine) {
+  EXPECT_EQ("a = {\n"
+            "  1111 /*    */\n"
+            "};",
+            format("a = {1111\n"
+                   "/*    */\n"
+                   "};",
+                   getLLVMStyleWithColumns(15)));
+  EXPECT_EQ("a = {\n"
+            "  1111 /*      */\n"
+            "};",
+            format("a = {1111\n"
+                   "/*      */\n"
+                   "};",
+                   getLLVMStyleWithColumns(15)));
+
+  // FIXME: The formatting is still wrong here.
+  EXPECT_EQ("a = {\n"
+            "  1111 /*      a\n"
+            "          */\n"
+            "};",
+            format("a = {1111\n"
+                   "/*      a */\n"
+                   "};",
+                   getLLVMStyleWithColumns(15)));
+}
+
 TEST_F(FormatTest, IndentLineCommentsInStartOfBlockAtEndOfFile) {
   // FIXME: This is not what we want...
   verifyFormat("{\n"
-- 
2.40.0