From 0ce1c9ade71a2ed56dafddcd5d95e4e75fd91255 Mon Sep 17 00:00:00 2001
From: Daniel Jasper <djasper@google.com>
Date: Fri, 8 Nov 2013 23:31:14 +0000
Subject: [PATCH] clang-format: Improve clang-format's detection about comment
 binding.

Before, existing code in the form of:

  int a; // this is a.
  // This is
  // b.
  int b;

Got turned into:

  int a; // this is a.
         // This is
  // b.
  int b;

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@194294 91177308-0d34-0410-b5e6-96231b3b80d8
---
 lib/Format/WhitespaceManager.cpp | 28 +++++++++++++++-------------
 unittests/Format/FormatTest.cpp  | 20 ++++++++++++++++++++
 2 files changed, 35 insertions(+), 13 deletions(-)

diff --git a/lib/Format/WhitespaceManager.cpp b/lib/Format/WhitespaceManager.cpp
index c24ccdfee4..26a8d41e87 100644
--- a/lib/Format/WhitespaceManager.cpp
+++ b/lib/Format/WhitespaceManager.cpp
@@ -141,19 +141,21 @@ void WhitespaceManager::alignTrailingComments() {
       bool FollowsRBraceInColumn0 = i > 0 && Changes[i].NewlinesBefore == 0 &&
                                     Changes[i - 1].Kind == tok::r_brace &&
                                     Changes[i - 1].StartOfTokenColumn == 0;
-      bool WasAlignedWithStartOfNextLine =
-          // A comment on its own line.
-          Changes[i].NewlinesBefore == 1 &&
-          // Not the last line.
-          i + 1 != e &&
-          // The start of the next token was previously aligned with
-          // the start of this comment.
-          (SourceMgr.getSpellingColumnNumber(
-               Changes[i].OriginalWhitespaceRange.getEnd()) ==
-           SourceMgr.getSpellingColumnNumber(
-               Changes[i + 1].OriginalWhitespaceRange.getEnd())) &&
-          // Which is not a comment itself.
-          Changes[i + 1].Kind != tok::comment;
+      bool WasAlignedWithStartOfNextLine = false;
+      if (Changes[i].NewlinesBefore == 1) { // A comment on its own line.
+        for (unsigned j = i + 1; j != e; ++j) {
+          if (Changes[j].Kind != tok::comment) { // Skip over comments.
+            // The start of the next token was previously aligned with the
+            // start of this comment.
+            WasAlignedWithStartOfNextLine =
+                (SourceMgr.getSpellingColumnNumber(
+                     Changes[i].OriginalWhitespaceRange.getEnd()) ==
+                 SourceMgr.getSpellingColumnNumber(
+                     Changes[j].OriginalWhitespaceRange.getEnd()));
+            break;
+          }
+        }
+      }
       if (!Style.AlignTrailingComments || FollowsRBraceInColumn0) {
         alignTrailingComments(StartOfSequence, i, MinColumn);
         MinColumn = ChangeMinColumn;
diff --git a/unittests/Format/FormatTest.cpp b/unittests/Format/FormatTest.cpp
index 794fb1a64b..e37f0cd4eb 100644
--- a/unittests/Format/FormatTest.cpp
+++ b/unittests/Format/FormatTest.cpp
@@ -787,6 +787,26 @@ TEST_F(FormatTest, UnderstandsSingleLineComments) {
                    "// first\n"
                    " // at start\n"
                    "otherLine();   // comment"));
+  verifyFormat("f(); // comment\n"
+               "// first\n"
+               "// at start\n"
+               "otherLine();");
+  EXPECT_EQ("f(); // comment\n"
+            "// first\n"
+            "// at start\n"
+            "otherLine();",
+            format("f();   // comment\n"
+                   "// first\n"
+                   " // at start\n"
+                   "otherLine();"));
+  EXPECT_EQ("f(); // comment\n"
+            "     // first\n"
+            "// at start\n"
+            "otherLine();",
+            format("f();   // comment\n"
+                   " // first\n"
+                   "// at start\n"
+                   "otherLine();"));
 }
 
 TEST_F(FormatTest, CanFormatCommentsLocally) {
-- 
2.40.0