[clang-format] Separate line comment sections after a right brace from comment sectio...

Summary:
The following two comment lines form a single comment section:
```
if (1) { // line 1
   // line 2
}
```
This is because the break of a comment section was based on the original column
of the first token of the previous line (in this case, the 'if').
This patch splits these two comment lines into different sections by taking into
account the original column of the right brace preceding the first line comment
where applicable.

Reviewers: djasper

Reviewed By: djasper

Subscribers: cfe-commits, klimek

Differential Revision: https://reviews.llvm.org/D29291

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@293539 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/Format/UnwrappedLineParser.cpp b/lib/Format/UnwrappedLineParser.cpp
index 5e67bde1f241cc24b830c29b8a910cea179b7ac3..c10a13f39e016660e6e48ec508775285678f6083 100644 (file)
--- a/lib/Format/UnwrappedLineParser.cpp
+++ b/lib/Format/UnwrappedLineParser.cpp
@@ -2051,14 +2051,19 @@ static bool continuesLineComment(const FormatToken &FormatTok,
                                  const UnwrappedLine &Line) {
   if (Line.Tokens.empty())
     return false;
-  const FormatToken &FirstLineTok = *Line.Tokens.front().Tok;
+
   // If Line starts with a line comment, then FormatTok continues the comment
-  // section if its original column is greater or equal to the  original start
+  // section if its original column is greater or equal to the original start
   // column of the line.
   //
-  // If Line starts with a a different token, then FormatTok continues the
-  // comment section if its original column greater than the original start
-  // column of the line.
+  // Define the min column token of a line as follows: if a line ends in '{' or
+  // contains a '{' followed by a line comment, then the min column token is
+  // that '{'. Otherwise, the min column token of the line is the first token of
+  // the line.
+  //
+  // If Line starts with a token other than a line comment, then FormatTok
+  // continues the comment section if its original column is greater than the
+  // original start column of the min column token of the line.
   //
   // For example, the second line comment continues the first in these cases:
   // // first line
@@ -2069,6 +2074,11 @@ static bool continuesLineComment(const FormatToken &FormatTok,
   // and:
   // int i; // first line
   //  // second line
+  // and:
+  // do { // first line
+  //      // second line
+  //   int i;
+  // } while (true);
   //
   // The second line comment doesn't continue the first in these cases:
   //   // first line
@@ -2076,9 +2086,31 @@ static bool continuesLineComment(const FormatToken &FormatTok,
   // and:
   // int i; // first line
   // // second line
+  // and:
+  // do { // first line
+  //   // second line
+  //   int i;
+  // } while (true);
+  const FormatToken *MinColumnToken = Line.Tokens.front().Tok;
+
+  // Scan for '{//'. If found, use the column of '{' as a min column for line
+  // comment section continuation.
+  const FormatToken *PreviousToken = nullptr;
+  for (const UnwrappedLineNode Node : Line.Tokens) {
+    if (PreviousToken && PreviousToken->is(tok::l_brace) &&
+        isLineComment(*Node.Tok)) {
+      MinColumnToken = PreviousToken;
+      break;
+    }
+    PreviousToken = Node.Tok;
+  }
+  if (PreviousToken && PreviousToken->is(tok::l_brace)) {
+    MinColumnToken = PreviousToken;
+  }
+
   unsigned MinContinueColumn =
-      FirstLineTok.OriginalColumn +
-      ((isLineComment(FirstLineTok) && !FirstLineTok.Next) ? 0 : 1);
+      MinColumnToken->OriginalColumn +
+      (isLineComment(*MinColumnToken) ? 0 : 1);
   return isLineComment(FormatTok) && FormatTok.NewlinesBefore == 1 &&
          isLineComment(*(Line.Tokens.back().Tok)) &&
          FormatTok.OriginalColumn >= MinContinueColumn;

diff --git a/unittests/Format/FormatTest.cpp b/unittests/Format/FormatTest.cpp
index 2be5062d6f62fd19acecedafd6713695e4e60539..d28200104056ed320f1ec25ae956df759c0aff91 100644 (file)
--- a/unittests/Format/FormatTest.cpp
+++ b/unittests/Format/FormatTest.cpp
@@ -1783,6 +1783,64 @@ TEST_F(FormatTest, CommentsInStaticInitializers) {
                "    0x00, 0x00, 0x00, 0x00};            // comment\n");
 }
 
+TEST_F(FormatTest, LineCommentsAfterRightBrace) {
+  EXPECT_EQ("if (true) { // comment about branch\n"
+            "  // comment about f\n"
+            "  f();\n"
+            "}",
+            format("if (true) { // comment about branch\n"
+                   "  // comment about f\n"
+                   "  f();\n"
+                   "}",
+                   getLLVMStyleWithColumns(80)));
+  EXPECT_EQ("if (1) { // if line 1\n"
+            "         // if line 2\n"
+            "         // if line 3\n"
+            "  // f line 1\n"
+            "  // f line 2\n"
+            "  f();\n"
+            "} else { // else line 1\n"
+            "         // else line 2\n"
+            "         // else line 3\n"
+            "  // g line 1\n"
+            "  g();\n"
+            "}",
+            format("if (1) { // if line 1\n"
+                   "          // if line 2\n"
+                   "        // if line 3\n"
+                   "  // f line 1\n"
+                   "    // f line 2\n"
+                   "  f();\n"
+                   "} else { // else line 1\n"
+                   "        // else line 2\n"
+                   "         // else line 3\n"
+                   "  // g line 1\n"
+                   "  g();\n"
+                   "}"));
+  EXPECT_EQ("do { // line 1\n"
+            "     // line 2\n"
+            "     // line 3\n"
+            "  f();\n"
+            "} while (true);",
+            format("do { // line 1\n"
+                   "     // line 2\n"
+                   "   // line 3\n"
+                   "  f();\n"
+                   "} while (true);",
+                   getLLVMStyleWithColumns(80)));
+  EXPECT_EQ("while (a < b) { // line 1\n"
+            "  // line 2\n"
+            "  // line 3\n"
+            "  f();\n"
+            "}",
+            format("while (a < b) {// line 1\n"
+                   "  // line 2\n"
+                   "  // line 3\n"
+                   "  f();\n"
+                   "}",
+                   getLLVMStyleWithColumns(80)));
+}
+
 TEST_F(FormatTest, ReflowsComments) {
   // Break a long line and reflow with the full next line.
   EXPECT_EQ("// long long long\n"