From a03ab10f0e4d888139b3b694dd55d176982f72a4 Mon Sep 17 00:00:00 2001
From: Daniel Jasper <djasper@google.com>
Date: Wed, 13 Feb 2013 20:33:44 +0000
Subject: [PATCH] Allow breaking after the return type in function
 declarations.

This has so far been disabled for Google style, but should be done
before breaking at nested name specifiers or in template parameters.

Before (in Google style):
template <typename T>
aaaaaaaa::aaaaa::aaaaaa<T, aaaaaaaaaaaaaaaaaaaaaaaaa> aaaaaaaaaaaaaaaaaaaaaaaa<
    T>::aaaaaaa() {}

After:
template <typename T>
aaaaaaaa::aaaaa::aaaaaa<T, aaaaaaaaaaaaaaaaaaaaaaaaa>
aaaaaaaaaaaaaaaaaaaaaaaa<T>::aaaaaaa() {}

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@175074 91177308-0d34-0410-b5e6-96231b3b80d8
---
 include/clang/Format/Format.h   |  5 +++--
 lib/Format/Format.cpp           | 11 ++++++-----
 lib/Format/TokenAnnotator.cpp   |  4 +++-
 unittests/Format/FormatTest.cpp |  8 ++++++++
 4 files changed, 20 insertions(+), 8 deletions(-)

diff --git a/include/clang/Format/Format.h b/include/clang/Format/Format.h
index 75b809baab9..d6cc114e3cd 100644
--- a/include/clang/Format/Format.h
+++ b/include/clang/Format/Format.h
@@ -77,8 +77,9 @@ struct FormatStyle {
   /// the next line even if \c BinPackParameters is \c false.
   bool AllowAllParametersOfDeclarationOnNextLine;
 
-  /// \brief Allow putting the return type of a function onto its own line.
-  bool AllowReturnTypeOnItsOwnLine;
+  /// \brief Penalty for putting the return type of a function onto its own
+  /// line.
+  unsigned PenaltyReturnTypeOnItsOwnLine;
 
   /// \brief If the constructor initializers don't fit on a line, put each
   /// initializer on its own line.
diff --git a/lib/Format/Format.cpp b/lib/Format/Format.cpp
index d8c02e2e18b..8c2128eb018 100644
--- a/lib/Format/Format.cpp
+++ b/lib/Format/Format.cpp
@@ -43,11 +43,11 @@ FormatStyle getLLVMStyle() {
   LLVMStyle.SpacesBeforeTrailingComments = 1;
   LLVMStyle.BinPackParameters = true;
   LLVMStyle.AllowAllParametersOfDeclarationOnNextLine = true;
-  LLVMStyle.AllowReturnTypeOnItsOwnLine = true;
   LLVMStyle.ConstructorInitializerAllOnOneLineOrOnePerLine = false;
   LLVMStyle.AllowShortIfStatementsOnASingleLine = false;
   LLVMStyle.ObjCSpaceBeforeProtocolList = true;
   LLVMStyle.PenaltyExcessCharacter = 1000000;
+  LLVMStyle.PenaltyReturnTypeOnItsOwnLine = 5;
   return LLVMStyle;
 }
 
@@ -63,11 +63,11 @@ FormatStyle getGoogleStyle() {
   GoogleStyle.SpacesBeforeTrailingComments = 2;
   GoogleStyle.BinPackParameters = false;
   GoogleStyle.AllowAllParametersOfDeclarationOnNextLine = true;
-  GoogleStyle.AllowReturnTypeOnItsOwnLine = false;
   GoogleStyle.ConstructorInitializerAllOnOneLineOrOnePerLine = true;
   GoogleStyle.AllowShortIfStatementsOnASingleLine = false;
   GoogleStyle.ObjCSpaceBeforeProtocolList = false;
   GoogleStyle.PenaltyExcessCharacter = 1000000;
+  GoogleStyle.PenaltyReturnTypeOnItsOwnLine = 100;
   return GoogleStyle;
 }
 
@@ -717,9 +717,10 @@ private:
     reconstructPath(State, Current->Previous);
     DEBUG({
       if (Current->NewLine) {
-        llvm::errs() << "Penalty for splitting before "
-                     << Current->State.NextToken->FormatTok.Tok.getName()
-                     << ": " << Current->State.NextToken->SplitPenalty << "\n";
+        llvm::errs()
+            << "Penalty for splitting before "
+            << Current->Previous->State.NextToken->FormatTok.Tok.getName()
+            << ": " << Current->Previous->State.NextToken->SplitPenalty << "\n";
       }
     });
     addTokenToState(Current->NewLine, false, State);
diff --git a/lib/Format/TokenAnnotator.cpp b/lib/Format/TokenAnnotator.cpp
index d2e19af56f1..4c365361040 100644
--- a/lib/Format/TokenAnnotator.cpp
+++ b/lib/Format/TokenAnnotator.cpp
@@ -847,6 +847,8 @@ unsigned TokenAnnotator::splitPenalty(const AnnotatedLine &Line,
   const AnnotatedToken &Left = *Tok.Parent;
   const AnnotatedToken &Right = Tok;
 
+  if (Right.Type == TT_StartOfName)
+    return Style.PenaltyReturnTypeOnItsOwnLine;
   if (Left.is(tok::l_brace) && Right.isNot(tok::l_brace))
     return 50;
   if (Left.is(tok::equal) && Right.is(tok::l_brace))
@@ -1026,7 +1028,7 @@ bool TokenAnnotator::spaceRequiredBefore(const AnnotatedLine &Line,
 bool TokenAnnotator::canBreakBefore(const AnnotatedLine &Line,
                                     const AnnotatedToken &Right) {
   const AnnotatedToken &Left = *Right.Parent;
-  if (Right.Type == TT_StartOfName && Style.AllowReturnTypeOnItsOwnLine)
+  if (Right.Type == TT_StartOfName)
     return true;
   if (Right.is(tok::colon) && Right.Type == TT_ObjCMethodExpr)
     return false;
diff --git a/unittests/Format/FormatTest.cpp b/unittests/Format/FormatTest.cpp
index 8fb4b2acd5e..f72aad7aad6 100644
--- a/unittests/Format/FormatTest.cpp
+++ b/unittests/Format/FormatTest.cpp
@@ -1763,6 +1763,14 @@ TEST_F(FormatTest, BreaksFunctionDeclarations) {
   verifyGoogleFormat(
       "TypeSpecDecl* TypeSpecDecl::Create(\n"
       "    ASTContext& C, DeclContext* DC, SourceLocation L) {\n}");
+  verifyGoogleFormat(
+      "some_namespace::LongReturnType\n"
+      "long_namespace::SomeVeryLongClass::SomeVeryLongFunction(\n"
+      "    int first_long_parameter, int second_parameter) {\n}");
+
+  verifyGoogleFormat("template <typename T>\n"
+                     "aaaaaaaa::aaaaa::aaaaaa<T, aaaaaaaaaaaaaaaaaaaaaaaaa>\n"
+                     "aaaaaaaaaaaaaaaaaaaaaaaa<T>::aaaaaaa() {\n}");
 }
 
 TEST_F(FormatTest, LineStartsWithSpecialCharacter) {
-- 
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