Implemented GNU-style formatting for compound statements.

Summary:
Added BraceBreakingStyle::BS_GNU. I'm not sure about the correctness of
static initializer formatting, but compound statements should be fine.

Reviewers: djasper

Reviewed By: djasper

CC: cfe-commits, klimek

Differential Revision: http://llvm-reviews.chandlerc.com/D2372

llvm-svn: 197138

6 files changed, 145 insertions, 26 deletions

diff --git a/clang/include/clang/Format/Format.h b/clang/include/clang/Format/Format.h
index 7af5a094511f..0b51a205021f 100644
--- a/clang/include/clang/Format/Format.h
+++ b/clang/include/clang/Format/Format.h
@@ -218,7 +218,11 @@ struct FormatStyle {
     /// Like \c Attach, but break before function definitions.
     BS_Stroustrup,
     /// Always break before braces.
-    BS_Allman
+    BS_Allman,
+    /// Always break before braces and add an extra level of indentation to
+    /// braces of control statements, not to those of class, function
+    /// or other definitions.
+    BS_GNU
   };
 
   /// \brief The brace breaking style to use.
diff --git a/clang/lib/Format/Format.cpp b/clang/lib/Format/Format.cpp
index 808e64db9155..87c2fd70aeee 100644
--- a/clang/lib/Format/Format.cpp
+++ b/clang/lib/Format/Format.cpp
@@ -68,6 +68,7 @@ template <> struct ScalarEnumerationTraits<FormatStyle::BraceBreakingStyle> {
     IO.enumCase(Value, "Linux", FormatStyle::BS_Linux);
     IO.enumCase(Value, "Stroustrup", FormatStyle::BS_Stroustrup);
     IO.enumCase(Value, "Allman", FormatStyle::BS_Allman);
+    IO.enumCase(Value, "GNU", FormatStyle::BS_GNU);
   }
 };
 
@@ -359,7 +360,7 @@ FormatStyle getWebKitStyle() {
 FormatStyle getGNUStyle() {
   FormatStyle Style = getLLVMStyle();
   Style.BreakBeforeBinaryOperators = true;
-  Style.BreakBeforeBraces = FormatStyle::BS_Allman;
+  Style.BreakBeforeBraces = FormatStyle::BS_GNU;
   Style.BreakBeforeTernaryOperators = true;
   Style.ColumnLimit = 79;
   Style.SpaceBeforeParens = FormatStyle::SBPO_Always;
@@ -561,7 +562,8 @@ private:
       SmallVectorImpl<AnnotatedLine *>::const_iterator E, unsigned Limit) {
     if (Limit == 0)
       return 0;
-    if (Style.BreakBeforeBraces == FormatStyle::BS_Allman &&
+    if ((Style.BreakBeforeBraces == FormatStyle::BS_Allman ||
+         Style.BreakBeforeBraces == FormatStyle::BS_GNU) &&
         I[1]->First->is(tok::l_brace))
       return 0;
     if (I[1]->InPPDirective != (*I)->InPPDirective ||
diff --git a/clang/lib/Format/TokenAnnotator.cpp b/clang/lib/Format/TokenAnnotator.cpp
index b8905a9bfd39..37ad7336513c 100644
--- a/clang/lib/Format/TokenAnnotator.cpp
+++ b/clang/lib/Format/TokenAnnotator.cpp
@@ -1410,7 +1410,8 @@ bool TokenAnnotator::mustBreakBefore(const AnnotatedLine &Line,
              Right.Previous->isNot(tok::r_brace) && Right.isNot(tok::r_brace)) {
     return true;
   } else if (Right.is(tok::l_brace) && (Right.BlockKind == BK_Block)) {
-    return Style.BreakBeforeBraces == FormatStyle::BS_Allman;
+    return Style.BreakBeforeBraces == FormatStyle::BS_Allman ||
+           Style.BreakBeforeBraces == FormatStyle::BS_GNU;
   }
   return false;
 }
diff --git a/clang/lib/Format/UnwrappedLineParser.cpp b/clang/lib/Format/UnwrappedLineParser.cpp
index 1eb0ae170073..089bd570b5c5 100644
--- a/clang/lib/Format/UnwrappedLineParser.cpp
+++ b/clang/lib/Format/UnwrappedLineParser.cpp
@@ -152,6 +152,27 @@ private:
   SmallVectorImpl<UnwrappedLine> *OriginalLines;
 };
 
+class CompoundStatementIndenter {
+public:
+  CompoundStatementIndenter(UnwrappedLineParser *Parser,
+                            const FormatStyle &Style, unsigned &LineLevel)
+      : LineLevel(LineLevel), OldLineLevel(LineLevel) {
+    if (Style.BreakBeforeBraces == FormatStyle::BS_Allman) {
+      Parser->addUnwrappedLine();
+    } else if (Style.BreakBeforeBraces == FormatStyle::BS_GNU) {
+      Parser->addUnwrappedLine();
+      ++LineLevel;
+    }
+  }
+  ~CompoundStatementIndenter() {
+    LineLevel = OldLineLevel;
+  }
+
+private:
+  unsigned &LineLevel;
+  unsigned OldLineLevel;
+};
+
 namespace {
 
 class IndexedTokenSource : public FormatTokenSource {
@@ -677,9 +698,7 @@ void UnwrappedLineParser::parseStructuralElement() {
         // structural element.
         // FIXME: Figure out cases where this is not true, and add projections
         // for them (the one we know is missing are lambdas).
-        if (Style.BreakBeforeBraces == FormatStyle::BS_Linux ||
-            Style.BreakBeforeBraces == FormatStyle::BS_Stroustrup ||
-            Style.BreakBeforeBraces == FormatStyle::BS_Allman)
+        if (Style.BreakBeforeBraces != FormatStyle::BS_Attach)
           addUnwrappedLine();
         FormatTok->Type = TT_FunctionLBrace;
         parseBlock(/*MustBeDeclaration=*/false);
@@ -938,13 +957,14 @@ void UnwrappedLineParser::parseIfThenElse() {
     parseParens();
   bool NeedsUnwrappedLine = false;
   if (FormatTok->Tok.is(tok::l_brace)) {
-    if (Style.BreakBeforeBraces == FormatStyle::BS_Allman)
-      addUnwrappedLine();
+    CompoundStatementIndenter Indenter(this, Style, Line->Level);
     parseBlock(/*MustBeDeclaration=*/false);
-    if (Style.BreakBeforeBraces == FormatStyle::BS_Allman)
+    if (Style.BreakBeforeBraces == FormatStyle::BS_Allman ||
+        Style.BreakBeforeBraces == FormatStyle::BS_GNU) {
       addUnwrappedLine();
-    else
+    } else {
       NeedsUnwrappedLine = true;
+    }
   } else {
     addUnwrappedLine();
     ++Line->Level;
@@ -954,8 +974,7 @@ void UnwrappedLineParser::parseIfThenElse() {
   if (FormatTok->Tok.is(tok::kw_else)) {
     nextToken();
     if (FormatTok->Tok.is(tok::l_brace)) {
-      if (Style.BreakBeforeBraces == FormatStyle::BS_Allman)
-        addUnwrappedLine();
+      CompoundStatementIndenter Indenter(this, Style, Line->Level);
       parseBlock(/*MustBeDeclaration=*/false);
       addUnwrappedLine();
     } else if (FormatTok->Tok.is(tok::kw_if)) {
@@ -978,7 +997,8 @@ void UnwrappedLineParser::parseNamespace() {
     nextToken();
   if (FormatTok->Tok.is(tok::l_brace)) {
     if (Style.BreakBeforeBraces == FormatStyle::BS_Linux ||
-        Style.BreakBeforeBraces == FormatStyle::BS_Allman)
+        Style.BreakBeforeBraces == FormatStyle::BS_Allman ||
+        Style.BreakBeforeBraces == FormatStyle::BS_GNU)
       addUnwrappedLine();
 
     bool AddLevel = Style.NamespaceIndentation == FormatStyle::NI_All ||
@@ -1001,8 +1021,7 @@ void UnwrappedLineParser::parseForOrWhileLoop() {
   if (FormatTok->Tok.is(tok::l_paren))
     parseParens();
   if (FormatTok->Tok.is(tok::l_brace)) {
-    if (Style.BreakBeforeBraces == FormatStyle::BS_Allman)
-      addUnwrappedLine();
+    CompoundStatementIndenter Indenter(this, Style, Line->Level);
     parseBlock(/*MustBeDeclaration=*/false);
     addUnwrappedLine();
   } else {
@@ -1017,9 +1036,10 @@ void UnwrappedLineParser::parseDoWhile() {
   assert(FormatTok->Tok.is(tok::kw_do) && "'do' expected");
   nextToken();
   if (FormatTok->Tok.is(tok::l_brace)) {
-    if (Style.BreakBeforeBraces == FormatStyle::BS_Allman)
-      addUnwrappedLine();
+    CompoundStatementIndenter Indenter(this, Style, Line->Level);
     parseBlock(/*MustBeDeclaration=*/false);
+    if (Style.BreakBeforeBraces == FormatStyle::BS_GNU)
+      addUnwrappedLine();
   } else {
     addUnwrappedLine();
     ++Line->Level;
@@ -1043,17 +1063,20 @@ void UnwrappedLineParser::parseLabel() {
   if (Line->Level > 1 || (!Line->InPPDirective && Line->Level > 0))
     --Line->Level;
   if (CommentsBeforeNextToken.empty() && FormatTok->Tok.is(tok::l_brace)) {
-    if (Style.BreakBeforeBraces == FormatStyle::BS_Allman)
-      addUnwrappedLine();
+    CompoundStatementIndenter Indenter(this, Style, Line->Level);
     parseBlock(/*MustBeDeclaration=*/false);
     if (FormatTok->Tok.is(tok::kw_break)) {
-      // "break;" after "}" on its own line only for BS_Allman
-      if (Style.BreakBeforeBraces == FormatStyle::BS_Allman)
+      // "break;" after "}" on its own line only for BS_Allman and BS_GNU
+      if (Style.BreakBeforeBraces == FormatStyle::BS_Allman ||
+          Style.BreakBeforeBraces == FormatStyle::BS_GNU) {
         addUnwrappedLine();
+      }
       parseStructuralElement();
     }
+    addUnwrappedLine();
+  } else {
+    addUnwrappedLine();
   }
-  addUnwrappedLine();
   Line->Level = OldLineLevel;
 }
 
@@ -1072,8 +1095,7 @@ void UnwrappedLineParser::parseSwitch() {
   if (FormatTok->Tok.is(tok::l_paren))
     parseParens();
   if (FormatTok->Tok.is(tok::l_brace)) {
-    if (Style.BreakBeforeBraces == FormatStyle::BS_Allman)
-      addUnwrappedLine();
+    CompoundStatementIndenter Indenter(this, Style, Line->Level);
     parseBlock(/*MustBeDeclaration=*/false);
     addUnwrappedLine();
   } else {
@@ -1164,7 +1186,8 @@ void UnwrappedLineParser::parseRecord() {
   }
   if (FormatTok->Tok.is(tok::l_brace)) {
     if (Style.BreakBeforeBraces == FormatStyle::BS_Linux ||
-        Style.BreakBeforeBraces == FormatStyle::BS_Allman)
+        Style.BreakBeforeBraces == FormatStyle::BS_Allman ||
+        Style.BreakBeforeBraces == FormatStyle::BS_GNU)
       addUnwrappedLine();
 
     parseBlock(/*MustBeDeclaration=*/true, /*Addlevel=*/true,
diff --git a/clang/lib/Format/UnwrappedLineParser.h b/clang/lib/Format/UnwrappedLineParser.h
index f1f4e57a20b3..71caed8505c1 100644
--- a/clang/lib/Format/UnwrappedLineParser.h
+++ b/clang/lib/Format/UnwrappedLineParser.h
@@ -185,6 +185,7 @@ private:
   std::stack<int> PPChainBranchIndex;
 
   friend class ScopedLineState;
+  friend class CompoundStatementIndenter;
 };
 
 struct UnwrappedLineNode {
diff --git a/clang/unittests/Format/FormatTest.cpp b/clang/unittests/Format/FormatTest.cpp
index 91519d8dad86..940f60df3c48 100644
--- a/clang/unittests/Format/FormatTest.cpp
+++ b/clang/unittests/Format/FormatTest.cpp
@@ -6935,6 +6935,91 @@ TEST_F(FormatTest, AllmanBraceBreaking) {
                BreakBeforeBraceShortIfs);
 }
 
+TEST_F(FormatTest, GNUBraceBreaking) {
+  FormatStyle GNUBraceStyle = getLLVMStyle();
+  GNUBraceStyle.BreakBeforeBraces = FormatStyle::BS_GNU;
+  verifyFormat("namespace a\n"
+               "{\n"
+               "class A\n"
+               "{\n"
+               "  void f()\n"
+               "  {\n"
+               "    int a;\n"
+               "    {\n"
+               "      int b;\n"
+               "    }\n"
+               "    if (true)\n"
+               "      {\n"
+               "        a();\n"
+               "        b();\n"
+               "      }\n"
+               "  }\n"
+               "  void g() { return; }\n"
+               "}\n"
+               "}",
+               GNUBraceStyle);
+
+  verifyFormat("void f()\n"
+               "{\n"
+               "  if (true)\n"
+               "    {\n"
+               "      a();\n"
+               "    }\n"
+               "  else if (false)\n"
+               "    {\n"
+               "      b();\n"
+               "    }\n"
+               "  else\n"
+               "    {\n"
+               "      c();\n"
+               "    }\n"
+               "}\n",
+               GNUBraceStyle);
+
+  verifyFormat("void f()\n"
+               "{\n"
+               "  for (int i = 0; i < 10; ++i)\n"
+               "    {\n"
+               "      a();\n"
+               "    }\n"
+               "  while (false)\n"
+               "    {\n"
+               "      b();\n"
+               "    }\n"
+               "  do\n"
+               "    {\n"
+               "      c();\n"
+               "    }\n"
+               "  while (false);\n"
+               "}\n",
+               GNUBraceStyle);
+
+  verifyFormat("void f(int a)\n"
+               "{\n"
+               "  switch (a)\n"
+               "    {\n"
+               "    case 0:\n"
+               "      break;\n"
+               "    case 1:\n"
+               "      {\n"
+               "        break;\n"
+               "      }\n"
+               "    case 2:\n"
+               "      {\n"
+               "      }\n"
+               "      break;\n"
+               "    default:\n"
+               "      break;\n"
+               "    }\n"
+               "}\n",
+               GNUBraceStyle);
+
+  verifyFormat("enum X\n"
+               "{\n"
+               "  Y = 0,\n"
+               "}\n",
+               GNUBraceStyle);
+}
 TEST_F(FormatTest, CatchExceptionReferenceBinding) {
   verifyFormat("void f() {\n"
                "  try {\n"
@@ -7132,6 +7217,9 @@ TEST_F(FormatTest, ParsesConfiguration) {
               FormatStyle::BS_Linux);
   CHECK_PARSE("BreakBeforeBraces: Stroustrup", BreakBeforeBraces,
               FormatStyle::BS_Stroustrup);
+  CHECK_PARSE("BreakBeforeBraces: Allman", BreakBeforeBraces,
+              FormatStyle::BS_Allman);
+  CHECK_PARSE("BreakBeforeBraces: GNU", BreakBeforeBraces, FormatStyle::BS_GNU);
 
   Style.NamespaceIndentation = FormatStyle::NI_All;
   CHECK_PARSE("NamespaceIndentation: None", NamespaceIndentation,