clang-format: add option to merge empty function body

Summary:
This option supplements the AllowShortFunctionsOnASingleLine flag, to
merge empty function body at the beginning of the line: e.g. when the
function is not short-enough and breaking braces after function.

  int f()
  {}

Reviewers: krasimir, djasper

Reviewed By: djasper

Subscribers: klimek, cfe-commits

Differential Revision: https://reviews.llvm.org/D33447

llvm-svn: 305272

1 files changed, 125 insertions, 0 deletions

diff --git a/clang/unittests/Format/FormatTest.cpp b/clang/unittests/Format/FormatTest.cpp
index 64e963db4cf..783fe450427 100644
--- a/clang/unittests/Format/FormatTest.cpp
+++ b/clang/unittests/Format/FormatTest.cpp
@@ -6239,6 +6239,35 @@ TEST_F(FormatTest, PullTrivialFunctionDefinitionsIntoSingleLine) {
                getLLVMStyleWithColumns(23));
 }
 
+TEST_F(FormatTest, PullEmptyFunctionDefinitionsIntoSingleLine) {
+  FormatStyle MergeEmptyOnly = getLLVMStyle();
+  MergeEmptyOnly.AllowShortFunctionsOnASingleLine = FormatStyle::SFS_Empty;
+  verifyFormat("class C {\n"
+               "  int f() {}\n"
+               "};",
+               MergeEmptyOnly);
+  verifyFormat("class C {\n"
+               "  int f() {\n"
+               "    return 42;\n"
+               "  }\n"
+               "};",
+               MergeEmptyOnly);
+  verifyFormat("int f() {}", MergeEmptyOnly);
+  verifyFormat("int f() {\n"
+               "  return 42;\n"
+               "}",
+               MergeEmptyOnly);
+
+  // Also verify behavior when BraceWrapping.AfterFunction = true
+  MergeEmptyOnly.BreakBeforeBraces = FormatStyle::BS_Custom;
+  MergeEmptyOnly.BraceWrapping.AfterFunction = true;
+  verifyFormat("int f() {}", MergeEmptyOnly);
+  verifyFormat("class C {\n"
+               "  int f() {}\n"
+               "};",
+               MergeEmptyOnly);
+}
+
 TEST_F(FormatTest, PullInlineFunctionDefinitionsIntoSingleLine) {
   FormatStyle MergeInlineOnly = getLLVMStyle();
   MergeInlineOnly.AllowShortFunctionsOnASingleLine = FormatStyle::SFS_Inline;
@@ -6250,6 +6279,101 @@ TEST_F(FormatTest, PullInlineFunctionDefinitionsIntoSingleLine) {
                "  return 42;\n"
                "}",
                MergeInlineOnly);
+
+  // SFS_Inline implies SFS_Empty
+  verifyFormat("class C {\n"
+               "  int f() {}\n"
+               "};",
+               MergeInlineOnly);
+  verifyFormat("int f() {}", MergeInlineOnly);
+
+  // Also verify behavior when BraceWrapping.AfterFunction = true
+  MergeInlineOnly.BreakBeforeBraces = FormatStyle::BS_Custom;
+  MergeInlineOnly.BraceWrapping.AfterFunction = true;
+  verifyFormat("class C {\n"
+               "  int f() { return 42; }\n"
+               "};",
+               MergeInlineOnly);
+  verifyFormat("int f()\n"
+               "{\n"
+               "  return 42;\n"
+               "}",
+               MergeInlineOnly);
+
+  // SFS_Inline implies SFS_Empty
+  verifyFormat("int f() {}", MergeInlineOnly);
+  verifyFormat("class C {\n"
+               "  int f() {}\n"
+               "};",
+               MergeInlineOnly);
+}
+
+TEST_F(FormatTest, SplitEmptyFunctionBody) {
+  FormatStyle Style = getLLVMStyle();
+  Style.AllowShortFunctionsOnASingleLine = FormatStyle::SFS_None;
+  Style.BreakBeforeBraces = FormatStyle::BS_Custom;
+  Style.BraceWrapping.AfterFunction = true;
+  Style.BraceWrapping.SplitEmptyFunctionBody = false;
+  Style.ColumnLimit = 40;
+
+  verifyFormat("int f()\n"
+               "{}",
+               Style);
+  verifyFormat("int f()\n"
+               "{\n"
+               "  return 42;\n"
+               "}",
+               Style);
+  verifyFormat("int f()\n"
+               "{\n"
+               "  // some comment\n"
+               "}",
+               Style);
+
+  Style.AllowShortFunctionsOnASingleLine = FormatStyle::SFS_Empty;
+  verifyFormat("int f() {}", Style);
+  verifyFormat("int aaaaaaaaaaaaaa(int bbbbbbbbbbbbbb)\n"
+               "{}",
+               Style);
+  verifyFormat("int f()\n"
+               "{\n"
+               "  return 0;\n"
+               "}",
+               Style);
+
+  Style.AllowShortFunctionsOnASingleLine = FormatStyle::SFS_Inline;
+  verifyFormat("class Foo {\n"
+               "  int f() {}\n"
+               "};\n",
+               Style);
+  verifyFormat("class Foo {\n"
+               "  int f() { return 0; }\n"
+               "};\n",
+               Style);
+  verifyFormat("class Foo {\n"
+               "  int aaaaaaaaaaaaaa(int bbbbbbbbbbbbbb)\n"
+               "  {}\n"
+               "};\n",
+               Style);
+  verifyFormat("class Foo {\n"
+               "  int aaaaaaaaaaaaaa(int bbbbbbbbbbbbbb)\n"
+               "  {\n"
+               "    return 0;\n"
+               "  }\n"
+               "};\n",
+               Style);
+
+  Style.AllowShortFunctionsOnASingleLine = FormatStyle::SFS_All;
+  verifyFormat("int f() {}", Style);
+  verifyFormat("int f() { return 0; }", Style);
+  verifyFormat("int aaaaaaaaaaaaaa(int bbbbbbbbbbbbbb)\n"
+               "{}",
+               Style);
+  verifyFormat("int aaaaaaaaaaaaaa(int bbbbbbbbbbbbbb)\n"
+               "{\n"
+               "  return 0;\n"
+               "}",
+               Style);
 }
 
 TEST_F(FormatTest, UnderstandContextOfRecordTypeKeywords) {
@@ -8960,6 +9084,7 @@ TEST_F(FormatTest, ParsesConfigurationBools) {
   CHECK_PARSE_NESTED_BOOL(BraceWrapping, BeforeCatch);
   CHECK_PARSE_NESTED_BOOL(BraceWrapping, BeforeElse);
   CHECK_PARSE_NESTED_BOOL(BraceWrapping, IndentBraces);
+  CHECK_PARSE_NESTED_BOOL(BraceWrapping, SplitEmptyFunctionBody);
 }
 
 #undef CHECK_PARSE_BOOL