clang-format: Add option to allow short case labels on a single line.

On a single line:
  switch (a) {
  case 1: x = 1; return;
  case 2: x = 2; return;
  default: break;
  }

Not on a single line:
  switch (a) {
  case 1:
    x = 1;
    return;
  case 2:
    x = 2;
    return;
  default:
    break;
  }

This partly addresses llvm.org/PR16535. In the long run, we probably want to
lay these out in columns.

llvm-svn: 217501

1 files changed, 42 insertions, 0 deletions

diff --git a/clang/unittests/Format/FormatTest.cpp b/clang/unittests/Format/FormatTest.cpp
index 6f00acf38f3..8b8aaf1b4a6 100644
--- a/clang/unittests/Format/FormatTest.cpp
+++ b/clang/unittests/Format/FormatTest.cpp
@@ -700,6 +700,47 @@ TEST_F(FormatTest, CaseRanges) {
                "}");
 }
 
+TEST_F(FormatTest, ShortCaseLabels) {
+  FormatStyle Style = getLLVMStyle();
+  Style.AllowShortCaseLabelsOnASingleLine = true;
+  verifyFormat("switch (a) {\n"
+               "case 1: x = 1; break;\n"
+               "case 2: return;\n"
+               "case 3:\n"
+               "case 4:\n"
+               "case 5: return;\n"
+               "default: y = 1; break;\n"
+               "}",
+               Style);
+  verifyFormat("switch (a) {\n"
+               "case 1: {\n"
+               "}\n"
+               "case 2: {\n"
+               "  return;\n"
+               "}\n"
+               "case 3: {\n"
+               "  x = 1;\n"
+               "  return;\n"
+               "}\n"
+               "case 4:\n"
+               "  if (x)\n"
+               "    return;\n"
+               "}",
+               Style);
+  Style.ColumnLimit = 21;
+  verifyFormat("switch (a) {\n"
+               "case 1: x = 1; break;\n"
+               "case 2: return;\n"
+               "case 3:\n"
+               "case 4:\n"
+               "case 5: return;\n"
+               "default:\n"
+               "  y = 1;\n"
+               "  break;\n"
+               "}",
+               Style);
+}
+
 TEST_F(FormatTest, FormatsLabels) {
   verifyFormat("void f() {\n"
                "  some_code();\n"
@@ -8316,6 +8357,7 @@ TEST_F(FormatTest, ParsesConfigurationBools) {
   CHECK_PARSE_BOOL(AlignTrailingComments);
   CHECK_PARSE_BOOL(AllowAllParametersOfDeclarationOnNextLine);
   CHECK_PARSE_BOOL(AllowShortBlocksOnASingleLine);
+  CHECK_PARSE_BOOL(AllowShortCaseLabelsOnASingleLine);
   CHECK_PARSE_BOOL(AllowShortIfStatementsOnASingleLine);
   CHECK_PARSE_BOOL(AllowShortLoopsOnASingleLine);
   CHECK_PARSE_BOOL(AlwaysBreakAfterDefinitionReturnType);