clang-format: Prefer column layout if possible.

Add a severe penalty for not using column layout for braced lists. If
there are solutions with column layout, these are generally preferable
over bin-packed solutions.

Before:
  std::vector<MyValues> aaaaaaaaaaaaaaaaaaa{ aaaaaaa, aaaaaaaaaa, aaaaa,
                                             aaaaaaaaaaaaaaa, aaa, aaaaaaaaaa, a,
                                             aaaaaaaaaaaaaaaaaaaaa, aaaaaaaaaaaa,
                                             aaaaaaaaaaaaaaaaaaa +
                                                 aaaaaaaaaaaaaaaaaaa,
                                             aaaaaaa, a };
After:
  std::vector<MyValues> aaaaaaaaaaaaaaaaaaa{
    aaaaaaa,      aaaaaaaaaa,
    aaaaa,        aaaaaaaaaaaaaaa,
    aaa,          aaaaaaaaaa,
    a,            aaaaaaaaaaaaaaaaaaaaa,
    aaaaaaaaaaaa, aaaaaaaaaaaaaaaaaaa + aaaaaaaaaaaaaaaaaaa,
    aaaaaaa,      a
  };

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@195546 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/Format/FormatToken.cpp b/lib/Format/FormatToken.cpp
index 8ac704a3bb6dd0ae3cd35df02040ed2031a57c3f..bab2425205cc42de3ac7c06e5e17f910f58109a7 100644 (file)
--- a/lib/Format/FormatToken.cpp
+++ b/lib/Format/FormatToken.cpp
@@ -48,8 +48,11 @@ unsigned CommaSeparatedList::format(LineState &State,
 
   // Find the best ColumnFormat, i.e. the best number of columns to use.
   const ColumnFormat *Format = getColumnFormat(RemainingCodePoints);
+  // If no ColumnFormat can be used, the braced list would generally be
+  // bin-packed. Add a severe penalty to this so that column layouts are
+  // prefered if possible.
   if (!Format)
-    return 0;
+    return 10000;
 
   // Format the entire list.
   unsigned Penalty = 0;

diff --git a/unittests/Format/FormatTest.cpp b/unittests/Format/FormatTest.cpp
index 5ddcc3f1316ba6e5000a192ca471aa2542a89dc4..5404c49a01719896316bc3af091268c59cb039cd 100644 (file)
--- a/unittests/Format/FormatTest.cpp
+++ b/unittests/Format/FormatTest.cpp
@@ -4698,6 +4698,14 @@ TEST_F(FormatTest, LayoutCxx11ConstructorBraceInitializers) {
     verifyFormat(
         "std::this_thread::sleep_for(\n"
         "    std::chrono::nanoseconds{ std::chrono::seconds{ 1 } } / 5);");
+    verifyFormat("std::vector<MyValues> aaaaaaaaaaaaaaaaaaa{\n"
+                 "  aaaaaaa,      aaaaaaaaaa,\n"
+                 "  aaaaa,        aaaaaaaaaaaaaaa,\n"
+                 "  aaa,          aaaaaaaaaa,\n"
+                 "  a,            aaaaaaaaaaaaaaaaaaaaa,\n"
+                 "  aaaaaaaaaaaa, aaaaaaaaaaaaaaaaaaa + aaaaaaaaaaaaaaaaaaa,\n"
+                 "  aaaaaaa,      a\n"
+                 "};");
 
     FormatStyle NoSpaces = getLLVMStyle();
     NoSpaces.Cpp11BracedListStyle = true;