Change clang-format's affinity for breaking after return types.

Function declarations are now broken with the following preferences:
1) break amongst arguments.
2) break after return type.
3) break after (.
4) break before after nested name specifiers.

Options #2 or #3 are preferred over #1 only if a substantial number of
lines can be saved by that.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@179287 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 56 insertions, 6 deletions

diff --git a/unittests/Format/FormatTest.cpp b/unittests/Format/FormatTest.cpp
index 09fbce830e..91b8f81080 100644
--- a/unittests/Format/FormatTest.cpp
+++ b/unittests/Format/FormatTest.cpp
@@ -1199,8 +1199,8 @@ TEST_F(FormatTest, FormatsSmallMacroDefinitionsInSingleLine) {
 
 TEST_F(FormatTest, DoesNotBreakPureVirtualFunctionDefinition) {
   verifyFormat(
-      "virtual void\n"
-      "write(ELFWriter *writerrr, OwningPtr<FileOutputBuffer> &buffer) = 0;");
+      "virtual void write(ELFWriter *writerrr,\n"
+      "                   OwningPtr<FileOutputBuffer> &buffer) = 0;");
 }
 
 TEST_F(FormatTest, LayoutUnknownPPDirective) {
@@ -1700,6 +1700,56 @@ TEST_F(FormatTest, BreaksAsHighAsPossible) {
                "    Intervals[i - 1].getRange().getLast()) {\n}");
 }
 
+TEST_F(FormatTest, BreaksFunctionDeclarations) {
+  // Principially, we break function declarations in a certain order:
+  // 1) break amongst arguments.
+  verifyFormat("Aaaaaaaaaaaaaa bbbbbbbbbbbbbb(Cccccccccccccc cccccccccccccc,\n"
+               "                              Cccccccccccccc cccccccccccccc);");
+
+  // 2) break after return type.
+  verifyFormat("Aaaaaaaaaaaaaaaaaaaaaaaa\n"
+               "bbbbbbbbbbbbbb(Cccccccccccccc cccccccccccccccccccccccccc);");
+
+  // 3) break after (.
+  verifyFormat(
+      "Aaaaaaaaaaaaaaaaaaaaaaaa bbbbbbbbbbbbbbbbbb(\n"
+      "    Cccccccccccccccccccccccccccccc cccccccccccccccccccccccccccccccc);");
+
+  // 4) break before after nested name specifiers.
+  verifyFormat(
+      "Aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa\n"
+      "SomeClasssssssssssssssssssssssssssssssssssssss::\n"
+      "    bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb(Cccccccccccccc cccccccccc);");
+
+  // However, there are exceptions, if a sufficient amount of lines can be
+  // saved.
+  // FIXME: The precise cut-offs wrt. the number of saved lines might need some
+  // more adjusting.
+  verifyFormat("Aaaaaaaaaaaaaaaaaa bbbbbbbbbbbbbb(Cccccccccccccc cccccccccc,\n"
+               "                                  Cccccccccccccc cccccccccc,\n"
+               "                                  Cccccccccccccc cccccccccc,\n"
+               "                                  Cccccccccccccc cccccccccc,\n"
+               "                                  Cccccccccccccc cccccccccc);");
+  verifyFormat(
+      "Aaaaaaaaaaaaaaaaaa\n"
+      "bbbbbbbbbbbbbb(Cccccccccccccc cccccccccc, Cccccccccccccc cccccccccc,\n"
+      "               Cccccccccccccc cccccccccc, Cccccccccccccc cccccccccc,\n"
+      "               Cccccccccccccc cccccccccc, Cccccccccccccc cccccccccc);");
+  verifyFormat(
+      "Aaaaaaaaaa bbbbbbbbbbbbbbbbbbbbbbbbbbbbbb(Cccccccccccccc cccccccccc,\n"
+      "                                          Cccccccccccccc cccccccccc,\n"
+      "                                          Cccccccccccccc cccccccccc,\n"
+      "                                          Cccccccccccccc cccccccccc,\n"
+      "                                          Cccccccccccccc cccccccccc,\n"
+      "                                          Cccccccccccccc cccccccccc,\n"
+      "                                          Cccccccccccccc cccccccccc);");
+  verifyFormat("Aaaaaaaaaa bbbbbbbbbbbbbbbbbbbbbbbbbbbbbb(\n"
+               "    Cccccccccccccc cccccccccc, Cccccccccccccc cccccccccc,\n"
+               "    Cccccccccccccc cccccccccc, Cccccccccccccc cccccccccc,\n"
+               "    Cccccccccccccc cccccccccc, Cccccccccccccc cccccccccc,\n"
+               "    Cccccccccccccc cccccccccc, Cccccccccccccc cccccccccc);");
+}
+
 TEST_F(FormatTest, BreaksDesireably) {
   verifyFormat("if (aaaaaaaaaaaaaaaaaaa(aaaaaaaaaaaaaaa) ||\n"
                "    aaaaaaaaaaaaaaaaaaa(aaaaaaaaaaaaaaa) ||\n"
@@ -1850,7 +1900,7 @@ TEST_F(FormatTest, DoesNotBreakTrailingAnnotation) {
       "                   aaaaaaaaaaaaaaaaaaaaaaaaa));");
   verifyFormat("bool aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa\n"
                "    __attribute__((unused));");
-  
+
   // FIXME: This is bad indentation, but generally hard to distinguish from a
   // function declaration.
   verifyFormat(
@@ -2600,9 +2650,9 @@ TEST_F(FormatTest, BreaksLongDeclarations) {
   verifyFormat("int *someFunction(int LoooooooooooooooooooongParam1,\n"
                "                  int LoooooooooooooooooooongParam2) {}");
   verifyFormat(
-      "TypeSpecDecl *\n"
-      "TypeSpecDecl::Create(ASTContext &C, DeclContext *DC, SourceLocation L,\n"
-      "                     IdentifierIn *II, Type *T) {}");
+      "TypeSpecDecl *TypeSpecDecl::Create(ASTContext &C, DeclContext *DC,\n"
+      "                                   SourceLocation L, IdentifierIn *II,\n"
+      "                                   Type *T) {}");
   verifyFormat("ReallyLongReturnType<TemplateParam1, TemplateParam2>\n"
                "ReallyReallyLongFunctionName(\n"
                "    const std::string &SomeParameter,\n"