[clang-format] Allow custom attributes in access specifiers

[eoanermine]

Summary

• Allow custom attributes in access specifiers
• Add tests for custom attributes in access specifiers
• Add more tests for correct handling of Qt's signals and slots

Fixes https://github.com/llvm/llvm-project/issues/37751

[curdeius]

clang/unittests/Format/FormatTest.cpp

3304

How about multiple macros?
E.g. public ATTR1 ATTR2?

[curdeius]

clang/unittests/Format/FormatTest.cpp

3298

In the same vein, could you add test for slots: and Q_SLOTS: please?

clang/lib/Format/UnwrappedLineFormatter.cpp

int getIndentOffset(const FormatToken &RootToken) {
     }
 
     auto IsAccessModifier = [this, &RootToken]() {
       if (RootToken.isAccessSpecifier(Style.isCpp())) {
         return true;
       } else if (RootToken.isObjCAccessSpecifier()) {
         return true;
       }
-      // Handle Qt signals.
-      else if ((RootToken.isOneOf(Keywords.kw_signals, Keywords.kw_qsignals) &&
-                RootToken.Next && RootToken.Next->is(tok::colon))) {
+      // Handle Qt signals and custom attributes.
+      else if (RootToken.isOneOf(Keywords.kw_signals, Keywords.kw_qsignals) &&
+               RootToken.Next && RootToken.Next->is(tok::colon)) {
         return true;
-      } else if (RootToken.Next &&
-                 RootToken.Next->isOneOf(Keywords.kw_slots,
-                                         Keywords.kw_qslots) &&
+      } else if (RootToken.isAccessSpecifier(/*colonRequired=*/false) &&
+                 RootToken.Next &&
+                 RootToken.Next->isOneOf(Keywords.kw_slots, Keywords.kw_qslots,
+                                         tok::identifier) &&
                  RootToken.Next->Next && RootToken.Next->Next->is(tok::colon)) {
         return true;
       }
       // Handle malformed access specifier e.g. 'private' without trailing ':'.
       else if (!RootToken.Next && RootToken.isAccessSpecifier(false)) {
         return true;
       }
       return false;

clang/lib/Format/UnwrappedLineParser.cpp

 }
 
 void UnwrappedLineParser::parseAccessSpecifier() {
   FormatToken *AccessSpecifierCandidate = FormatTok;
   nextToken();
   // Understand Qt's slots.
   if (FormatTok->isOneOf(Keywords.kw_slots, Keywords.kw_qslots))
     nextToken();
+  // Handle custom attributes.
+  if (FormatTok->is(tok::identifier) && Tokens->peekNextToken()->is(tok::colon))
+    nextToken();
+
   // Otherwise, we don't know what it is, and we'd better keep the next token.
   if (FormatTok->is(tok::colon)) {
     nextToken();
     addUnwrappedLine();
   } else if (!FormatTok->is(tok::coloncolon) &&
              !isCOperatorFollowingVar(FormatTok->Tok.getKind())) {
     // Not a variable name nor namespace name.
     addUnwrappedLine();

clang/unittests/Format/FormatTest.cpp

verifyFormat("class A {\n"
                "protected slots:\n"
                "  void f3() {}\n"
                "protected Q_SLOTS:\n"
                "  void f4() {}\n"
                "private slots:\n"
                "  void f5() {}\n"
                "private Q_SLOTS:\n"
                "  void f6() {}\n"
                "signals:\n"
                "  void g1();\n"
                "Q_SIGNALS:\n"
                "  void g2();\n"
                "};");
+  verifyFormat("class A {\n"
+               "public ATTR:\n"
+               "  void f1() {}\n"
+               "protected ATTR:\n"
+               "  void f2() {}\n"
+               "private ATTR:\n"
+               "  void f3() {}\n"
+               "};");
 
   // Don't interpret 'signals' the wrong way.
+  verifyFormat("struct Bitfields {\n"
+               "  unsigned signals : 1;\n"
+               "};");
   verifyFormat("signals.set();");
   verifyFormat("for (Signals signals : f()) {\n}");
   verifyFormat("{\n"
                "  signals.set(); // This needs indentation.\n"
                "}");
   verifyFormat("void f() {\n"
                "label:\n"
                "  signals.baz();\n"
                "}");
+
+  // Don't interpret 'slots' the wrong way.
+  verifyFormat("struct Bitfields {\n"
+               "  unsigned slots : 1;\n"
+               "};");
+  verifyFormat("slots.set();");
+  verifyFormat("for (Signals slots : f()) {\n}");
+  verifyFormat("{\n"
+               "  slots.set(); // This needs indentation.\n"
+               "}");
+  verifyFormat("void f() {\n"
+               "label:\n"
+               "  slots.baz();\n"
+               "}");
+
   verifyFormat("private[1];");
   verifyFormat("testArray[public] = 1;");
   verifyFormat("public();");
   verifyFormat("myFunc(public);");
   verifyFormat("std::vector<int> testVec = {private};");
   verifyFormat("private.p = 1;");
   verifyFormat("void function(private...){};");
   verifyFormat("if (private && public)\n");