[clang-format] Fix bug that misses some function-like macro usages

[owenpan]

Summary

This patch fixes PR41483.

[MyDeveloperDay]

LGTM

clang/lib/Format/UnwrappedLineParser.cpp

case tok::identifier: {
       if (Style.isCpp() && FormatTok->is(TT_StatementMacro)) {
         parseStatementMacro();
         return;
       }
 
       // See if the following token should start a new unwrapped line.
       StringRef Text = FormatTok->TokenText;
       nextToken();
-      if (Line->Tokens.size() == 1 &&
-          // JS doesn't have macros, and within classes colons indicate fields,
-          // not labels.
-          Style.Language != FormatStyle::LK_JavaScript) {
+
+      // JS doesn't have macros, and within classes colons indicate fields, not
+      // labels.
+      if (Style.Language == FormatStyle::LK_JavaScript)
+        break;
+
+      TokenCount = Line->Tokens.size();
+      if (TokenCount == 1 ||
+          (TokenCount == 2 && Line->Tokens.front().Tok->is(tok::comment))) {
         if (FormatTok->Tok.is(tok::colon) && !Line->MustBeDeclaration) {
           Line->Tokens.begin()->Tok->MustBreakBefore = true;
           parseLabel();
           return;
         }
         // Recognize function-like macro usages without trailing semicolon as
         // well as free-standing macros like Q_OBJECT.
         bool FunctionLike = FormatTok->is(tok::l_paren);

clang/unittests/Format/FormatTest.cpp

TEST_F(FormatTest, MacrosWithoutTrailingSemicolon) {
   // Only if the next line can actually start an unwrapped line.
   EXPECT_EQ("SOME_WEIRD_LOG_MACRO << SomeThing;",
             format("SOME_WEIRD_LOG_MACRO\n"
                    "<< SomeThing;"));
 
   verifyFormat("VISIT_GL_CALL(GenBuffers, void, (GLsizei n, GLuint* buffers), "
                "(n, buffers))\n",
                getChromiumStyle(FormatStyle::LK_Cpp));
+
+  // See PR41483
+  EXPECT_EQ("/**/ FOO(a)\n"
+            "FOO(b)",
+            format("/**/ FOO(a)\n"
+                   "FOO(b)"));
 }
 
 TEST_F(FormatTest, MacroCallsWithoutTrailingSemicolon) {
   EXPECT_EQ("INITIALIZE_PASS_BEGIN(ScopDetection, \"polly-detect\")\n"
             "INITIALIZE_AG_DEPENDENCY(AliasAnalysis)\n"
             "INITIALIZE_PASS_DEPENDENCY(DominatorTree)\n"
             "class X {};\n"
             "INITIALIZE_PASS_END(ScopDetection, \"polly-detect\")\n"