[clan-format] detect function definitions more conservatively

[krasimir]

Summary

https://reviews.llvm.org/D105964 updated the detection of function
definitions. It had the unfortunate effect to start marking object
definitions with attribute-like macros as function definitions.

This addresses this issue.

[owenpan]

clang/lib/Format/TokenAnnotator.cpp

2485–2486

I was contemplating the above in https://reviews.llvm.org/D105964 and should have used it instead. This is probably more conservative and accurate than checking for an l_brace following the r_paren.

[krasimir]

• apply review suggestion

[krasimir]

clang/lib/Format/TokenAnnotator.cpp

2485–2486

Thank you!

Applied the suggestion. I was a bit worried that this suggestion won't work for function definitions with a trailing semicolon, but there the semicolon is not part of the same line as the function name, so all is good there. Added a few tests for this case.

[owenpan]

LGTM

clang/lib/Format/TokenAnnotator.cpp

if (Next->MatchingParen->Next &&
       Next->MatchingParen->Next->is(TT_PointerOrReference))
     return true;
   // Check for K&R C function definitions, e.g.:
   //   int f(i)
   //   {
   //     return i + 1;
   //   }
   if (Next->Next && Next->Next->is(tok::identifier) &&
-      !(Next->MatchingParen->Next && Next->MatchingParen->Next->is(tok::semi)))
+      (!Next->MatchingParen->Next ||
+       Next->MatchingParen->Next->is(tok::l_brace)))
     return true;
   for (const FormatToken *Tok = Next->Next; Tok && Tok != Next->MatchingParen;
        Tok = Tok->Next) {
     if (Tok->is(TT_TypeDeclarationParen))
       return true;
     if (Tok->isOneOf(tok::l_paren, TT_TemplateOpener) && Tok->MatchingParen) {
       Tok = Tok->MatchingParen;
       continue;

clang/unittests/Format/FormatTest.cpp

verifyFormat("int f(a, b, c);\n" // No break here.
                "int\n"             // Break here.
                "f(a, b, c)\n"      // Break here.
                "short a, b;\n"
                "float c;\n"
                "{\n"
                "  return a + b < c;\n"
                "}",
                Style);
+  // The return breaking style doesn't affect object definitions with
+  // attribute-like macros.
+  verifyFormat("Tttttttttttttttttttttttt ppppppppppppppp\n"
+               "    ABSL_GUARDED_BY(mutex) = {};",
+               getGoogleStyleWithColumns(40));
 
   Style = getGNUStyle();
 
   // Test for comments at the end of function declarations.
   verifyFormat("void\n"
                "foo (int a, /*abc*/ int b) // def\n"
                "{\n"
                "}\n",