clang-format: Support `if CONSTEXPR` if CONSTEXPR is a macro.

This is like r305666 (which added support for `if constexpr`) except
that it allows a macro name after the if.

This is slightly tricky for two reasons:

1. r305666 didn't add test coverage for all cases where it added a
   kw_constexpr, so I had to figure out what all the added cases were
   for. I now added tests for all `if constexpr` bits that didn't have
   tests. (This took a while, see e.g. https://reviews.llvm.org/D65223)

2. Parsing `if <ident> (` as an if means that `#if defined(` and
   `#if __has_include(` parse as ifs too. Add some special-case code
   to prevent this from happening where it's incorrect.

Fixes PR39248.

Differential Revision: https://reviews.llvm.org/D65227

llvm-svn: 367167

1 files changed, 8 insertions, 7 deletions

diff --git a/clang/lib/Format/TokenAnnotator.cpp b/clang/lib/Format/TokenAnnotator.cpp
index c5b9fbdae16..6e0369f27e7 100644
--- a/clang/lib/Format/TokenAnnotator.cpp
+++ b/clang/lib/Format/TokenAnnotator.cpp
@@ -175,9 +175,9 @@ private:
       Contexts.back().IsExpression = false;
     } else if (Left->Previous &&
                (Left->Previous->isOneOf(tok::kw_static_assert, tok::kw_decltype,
-                                        tok::kw_if, tok::kw_while, tok::l_paren,
+                                        tok::kw_while, tok::l_paren,
                                         tok::comma) ||
-                Left->Previous->endsSequence(tok::kw_constexpr, tok::kw_if) ||
+                Left->Previous->isIf() ||
                 Left->Previous->is(TT_BinaryOperator))) {
       // static_assert, if and while usually contain expressions.
       Contexts.back().IsExpression = true;
@@ -825,8 +825,9 @@ private:
       break;
     case tok::kw_if:
     case tok::kw_while:
+      assert(!Line.startsWith(tok::hash));
       if (Tok->is(tok::kw_if) && CurrentToken &&
-          CurrentToken->is(tok::kw_constexpr))
+          CurrentToken->isOneOf(tok::kw_constexpr, tok::identifier))
         next();
       if (CurrentToken && CurrentToken->is(tok::l_paren)) {
         next();
@@ -1078,6 +1079,7 @@ private:
     case tok::pp_if:
     case tok::pp_elif:
       Contexts.back().IsExpression = true;
+      next();
       parseLine();
       break;
     default:
@@ -2409,8 +2411,7 @@ unsigned TokenAnnotator::splitPenalty(const AnnotatedLine &Line,
       Style.AlignAfterOpenBracket != FormatStyle::BAS_DontAlign)
     return 100;
   if (Left.is(tok::l_paren) && Left.Previous &&
-      (Left.Previous->isOneOf(tok::kw_if, tok::kw_for) ||
-       Left.Previous->endsSequence(tok::kw_constexpr, tok::kw_if)))
+      (Left.Previous->is(tok::kw_for) || Left.Previous->isIf()))
     return 1000;
   if (Left.is(tok::equal) && InFunctionDecl)
     return 110;
@@ -2611,10 +2612,10 @@ bool TokenAnnotator::spaceRequiredBetween(const AnnotatedLine &Line,
       return true;
     return Line.Type == LT_ObjCDecl || Left.is(tok::semi) ||
            (Style.SpaceBeforeParens != FormatStyle::SBPO_Never &&
-            (Left.isOneOf(tok::kw_if, tok::pp_elif, tok::kw_for, tok::kw_while,
+            (Left.isOneOf(tok::pp_elif, tok::kw_for, tok::kw_while,
                           tok::kw_switch, tok::kw_case, TT_ForEachMacro,
                           TT_ObjCForIn) ||
-             Left.endsSequence(tok::kw_constexpr, tok::kw_if) ||
+             Left.isIf(Line.Type != LT_PreprocessorDirective) ||
              (Left.isOneOf(tok::kw_try, Keywords.kw___except, tok::kw_catch,
                            tok::kw_new, tok::kw_delete) &&
               (!Left.Previous || Left.Previous->isNot(tok::period))))) ||