Revert r197496, as it broke REVERTIBLE_TYPE_TRAITs from PCH files.

Also add a test to make sure that this doesn't break again. Fixes PR21036.

llvm-svn: 218292

1 files changed, 25 insertions, 11 deletions

diff --git a/clang/lib/Parse/ParseDeclCXX.cpp b/clang/lib/Parse/ParseDeclCXX.cpp
index b252ed5865c..8ea53966946 100644
--- a/clang/lib/Parse/ParseDeclCXX.cpp
+++ b/clang/lib/Parse/ParseDeclCXX.cpp
@@ -1226,17 +1226,31 @@ void Parser::ParseClassSpecifier(tok::TokenKind TagTokKind,
   // C++11 attributes
   SourceLocation AttrFixitLoc = Tok.getLocation();
 
-  // GNU libstdc++ and libc++ use certain intrinsic names as the
-  // name of struct templates, but some are keywords in GCC >= 4.3
-  // MSVC and Clang. For compatibility, convert the token to an identifier
-  // and issue a warning diagnostic.
-  if (TagType == DeclSpec::TST_struct && !Tok.is(tok::identifier) &&
-      !Tok.isAnnotation()) {
-    const IdentifierInfo *II = Tok.getIdentifierInfo();
-    // We rarely end up here so the following check is efficient.
-    if (II && II->getName().startswith("__is_"))
-      TryKeywordIdentFallback(true);
-  }
+  if (TagType == DeclSpec::TST_struct &&
+      !Tok.is(tok::identifier) &&
+      Tok.getIdentifierInfo() &&
+      (Tok.is(tok::kw___is_arithmetic) ||
+       Tok.is(tok::kw___is_convertible) ||
+       Tok.is(tok::kw___is_empty) ||
+       Tok.is(tok::kw___is_floating_point) ||
+       Tok.is(tok::kw___is_function) ||
+       Tok.is(tok::kw___is_fundamental) ||
+       Tok.is(tok::kw___is_integral) ||
+       Tok.is(tok::kw___is_member_function_pointer) ||
+       Tok.is(tok::kw___is_member_pointer) ||
+       Tok.is(tok::kw___is_pod) ||
+       Tok.is(tok::kw___is_pointer) ||
+       Tok.is(tok::kw___is_same) ||
+       Tok.is(tok::kw___is_scalar) ||
+       Tok.is(tok::kw___is_signed) ||
+       Tok.is(tok::kw___is_unsigned) ||
+       Tok.is(tok::kw___is_void)))
+    // GNU libstdc++ 4.2 and libc++ use certain intrinsic names as the
+    // name of struct templates, but some are keywords in GCC >= 4.3
+    // and Clang. Therefore, when we see the token sequence "struct
+    // X", make X into a normal identifier rather than a keyword, to
+    // allow libstdc++ 4.2 and libc++ to work properly.
+    TryKeywordIdentFallback(true);
 
   // Parse the (optional) nested-name-specifier.
   CXXScopeSpec &SS = DS.getTypeSpecScope();