Add support for GCC's '__auto_type' extension, per the GCC manual:

https://gcc.gnu.org/onlinedocs/gcc/Typeof.html

Differences from the GCC extension:
 * __auto_type is also permitted in C++ (but only in places where
   it could appear in C), allowing its use in headers that might
   be shared across C and C++, or used from C++98
 * __auto_type can be combined with a declarator, as with C++ auto
   (for instance, "__auto_type *p")
 * multiple variables can be declared in a single __auto_type
   declaration, with the C++ semantics (the deduced type must be
   the same in each case)

This patch also adds a missing restriction on applying typeof to
a bit-field, which GCC has historically rejected in C (due to
lack of clarity as to whether the operand should be promoted).
The same restriction also applies to __auto_type in C (in both
GCC and Clang).

This also fixes PR25449.

Patch by Nicholas Allegra!

llvm-svn: 252690

1 files changed, 4 insertions, 4 deletions

diff --git a/clang/lib/Sema/TreeTransform.h b/clang/lib/Sema/TreeTransform.h
index 12f18c7489d..ca85ad5ea91 100644
--- a/clang/lib/Sema/TreeTransform.h
+++ b/clang/lib/Sema/TreeTransform.h
@@ -848,11 +848,11 @@ public:
   /// \brief Build a new C++11 auto type.
   ///
   /// By default, builds a new AutoType with the given deduced type.
-  QualType RebuildAutoType(QualType Deduced, bool IsDecltypeAuto) {
+  QualType RebuildAutoType(QualType Deduced, AutoTypeKeyword Keyword) {
     // Note, IsDependent is always false here: we implicitly convert an 'auto'
     // which has been deduced to a dependent type into an undeduced 'auto', so
     // that we'll retry deduction after the transformation.
-    return SemaRef.Context.getAutoType(Deduced, IsDecltypeAuto, 
+    return SemaRef.Context.getAutoType(Deduced, Keyword,
                                        /*IsDependent*/ false);
   }
 
@@ -3888,7 +3888,7 @@ TreeTransform<Derived>::TransformQualifiedType(TypeLocBuilder &TLB,
         Qs.removeObjCLifetime();
         Deduced = SemaRef.Context.getQualifiedType(Deduced.getUnqualifiedType(),
                                                    Qs);
-        Result = SemaRef.Context.getAutoType(Deduced, AutoTy->isDecltypeAuto(), 
+        Result = SemaRef.Context.getAutoType(Deduced, AutoTy->getKeyword(),
                                 AutoTy->isDependentType());
         TLB.TypeWasModifiedSafely(Result);
       } else {
@@ -5091,7 +5091,7 @@ QualType TreeTransform<Derived>::TransformAutoType(TypeLocBuilder &TLB,
   QualType Result = TL.getType();
   if (getDerived().AlwaysRebuild() || NewDeduced != OldDeduced ||
       T->isDependentType()) {
-    Result = getDerived().RebuildAutoType(NewDeduced, T->isDecltypeAuto());
+    Result = getDerived().RebuildAutoType(NewDeduced, T->getKeyword());
     if (Result.isNull())
       return QualType();
   }