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, 1 insertions, 1 deletions

diff --git a/clang/lib/Serialization/ASTWriter.cpp b/clang/lib/Serialization/ASTWriter.cpp
index 5508b6eceac..0b257a4a1b0 100644
--- a/clang/lib/Serialization/ASTWriter.cpp
+++ b/clang/lib/Serialization/ASTWriter.cpp
@@ -281,7 +281,7 @@ void ASTTypeWriter::VisitUnaryTransformType(const UnaryTransformType *T) {
 
 void ASTTypeWriter::VisitAutoType(const AutoType *T) {
   Writer.AddTypeRef(T->getDeducedType(), Record);
-  Record.push_back(T->isDecltypeAuto());
+  Record.push_back((unsigned)T->getKeyword());
   if (T->getDeducedType().isNull())
     Record.push_back(T->isDependentType());
   Code = TYPE_AUTO;