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
diff --git a/clang/test/Sema/exprs.c b/clang/test/Sema/exprs.c
index 17b1aa2..5da4f94 100644
--- a/clang/test/Sema/exprs.c
+++ b/clang/test/Sema/exprs.c
@@ -97,6 +97,7 @@
R = __alignof(P->x); // expected-error {{invalid application of 'alignof' to bit-field}}
R = __alignof(P->y); // ok.
R = sizeof(P->x); // expected-error {{invalid application of 'sizeof' to bit-field}}
+ __extension__ ({ R = (__typeof__(P->x)) 2; }); // expected-error {{invalid application of 'typeof' to bit-field}}
return R;
}