To support using Control Flow Guard with mingw-w64, Clang needs to
accept `__declspec(guard(nocf))` also for the GNU target. Since mingw
has `#define __declspec(a) __attribute__((a))` as built-in, the simplest
solution is to accept `__attribute__((guard(nocf)))` to be compatible with
MSVC and Clang's msvc target.
As a side effect, this also adds `[[clang::guard(nocf)]]` for C++.
Reviewed By: aaron.ballman
Differential Revision: https://reviews.llvm.org/D132302
Summary:
Avoid using the `nocf_check` attribute with Control Flow Guard. Instead, use a
new `"guard_nocf"` function attribute to indicate that checks should not be
added on indirect calls within that function. Add support for
`__declspec(guard(nocf))` following the same syntax as MSVC.
Reviewers: rnk, dmajor, pcc, hans, aaron.ballman
Reviewed By: aaron.ballman
Subscribers: aaron.ballman, tomrittervg, hiraditya, cfe-commits, llvm-commits
Tags: #clang, #llvm
Differential Revision: https://reviews.llvm.org/D72167
Alvin Wong