- Add atomic-to/from-nonatomic cast types
- Emit atomic operations for arithmetic on atomic types
- Emit non-atomic stores for initialisation of atomic types, but atomic stores and loads for every other store / load
- Add a __atomic_init() intrinsic which does a non-atomic store to an _Atomic() type. This is needed for the corresponding C11 stdatomic.h function.
- Enables the relevant __has_feature() checks. The feature isn't 100% complete yet, but it's done enough that we want people testing it.
Still to do:
- Make the arithmetic operations on atomic types (e.g. Atomic(int) foo = 1; foo++;) use the correct LLVM intrinsic if one exists, not a loop with a cmpxchg.
- Add a signal fence builtin
- Properly set the fenv state in atomic operations on floating point values
- Correctly handle things like _Atomic(_Complex double) which are too large for an atomic cmpxchg on some platforms (this requires working out what 'correctly' means in this context)
- Fix the many remaining corner cases
llvm-svn: 148242
__has_extension is a function-like macro which takes the same set
of feature identifiers as __has_feature. It evaluates to 1 if the
feature is supported by Clang in the current language (either as a
language extension or a standard language feature) or 0 if not.
At the same time, add support for the C1X feature identifiers
c_generic_selections (renamed from generic_selections) and
c_static_assert, and document them.
Patch by myself and Jean-Daniel Dupas.
llvm-svn: 131308
David Chisnall