The C and C++ standards require the argument to __has_cpp_attribute and
__has_c_attribute to be expanded ([cpp.cond]p5). It would make little sense
to expand the argument to those operators but not expand the argument to
__has_attribute and __has_declspec, so those were both also changed in this
patch.
Note that it might make sense for the other builtins to also expand their
argument, but it wasn't as clear to me whether the behavior would be correct
there, and so they were left for a future revision.
This implements the likelihood attribute for the switch statement. Based on the
discussion in D85091 and D86559 it only handles the attribute when placed on
the case labels or the default labels.
It also marks the likelihood attribute as feature complete. There are more QoI
patches in the pipeline.
Differential Revision: https://reviews.llvm.org/D89210
This is the initial part of the implementation of the C++20 likelihood
attributes. It handles the attributes in an if statement.
Differential Revision: https://reviews.llvm.org/D85091
This gives library implementers a way to use standards-based attributes that do not conflict with user-defined macros of the same name. Attributes in C2x require this behavior normatively (C2x 6.7.11p4), but there's no reason to not have the same behavior in C++, especially given that such attributes may be used by a C library consumed by a C++ compilation.
llvm-svn: 369033
As passed in the Cologne meeting and treated by Core as a DR,
[[nodiscard]] was applied to constructors so that they can be diagnosed
in cases where the user forgets a variable name for a type.
The intent is to enable the library to start using this on the
constructors of scope_guard/lock_guard.
Differential Revision: https://reviews.llvm.org/D64914
llvm-svn: 367027
Currently, we only accept clang as the scoped attribute identifier for double square bracket attributes provided by Clang, but this has the potential to conflict with user-defined macros. To help alleviate these concerns, this introduces the _Clang scoped attribute identifier as an alias for clang. It also introduces a warning with a fixit on the off chance someone attempts to use __clang__ as the scoped attribute (which is a predefined compiler identification macro).
llvm-svn: 346521
Aaron Ballman