Separate out the tests for whether the compiler suports R-value

references from whether it supports an R-value reference *this. No
version of GCC today supports the latter, which breaks GCC C++11
compiles of LLVM and Clang now.

Also add doxygen comments clarifying what's going on here, and update
the usage in Optional. I'll update the usages in Clang next.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@168993 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Chandler Carruth 2012-11-30 11:04:18 +00:00
parent 58b4553549
commit a5bf44b0b3
2 changed files with 15 additions and 3 deletions

View File

@ -55,7 +55,7 @@ public:
const T* operator->() const { return getPointer(); }
const T& operator*() const LLVM_LVALUE_FUNCTION { assert(hasVal); return x; }
#if LLVM_USE_RVALUE_REFERENCES
#if LLVM_HAS_RVALUE_REFERENCE_THIS
T&& getValue() && { assert(hasVal); return std::move(x); }
T&& operator*() && { assert(hasVal); return std::move(x); }
#endif

View File

@ -30,6 +30,18 @@
#define LLVM_USE_RVALUE_REFERENCES 0
#endif
/// \brief Does the compiler support r-value reference *this?
///
/// Sadly, this is separate from just r-value reference support because GCC
/// implemented everything but this thus far. No release of GCC yet has support
/// for this feature so it is enabled with Clang only.
/// FIXME: This should change to a version check when GCC grows support for it.
#if __has_feature(cxx_rvalue_references)
#define LLVM_HAS_RVALUE_REFERENCE_THIS 1
#else
#define LLVM_HAS_RVALUE_REFERENCE_THIS 0
#endif
/// llvm_move - Expands to ::std::move if the compiler supports
/// r-value references; otherwise, expands to the argument.
#if LLVM_USE_RVALUE_REFERENCES
@ -41,8 +53,8 @@
/// Expands to '&' if r-value references are supported.
///
/// This can be used to provide l-value/r-value overrides of member functions.
/// The r-value override should be guarded by LLVM_USE_RVALUE_REFERENCES
#if LLVM_USE_RVALUE_REFERENCES
/// The r-value override should be guarded by LLVM_HAS_RVALUE_REFERENCE_THIS
#if LLVM_HAS_RVALUE_REFERENCE_THIS
#define LLVM_LVALUE_FUNCTION &
#else
#define LLVM_LVALUE_FUNCTION