diff options
Diffstat (limited to 'include/llvm/ADT/Optional.h')
-rw-r--r-- | include/llvm/ADT/Optional.h | 95 |
1 files changed, 31 insertions, 64 deletions
diff --git a/include/llvm/ADT/Optional.h b/include/llvm/ADT/Optional.h index 35ce0ce7010..25a3185064f 100644 --- a/include/llvm/ADT/Optional.h +++ b/include/llvm/ADT/Optional.h @@ -29,77 +29,36 @@ namespace llvm { class raw_ostream; namespace optional_detail { - /// Storage for any type. -// -template <class T> struct OptionalTrivialStorage { +template <typename T, bool = is_trivially_copyable<T>::value> struct OptionalStorage { AlignedCharArrayUnion<T> storage; bool hasVal = false; - OptionalTrivialStorage() = default; - OptionalTrivialStorage(OptionalTrivialStorage const &) = default; - OptionalTrivialStorage(OptionalTrivialStorage &&) = default; - OptionalTrivialStorage &operator=(OptionalTrivialStorage const &) = default; - OptionalTrivialStorage &operator=(OptionalTrivialStorage &&) = default; - ~OptionalTrivialStorage() = default; - - OptionalTrivialStorage(const T &y) : hasVal(true) { - new (storage.buffer) T(y); - } - OptionalTrivialStorage(T &&y) : hasVal(true) { - new (storage.buffer) T(std::move(y)); - } - - OptionalTrivialStorage &operator=(const T &y) { - new (storage.buffer) T(y); - hasVal = true; - return *this; - } - OptionalTrivialStorage &operator=(T &&y) { - new (storage.buffer) T(std::move(y)); - hasVal = true; - return *this; - } - - T *getPointer() { - assert(hasVal); - return reinterpret_cast<T *>(storage.buffer); - } - const T *getPointer() const { - assert(hasVal); - return reinterpret_cast<const T *>(storage.buffer); - } - void reset() { hasVal = false; } -}; - -template <typename T> struct OptionalStorage : OptionalTrivialStorage<T> { OptionalStorage() = default; - OptionalStorage(const T &y) : OptionalTrivialStorage<T>(y) {} - OptionalStorage(T &&y) : OptionalTrivialStorage<T>(std::move(y)) {} - - OptionalStorage(const OptionalStorage &O) : OptionalTrivialStorage<T>() { - this->hasVal = O.hasVal; - if (this->hasVal) - new (this->storage.buffer) T(*O.getPointer()); + OptionalStorage(const T &y) : hasVal(true) { new (storage.buffer) T(y); } + OptionalStorage(const OptionalStorage &O) : hasVal(O.hasVal) { + if (hasVal) + new (storage.buffer) T(*O.getPointer()); } - - OptionalStorage(OptionalStorage &&O) : OptionalTrivialStorage<T>() { - this->hasVal = O.hasVal; + OptionalStorage(T &&y) : hasVal(true) { + new (storage.buffer) T(std::forward<T>(y)); + } + OptionalStorage(OptionalStorage &&O) : hasVal(O.hasVal) { if (O.hasVal) { - new (this->storage.buffer) T(std::move(*O.getPointer())); + new (storage.buffer) T(std::move(*O.getPointer())); } } OptionalStorage &operator=(T &&y) { - if (this->hasVal) - *this->getPointer() = std::move(y); + if (hasVal) + *getPointer() = std::move(y); else { - OptionalTrivialStorage<T>::operator=(std::move(y)); + new (storage.buffer) T(std::move(y)); + hasVal = true; } return *this; } - OptionalStorage &operator=(OptionalStorage &&O) { if (!O.hasVal) reset(); @@ -115,10 +74,11 @@ template <typename T> struct OptionalStorage : OptionalTrivialStorage<T> { // requirements (notably: the existence of a default ctor) when implemented // in that way. Careful SFINAE to avoid such pitfalls would be required. OptionalStorage &operator=(const T &y) { - if (this->hasVal) - *this->getPointer() = y; + if (hasVal) + *getPointer() = y; else { - OptionalTrivialStorage<T>::operator=(y); + new (storage.buffer) T(y); + hasVal = true; } return *this; } @@ -133,19 +93,26 @@ template <typename T> struct OptionalStorage : OptionalTrivialStorage<T> { ~OptionalStorage() { reset(); } void reset() { - if (this->hasVal) { - (*this->getPointer()).~T(); - OptionalTrivialStorage<T>::reset(); + if (hasVal) { + (*getPointer()).~T(); + hasVal = false; } } + + T *getPointer() { + assert(hasVal); + return reinterpret_cast<T *>(storage.buffer); + } + const T *getPointer() const { + assert(hasVal); + return reinterpret_cast<const T *>(storage.buffer); + } }; } // namespace optional_detail template <typename T> class Optional { - typename std::conditional<is_trivially_copyable<T>::value, - optional_detail::OptionalTrivialStorage<T>, - optional_detail::OptionalStorage<T>>::type Storage; + optional_detail::OptionalStorage<T> Storage; public: using value_type = T; |