diff options
| -rw-r--r-- | libcxx/include/typeinfo | 106 |
1 files changed, 75 insertions, 31 deletions
diff --git a/libcxx/include/typeinfo b/libcxx/include/typeinfo index 451d9c950c3..5bcb6b2c1bb 100644 --- a/libcxx/include/typeinfo +++ b/libcxx/include/typeinfo @@ -79,48 +79,24 @@ public: namespace std // purposefully not using versioning namespace { +#if defined(_LIBCPP_ABI_MICROSOFT) + class _LIBCPP_EXCEPTION_ABI type_info { type_info& operator=(const type_info&); type_info(const type_info&); -#if defined(_LIBCPP_HAS_NONUNIQUE_TYPEINFO) - _LIBCPP_INLINE_VISIBILITY - int __compare_nonunique_names(const type_info &__arg) const _NOEXCEPT - { return __builtin_strcmp(name(), __arg.name()); } -#endif - -#if defined(_LIBCPP_ABI_MICROSOFT) mutable struct { const char *__undecorated_name; const char __decorated_name[1]; } __data; int __compare(const type_info &__rhs) const _NOEXCEPT; -#endif // _LIBCPP_ABI_MICROSOFT - -protected: -#if !defined(_LIBCPP_ABI_MICROSOFT) -#if defined(_LIBCPP_HAS_NONUNIQUE_TYPEINFO) - // A const char* with the non-unique RTTI bit possibly set. - uintptr_t __type_name; - - _LIBCPP_INLINE_VISIBILITY - explicit type_info(const char* __n) - : __type_name(reinterpret_cast<uintptr_t>(__n)) {} -#else - const char *__type_name; - - _LIBCPP_INLINE_VISIBILITY - explicit type_info(const char* __n) : __type_name(__n) {} -#endif -#endif // ! _LIBCPP_ABI_MICROSOFT public: _LIBCPP_AVAILABILITY_TYPEINFO_VTABLE virtual ~type_info(); -#if defined(_LIBCPP_ABI_MICROSOFT) const char *name() const _NOEXCEPT; _LIBCPP_INLINE_VISIBILITY @@ -134,8 +110,48 @@ public: bool operator==(const type_info& __arg) const _NOEXCEPT { return __compare(__arg) == 0; } -#else -#if defined(_LIBCPP_HAS_NONUNIQUE_TYPEINFO) + + _LIBCPP_INLINE_VISIBILITY + bool operator!=(const type_info& __arg) const _NOEXCEPT + { return !operator==(__arg); } +}; + +#elif defined(_LIBCPP_HAS_NONUNIQUE_TYPEINFO) + +// This implementation of type_info does not assume always a unique copy of +// the RTTI for a given type inside a program. It packs the pointer to the +// type name into a uintptr_t and reserves the high bit of that pointer (which +// is assumed to be free for use under the ABI in use) to represent whether +// that specific copy of the RTTI can be assumed unique inside the program. +// To implement equality-comparison of type_infos, we check whether BOTH +// type_infos are guaranteed unique, and if so, we simply compare the addresses +// of their type names instead of doing a deep string comparison, which is +// faster. If at least one of the type_infos can't guarantee uniqueness, we +// have no choice but to fall back to a deep string comparison. +// +// Note that the compiler is the one setting (or unsetting) the high bit of +// the pointer when it constructs the type_info, depending on whether it can +// guarantee uniqueness for that specific type_info. +class _LIBCPP_EXCEPTION_ABI type_info +{ + type_info& operator=(const type_info&); + type_info(const type_info&); + + _LIBCPP_INLINE_VISIBILITY + int __compare_nonunique_names(const type_info &__arg) const _NOEXCEPT + { return __builtin_strcmp(name(), __arg.name()); } + +protected: + uintptr_t __type_name; + + _LIBCPP_INLINE_VISIBILITY + explicit type_info(const char* __n) + : __type_name(reinterpret_cast<uintptr_t>(__n)) {} + +public: + _LIBCPP_AVAILABILITY_TYPEINFO_VTABLE + virtual ~type_info(); + _LIBCPP_INLINE_VISIBILITY const char* name() const _NOEXCEPT { @@ -174,7 +190,35 @@ public: return false; return __compare_nonunique_names(__arg) == 0; } -#else + + _LIBCPP_INLINE_VISIBILITY + bool operator!=(const type_info& __arg) const _NOEXCEPT + { return !operator==(__arg); } +}; + +#else // !_LIBCPP_ABI_MICROSOFT && !_LIBCPP_HAS_NONUNIQUE_TYPEINFO + +// This implementation of type_info assumes a unique copy of the RTTI for a +// given type inside a program. This is a valid assumption when abiding to +// Itanium ABI (http://itanium-cxx-abi.github.io/cxx-abi/abi.html#vtable-components). +// Under this assumption, we can always compare the addresses of the type names +// to implement equality-comparison of type_infos instead of having to perform +// a deep string comparison. +class _LIBCPP_EXCEPTION_ABI type_info +{ + type_info& operator=(const type_info&); + type_info(const type_info&); + +protected: + const char *__type_name; + + _LIBCPP_INLINE_VISIBILITY + explicit type_info(const char* __n) : __type_name(__n) {} + +public: + _LIBCPP_AVAILABILITY_TYPEINFO_VTABLE + virtual ~type_info(); + _LIBCPP_INLINE_VISIBILITY const char* name() const _NOEXCEPT { return __type_name; } @@ -190,14 +234,14 @@ public: _LIBCPP_INLINE_VISIBILITY bool operator==(const type_info& __arg) const _NOEXCEPT { return __type_name == __arg.__type_name; } -#endif -#endif // _LIBCPP_ABI_MICROSOFT _LIBCPP_INLINE_VISIBILITY bool operator!=(const type_info& __arg) const _NOEXCEPT { return !operator==(__arg); } }; +#endif + class _LIBCPP_EXCEPTION_ABI bad_cast : public exception { |
