[libcxx] type_info support for MSVC

[K-ballo]

Summary

Adds type_info support for MSVC. Note that it is expected in the global namespace.

I have implemented some of the member functions in exception.cpp because they have a dependency on string or cstring. Suggestions on how to implement them inline are welcomed (note no __builtin_strcmp in MSVC).

[majnemer]

include/typeinfo

164–165

This name isn't demangled. We can't call UnDecorateSymbolName, it's only available if dbghelp.dll is present.

Perhaps libc++abi should have a demangler?

[K-ballo]

include/typeinfo

164–165

Should it be demangled? It is a lot of trouble for little benefit, given that the implementation is conformant as is.

[K-ballo]

Waiting for VS2015RTM

include/typeinfo

 #include <exception>
 #include <cstddef>
 #include <cstdint>
 
 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
 #pragma GCC system_header
 #endif
 
+#ifndef _LIBCPP_MSVC
+
 namespace std  // purposefully not using versioning namespace
 {
 
 class _LIBCPP_EXCEPTION_ABI type_info
 {
     type_info& operator=(const type_info&);
     type_info(const type_info&);
 protected:

 #ifdef _LIBCPP_NONUNIQUE_RTTI_BIT
   private:
     _LIBCPP_INLINE_VISIBILITY
     int __compare_nonunique_names(const type_info &__arg) const _NOEXCEPT
         {return __builtin_strcmp(name(), __arg.name());}
 #endif
 };
 
+#else
+
+class _LIBCPP_EXCEPTION_ABI type_info
+{
+    type_info& operator=(const type_info&);
+    type_info(const type_info&);
+protected:
+    void *__unused;
+    char __type_name[1];
+
+public:
+    virtual ~type_info();
+    
+    _LIBCPP_INLINE_VISIBILITY
+    const char* name() const _NOEXCEPT
+        {return __type_name;}
+
+    bool before(const type_info& __arg) const _NOEXCEPT;
+
+    size_t hash_code() const _NOEXCEPT;
+
+    bool operator==(const type_info& __arg) const _NOEXCEPT;
+    _LIBCPP_INLINE_VISIBILITY
+    bool operator!=(const type_info& __arg) const _NOEXCEPT
+        {return !operator==(__arg);}
+};
+
+namespace std  // purposefully not using versioning namespace
+{
+    using ::type_info;
+
+#endif  // !_LIBCPP_MSVC
+
 class _LIBCPP_EXCEPTION_ABI bad_cast
     : public exception
 {
 public:
     bad_cast() _NOEXCEPT;
     virtual ~bad_cast() _NOEXCEPT;
     virtual const char* what() const _NOEXCEPT;
 };

src/typeinfo.cpp

 #ifdef __APPLE__
 #include <cxxabi.h>
 #elif defined(LIBCXXRT) || __has_include(<cxxabi.h>)
 #include <cxxabi.h>
 #endif
 
 #include "typeinfo"
 
+#ifdef _LIBCPP_MSVC
+
+#include <string> // for __do_string_hash
+#include <cstring>
+
+bool type_info::before(const type_info& __arg) const _NOEXCEPT
+{
+    return strcmp(__type_name, __arg.__type_name) < 0;
+}
+
+size_t type_info::hash_code() const _NOEXCEPT
+{
+    return std::__do_string_hash(__type_name, __type_name + strlen(__type_name));
+}
+
+bool type_info::operator==(const type_info& __arg) const _NOEXCEPT
+{
+    return __type_name == __arg.__type_name ||
+           strcmp(__type_name, __arg.__type_name) == 0;
+}
+
+type_info::~type_info() _NOEXCEPT
+{
+}
+
+#endif  // _LIBCPP_MSVC
+
 #if !defined(LIBCXXRT) && !defined(_LIBCPPABI_VERSION)
 
 std::bad_cast::bad_cast() _NOEXCEPT
 {
 }
 
 std::bad_typeid::bad_typeid() _NOEXCEPT
 {