Export VCRuntime entities properly (#4375)

stl/inc/exception

@@ -35,8 +35,11 @@ _STD_END
 
 _STD_BEGIN
 
-_EXPORT_STD class exception;
-_EXPORT_STD class bad_exception;
+#ifndef _VCRT_EXPORT_STD // TRANSITION, VCRuntime update expected in 17.10 Preview 3
+// Follow N4971 [module.interface]/6 by exporting aliases (a type alias is not an entity, N4971 [basic.pre]/3):
+_EXPORT_STD using exception     = exception;
+_EXPORT_STD using bad_exception = bad_exception;
+#endif // ^^^ workaround ^^^
 
 _EXPORT_STD using ::terminate;
 

stl/inc/new

@@ -17,70 +17,16 @@ _STL_DISABLE_CLANG_WARNINGS
 #pragma push_macro("new")
 #undef new
 
-#ifdef _BUILD_STD_MODULE
-#pragma warning(push)
-#pragma warning(disable : 28251) // Inconsistent annotation for 'new': this instance has no annotations.
-
-// Mirroring <vcruntime_new.h> declarations:
-
-_STD_BEGIN
-_EXPORT_STD extern "C++" struct nothrow_t;
-_EXPORT_STD extern "C++" const nothrow_t nothrow;
-_STD_END
-
-_EXPORT_STD extern "C++" _NODISCARD _VCRT_ALLOCATOR void* __CRTDECL operator new(size_t);
-_EXPORT_STD extern "C++" _NODISCARD _VCRT_ALLOCATOR void* __CRTDECL operator new(
-    size_t, const _STD nothrow_t&) noexcept;
-_EXPORT_STD extern "C++" _NODISCARD _VCRT_ALLOCATOR void* __CRTDECL operator new[](size_t);
-_EXPORT_STD extern "C++" _NODISCARD _VCRT_ALLOCATOR void* __CRTDECL operator new[](
-    size_t, const _STD nothrow_t&) noexcept;
-_EXPORT_STD extern "C++" void __CRTDECL operator delete(void*) noexcept;
-_EXPORT_STD extern "C++" void __CRTDECL operator delete(void*, size_t) noexcept;
-_EXPORT_STD extern "C++" void __CRTDECL operator delete(void*, const _STD nothrow_t&) noexcept;
-_EXPORT_STD extern "C++" void __CRTDECL operator delete[](void*) noexcept;
-_EXPORT_STD extern "C++" void __CRTDECL operator delete[](void*, size_t) noexcept;
-_EXPORT_STD extern "C++" void __CRTDECL operator delete[](void*, const _STD nothrow_t&) noexcept;
-
-#ifdef __cpp_aligned_new
-_STD_BEGIN
-#ifdef __EDG__ // TRANSITION, VSO-1618988
-extern "C++" {
-_EXPORT_STD enum class align_val_t : size_t;
-}
-#else // ^^^ workaround / no workaround vvv
-_EXPORT_STD extern "C++" enum class align_val_t : size_t;
-#endif // ^^^ no workaround ^^^
-_STD_END
-
-_EXPORT_STD extern "C++" _NODISCARD _VCRT_ALLOCATOR void* __CRTDECL operator new(size_t, _STD align_val_t);
-_EXPORT_STD extern "C++" _NODISCARD _VCRT_ALLOCATOR void* __CRTDECL operator new(
-    size_t, _STD align_val_t, const _STD nothrow_t&) noexcept;
-_EXPORT_STD extern "C++" _NODISCARD _VCRT_ALLOCATOR void* __CRTDECL operator new[](size_t, _STD align_val_t);
-_EXPORT_STD extern "C++" _NODISCARD _VCRT_ALLOCATOR void* __CRTDECL operator new[](
-    size_t, _STD align_val_t, const _STD nothrow_t&) noexcept;
-_EXPORT_STD extern "C++" void __CRTDECL operator delete(void*, _STD align_val_t) noexcept;
-_EXPORT_STD extern "C++" void __CRTDECL operator delete(void*, size_t, _STD align_val_t) noexcept;
-_EXPORT_STD extern "C++" void __CRTDECL operator delete(void*, _STD align_val_t, const _STD nothrow_t&) noexcept;
-_EXPORT_STD extern "C++" void __CRTDECL operator delete[](void*, _STD align_val_t) noexcept;
-_EXPORT_STD extern "C++" void __CRTDECL operator delete[](void*, size_t, _STD align_val_t) noexcept;
-_EXPORT_STD extern "C++" void __CRTDECL operator delete[](void*, _STD align_val_t, const _STD nothrow_t&) noexcept;
-#endif // defined(__cpp_aligned_new)
-
-_EXPORT_STD extern "C++" _NODISCARD void* __CRTDECL operator new(size_t, void*) noexcept;
-_EXPORT_STD extern "C++" _NODISCARD void* __CRTDECL operator new[](size_t, void*) noexcept;
-_EXPORT_STD extern "C++" void __CRTDECL operator delete(void*, void*) noexcept;
-_EXPORT_STD extern "C++" void __CRTDECL operator delete[](void*, void*) noexcept;
-
-#pragma warning(pop)
-#endif // defined(_BUILD_STD_MODULE)
-
 _STD_BEGIN
+#ifndef _VCRT_EXPORT_STD // TRANSITION, VCRuntime update expected in 17.10 Preview 3
 #if _HAS_EXCEPTIONS
-_EXPORT_STD class bad_alloc;
-_EXPORT_STD class bad_array_new_length;
+// Follow N4971 [module.interface]/6 by exporting aliases (a type alias is not an entity, N4971 [basic.pre]/3):
+_EXPORT_STD using bad_alloc            = bad_alloc;
+_EXPORT_STD using bad_array_new_length = bad_array_new_length;
 #else // ^^^ _HAS_EXCEPTIONS / !_HAS_EXCEPTIONS vvv
 // <exception> exports bad_alloc and bad_array_new_length.
 #endif // ^^^ !_HAS_EXCEPTIONS ^^^
+#endif // ^^^ workaround ^^^
 
 #if _HAS_CXX20
 _EXPORT_STD struct destroying_delete_t {

stl/inc/typeinfo

@@ -23,18 +23,26 @@ _STL_DISABLE_CLANG_WARNINGS
 #include <vcruntime_typeinfo.h>
 #pragma pop_macro("raw_name")
 
-_EXPORT_STD extern "C++" class type_info; // for typeid, MSVC looks for type_info in the global namespace
+#ifndef _VCRT_EXPORT_STD // TRANSITION, VCRuntime update expected in 17.10 Preview 3
+// Follow N4971 [module.interface]/6 by exporting aliases (a type alias is not an entity, N4971 [basic.pre]/3):
+_EXPORT_STD using type_info = type_info; // for typeid, MSVC looks for type_info in the global namespace
+#endif // ^^^ workaround ^^^
 
 _STD_BEGIN
 
 // size in pointers of std::function and std::any (roughly 3 pointers larger than std::string when building debug)
 _INLINE_VAR constexpr int _Small_object_num_ptrs = 6 + 16 / sizeof(void*);
 
+#ifndef _VCRT_EXPORT_STD // TRANSITION, VCRuntime update expected in 17.10 Preview 3
 _EXPORT_STD using ::type_info;
+#endif // ^^^ workaround ^^^
 
 #if _HAS_EXCEPTIONS
-_EXPORT_STD class bad_cast;
-_EXPORT_STD class bad_typeid;
+#ifndef _VCRT_EXPORT_STD // TRANSITION, VCRuntime update expected in 17.10 Preview 3
+// Follow N4971 [module.interface]/6 by exporting aliases (a type alias is not an entity, N4971 [basic.pre]/3):
+_EXPORT_STD using bad_cast   = bad_cast;
+_EXPORT_STD using bad_typeid = bad_typeid;
+#endif // ^^^ workaround ^^^
 #else // ^^^ _HAS_EXCEPTIONS / !_HAS_EXCEPTIONS vvv
 _EXPORT_STD class bad_cast : public exception { // base of all bad cast exceptions
 public:

stl/modules/std.ixx

@@ -36,6 +36,84 @@ export module std;
 #pragma warning(push)
 #pragma warning(disable : 5244) // '#include <meow>' in the purview of module 'std' appears erroneous.
 
+#include <yvals_core.h>
+#ifndef _VCRT_EXPORT_STD // TRANSITION, VCRuntime update expected in 17.10 Preview 3
+
+// N4971 [module.interface]/6: "A redeclaration of an entity X is implicitly exported
+// if X was introduced by an exported declaration; otherwise it shall not be exported."
+
+// Therefore, we'll need to introduce exported declarations of <vcruntime_new.h> machinery before including it.
+
+#pragma pack(push, _CRT_PACKING)
+#pragma warning(push, _STL_WARNING_LEVEL)
+#pragma warning(disable : _STL_DISABLED_WARNINGS)
+_STL_DISABLE_CLANG_WARNINGS
+#pragma push_macro("new")
+#undef new
+
+_STD_BEGIN
+export extern "C++" struct nothrow_t;
+
+export extern "C++" const nothrow_t nothrow;
+
+#ifdef __cpp_aligned_new
+export extern "C++" enum class align_val_t : size_t;
+#endif // ^^^ defined(__cpp_aligned_new) ^^^
+_STD_END
+
+export extern "C++" _NODISCARD _Ret_notnull_ _Post_writable_byte_size_(_Size)
+_VCRT_ALLOCATOR void* __CRTDECL operator new(size_t _Size);
+export extern "C++" _NODISCARD _Ret_maybenull_ _Success_(return != NULL)
+    _Post_writable_byte_size_(_Size) _VCRT_ALLOCATOR void* __CRTDECL
+    operator new(size_t _Size, const _STD nothrow_t&) noexcept;
+export extern "C++" _NODISCARD _Ret_notnull_ _Post_writable_byte_size_(_Size)
+_VCRT_ALLOCATOR void* __CRTDECL operator new[](size_t _Size);
+export extern "C++" _NODISCARD _Ret_maybenull_ _Success_(return != NULL)
+    _Post_writable_byte_size_(_Size) _VCRT_ALLOCATOR void* __CRTDECL
+    operator new[](size_t _Size, const _STD nothrow_t&) noexcept;
+export extern "C++" void __CRTDECL operator delete(void* _Block) noexcept;
+export extern "C++" void __CRTDECL operator delete(void* _Block, size_t _Size) noexcept;
+export extern "C++" void __CRTDECL operator delete(void* _Block, const _STD nothrow_t&) noexcept;
+export extern "C++" void __CRTDECL operator delete[](void* _Block) noexcept;
+export extern "C++" void __CRTDECL operator delete[](void* _Block, size_t _Size) noexcept;
+export extern "C++" void __CRTDECL operator delete[](void* _Block, const _STD nothrow_t&) noexcept;
+
+#ifdef __cpp_aligned_new
+export extern "C++" _NODISCARD _Ret_notnull_ _Post_writable_byte_size_(_Size)
+_VCRT_ALLOCATOR void* __CRTDECL operator new(size_t _Size, _STD align_val_t _Al);
+export extern "C++" _NODISCARD _Ret_maybenull_ _Success_(return != NULL)
+    _Post_writable_byte_size_(_Size) _VCRT_ALLOCATOR void* __CRTDECL
+    operator new(size_t _Size, _STD align_val_t _Al, const _STD nothrow_t&) noexcept;
+export extern "C++" _NODISCARD _Ret_notnull_ _Post_writable_byte_size_(_Size)
+_VCRT_ALLOCATOR void* __CRTDECL operator new[](size_t _Size, _STD align_val_t _Al);
+export extern "C++" _NODISCARD _Ret_maybenull_ _Success_(return != NULL)
+    _Post_writable_byte_size_(_Size) _VCRT_ALLOCATOR void* __CRTDECL
+    operator new[](size_t _Size, _STD align_val_t _Al, const _STD nothrow_t&) noexcept;
+export extern "C++" void __CRTDECL operator delete(void* _Block, _STD align_val_t _Al) noexcept;
+export extern "C++" void __CRTDECL operator delete(void* _Block, size_t _Size, _STD align_val_t _Al) noexcept;
+export extern "C++" void __CRTDECL operator delete(void* _Block, _STD align_val_t _Al, const _STD nothrow_t&) noexcept;
+export extern "C++" void __CRTDECL operator delete[](void* _Block, _STD align_val_t _Al) noexcept;
+export extern "C++" void __CRTDECL operator delete[](void* _Block, size_t _Size, _STD align_val_t _Al) noexcept;
+export extern "C++" void __CRTDECL operator delete[](
+    void* _Block, _STD align_val_t _Al, const _STD nothrow_t&) noexcept;
+#endif // ^^^ defined(__cpp_aligned_new) ^^^
+
+export extern "C++" _NODISCARD _MSVC_CONSTEXPR _Ret_notnull_ _Post_writable_byte_size_(_Size)
+    _Post_satisfies_(return == _Where) void* __CRTDECL
+    operator new(size_t _Size, _Writable_bytes_(_Size) void* _Where) noexcept;
+export extern "C++" _NODISCARD _Ret_notnull_ _Post_writable_byte_size_(_Size)
+    _Post_satisfies_(return == _Where) void* __CRTDECL
+    operator new[](size_t _Size, _Writable_bytes_(_Size) void* _Where) noexcept;
+export extern "C++" void __CRTDECL operator delete(void*, void*) noexcept;
+export extern "C++" void __CRTDECL operator delete[](void*, void*) noexcept;
+
+#pragma pop_macro("new")
+_STL_RESTORE_CLANG_WARNINGS
+#pragma warning(pop)
+#pragma pack(pop)
+
+#endif // ^^^ workaround ^^^
+
 // "C++ library headers" [tab:headers.cpp]
 #include <algorithm>
 #if _HAS_STATIC_RTTI

tests/std/include/test_header_units_and_modules.hpp

@@ -204,6 +204,10 @@ void test_deque() {
 void test_exception() {
     using namespace std;
     puts("Testing <exception>.");
+
+    static_assert(is_class_v<exception>);
+    static_assert(is_class_v<bad_exception>);
+
     assert(uncaught_exceptions() == 0);
     const exception_ptr ep = current_exception();
     assert(!ep);
@@ -471,6 +475,12 @@ void test_mutex() {
 void test_new() {
     using namespace std;
     puts("Testing <new>.");
+
+    static_assert(is_class_v<bad_alloc>);
+    static_assert(is_class_v<bad_array_new_length>);
+    static_assert(is_same_v<underlying_type_t<align_val_t>, size_t>);
+    static_assert(is_class_v<nothrow_t>);
+
     bool caught_bad_alloc = false;
 
     try {
@@ -988,6 +998,11 @@ void test_typeindex() {
 void test_typeinfo() {
     using namespace std;
     puts("Testing <typeinfo>.");
+
+    static_assert(is_class_v<type_info>);
+    static_assert(is_class_v<bad_cast>);
+    static_assert(is_class_v<bad_typeid>);
+
     const type_info& t1 = typeid(int);
     const type_info& t2 = typeid(const int&);
     const type_info& t3 = typeid(double);