[libc++] Support Microsoft ABI without vcruntime headers

The vcruntime headers are hairy and clash with both libc++ headers
themselves and other libraries. libc++ normally deals with the clashes
by deferring to the vcruntime headers and silencing its own definitions,
but for clients which don't want to depend on vcruntime headers, it's
desirable to support the opposite, i.e. have libc++ provide its own
definitions.

Certain operator new/delete replacement scenarios are not currently
supported in this mode, which requires some tests to be marked XFAIL.
The added documentation has more details.

Differential Revision: https://reviews.llvm.org/D38522

git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@315234 91177308-0d34-0410-b5e6-96231b3b80d8

3 files changed, 101 insertions, 19 deletions

diff --git a/src/new.cpp b/src/new.cpp
index 01df25121..e228a0d83 100644
--- a/src/new.cpp
+++ b/src/new.cpp
@@ -15,7 +15,9 @@
 #include "include/atomic_support.h"
 
 #if defined(_LIBCPP_ABI_MICROSOFT)
-// nothing todo
+#if defined(_LIBCPP_NO_VCRUNTIME)
+#include "support/runtime/new_handler_fallback.ipp"
+#endif
 #elif defined(LIBCXX_BUILDING_LIBCXXABI)
 #include <cxxabi.h>
 #elif defined(LIBCXXRT)
@@ -54,7 +56,8 @@ __throw_bad_alloc()
 
 }  // std
 
-#if !defined(__GLIBCXX__) && !defined(_LIBCPP_ABI_MICROSOFT) && \
+#if !defined(__GLIBCXX__) &&                                                   \
+    (!defined(_LIBCPP_ABI_MICROSOFT) || defined(_LIBCPP_NO_VCRUNTIME)) &&      \
     !defined(_LIBCPP_DISABLE_NEW_DELETE_DEFINITIONS)
 
 // Implement all new and delete operators as weak definitions
@@ -300,4 +303,4 @@ operator delete[] (void* ptr, size_t, std::align_val_t alignment) _NOEXCEPT
 }
 
 #endif // !_LIBCPP_HAS_NO_ALIGNED_ALLOCATION
-#endif // !__GLIBCXX__ && !_LIBCPP_ABI_MICROSOFT && !_LIBCPP_DISABLE_NEW_DELETE_DEFINITIONS
+#endif // !__GLIBCXX__ && (!_LIBCPP_ABI_MICROSOFT || _LIBCPP_NO_VCRUNTIME) && !_LIBCPP_DISABLE_NEW_DELETE_DEFINITIONS
diff --git a/src/support/runtime/exception_msvc.ipp b/src/support/runtime/exception_msvc.ipp
index 443961ebf..d5bf5b726 100644
--- a/src/support/runtime/exception_msvc.ipp
+++ b/src/support/runtime/exception_msvc.ipp
@@ -14,12 +14,35 @@
 
 #include <stdio.h>
 #include <stdlib.h>
-#include <eh.h>
-#include <corecrt_terminate.h>
+
+#if !defined(_ACRTIMP)
+#define _ACRTIMP __declspec(dllimport)
+#endif
+
+#if !defined(_VCRTIMP)
+#define _VCRTIMP __declspec(dllimport)
+#endif
+
+#if !defined(__CRTDECL)
+#define __CRTDECL __cdecl
+#endif
+
+extern "C" {
+typedef void (__CRTDECL* terminate_handler)();
+_ACRTIMP terminate_handler __cdecl set_terminate(
+    terminate_handler _NewTerminateHandler) throw();
+_ACRTIMP terminate_handler __cdecl _get_terminate();
+
+typedef void (__CRTDECL* unexpected_handler)();
+_VCRTIMP unexpected_handler __cdecl set_unexpected(
+    unexpected_handler _NewUnexpectedHandler) throw();
+_VCRTIMP unexpected_handler __cdecl _get_unexpected();
+
+_VCRTIMP int __cdecl __uncaught_exceptions();
+}
 
 namespace std {
 
-// libcxxrt provides implementations of these functions itself.
 unexpected_handler
 set_unexpected(unexpected_handler func) _NOEXCEPT {
   return ::set_unexpected(func);
@@ -114,4 +137,54 @@ bad_typeid::what() const _NOEXCEPT
   return "std::bad_typeid";
 }
 
+#if defined(_LIBCPP_NO_VCRUNTIME)
+exception::~exception() _NOEXCEPT
+{
+}
+
+const char* exception::what() const _NOEXCEPT
+{
+  return "std::exception";
+}
+
+
+bad_exception::~bad_exception() _NOEXCEPT
+{
+}
+
+const char* bad_exception::what() const _NOEXCEPT
+{
+  return "std::bad_exception";
+}
+
+
+bad_alloc::bad_alloc() _NOEXCEPT
+{
+}
+
+bad_alloc::~bad_alloc() _NOEXCEPT
+{
+}
+
+const char*
+bad_alloc::what() const _NOEXCEPT
+{
+    return "std::bad_alloc";
+}
+
+bad_array_new_length::bad_array_new_length() _NOEXCEPT
+{
+}
+
+bad_array_new_length::~bad_array_new_length() _NOEXCEPT
+{
+}
+
+const char*
+bad_array_new_length::what() const _NOEXCEPT
+{
+    return "bad_array_new_length";
+}
+#endif // _LIBCPP_NO_VCRUNTIME
+
 } // namespace std
diff --git a/src/support/runtime/exception_pointer_msvc.ipp b/src/support/runtime/exception_pointer_msvc.ipp
index eab5d30a9..5ca7519a6 100644
--- a/src/support/runtime/exception_pointer_msvc.ipp
+++ b/src/support/runtime/exception_pointer_msvc.ipp
@@ -10,26 +10,32 @@
 
 #include <stdio.h>
 #include <stdlib.h>
-#include <yvals.h> // for _CRTIMP2_PURE
 
-_CRTIMP2_PURE void __CLRCALL_PURE_OR_CDECL __ExceptionPtrCreate(_Out_ void*);
-_CRTIMP2_PURE void __CLRCALL_PURE_OR_CDECL __ExceptionPtrDestroy(_Inout_ void*);
-_CRTIMP2_PURE void __CLRCALL_PURE_OR_CDECL __ExceptionPtrCopy(_Out_ void*,
-                                                              _In_ const void*);
+#if !defined(_CRTIMP2_PURE)
+#define _CRTIMP2_PURE __declspec(dllimport)
+#endif
+
+#if !defined(__CLRCALL_PURE_OR_CDECL)
+#define __CLRCALL_PURE_OR_CDECL __cdecl
+#endif
+
+_CRTIMP2_PURE void __CLRCALL_PURE_OR_CDECL __ExceptionPtrCreate(void*);
+_CRTIMP2_PURE void __CLRCALL_PURE_OR_CDECL __ExceptionPtrDestroy(void*);
+_CRTIMP2_PURE void __CLRCALL_PURE_OR_CDECL __ExceptionPtrCopy(void*,
+                                                              const void*);
 _CRTIMP2_PURE void __CLRCALL_PURE_OR_CDECL
-__ExceptionPtrAssign(_Inout_ void*, _In_ const void*);
+__ExceptionPtrAssign(void*, const void*);
 _CRTIMP2_PURE bool __CLRCALL_PURE_OR_CDECL
-__ExceptionPtrCompare(_In_ const void*, _In_ const void*);
+__ExceptionPtrCompare(const void*, const void*);
 _CRTIMP2_PURE bool __CLRCALL_PURE_OR_CDECL
-__ExceptionPtrToBool(_In_ const void*);
-_CRTIMP2_PURE void __CLRCALL_PURE_OR_CDECL __ExceptionPtrSwap(_Inout_ void*,
-                                                              _Inout_ void*);
+__ExceptionPtrToBool(const void*);
+_CRTIMP2_PURE void __CLRCALL_PURE_OR_CDECL __ExceptionPtrSwap(void*, void*);
 _CRTIMP2_PURE void __CLRCALL_PURE_OR_CDECL
-__ExceptionPtrCurrentException(_Out_ void*);
+__ExceptionPtrCurrentException(void*);
 [[noreturn]] _CRTIMP2_PURE void __CLRCALL_PURE_OR_CDECL
-__ExceptionPtrRethrow(_In_ const void*);
+__ExceptionPtrRethrow(const void*);
 _CRTIMP2_PURE void __CLRCALL_PURE_OR_CDECL
-__ExceptionPtrCopyException(_Inout_ void*, _In_ const void*, _In_ const void*);
+__ExceptionPtrCopyException(void*, const void*, const void*);
 
 namespace std {