[libcxx] [test] Conditionally workaround C1XX/EDG bugs

[CaseyCarter]

Summary

Test support machinery changes needed to parse with EDG and compile with C1XX's /Za flag that disables MS extensions.

I try to make changes to <optional> and the optional/variant tests simultaneously in the MS STL and in libc++, which realistically requires that I keep the tests largely synchronized between libc++ and our internal test suite. As a first step toward automating that integration, I'd like to upstream this patch.

This change works around a couple of bugs:

1. EDG doesn't like explicit constexpr in a derived class. This program:

struct Base {};

struct Derived : Base {
    constexpr Derived() = default;
};

triggers "error: defaulted default constructor cannot be constexpr."

2. C1XX with /Za has no idea which constructor needs to be valid for copy elision.

The change also conditionally disables parts of the msvc_stdlib_force_include.hpp header that conflict with external configuration when _LIBCXX_IN_DEVCRT is defined.

[STL_MSFT]

test/support/archetypes.hpp

20 ↗

(On Diff #97530)

I think that this comment doesn't match the ifndef check, but it's a style question.

test/support/archetypes.ipp

10 ↗

(On Diff #97530)

Should you define it to be inline instead of nothing?

[CaseyCarter]

test/support/archetypes.hpp

20 ↗

(On Diff #97530)

I know which style *I* prefer, because I wrote it, and I know which style *you* prefer, because you commented. I'll change this when Marshall or Eric let me know what they prefer here.

test/support/archetypes.ipp

10 ↗

(On Diff #97530)

This macro is typically defined to either constexpr or nothing - see the definitions in archetypes.hpp above.

libcxx/trunk/test/support/archetypes.hpp

 #ifndef TEST_SUPPORT_ARCHETYPES_HPP
 #define TEST_SUPPORT_ARCHETYPES_HPP
 
 #include <type_traits>
 #include <cassert>
 
 #include "test_macros.h"
+#include "test_workarounds.h"
 
 #if TEST_STD_VER >= 11
 
 namespace ArchetypeBases {
 
 template <bool, class T>
 struct DepType : T {};
 
 struct NullBase {
+#ifndef TEST_WORKAROUND_C1XX_BROKEN_ZA_CTOR_CHECK
 protected:
+#endif // !TEST_WORKAROUND_C1XX_BROKEN_ZA_CTOR_CHECK
   NullBase() = default;
   NullBase(NullBase const&) = default;
   NullBase& operator=(NullBase const&) = default;
   NullBase(NullBase &&) = default;
   NullBase& operator=(NullBase &&) = default;
 };
 
 template <class Derived, bool Explicit = false>
struct TestBase {
     explicit TestBase(std::initializer_list<int>& il, int = 0) noexcept : value(static_cast<int>(il.size())) {
         ++alive; ++constructed; ++value_constructed;
     }
     TestBase& operator=(int xvalue) noexcept {
       value = xvalue;
       ++assigned; ++value_assigned;
       return *this;
     }
+#ifndef TEST_WORKAROUND_C1XX_BROKEN_ZA_CTOR_CHECK
 protected:
+#endif // !TEST_WORKAROUND_C1XX_BROKEN_ZA_CTOR_CHECK
     ~TestBase() {
       assert(value != -999); assert(alive > 0);
       --alive; ++destroyed; value = -999;
     }
     explicit TestBase(TestBase const& o) noexcept : value(o.value) {
         assert(o.value != -1); assert(o.value != -999);
         ++alive; ++constructed; ++copy_constructed;
     }
struct ValueBase {
     template <bool Dummy = true, typename std::enable_if<Dummy && !Explicit, bool>::type = true>
     constexpr ValueBase(std::initializer_list<int>& il, int = 0) : value(static_cast<int>(il.size())) {}
     TEST_CONSTEXPR_CXX14 ValueBase& operator=(int xvalue) noexcept {
         value = xvalue;
         return *this;
     }
     //~ValueBase() { assert(value != -999); value = -999; }
     int value;
+#ifndef TEST_WORKAROUND_C1XX_BROKEN_ZA_CTOR_CHECK
 protected:
+#endif // !TEST_WORKAROUND_C1XX_BROKEN_ZA_CTOR_CHECK
     constexpr static int check_value(int const& val) {
 #if TEST_STD_VER < 14
       return val == -1 || val == 999 ? (TEST_THROW(42), 0) : val;
 #else
       assert(val != -1); assert(val != 999);
       return val;
 #endif
     }
struct TrivialValueBase {
     explicit constexpr TrivialValueBase(int, int y) : value(y) {}
     template <bool Dummy = true, typename std::enable_if<Dummy && !Explicit, bool>::type = true>
     constexpr TrivialValueBase(int, int y) : value(y) {}
     template <bool Dummy = true, typename std::enable_if<Dummy && Explicit, bool>::type = true>
     explicit constexpr TrivialValueBase(std::initializer_list<int>& il, int = 0) : value(static_cast<int>(il.size())) {}
     template <bool Dummy = true, typename std::enable_if<Dummy && !Explicit, bool>::type = true>
     constexpr TrivialValueBase(std::initializer_list<int>& il, int = 0) : value(static_cast<int>(il.size())) {}
     int value;
+#ifndef TEST_WORKAROUND_C1XX_BROKEN_ZA_CTOR_CHECK
 protected:
+#endif // !TEST_WORKAROUND_C1XX_BROKEN_ZA_CTOR_CHECK
     constexpr TrivialValueBase() noexcept : value(0) {}
 };
 
 }
 
 //============================================================================//
 // Trivial Implicit Test Types
 namespace ImplicitTypes {

libcxx/trunk/test/support/archetypes.ipp

 
 #ifndef DEFINE_BASE
 #define DEFINE_BASE(Name) ::ArchetypeBases::NullBase
 #endif
 #ifndef DEFINE_EXPLICIT
 #define DEFINE_EXPLICIT
 #endif
 #ifndef DEFINE_CONSTEXPR
+#ifdef TEST_WORKAROUND_EDG_EXPLICIT_CONSTEXPR
+#define DEFINE_CONSTEXPR
+#else // TEST_WORKAROUND_EDG_EXPLICIT_CONSTEXPR
 #define DEFINE_CONSTEXPR constexpr
+#endif // TEST_WORKAROUND_EDG_EXPLICIT_CONSTEXPR
 #endif
 #ifndef DEFINE_ASSIGN_CONSTEXPR
 #if TEST_STD_VER >= 14
 #define DEFINE_ASSIGN_CONSTEXPR DEFINE_CONSTEXPR
 #else
 #define DEFINE_ASSIGN_CONSTEXPR
 #endif
 #endif

libcxx/trunk/test/support/msvc_stdlib_force_include.hpp

 //===----------------------------------------------------------------------===//
 //
 //                     The LLVM Compiler Infrastructure
 //
 // This file is dual licensed under the MIT and the University of Illinois Open
 // Source Licenses. See LICENSE.TXT for details.
 //
 //===----------------------------------------------------------------------===//
 
 #ifndef SUPPORT_MSVC_STDLIB_FORCE_INCLUDE_HPP
 #define SUPPORT_MSVC_STDLIB_FORCE_INCLUDE_HPP
 
 // This header is force-included when running the libc++ tests against the
 // MSVC standard library.
 
+#ifndef _LIBCXX_IN_DEVCRT
     // Silence warnings about CRT machinery.
     #define _CRT_SECURE_NO_WARNINGS
 
     // Avoid assertion dialogs.
     #define _CRT_SECURE_INVALID_PARAMETER(EXPR) ::abort()
+#endif // _LIBCXX_IN_DEVCRT
 
 #include <crtdbg.h>
 #include <stdlib.h>
 
 #if defined(_LIBCPP_VERSION)
     #error This header may not be used when targeting libc++
 #endif
 
 // Indicates that we are using the MSVC standard library.
 #ifndef _MSVC_STL_VER
     #define _MSVC_STL_VER 42
 #endif
 
+#ifndef _LIBCXX_IN_DEVCRT
 struct AssertionDialogAvoider {
     AssertionDialogAvoider() {
         _CrtSetReportMode(_CRT_ASSERT, _CRTDBG_MODE_FILE);
         _CrtSetReportFile(_CRT_ASSERT, _CRTDBG_FILE_STDERR);
 
         _CrtSetReportMode(_CRT_ERROR, _CRTDBG_MODE_FILE);
         _CrtSetReportFile(_CRT_ERROR, _CRTDBG_FILE_STDERR);
     }
 };
 
 const AssertionDialogAvoider assertion_dialog_avoider{};
+#endif // _LIBCXX_IN_DEVCRT
 
 // MSVC frontend only configurations
 #if !defined(__clang__)
     // Simulate feature-test macros.
     #define __has_feature(X) _MSVC_HAS_FEATURE_ ## X
     #define _MSVC_HAS_FEATURE_cxx_exceptions    1
     #define _MSVC_HAS_FEATURE_cxx_rtti          1
     #define _MSVC_HAS_FEATURE_address_sanitizer 0

 // atomic_is_lock_free.pass.cpp needs this VS 2015 Update 2 fix.
 #define _ENABLE_ATOMIC_ALIGNMENT_FIX
 
 // Enable features that /std:c++latest removes by default.
 #define _HAS_AUTO_PTR_ETC          1
 #define _HAS_FUNCTION_ASSIGN       1
 #define _HAS_OLD_IOSTREAMS_MEMBERS 1
 
     // Silence warnings about raw pointers and other unchecked iterators.
     #define _SCL_SECURE_NO_WARNINGS
+#endif // _LIBCXX_IN_DEVCRT
 
 #include <ciso646>
 
 #if _HAS_CXX17
     #define TEST_STD_VER 17
 #else // _HAS_CXX17
     #define TEST_STD_VER 14
 #endif // _HAS_CXX17
 
 #endif // SUPPORT_MSVC_STDLIB_FORCE_INCLUDE_HPP

libcxx/trunk/test/support/test.workarounds/c1xx_broken_za_ctor_check.pass.cpp

+//===----------------------------------------------------------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is dual licensed under the MIT and the University of Illinois Open
+// Source Licenses. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+// UNSUPPORTED: c++98, c++03
+
+// Verify TEST_WORKAROUND_C1XX_BROKEN_ZA_CTOR_CHECK.
+
+#include <type_traits>
+
+#include "test_workarounds.h"
+
+struct X {
+    X(int) {}
+
+    X(X&&) = default;
+    X& operator=(X&&) = default;
+
+private:
+    X(const X&) = default;
+    X& operator=(const X&) = default;
+};
+
+void PushFront(X&&) {}
+
+template<class T = int>
+auto test(int) -> decltype(PushFront(std::declval<T>()), std::true_type{});
+auto test(long) -> std::false_type;
+
+int main() {
+#if defined(TEST_WORKAROUND_C1XX_BROKEN_ZA_CTOR_CHECK)
+    static_assert(!decltype(test(0))::value, "");
+#else
+    static_assert(decltype(test(0))::value, "");
+#endif
+}

libcxx/trunk/test/support/test_macros.h

 #ifdef __is_identifier
 // '__is_identifier' returns '0' if '__x' is a reserved identifier provided by
 // the compiler and '1' otherwise.
 #define TEST_HAS_BUILTIN_IDENTIFIER(X) !__is_identifier(X)
 #else
 #define TEST_HAS_BUILTIN_IDENTIFIER(X) 0
 #endif
 
-#if defined(__clang__)
-#define TEST_COMPILER_CLANG
+#if defined(__EDG__)
+# define TEST_COMPILER_EDG
+#elif defined(__clang__)
+# define TEST_COMPILER_CLANG
 # if defined(__apple_build_version__)
-#   define TEST_COMPILER_APPLE_CLANG
+#  define TEST_COMPILER_APPLE_CLANG
 # endif
 #elif defined(_MSC_VER)
 # define TEST_COMPILER_C1XX
 #elif defined(__GNUC__)
 # define TEST_COMPILER_GCC
 #endif
 
 #if defined(__apple_build_version__)

libcxx/trunk/test/support/test_workarounds.h

 // -*- C++ -*-
 //===----------------------------------------------------------------------===//
 //
 //                     The LLVM Compiler Infrastructure
 //
 // This file is dual licensed under the MIT and the University of Illinois Open
 // Source Licenses. See LICENSE.TXT for details.
 //
 //===----------------------------------------------------------------------===//
 
 #ifndef SUPPORT_TEST_WORKAROUNDS_H
 #define SUPPORT_TEST_WORKAROUNDS_H
 
 #include "test_macros.h"
 
+#if defined(TEST_COMPILER_EDG)
+# define TEST_WORKAROUND_EDG_EXPLICIT_CONSTEXPR
+#endif
+
 #if defined(TEST_COMPILER_C1XX)
 # define TEST_WORKAROUND_C1XX_BROKEN_NULLPTR_CONVERSION_OPERATOR
 # define TEST_WORKAROUND_C1XX_BROKEN_IS_TRIVIALLY_COPYABLE
+# ifndef _MSC_EXTENSIONS
+#  define TEST_WORKAROUND_C1XX_BROKEN_ZA_CTOR_CHECK
+# endif
 #endif
 
 #endif // SUPPORT_TEST_WORKAROUNDS_H