[libc++][test] Enhance ADDITIONAL_COMPILE_FLAGS, use TEST_MEOW_DIAGNOSTIC_IGNORED sparingly (#75317)

This is the last PR that's needed (for now) to get libc++'s tests
working with MSVC's STL.

The ADDITIONAL_COMPILE_FLAGS machinery is very useful, but also very
problematic for MSVC, as it doesn't understand most of Clang's compiler
options. We've been dealing with this by simply marking anything that
uses ADDITIONAL_COMPILE_FLAGS as FAIL or SKIPPED, but that creates
significant gaps in test coverage.

Fortunately, ADDITIONAL_COMPILE_FLAGS also supports "features", which
can be slightly enhanced to send Clang-compatible and MSVC-compatible
options to the right compilers.

This patch adds the gcc-style-warnings and cl-style-warnings Lit features,
and uses that to pass the appropriate warning flags to tests. It also uses
TEST_MEOW_DIAGNOSTIC_IGNORED for a few local suppressions of MSVC
warnings.

Author: StephanTLavavej

libcxx/test/std/algorithms/alg.modifying.operations/alg.replace/ranges.replace.pass.cpp

@@ -6,6 +6,9 @@
 //
 //===----------------------------------------------------------------------===//
 
+// MSVC warning C4244: 'argument': conversion from 'const _Ty2' to 'T', possible loss of data
+// ADDITIONAL_COMPILE_FLAGS(cl-style-warnings): /wd4244
+
 // <algorithm>
 
 // UNSUPPORTED: c++03, c++11, c++14, c++17

libcxx/test/std/algorithms/alg.nonmodifying/alg.equal/equal.pass.cpp

@@ -19,7 +19,11 @@
 //   equal(Iter1 first1, Iter1 last1, Iter2 first2, Iter2 last2);
 
 // We test the cartesian product, so we sometimes compare differently signed types
-// ADDITIONAL_COMPILE_FLAGS: -Wno-sign-compare
+// ADDITIONAL_COMPILE_FLAGS(gcc-style-warnings): -Wno-sign-compare
+// MSVC warning C4242: 'argument': conversion from 'int' to 'const _Ty', possible loss of data
+// MSVC warning C4244: 'argument': conversion from 'wchar_t' to 'const _Ty', possible loss of data
+// MSVC warning C4389: '==': signed/unsigned mismatch
+// ADDITIONAL_COMPILE_FLAGS(cl-style-warnings): /wd4242 /wd4244 /wd4389
 
 #include <algorithm>
 #include <cassert>
@@ -58,6 +62,10 @@ struct Test {
 struct TestNarrowingEqualTo {
   template <class UnderlyingType>
   TEST_CONSTEXPR_CXX20 void operator()() {
+    TEST_DIAGNOSTIC_PUSH
+    // MSVC warning C4310: cast truncates constant value
+    TEST_MSVC_DIAGNOSTIC_IGNORED(4310)
+
     UnderlyingType a[] = {
         UnderlyingType(0x1000),
         UnderlyingType(0x1001),
@@ -71,6 +79,8 @@ struct TestNarrowingEqualTo {
         UnderlyingType(0x1603),
         UnderlyingType(0x1604)};
 
+    TEST_DIAGNOSTIC_POP
+
     assert(std::equal(a, a + 5, b, std::equal_to<char>()));
 #if TEST_STD_VER >= 14
     assert(std::equal(a, a + 5, b, b + 5, std::equal_to<char>()));

libcxx/test/std/algorithms/alg.nonmodifying/alg.find/find.pass.cpp

@@ -6,7 +6,9 @@
 //
 //===----------------------------------------------------------------------===//
 
-// ADDITIONAL_COMPILE_FLAGS: -Wno-sign-compare
+// ADDITIONAL_COMPILE_FLAGS(gcc-style-warnings): -Wno-sign-compare
+// MSVC warning C4389: '==': signed/unsigned mismatch
+// ADDITIONAL_COMPILE_FLAGS(cl-style-warnings): /wd4389
 
 // <algorithm>
 

libcxx/test/std/algorithms/alg.nonmodifying/alg.find/ranges.find.pass.cpp

@@ -10,7 +10,10 @@
 
 // UNSUPPORTED: c++03, c++11, c++14, c++17
 
-// ADDITIONAL_COMPILE_FLAGS: -Wno-sign-compare
+// ADDITIONAL_COMPILE_FLAGS(gcc-style-warnings): -Wno-sign-compare
+// MSVC warning C4242: 'argument': conversion from 'const _Ty' to 'ElementT', possible loss of data
+// MSVC warning C4244: 'argument': conversion from 'const _Ty' to 'ElementT', possible loss of data
+// ADDITIONAL_COMPILE_FLAGS(cl-style-warnings): /wd4242 /wd4244
 
 // template<input_iterator I, sentinel_for<I> S, class T, class Proj = identity>
 //   requires indirect_binary_predicate<ranges::equal_to, projected<I, Proj>, const T*>

libcxx/test/std/atomics/atomics.types.generic/general.compile.pass.cpp

@@ -74,9 +74,15 @@ void test() {
 
   TEST_IGNORE_NODISCARD a.is_lock_free();
 
+  TEST_DIAGNOSTIC_PUSH
+  // MSVC warning C4197: 'volatile std::atomic<operator_hijacker>': top-level volatile in cast is ignored
+  TEST_MSVC_DIAGNOSTIC_IGNORED(4197)
+
   TEST_IGNORE_NODISCARD T();
   TEST_IGNORE_NODISCARD T(v);
 
+  TEST_DIAGNOSTIC_POP
+
   TEST_IGNORE_NODISCARD a.load();
   TEST_IGNORE_NODISCARD static_cast<typename T::value_type>(a);
   a.store(v);

libcxx/test/std/atomics/atomics.types.generic/pointer.compile.pass.cpp

@@ -98,8 +98,16 @@ void test() {
 
   a.store(v);
   a = v;
+
+  TEST_DIAGNOSTIC_PUSH
+  // MSVC warning C4197: 'volatile std::atomic<operator_hijacker *>': top-level volatile in cast is ignored
+  TEST_MSVC_DIAGNOSTIC_IGNORED(4197)
+
   TEST_IGNORE_NODISCARD T();
   TEST_IGNORE_NODISCARD T(v);
+
+  TEST_DIAGNOSTIC_POP
+
   TEST_IGNORE_NODISCARD a.load();
   TEST_IGNORE_NODISCARD static_cast<typename T::value_type>(a);
   TEST_IGNORE_NODISCARD* a;

libcxx/test/std/concepts/concepts.lang/concept.default.init/default_initializable.compile.pass.cpp

@@ -10,7 +10,7 @@
 
 // We voluntarily use std::default_initializable on types that have redundant
 // or ignored cv-qualifiers -- don't warn about it.
-// ADDITIONAL_COMPILE_FLAGS: -Wno-ignored-qualifiers
+// ADDITIONAL_COMPILE_FLAGS(gcc-style-warnings): -Wno-ignored-qualifiers
 
 // template<class T>
 //     concept default_initializable = constructible_from<T> &&

libcxx/test/std/containers/associative/map/map.modifiers/insert_range.pass.cpp

@@ -8,7 +8,7 @@
 
 // UNSUPPORTED: c++03, c++11, c++14, c++17, c++20
 // Some fields in the test case variables are deliberately not explicitly initialized, this silences a warning on GCC.
-// ADDITIONAL_COMPILE_FLAGS: -Wno-missing-field-initializers
+// ADDITIONAL_COMPILE_FLAGS(gcc-style-warnings): -Wno-missing-field-initializers
 
 // <map>
 

libcxx/test/std/containers/associative/multimap/multimap.modifiers/insert_range.pass.cpp

@@ -8,7 +8,7 @@
 
 // UNSUPPORTED: c++03, c++11, c++14, c++17, c++20
 // Some fields in the test case variables are deliberately not explicitly initialized, this silences a warning on GCC.
-// ADDITIONAL_COMPILE_FLAGS: -Wno-missing-field-initializers
+// ADDITIONAL_COMPILE_FLAGS(gcc-style-warnings): -Wno-missing-field-initializers
 
 // <map>
 

libcxx/test/std/containers/associative/multiset/insert_range.pass.cpp

@@ -8,7 +8,7 @@
 
 // UNSUPPORTED: c++03, c++11, c++14, c++17, c++20
 // Some fields in the test case variables are deliberately not explicitly initialized, this silences a warning on GCC.
-// ADDITIONAL_COMPILE_FLAGS: -Wno-missing-field-initializers
+// ADDITIONAL_COMPILE_FLAGS(gcc-style-warnings): -Wno-missing-field-initializers
 
 // <set>
 

libcxx/test/std/containers/associative/set/insert_range.pass.cpp

@@ -8,7 +8,7 @@
 
 // UNSUPPORTED: c++03, c++11, c++14, c++17, c++20
 // Some fields in the test case variables are deliberately not explicitly initialized, this silences a warning on GCC.
-// ADDITIONAL_COMPILE_FLAGS: -Wno-missing-field-initializers
+// ADDITIONAL_COMPILE_FLAGS(gcc-style-warnings): -Wno-missing-field-initializers
 
 // <set>
 

libcxx/test/std/containers/sequences/array/array.tuple/get.verify.cpp

@@ -11,7 +11,7 @@
 // template <size_t I, class T, size_t N> T& get(array<T, N>& a);
 
 // Prevent -Warray-bounds from issuing a diagnostic when testing with clang verify.
-// ADDITIONAL_COMPILE_FLAGS: -Wno-array-bounds
+// ADDITIONAL_COMPILE_FLAGS(gcc-style-warnings): -Wno-array-bounds
 
 #include <array>
 #include <cassert>

libcxx/test/std/containers/unord/unord.map/unord.map.modifiers/insert_range.pass.cpp

@@ -8,7 +8,7 @@
 
 // UNSUPPORTED: c++03, c++11, c++14, c++17, c++20
 // Some fields in the test case variables are deliberately not explicitly initialized, this silences a warning on GCC.
-// ADDITIONAL_COMPILE_FLAGS: -Wno-missing-field-initializers
+// ADDITIONAL_COMPILE_FLAGS(gcc-style-warnings): -Wno-missing-field-initializers
 
 // <unordered_map>
 

libcxx/test/std/containers/unord/unord.multimap/unord.multimap.modifiers/insert_range.pass.cpp

@@ -8,7 +8,7 @@
 
 // UNSUPPORTED: c++03, c++11, c++14, c++17, c++20
 // Some fields in the test case variables are deliberately not explicitly initialized, this silences a warning on GCC.
-// ADDITIONAL_COMPILE_FLAGS: -Wno-missing-field-initializers
+// ADDITIONAL_COMPILE_FLAGS(gcc-style-warnings): -Wno-missing-field-initializers
 
 // <unordered_map>
 

libcxx/test/std/containers/unord/unord.multiset/insert_range.pass.cpp

@@ -8,7 +8,7 @@
 
 // UNSUPPORTED: c++03, c++11, c++14, c++17, c++20
 // Some fields in the test case variables are deliberately not explicitly initialized, this silences a warning on GCC.
-// ADDITIONAL_COMPILE_FLAGS: -Wno-missing-field-initializers
+// ADDITIONAL_COMPILE_FLAGS(gcc-style-warnings): -Wno-missing-field-initializers
 
 // <set>
 

libcxx/test/std/containers/unord/unord.set/insert_range.pass.cpp

@@ -8,7 +8,7 @@
 
 // UNSUPPORTED: c++03, c++11, c++14, c++17, c++20
 // Some fields in the test case variables are deliberately not explicitly initialized, this silences a warning on GCC.
-// ADDITIONAL_COMPILE_FLAGS: -Wno-missing-field-initializers
+// ADDITIONAL_COMPILE_FLAGS(gcc-style-warnings): -Wno-missing-field-initializers
 
 // <set>
 

libcxx/test/std/containers/views/mdspan/layout_stride/deduction.pass.cpp

@@ -6,7 +6,7 @@
 //
 //===----------------------------------------------------------------------===//
 // UNSUPPORTED: c++03, c++11, c++14, c++17, c++20
-// ADDITIONAL_COMPILE_FLAGS: -Wno-ctad-maybe-unsupported
+// ADDITIONAL_COMPILE_FLAGS(gcc-style-warnings): -Wno-ctad-maybe-unsupported
 
 // <mdspan>
 

libcxx/test/std/containers/views/mdspan/mdspan/conversion.pass.cpp

@@ -7,6 +7,9 @@
 //===----------------------------------------------------------------------===//
 // UNSUPPORTED: c++03, c++11, c++14, c++17, c++20
 
+// MSVC warning C4244: 'initializing': conversion from '_Ty' to '_Ty', possible loss of data
+// ADDITIONAL_COMPILE_FLAGS(cl-style-warnings): /wd4244
+
 // <mdspan>
 
 // template<class OtherElementType, class OtherExtents,

libcxx/test/std/depr/depr.c.headers/setjmp_h.compile.pass.cpp

@@ -6,6 +6,9 @@
 //
 //===----------------------------------------------------------------------===//
 
+// MSVC warning C4611: interaction between '_setjmp' and C++ object destruction is non-portable
+// ADDITIONAL_COMPILE_FLAGS(cl-style-warnings): /wd4611
+
 // test <setjmp.h>
 //
 // Even though <setjmp.h> is not provided by libc++, we still test that

libcxx/test/std/depr/depr.numeric.limits.has.denorm/deprecated.verify.cpp

@@ -8,7 +8,7 @@
 
 // UNSUPPORTED: c++03, c++11, c++14, c++17, c++20
 
-// ADDITIONAL_COMPILE_FLAGS: -Wno-unused-value
+// ADDITIONAL_COMPILE_FLAGS(gcc-style-warnings): -Wno-unused-value
 
 #include <limits>
 

libcxx/test/std/input.output/file.streams/fstreams/ifstream.members/buffered_reads.pass.cpp

@@ -7,6 +7,9 @@
 //===----------------------------------------------------------------------===//
 
 // ADDITIONAL_COMPILE_FLAGS: -D_LIBCPP_DISABLE_DEPRECATION_WARNINGS -D_LIBCPP_ENABLE_CXX26_REMOVED_CODECVT
+// MSVC warning C4242: '+=': conversion from 'const _Ty' to 'size_t', possible loss of data
+// MSVC warning C4244: 'argument': conversion from 'std::streamsize' to 'size_t', possible loss of data
+// ADDITIONAL_COMPILE_FLAGS(cl-style-warnings): /wd4242 /wd4244
 // UNSUPPORTED: c++03
 
 // <fstream>

libcxx/test/std/input.output/file.streams/fstreams/ofstream.members/buffered_writes.pass.cpp

@@ -7,6 +7,9 @@
 //===----------------------------------------------------------------------===//
 
 // ADDITIONAL_COMPILE_FLAGS: -D_LIBCPP_DISABLE_DEPRECATION_WARNINGS -D_LIBCPP_ENABLE_CXX26_REMOVED_CODECVT
+// MSVC warning C4242: '+=': conversion from 'const _Ty' to 'size_t', possible loss of data
+// MSVC warning C4244: 'argument': conversion from 'std::streamsize' to 'size_t', possible loss of data
+// ADDITIONAL_COMPILE_FLAGS(cl-style-warnings): /wd4242 /wd4244
 // UNSUPPORTED: c++03
 
 // <fstream>

libcxx/test/std/iterators/iterator.primitives/iterator.operations/advance.pass.cpp

@@ -27,7 +27,7 @@
 // <TODO:Remove brackets> below
 
 // Make sure we catch forced conversions to the difference_type if they happen.
-// ADDITIONAL_COMPILE_FLAGS<TODO:Remove brackets>: -Wsign-conversion
+// ADDITIONAL_COMPILE_FLAGS<TODO:Remove brackets>(gcc-style-warnings): -Wsign-conversion
 
 #include <iterator>
 #include <cassert>

libcxx/test/std/language.support/support.runtime/csetjmp.pass.cpp

@@ -6,6 +6,9 @@
 //
 //===----------------------------------------------------------------------===//
 
+// MSVC warning C4611: interaction between '_setjmp' and C++ object destruction is non-portable
+// ADDITIONAL_COMPILE_FLAGS(cl-style-warnings): /wd4611
+
 // test <csetjmp>
 
 #include <csetjmp>

libcxx/test/std/ranges/range.adaptors/range.lazy.split/constraints.compile.pass.cpp

@@ -8,6 +8,9 @@
 
 // UNSUPPORTED: c++03, c++11, c++14, c++17
 
+// This is a compile-only test, so "inline function is not defined" warnings are irrelevant.
+// ADDITIONAL_COMPILE_FLAGS(gcc-style-warnings): -Wno-undefined-inline
+
 // template<input_range V, forward_range Pattern>
 //   requires view<V> && view<Pattern> &&
 //            indirectly_comparable<iterator_t<V>, iterator_t<Pattern>, ranges::equal_to> &&

libcxx/test/std/ranges/range.utility/range.utility.conv/to.pass.cpp

@@ -6,6 +6,9 @@
 //
 //===----------------------------------------------------------------------===//
 
+// MSVC warning C4244: 'argument': conversion from '_Ty' to 'int', possible loss of data
+// ADDITIONAL_COMPILE_FLAGS(cl-style-warnings): /wd4244
+
 // UNSUPPORTED: c++03, c++11, c++14, c++17, c++20
 
 // template<class C, input_range R, class... Args> requires (!view<C>)

libcxx/test/std/strings/basic.string/string.cons/from_range_deduction.pass.cpp

@@ -10,7 +10,7 @@
 
 // UNSUPPORTED: c++03, c++11, c++14, c++17, c++20
 // To silence a GCC warning-turned-error re. `BadAlloc::value_type`.
-// ADDITIONAL_COMPILE_FLAGS: -Wno-unused-local-typedefs
+// ADDITIONAL_COMPILE_FLAGS(gcc-style-warnings): -Wno-unused-local-typedefs
 
 // template<ranges::input_range R,
 //          class Allocator = allocator<ranges::range_value_t<R>>>

libcxx/test/std/thread/thread.condition/notify_all_at_thread_exit_lwg3343.pass.cpp

@@ -35,13 +35,19 @@
 
 int condition_variable_lock_skipped_counter = 0;
 
+TEST_DIAGNOSTIC_PUSH
+// MSVC warning C4583: 'X::cv_': destructor is not implicitly called
+TEST_MSVC_DIAGNOSTIC_IGNORED(4583)
+
 union X {
     X() : cv_() {}
     ~X() {}
     std::condition_variable cv_;
     unsigned char bytes_[sizeof(std::condition_variable)];
 };
 
+TEST_DIAGNOSTIC_POP
+
 void test()
 {
     constexpr int N = 3;

libcxx/test/std/thread/thread.jthread/assign.move.pass.cpp

@@ -10,7 +10,7 @@
 // UNSUPPORTED: libcpp-has-no-experimental-stop_token
 // UNSUPPORTED: c++03, c++11, c++14, c++17
 // XFAIL: availability-synchronization_library-missing
-// ADDITIONAL_COMPILE_FLAGS: -Wno-self-move
+// ADDITIONAL_COMPILE_FLAGS(gcc-style-warnings): -Wno-self-move
 
 // jthread& operator=(jthread&&) noexcept;
 

libcxx/test/std/utilities/meta/meta.trans/meta.trans.other/result_of11.pass.cpp

@@ -23,9 +23,10 @@
 
 // Ignore warnings about volatile in parameters being deprecated.
 // We know it is, but we still have to test it.
-#if defined(TEST_COMPILER_GCC)
-#   pragma GCC diagnostic ignored "-Wvolatile"
-#endif
+TEST_CLANG_DIAGNOSTIC_IGNORED("-Wdeprecated-volatile")
+TEST_GCC_DIAGNOSTIC_IGNORED("-Wvolatile")
+// MSVC warning C5215: a function parameter with a volatile qualified type is deprecated in C++20
+TEST_MSVC_DIAGNOSTIC_IGNORED(5215)
 
 struct wat
 {
@@ -65,9 +66,6 @@ void test_result_of_imp()
 #endif
 }
 
-// Do not warn on deprecated uses of 'volatile' below.
-_LIBCPP_SUPPRESS_DEPRECATED_PUSH
-
 int main(int, char**)
 {
     {
@@ -184,5 +182,3 @@ int main(int, char**)
 
   return 0;
 }
-
-_LIBCPP_SUPPRESS_DEPRECATED_POP

libcxx/test/std/utilities/meta/meta.unary/dependent_return_type.compile.pass.cpp

@@ -11,7 +11,9 @@
 // UNSUPPORTED: c++03, c++11
 
 // ignore deprecated volatile return types
-// ADDITIONAL_COMPILE_FLAGS: -Wno-deprecated-volatile
+// ADDITIONAL_COMPILE_FLAGS(gcc-style-warnings): -Wno-deprecated-volatile
+// MSVC warning C5216: 'volatile int' a volatile qualified return type is deprecated in C++20
+// ADDITIONAL_COMPILE_FLAGS(cl-style-warnings): /wd5216
 
 #include <type_traits>
 #include <utility>

libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/unique.ptr.asgn/move.pass.cpp

@@ -9,7 +9,7 @@
 // UNSUPPORTED: c++03
 
 // Self assignment post-conditions are tested.
-// ADDITIONAL_COMPILE_FLAGS: -Wno-self-move
+// ADDITIONAL_COMPILE_FLAGS(gcc-style-warnings): -Wno-self-move
 
 // <memory>
 

libcxx/test/std/utilities/variant/variant.variant/implicit_ctad.pass.cpp

@@ -16,8 +16,8 @@
 
 // We make sure that it is not ill-formed, however we still produce a warning for
 // this one because explicit construction from a variant using CTAD is ambiguous
-// (in the sense that the programer intent is not clear).
-// ADDITIONAL_COMPILE_FLAGS: -Wno-ctad-maybe-unsupported
+// (in the sense that the programmer intent is not clear).
+// ADDITIONAL_COMPILE_FLAGS(gcc-style-warnings): -Wno-ctad-maybe-unsupported
 
 #include <variant>
 

libcxx/test/support/msvc_stdlib_force_include.h

@@ -104,14 +104,4 @@ const AssertionDialogAvoider assertion_dialog_avoider{};
 
 #define _LIBCPP_AVAILABILITY_THROW_BAD_ANY_CAST
 
-#ifdef __clang__
-#  define _LIBCPP_SUPPRESS_DEPRECATED_PUSH                                                                             \
-    _Pragma("GCC diagnostic push") _Pragma("GCC diagnostic ignored \"-Wdeprecated\"")
-#  define _LIBCPP_SUPPRESS_DEPRECATED_POP _Pragma("GCC diagnostic pop")
-#else // ^^^ clang / MSVC vvv
-#  define _LIBCPP_SUPPRESS_DEPRECATED_PUSH                                                                             \
-    __pragma(warning(push)) __pragma(warning(disable : 4996)) __pragma(warning(disable : 5215))
-#  define _LIBCPP_SUPPRESS_DEPRECATED_POP __pragma(warning(pop))
-#endif // __clang__
-
 #endif // SUPPORT_MSVC_STDLIB_FORCE_INCLUDE_H