[libc++] Bump Xcode support (#148651)

ldionne · web-flow · commit d145f716aefc · 2025-07-15T10:45:37.000-04:00
Libc++'s policy is to support only the latest released Xcode, which is
Xcode 16.x. We did update our CI jobs to Xcode 16.x, but we forgot to
update the documentation, which still mentioned Xcode 15. This patch
updates the documentation and cleans up outdated mentions of
apple-clang-15 in the test suite.
diff --git a/libcxx/docs/index.rst b/libcxx/docs/index.rst
@@ -133,7 +133,7 @@ velocity, libc++ drops support for older compilers as newer ones are released.
 Compiler     Versions            Restrictions               Support policy
 ============ =================== ========================== =====================
 Clang        19, 20, 21-git                                 latest two stable releases per `LLVM's release page <https://releases.llvm.org>`_ and the development version
-AppleClang   15                                             latest stable release per `Xcode's release page <https://developer.apple.com/documentation/xcode-release-notes>`_
+AppleClang   16.4                                           latest stable release per `Xcode's release page <https://developer.apple.com/documentation/xcode-release-notes>`_
 Open XL      17.1.3 (AIX)                                   latest stable release per `Open XL's documentation page <https://www.ibm.com/docs/en/openxl-c-and-cpp-aix>`_
 GCC          15                  In C++11 or later only     latest stable release per `GCC's release page <https://gcc.gnu.org/releases.html>`_
 ============ =================== ========================== =====================
diff --git a/libcxx/include/__algorithm/simd_utils.h b/libcxx/include/__algorithm/simd_utils.h
@@ -26,9 +26,7 @@ _LIBCPP_PUSH_MACROS
 #include <__undef_macros>
 
 // TODO: Find out how altivec changes things and allow vectorizations there too.
-// TODO: Simplify this condition once we stop building with AppleClang 15 in the CI.
-#if _LIBCPP_STD_VER >= 14 && defined(_LIBCPP_COMPILER_CLANG_BASED) && !defined(__ALTIVEC__) &&                         \
-    !(defined(_LIBCPP_APPLE_CLANG_VER) && _LIBCPP_APPLE_CLANG_VER < 1600)
+#if _LIBCPP_STD_VER >= 14 && defined(_LIBCPP_COMPILER_CLANG_BASED) && !defined(__ALTIVEC__)
 #  define _LIBCPP_HAS_ALGORITHM_VECTOR_UTILS 1
 #else
 #  define _LIBCPP_HAS_ALGORITHM_VECTOR_UTILS 0
diff --git a/libcxx/include/__configuration/compiler.h b/libcxx/include/__configuration/compiler.h
@@ -37,7 +37,7 @@
 #      warning "Libc++ only supports Clang 19 and later"
 #    endif
 #  elif defined(_LIBCPP_APPLE_CLANG_VER)
-#    if _LIBCPP_APPLE_CLANG_VER < 1500
+#    if _LIBCPP_APPLE_CLANG_VER < 1600
 #      warning "Libc++ only supports AppleClang 15 and later"
 #    endif
 #  elif defined(_LIBCPP_GCC_VER)
diff --git a/libcxx/test/libcxx/algorithms/vectorization.compile.pass.cpp b/libcxx/test/libcxx/algorithms/vectorization.compile.pass.cpp
@@ -17,9 +17,6 @@
 // We don't vectorize algorithms on AIX right now.
 // XFAIL: target={{.+}}-aix{{.*}}
 
-// We don't vectorize on AppleClang 15 since that apparently breaks std::mismatch
-// XFAIL: apple-clang-15
-
 // This test ensures that we enable the vectorization of algorithms on the expected
 // platforms.
 
diff --git a/libcxx/test/libcxx/memory/shared_ptr_array.pass.cpp b/libcxx/test/libcxx/memory/shared_ptr_array.pass.cpp
@@ -12,7 +12,6 @@
 // These compiler versions and platforms don't enable sized deallocation by default.
 // ADDITIONAL_COMPILE_FLAGS(clang-17): -fsized-deallocation
 // ADDITIONAL_COMPILE_FLAGS(clang-18): -fsized-deallocation
-// ADDITIONAL_COMPILE_FLAGS(apple-clang-15): -fsized-deallocation
 // ADDITIONAL_COMPILE_FLAGS(apple-clang-16): -fsized-deallocation
 // ADDITIONAL_COMPILE_FLAGS(target=x86_64-w64-windows-gnu): -fsized-deallocation
 // ADDITIONAL_COMPILE_FLAGS(target=i686-w64-windows-gnu): -fsized-deallocation
diff --git a/libcxx/test/libcxx/vendor/apple/disable-availability.sh.cpp b/libcxx/test/libcxx/vendor/apple/disable-availability.sh.cpp
@@ -8,10 +8,6 @@
 
 // REQUIRES: stdlib=apple-libc++
 
-// This test is dependent on the code generated by the compiler, and it doesn't
-// work properly with older AppleClangs.
-// UNSUPPORTED: apple-clang-15
-
 // This test ensures that we retain a way to disable availability markup on Apple platforms
 // in order to work around Clang bug https://github.com/llvm/llvm-project/issues/134151.
 //
diff --git a/libcxx/test/std/experimental/simd/simd.class/simd_unary.pass.cpp b/libcxx/test/std/experimental/simd/simd.class/simd_unary.pass.cpp
@@ -12,9 +12,6 @@
 //   Pass-by-value arguments with alignment greater than register width are not supported.
 // XFAIL: target=powerpc{{.*}}-ibm-{{.*}} && clang-18
 
-// This test crashes AppleClang 15 but not later versions.
-// UNSUPPORTED: apple-clang-15
-
 // FIXME: The following issue occurs on Windows to Armv7 Ubuntu Linux:
 //   Assertion failed: N->getValueType(0) == MVT::v1i1 && "Expected v1i1 type"
 // XFAIL: target=armv7-unknown-linux-gnueabihf
diff --git a/libcxx/test/std/language.support/support.dynamic/new.delete/new.delete.array/sized_delete_array.pass.cpp b/libcxx/test/std/language.support/support.dynamic/new.delete/new.delete.array/sized_delete_array.pass.cpp
@@ -12,7 +12,6 @@
 
 // These compiler versions and platforms don't enable sized deallocation by default.
 // ADDITIONAL_COMPILE_FLAGS(clang-18): -fsized-deallocation
-// ADDITIONAL_COMPILE_FLAGS(apple-clang-15): -fsized-deallocation
 // ADDITIONAL_COMPILE_FLAGS(apple-clang-16): -fsized-deallocation
 // ADDITIONAL_COMPILE_FLAGS(apple-clang-17): -fsized-deallocation
 // ADDITIONAL_COMPILE_FLAGS(target=x86_64-w64-windows-gnu): -fsized-deallocation
diff --git a/libcxx/test/std/language.support/support.dynamic/new.delete/new.delete.single/sized_delete.pass.cpp b/libcxx/test/std/language.support/support.dynamic/new.delete/new.delete.single/sized_delete.pass.cpp
@@ -12,7 +12,6 @@
 
 // These compiler versions and platforms don't enable sized deallocation by default.
 // ADDITIONAL_COMPILE_FLAGS(clang-18): -fsized-deallocation
-// ADDITIONAL_COMPILE_FLAGS(apple-clang-15): -fsized-deallocation
 // ADDITIONAL_COMPILE_FLAGS(apple-clang-16): -fsized-deallocation
 // ADDITIONAL_COMPILE_FLAGS(apple-clang-17): -fsized-deallocation
 // ADDITIONAL_COMPILE_FLAGS(target=x86_64-w64-windows-gnu): -fsized-deallocation
diff --git a/libcxx/test/std/numerics/c.math/signbit.pass.cpp b/libcxx/test/std/numerics/c.math/signbit.pass.cpp
@@ -12,7 +12,7 @@
 // UNSUPPORTED: windows
 
 // These compilers don't support constexpr `__builtin_signbit` yet.
-// UNSUPPORTED: clang-18, clang-19, apple-clang-15, apple-clang-16, apple-clang-17
+// UNSUPPORTED: clang-18, clang-19, apple-clang-16, apple-clang-17
 
 // GCC warns about signbit comparing `bool_v < 0`, which we're testing
 // ADDITIONAL_COMPILE_FLAGS(gcc): -Wno-bool-compare
diff --git a/libcxx/test/std/numerics/numeric.ops/numeric.ops.sat/add_sat.pass.cpp b/libcxx/test/std/numerics/numeric.ops/numeric.ops.sat/add_sat.pass.cpp
@@ -9,7 +9,7 @@
 // REQUIRES: std-at-least-c++26
 
 // The test uses "Placeholder variables with no name"
-// UNSUPPORTED: apple-clang-15, apple-clang-16
+// UNSUPPORTED: apple-clang-16
 
 // <numeric>
 
diff --git a/libcxx/test/std/numerics/numeric.ops/numeric.ops.sat/div_sat.pass.cpp b/libcxx/test/std/numerics/numeric.ops/numeric.ops.sat/div_sat.pass.cpp
@@ -9,7 +9,7 @@
 // REQUIRES: std-at-least-c++26
 
 // The test uses "Placeholder variables with no name"
-// UNSUPPORTED: apple-clang-15, apple-clang-16
+// UNSUPPORTED: apple-clang-16
 
 // <numeric>
 
diff --git a/libcxx/test/std/numerics/numeric.ops/numeric.ops.sat/mul_sat.pass.cpp b/libcxx/test/std/numerics/numeric.ops/numeric.ops.sat/mul_sat.pass.cpp
@@ -9,7 +9,7 @@
 // REQUIRES: std-at-least-c++26
 
 // The test uses "Placeholder variables with no name"
-// UNSUPPORTED: apple-clang-15, apple-clang-16
+// UNSUPPORTED: apple-clang-16
 
 // <numeric>
 
diff --git a/libcxx/test/std/numerics/numeric.ops/numeric.ops.sat/saturate_cast.pass.cpp b/libcxx/test/std/numerics/numeric.ops/numeric.ops.sat/saturate_cast.pass.cpp
@@ -9,7 +9,7 @@
 // REQUIRES: std-at-least-c++26
 
 // The test uses "Placeholder variables with no name"
-// UNSUPPORTED: apple-clang-15, apple-clang-16
+// UNSUPPORTED: apple-clang-16
 
 // <numeric>
 
diff --git a/libcxx/test/std/numerics/numeric.ops/numeric.ops.sat/sub_sat.pass.cpp b/libcxx/test/std/numerics/numeric.ops/numeric.ops.sat/sub_sat.pass.cpp
@@ -9,7 +9,7 @@
 // REQUIRES: std-at-least-c++26
 
 // The test uses "Placeholder variables with no name"
-// UNSUPPORTED: apple-clang-15, apple-clang-16
+// UNSUPPORTED: apple-clang-16
 
 // <numeric>
 
diff --git a/libcxx/test/std/ranges/range.utility/range.utility.conv/to_deduction.pass.cpp b/libcxx/test/std/ranges/range.utility/range.utility.conv/to_deduction.pass.cpp
@@ -7,9 +7,6 @@
 //===----------------------------------------------------------------------===//
 
 // UNSUPPORTED: c++03, c++11, c++14, c++17, c++20
-// There is a bug in older versions of Clang that causes trouble with constraints in classes like
-// `ContainerWithDirectCtr`.
-// XFAIL: apple-clang-15
 
 // template<template<class...> class C, input_range R, class... Args>
 //   constexpr auto to(R&& r, Args&&... args);  // Since C++23
diff --git a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_implicit_lifetime.pass.cpp b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_implicit_lifetime.pass.cpp
@@ -9,7 +9,7 @@
 // UNSUPPORTED: c++03, c++11, c++14, c++17, c++20
 
 // These compilers don't support __builtin_is_implicit_lifetime yet.
-// UNSUPPORTED: clang-18, clang-19, gcc-14, gcc-15, apple-clang-15, apple-clang-16, apple-clang-17
+// UNSUPPORTED: clang-18, clang-19, gcc-14, gcc-15, apple-clang-16, apple-clang-17
 
 // <type_traits>
 
diff --git a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_implicit_lifetime.verify.cpp b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_implicit_lifetime.verify.cpp
@@ -9,7 +9,7 @@
 // UNSUPPORTED: c++03, c++11, c++14, c++17, c++20
 
 // These compilers don't support __builtin_is_implicit_lifetime yet.
-// UNSUPPORTED: clang-18, clang-19, gcc-14, apple-clang-15, apple-clang-16, apple-clang-17
+// UNSUPPORTED: clang-18, clang-19, gcc-14, apple-clang-16, apple-clang-17
 
 // <type_traits>
 
diff --git a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/reference_constructs_from_temporary.pass.cpp b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/reference_constructs_from_temporary.pass.cpp
@@ -9,7 +9,7 @@
 // REQUIRES: std-at-least-c++23
 
 // These compilers don't support std::reference_converts_from_temporary yet.
-// UNSUPPORTED: android, apple-clang-15, apple-clang-16, clang-19.1
+// UNSUPPORTED: android, apple-clang-16, clang-19.1
 
 // <type_traits>
 
diff --git a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/reference_converts_from_temporary.pass.cpp b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/reference_converts_from_temporary.pass.cpp
@@ -9,7 +9,7 @@
 // REQUIRES: std-at-least-c++23
 
 // These compilers don't support std::reference_converts_from_temporary yet.
-// UNSUPPORTED: android, apple-clang-15, apple-clang-16, clang-18, clang-19.1
+// UNSUPPORTED: android, apple-clang-16, clang-18, clang-19.1
 
 // <type_traits>
 
