From 34a006eaa39ceb6b0a96fa386c9b9b8a44681979 Mon Sep 17 00:00:00 2001 From: Alex Richardson Date: Mon, 15 Sep 2025 15:14:18 -0700 Subject: [PATCH] libc++: silence -Wnontrivial-memaccess warning with newer clang Apply part of LLVM commit 71315698c91d0cda054b903da0594ca6f072c350 to silence the -Wnontrivial-memaccess warning that is triggered any time this function is instantiated by user code. This fixes another buildworld failure with Clang HEAD. Original commit message: [clang] Warn about memset/memcpy to NonTriviallyCopyable types (#111434) This implements a warning that's similar to what GCC does in that context: both memcpy and memset require their first and second operand to be trivially copyable, let's warn if that's not the case. Reviewed by: emaste, dim MFC after: 1 week Differential Revision: https://reviews.freebsd.org/D52534 --- .../libcxx/include/__memory/uninitialized_algorithms.h | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/contrib/llvm-project/libcxx/include/__memory/uninitialized_algorithms.h b/contrib/llvm-project/libcxx/include/__memory/uninitialized_algorithms.h index 7475ef5cf85d..79cab80dcf73 100644 --- a/contrib/llvm-project/libcxx/include/__memory/uninitialized_algorithms.h +++ b/contrib/llvm-project/libcxx/include/__memory/uninitialized_algorithms.h @@ -642,7 +642,8 @@ __uninitialized_allocator_relocate(_Alloc& __alloc, _Tp* __first, _Tp* __last, _ __guard.__complete(); std::__allocator_destroy(__alloc, __first, __last); } else { - __builtin_memcpy(const_cast<__remove_const_t<_Tp>*>(__result), __first, sizeof(_Tp) * (__last - __first)); + // Casting to void* to suppress clang complaining that this is technically UB. + __builtin_memcpy(static_cast(const_cast<__remove_const_t<_Tp>*>(__result)), __first, sizeof(_Tp) * (__last - __first)); } }