[libcxx-commits] [libcxx] [z/OS][libc++] Guard to be used only when `align_val_t` is available (PR #114396)

[Zibi Sarbinowski via libcxx-commits]

https://github.com/zibi2 updated https://github.com/llvm/llvm-project/pull/114396

>From a83b5caf569b1aabfe347f5d84f6a2c9f518333e Mon Sep 17 00:00:00 2001
From: Zbigniew Sarbinowski <zibi at ca.ibm.com>
Date: Thu, 31 Oct 2024 12:08:18 +0000
Subject: [PATCH 1/2] Guard  to be used only when they are available

---
 libcxx/include/__utility/small_buffer.h | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/libcxx/include/__utility/small_buffer.h b/libcxx/include/__utility/small_buffer.h
index 70e068f89f62ed..6071bda4513657 100644
--- a/libcxx/include/__utility/small_buffer.h
+++ b/libcxx/include/__utility/small_buffer.h
@@ -61,6 +61,7 @@ class __small_buffer {
       return *std::launder(reinterpret_cast<_Stored**>(__buffer_));
   }
 
+#  ifdef _LIBCPP_HAS_LIBRARY_ALIGNED_ALLOCATION
   template <class _Stored>
   _LIBCPP_HIDE_FROM_ABI _Stored* __alloc() {
     if constexpr (__fits_in_buffer<_Stored>) {
@@ -72,11 +73,14 @@ class __small_buffer {
     }
   }
 
+#  endif // _LIBCPP_HAS_LIBRARY_ALIGNED_ALLOCATION
+#  ifdef _LIBCPP_HAS_LIBRARY_SIZED_DEALLOCATION
   template <class _Stored>
   _LIBCPP_HIDE_FROM_ABI void __dealloc() noexcept {
     if constexpr (!__fits_in_buffer<_Stored>)
       ::operator delete[](*reinterpret_cast<void**>(__buffer_), sizeof(_Stored), align_val_t{alignof(_Stored)});
   }
+#  endif // _LIBCPP_HAS_LIBRARY_SIZED_DEALLOCATION
 
   template <class _Stored, class... _Args>
   _LIBCPP_HIDE_FROM_ABI void __construct(_Args&&... __args) {

>From ff95378feeb7ef5790aa7d3f14f409d61d11300d Mon Sep 17 00:00:00 2001
From: Zbigniew Sarbinowski <zibi at ca.ibm.com>
Date: Thu, 31 Oct 2024 19:49:21 +0000
Subject: [PATCH 2/2] Add __libcpp_allocate and __libcpp_deallocate in the
 absense of align allocation and sized deallocation

---
 libcxx/include/__utility/small_buffer.h | 12 ++++++++----
 1 file changed, 8 insertions(+), 4 deletions(-)

diff --git a/libcxx/include/__utility/small_buffer.h b/libcxx/include/__utility/small_buffer.h
index 6071bda4513657..a99df30e80c794 100644
--- a/libcxx/include/__utility/small_buffer.h
+++ b/libcxx/include/__utility/small_buffer.h
@@ -61,26 +61,30 @@ class __small_buffer {
       return *std::launder(reinterpret_cast<_Stored**>(__buffer_));
   }
 
-#  ifdef _LIBCPP_HAS_LIBRARY_ALIGNED_ALLOCATION
   template <class _Stored>
   _LIBCPP_HIDE_FROM_ABI _Stored* __alloc() {
     if constexpr (__fits_in_buffer<_Stored>) {
       return std::launder(reinterpret_cast<_Stored*>(__buffer_));
     } else {
+#  ifdef _LIBCPP_HAS_LIBRARY_ALIGNED_ALLOCATION
       byte* __allocation = static_cast<byte*>(::operator new[](sizeof(_Stored), align_val_t{alignof(_Stored)}));
       std::construct_at(reinterpret_cast<byte**>(__buffer_), __allocation);
       return std::launder(reinterpret_cast<_Stored*>(__allocation));
+#  else
+      return static_cast<_Stored*>(std::__libcpp_allocate(_BufferSize* sizeof(byte), _LIBCPP_ALIGNOF(byte)));
+#  endif // _LIBCPP_HAS_LIBRARY_ALIGNED_ALLOCATION
     }
   }
 
-#  endif // _LIBCPP_HAS_LIBRARY_ALIGNED_ALLOCATION
-#  ifdef _LIBCPP_HAS_LIBRARY_SIZED_DEALLOCATION
   template <class _Stored>
   _LIBCPP_HIDE_FROM_ABI void __dealloc() noexcept {
     if constexpr (!__fits_in_buffer<_Stored>)
+#  ifdef _LIBCPP_HAS_LIBRARY_SIZED_DEALLOCATION
       ::operator delete[](*reinterpret_cast<void**>(__buffer_), sizeof(_Stored), align_val_t{alignof(_Stored)});
-  }
+#  else
+      std::__libcpp_deallocate((void*)__buffer_, _BufferSize * sizeof(byte), _LIBCPP_ALIGNOF(_Stored));
 #  endif // _LIBCPP_HAS_LIBRARY_SIZED_DEALLOCATION
+  }
 
   template <class _Stored, class... _Args>
   _LIBCPP_HIDE_FROM_ABI void __construct(_Args&&... __args) {