From 417be15231cb34a2e858d26b63406d1fb5535cb9 Mon Sep 17 00:00:00 2001
From: Boris Kolpackov <boris@codesynthesis.com>
Date: Thu, 2 Mar 2023 15:38:15 +0200
Subject: Replace deprecated std::aligned_storage with alignas

Based on patch by Matthew Krupcale.
---
 libbuild2/function.hxx  |  9 +++++----
 libbuild2/scheduler.hxx |  5 +++--
 libbuild2/target.hxx    |  8 ++++----
 libbuild2/variable.cxx  | 10 +++++-----
 libbuild2/variable.hxx  |  7 ++++---
 5 files changed, 21 insertions(+), 18 deletions(-)

diff --git a/libbuild2/function.hxx b/libbuild2/function.hxx
index 323ac41..cda856a 100644
--- a/libbuild2/function.hxx
+++ b/libbuild2/function.hxx
@@ -4,8 +4,9 @@
 #ifndef LIBBUILD2_FUNCTION_HXX
 #define LIBBUILD2_FUNCTION_HXX
 
-#include <utility>       // index_sequence
-#include <type_traits>   // aligned_storage
+#include <cstddef>      // max_align_t
+#include <utility>      // index_sequence
+#include <type_traits>  // is_*
 
 #include <libbuild2/types.hxx>
 #include <libbuild2/forward.hxx>
@@ -133,8 +134,8 @@ namespace build2
     // Auxiliary data storage. Note that it is expected to be trivially
     // copyable and destructible.
     //
-    std::aligned_storage<sizeof (void*) * 3>::type data;
-    static const size_t data_size = sizeof (decltype (data));
+    static const size_t data_size = sizeof (void*) * 3;
+    alignas (std::max_align_t) unsigned char data[data_size];
 
     function_overload (const char* an,
                        size_t mi, size_t ma, types ts,
diff --git a/libbuild2/scheduler.hxx b/libbuild2/scheduler.hxx
index c34d41b..b579d80 100644
--- a/libbuild2/scheduler.hxx
+++ b/libbuild2/scheduler.hxx
@@ -7,7 +7,8 @@
 #include <list>
 #include <tuple>
 #include <atomic>
-#include <type_traits>        // aligned_storage, etc
+#include <cstddef>     // max_align_t
+#include <type_traits> // decay, etc
 
 #include <libbuild2/types.hxx>
 #include <libbuild2/utility.hxx>
@@ -681,7 +682,7 @@ namespace build2
     //
     struct task_data
     {
-      std::aligned_storage<sizeof (void*) * 8>::type data;
+      alignas (std::max_align_t) unsigned char data[sizeof (void*) * 8];
       void (*thunk) (scheduler&, lock&, void*);
     };
 
diff --git a/libbuild2/target.hxx b/libbuild2/target.hxx
index 26c7208..037b18c 100644
--- a/libbuild2/target.hxx
+++ b/libbuild2/target.hxx
@@ -4,8 +4,9 @@
 #ifndef LIBBUILD2_TARGET_HXX
 #define LIBBUILD2_TARGET_HXX
 
+#include <cstddef>      // max_align_t
 #include <iterator>     // tags, etc.
-#include <type_traits>  // aligned_storage
+#include <type_traits>  // is_*
 #include <unordered_map>
 
 #include <libbutl/multi-index.hxx> // map_iterator_adapter
@@ -189,7 +190,7 @@ namespace build2
                                          ? sizeof (string)
                                          : sizeof (void*) * 4);
 
-    std::aligned_storage<data_size>::type data_;
+    alignas (std::max_align_t) unsigned char data_[data_size];
     void (*data_dtor_) (void*) = nullptr;
 
     template <typename R,
@@ -1624,8 +1625,7 @@ namespace build2
       group_view g_;
       size_t j_;        // 1-based index, to support enter_group().
       const target* k_; // Current member of ad hoc group or NULL.
-      mutable typename std::aligned_storage<sizeof (value_type),
-                                            alignof (value_type)>::type m_;
+      alignas (value_type) mutable unsigned char m_[sizeof (value_type)];
     };
 
     iterator
diff --git a/libbuild2/variable.cxx b/libbuild2/variable.cxx
index 260d664..d55737b 100644
--- a/libbuild2/variable.cxx
+++ b/libbuild2/variable.cxx
@@ -3,7 +3,7 @@
 
 #include <libbuild2/variable.hxx>
 
-#include <cstring> // memcmp()
+#include <cstring> // memcmp(), memcpy()
 
 #include <libbutl/path-pattern.hxx>
 
@@ -57,7 +57,7 @@ namespace build2
       else if (type->copy_ctor != nullptr)
         type->copy_ctor (*this, v, true);
       else
-        data_ = v.data_; // Copy as POD.
+        memcpy (data_, v.data_, size_); // Copy as POD.
     }
   }
 
@@ -72,7 +72,7 @@ namespace build2
       else if (type->copy_ctor != nullptr)
         type->copy_ctor (*this, v, false);
       else
-        data_ = v.data_; // Copy as POD.
+        memcpy (data_, v.data_, size_); // Copy as POD.
     }
   }
 
@@ -106,7 +106,7 @@ namespace build2
         else if (auto f = null ? type->copy_ctor : type->copy_assign)
           f (*this, v, true);
         else
-          data_ = v.data_; // Assign as POD.
+          memcpy (data_, v.data_, size_); // Assign as POD.
 
         null = v.null;
       }
@@ -145,7 +145,7 @@ namespace build2
         else if (auto f = null ? type->copy_ctor : type->copy_assign)
           f (*this, v, false);
         else
-          data_ = v.data_; // Assign as POD.
+          memcpy (data_, v.data_, size_); // Assign as POD.
 
         null = v.null;
       }
diff --git a/libbuild2/variable.hxx b/libbuild2/variable.hxx
index 8a0adf8..b137789 100644
--- a/libbuild2/variable.hxx
+++ b/libbuild2/variable.hxx
@@ -4,7 +4,8 @@
 #ifndef LIBBUILD2_VARIABLE_HXX
 #define LIBBUILD2_VARIABLE_HXX
 
-#include <type_traits>   // aligned_storage
+#include <cstddef>       // max_align_t
+#include <type_traits>   // is_*
 #include <unordered_map>
 
 #include <libbutl/prefix-map.hxx>
@@ -423,8 +424,8 @@ namespace build2
     // specialization below). Types that don't fit will have to be handled
     // with an extra dynamic allocation.
     //
-    static constexpr size_t           size_ = sizeof (name_pair);
-    std::aligned_storage<size_>::type data_;
+    static constexpr size_t size_ = sizeof (name_pair);
+    alignas (std::max_align_t) unsigned char data_[size_];
 
     // Make sure we have sufficient storage for untyped values.
     //
-- 
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