[libcxx-commits] [PATCH] D133661: [libc++] Improve binary size when using __transaction

[Nikolas Klauser via Phabricator via libcxx-commits]

philnik created this revision.
philnik added reviewers: ldionne, Mordante, var-const, huixie90.
Herald added a project: All.
philnik requested review of this revision.
Herald added a project: libc++.
Herald added a subscriber: libcxx-commits.
Herald added a reviewer: libc++.

Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D133661

Files:
  libcxx/include/__memory/uninitialized_algorithms.h
  libcxx/include/__utility/transaction.h


Index: libcxx/include/__utility/transaction.h
===================================================================
--- libcxx/include/__utility/transaction.h
+++ libcxx/include/__utility/transaction.h
@@ -47,6 +47,8 @@
 //        return out;
 //    }
 //
+
+#ifndef _LIBCPP_NO_EXCEPTIONS
 template <class _Rollback>
 struct __transaction {
     __transaction() = delete;
@@ -85,6 +87,21 @@
     _Rollback __rollback_;
     bool __completed_;
 };
+#else
+template <class _Rollback>
+struct __transaction {
+  __transaction() = delete;
+  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 _LIBCPP_NODEBUG __transaction(_Rollback) {}
+  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 _LIBCPP_NODEBUG __transaction(__transaction&&)
+      _NOEXCEPT_(is_nothrow_move_constructible<_Rollback>::value) {}
+  __transaction(const __transaction&) = delete;
+  __transaction& operator=(const __transaction&) = delete;
+  __transaction& operator=(__transaction&&) = delete;
+
+  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 _LIBCPP_NODEBUG void __complete() _NOEXCEPT {}
+  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 _LIBCPP_NODEBUG ~__transaction() {}
+};
+#endif
 
 template <class _Rollback>
 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR __transaction<_Rollback> __make_transaction(_Rollback __rollback) {
Index: libcxx/include/__memory/uninitialized_algorithms.h
===================================================================
--- libcxx/include/__memory/uninitialized_algorithms.h
+++ libcxx/include/__memory/uninitialized_algorithms.h
@@ -534,19 +534,14 @@
 __uninitialized_allocator_copy(_Alloc& __alloc, _Iter1 __first1, _Sent1 __last1, _Iter2 __first2) {
 #ifndef _LIBCPP_NO_EXCEPTIONS
   auto __destruct_first = __first2;
-  try {
-#endif
+  auto __guard =
+      std::__make_transaction(_AllocatorDestroyRangeReverse<_Alloc, _Iter2>(__alloc, __destruct_first, __first2));
   while (__first1 != __last1) {
     allocator_traits<_Alloc>::construct(__alloc, std::__to_address(__first2), *__first1);
     ++__first1;
     ++__first2;
   }
-#ifndef _LIBCPP_NO_EXCEPTIONS
-  } catch (...) {
-    _AllocatorDestroyRangeReverse<_Alloc, _Iter2>(__alloc, __destruct_first, __first2)();
-    throw;
-  }
-#endif
+  __guard.__complete();
   return __first2;
 }
 
@@ -588,10 +583,9 @@
     _Alloc& __alloc, _Iter1 __first1, _Sent1 __last1, _Iter2 __first2) {
   static_assert(__is_cpp17_move_insertable<_Alloc>::value,
                 "The specified type does not meet the requirements of Cpp17MoveInsertable");
-#ifndef _LIBCPP_NO_EXCEPTIONS
   auto __destruct_first = __first2;
-  try {
-#endif
+  auto __guard =
+      std::__make_transaction(_AllocatorDestroyRangeReverse<_Alloc, _Iter2>(__alloc, __destruct_first, __first2));
   while (__first1 != __last1) {
 #ifndef _LIBCPP_NO_EXCEPTIONS
     allocator_traits<_Alloc>::construct(__alloc, std::__to_address(__first2), std::move_if_noexcept(*__first1));
@@ -601,12 +595,7 @@
     ++__first1;
     ++__first2;
   }
-#ifndef _LIBCPP_NO_EXCEPTIONS
-  } catch (...) {
-    _AllocatorDestroyRangeReverse<_Alloc, _Iter2>(__alloc, __destruct_first, __first2)();
-    throw;
-  }
-#endif
+  __guard.__complete();
   return __first2;
 }
 


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