[libcxx-commits] [libcxx] [libc++] Fix "leak" of PMR resource in benchmark (PR #216114)

[Nikolas Klauser via libcxx-commits]

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@@ -135,30 +135,35 @@ void associative_container_benchmarks(std::string container) {
     using PMRContainer = adapt_operations<Container>::template rebind_alloc<
         std::pmr::polymorphic_allocator<typename Container::value_type>>;
 
+    struct alignas(PMRContainer) PMRScratchSpace {
+      char storage[sizeof(PMRContainer)];
+    };
+
     const std::size_t size = st.range(0);
     std::vector<Value> in  = make_value_types(generate_unique_keys(size));
     std::pmr::monotonic_buffer_resource rs(size * 64 * BatchSize); // 64 bytes should be enough per node
     std::vector<PMRContainer> srcs;
     srcs.reserve(BatchSize);
-    for (size_t i = 0; i != BatchSize; ++i)
+    for (std::size_t i = 0; i != BatchSize; ++i)
       srcs.emplace_back(&rs).insert(in.begin(), in.end());
-    alignas(PMRContainer) char c[BatchSize * sizeof(PMRContainer)];
+    PMRScratchSpace c[BatchSize];
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philnik777 wrote:

Can't we just have a union with an array inside it instead?

https://github.com/llvm/llvm-project/pull/216114