[Lldb-commits] [lldb] [WIP][lldb][test] Add a layout simulator test for std::unique_ptr (PR #98330)

[Pavel Labath via lldb-commits]

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@@ -0,0 +1,89 @@
+#ifndef STD_LLDB_COMPRESSED_PAIR_H
+#define STD_LLDB_COMPRESSED_PAIR_H
+
+#include <__memory/compressed_pair.h>
+#include <type_traits>
+
+namespace std {
+namespace __lldb {
+
+#if COMPRESSED_PAIR_REV == 0 // Post-c88580c layout
+struct __value_init_tag {};
+struct __default_init_tag {};
+
+template <class _Tp, int _Idx,
+          bool _CanBeEmptyBase =
+              std::is_empty<_Tp>::value && !std::is_final<_Tp>::value>
+struct __compressed_pair_elem {
+  explicit __compressed_pair_elem(__default_init_tag) {}
+  explicit __compressed_pair_elem(__value_init_tag) : __value_() {}
+
+  explicit __compressed_pair_elem(_Tp __t) : __value_(__t) {}
+
+  _Tp &__get() { return __value_; }
+
+private:
+  _Tp __value_;
+};
+
+template <class _Tp, int _Idx>
+struct __compressed_pair_elem<_Tp, _Idx, true> : private _Tp {
+  explicit __compressed_pair_elem(_Tp __t) : _Tp(__t) {}
+  explicit __compressed_pair_elem(__default_init_tag) {}
+  explicit __compressed_pair_elem(__value_init_tag) : _Tp() {}
+
+  _Tp &__get() { return *this; }
+};
+
+template <class _T1, class _T2>
+class __compressed_pair : private __compressed_pair_elem<_T1, 0>,
+                          private __compressed_pair_elem<_T2, 1> {
+public:
+  using _Base1 = __compressed_pair_elem<_T1, 0>;
+  using _Base2 = __compressed_pair_elem<_T2, 1>;
+
+  explicit __compressed_pair(_T1 __t1, _T2 __t2) : _Base1(__t1), _Base2(__t2) {}
+  explicit __compressed_pair()
+      : _Base1(__value_init_tag()), _Base2(__value_init_tag()) {}
+
+  template <class _U1, class _U2>
+  explicit __compressed_pair(_U1 &&__t1, _U2 &&__t2)
+      : _Base1(std::forward<_U1>(__t1)), _Base2(std::forward<_U2>(__t2)) {}
+
+  _T1 &first() { return static_cast<_Base1 &>(*this).__get(); }
+};
+#elif COMPRESSED_PAIR_REV == 1
+#define _LLDB_COMPRESSED_PAIR(T1, Initializer1, T2, Initializer2)              \
+  [[__gnu__::__aligned__(alignof(T2))]] [[no_unique_address]] T1 Initializer1; \
+  [[no_unique_address]] __compressed_pair_padding<T1> _LIBCPP_CONCAT3(         \
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labath wrote:

I'm also not sure if we really need the _LIBCPP_CONCAT3 concat thing. Since its going to produce nondeterministic (well deterministic, but they will change very easily) values, we can't really rely on it anywhere, so maybe we could just hardcode something here?

https://github.com/llvm/llvm-project/pull/98330