feat: placement new

Signed-off-by: Zone.N <[email protected]>

src/kernel/libcxx/include/sk_new

@@ -19,13 +19,13 @@
 
 #include <cstddef>
 
-void* operator new(size_t) noexcept;
+[[nodiscard]] void* operator new(size_t) noexcept;
 
-void* operator new[](size_t) noexcept;
+[[nodiscard]] void* operator new[](size_t) noexcept;
 
-void* operator new(size_t, size_t) noexcept;
+[[nodiscard]] void* operator new(size_t, size_t) noexcept;
 
-void* operator new[](size_t, size_t) noexcept;
+[[nodiscard]] void* operator new[](size_t, size_t) noexcept;
 
 void operator delete(void*);
 
@@ -35,4 +35,18 @@ void operator delete[](void*);
 
 void operator delete[](void*, size_t);
 
+// Default placement versions of operator new.
+[[nodiscard]] __always_inline void* operator new(std::size_t,
+                                                 void* p) noexcept {
+  return p;
+}
+[[nodiscard]] __always_inline void* operator new[](std::size_t,
+                                                   void* p) noexcept {
+  return p;
+}
+
+// Default placement versions of operator delete.
+__always_inline void operator delete(void*, void*) noexcept {}
+__always_inline void operator delete[](void*, void*) noexcept {}
+
 #endif /* SIMPLEKERNEL_SRC_KERNEL_LIBCXX_INCLUDE_SK_NEW_ */