remove duplicated code

Author: poor-circle

libcxx/include/__memory/align.h

@@ -20,12 +20,12 @@
 _LIBCPP_BEGIN_NAMESPACE_STD
 
 #ifdef _LIBCPP_ALIGN_DEFINE_LEGACY_INLINE_FUNCTIONS
-
-_LIBCPP_EXPORTED_FROM_ABI void* align(size_t __align, size_t __sz, void*& __ptr, size_t& __space);
-
+#  define _LIBCPP_ALIGN_ABI_VISIBILITY _LIBCPP_EXPORTED_FROM_ABI
 #else
+#  define _LIBCPP_ALIGN_ABI_VISIBILITY _LIBCPP_HIDE_FROM_ABI
+#endif // _LIBCPP_ALIGN_DEFINE_LEGACY_INLINE_FUNCTIONS
 
-inline _LIBCPP_HIDE_FROM_ABI void* align(size_t __align, size_t __sz, void*& __ptr, size_t& __space) {
+inline _LIBCPP_ALIGN_ABI_VISIBILITY void* align(size_t __align, size_t __sz, void*& __ptr, size_t& __space) {
   void* __r = nullptr;
   if (__sz <= __space) {
     char* __p1 = static_cast<char*>(__ptr);
@@ -40,7 +40,7 @@ inline _LIBCPP_HIDE_FROM_ABI void* align(size_t __align, size_t __sz, void*& __p
   return __r;
 }
 
-#endif // _LIBCPP_ALIGN_DEFINE_LEGACY_INLINE_FUNCTIONS
+#undef _LIBCPP_ALIGN_ABI_VISIBILITY
 
 _LIBCPP_END_NAMESPACE_STD
 

libcxx/src/memory.cpp

@@ -135,20 +135,8 @@ __sp_mut& __get_sp_mut(const void* p) {
 
 #if defined(_LIBCPP_ALIGN_DEFINE_LEGACY_INLINE_FUNCTIONS)
 
-void* align(size_t alignment, size_t size, void*& ptr, size_t& space) {
-  void* r = nullptr;
-  if (size <= space) {
-    char* p1 = static_cast<char*>(ptr);
-    char* p2 = reinterpret_cast<char*>(reinterpret_cast<uintptr_t>(p1 + (alignment - 1)) & -alignment);
-    size_t d = static_cast<size_t>(p2 - p1);
-    if (d <= space - size) {
-      r   = p2;
-      ptr = r;
-      space -= d;
-    }
-  }
-  return r;
-}
+constinit auto* __align__abi__keeper = align;
+
 #endif // _LIBCPP_ALIGN_DEFINE_LEGACY_INLINE_FUNCTIONS
 
 _LIBCPP_END_NAMESPACE_STD

libcxx/test/benchmarks/memory/align.bench.cpp

@@ -15,12 +15,11 @@
 
 static void BM_align(benchmark::State& state) {
   char buffer[1024];
-  char* data = buffer + 123;
-  std::size_t sz{1024 - 123};
-  void* p;
+  void* data = buffer + 123;
+  std::size_t sz{sizeof(buffer) - 123};
 
   for (auto _ : state) {
-    benchmark::DoNotOptimize(std::align(state.range(), state.range(), p, sz))
+    benchmark::DoNotOptimize(std::align(state.range(), state.range(), data, sz));
   }
 }
 BENCHMARK(BM_align)->Range(1, 256);