[PATCH] D50344: [libc++] Enable aligned allocation based on feature test macro, irrespective of standard

[Louis Dionne via Phabricator via cfe-commits]

ldionne created this revision.
ldionne added a reviewer: vsapsai.
Herald added a reviewer: EricWF.
Herald added subscribers: cfe-commits, dexonsmith, christof.

The current code enables aligned allocation functions when compiling in C++17
and later. This is a problem because aligned allocation functions might not
be supported on the target platform, which leads to an error at link time.

Since r338934, Clang knows not to define __cpp_aligned_new when it's not
available on the target platform -- this commit takes advantage of that to
only use aligned allocation functions when they are available.


Repository:
  rCXX libc++

https://reviews.llvm.org/D50344

Files:
  libcxx/include/__config
  libcxx/include/new
  libcxx/test/libcxx/memory/aligned_allocation_macro.pass.cpp


Index: libcxx/test/libcxx/memory/aligned_allocation_macro.pass.cpp
===================================================================
--- /dev/null
+++ libcxx/test/libcxx/memory/aligned_allocation_macro.pass.cpp
@@ -0,0 +1,25 @@
+//===----------------------------------------------------------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is dual licensed under the MIT and the University of Illinois Open
+// Source Licenses. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+// UNSUPPORTED: c++98, c++03, c++11, c++14
+// XFAIL: with_system_cxx_lib=macosx10.12
+// XFAIL: with_system_cxx_lib=macosx10.11
+// XFAIL: with_system_cxx_lib=macosx10.10
+// XFAIL: with_system_cxx_lib=macosx10.9
+// XFAIL: with_system_cxx_lib=macosx10.8
+// XFAIL: with_system_cxx_lib=macosx10.7
+
+#include <new>
+
+
+#ifdef _LIBCPP_HAS_NO_ALIGNED_ALLOCATION
+#   error "libc++ should have aligned allocation in C++17 and up when targeting a platform that supports it"
+#endif
+
+int main() { }
Index: libcxx/include/new
===================================================================
--- libcxx/include/new
+++ libcxx/include/new
@@ -108,13 +108,6 @@
 # define _LIBCPP_HAS_NO_SIZED_DEALLOCATION
 #endif
 
-#if !defined(_LIBCPP_HAS_NO_ALIGNED_ALLOCATION) && \
-    (!(defined(_LIBCPP_BUILDING_LIBRARY) || _LIBCPP_STD_VER > 14 || \
-    (defined(__cpp_aligned_new) && __cpp_aligned_new >= 201606)))
-# define _LIBCPP_HAS_NO_ALIGNED_ALLOCATION
-#endif
-
-
 #if !__has_builtin(__builtin_operator_new) || \
    __has_builtin(__builtin_operator_new) < 201802L || \
    defined(_LIBCPP_HAS_NO_ALIGNED_ALLOCATION) || \
Index: libcxx/include/__config
===================================================================
--- libcxx/include/__config
+++ libcxx/include/__config
@@ -988,6 +988,11 @@
 #  endif
 #endif // defined(__APPLE__)
 
+#if !defined(_LIBCPP_HAS_NO_ALIGNED_ALLOCATION) && \
+    !defined(_LIBCPP_BUILDING_LIBRARY) && \
+    !defined(__cpp_aligned_new)
+#  define _LIBCPP_HAS_NO_ALIGNED_ALLOCATION
+#endif
 
 #if defined(__APPLE__) || defined(__FreeBSD__)
 #define _LIBCPP_HAS_DEFAULTRUNELOCALE


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