Make libc++'s versioning namespace customizable
Summary:
This patch makes the versioning namespace libc++ uses customizable by the user using `-DLIBCXX_ABI_NAMESPACE=__foo`.
This allows users to build custom versions of libc++ which can be linked into binaries with other libc++ versions without causing symbol conflicts or ODR issues.
Reviewers: mclow.lists, ldionne
Reviewed By: ldionne
Subscribers: kristina, smeenai, mgorny, phosek, libcxx-commits
Differential Revision: https://reviews.llvm.org/D53879
git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@345657 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/include/__config b/include/__config
index f21cfba..b9295bf 100644
--- a/include/__config
+++ b/include/__config
@@ -119,7 +119,9 @@
#define _LIBCPP_CONCAT1(_LIBCPP_X,_LIBCPP_Y) _LIBCPP_X##_LIBCPP_Y
#define _LIBCPP_CONCAT(_LIBCPP_X,_LIBCPP_Y) _LIBCPP_CONCAT1(_LIBCPP_X,_LIBCPP_Y)
-#define _LIBCPP_NAMESPACE _LIBCPP_CONCAT(__,_LIBCPP_ABI_VERSION)
+#ifndef _LIBCPP_ABI_NAMESPACE
+# define _LIBCPP_ABI_NAMESPACE _LIBCPP_CONCAT(__,_LIBCPP_ABI_VERSION)
+#endif
#if __cplusplus < 201103L
#define _LIBCPP_CXX03_LANG
@@ -791,9 +793,9 @@
#define _LIBCPP_INLINE_VISIBILITY _LIBCPP_HIDE_FROM_ABI
// Inline namespaces are available in Clang/GCC/MSVC regardless of C++ dialect.
-#define _LIBCPP_BEGIN_NAMESPACE_STD namespace std { inline namespace _LIBCPP_NAMESPACE {
+#define _LIBCPP_BEGIN_NAMESPACE_STD namespace std { inline namespace _LIBCPP_ABI_NAMESPACE {
#define _LIBCPP_END_NAMESPACE_STD } }
-#define _VSTD std::_LIBCPP_NAMESPACE
+#define _VSTD std::_LIBCPP_ABI_NAMESPACE
_LIBCPP_BEGIN_NAMESPACE_STD _LIBCPP_END_NAMESPACE_STD
#if _LIBCPP_STD_VER >= 17
diff --git a/include/__config_site.in b/include/__config_site.in
index 7c7c226..580a6aa 100644
--- a/include/__config_site.in
+++ b/include/__config_site.in
@@ -28,6 +28,7 @@
#cmakedefine _LIBCPP_HAS_THREAD_LIBRARY_EXTERNAL
#cmakedefine _LIBCPP_DISABLE_VISIBILITY_ANNOTATIONS
#cmakedefine _LIBCPP_NO_VCRUNTIME
+#cmakedefine _LIBCPP_ABI_NAMESPACE @_LIBCPP_ABI_NAMESPACE@
@_LIBCPP_ABI_DEFINES@