From fe13c13cc236aebe042b58f1e7fa9f6712e037b9 Mon Sep 17 00:00:00 2001
From: Eric Fiselier <eric@efcs.ca>
Date: Tue, 30 Oct 2018 21:44:53 +0000
Subject: 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

llvm-svn: 345657
---
 libcxx/docs/BuildingLibcxx.rst | 12 ++++++++++++
 1 file changed, 12 insertions(+)

(limited to 'libcxx/docs')

diff --git a/libcxx/docs/BuildingLibcxx.rst b/libcxx/docs/BuildingLibcxx.rst
index daf9229a0d0..66cfb7b21ea 100644
--- a/libcxx/docs/BuildingLibcxx.rst
+++ b/libcxx/docs/BuildingLibcxx.rst
@@ -360,6 +360,18 @@ The following options allow building libc++ for a different ABI version.
   Build the "unstable" ABI version of libc++. Includes all ABI changing features
   on top of the current stable version.
 
+.. option:: LIBCXX_ABI_NAMESPACE:STRING
+
+  **Default**: ``__n`` where ``n`` is the current ABI version.
+
+  This option defines the name of the inline ABI versioning namespace. It can be used for building
+  custom versions of libc++ with unique symbol names in order to prevent conflicts or ODR issues
+  with other libc++ versions.
+
+  .. warning::
+    When providing a custom namespace, it's the users responsibility to ensure the name won't cause
+    conflicts with other names defined by libc++, both now and in the future.
+
 .. option:: LIBCXX_ABI_DEFINES:STRING
 
   **Default**: ``""``
-- 
cgit v1.2.3