Create new library 'libc++experimental.a' for packaging TS symbols.
Summary:
Out-of-line symbols for <experimental/...> headers are not ABI or API stable and cannot live in the 'libc++.dylib'. Currently they have nowhere to live. I would like to add a new library target `libc++experimental.a` to fix this.
Previously I had suggested different libraries for different TS's (`libc++filesystem.a`, 'libc++LFTS.a`, ect). I no longer think this is the right approach.
Instead `c++experimental` will hold *all* TS implementations as a single monolithic library. I see two main benefits to this:
1. Users only have to know about and manually link one library.
2. It makes it easy to implement TS's with one or two out-of-line symbols. (Ex. PMRs)
`c++experimental` provides NO ABI compatibility. Symbols can freely be added/removed/changed without concern for ABI stability.
I will add documentation for this after landing this patch (but before adding anything to it).
`c++experimental` only builds as a static library. By default CMake will build/test this library but will *NOT* install it.
This patch adds the CMake and LIT logic needed to build/test the new library. Once this lands I plan on using it to implement parts of `<experimental/memory_resource>`.
Reviewers: mclow.lists
Subscribers: cfe-commits, theraven, krememek, dexonsmith, bcraig, beanz, danalbert
Differential Revision: http://reviews.llvm.org/D19856
llvm-svn: 268443
diff --git a/libcxx/CMakeLists.txt b/libcxx/CMakeLists.txt
index b21e295..abb1ffd 100644
--- a/libcxx/CMakeLists.txt
+++ b/libcxx/CMakeLists.txt
@@ -52,7 +52,7 @@
# Basic options ---------------------------------------------------------------
option(LIBCXX_ENABLE_ASSERTIONS "Enable assertions independent of build mode." ON)
option(LIBCXX_ENABLE_SHARED "Build libc++ as a shared library." ON)
-
+option(LIBCXX_ENABLE_EXPERIMENTAL_LIBRARY "Build libc++experimental.a" ON)
option(LIBCXX_INCLUDE_TESTS "Build the libc++ tests." ${LLVM_INCLUDE_TESTS})
option(LIBCXX_INCLUDE_DOCS "Build the libc++ documentation." ${LLVM_INCLUDE_DOCS})
set(LIBCXX_LIBDIR_SUFFIX "${LLVM_LIBDIR_SUFFIX}" CACHE STRING
@@ -60,6 +60,7 @@
option(LIBCXX_INSTALL_HEADERS "Install the libc++ headers." ON)
option(LIBCXX_INSTALL_LIBRARY "Install the libc++ library." ON)
option(LIBCXX_INSTALL_SUPPORT_HEADERS "Install libc++ support headers." ON)
+option(LIBCXX_INSTALL_EXPERIMENTAL_LIBRARY "Install libc++experimental.a" OFF)
set(LIBCXX_ABI_VERSION 1 CACHE STRING "ABI version of libc++.")
option(LIBCXX_ABI_UNSTABLE "Unstable ABI of libc++." OFF)
