From 976073794edf83b5e25c5c3bc285a1c2505bac9e Mon Sep 17 00:00:00 2001
From: Louis Dionne <ldionne@apple.com>
Date: Mon, 25 Mar 2019 14:56:29 +0000
Subject: [PATCH] [libc++][CMake] Allow merging libc++abi.a into libc++ even on
 Apple platforms

Summary:
I can't see a good reason to disallow this, even though it isn't the
standard way we build libc++ for Apple platforms.

Making this work on Apple platforms requires using different flags for
--whole-archive and removing the -D flag when running `ar` to merge
archives because that flag isn't supported by the `ar` shipped on Apple
platforms. This shouldn't be an issue since the -D option appears to be
enabled by default in GNU `ar`.

Reviewers: phosek, EricWF, serge-sans-paille

Subscribers: mgorny, christof, jkorous, dexonsmith, libcxx-commits

Differential Revision: https://reviews.llvm.org/D59513

llvm-svn: 356903
---
 libcxx/CMakeLists.txt          |  8 ++------
 libcxx/lib/CMakeLists.txt      | 13 +++++++++----
 libcxx/utils/merge_archives.py |  2 +-
 3 files changed, 12 insertions(+), 11 deletions(-)

diff --git a/libcxx/CMakeLists.txt b/libcxx/CMakeLists.txt
index 389d36f..9658fe4 100644
--- a/libcxx/CMakeLists.txt
+++ b/libcxx/CMakeLists.txt
@@ -359,13 +359,9 @@ elseif(LIBCXX_BUILD_32_BITS)
   message(FATAL_ERROR "LIBCXX_BUILD_32_BITS=ON is not supported on this platform.")
 endif()
 
-# Check that this option is not enabled on Apple and emit a usage warning.
+# Warn users that LIBCXX_ENABLE_STATIC_ABI_LIBRARY is an experimental option.
 if (LIBCXX_ENABLE_STATIC_ABI_LIBRARY)
-  if (APPLE)
-    message(FATAL_ERROR "LIBCXX_ENABLE_STATIC_ABI_LIBRARY is not supported on OS X")
-  else()
-    message(WARNING "LIBCXX_ENABLE_STATIC_ABI_LIBRARY is an experimental option")
-  endif()
+  message(WARNING "LIBCXX_ENABLE_STATIC_ABI_LIBRARY is an experimental option")
   if (LIBCXX_ENABLE_STATIC AND NOT PYTHONINTERP_FOUND)
     message(FATAL_ERROR "LIBCXX_ENABLE_STATIC_ABI_LIBRARY requires python but it was not found.")
   endif()
diff --git a/libcxx/lib/CMakeLists.txt b/libcxx/lib/CMakeLists.txt
index 4397189..50b7e28 100644
--- a/libcxx/lib/CMakeLists.txt
+++ b/libcxx/lib/CMakeLists.txt
@@ -52,14 +52,19 @@ endif()
 add_library_flags_if(LIBCXX_COVERAGE_LIBRARY "${LIBCXX_COVERAGE_LIBRARY}")
 
 if (APPLE AND (LIBCXX_CXX_ABI_LIBNAME STREQUAL "libcxxabi" OR
-               LIBCXX_CXX_ABI_LIBNAME STREQUAL "default"))
+               LIBCXX_CXX_ABI_LIBNAME STREQUAL "default")
+          AND NOT DEFINED LIBCXX_OSX_REEXPORT_LIBCXXABI_SYMBOLS)
   set(LIBCXX_OSX_REEXPORT_LIBCXXABI_SYMBOLS ON)
 endif()
 
 if (LIBCXX_STATICALLY_LINK_ABI_IN_SHARED_LIBRARY)
-  add_library_flags("-Wl,--whole-archive" "-Wl,-Bstatic")
-  add_library_flags("${LIBCXX_CXX_ABI_LIBRARY}")
-  add_library_flags("-Wl,-Bdynamic" "-Wl,--no-whole-archive")
+  if (APPLE)
+    add_library_flags("-Wl,-force_load" "${LIBCXX_CXX_ABI_LIBRARY}")
+  else()
+    add_library_flags("-Wl,--whole-archive" "-Wl,-Bstatic")
+    add_library_flags("${LIBCXX_CXX_ABI_LIBRARY}")
+    add_library_flags("-Wl,-Bdynamic" "-Wl,--no-whole-archive")
+  endif()
 elseif (LIBCXX_OSX_REEXPORT_LIBCXXABI_SYMBOLS)
   add_library_flags("${LIBCXX_CXX_ABI_LIBRARY}")
 else ()
diff --git a/libcxx/utils/merge_archives.py b/libcxx/utils/merge_archives.py
index e57afab..75d7a54 100755
--- a/libcxx/utils/merge_archives.py
+++ b/libcxx/utils/merge_archives.py
@@ -127,7 +127,7 @@ def main():
         out = execute_command_verbose([ar_exe, 't', arc])
         files.extend(out.splitlines())
 
-    execute_command_verbose([ar_exe, 'rcsD', args.output] + files,
+    execute_command_verbose([ar_exe, 'rcs', args.output] + files,
                             cwd=temp_directory_root, verbose=args.verbose)
 
 
-- 
2.7.4