[libcxx] r272723 - Automatically detect export lists for OS X.

[Eric Fiselier via cfe-commits]

Author: ericwf
Date: Tue Jun 14 16:55:14 2016
New Revision: 272723

URL: http://llvm.org/viewvc/llvm-project?rev=272723&view=rev
Log:
Automatically detect export lists for OS X.

Summary:
Libc++ reexports symbols from the system libc++abi using -reexport_symbols_list. This can cause a linker failure if the list contains symbols not defined in the system libc++abi.
This patch attempts to detect the OS X version and use it to determine the correct symbol list. 

It's my understanding that `lib/libc++abi2.exp` should be used on 10.9 and greater. Otherwise 'lib/libc++abi.exp' should be used

This fixes PR25666 (https://llvm.org/bugs/show_bug.cgi?id=25666)

Reviewers: mclow.lists, bcraig, dexonsmith, EricWF

Subscribers: cfe-commits

Differential Revision: http://reviews.llvm.org/D20772

Modified:
    libcxx/trunk/lib/CMakeLists.txt

Modified: libcxx/trunk/lib/CMakeLists.txt
URL: http://llvm.org/viewvc/llvm-project/libcxx/trunk/lib/CMakeLists.txt?rev=272723&r1=272722&r2=272723&view=diff
==============================================================================
--- libcxx/trunk/lib/CMakeLists.txt (original)
+++ libcxx/trunk/lib/CMakeLists.txt Tue Jun 14 16:55:14 2016
@@ -88,7 +88,21 @@ add_link_flags_if_supported(-nodefaultli
 if ( APPLE AND (LIBCXX_CXX_ABI_LIBNAME STREQUAL "libcxxabi" OR
                 LIBCXX_CXX_ABI_LIBNAME STREQUAL "none"))
   if (NOT DEFINED LIBCXX_LIBCPPABI_VERSION)
-    set(LIBCXX_LIBCPPABI_VERSION "2")
+    set(LIBCXX_LIBCPPABI_VERSION "2") # Default value
+    execute_process(
+      COMMAND xcrun --show-sdk-version
+      OUTPUT_VARIABLE sdk_ver
+      RESULT_VARIABLE res
+      OUTPUT_STRIP_TRAILING_WHITESPACE)
+    if (res EQUAL 0)
+      message(STATUS "Found SDK version ${sdk_ver}")
+      string(REPLACE "10." "" sdk_ver "${sdk_ver}")
+      if (sdk_ver LESS 9)
+        set(LIBCXX_LIBCPPABI_VERSION "")
+      else()
+        set(LIBCXX_LIBCPPABI_VERSION "2")
+      endif()
+    endif()
   endif()
 
   if ( CMAKE_OSX_DEPLOYMENT_TARGET STREQUAL "10.6" )