[libcxxabi] r286759 - [CMake] Fix libc++abi arm build w/o libunwind.

[Logan Chien via cfe-commits]

Author: logan
Date: Sun Nov 13 08:42:15 2016
New Revision: 286759

URL: http://llvm.org/viewvc/llvm-project?rev=286759&view=rev
Log:
[CMake] Fix libc++abi arm build w/o libunwind.

This commit fixes libc++abi build when LLVM unwinder (libunwind_llvm) is
not enabled.

This commit fixes the problem by removing "LLVM_NATIVE_ARCH MATCHES ARM"
from CMakeLists.txt so that LIBCXXABI_USE_LLVM_UNWINDER will only be
defined when LLVM unwinder is enabled.

We need LIBCXXABI_USE_LLVM_UNWINDER becase there is a subtle difference
between the unwinder from libgcc and the one from libunwind_llvm.  For
the unwinder from libgcc, we have to initialize register r12 with the
address of _Unwind_Control_Block; otherwise,
_Unwind_GetLanguageSpecificData() and _Unwind_GetRegionStart() won't
work properly.  Consequently, there is an extra _Unwind_SetGR() when
LLVM unwinder is disabled.  Check cxa_personality.cpp for details.

Modified:
    libcxxabi/trunk/CMakeLists.txt

Modified: libcxxabi/trunk/CMakeLists.txt
URL: http://llvm.org/viewvc/llvm-project/libcxxabi/trunk/CMakeLists.txt?rev=286759&r1=286758&r2=286759&view=diff
==============================================================================
--- libcxxabi/trunk/CMakeLists.txt (original)
+++ libcxxabi/trunk/CMakeLists.txt Sun Nov 13 08:42:15 2016
@@ -362,7 +362,7 @@ if (MSVC)
 endif()
 
 # Define LIBCXXABI_USE_LLVM_UNWINDER for conditional compilation.
-if (LIBCXXABI_USE_LLVM_UNWINDER OR LLVM_NATIVE_ARCH MATCHES ARM)
+if (LIBCXXABI_USE_LLVM_UNWINDER)
   add_definitions(-DLIBCXXABI_USE_LLVM_UNWINDER=1)
 endif()