Revert "[CMake][libunwind] Use -nodefaultlibs for CMake checks"

This reverts commit r299796.

git-svn-id: https://llvm.org/svn/llvm-project/libunwind/trunk@299798 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 2 insertions, 23 deletions

diff --git a/cmake/config-ix.cmake b/cmake/config-ix.cmake
index be12ed5..0b0bb5c 100644
--- a/cmake/config-ix.cmake
+++ b/cmake/config-ix.cmake
@@ -3,35 +3,13 @@ include(CheckCCompilerFlag)
 include(CheckCXXCompilerFlag)
 include(CheckLibraryExists)
 
-check_library_exists(c fopen "" LIBUNWIND_HAS_C_LIB)
-
-# libunwind is built with -nodefaultlibs, so we want all our checks to also
-# use this option, otherwise we may end up with an inconsistency between
-# the flags we think we require during configuration (if the checks are
-# performed without -nodefaultlibs) and the flags that are actually
-# required during compilation (which has the -nodefaultlibs). libc is
-# required for the link to go through. We remove sanitizers from the
-# configuration checks to avoid spurious link errors.
-check_c_compiler_flag(-nodefaultlibs LIBUNWIND_HAS_NODEFAULTLIBS_FLAG)
-if (LIBUNWIND_HAS_NODEFAULTLIBS_FLAG)
-  set(CMAKE_REQUIRED_FLAGS "${CMAKE_REQUIRED_FLAGS} -nodefaultlibs")
-  if (LIBUNWIND_HAS_C_LIB)
-    list(APPEND CMAKE_REQUIRED_LIBRARIES c)
-  endif ()
-  if (CMAKE_C_FLAGS MATCHES -fsanitize OR CMAKE_CXX_FLAGS MATCHES -fsanitize)
-    set(CMAKE_REQUIRED_FLAGS "${CMAKE_REQUIRED_FLAGS} -fno-sanitize=all")
-  endif ()
-  if (CMAKE_C_FLAGS MATCHES -fsanitize-coverage OR CMAKE_CXX_FLAGS MATCHES -fsanitize-coverage)
-    set(CMAKE_REQUIRED_FLAGS "${CMAKE_REQUIRED_FLAGS} -fno-sanitize-coverage=edge,trace-cmp,indirect-calls,8bit-counters")
-  endif ()
-endif ()
-
 # Check compiler flags
 check_c_compiler_flag(-funwind-tables         LIBUNWIND_HAS_FUNWIND_TABLES)
 check_cxx_compiler_flag(-fPIC                 LIBUNWIND_HAS_FPIC_FLAG)
 check_cxx_compiler_flag(-fno-exceptions       LIBUNWIND_HAS_NO_EXCEPTIONS_FLAG)
 check_cxx_compiler_flag(-fno-rtti             LIBUNWIND_HAS_NO_RTTI_FLAG)
 check_cxx_compiler_flag(-fstrict-aliasing     LIBUNWIND_HAS_FSTRICT_ALIASING_FLAG)
+check_cxx_compiler_flag(-nodefaultlibs        LIBUNWIND_HAS_NODEFAULTLIBS_FLAG)
 check_cxx_compiler_flag(-nostdinc++           LIBUNWIND_HAS_NOSTDINCXX_FLAG)
 check_cxx_compiler_flag(-Wall                 LIBUNWIND_HAS_WALL_FLAG)
 check_cxx_compiler_flag(-W                    LIBUNWIND_HAS_W_FLAG)
@@ -66,6 +44,7 @@ if(LIBUNWIND_HAS_STD_CXX11)
   set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -std=c++11")
 endif()
 
+check_library_exists(c fopen "" LIBUNWIND_HAS_C_LIB)
 check_library_exists(dl dladdr "" LIBUNWIND_HAS_DL_LIB)
 check_library_exists(pthread pthread_once "" LIBUNWIND_HAS_PTHREAD_LIB)