[CMake] Don't use -rtlib=compiler-rt with -nodefaultlibs.

Summary:
This switch only has an effect at link time. It changes the default
compiler support library to `compiler-rt`. With `-nodefaultlibs`, this
library won't get linked anyway; Clang actually warns about that.

Reviewers: mstorsjo, rnk

Subscribers: dberris, mgorny, christof, cfe-commits

Differential Revision: https://reviews.llvm.org/D51645

llvm-svn: 341404

diff --git a/libunwind/CMakeLists.txt b/libunwind/CMakeLists.txt
index d73c0dd..bab9e08 100644 (file)
--- a/libunwind/CMakeLists.txt
+++ b/libunwind/CMakeLists.txt
@@ -234,7 +234,7 @@ endif()
 # Configure compiler.
 include(config-ix)
 
-if (LIBUNWIND_USE_COMPILER_RT)
+if (LIBUNWIND_USE_COMPILER_RT AND NOT LIBUNWIND_HAS_NODEFAULTLIBS_FLAG)
   list(APPEND LIBUNWIND_LINK_FLAGS "-rtlib=compiler-rt")
 endif()
 

diff --git a/libunwind/cmake/config-ix.cmake b/libunwind/cmake/config-ix.cmake
index 2d4da64..f4f9ee8 100644 (file)
--- a/libunwind/cmake/config-ix.cmake
+++ b/libunwind/cmake/config-ix.cmake
@@ -23,7 +23,6 @@ if (LIBUNWIND_HAS_NODEFAULTLIBS_FLAG)
     list(APPEND CMAKE_REQUIRED_LIBRARIES c)
   endif ()
   if (LIBUNWIND_USE_COMPILER_RT)
-    list(APPEND CMAKE_REQUIRED_FLAGS -rtlib=compiler-rt)
     find_compiler_rt_library(builtins LIBUNWIND_BUILTINS_LIBRARY)
     list(APPEND CMAKE_REQUIRED_LIBRARIES "${LIBUNWIND_BUILTINS_LIBRARY}")
   elseif (LIBUNWIND_HAS_GCC_S_LIB)