[libcxxabi] Fix arm build failer with libgcc

Both arm32 armv7/armv8 bots which do not use compiler-rt are failing to a linking issue: [100%] Built target cxxabi_static CMakeFiles/cxxabi_shared.dir/cxa_demangle.cpp.o: In function `(anonymous namespace)::itanium_demangle::OutputStream::writeUnsigned(unsigned long long, bool)': /home/buildslave/buildslave/libcxx-libcxxabi-libunwind-armv7-linux-noexceptions/llvm/projects/libcxxabi/src/demangle/Utility.h:55: undefined reference to `__aeabi_uldivmod' /home/buildslave/buildslave/libcxx-libcxxabi-libunwind-armv7-linux-noexceptions/llvm/projects/libcxxabi/src/demangle/Utility.h:56: undefined reference to `__aeabi_uldivmod' clang-6.0: error: linker command failed with exit code 1 (use -v to see invocation) It seems after r371273 OutputStream is used more extensively and is pulling OutputStream::writeUnsigned (which thus requires unsigned integer module). The straightfoward fix is to explicit link against libgcc if compiler-rt is not used. llvm-svn: 372921
YuriPlyakhin · Sep 25, 2019 · 6023cf2 · 6023cf2
1 parent 5e9cdee
commit 6023cf2
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Showing 2 changed files with 12 additions and 2 deletions.
diff --git a/libcxxabi/cmake/config-ix.cmake b/libcxxabi/cmake/config-ix.cmake
@@ -7,6 +7,7 @@ include(CheckCSourceCompiles)
 check_library_exists(c fopen "" LIBCXXABI_HAS_C_LIB)
 if (NOT LIBCXXABI_USE_COMPILER_RT)
   check_library_exists(gcc_s __gcc_personality_v0 "" LIBCXXABI_HAS_GCC_S_LIB)
+  check_library_exists(gcc __aeabi_uldivmod "" LIBCXXABI_HAS_GCC_LIB)
 endif ()
 
 # libc++abi is built with -nodefaultlibs, so we want all our checks to also
@@ -26,8 +27,13 @@ if (LIBCXXABI_HAS_NODEFAULTLIBS_FLAG)
     list(APPEND CMAKE_REQUIRED_FLAGS -rtlib=compiler-rt)
     find_compiler_rt_library(builtins LIBCXXABI_BUILTINS_LIBRARY)
     list(APPEND CMAKE_REQUIRED_LIBRARIES "${LIBCXXABI_BUILTINS_LIBRARY}")
-  elseif (LIBCXXABI_HAS_GCC_S_LIB)
-    list(APPEND CMAKE_REQUIRED_LIBRARIES gcc_s)
+  else ()
+    if (LIBCXXABI_HAS_GCC_S_LIB)
+      list(APPEND CMAKE_REQUIRED_LIBRARIES gcc_s)
+    endif ()
+    if (LIBCXXABI_HAS_GCC_LIB)
+      list(APPEND CMAKE_REQUIRED_LIBRARIES gcc)
+    endif ()
   endif ()
   if (MINGW)
     # Mingw64 requires quite a few "C" runtime libraries in order for basic

diff --git a/libcxxabi/src/CMakeLists.txt b/libcxxabi/src/CMakeLists.txt
@@ -91,6 +91,10 @@ if (MINGW)
   list(APPEND LIBCXXABI_LIBRARIES ${MINGW_LIBRARIES})
 endif()
 
+if (NOT LIBCXXABI_USE_COMPILER_RT)
+  add_library_flags_if(LIBCXXABI_HAS_GCC_LIB gcc)
+endif ()
+
 # Setup flags.
 add_link_flags_if_supported(-nodefaultlibs)