Question
I tried compiling llvm15 on Ubuntu with AArch64 architecture. However, I encountered the following problems:
1. /usr/bin/ld: cannot find -lgcc_s, some of the errors are as follows:
[build] [73/4456 0% :: 1.026] Linking CXX static library lib/clang/15.0.1/lib/aarch64-unknown-linux-gnu/libclang_rt.fuzzer_no_main.a
[build] FAILED: lib/clang/15.0.1/lib/aarch64-unknown-linux-gnu/libclang_rt.fuzzer_no_main.a
[build] : && /usr/bin/cmake -E remove lib/clang/15.0.1/lib/aarch64-unknown-linux- ........
[build] /usr/bin/ld: cannot find -lgcc_s
[build] /usr/bin/ld: cannot find -lgcc_s
[build] clang: error: linker command failed with exit code 1 (use -v to see invocation)
[build] [73/4456 0% :: 1.261] Linking CXX shared library lib/clang/15.0.1/lib/aarch64-unknown-linux-gnu/libclang_rt.asan.so
[build] [73/4456 0% :: 1.322] Linking CXX static library lib/clang/15.0.1/lib/aarch64-unknown-linux-gnu/libclang_rt.fuzzer_interceptors.a
[build] FAILED: lib/clang/15.0.1/lib/aarch64-unknown-linux-gnu/libclang_rt.fuzzer_interceptors.a
[build] : && /usr/bin/cmake -E remove lib/clang/15.0.1/lib/aarch64-unknown-linux-gnu/libclang_rt.fuzzer_interceptors.a && /usr/bin/ar Dqc lib/clang/15.0.1/lib/
......
2. Modify the CMakeLists .txt
I tried adding something like the following to the CMakeLists .txt llvm, but configure didn’t work.
link_directories("/usr/lib/gcc/aarch64-linux-gnu/9/" "/usr/lib/aarch64-linux-gnu/")
link_libraries("/usr/lib/gcc/aarch64-linux-gnu/9/libgcc_s.so")
The same problem in 1 will appear.
Maybe there is a problem with what I added, and the specific subproject is configured like this. I took a screenshot below.
add_compiler_rt_object_libraries(RTfuzzer_interceptors
OS ${FUZZER_SUPPORTED_OS}
ARCHS ${FUZZER_SUPPORTED_ARCH}
SOURCES FuzzerInterceptors.cpp
CFLAGS ${LIBFUZZER_CFLAGS}
DEPS ${LIBFUZZER_DEPS})
# Tries to add an "object library" target for a given list of OSs and/or
# architectures with name "<name>.<arch>" for non-Darwin platforms if
# architecture can be targeted, and "<name>.<os>" for Darwin platforms.
# add_compiler_rt_object_libraries(<name>
# OS <os names>
# ARCHS <architectures>
# SOURCES <source files>
# CFLAGS <compile flags>
# DEFS <compile definitions>
# DEPS <dependencies>
# ADDITIONAL_HEADERS <header files>)
function(add_compiler_rt_object_libraries name)
cmake_parse_arguments(LIB "" "" "OS;ARCHS;SOURCES;CFLAGS;DEFS;DEPS;ADDITIONAL_HEADERS"
${ARGN})
set(libnames)
if(APPLE)
foreach(os ${LIB_OS})
set(libname "${name}.${os}")
set(libnames ${libnames} ${libname})
set(extra_cflags_${libname} ${DARWIN_${os}_CFLAGS})
list_intersect(LIB_ARCHS_${libname} DARWIN_${os}_ARCHS LIB_ARCHS)
endforeach()
else()
foreach(arch ${LIB_ARCHS})
set(libname "${name}.${arch}")
set(libnames ${libnames} ${libname})
set(extra_cflags_${libname} ${TARGET_${arch}_CFLAGS})
if(NOT CAN_TARGET_${arch})
message(FATAL_ERROR "Architecture ${arch} can't be targeted")
return()
endif()
endforeach()
endif()
# Add headers to LIB_SOURCES for IDEs
compiler_rt_process_sources(LIB_SOURCES
${LIB_SOURCES}
ADDITIONAL_HEADERS
${LIB_ADDITIONAL_HEADERS}
)
foreach(libname ${libnames})
add_library(${libname} OBJECT ${LIB_SOURCES})
if(LIB_DEPS)
add_dependencies(${libname} ${LIB_DEPS})
endif()
# Strip out -msse3 if this isn't macOS.
set(target_flags ${LIB_CFLAGS})
if(APPLE AND NOT "${libname}" MATCHES ".*\.osx.*")
list(REMOVE_ITEM target_flags "-msse3")
endif()
# Build the macOS sanitizers with Mac Catalyst support.
if (APPLE AND
"${COMPILER_RT_ENABLE_MACCATALYST}" AND
"${libname}" MATCHES ".*\.osx.*")
foreach(arch ${LIB_ARCHS_${libname}})
list(APPEND target_flags
"SHELL:-target ${arch}-apple-macos${DARWIN_osx_MIN_VER} -darwin-target-variant ${arch}-apple-ios13.1-macabi")
endforeach()
endif()
set_target_compile_flags(${libname}
${extra_cflags_${libname}} ${target_flags})
set_property(TARGET ${libname} APPEND PROPERTY
COMPILE_DEFINITIONS ${LIB_DEFS})
set_target_properties(${libname} PROPERTIES FOLDER "Compiler-RT Libraries")
if(APPLE)
set_target_properties(${libname} PROPERTIES
OSX_ARCHITECTURES "${LIB_ARCHS_${libname}}")
endif()
endforeach()
endfunction()
3. Modify LD configuration - no permission
After a Google search, I found that I can modify the configuration file of LD, but the user I use does not have permission to modify the changed file and cannot execute sudo.
$ cat /etc/ld.so.conf.d/aarch64-linux-gnu.conf
# Multiarch support
/usr/local/lib/aarch64-linux-gnu
/lib/aarch64-linux-gnu
/usr/lib/aarch64-linux-gnu
4. Modify the environment variables for the current user
I tried to add libgcc_s directory where .so is located to my current user’s LD_LIBRARY_PATH, and I still got an error in 1 when compiling.
I need help!
Is there any other way to enable the ld linker to find ‘libgcc_s.so’ when I can’t use sudo, yes, when compiling llvm via cmake? Or do I have a problem with the above workaround?