[llvm-dev] Compilation issue "unsupported relocation on symbol" with clang 3.7.1

[via llvm-dev]

Thank you Peter, I will try to patch instead.

Cheers

November 27, 2017 3:12 PM, "Peter Smith" <peter.smith at linaro.org> wrote:

> A very recent change to compiler-rt https://reviews.llvm.org/D39700
> recently the unconditional branch for v6-m in some of the aeabi_
> functions, if you are able to use compiler-rt from trunk or alter the
> compiler-rt source yourself you may be able to work around the problem
> without changing versions of llvm.
> 
> I'm not sure what to recommend otherwise, you may be able to turn off
> the integrated assembler and use arm-non-eabi-as for the files with
> unconditional branches, but I couldn't guarantee that would wouldn't
> result in other problems.
> 
> Peter
> 
> On 27 November 2017 at 11:02, <shiftag at nanotek.info> wrote:
> 
>> November 27, 2017 2:43 PM, "Peter Smith" <peter.smith at linaro.org> wrote:
>> 
>>> My best guess is that this is PR30279
>>> https://bugs.llvm.org/show_bug.cgi?id=30279 which was fixed in r280651
>>> in September 2016. Can you try again with a version of clang/llvm from
>>> after that point? Some versions of aeabi_memcpy.S contain an
>>> unconditional branch to memcpy (a branch out of section that can't be
>>> resolved at assembly time). The v6m unconditional branch has a very
>>> short range and earlier versions of llvm did not support the
>>> relocation.
>>> 
>>> Hope this helps
>> 
>> Hi Peter,
>> 
>> Thank you for your answer. I saw that pages before but I didn't find any
>> information about how to fix this. And unfortunately, I can't use a different
>> version of clang/llvm.
>> 
>> Thanks
>> 
>>> On 26 November 2017 at 12:09, via llvm-dev <llvm-dev at lists.llvm.org> wrote:
>> 
>> Hi List,
>> 
>> I'm trying to build llvm-5.0.0 with clang-3.7.1 on ARM (native building). At
>> some point I have the following issue :
>> 
>> ----
>> 
>> [1588/5024] Building C object
>> projects/compiler-rt/lib/builtins/CMakeFiles/clang_rt.builtins-arm.dir/cpu_model.c.o
>> ../projects/compiler-rt/lib/builtins/cpu_model.c:596:7: warning: ISO C
>> requires a translation unit to contain at least one declaration
>> [-Wempty-translation-unit]
>> #endif
>> ^
>> 1 warning generated.
>> [1786/5024] Building C object
>> projects/compiler-rt/lib/builtins/CMakeFiles/clang_rt.builtins-armv6m.dir/cpu_model.c.o
>> ../projects/compiler-rt/lib/builtins/cpu_model.c:596:7: warning: ISO C
>> requires a translation unit to contain at least one declaration
>> [-Wempty-translation-unit]
>> #endif
>> ^
>> 1 warning generated.
>> [1915/5024] Building ASM object
>> projects/compiler-rt/lib/built...s/CMakeFiles/clang_rt.builtins-armv6m.dir/arm/aeabi_memcmp.S.o
>> FAILED:
>> projects/compiler-rt/lib/builtins/CMakeFiles/clang_rt.builtins-armv6m.dir/arm/aeabi_memcmp.S.o
>> /usr/bin/clang -DLLVM_BUILD_GLOBAL_ISEL -D_FILE_OFFSET_BITS=64 -D_GNU_SOURCE
>> -D_LARGEFILE_SOURCE -D__STDC_CONSTANT_MACROS -D__STDC_FORMAT_MACROS
>> -D__STDC_LIMIT_MACROS -Iprojects/compiler-rt/lib/builtins
>> -I../projects/compiler-rt/lib/builtins -Iinclude -I../include -fPIC -O3
>> -DNDEBUG -march=armv6m -mfloat-abi=soft -fno-lto -MD -MT
>> projects/compiler-rt/lib/builtins/CMakeFiles/clang_rt.builtins-armv6m.dir/arm/aeabi_memcmp.S.o
>> -MF
>> projects/compiler-rt/lib/builtins/CMakeFiles/clang_rt.builtins-armv6m.dir/arm/aeabi_memcmp.S.o.d
>> -o
>> projects/compiler-rt/lib/builtins/CMakeFiles/clang_rt.builtins-armv6m.dir/arm/aeabi_memcmp.S.o
>> -c ../projects/compiler-rt/lib/builtins/arm/aeabi_memcmp.S
>> clang -cc1as: fatal error: error in backend: unsupported relocation on
>> symbol
>> [1917/5024] Building ASM object
>> projects/compiler-rt/lib/built.../CMakeFiles/clang_rt.builtins-armv6m.dir/arm/aeabi_memmove.S.o
>> FAILED:
>> projects/compiler-rt/lib/builtins/CMakeFiles/clang_rt.builtins-armv6m.dir/arm/aeabi_memmove.S.o
>> /usr/bin/clang -DLLVM_BUILD_GLOBAL_ISEL -D_FILE_OFFSET_BITS=64 -D_GNU_SOURCE
>> -D_LARGEFILE_SOURCE -D__STDC_CONSTANT_MACROS -D__STDC_FORMAT_MACROS
>> -D__STDC_LIMIT_MACROS -Iprojects/compiler-rt/lib/builtins
>> -I../projects/compiler-rt/lib/builtins -Iinclude -I../include -fPIC -O3
>> -DNDEBUG -march=armv6m -mfloat-abi=soft -fno-lto -MD -MT
>> projects/compiler-rt/lib/builtins/CMakeFiles/clang_rt.builtins-armv6m.dir/arm/aeabi_memmove.S.o
>> -MF
>> projects/compiler-rt/lib/builtins/CMakeFiles/clang_rt.builtins-armv6m.dir/arm/aeabi_memmove.S.o.d
>> -o
>> projects/compiler-rt/lib/builtins/CMakeFiles/clang_rt.builtins----armv6m.dir/arm/aeabi_memmove.S.o
>> -c ../projects/compiler-rt/lib/builtins/arm/aeabi_memmove.S
>> clang -cc1as: fatal error: error in backend: unsupported relocation on
>> symbol
>> [1918/5024] Building ASM object
>> projects/compiler-rt/lib/built...s/CMakeFiles/clang_rt.builtins-armv6m.dir/arm/aeabi_memcpy.S.o
>> FAILED:
>> projects/compiler-rt/lib/builtins/CMakeFiles/clang_rt.builtins-armv6m.dir/arm/aeabi_memcpy.S.o
>> /usr/bin/clang -DLLVM_BUILD_GLOBAL_ISEL -D_FILE_OFFSET_BITS=64 -D_GNU_SOURCE
>> -D_LARGEFILE_SOURCE -D__STDC_CONSTANT_MACROS -D__STDC_FORMAT_MACROS
>> -D__STDC_LIMIT_MACROS -Iprojects/compiler-rt/lib/builtins
>> -I../projects/compiler-rt/lib/builtins -Iinclude -I../include -fPIC -O3
>> -DNDEBUG -march=armv6m -mfloat-abi=soft -fno-lto -MD -MT
>> projects/compiler-rt/lib/builtins/CMakeFiles/clang_rt.builtins-armv6m.dir/arm/aeabi_memcpy.S.o
>> -MF
>> projects/compiler-rt/lib/builtins/CMakeFiles/clang_rt.builtins-armv6m.dir/arm/aeabi_memcpy.S.o.d
>> -o
>> projects/compiler-rt/lib/builtins/CMakeFiles/clang_rt.builtins-armv6m.dir/arm/aeabi_memcpy.S.o
>> -c ../projects/compiler-rt/lib/builtins/arm/aeabi_memcpy.S
>> clang -cc1as: fatal error: error in backend: unsupported relocation on
>> symbol
>> [1920/5024] Building CXX object
>> lib/Target/ARM/MCTargetDesc/CMakeFiles/LLVMARMDesc.dir/ARMMCTargetDesc.cpp.o
>> ninja: build stopped: subcommand failed.
>> 
>> ----
>> 
>> Relevant stuff:
>> clang -cc1as: fatal error: error in backend: unsupported relocation on
>> symbol
>> 
>> Well, I don't know how to fix that. Any ideas ?
>> 
>> Let me know if you need further info.
>> 
>> _______________________________________________
>> LLVM Developers mailing list
>> llvm-dev at lists.llvm.org
>> http://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-dev