[Arch Linux] R_X86_64_PC32 against symbol `memcpy@@GLIBC_2.14' can not be used

[Rosalie241]

clang version:

clang version 7.0.0 (tags/RELEASE_700/final)
Target: x86_64-pc-linux-gnu
Thread model: posix
InstalledDir: /usr/bin

output:
https://gist.github.com/tim241/3488247796c9bf9f0bc357d28f8a74c1

I've already tried to append -fPIC to the clang flags, no luck, same error.

[MichalStrehovsky]

I don't have Arch Linux around to try, I'm guessing this is coming from this line:

corert/src/ILCompiler.Compiler/src/Compiler/JitHelper.cs

Line 102 in 635cf21

mangledName = "memcpy"; // TODO: Null reference handling

Can you try changing the memcpy string to e.g. RhNewArray just to see if the linker error goes away? It's not the right fix, but if it does go away, I know how to fix it.

[Rosalie241]

@MichalStrehovsky when I try that, the error changes:

  /usr/sbin/ld: /builds/tim241/corert-bin/corert/tests/src/Simple/Generics/obj/Debug/x64/native/Generics.o: relocation R_X86_64_PC32 against symbol `fabs@@GLIBC_2.2.5' can not be used when making a PIE object; recompile with -fPIC

output:
https://gist.github.com/tim241/f134b841776fea4c3f0f0f8ab5e5a190

[MichalStrehovsky]

Interesting. It seems JitHelpers are not special relocation types after all.

Another guess is that the linker is trying to link agains GLIBC dynamically on Arch, instead of statically like we do elsewhere. Would that be a possibility?

[Rosalie241]

@MichalStrehovsky I have no idea, that'd be weird though?

[Rosalie241]

I've tried adding -static-libgcc -static-libstdc++ to the flags, however I still have the same issue.

  Generating native code
clang-7 : warning : argument unused during compilation: '-static-libstdc++' [-Wunused-command-line-argument] [/builds/tim241/corert-bin/corert/tests/src/Simple/Generics/Generics.csproj]
  /usr/sbin/ld: /builds/tim241/corert-bin/corert/tests/src/Simple/Generics/obj/Debug/x64/native/Generics.o: relocation R_X86_64_PC32 against symbol `memcpy@@GLIBC_2.14' can not be used when making a PIE object; recompile with -fPIC
  /usr/sbin/ld: final link failed: bad value

output:
https://gist.github.com/tim241/a9b1ebf5092535fa32c3bdc04eb82a3c

And here's the output when adding -static-libgcc -static-libstdc++ -v to the clang flags:
https://gist.github.com/tim241/aa6e31b2a1dfc7216e77905b308f578f

[jkotas]

This is same problem as #4988 . I think it is a bug in the object writer component - we are producing bad relocs on Unix.

[Rosalie241]

@jkotas okay, thank you 👍

I'll close this issue then!