R_X86_64_64 relocation against symbol `__gxx_personality_v0' can not be used

[mrichtarsky]

Hi,

first, thanks for the great linker, which provides speedups I didn't deem possible on Linux x86 (I'm seeing factor 7 over gold).

I'm getting this error when linking a static library generated by ICC with other GCC binaries. Granted, it's a bit strange to do this on static library/object boundaries, but at least it works with gold. Is there something that rings a bell why this would not work? The files in the library were compiled with -fPIC.

mold: warning: libsse_icc.a(searchbv.cpp.o):(.gnu.linkonce.d.DW.ref.__gxx_personality_v0): R_X86_64_64 relocation against symbol `__gxx_personality_v0' can not be used; recompile with -fPIC

The message is thrown from input-sections.cc with the following context:

get_sym_type(): 3
get_output_type(): 0
action: DYNREL

Thanks and best regards,
Martin

[rui314]

Thank you for reporting the issue!

If you can share searchbv.cpp.o or any other object file mold was complaining to, can you attach that file here? I'd like to take a closer look.

[rui314]

.gnu.linkonce is a old feature for so-called vague linking, and that is now superseded by COMDAT. We can probably ignore that section generated by ICC because the duplicated symbol is surely provided by GCC-generated file.

Can you try this patch to see if this fixes your problem?

diff --git a/elf/input-files.cc b/elf/input-files.cc
index 43f18ff29..7eec55169 100644
--- a/elf/input-files.cc
+++ b/elf/input-files.cc
@@ -236,11 +236,12 @@ void ObjectFile<E>::initialize_sections(Context<E> &ctx) {
       }

       // Ignore these sections for compatibility with old glibc i386
       // CRT files.
       if (name == ".gnu.linkonce.t.__x86.get_pc_thunk.bx" ||
-          name == ".gnu.linkonce.t.__i686.get_pc_thunk.bx")
+          name == ".gnu.linkonce.t.__i686.get_pc_thunk.bx" ||
+          name == ".gnu.linkonce.d.DW.ref.__gxx_personality_v0")
         continue;

       if ((ctx.arg.strip_all || ctx.arg.strip_debug) &&
           is_debug_section(shdr, name))
         continue;

[mrichtarsky]

This fixes it, thanks!

[rui314]

For the record, can you tell me what your ICC's version is?

[mrichtarsky]

Version is Intel 19.1.3.20200925

[rui314]

Filed a bug to https://community.intel.com/t5/Intel-C-Compiler/ICC-uses-GNU-linkonce-instead-of-COMDAT-for-gxx-personality-v0/m-p/1353314#M39628