Is there a way to unhide hidden-visibility symbols with GNU binutils?
binutils, c, gcc, visibility
Solution
`objcopy` doesn't seem to have this feature, but you can do it with the ELFkickers `rebind` tool:
rebind --visibility default file.o SYMBOLS...
This must be done on the original .o files. If you try to do it on the .so it'll be too late, because the hidden symbols will have been omitted from the `.dynsym` section.
Problem
I'm working on a script to make uClibc usable on an existing glibc-targetted gcc/binutils toolchain, and the one problem I'm left with is that `pthread_cancel` needs to `dlopen` `libgcc_s.so.1`. The version supplied with the host gcc is linked to depend on glibc, so I'm instead using `ld`'s `-u` option to pull in the needed symbols (and their dependencies) from `libgcc_eh.a` to make a replacement `libgcc_s.so.1`: ``` gcc -specs uclibc.specs -Wl,-u,_Unwind_Resume -Wl,-u,__gcc_personality_v0 \ -Wl,-u,_Unwind_ForcedUnwind -Wl,-u,_Unwind_GetCFA -shared -o libgcc_s.so.1 ``` In principle I would be done, but all the symbols in `libgcc_eh.a` have their visibility set to hidden, so in the output `.so` file, they all become local and don't get added to the `.dynsym` symbol table. I'm looking for a way to use binutils (perhaps `objcopy`? or a linker script?) on either the `.so` file or the original `.o` files in `libgcc_eh.a` to un-hide these symbols. Is this possible?