echo 'int foo;' | gcc -Wl,--no-define-common -shared -o foo.so -x c - /usr/bin/ld: BFD (GNU Binutils for Debian) 2.29 internal error, aborting at ../../bfd/elflink.c:9438 in elf_link_convert_common_type /usr/bin/ld: Please report this bug.
There is no testcase for --no-define-common. Linker manual says: '--no-define-common' This option inhibits the assignment of addresses to common symbols. The script command 'INHIBIT_COMMON_ALLOCATION' has the same effect. *Note Miscellaneous Commands::. The '--no-define-common' option allows decoupling the decision to assign addresses to Common symbols from the choice of the output file type; otherwise a non-Relocatable output type forces assigning addresses to Common symbols. Using '--no-define-common' allows Common symbols that are referenced from a shared library to be assigned addresses only in the main program. This eliminates the unused duplicate space in the shared library, and also prevents any possible confusion over resolving to the wrong duplicate when there are many dynamic modules with specialized search paths for runtime symbol resolution. It is unclear if common symbol should be treated as undefined in this case. Also is this option only allowed for building shared library?
Well I tried the flag to see if it would convince ld to preserve STT_COMMON in executables or shared libs, as the ELF specification says it is supposed to.
A patch is posted at https://sourceware.org/ml/binutils/2017-08/msg00047.html
The master branch has been updated by H.J. Lu <hjl@sourceware.org>: https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;h=a4819f54c0006554179631189131080be859eefb commit a4819f54c0006554179631189131080be859eefb Author: H.J. Lu <hjl.tools@gmail.com> Date: Sun Aug 6 08:18:53 2017 -0700 Treat common symbol as undefined for --no-define-common When --no-define-common is used to build shared library, treat common symbol as undefined so that common symbols that are referenced from a shared library to be assigned addresses only in the main program. This eliminates the unused duplicate space in the shared library, and also prevents any possible confusion over resolving to the wrong duplicate when there are many dynamic modules with specialized search paths for runtime symbol resolution. --no-define-common is only allowed when building a shared library. bfd/ PR ld/21903: * elflink.c (elf_link_add_object_symbols): Treat common symbol as undefined for --no-define-common. include/ PR ld/21903: * bfdlink.h (bfd_link_info): Add inhibit_common_definition. ld/ PR ld/21903: * ld.h (command_line): Remove inhibit_common_definition. * ldgram.y: Replace command_line.inhibit_common_definition with link_info.inhibit_common_definition. * ldlang.c (lang_common): Likewise. * lexsup.c (parse_args): Likewise. * ldmain.c (main): Only allow --no-define-common with -shared. * testsuite/ld-elf/pr21903.s: New file. * testsuite/ld-elf/pr21903a.d: Likewise. * testsuite/ld-elf/pr21903b.d: Likewise. * testsuite/ld-elf/pr21903c.d: Likewise. * testsuite/ld-elf/pr21903d.d: Likewise. * testsuite/ld-elf/pr21903e.d: Likewise.
Fixed for 2.30.
The master branch has been updated by H.J. Lu <hjl@sourceware.org>: https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;h=49263c56bbc622d5a42cfd37b4f5fb6863cd7d24 commit 49263c56bbc622d5a42cfd37b4f5fb6863cd7d24 Author: H.J. Lu <hjl.tools@gmail.com> Date: Wed Aug 23 16:01:22 2017 -0700 Update PR ld/21903 tests for dejagnu 1.4.4 Add '\' before -- to workaround dejagnu 1.4.4 which complains: ERROR: bad switch "--no-define-common may not be used without -shared":... * testsuite/ld-elf/pr21903c.d: Add '\' before --. * testsuite/ld-elf/pr21903d.d: Likewise. * testsuite/ld-elf/pr21903e.d: Likewise.