On Thu, Nov 5, 2020 at 3:37 AM Jozef Lawrynowicz <joze...@mittosystems.com> wrote: > > On Thu, Nov 05, 2020 at 06:21:21AM -0500, Hans-Peter Nilsson wrote: > > On Wed, 4 Nov 2020, H.J. Lu wrote: > > > .retain is ill-defined. For example, > > > > > > [hjl@gnu-cfl-2 gcc]$ cat /tmp/x.c > > > static int xyzzy __attribute__((__used__)); > > > [hjl@gnu-cfl-2 gcc]$ ./xgcc -B./ -S /tmp/x.c -fcommon > > > [hjl@gnu-cfl-2 gcc]$ cat x.s > > > .file "x.c" > > > .text > > > .retain xyzzy <<<<<<<<< What does it do? > > > .local xyzzy > > > .comm xyzzy,4,4 > > > .ident "GCC: (GNU) 11.0.0 20201103 (experimental)" > > > .section .note.GNU-stack,"",@progbits > > > [hjl@gnu-cfl-2 gcc]$ > > > > To answer that question: it's up to the assembler, but for ELF > > and SHF_GNU_RETAIN, it seems obvious it'd tell the assembler to > > set SHF_GNU_RETAIN for the section where the symbol ends up. > > We both know this isn't rocket science with binutils. > > Indeed, and my patch handles it trivially: > https://sourceware.org/pipermail/binutils/2020-November/113993.html > > +void > +obj_elf_retain (int arg ATTRIBUTE_UNUSED) > .... snip .... > + sym = get_sym_from_input_line_and_check (); > + symbol_get_obj (sym)->retain = 1; > > @@ -2624,6 +2704,9 @@ elf_frob_symbol (symbolS *symp, int *puntp) > } > } > > + if (symbol_get_obj (symp)->retain) > + elf_section_flags (S_GET_SEGMENT (symp)) |= SHF_GNU_RETAIN; > + > /* Double check weak symbols. */ > if (S_IS_WEAK (symp)) > { > > We could check that the symbol named in the .retain directive has > already been defined, however this isn't compatible with GCC > mark_decl_preserved handling, since mark_decl_preserved is called > emitted before the local symbols are defined in the assembly output > file. > > GAS should at least validate that the symbol named in the .retain > directive does end up as a symbol though. >
Don't add .retain. -- H.J.
