https://gcc.gnu.org/bugzilla/show_bug.cgi?id=81968
--- Comment #57 from ro at CeBiTec dot Uni-Bielefeld.DE <ro at CeBiTec dot
Uni-Bielefeld.DE> ---
> --- Comment #56 from rguenther at suse dot de <rguenther at suse dot de> ---
> On Wed, 10 Jan 2018, ro at CeBiTec dot Uni-Bielefeld.DE wrote:
[...]
> I can reproduce that with -ffat-lto-objects where indeed we somehow
> get confused when we should preserve only part of a SHT_GROUP given
> we don't "prune" groups. The question to me is why do we put
> both macro sections in a single group ... but that's probably
> an artifact on how things are supposed to work in the end...
> [I wonder if SHF_EXCLUDE works "properly" for group members when
> doing a non-LTO link]
>
> Anyway, this should be "easy" to fix with sth like
>
> else if (sh_type == SHT_GROUP)
> {
> /* Remap section indices in groups and remove removed members.
> */
> unsigned char *ent, *dst;
> for (dst = ent = buf + 4; ent < buf + length - 4; ent += 4)
> {
> unsigned shndx = type_functions->fetch_Elf_Word (ent);
> if (pfnret[shndx - 1] == -1)
> ;
> else
> {
> type_functions->set_Elf_Word (dst, sh_map[shndx]);
> dst += 4;
> }
> }
> /* Adjust the length. */
> length = dst - buf;
> }
>
> in the group handling.
>
> That fixes -ffat-lto-objects handling for me with the testcase.
> Will re-test with that.
[I'm continuing this with examples from a build using gas 2.29 instead
of as since things are easier to see there.]
While this fixed the error in the group section
Group Section: .group
Signature Symbol: wm4.0.b58ba986a79b71e96526231091292919
Members:
index flags / section
[0] [ COMDAT ]
[1] .debug_macro
COMDAT group section [ 1] `.group' [wm4.0.b58ba986a79b71e96526231091292919]
contains 1 sections:
[Index] Name
[ 7] .debug_macro
the link error (during ld -r) remains:
ld: fatal: relocation error: R_386_32: file /var/tmp//cco6lLmcdebugobjtem:
section [6].rel.debug_macro: symbol .debug_macro (section): symbol has been
discarded with discarded section: [7].debug_macro
Relocation Section: .rel.debug_macro
index type offset value section symbol
[0] R_386_32 0x3 0 .debug_macro .debug_line (section)
[1] R_386_32 0x8 0 .debug_macro .debug_macro (section)
We do have two .debug_macro sections and their corresponding reloc
sections here, as already in the input objects:
Section Header[6]: sh_name: .rel.debug_macro
sh_addr: 0 sh_flags: [ SHF_INFO_LINK ]
sh_size: 0x10 sh_type: [ SHT_REL ]
sh_offset: 0x324 sh_entsize: 0x8 (2 entries)
sh_link: 11 sh_info: 5
sh_addralign: 0x4
Section Header[8]: sh_name: .rel.debug_macro
sh_addr: 0 sh_flags: [ SHF_INFO_LINK ]
sh_size: 0xa50 sh_type: [ SHT_REL ]
sh_offset: 0xaf4 sh_entsize: 0x8 (330 entries)
sh_link: 11 sh_info: 7
sh_addralign: 0x4
Section Header[5]: sh_name: .debug_macro
sh_addr: 0 sh_flags: 0
sh_size: 0x11 sh_type: [ SHT_PROGBITS ]
sh_offset: 0x312 sh_entsize: 0
sh_link: 0 sh_info: 0
sh_addralign: 0x1
Section Header[7]: sh_name: .debug_macro
sh_addr: 0 sh_flags: [ SHF_GROUP ]
sh_size: 0x7c0 sh_type: [ SHT_PROGBITS ]
sh_offset: 0x334 sh_entsize: 0
sh_link: 0 sh_info: 0
sh_addralign: 0x1
Rainer
