[Bug lto/81968] [8 regression] early lto debug objects make Solaris ld SEGV

[rguenther at suse dot de]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=81968

--- Comment #43 from rguenther at suse dot de <rguenther at suse dot de> ---
On Tue, 2 Jan 2018, ro at CeBiTec dot Uni-Bielefeld.DE wrote:

> https://gcc.gnu.org/bugzilla/show_bug.cgi?id=81968
> 
> --- Comment #42 from ro at CeBiTec dot Uni-Bielefeld.DE <ro at CeBiTec dot Uni-Bielefeld.DE> ---
> > --- Comment #41 from rguenther at suse dot de <rguenther at suse dot de> ---
> [...]
> >> Unfortunately not: it's really the section index pointing to the
> >> non-existing (i.e. eliminated) .gnu.debuglto_.debug_info section.
> >
> > But that section shouldn't be eliminated :/
> 
> IIUC it has been renamed to .debug_info:
> 
> * input object (cp_lto_pr42987_0.o):
> 
> Section Header[9]:  sh_name: .gnu.debuglto_.debug_info
>     sh_addr:      0               sh_flags:   0
>     sh_size:      0x3d4           sh_type:    [ SHT_PROGBITS ]
>     sh_offset:    0x7fb           sh_entsize: 0
>     sh_link:      0               sh_info:    0
>     sh_addralign: 0x1       
> 
> * output object (ccw3tETddebugobjtem):
> 
> Section Header[2]:  sh_name: .debug_info
>     sh_addr:      0               sh_flags:   0
>     sh_size:      0x3d4           sh_type:    [ SHT_PROGBITS ]
>     sh_offset:    0x84d           sh_entsize: 0
>     sh_link:      0               sh_info:    0
>     sh_addralign: 0x1       
> 
> without adapting section indices in .symtab.

Yes.  It should have retained [9] as section index.  Hmmm - you
have the patch removing sections in your tree?  I guess you need
to adapt (aka remap) the first_shndx section index I added with
the patch for the hpux ld issue.

> Besides, there's also a dangling
> 
> Section Header[6]:  sh_name: .rel.gnu.debuglto_.debug_info
>     sh_addr:      0               sh_flags:   0
>     sh_size:      0x8             sh_type:    [ SHT_REL ]
>     sh_offset:    0x11c8          sh_entsize: 0x8 (1 entry)
>     sh_link:      5               sh_info:    9
>     sh_addralign: 0x4       
> 
> in the output object.

that should have been used as the reloc section for the new section 2.
I see sh_info is still 9, it should be 2.  That's eventually
missing handling in the section removal patch.

I've committed the hpux fix so in case you re-base the patch and
fix up the first_shndx issue please attach the rebased one.