[COMMITTED] bfd,sparc: fix the .dynsym sh_info when stripping all symbols in ld

[Jose E. Marchesi]

Hi people!

I just installed the patch below, which fixes the generation of the
.dynsym's sh_info in ELF64 sparc targets when all symbols are stripped
with ld -s.

[Argh, while writing this down I just realized I wrote `sh_index'
instead of `sh_info' everywhere in the commit message and the ChangeLog
entry, glglgl. Will amend the ChangeLog entry in a subsequent commit.
Sorry about that mates!]

commit 6d0a6093c5fe82eb4c2b67d3d10fa44eeb0bc98b
Author: Jose E. Marchesi <***@oracle.com>
Date: Thu Oct 4 02:12:48 2018 -0700

bfd,sparc: fix the .dynsym sh_index when stripping all symbols in ld

The SPARC ELF BFD backend uses a hack in order to accomodate the
STT_REGISTER symbols mandated by the SPARC V9 ABI for 64-bit objects.
The hack works as follows:

- Early in `size_dynamic_symbols', it adds the dynamic STT_REGISTER
symbols and the corresponding DT_SPARC_REGISTER tags if needed,
i.e. if the input object has been annotated by the assembler to use
any of the global registers requiring annotations by the ABI.

The STT_REGISTER symbols are not local, but nevertheless they are
added to the end of the dynlocal linked list (eek, yes) to be fixed
"later". This is done so the symbols are emitted in the symtab.

- Consequently, when the `sh_info' field of the .dynsym section is
calculated in `bfd_elf_final_link' to be `local_dynsymcount + 1', it
may have the wrong value, since the real first global symbol is the
first STT_REGISTER symbol.

- However, this temporary inconsistency is fixed in the
`elf64_sparc_output_arch_syms' backend hook: the sh_index is
adjusted to its rightful value. So all is well and good.

However the 2015 changeset

commit 8539e4e89eb4c54bb6668582cd709765a3803588
Author: Alan Modra <***@gmail.com>
Date: Thu Jan 15 19:42:59 2015 +1030

Fix ARM fail of gap test

ld-elf/gap test was failing due to the ARM backend attempting to output
arch symbols when ld -s (strip all symbols) is in force. This patch
stops that happening and tidies the code a little.

made the `elf_backend_output_arch_syms' backend hook to not be called
when all symbols are to be stripped. This resulted in an incorrect
sh_index for .dynsym when a link is performed with -s (strip_all), in
64-bit sparc ELF objects.

This patch moves the sh_index adjusting code from the target
`output_arch_syms' to `finish_dynamic_sections'. It also removes the
strip_all check from `elf64_sparc_output_arch_syms', as the function
is no longer called in that case.

Tested in sparc64-linux-gnu and sparc-linux-gnu.
No regressions observed.

bfd/ChangeLog:

2018-10-04 Jose E. Marchesi <***@oracle.com>

* elf64-sparc.c (elf64_sparc_output_arch_syms): Do not correct the
impact of STT_REGISTER symbols in the dynsym sh_index here...
* elfxx-sparc.c (_bfd_sparc_elf_finish_dynamic_sections): ... but
do it here.

diff --git a/bfd/ChangeLog b/bfd/ChangeLog
index d2b5a57fe7..cc82ff1642 100644
--- a/bfd/ChangeLog
+++ b/bfd/ChangeLog
@@ -1,3 +1,10 @@
[phone] Jose E. Marchesi <***@oracle.com>
+
+ * elf64-sparc.c (elf64_sparc_output_arch_syms): Do notcorrect the
+ impact of STT_REGISTER symbols in the dynsym sh_index here...
+ * elfxx-sparc.c (_bfd_sparc_elf_finish_dynamic_sections): ...but
+ do it here.
+
2018-10-03 H.J. Lu <***@intel.com>

PR ld/23658
diff --git a/bfd/elf64-sparc.c b/bfd/elf64-sparc.c
index 41e1b7acf7..958ce44690 100644
--- a/bfd/elf64-sparc.c
+++ b/bfd/elf64-sparc.c
@@ -582,29 +582,6 @@ elf64_sparc_output_arch_syms (bfd *output_bfd ATTRIBUTE_UNUSED,
_bfd_sparc_elf_hash_table(info)->app_regs;
Elf_Internal_Sym sym;

- /* We arranged in size_dynamic_sections to put the STT_REGISTER entries
- at the end of the dynlocal list, so they came at the end of the local
- symbols in the symtab. Except that they aren't STB_LOCAL, so we need
- to back up symtab->sh_info. */
- if (elf_hash_table (info)->dynlocal)
- {
- bfd * dynobj = elf_hash_table (info)->dynobj;
- asection *dynsymsec = bfd_get_linker_section (dynobj, ".dynsym");
- struct elf_link_local_dynamic_entry *e;
-
- for (e = elf_hash_table (info)->dynlocal; e ; e = e->next)
- if (e->input_indx == -1)
- break;
- if (e)
- {
- elf_section_data (dynsymsec->output_section)->this_hdr.sh_info
- = e->dynindx;
- }
- }
-
- if (info->strip == strip_all)
- return TRUE;
-
for (reg = 0; reg < 4; reg++)
if (app_regs [reg].name != NULL)
{
diff --git a/bfd/elfxx-sparc.c b/bfd/elfxx-sparc.c
index bf143c400f..e5430fd55d 100644
--- a/bfd/elfxx-sparc.c
+++ b/bfd/elfxx-sparc.c
@@ -4792,7 +4792,25 @@ _bfd_sparc_elf_finish_dynamic_sections (bfd *output_bfd, struct bfd_link_info *i
htab = _bfd_sparc_elf_hash_table (info);
BFD_ASSERT (htab != NULL);
dynobj = htab->elf.dynobj;
-
+
+ /* We arranged in size_dynamic_sections to put the STT_REGISTER
+ entries at the end of the dynlocal list, so they came at the end
+ of the local symbols in the symtab. Except that they aren't
+ STB_LOCAL, so we need to back up symtab->sh_info. */
+ if (ABI_64_P (output_bfd)
+ && elf_hash_table (info)->dynlocal)
+ {
+ asection *dynsymsec = bfd_get_linker_section (dynobj, ".dynsym");
+ struct elf_link_local_dynamic_entry *e;
+
+ for (e = elf_hash_table (info)->dynlocal; e ; e = e->next)
+ if (e->input_indx == -1)
+ break;
+ if (e)
+ elf_section_data (dynsymsec->output_section)->this_hdr.sh_info
+ = e->dynindx;
+ }
+
sdyn = bfd_get_linker_section (dynobj, ".dynamic");

if (elf_hash_table (info)->dynamic_sections_created)