Re: [PATCH] LoongArch: ld: Simplify inserting IRELATIVE relocations to .rela.dyn

[mengqinggang <mengqinggang@loongson.cn>]

Hi,


For consistency, this patch also needs to be merged into the 2.41 branch.


在 2023/7/19 上午10:17, mengqinggang 写道:
> In LoongArch, the R_LARCH_IRELATIVE relocations for local ifunc symbols are
> in .rela.dyn. Before, this is done by loongarch_elf_finish_dynamic_sections.
> But this function is called after elf_link_sort_relocs, it need to find a
> null slot to insert IRELATIVE relocation.
>
> Now, it is processed by elf_loongarch_output_arch_local_syms before
> elf_link_sort_relocs, just need to call loongarch_elf_append_rela to
> insert IRELATIVE relocation.
>
> bfd/ChangeLog:
>
> 	* elfnn-loongarch.c (elfNN_allocate_local_ifunc_dynrelocs): Return
> 	type change to int.
> 	(loongarch_elf_size_dynamic_sections): Delete (void *).
> 	(loongarch_elf_finish_dynamic_symbol): Use loongarch_elf_append_rela
> 	insert IRELATIVE relocation to .rela.dyn.
> 	(elfNN_loongarch_finish_local_dynamic_symbol): Return type change to
> 	int.
> 	(loongarch_elf_finish_dynamic_sections): Delete process of local
> 	ifunc symbols.
> 	(elf_backend_output_arch_local_syms): New.
>
> ld/ChangeLog:
>
> 	* testsuite/ld-loongarch-elf/local-ifunc-reloc.d: Regenerated.
> ---
>   bfd/elfnn-loongarch.c                         | 67 +++++++++----------
>   .../ld-loongarch-elf/local-ifunc-reloc.d      |  2 +-
>   2 files changed, 34 insertions(+), 35 deletions(-)
>
> diff --git a/bfd/elfnn-loongarch.c b/bfd/elfnn-loongarch.c
> index d3d8419d80b..67a514b9b2b 100644
> --- a/bfd/elfnn-loongarch.c
> +++ b/bfd/elfnn-loongarch.c
> @@ -1538,7 +1538,7 @@ elfNN_allocate_ifunc_dynrelocs (struct elf_link_hash_entry *h, void *inf)
>   /* Allocate space in .plt, .got and associated reloc sections for
>      ifunc dynamic relocs.  */
>   
> -static bool
> +static int
>   elfNN_allocate_local_ifunc_dynrelocs (void **slot, void *inf)
>   {
>     struct elf_link_hash_entry *h = (struct elf_link_hash_entry *) *slot;
> @@ -1700,7 +1700,7 @@ loongarch_elf_size_dynamic_sections (bfd *output_bfd,
>   
>     /* Allocate .plt and .got entries, and space for local ifunc symbols.  */
>     htab_traverse (htab->loc_hash_table,
> -		 (void *) elfNN_allocate_local_ifunc_dynrelocs, info);
> +		 elfNN_allocate_local_ifunc_dynrelocs, info);
>   
>     /* Don't allocate .got.plt section if there are no PLT.  */
>     if (htab->elf.sgotplt && htab->elf.sgotplt->size == GOTPLT_HEADER_SIZE
> @@ -4001,12 +4001,6 @@ loongarch_elf_finish_dynamic_symbol (bfd *output_bfd,
>   {
>     struct loongarch_elf_link_hash_table *htab = loongarch_elf_hash_table (info);
>     const struct elf_backend_data *bed = get_elf_backend_data (output_bfd);
> -  asection *rela_dyn = bfd_get_section_by_name (output_bfd, ".rela.dyn");
> -  struct bfd_link_order *lo = NULL;
> -  Elf_Internal_Rela *slot = NULL, *last_slot = NULL;
> -
> -  if (rela_dyn)
> -    lo = rela_dyn->map_head.link_order;
>   
>     if (h->plt.offset != MINUS_ONE)
>       {
> @@ -4016,7 +4010,6 @@ loongarch_elf_finish_dynamic_symbol (bfd *output_bfd,
>         uint32_t plt_entry[PLT_ENTRY_INSNS];
>         bfd_byte *loc;
>         Elf_Internal_Rela rela;
> -      asection *rela_sec = NULL;
>   
>         if (htab->elf.splt)
>   	{
> @@ -4074,26 +4067,7 @@ loongarch_elf_finish_dynamic_symbol (bfd *output_bfd,
>   			       + h->root.u.def.section->output_section->vma
>   			       + h->root.u.def.section->output_offset);
>   
> -	  /* Find the space after dyn sort.  */
> -	  while (slot == last_slot || slot->r_offset != 0)
> -	    {
> -	      if (slot != last_slot)
> -		{
> -		  slot++;
> -		  continue;
> -		}
> -
> -	      BFD_ASSERT (lo != NULL);
> -	      rela_sec = lo->u.indirect.section;
> -	      lo = lo->next;
> -
> -	      slot = (Elf_Internal_Rela *)rela_sec->contents;
> -	      last_slot = (Elf_Internal_Rela *)(rela_sec->contents +
> -						rela_sec->size);
> -	    }
> -
> -	  bed->s->swap_reloca_out (output_bfd, &rela, (bfd_byte *)slot);
> -	  rela_sec->reloc_count++;
> +	  loongarch_elf_append_rela (output_bfd, relplt, &rela);
>   	}
>         else
>   	{
> @@ -4260,7 +4234,7 @@ loongarch_finish_dyn (bfd *output_bfd, struct bfd_link_info *info, bfd *dynobj,
>   /* Finish up local dynamic symbol handling.  We set the contents of
>      various dynamic sections here.  */
>   
> -static bool
> +static int
>   elfNN_loongarch_finish_local_dynamic_symbol (void **slot, void *inf)
>   {
>     struct elf_link_hash_entry *h = (struct elf_link_hash_entry *) *slot;
> @@ -4269,6 +4243,33 @@ elfNN_loongarch_finish_local_dynamic_symbol (void **slot, void *inf)
>     return loongarch_elf_finish_dynamic_symbol (info->output_bfd, info, h, NULL);
>   }
>   
> +/* Value of struct elf_backend_data->elf_backend_output_arch_local_syms,
> +   this function is called before elf_link_sort_relocs.
> +   So relocation R_LARCH_IRELATIVE for local ifunc can be append to
> +   .rela.dyn (.rela.got) by loongarch_elf_append_rela.  */
> +
> +static bool
> +elf_loongarch_output_arch_local_syms
> +  (bfd *output_bfd ATTRIBUTE_UNUSED,
> +   struct bfd_link_info *info,
> +   void *flaginfo ATTRIBUTE_UNUSED,
> +   int (*func) (void *, const char *,
> +		Elf_Internal_Sym *,
> +		asection *,
> +		struct elf_link_hash_entry *) ATTRIBUTE_UNUSED)
> +{
> +  struct loongarch_elf_link_hash_table *htab = loongarch_elf_hash_table (info);
> +  if (htab == NULL)
> +    return false;
> +
> +  /* Fill PLT and GOT entries for local STT_GNU_IFUNC symbols.  */
> +  htab_traverse (htab->loc_hash_table,
> +		 elfNN_loongarch_finish_local_dynamic_symbol,
> +		 info);
> +
> +  return true;
> +}
> +
>   static bool
>   loongarch_elf_finish_dynamic_sections (bfd *output_bfd,
>   				       struct bfd_link_info *info)
> @@ -4347,10 +4348,6 @@ loongarch_elf_finish_dynamic_sections (bfd *output_bfd,
>         elf_section_data (output_section)->this_hdr.sh_entsize = GOT_ENTRY_SIZE;
>       }
>   
> -  /* Fill PLT and GOT entries for local STT_GNU_IFUNC symbols.  */
> -  htab_traverse (htab->loc_hash_table,
> -		 (void *) elfNN_loongarch_finish_local_dynamic_symbol, info);
> -
>     return true;
>   }
>   
> @@ -4615,6 +4612,8 @@ elf_loongarch64_hash_symbol (struct elf_link_hash_entry *h)
>   #define elf_backend_size_dynamic_sections loongarch_elf_size_dynamic_sections
>   #define elf_backend_relocate_section loongarch_elf_relocate_section
>   #define elf_backend_finish_dynamic_symbol loongarch_elf_finish_dynamic_symbol
> +#define elf_backend_output_arch_local_syms \
> +  elf_loongarch_output_arch_local_syms
>   #define elf_backend_finish_dynamic_sections				   \
>     loongarch_elf_finish_dynamic_sections
>   #define elf_backend_object_p loongarch_elf_object_p
> diff --git a/ld/testsuite/ld-loongarch-elf/local-ifunc-reloc.d b/ld/testsuite/ld-loongarch-elf/local-ifunc-reloc.d
> index 29f2d3f36d3..bf73d9f2875 100644
> --- a/ld/testsuite/ld-loongarch-elf/local-ifunc-reloc.d
> +++ b/ld/testsuite/ld-loongarch-elf/local-ifunc-reloc.d
> @@ -6,5 +6,5 @@
>   
>   DYNAMIC RELOCATION RECORDS
>   OFFSET +TYPE +VALUE
> -[[:xdigit:]]+ R_LARCH_IRELATIVE +\*ABS\*\+0x[[:xdigit:]]+
>   [[:xdigit:]]+ R_LARCH_64 +test
> +[[:xdigit:]]+ R_LARCH_IRELATIVE +\*ABS\*\+0x[[:xdigit:]]+