[Patch, AARCH64] gc-section support

[Venkataramanan Kumar]

Hi Maintainers,

Attached is a small patch that enables gc-section support for AARCH64.

In the sweep hook I have handled TLS and GOT related relocs that were
already supported in that file.

Make check passes along with the gc-section tests.

I used the patched binutils to build gcc for aarch64-none-elf target
and tested the gcc testsuite in v8 foundation model.

Ok for trunk?

regards,
Venkat,


ChangeLog:

BFD

2013-02-21  Venkataramanan Kumar  <venkataramanan.kumar@linaro.org>

        * elf64-aarch64.c (elf_backend_can_gc_sections): Enable
gc-section support.
        (elf64_aarch64_gc_sweep_hook): Handle GOT, TLS and PLT related relocs.

LD

2013-02-21  Venkataramanan Kumar  <venkataramanan.kumar@linaro.org>

        * lib/ld-lib.exp (check_gc_sections_available): Remove aarch64
from list of
        targets that don't support gc-section.
-------------- next part --------------
Index: bfd/elf64-aarch64.c
===================================================================
RCS file: /cvs/src/src/bfd/elf64-aarch64.c,v
retrieving revision 1.9
diff -r1.9 elf64-aarch64.c
4869d4868
< /* Update the got entry reference counts for the section being removed.  */
4870a4870
> /* Update the got entry reference counts for the section being removed.  */
4877a4878,5010
>   struct elf64_aarch64_link_hash_table *htab;
>   Elf_Internal_Shdr *symtab_hdr;
>   struct elf_link_hash_entry **sym_hashes;
>   bfd_signed_vma *local_got_refcounts;
>   const Elf_Internal_Rela *rel, *relend;
> 
>   if (info->relocatable)
> 	return TRUE;
> 
>   htab = elf64_aarch64_hash_table (info);
> 
>   if (htab == NULL)
> 	return FALSE;
> 
>   elf_section_data (sec)->local_dynrel = NULL;
> 
>   symtab_hdr = &elf_symtab_hdr (abfd);
>   sym_hashes = elf_sym_hashes (abfd);
> 
>   local_got_refcounts = elf_local_got_refcounts (abfd);
> 
>   relend = relocs + sec->reloc_count;
>   for (rel = relocs; rel < relend; rel++)
>     {
>       unsigned long r_symndx;
>       unsigned int r_type;
>       struct elf_link_hash_entry *h = NULL;
> 
>       r_symndx = ELF64_R_SYM (rel->r_info);
>       if (r_symndx >= symtab_hdr->sh_info)
>         {
>           struct elf64_aarch64_link_hash_entry *eh;
>           struct elf_dyn_relocs **pp;
>           struct elf_dyn_relocs *p;
> 
>           h = sym_hashes[r_symndx - symtab_hdr->sh_info];
>           while (h->root.type == bfd_link_hash_indirect
>                  || h->root.type == bfd_link_hash_warning)
>             h = (struct elf_link_hash_entry *) h->root.u.i.link;
>           eh = (struct elf64_aarch64_link_hash_entry *) h;
> 
>           for (pp = &eh->dyn_relocs; (p = *pp) != NULL; pp = &p->next)
>             if (p->sec == sec)
>               {
>                 /* Everything must go for SEC.  */
>                 *pp = p->next;
>                 break;
>               }
>         }
>       else
>         {
>           Elf_Internal_Sym *isym;
> 
>           /* A local symbol.  */
>           isym = bfd_sym_from_r_symndx (&htab->sym_cache,
>                                         abfd, r_symndx);
>           if (isym == NULL)
>             return FALSE;
>         }
> 
>       r_type = ELF64_R_TYPE (rel->r_info);
>       r_type = aarch64_tls_transition (abfd,info, r_type, h ,r_symndx);
>       switch (r_type)
>         {
>         case R_AARCH64_LD64_GOT_LO12_NC:
>         case R_AARCH64_GOT_LD_PREL19:
>         case R_AARCH64_ADR_GOT_PAGE:
>         case R_AARCH64_TLSGD_ADR_PAGE21:
>         case R_AARCH64_TLSGD_ADD_LO12_NC:
>         case R_AARCH64_TLSIE_ADR_GOTTPREL_PAGE21:
>         case R_AARCH64_TLSIE_LD64_GOTTPREL_LO12_NC:
>         case R_AARCH64_TLSLE_ADD_TPREL_LO12:
>         case R_AARCH64_TLSLE_ADD_TPREL_HI12:
>         case R_AARCH64_TLSLE_ADD_TPREL_LO12_NC:
>         case R_AARCH64_TLSLE_MOVW_TPREL_G2:
>         case R_AARCH64_TLSLE_MOVW_TPREL_G1:
>         case R_AARCH64_TLSLE_MOVW_TPREL_G1_NC:
>         case R_AARCH64_TLSLE_MOVW_TPREL_G0:
>         case R_AARCH64_TLSLE_MOVW_TPREL_G0_NC:
>         case R_AARCH64_TLSDESC_ADR_PAGE:
>         case R_AARCH64_TLSDESC_ADD_LO12_NC:
>         case R_AARCH64_TLSDESC_LD64_LO12_NC:
> 
> 	        if (h != NULL)
>             {
>               if (h->got.refcount > 0)
>                 h->got.refcount -= 1;
>             }
>           else if (local_got_refcounts != NULL)
>             {
>               if (local_got_refcounts[r_symndx] > 0)
>                 local_got_refcounts[r_symndx] -= 1;
>             }
>           break;
> 
>         case R_AARCH64_ADR_PREL_PG_HI21_NC:
>         case R_AARCH64_ADR_PREL_PG_HI21:
>         case R_AARCH64_ADR_PREL_LO21:
>           if (h != NULL && info->executable)
>             {
>              if (h->plt.refcount > 0)
>                 h->plt.refcount -= 1;
>             }
> 	        break;
> 	      case R_AARCH64_CALL26:
>         case R_AARCH64_JUMP26:
>           /* If this is a local symbol then we resolve it
>              directly without creating a PLT entry.  */
>           if (h == NULL)
>           	continue;
> 
>           if (h->plt.refcount > 0)
>           	h->plt.refcount -= 1;
> 
>           break;
> 
>         case R_AARCH64_ABS64:
>         
> 	        if (h != NULL && info->executable)
>             {
>             	if (h->plt.refcount > 0)
>             		h->plt.refcount -= 1;
> 
>             }
> 	        break;
>         
> 	     default:
>           break;
> 
>         }
> 
>     }
> 
7052c7185
< #define elf_backend_can_gc_sections    0
---
> #define elf_backend_can_gc_sections    1 
Index: ld/testsuite/lib/ld-lib.exp
===================================================================
RCS file: /cvs/src/src/ld/testsuite/lib/ld-lib.exp,v
retrieving revision 1.103
diff -r1.103 ld-lib.exp
1521,1522c1521
< 	if {[istarget aarch64*-*-*]
< 	     || [istarget arc-*-*]
---
> 	if {[istarget arc-*-*]