Fix performance regression on x86 with ld -r

Similar fix to "commit c316a17c40e44e8798b34ff84130904f2e7a53de".

	* elf32-i386.c (elf_i386_relocate_section): Use read and write
	pointers to reloc array, rather than memmove when deleting a
	reloc.  Don't use RELOC_AGAINST_DISCARDED_SECTION.  Adjust
	reloc counts at end of loop.
	* elf64-x86-64.c (elf_x86_64_relocate_section): Likewise.
This commit is contained in:
H.J. Lu
2015-11-09 23:49:02 -08:00
parent 6637a4265e
commit 60f2e42e00
3 changed files with 98 additions and 8 deletions

View File

@ -1,3 +1,11 @@
2015-11-09 H.J. Lu <hongjiu.lu@intel.com>
* elf32-i386.c (elf_i386_relocate_section): Use read and write
pointers to reloc array, rather than memmove when deleting a
reloc. Don't use RELOC_AGAINST_DISCARDED_SECTION. Adjust
reloc counts at end of loop.
* elf64-x86-64.c (elf_x86_64_relocate_section): Likewise.
2015-11-10 Alan Modra <amodra@gmail.com>
* elf64-ppc.c (ppc64_elf_relocate_section): Use read and write

View File

@ -3599,6 +3599,7 @@ elf_i386_relocate_section (bfd *output_bfd,
bfd_vma *local_got_offsets;
bfd_vma *local_tlsdesc_gotents;
Elf_Internal_Rela *rel;
Elf_Internal_Rela *wrel;
Elf_Internal_Rela *relend;
bfd_boolean is_vxworks_tls;
unsigned plt_entry_size;
@ -3623,9 +3624,9 @@ elf_i386_relocate_section (bfd *output_bfd,
plt_entry_size = GET_PLT_ENTRY_SIZE (output_bfd);
rel = relocs;
rel = wrel = relocs;
relend = relocs + input_section->reloc_count;
for (; rel < relend; rel++)
for (; rel < relend; wrel++, rel++)
{
unsigned int r_type;
reloc_howto_type *howto;
@ -3772,8 +3773,22 @@ elf_i386_relocate_section (bfd *output_bfd,
}
if (sec != NULL && discarded_section (sec))
RELOC_AGAINST_DISCARDED_SECTION (info, input_bfd, input_section,
rel, 1, relend, howto, 0, contents);
{
_bfd_clear_contents (howto, input_bfd, input_section,
contents + rel->r_offset);
wrel->r_offset = rel->r_offset;
wrel->r_info = 0;
wrel->r_addend = 0;
/* For ld -r, remove relocations in debug sections against
sections defined in discarded sections. Not done for
eh_frame editing code expects to be present. */
if (bfd_link_relocatable (info)
&& (input_section->flags & SEC_DEBUGGING))
wrel--;
continue;
}
if (bfd_link_relocatable (info))
continue;
@ -4365,6 +4380,7 @@ r_386_got32:
contents + roff);
/* Skip R_386_PC32/R_386_PLT32. */
rel++;
wrel++;
continue;
}
else if (ELF32_R_TYPE (rel->r_info) == R_386_TLS_GOTDESC)
@ -4704,6 +4720,7 @@ r_386_got32:
contents + roff + 8);
/* Skip R_386_PLT32. */
rel++;
wrel++;
continue;
}
else if (ELF32_R_TYPE (rel->r_info) == R_386_TLS_GOTDESC)
@ -4801,6 +4818,7 @@ r_386_got32:
"\x65\xa1\0\0\0\0\x90\x8d\x74\x26", 11);
/* Skip R_386_PC32/R_386_PLT32. */
rel++;
wrel++;
continue;
}
@ -4942,6 +4960,29 @@ check_relocation_error:
return FALSE;
}
}
if (wrel != rel)
*wrel = *rel;
}
if (wrel != rel)
{
Elf_Internal_Shdr *rel_hdr;
size_t deleted = rel - wrel;
rel_hdr = _bfd_elf_single_rel_hdr (input_section->output_section);
rel_hdr->sh_size -= rel_hdr->sh_entsize * deleted;
if (rel_hdr->sh_size == 0)
{
/* It is too late to remove an empty reloc section. Leave
one NONE reloc.
??? What is wrong with an empty section??? */
rel_hdr->sh_size = rel_hdr->sh_entsize;
deleted -= 1;
}
rel_hdr = _bfd_elf_single_rel_hdr (input_section);
rel_hdr->sh_size -= rel_hdr->sh_entsize * deleted;
input_section->reloc_count -= deleted;
}
return TRUE;

View File

@ -3866,6 +3866,7 @@ elf_x86_64_relocate_section (bfd *output_bfd,
bfd_vma *local_got_offsets;
bfd_vma *local_tlsdesc_gotents;
Elf_Internal_Rela *rel;
Elf_Internal_Rela *wrel;
Elf_Internal_Rela *relend;
const unsigned int plt_entry_size = GET_PLT_ENTRY_SIZE (info->output_bfd);
@ -3881,9 +3882,9 @@ elf_x86_64_relocate_section (bfd *output_bfd,
elf_x86_64_set_tls_module_base (info);
rel = relocs;
rel = wrel = relocs;
relend = relocs + input_section->reloc_count;
for (; rel < relend; rel++)
for (; rel < relend; wrel++, rel++)
{
unsigned int r_type;
reloc_howto_type *howto;
@ -3961,8 +3962,22 @@ elf_x86_64_relocate_section (bfd *output_bfd,
}
if (sec != NULL && discarded_section (sec))
RELOC_AGAINST_DISCARDED_SECTION (info, input_bfd, input_section,
rel, 1, relend, howto, 0, contents);
{
_bfd_clear_contents (howto, input_bfd, input_section,
contents + rel->r_offset);
wrel->r_offset = rel->r_offset;
wrel->r_info = 0;
wrel->r_addend = 0;
/* For ld -r, remove relocations in debug sections against
sections defined in discarded sections. Not done for
eh_frame editing code expects to be present. */
if (bfd_link_relocatable (info)
&& (input_section->flags & SEC_DEBUGGING))
wrel--;
continue;
}
if (bfd_link_relocatable (info))
continue;
@ -4782,6 +4797,7 @@ direct:
contents + roff + 8 + largepic);
/* Skip R_X86_64_PC32/R_X86_64_PLT32/R_X86_64_PLTOFF64. */
rel++;
wrel++;
continue;
}
else if (ELF32_R_TYPE (rel->r_info) == R_X86_64_GOTPC32_TLSDESC)
@ -5064,6 +5080,7 @@ direct:
contents + roff + 8 + largepic);
/* Skip R_X86_64_PLT32/R_X86_64_PLTOFF64. */
rel++;
wrel++;
continue;
}
else if (ELF32_R_TYPE (rel->r_info) == R_X86_64_GOTPC32_TLSDESC)
@ -5148,6 +5165,7 @@ direct:
"\x0f\x1f\x40\x00\x64\x8b\x04\x25\0\0\0", 12);
/* Skip R_X86_64_PC32/R_X86_64_PLT32/R_X86_64_PLTOFF64. */
rel++;
wrel++;
continue;
}
@ -5264,6 +5282,29 @@ check_relocation_error:
return FALSE;
}
}
if (wrel != rel)
*wrel = *rel;
}
if (wrel != rel)
{
Elf_Internal_Shdr *rel_hdr;
size_t deleted = rel - wrel;
rel_hdr = _bfd_elf_single_rel_hdr (input_section->output_section);
rel_hdr->sh_size -= rel_hdr->sh_entsize * deleted;
if (rel_hdr->sh_size == 0)
{
/* It is too late to remove an empty reloc section. Leave
one NONE reloc.
??? What is wrong with an empty section??? */
rel_hdr->sh_size = rel_hdr->sh_entsize;
deleted -= 1;
}
rel_hdr = _bfd_elf_single_rel_hdr (input_section);
rel_hdr->sh_size -= rel_hdr->sh_entsize * deleted;
input_section->reloc_count -= deleted;
}
return TRUE;