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Use stable sort for ld -r relocs

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A number of targets emit multiple relocs at a given r_offset, and
depend on those relocs staying in their original order.

	PR 18867
	* elflink.c (cmp_ext32l_r_offset, cmp_ext32b_r_offset): Delete.
	(cmp_ext64l_r_offset, cmp_ext64b_r_offset): Delete.
	(ext32l_r_offset, ext32b_r_offset, ext64l_r_offset, ext64b_r_offset):
	New functions.
	(elf_link_adjust_relocs): Use an insertion sort to sort relocs.
This commit is contained in:
Alan Modra 2015-08-26 17:32:08 +09:30
parent c97c330ba8
commit 0e28778672
2 changed files with 86 additions and 72 deletions
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9
bfd/ChangeLog
View File

@ -1,3 +1,12 @@
2015-08-26 Alan Modra <amodra@gmail.com>
PR 18867
* elflink.c (cmp_ext32l_r_offset, cmp_ext32b_r_offset): Delete.
(cmp_ext64l_r_offset, cmp_ext64b_r_offset): Delete.
(ext32l_r_offset, ext32b_r_offset, ext64l_r_offset, ext64b_r_offset):
New functions.
(elf_link_adjust_relocs): Use an insertion sort to sort relocs.
2015-08-26 Matthew Fortune <matthew.fortune@imgtec.com>
PR ld/18401

149
bfd/elflink.c
View File

@ -8102,10 +8102,12 @@ bfd_elf_perform_complex_relocation (bfd *input_bfd,
return r;
}
/* qsort comparison functions sorting external relocs by r_offset. */
/* Functions to read r_offset from external (target order) reloc
entry. Faster than bfd_getl32 et al, because we let the compiler
know the value is aligned. */
static int
cmp_ext32l_r_offset (const void *p, const void *q)
static bfd_vma
ext32l_r_offset (const void *p)
{
union aligned32
{
@ -8113,27 +8115,17 @@ cmp_ext32l_r_offset (const void *p, const void *q)
unsigned char c[4];
};
const union aligned32 *a
= (const union aligned32 *) ((const Elf32_External_Rel *) p)->r_offset;
const union aligned32 *b
= (const union aligned32 *) ((const Elf32_External_Rel *) q)->r_offset;
= (const union aligned32 *) &((const Elf32_External_Rel *) p)->r_offset;
uint32_t aval = ( (uint32_t) a->c[0]
| (uint32_t) a->c[1] << 8
| (uint32_t) a->c[2] << 16
| (uint32_t) a->c[3] << 24);
uint32_t bval = ( (uint32_t) b->c[0]
| (uint32_t) b->c[1] << 8
| (uint32_t) b->c[2] << 16
| (uint32_t) b->c[3] << 24);
if (aval < bval)
return -1;
else if (aval > bval)
return 1;
return 0;
return aval;
}
static int
cmp_ext32b_r_offset (const void *p, const void *q)
static bfd_vma
ext32b_r_offset (const void *p)
{
union aligned32
{
@ -8141,28 +8133,18 @@ cmp_ext32b_r_offset (const void *p, const void *q)
unsigned char c[4];
};
const union aligned32 *a
= (const union aligned32 *) ((const Elf32_External_Rel *) p)->r_offset;
const union aligned32 *b
= (const union aligned32 *) ((const Elf32_External_Rel *) q)->r_offset;
= (const union aligned32 *) &((const Elf32_External_Rel *) p)->r_offset;
uint32_t aval = ( (uint32_t) a->c[0] << 24
| (uint32_t) a->c[1] << 16
| (uint32_t) a->c[2] << 8
| (uint32_t) a->c[3]);
uint32_t bval = ( (uint32_t) b->c[0] << 24
| (uint32_t) b->c[1] << 16
| (uint32_t) b->c[2] << 8
| (uint32_t) b->c[3]);
if (aval < bval)
return -1;
else if (aval > bval)
return 1;
return 0;
return aval;
}
#ifdef BFD_HOST_64_BIT
static int
cmp_ext64l_r_offset (const void *p, const void *q)
static bfd_vma
ext64l_r_offset (const void *p)
{
union aligned64
{
@ -8170,9 +8152,7 @@ cmp_ext64l_r_offset (const void *p, const void *q)
unsigned char c[8];
};
const union aligned64 *a
= (const union aligned64 *) ((const Elf64_External_Rel *) p)->r_offset;
const union aligned64 *b
= (const union aligned64 *) ((const Elf64_External_Rel *) q)->r_offset;
= (const union aligned64 *) &((const Elf64_External_Rel *) p)->r_offset;
uint64_t aval = ( (uint64_t) a->c[0]
| (uint64_t) a->c[1] << 8
@ -8182,23 +8162,11 @@ cmp_ext64l_r_offset (const void *p, const void *q)
| (uint64_t) a->c[5] << 40
| (uint64_t) a->c[6] << 48
| (uint64_t) a->c[7] << 56);
uint64_t bval = ( (uint64_t) b->c[0]
| (uint64_t) b->c[1] << 8
| (uint64_t) b->c[2] << 16
| (uint64_t) b->c[3] << 24
| (uint64_t) b->c[4] << 32
| (uint64_t) b->c[5] << 40
| (uint64_t) b->c[6] << 48
| (uint64_t) b->c[7] << 56);
if (aval < bval)
return -1;
else if (aval > bval)
return 1;
return 0;
return aval;
}
static int
cmp_ext64b_r_offset (const void *p, const void *q)
static bfd_vma
ext64b_r_offset (const void *p)
{
union aligned64
{
@ -8206,9 +8174,7 @@ cmp_ext64b_r_offset (const void *p, const void *q)
unsigned char c[8];
};
const union aligned64 *a
= (const union aligned64 *) ((const Elf64_External_Rel *) p)->r_offset;
const union aligned64 *b
= (const union aligned64 *) ((const Elf64_External_Rel *) q)->r_offset;
= (const union aligned64 *) &((const Elf64_External_Rel *) p)->r_offset;
uint64_t aval = ( (uint64_t) a->c[0] << 56
| (uint64_t) a->c[1] << 48
@ -8218,19 +8184,7 @@ cmp_ext64b_r_offset (const void *p, const void *q)
| (uint64_t) a->c[5] << 16
| (uint64_t) a->c[6] << 8
| (uint64_t) a->c[7]);
uint64_t bval = ( (uint64_t) b->c[0] << 56
| (uint64_t) b->c[1] << 48
| (uint64_t) b->c[2] << 40
| (uint64_t) b->c[3] << 32
| (uint64_t) b->c[4] << 24
| (uint64_t) b->c[5] << 16
| (uint64_t) b->c[6] << 8
| (uint64_t) b->c[7]);
if (aval < bval)
return -1;
else if (aval > bval)
return 1;
return 0;
return aval;
}
#endif
@ -8299,16 +8253,20 @@ elf_link_adjust_relocs (bfd *abfd,
(*swap_out) (abfd, irela, erela);
}
if (sort)
if (sort && count != 0)
{
int (*compare) (const void *, const void *);
bfd_vma (*ext_r_off) (const void *);
bfd_vma r_off;
size_t elt_size;
bfd_byte *base, *end, *p, *loc;
bfd_byte buf[sizeof (Elf64_External_Rela)];
if (bed->s->arch_size == 32)
{
if (abfd->xvec->header_byteorder == BFD_ENDIAN_LITTLE)
compare = cmp_ext32l_r_offset;
ext_r_off = ext32l_r_offset;
else if (abfd->xvec->header_byteorder == BFD_ENDIAN_BIG)
compare = cmp_ext32b_r_offset;
ext_r_off = ext32b_r_offset;
else
abort ();
}
@ -8316,14 +8274,61 @@ elf_link_adjust_relocs (bfd *abfd,
{
#ifdef BFD_HOST_64_BIT
if (abfd->xvec->header_byteorder == BFD_ENDIAN_LITTLE)
compare = cmp_ext64l_r_offset;
ext_r_off = ext64l_r_offset;
else if (abfd->xvec->header_byteorder == BFD_ENDIAN_BIG)
compare = cmp_ext64b_r_offset;
ext_r_off = ext64b_r_offset;
else
#endif
abort ();
}
qsort (reldata->hdr->contents, count, reldata->hdr->sh_entsize, compare);
/* Must use a stable sort here. Insertion sort, since the
relocs are mostly sorted already. */
elt_size = reldata->hdr->sh_entsize;
base = reldata->hdr->contents;
end = base + count * elt_size;
if (elt_size > sizeof (buf))
abort ();
/* Ensure the first element is lowest. This acts as a sentinel,
speeding the main loop below. */
r_off = (*ext_r_off) (base);
for (p = loc = base; (p += elt_size) < end; )
{
bfd_vma r_off2 = (*ext_r_off) (p);
if (r_off > r_off2)
{
r_off = r_off2;
loc = p;
}
}
if (loc != base)
{
/* Don't just swap *base and *loc as that changes the order
of the original base[0] and base[1] if they happen to
have the same r_offset. */
memcpy (buf, loc, elt_size);
memmove (base + elt_size, base, loc - base);
memcpy (base, buf, elt_size);
}
for (p = base + elt_size; (p += elt_size) < end; )
{
/* base to p is sorted, *p is next to insert. */
r_off = (*ext_r_off) (p);
/* Search the sorted region for location to insert. */
loc = p - elt_size;
while (r_off < (*ext_r_off) (loc))
loc -= elt_size;
loc += elt_size;
if (loc != p)
{
memcpy (buf, p, elt_size);
memmove (loc + elt_size, loc, p - loc);
memcpy (loc, buf, elt_size);
}
}
/* Hashes are no longer valid. */
free (reldata->hashes);
reldata->hashes = NULL;
}