Fix slowdown in ld -r for most common case of out-of-order relocs
I chose insertion sort since relocs are mostly sorted, but there is a common case we can handle better; A run of relocs put out of order due to not linking input files in order. PR 18867 * elflink.c (elf_link_adjust_relocs): Modify insertion sort to insert a run. Return status in case of malloc failure. Adjust callers.
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2015-09-16 Alan Modra <amodra@gmail.com>
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PR 18867
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* elflink.c (elf_link_adjust_relocs): Modify insertion sort to
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insert a run. Return status in case of malloc failure.
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Adjust callers.
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2015-09-15 Max Filippov <jcmvbkbc@gmail.com>
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* elf32-xtensa.c (elf_xtensa_be_plt_entry)
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@ -8193,7 +8193,7 @@ ext64b_r_offset (const void *p)
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referenced must be updated. Update all the relocations found in
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RELDATA. */
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static void
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static bfd_boolean
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elf_link_adjust_relocs (bfd *abfd,
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struct bfd_elf_section_reloc_data *reldata,
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bfd_boolean sort)
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@ -8259,7 +8259,7 @@ elf_link_adjust_relocs (bfd *abfd,
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bfd_vma r_off;
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size_t elt_size;
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bfd_byte *base, *end, *p, *loc;
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bfd_byte buf[sizeof (Elf64_External_Rela)];
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bfd_byte *buf = NULL;
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if (bed->s->arch_size == 32)
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{
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@ -8282,12 +8282,12 @@ elf_link_adjust_relocs (bfd *abfd,
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abort ();
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}
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/* Must use a stable sort here. Insertion sort, since the
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relocs are mostly sorted already. */
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/* Must use a stable sort here. A modified insertion sort,
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since the relocs are mostly sorted already. */
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elt_size = reldata->hdr->sh_entsize;
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base = reldata->hdr->contents;
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end = base + count * elt_size;
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if (elt_size > sizeof (buf))
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if (elt_size > sizeof (Elf64_External_Rela))
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abort ();
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/* Ensure the first element is lowest. This acts as a sentinel,
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@ -8307,12 +8307,13 @@ elf_link_adjust_relocs (bfd *abfd,
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/* Don't just swap *base and *loc as that changes the order
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of the original base[0] and base[1] if they happen to
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have the same r_offset. */
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memcpy (buf, loc, elt_size);
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bfd_byte onebuf[sizeof (Elf64_External_Rela)];
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memcpy (onebuf, loc, elt_size);
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memmove (base + elt_size, base, loc - base);
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memcpy (base, buf, elt_size);
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memcpy (base, onebuf, elt_size);
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}
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for (p = base + elt_size; (p += elt_size) < end; )
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for (p = base + elt_size; p < end; )
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{
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/* base to p is sorted, *p is next to insert. */
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r_off = (*ext_r_off) (p);
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@ -8323,15 +8324,48 @@ elf_link_adjust_relocs (bfd *abfd,
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loc += elt_size;
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if (loc != p)
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{
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memcpy (buf, p, elt_size);
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memmove (loc + elt_size, loc, p - loc);
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memcpy (loc, buf, elt_size);
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/* Chances are there is a run of relocs to insert here,
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from one of more input files. Files are not always
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linked in order due to the way elf_link_input_bfd is
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called. See pr17666. */
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size_t sortlen = p - loc;
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bfd_vma r_off2 = (*ext_r_off) (loc);
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size_t runlen = elt_size;
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size_t buf_size = 96 * 1024;
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while (p + runlen < end
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&& (sortlen <= buf_size
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|| runlen + elt_size <= buf_size)
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&& r_off2 > (*ext_r_off) (p + runlen))
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runlen += elt_size;
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if (buf == NULL)
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{
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buf = bfd_malloc (buf_size);
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if (buf == NULL)
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return FALSE;
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}
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if (runlen < sortlen)
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{
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memcpy (buf, p, runlen);
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memmove (loc + runlen, loc, sortlen);
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memcpy (loc, buf, runlen);
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}
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else
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{
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memcpy (buf, loc, sortlen);
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memmove (loc, p, runlen);
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memcpy (loc + runlen, buf, sortlen);
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}
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p += runlen;
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}
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else
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p += elt_size;
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}
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/* Hashes are no longer valid. */
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free (reldata->hashes);
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reldata->hashes = NULL;
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free (buf);
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}
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return TRUE;
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}
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struct elf_link_sort_rela
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@ -11577,10 +11611,12 @@ bfd_elf_final_link (bfd *abfd, struct bfd_link_info *info)
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continue;
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sort = bed->sort_relocs_p == NULL || (*bed->sort_relocs_p) (o);
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if (esdo->rel.hdr != NULL)
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elf_link_adjust_relocs (abfd, &esdo->rel, sort);
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if (esdo->rela.hdr != NULL)
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elf_link_adjust_relocs (abfd, &esdo->rela, sort);
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if (esdo->rel.hdr != NULL
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&& !elf_link_adjust_relocs (abfd, &esdo->rel, sort))
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return FALSE;
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if (esdo->rela.hdr != NULL
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&& !elf_link_adjust_relocs (abfd, &esdo->rela, sort))
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return FALSE;
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/* Set the reloc_count field to 0 to prevent write_relocs from
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trying to swap the relocs out itself. */
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