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Avoid creating COPY relocs if possible.

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* elf32-i386.c (elf_i386_check_relocs): Tweak condition under
	which .got created.  Mark symbols used by R_386_32 and R_386_PC32
	relocs as ELF_LINK_NON_GOT_REF to create COPY relocs only when the
	reloc is in a read-only section.  Instead, allocate space for a
	dynamic reloc to reference the library symbol directly.  Keep
	track of space we allocate using pcrel_relocs_copied.
	(discard_copies): Delete, and move code to ..
	(allocate_plt_and_got): ..here.  Rename to
	allocate_plt_and_got_and_discard_relocs.  Remove unneeded dynamic
	relocs for non-shared link.
	(elf_i386_size_dynamic_sections): Update calls to above functions.
	(elf_i386_relocate_section): Write out the dynamic relocs.  Add
	more ugly logic to avoid "unresolvable relocation" error.  Use
	htab shortcut in place of elf_hash_table macro.
	(elf_i386_finish_dynamic_sections): Allow that dynamic .got may
	not always be created now.
This commit is contained in:
Alan Modra 2001-06-23 05:54:15 +00:00
parent b4127474dc
commit 12d0ee4aca
2 changed files with 138 additions and 110 deletions
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20
bfd/ChangeLog
View file

@ -1,3 +1,23 @@
2001-06-23 Alan Modra <amodra@bigpond.net.au>
Avoid creating COPY relocs if possible.
* elf32-i386.c (elf_i386_check_relocs): Tweak condition under
which .got created. Mark symbols used by R_386_32 and R_386_PC32
relocs as ELF_LINK_NON_GOT_REF to create COPY relocs only when the
reloc is in a read-only section. Instead, allocate space for a
dynamic reloc to reference the library symbol directly. Keep
track of space we allocate using pcrel_relocs_copied.
(discard_copies): Delete, and move code to ..
(allocate_plt_and_got): ..here. Rename to
allocate_plt_and_got_and_discard_relocs. Remove unneeded dynamic
relocs for non-shared link.
(elf_i386_size_dynamic_sections): Update calls to above functions.
(elf_i386_relocate_section): Write out the dynamic relocs. Add
more ugly logic to avoid "unresolvable relocation" error. Use
htab shortcut in place of elf_hash_table macro.
(elf_i386_finish_dynamic_sections): Allow that dynamic .got may
not always be created now.
2001-06-20 Bo Thorsen <bo@suse.co.uk>
* elf64-x86-64.c (elf64_x86_64_relocate_section): Fix linking of

228
bfd/elf32-i386.c
View file

@ -43,12 +43,10 @@ static boolean elf_i386_check_relocs
const Elf_Internal_Rela *));
static boolean elf_i386_adjust_dynamic_symbol
PARAMS ((struct bfd_link_info *, struct elf_link_hash_entry *));
static boolean allocate_plt_and_got
static boolean allocate_plt_and_got_and_discard_relocs
PARAMS ((struct elf_link_hash_entry *, PTR));
static boolean elf_i386_size_dynamic_sections
PARAMS ((bfd *, struct bfd_link_info *));
static boolean discard_copies
PARAMS ((struct elf_link_hash_entry *, PTR));
static boolean elf_i386_relocate_section
PARAMS ((bfd *, struct bfd_link_info *, bfd *, asection *, bfd_byte *,
Elf_Internal_Rela *, Elf_Internal_Sym *, asection **));
@ -591,14 +589,15 @@ elf_i386_check_relocs (abfd, info, sec, relocs)
h = sym_hashes[r_symndx - symtab_hdr->sh_info];
/* Some relocs require a global offset table. */
if (dynobj == NULL)
if (htab->sgot == NULL)
{
switch (ELF32_R_TYPE (rel->r_info))
{
case R_386_GOT32:
case R_386_GOTOFF:
case R_386_GOTPC:
elf_hash_table (info)->dynobj = dynobj = abfd;
if (dynobj == NULL)
htab->root.dynobj = dynobj = abfd;
if (!create_got_section (dynobj, info))
return false;
break;
@ -673,19 +672,19 @@ elf_i386_check_relocs (abfd, info, sec, relocs)
case R_386_32:
case R_386_PC32:
if (h != NULL)
if (h != NULL && !info->shared)
{
h->elf_link_hash_flags |= ELF_LINK_NON_GOT_REF;
/* If this reloc is in a read-only section, we might
need a copy reloc. */
if ((sec->flags & SEC_READONLY) != 0)
h->elf_link_hash_flags |= ELF_LINK_NON_GOT_REF;
if (!info->shared)
{
/* We may need a .plt entry if the function this
reloc refers to is in a shared lib. */
if (h->plt.refcount == -1)
h->plt.refcount = 1;
else
h->plt.refcount += 1;
}
/* We may need a .plt entry if the function this reloc
refers to is in a shared lib. */
if (h->plt.refcount == -1)
h->plt.refcount = 1;
else
h->plt.refcount += 1;
}
/* If we are creating a shared library, and this is a reloc
@ -703,19 +702,32 @@ elf_i386_check_relocs (abfd, info, sec, relocs)
storing information in the relocs_copied field of the hash
table entry. A similar situation occurs when creating
shared libraries and symbol visibility changes render the
symbol local. */
if (info->shared
&& (sec->flags & SEC_ALLOC) != 0
&& (ELF32_R_TYPE (rel->r_info) != R_386_PC32
|| (h != NULL
&& (! info->symbolic
|| h->root.type == bfd_link_hash_defweak
|| (h->elf_link_hash_flags
& ELF_LINK_HASH_DEF_REGULAR) == 0))))
symbol local.
If on the other hand, we are creating an executable, we
may need to keep relocations for symbols satisfied by a
dynamic library if we manage to avoid copy relocs for the
symbol. */
if ((info->shared
&& (sec->flags & SEC_ALLOC) != 0
&& (ELF32_R_TYPE (rel->r_info) != R_386_PC32
|| (h != NULL
&& (! info->symbolic
|| h->root.type == bfd_link_hash_defweak
|| (h->elf_link_hash_flags
& ELF_LINK_HASH_DEF_REGULAR) == 0))))
|| (!info->shared
&& (sec->flags & SEC_ALLOC) != 0
&& h != NULL
&& (h->elf_link_hash_flags & ELF_LINK_NON_GOT_REF) == 0
&& (h->root.type == bfd_link_hash_defweak
|| (h->elf_link_hash_flags
& ELF_LINK_HASH_DEF_REGULAR) == 0)))
{
/* When creating a shared object, we must copy these
reloc types into the output file. We create a reloc
section in dynobj and make room for this reloc. */
/* We must copy these reloc types into the output file.
Create a reloc section in dynobj and make room for
this reloc. */
if (dynobj == NULL)
htab->root.dynobj = dynobj = abfd;
if (sreloc == NULL)
{
const char *name;
@ -767,8 +779,9 @@ elf_i386_check_relocs (abfd, info, sec, relocs)
that this function is only called if we are using an
elf_i386 linker hash table, which means that h is
really a pointer to an elf_i386_link_hash_entry. */
if (h != NULL
&& ELF32_R_TYPE (rel->r_info) == R_386_PC32)
if (!info->shared
|| (h != NULL
&& ELF32_R_TYPE (rel->r_info) == R_386_PC32))
{
struct elf_i386_link_hash_entry *eh;
struct elf_i386_pcrel_relocs_copied *p;
@ -1095,10 +1108,12 @@ elf_i386_adjust_dynamic_symbol (info, h)
|| ((H)->elf_link_hash_flags & ELF_LINK_FORCED_LOCAL) != 0))
/* Allocate space in .plt, .got and associated reloc sections for
global syms. */
global syms. Also discards space allocated for relocs in the
check_relocs function that we subsequently have found to be
unneeded. */
static boolean
allocate_plt_and_got (h, inf)
allocate_plt_and_got_and_discard_relocs (h, inf)
struct elf_link_hash_entry *h;
PTR inf;
{
@ -1175,6 +1190,29 @@ allocate_plt_and_got (h, inf)
else
h->got.offset = (bfd_vma) -1;
/* In the shared -Bsymbolic case, discard space allocated to copy
PC relative relocs against symbols which turn out to be defined
in regular objects. For the normal shared case, discard space
for relocs that have become local due to symbol visibility
changes. For the non-shared case, discard space for symbols
which turn out to need copy relocs or are not dynamic. */
if ((info->shared
&& (h->elf_link_hash_flags & ELF_LINK_HASH_DEF_REGULAR) != 0
&& ((h->elf_link_hash_flags & ELF_LINK_FORCED_LOCAL) != 0
|| info->symbolic))
|| (!info->shared
&& ((h->elf_link_hash_flags & ELF_LINK_NON_GOT_REF) != 0
|| h->dynindx == -1)))
{
struct elf_i386_link_hash_entry *eh;
struct elf_i386_pcrel_relocs_copied *c;
eh = (struct elf_i386_link_hash_entry *) h;
for (c = eh->pcrel_relocs_copied; c != NULL; c = c->next)
c->section->_raw_size -= c->count * sizeof (Elf32_External_Rel);
}
return true;
}
@ -1198,7 +1236,6 @@ elf_i386_size_dynamic_sections (output_bfd, info)
if (htab->root.dynamic_sections_created)
{
/* Set the contents of the .interp section to the interpreter. */
if (! info->shared)
{
@ -1244,20 +1281,12 @@ elf_i386_size_dynamic_sections (output_bfd, info)
}
}
/* Allocate global sym .plt and .got entries. */
/* Allocate global sym .plt and .got entries. Also discard all
unneeded relocs. */
elf_link_hash_traverse (&htab->root,
allocate_plt_and_got,
allocate_plt_and_got_and_discard_relocs,
(PTR) info);
/* If this is a -Bsymbolic shared link, then we need to discard all
PC relative relocs against symbols defined in a regular object.
We allocated space for them in the check_relocs routine, but we
will not fill them in in the relocate_section routine. */
if (info->shared)
elf_link_hash_traverse (&htab->root,
discard_copies,
(PTR) info);
/* The check_relocs and adjust_dynamic_symbol entry points have
determined the sizes of the various dynamic sections. Allocate
memory for them. */
@ -1384,41 +1413,6 @@ elf_i386_size_dynamic_sections (output_bfd, info)
return true;
}
/* This function is called via elf_link_hash_traverse if we are
creating a shared object. In the -Bsymbolic case, it discards the
space allocated to copy PC relative relocs against symbols which
are defined in regular objects. For the normal non-symbolic case,
we also discard space for relocs that have become local due to
symbol visibility changes. We allocated space for them in the
check_relocs routine, but we won't fill them in in the
relocate_section routine. */
static boolean
discard_copies (h, inf)
struct elf_link_hash_entry *h;
PTR inf;
{
struct elf_i386_pcrel_relocs_copied *s;
struct bfd_link_info *info;
struct elf_i386_link_hash_entry *eh;
info = (struct bfd_link_info *) inf;
eh = (struct elf_i386_link_hash_entry *) h;
/* If a symbol has been forced local or we have found a regular
definition for the symbolic link case, then we won't be needing
any relocs. */
if ((eh->root.elf_link_hash_flags & ELF_LINK_HASH_DEF_REGULAR) != 0
&& ((eh->root.elf_link_hash_flags & ELF_LINK_FORCED_LOCAL) != 0
|| info->symbolic))
{
for (s = eh->pcrel_relocs_copied; s != NULL; s = s->next)
s->section->_raw_size -= s->count * sizeof (Elf32_External_Rel);
}
return true;
}
/* Relocate an i386 ELF section. */
static boolean
@ -1539,12 +1533,18 @@ elf_i386_relocate_section (output_bfd, info, input_bfd, input_section,
& ELF_LINK_FORCED_LOCAL))
&& (h->elf_link_hash_flags
& ELF_LINK_HASH_DEF_REGULAR)))
|| (info->shared
&& ((! info->symbolic && h->dynindx != -1)
|| (h->elf_link_hash_flags
& ELF_LINK_HASH_DEF_REGULAR) == 0)
&& (r_type == R_386_32
|| r_type == R_386_PC32)
|| ((r_type == R_386_32
|| r_type == R_386_PC32)
&& ((info->shared
&& ((!info->symbolic && h->dynindx != -1)
|| (h->elf_link_hash_flags
& ELF_LINK_HASH_DEF_REGULAR) == 0))
|| (!info->shared
&& h->dynindx != -1
&& (h->elf_link_hash_flags
& ELF_LINK_NON_GOT_REF) == 0
&& (h->elf_link_hash_flags
& ELF_LINK_HASH_DEF_REGULAR) == 0))
&& ((input_section->flags & SEC_ALLOC) != 0
/* DWARF will emit R_386_32 relocations in its
sections against symbols defined externally
@ -1723,14 +1723,22 @@ elf_i386_relocate_section (output_bfd, info, input_bfd, input_section,
case R_386_32:
case R_386_PC32:
if (info->shared
&& (input_section->flags & SEC_ALLOC) != 0
&& (r_type != R_386_PC32
|| (h != NULL
&& h->dynindx != -1
&& (! info->symbolic
|| (h->elf_link_hash_flags
& ELF_LINK_HASH_DEF_REGULAR) == 0))))
if ((info->shared
&& (input_section->flags & SEC_ALLOC) != 0
&& (r_type != R_386_PC32
|| (h != NULL
&& h->dynindx != -1
&& (! info->symbolic
|| (h->elf_link_hash_flags
& ELF_LINK_HASH_DEF_REGULAR) == 0))))
|| (!info->shared
&& (input_section->flags & SEC_ALLOC) != 0
&& h != NULL
&& h->dynindx != -1
&& (h->elf_link_hash_flags & ELF_LINK_NON_GOT_REF) == 0
&& (h->root.type == bfd_link_hash_defweak
|| (h->elf_link_hash_flags
& ELF_LINK_HASH_DEF_REGULAR) == 0)))
{
Elf_Internal_Rel outrel;
boolean skip, relocate;
@ -1780,8 +1788,7 @@ elf_i386_relocate_section (output_bfd, info, input_bfd, input_section,
bfd_vma off;
off = (_bfd_stab_section_offset
(output_bfd, &elf_hash_table (info)->stab_info,
input_section,
(output_bfd, htab->root.stab_info, input_section,
&elf_section_data (input_section)->stab_info,
rel->r_offset));
if (off == (bfd_vma) -1)
@ -1808,7 +1815,8 @@ elf_i386_relocate_section (output_bfd, info, input_bfd, input_section,
/* h->dynindx may be -1 if this symbol was marked to
become local. */
if (h == NULL
|| ((info->symbolic || h->dynindx == -1)
|| (info->shared
&& (info->symbolic || h->dynindx == -1)
&& (h->elf_link_hash_flags
& ELF_LINK_HASH_DEF_REGULAR) != 0))
{
@ -2056,15 +2064,13 @@ elf_i386_finish_dynamic_sections (output_bfd, info)
htab = elf_i386_hash_table (info);
dynobj = htab->root.dynobj;
BFD_ASSERT (htab->sgot != NULL);
sdyn = bfd_get_section_by_name (dynobj, ".dynamic");
if (htab->root.dynamic_sections_created)
{
Elf32_External_Dyn *dyncon, *dynconend;
BFD_ASSERT (sdyn != NULL);
BFD_ASSERT (sdyn != NULL && htab->sgot != NULL);
dyncon = (Elf32_External_Dyn *) sdyn->contents;
dynconend = (Elf32_External_Dyn *) (sdyn->contents + sdyn->_raw_size);
@ -2148,19 +2154,21 @@ elf_i386_finish_dynamic_sections (output_bfd, info)
}
}
/* Fill in the first three entries in the global offset table. */
if (htab->sgotplt->_raw_size > 0)
if (htab->sgotplt)
{
bfd_put_32 (output_bfd,
(sdyn == NULL ? (bfd_vma) 0
: sdyn->output_section->vma + sdyn->output_offset),
htab->sgotplt->contents);
bfd_put_32 (output_bfd, (bfd_vma) 0, htab->sgotplt->contents + 4);
bfd_put_32 (output_bfd, (bfd_vma) 0, htab->sgotplt->contents + 8);
/* Fill in the first three entries in the global offset table. */
if (htab->sgotplt->_raw_size > 0)
{
bfd_put_32 (output_bfd,
(sdyn == NULL ? (bfd_vma) 0
: sdyn->output_section->vma + sdyn->output_offset),
htab->sgotplt->contents);
bfd_put_32 (output_bfd, (bfd_vma) 0, htab->sgotplt->contents + 4);
bfd_put_32 (output_bfd, (bfd_vma) 0, htab->sgotplt->contents + 8);
}
elf_section_data (htab->sgotplt->output_section)->this_hdr.sh_entsize = 4;
}
elf_section_data (htab->sgotplt->output_section)->this_hdr.sh_entsize = 4;
return true;
}