Here is one implementation of ELF sharable section proposal:
http://groups-beta.google.com/group/generic-abi/browse_thread/thread/bca08f6560f61b0d
Several people have expressed interests. I post it here for comments.
I used OS specific values. If we get consensus, I can change those
values to generic range.
H.J.
bfd/
2007-01-04 H.J. Lu <[EMAIL PROTECTED]>
* elf-bfd.h (_bfd_elf_sharable_com_section): New.
(_bfd_elf_add_sharable_symbol): Likewise.
(_bfd_elf_sharable_section_from_bfd_section): Likewise.
(_bfd_elf_sharable_symbol_processing): Likewise.
(_bfd_elf_sharable_common_definition): Likewise.
(_bfd_elf_sharable_common_section_index): Likewise.
(_bfd_elf_sharable_common_section): Likewise.
(_bfd_elf_sharable_merge_symbol): Likewise.
* elf.c (special_sections_g): Add ".gnu.linkonce.shrb" and
".gnu.linkonce.shrd".
(special_sections_s): Add ".sharable_bss" and ".sharable_data".
(get_program_header_size): Handle PT_GNU_SHR segment.
(_bfd_elf_map_sections_to_segments): Likewise.
(assign_file_positions_for_load_sections): Likewise.
* elf32-i386.c (elf_i386_link_hash_table): Add sdynsharablebss
and srelsharablebss fields.
(elf_i386_link_hash_table_create): Initialize sdynsharablebss
and srelsharablebss.
(elf_i386_create_dynamic_sections): Handle sdynsharablebss and
srelsharablebss.
(elf_i386_adjust_dynamic_symbol): Likewise.
(elf_i386_size_dynamic_sections): Likewise.
(elf_i386_finish_dynamic_symbol): Likewise.
(elf_backend_add_symbol_hook): Defined.
(elf_backend_section_from_bfd_section): Likewise.
(elf_backend_symbol_processing): Likewise.
(elf_backend_common_section_index): Likewise.
(elf_backend_common_section): Likewise.
(elf_backend_common_definition): Likewise.
(elf_backend_merge_symbol): Likewise.
* elf64-x86-64.c (elf64_x86_64_link_hash_table): Add
sdynsharablebss and srelsharablebss fields.
(elf64_x86_64_link_hash_table_create): Initialize sdynsharablebss
and srelsharablebss.
(elf64_x86_64_create_dynamic_sections): Handle sdynsharablebss
and srelsharablebss.
(elf64_x86_64_adjust_dynamic_symbol): Likewise.
(elf64_x86_64_size_dynamic_sections): Likewise.
(elf64_x86_64_finish_dynamic_symbol): Likewise.
(elf64_x86_64_add_symbol_hook): Handle sharable symbols.
(elf64_x86_64_elf_section_from_bfd_section): Likewise.
(elf64_x86_64_symbol_processing): Likewise.
(elf64_x86_64_merge_symbol): Likewise.
(elf64_x86_64_common_definition): Handle sharable sections.
(elf64_x86_64_common_section_index): Likewise.
(elf64_x86_64_common_section): Likewise.
* elflink.c (_bfd_elf_create_dynamic_sections): Handle
.dynsharablebss section.
(_bfd_elf_sharable_com_section): New.
(get_sharable_common_section): Likewise.
(_bfd_elf_add_sharable_symbol): Likewise.
(_bfd_elf_sharable_section_from_bfd_section): Likewise.
(_bfd_elf_sharable_symbol_processing): Likewise.
(_bfd_elf_sharable_common_definition): Likewise.
(_bfd_elf_sharable_common_section_index): Likewise.
(_bfd_elf_sharable_common_section): Likewise.
(_bfd_elf_sharable_merge_symbol): Likewise.
* elfxx-ia64.c (elfNN_ia64_add_symbol_hook): Handle sharable
symbols.
(elf_backend_add_symbol_hook): Defined.
(elf_backend_section_from_bfd_section): Likewise.
(elf_backend_symbol_processing): Likewise.
(elf_backend_common_section_index): Likewise.
(elf_backend_common_section): Likewise.
(elf_backend_common_definition): Likewise.
(elf_backend_merge_symbol): Likewise.
binutils/
2007-01-04 H.J. Lu <[EMAIL PROTECTED]>
* readelf.c (dump_relocations): Handle sharable sections.
(get_segment_type): Handle sharable segment.
(get_symbol_index_type): Handle sharable sections.
gas/
2007-01-04 H.J. Lu <[EMAIL PROTECTED]>
* config/obj-elf.c (obj_elf_sharable_common): New.
(elf_pseudo_table): Add "sharable_common".
(obj_elf_change_section): Handle sharable sections.
include/elf/
2007-01-04 H.J. Lu <[EMAIL PROTECTED]>
* common.h (PT_GNU_SHR): New.
(SHF_GNU_SHARABLE): Likewise.
(SHN_GNU_SHARABLE_COMMON): Likewise.
ld/
2007-01-04 H.J. Lu <[EMAIL PROTECTED]>
* emulparams/elf64_ia64.sh (SHARABLE_SECTIONS): Set to yes.
* emulparams/elf_i386.sh (SHARABLE_SECTIONS): Likewise.
* emulparams/elf_x86_64.sh (SHARABLE_SECTIONS): Likewise.
* emultempl/elf32.em: Include "elf-bfd.h".
(gld${EMULATION_NAME}_place_orphan): Don't allow orphaned
sharable sections.
* scripttempl/elf.sc: Support sharable sections.
--- binutils/bfd/elf-bfd.h.shr 2007-01-04 12:24:45.000000000 -0800
+++ binutils/bfd/elf-bfd.h 2007-01-04 12:24:45.000000000 -0800
@@ -1828,6 +1828,28 @@ extern bfd_boolean bfd_elf_link_add_symb
(bfd *, struct bfd_link_info *);
extern bfd_boolean _bfd_elf_add_dynamic_entry
(struct bfd_link_info *, bfd_vma, bfd_vma);
+extern asection _bfd_elf_sharable_com_section;
+extern bfd_boolean _bfd_elf_add_sharable_symbol
+ (bfd *, struct bfd_link_info *, Elf_Internal_Sym *, const char **,
+ flagword *, asection **, bfd_vma *);
+extern bfd_boolean _bfd_elf_sharable_section_from_bfd_section
+ (bfd *, asection *, int *);
+extern void _bfd_elf_sharable_symbol_processing
+ (bfd *, asymbol *);
+extern bfd_boolean _bfd_elf_sharable_common_definition
+ (Elf_Internal_Sym *);
+extern unsigned int _bfd_elf_sharable_common_section_index
+ (asection *);
+extern asection *_bfd_elf_sharable_common_section
+ (asection *);
+extern bfd_boolean _bfd_elf_sharable_merge_symbol
+ (struct bfd_link_info *, struct elf_link_hash_entry **,
+ struct elf_link_hash_entry *, Elf_Internal_Sym *, asection **,
+ bfd_vma *, unsigned int *, bfd_boolean *, bfd_boolean *,
+ bfd_boolean *, bfd_boolean *, bfd_boolean *, bfd_boolean *,
+ bfd_boolean *, bfd_boolean *, bfd *, asection **,
+ bfd_boolean *, bfd_boolean *, bfd_boolean *, bfd_boolean *,
+ bfd *, asection **);
extern bfd_boolean bfd_elf_link_record_dynamic_symbol
(struct bfd_link_info *, struct elf_link_hash_entry *);
--- binutils/bfd/elf.c.shr 2007-01-04 12:24:45.000000000 -0800
+++ binutils/bfd/elf.c 2007-01-04 12:24:45.000000000 -0800
@@ -2329,6 +2329,8 @@ static const struct bfd_elf_special_sect
{ STRING_COMMA_LEN (".gnu.liblist"), 0, SHT_GNU_LIBLIST, SHF_ALLOC },
{ STRING_COMMA_LEN (".gnu.conflict"), 0, SHT_RELA, SHF_ALLOC },
{ STRING_COMMA_LEN (".gnu.hash"), 0, SHT_GNU_HASH, SHF_ALLOC },
+ { STRING_COMMA_LEN (".gnu.linkonce.shrb"), -2, SHT_NOBITS, SHF_ALLOC +
SHF_WRITE + SHF_GNU_SHARABLE},
+ { STRING_COMMA_LEN (".gnu.linkonce.shrd"), -2, SHT_PROGBITS, SHF_ALLOC +
SHF_WRITE + SHF_GNU_SHARABLE},
{ NULL, 0, 0, 0, 0 }
};
@@ -2383,6 +2385,8 @@ static const struct bfd_elf_special_sect
/* See struct bfd_elf_special_section declaration for the semantics of
this special case where .prefix_length != strlen (.prefix). */
{ ".stabstr", 5, 3, SHT_STRTAB, 0 },
+ { STRING_COMMA_LEN (".sharable_bss"), -2, SHT_NOBITS, SHF_ALLOC + SHF_WRITE
+ SHF_GNU_SHARABLE},
+ { STRING_COMMA_LEN (".sharable_data"), -2, SHT_PROGBITS, SHF_ALLOC +
SHF_WRITE + SHF_GNU_SHARABLE},
{ NULL, 0, 0, 0, 0 }
};
@@ -3671,6 +3675,32 @@ get_program_header_size (bfd *abfd, stru
}
}
+ /* Check to see if we need a PT_GNU_SHR segment for sharable data
+ sections. */
+ for (s = abfd->sections; s != NULL; s = s->next)
+ {
+ if ((elf_section_flags (s) & SHF_GNU_SHARABLE) != 0
+ && elf_section_type (s) == SHT_PROGBITS)
+ {
+ /* We need a PT_GNU_SHR segment. */
+ ++segs;
+ break;
+ }
+ }
+
+ /* Check to see if we need a PT_GNU_SHR segment for sharable bss
+ sections. */
+ for (s = abfd->sections; s != NULL; s = s->next)
+ {
+ if ((elf_section_flags (s) & SHF_GNU_SHARABLE) != 0
+ && elf_section_type (s) == SHT_NOBITS)
+ {
+ /* We need a PT_GNU_SHR segment. */
+ ++segs;
+ break;
+ }
+ }
+
/* Let the backend count up any program headers it might need. */
bed = get_elf_backend_data (abfd);
if (bed->elf_backend_additional_program_headers)
@@ -3811,6 +3841,8 @@ _bfd_elf_map_sections_to_segments (bfd *
bfd_boolean phdr_in_segment = TRUE;
bfd_boolean writable;
int tls_count = 0;
+ int sharable_data_count = 0, sharable_bss_count = 0;
+ asection *first_sharable_data = NULL, *first_sharable_bss = NULL;
asection *first_tls = NULL;
asection *dynsec, *eh_frame_hdr;
bfd_size_type amt;
@@ -4056,6 +4088,22 @@ _bfd_elf_map_sections_to_segments (bfd *
first_tls = s;
tls_count++;
}
+ if (elf_section_flags (s) & SHF_GNU_SHARABLE)
+ {
+ if (elf_section_type (s) == SHT_PROGBITS)
+ {
+ if (! sharable_data_count)
+ first_sharable_data = s;
+ sharable_data_count++;
+ }
+ else
+ {
+ BFD_ASSERT (elf_section_type (s) == SHT_NOBITS);
+ if (! sharable_bss_count)
+ first_sharable_bss = s;
+ sharable_bss_count++;
+ }
+ }
}
/* If there are any SHF_TLS output sections, add PT_TLS segment. */
@@ -4085,6 +4133,60 @@ _bfd_elf_map_sections_to_segments (bfd *
pm = &m->next;
}
+ /* If there are any output SHF_GNU_SHARABLE data sections, add a
+ PT_GNU_SHR segment. */
+ if (sharable_data_count > 0)
+ {
+ int i;
+
+ amt = sizeof (struct elf_segment_map);
+ amt += (sharable_data_count - 1) * sizeof (asection *);
+ m = bfd_zalloc (abfd, amt);
+ if (m == NULL)
+ goto error_return;
+ m->next = NULL;
+ m->p_type = PT_GNU_SHR;
+ m->count = sharable_data_count;
+ /* Mandated PF_R. */
+ m->p_flags = PF_R;
+ m->p_flags_valid = 1;
+ for (i = 0; i < sharable_data_count; ++i)
+ {
+ m->sections[i] = first_sharable_data;
+ first_sharable_data = first_sharable_data->next;
+ }
+
+ *pm = m;
+ pm = &m->next;
+ }
+
+ /* If there are any output SHF_GNU_SHARABLE bss sections, add a
+ PT_GNU_SHR segment. */
+ if (sharable_bss_count > 0)
+ {
+ int i;
+
+ amt = sizeof (struct elf_segment_map);
+ amt += (sharable_bss_count - 1) * sizeof (asection *);
+ m = bfd_zalloc (abfd, amt);
+ if (m == NULL)
+ goto error_return;
+ m->next = NULL;
+ m->p_type = PT_GNU_SHR;
+ m->count = sharable_bss_count;
+ /* Mandated PF_R. */
+ m->p_flags = PF_R;
+ m->p_flags_valid = 1;
+ for (i = 0; i < sharable_bss_count; ++i)
+ {
+ m->sections[i] = first_sharable_bss;
+ first_sharable_bss = first_sharable_bss->next;
+ }
+
+ *pm = m;
+ pm = &m->next;
+ }
+
/* If there is a .eh_frame_hdr section, throw in a PT_GNU_EH_FRAME
segment. */
eh_frame_hdr = elf_tdata (abfd)->eh_frame_hdr;
@@ -4505,6 +4607,7 @@ assign_file_positions_for_load_sections
align = (bfd_size_type) 1 << bfd_get_section_alignment (abfd, sec);
if (p->p_type == PT_LOAD
+ || p->p_type == PT_GNU_SHR
|| p->p_type == PT_TLS)
{
bfd_signed_vma adjust;
--- binutils/bfd/elf32-i386.c.shr 2007-01-04 12:24:45.000000000 -0800
+++ binutils/bfd/elf32-i386.c 2007-01-04 12:24:45.000000000 -0800
@@ -646,6 +646,8 @@ struct elf_i386_link_hash_table
asection *srelplt;
asection *sdynbss;
asection *srelbss;
+ asection *sdynsharablebss;
+ asection *srelsharablebss;
/* The (unloaded but important) .rel.plt.unloaded section on VxWorks. */
asection *srelplt2;
@@ -738,6 +740,8 @@ elf_i386_link_hash_table_create (bfd *ab
ret->srelplt = NULL;
ret->sdynbss = NULL;
ret->srelbss = NULL;
+ ret->sdynsharablebss = NULL;
+ ret->srelsharablebss = NULL;
ret->tls_ldm_got.refcount = 0;
ret->next_tls_desc_index = 0;
ret->sgotplt_jump_table_size = 0;
@@ -798,10 +802,19 @@ elf_i386_create_dynamic_sections (bfd *d
htab->srelplt = bfd_get_section_by_name (dynobj, ".rel.plt");
htab->sdynbss = bfd_get_section_by_name (dynobj, ".dynbss");
if (!info->shared)
- htab->srelbss = bfd_get_section_by_name (dynobj, ".rel.bss");
+ {
+ htab->srelbss = bfd_get_section_by_name (dynobj, ".rel.bss");
+ htab->sdynsharablebss
+ = bfd_get_section_by_name (dynobj, ".dynsharablebss");
+ htab->srelsharablebss
+ = bfd_get_section_by_name (dynobj, ".rel.sharable_bss");
+ }
if (!htab->splt || !htab->srelplt || !htab->sdynbss
- || (!info->shared && !htab->srelbss))
+ || (!info->shared
+ && (!htab->srelbss
+ || !htab->sdynsharablebss
+ || !htab->srelsharablebss)))
abort ();
if (htab->is_vxworks
@@ -1516,12 +1529,20 @@ elf_i386_adjust_dynamic_symbol (struct b
both the dynamic object and the regular object will refer to the
same memory location for the variable. */
+ s = htab->sdynbss;
+
/* We must generate a R_386_COPY reloc to tell the dynamic linker to
copy the initial value out of the dynamic object and into the
runtime process image. */
if ((h->root.u.def.section->flags & SEC_ALLOC) != 0)
{
- htab->srelbss->size += sizeof (Elf32_External_Rel);
+ if (elf_section_flags (h->root.u.def.section) & SHF_GNU_SHARABLE)
+ {
+ htab->srelsharablebss->size += sizeof (Elf32_External_Rel);
+ s = htab->sdynsharablebss;
+ }
+ else
+ htab->srelbss->size += sizeof (Elf32_External_Rel);
h->needs_copy = 1;
}
@@ -1532,7 +1553,6 @@ elf_i386_adjust_dynamic_symbol (struct b
power_of_two = 3;
/* Apply the required alignment. */
- s = htab->sdynbss;
s->size = BFD_ALIGN (s->size, (bfd_size_type) (1 << power_of_two));
if (power_of_two > bfd_get_section_alignment (htab->elf.dynobj, s))
{
@@ -2000,7 +2020,8 @@ elf_i386_size_dynamic_sections (bfd *out
if (s == htab->splt
|| s == htab->sgot
|| s == htab->sgotplt
- || s == htab->sdynbss)
+ || s == htab->sdynbss
+ || s == htab->sdynsharablebss)
{
/* Strip this section if we don't need it; see the
comment below. */
@@ -3571,21 +3592,27 @@ elf_i386_finish_dynamic_symbol (bfd *out
{
Elf_Internal_Rela rel;
bfd_byte *loc;
+ asection *s;
+
+ if (h->root.u.def.section == htab->sdynsharablebss)
+ s = htab->srelsharablebss;
+ else
+ s = htab->srelbss;
/* This symbol needs a copy reloc. Set it up. */
if (h->dynindx == -1
|| (h->root.type != bfd_link_hash_defined
&& h->root.type != bfd_link_hash_defweak)
- || htab->srelbss == NULL)
+ || s == NULL)
abort ();
rel.r_offset = (h->root.u.def.value
+ h->root.u.def.section->output_section->vma
+ h->root.u.def.section->output_offset);
rel.r_info = ELF32_R_INFO (h->dynindx, R_386_COPY);
- loc = htab->srelbss->contents;
- loc += htab->srelbss->reloc_count++ * sizeof (Elf32_External_Rel);
+ loc = s->contents;
+ loc += s->reloc_count++ * sizeof (Elf32_External_Rel);
bfd_elf32_swap_reloc_out (output_bfd, &rel, loc);
}
@@ -3872,6 +3899,21 @@ elf_i386_hash_symbol (struct elf_link_ha
#define elf_backend_plt_sym_val elf_i386_plt_sym_val
#define elf_backend_hash_symbol elf_i386_hash_symbol
+#define elf_backend_add_symbol_hook \
+ _bfd_elf_add_sharable_symbol
+#define elf_backend_section_from_bfd_section \
+ _bfd_elf_sharable_section_from_bfd_section
+#define elf_backend_symbol_processing \
+ _bfd_elf_sharable_symbol_processing
+#define elf_backend_common_section_index \
+ _bfd_elf_sharable_common_section_index
+#define elf_backend_common_section \
+ _bfd_elf_sharable_common_section
+#define elf_backend_common_definition \
+ _bfd_elf_sharable_common_definition
+#define elf_backend_merge_symbol \
+ _bfd_elf_sharable_merge_symbol
+
#include "elf32-target.h"
/* FreeBSD support. */
--- binutils/bfd/elf64-x86-64.c.shr 2007-01-04 12:24:45.000000000 -0800
+++ binutils/bfd/elf64-x86-64.c 2007-01-04 12:24:45.000000000 -0800
@@ -452,6 +452,8 @@ struct elf64_x86_64_link_hash_table
asection *srelplt;
asection *sdynbss;
asection *srelbss;
+ asection *sdynsharablebss;
+ asection *srelsharablebss;
/* The offset into splt of the PLT entry for the TLS descriptor
resolver. Special values are 0, if not necessary (or not found
@@ -539,6 +541,8 @@ elf64_x86_64_link_hash_table_create (bfd
ret->srelplt = NULL;
ret->sdynbss = NULL;
ret->srelbss = NULL;
+ ret->sdynsharablebss = NULL;
+ ret->srelsharablebss = NULL;
ret->sym_sec.abfd = NULL;
ret->tlsdesc_plt = 0;
ret->tlsdesc_got = 0;
@@ -597,10 +601,19 @@ elf64_x86_64_create_dynamic_sections (bf
htab->srelplt = bfd_get_section_by_name (dynobj, ".rela.plt");
htab->sdynbss = bfd_get_section_by_name (dynobj, ".dynbss");
if (!info->shared)
- htab->srelbss = bfd_get_section_by_name (dynobj, ".rela.bss");
+ {
+ htab->srelbss = bfd_get_section_by_name (dynobj, ".rela.bss");
+ htab->sdynsharablebss
+ = bfd_get_section_by_name (dynobj, ".dynsharablebss");
+ htab->srelsharablebss
+ = bfd_get_section_by_name (dynobj, ".rela.sharable_bss");
+ }
if (!htab->splt || !htab->srelplt || !htab->sdynbss
- || (!info->shared && !htab->srelbss))
+ || (!info->shared
+ && (!htab->srelbss
+ || !htab->sdynsharablebss
+ || !htab->srelsharablebss)))
abort ();
return TRUE;
@@ -1379,12 +1392,20 @@ elf64_x86_64_adjust_dynamic_symbol (stru
htab = elf64_x86_64_hash_table (info);
+ s = htab->sdynbss;
+
/* We must generate a R_X86_64_COPY reloc to tell the dynamic linker
to copy the initial value out of the dynamic object and into the
runtime process image. */
if ((h->root.u.def.section->flags & SEC_ALLOC) != 0)
{
- htab->srelbss->size += sizeof (Elf64_External_Rela);
+ if (elf_section_flags (h->root.u.def.section) & SHF_GNU_SHARABLE)
+ {
+ htab->srelsharablebss->size += sizeof (Elf64_External_Rela);
+ s = htab->sdynsharablebss;
+ }
+ else
+ htab->srelbss->size += sizeof (Elf64_External_Rela);
h->needs_copy = 1;
}
@@ -1398,7 +1419,6 @@ elf64_x86_64_adjust_dynamic_symbol (stru
power_of_two = 4;
/* Apply the required alignment. */
- s = htab->sdynbss;
s->size = BFD_ALIGN (s->size, (bfd_size_type) (1 << power_of_two));
if (power_of_two > bfd_get_section_alignment (htab->elf.dynobj, s))
{
@@ -1860,7 +1880,8 @@ elf64_x86_64_size_dynamic_sections (bfd
if (s == htab->splt
|| s == htab->sgot
|| s == htab->sgotplt
- || s == htab->sdynbss)
+ || s == htab->sdynbss
+ || s == htab->sdynsharablebss)
{
/* Strip this section if we don't need it; see the
comment below. */
@@ -3196,13 +3217,19 @@ elf64_x86_64_finish_dynamic_symbol (bfd
{
Elf_Internal_Rela rela;
bfd_byte *loc;
+ asection *s;
+
+ if (h->root.u.def.section == htab->sdynsharablebss)
+ s = htab->srelsharablebss;
+ else
+ s = htab->srelbss;
/* This symbol needs a copy reloc. Set it up. */
if (h->dynindx == -1
|| (h->root.type != bfd_link_hash_defined
&& h->root.type != bfd_link_hash_defweak)
- || htab->srelbss == NULL)
+ || s == NULL)
abort ();
rela.r_offset = (h->root.u.def.value
@@ -3210,8 +3237,8 @@ elf64_x86_64_finish_dynamic_symbol (bfd
+ h->root.u.def.section->output_offset);
rela.r_info = ELF64_R_INFO (h->dynindx, R_X86_64_COPY);
rela.r_addend = 0;
- loc = htab->srelbss->contents;
- loc += htab->srelbss->reloc_count++ * sizeof (Elf64_External_Rela);
+ loc = s->contents;
+ loc += s->reloc_count++ * sizeof (Elf64_External_Rela);
bfd_elf64_swap_reloca_out (output_bfd, &rela, loc);
}
@@ -3475,9 +3502,12 @@ elf64_x86_64_add_symbol_hook (bfd *abfd,
}
*secp = lcomm;
*valp = sym->st_size;
+ return TRUE;
break;
}
- return TRUE;
+
+ return _bfd_elf_add_sharable_symbol (abfd, info, sym, namep, flagsp,
+ secp, valp);
}
@@ -3493,7 +3523,7 @@ elf64_x86_64_elf_section_from_bfd_sectio
*index = SHN_X86_64_LCOMMON;
return TRUE;
}
- return FALSE;
+ return _bfd_elf_sharable_section_from_bfd_section (abfd, sec, index);
}
/* Process a symbol. */
@@ -3511,22 +3541,26 @@ elf64_x86_64_symbol_processing (bfd *abf
asym->value = elfsym->internal_elf_sym.st_size;
/* Common symbol doesn't set BSF_GLOBAL. */
asym->flags &= ~BSF_GLOBAL;
+ return;
break;
}
+
+ _bfd_elf_sharable_symbol_processing (abfd, asym);
}
static bfd_boolean
elf64_x86_64_common_definition (Elf_Internal_Sym *sym)
{
return (sym->st_shndx == SHN_COMMON
- || sym->st_shndx == SHN_X86_64_LCOMMON);
+ || sym->st_shndx == SHN_X86_64_LCOMMON
+ || _bfd_elf_sharable_common_definition (sym));
}
static unsigned int
elf64_x86_64_common_section_index (asection *sec)
{
if ((elf_section_flags (sec) & SHF_X86_64_LARGE) == 0)
- return SHN_COMMON;
+ return _bfd_elf_sharable_common_section_index (sec);
else
return SHN_X86_64_LCOMMON;
}
@@ -3535,7 +3569,7 @@ static asection *
elf64_x86_64_common_section (asection *sec)
{
if ((elf_section_flags (sec) & SHF_X86_64_LARGE) == 0)
- return bfd_com_section_ptr;
+ return _bfd_elf_sharable_common_section (sec);
else
return &_bfd_elf_large_com_section;
}
@@ -3572,7 +3606,8 @@ elf64_x86_64_merge_symbol (struct bfd_li
&& h->root.type == bfd_link_hash_common
&& !*newdyn
&& bfd_is_com_section (*sec)
- && *oldsec != *sec)
+ && *oldsec != *sec
+ && _bfd_elf_sharable_common_section_index (*oldsec) == SHN_COMMON)
{
if (sym->st_shndx == SHN_COMMON
&& (elf_section_flags (*oldsec) & SHF_X86_64_LARGE) != 0)
@@ -3580,13 +3615,26 @@ elf64_x86_64_merge_symbol (struct bfd_li
h->root.u.c.p->section
= bfd_make_section_old_way (oldbfd, "COMMON");
h->root.u.c.p->section->flags = SEC_ALLOC;
+ return TRUE;
}
else if (sym->st_shndx == SHN_X86_64_LCOMMON
&& (elf_section_flags (*oldsec) & SHF_X86_64_LARGE) == 0)
- *psec = *sec = bfd_com_section_ptr;
+ {
+ *psec = *sec = bfd_com_section_ptr;
+ return TRUE;
+ }
}
- return TRUE;
+ return _bfd_elf_sharable_merge_symbol (info, sym_hash, h, sym,
+ psec, pvalue, pold_alignment,
+ skip, override,
+ type_change_ok, size_change_ok,
+ newdyn, newdef,
+ newdyncommon, newweak,
+ abfd, sec,
+ olddyn, olddef,
+ olddyncommon, oldweak,
+ oldbfd, oldsec);
}
static int
--- binutils/bfd/elflink.c.shr 2007-01-04 12:24:45.000000000 -0800
+++ binutils/bfd/elflink.c 2007-01-04 12:24:45.000000000 -0800
@@ -352,6 +352,22 @@ _bfd_elf_create_dynamic_sections (bfd *a
if (s == NULL
|| ! bfd_set_section_alignment (abfd, s, bed->s->log_file_align))
return FALSE;
+
+ s = bfd_make_section (abfd, ".dynsharablebss");
+ if (s == NULL
+ || ! bfd_set_section_flags (abfd, s,
+ (SEC_ALLOC
+ | SEC_LINKER_CREATED)))
+ return FALSE;
+
+ s = bfd_make_section (abfd,
+ (bed->default_use_rela_p
+ ? ".rela.sharable_bss"
+ : ".rel.sharable_bss"));
+ if (s == NULL
+ || ! bfd_set_section_flags (abfd, s, flags | SEC_READONLY)
+ || ! bfd_set_section_alignment (abfd, s, bed->s->log_file_align))
+ return FALSE;
}
}
@@ -10581,3 +10597,219 @@ _bfd_elf_common_section (asection *sec A
{
return bfd_com_section_ptr;
}
+
+asection _bfd_elf_sharable_com_section
+ = BFD_FAKE_SECTION (_bfd_elf_sharable_com_section, SEC_IS_COMMON,
+ NULL, "SHARABLE_COMMON", 0);
+
+static asection *
+get_sharable_common_section (bfd *abfd)
+{
+ asection *scomm = bfd_get_section_by_name (abfd, "SHARABLE_COMMON");
+
+ if (scomm == NULL)
+ {
+ scomm = bfd_make_section_with_flags (abfd,
+ "SHARABLE_COMMON",
+ (SEC_ALLOC
+ | SEC_IS_COMMON
+ | SEC_LINKER_CREATED));
+ if (scomm == NULL)
+ return scomm;
+ elf_section_flags (scomm) |= SHF_GNU_SHARABLE;
+ }
+
+ return scomm;
+}
+
+bfd_boolean
+_bfd_elf_add_sharable_symbol (bfd *abfd ATTRIBUTE_UNUSED,
+ struct bfd_link_info *info ATTRIBUTE_UNUSED,
+ Elf_Internal_Sym *sym,
+ const char **namep ATTRIBUTE_UNUSED,
+ flagword *flagsp ATTRIBUTE_UNUSED,
+ asection **secp,
+ bfd_vma *valp)
+{
+ asection *scomm;
+
+ switch (sym->st_shndx)
+ {
+ case SHN_GNU_SHARABLE_COMMON:
+ scomm = get_sharable_common_section (abfd);
+ if (scomm == NULL)
+ return FALSE;
+ *secp = scomm;
+ *valp = sym->st_size;
+ break;
+ }
+ return TRUE;
+}
+
+bfd_boolean
+_bfd_elf_sharable_section_from_bfd_section
+ (bfd *abfd ATTRIBUTE_UNUSED, asection *sec, int *index)
+{
+ if (sec == &_bfd_elf_sharable_com_section)
+ {
+ *index = SHN_GNU_SHARABLE_COMMON;
+ return TRUE;
+ }
+ return FALSE;
+}
+
+void
+_bfd_elf_sharable_symbol_processing (bfd *abfd ATTRIBUTE_UNUSED,
+ asymbol *asym)
+{
+ elf_symbol_type *elfsym = (elf_symbol_type *) asym;
+
+ switch (elfsym->internal_elf_sym.st_shndx)
+ {
+ case SHN_GNU_SHARABLE_COMMON:
+ asym->section = &_bfd_elf_sharable_com_section;
+ asym->value = elfsym->internal_elf_sym.st_size;
+ asym->flags &= ~BSF_GLOBAL;
+ break;
+ }
+}
+
+bfd_boolean
+_bfd_elf_sharable_common_definition (Elf_Internal_Sym *sym)
+{
+ return (sym->st_shndx == SHN_COMMON
+ || sym->st_shndx == SHN_GNU_SHARABLE_COMMON);
+}
+
+unsigned int
+_bfd_elf_sharable_common_section_index (asection *sec)
+{
+ if ((elf_section_flags (sec) & SHF_GNU_SHARABLE) == 0)
+ return SHN_COMMON;
+ else
+ return SHN_GNU_SHARABLE_COMMON;
+}
+
+asection *
+_bfd_elf_sharable_common_section (asection *sec)
+{
+ if ((elf_section_flags (sec) & SHF_GNU_SHARABLE) == 0)
+ return bfd_com_section_ptr;
+ else
+ return &_bfd_elf_sharable_com_section;
+}
+
+bfd_boolean
+_bfd_elf_sharable_merge_symbol
+ (struct bfd_link_info *info ATTRIBUTE_UNUSED,
+ struct elf_link_hash_entry **sym_hash ATTRIBUTE_UNUSED,
+ struct elf_link_hash_entry *h,
+ Elf_Internal_Sym *sym ATTRIBUTE_UNUSED,
+ asection **psec,
+ bfd_vma *pvalue ATTRIBUTE_UNUSED,
+ unsigned int *pold_alignment ATTRIBUTE_UNUSED,
+ bfd_boolean *skip ATTRIBUTE_UNUSED,
+ bfd_boolean *override ATTRIBUTE_UNUSED,
+ bfd_boolean *type_change_ok ATTRIBUTE_UNUSED,
+ bfd_boolean *size_change_ok ATTRIBUTE_UNUSED,
+ bfd_boolean *newdef ATTRIBUTE_UNUSED,
+ bfd_boolean *newdyn,
+ bfd_boolean *newdyncommon ATTRIBUTE_UNUSED,
+ bfd_boolean *newweak ATTRIBUTE_UNUSED,
+ bfd *abfd,
+ asection **sec,
+ bfd_boolean *olddef ATTRIBUTE_UNUSED,
+ bfd_boolean *olddyn,
+ bfd_boolean *olddyncommon ATTRIBUTE_UNUSED,
+ bfd_boolean *oldweak ATTRIBUTE_UNUSED,
+ bfd *oldbfd,
+ asection **oldsec)
+{
+ /* Check sharable symbol. If one is undefined, it is OK. */
+ if (*oldsec && !bfd_is_und_section (*sec))
+ {
+ bfd_boolean sharable, oldsharable;
+
+ sharable = (elf_section_data (*sec)
+ && (elf_section_flags (*sec) & SHF_GNU_SHARABLE));
+ oldsharable = (elf_section_data (*oldsec)
+ && (elf_section_flags (*oldsec)
+ & SHF_GNU_SHARABLE));
+
+ if (sharable != oldsharable)
+ {
+ bfd *nsbfd, *sbfd;
+ asection *nssec, *ssec;
+ bfd_boolean nsdyn, sdyn, nsdef, sdef;
+
+ if (oldsharable)
+ {
+ sbfd = oldbfd;
+ nsbfd = abfd;
+ ssec = *oldsec;
+ nssec = *sec;
+ sdyn = *olddyn;
+ nsdyn = *newdyn;
+ sdef = *olddef;
+ nsdef = *newdef;
+ }
+ else
+ {
+ sbfd = abfd;
+ nsbfd = oldbfd;
+ ssec = *sec;
+ nssec = *oldsec;
+ sdyn = *newdyn;
+ nsdyn = *olddyn;
+ sdef = *newdef;
+ nsdef = *olddef;
+ }
+
+ if (sdef && !sdyn)
+ {
+ /* If the sharable definition comes from a relocatable
+ file, it will override the non-sharable one in DSO. */
+ return TRUE;
+ }
+ else if (!nsdef
+ && !nsdyn
+ && (h->root.type == bfd_link_hash_common
+ || bfd_is_com_section (nssec)))
+ {
+ asection *scomm;
+
+ /* When the non-sharable common symbol in a relocatable
+ file, we can turn it into sharable. If the sharable
+ symbol isn't common, the non-sharable common symbol
+ will be overidden. We only need to handle the
+ sharable common symbol and the non-sharable common
+ symbol. We just turn the non-sharable common symbol
+ into the sharable one. */
+ if (sym->st_shndx == SHN_GNU_SHARABLE_COMMON)
+ {
+ scomm = get_sharable_common_section (oldbfd);
+ if (scomm == NULL)
+ return FALSE;
+ h->root.u.c.p->section = scomm;
+ }
+ else
+ {
+ scomm = get_sharable_common_section (abfd);
+ if (scomm == NULL)
+ return FALSE;
+ *psec = *sec = scomm;
+ }
+
+ return TRUE;
+ }
+
+ (*_bfd_error_handler)
+ (_("%s: sharable symbol in %B section %A mismatches non-shrable
symbol in %B section %A"),
+ sbfd, ssec, nsbfd, nssec, h->root.root.string);
+ bfd_set_error (bfd_error_bad_value);
+ return FALSE;
+ }
+ }
+
+ return TRUE;
+}
--- binutils/bfd/elfxx-ia64.c.shr 2007-01-04 12:24:45.000000000 -0800
+++ binutils/bfd/elfxx-ia64.c 2007-01-04 12:24:45.000000000 -0800
@@ -1620,7 +1620,8 @@ elfNN_ia64_add_symbol_hook (abfd, info,
*valp = sym->st_size;
}
- return TRUE;
+ return _bfd_elf_add_sharable_symbol (abfd, info, sym, namep, flagsp,
+ secp, valp);
}
/* Return the number of additional phdrs we will need. */
@@ -5802,6 +5803,19 @@ elfNN_hpux_backend_symbol_processing (bf
#define elf_backend_rela_normal 1
#define elf_backend_special_sections elfNN_ia64_special_sections
+#define elf_backend_section_from_bfd_section \
+ _bfd_elf_sharable_section_from_bfd_section
+#define elf_backend_symbol_processing \
+ _bfd_elf_sharable_symbol_processing
+#define elf_backend_common_section_index \
+ _bfd_elf_sharable_common_section_index
+#define elf_backend_common_section \
+ _bfd_elf_sharable_common_section
+#define elf_backend_common_definition \
+ _bfd_elf_sharable_common_definition
+#define elf_backend_merge_symbol \
+ _bfd_elf_sharable_merge_symbol
+
/* FIXME: PR 290: The Intel C compiler generates SHT_IA_64_UNWIND with
SHF_LINK_ORDER. But it doesn't set the sh_link or sh_info fields.
We don't want to flood users with so many error messages. We turn
--- binutils/binutils/readelf.c.shr 2006-12-27 07:30:41.000000000 -0800
+++ binutils/binutils/readelf.c 2007-01-04 12:24:45.000000000 -0800
@@ -1238,6 +1238,8 @@ dump_relocations (FILE *file,
sec_name = "ABS";
else if (psym->st_shndx == SHN_COMMON)
sec_name = "COMMON";
+ else if (psym->st_shndx == SHN_GNU_SHARABLE_COMMON)
+ sec_name = "GNU_SHARABLE_COMMON";
else if (elf_header.e_machine == EM_MIPS
&& psym->st_shndx == SHN_MIPS_SCOMMON)
sec_name = "SCOMMON";
@@ -2436,6 +2438,7 @@ get_segment_type (unsigned long p_type)
case PT_SHLIB: return "SHLIB";
case PT_PHDR: return "PHDR";
case PT_TLS: return "TLS";
+ case PT_GNU_SHR: return "GNU_SHR";
case PT_GNU_EH_FRAME:
return "GNU_EH_FRAME";
@@ -6935,6 +6938,8 @@ get_symbol_index_type (unsigned int type
case SHN_UNDEF: return "UND";
case SHN_ABS: return "ABS";
case SHN_COMMON: return "COM";
+ case SHN_GNU_SHARABLE_COMMON:
+ return "GNU_SHARABLE_COM";
default:
if (type == SHN_IA_64_ANSI_COMMON
&& elf_header.e_machine == EM_IA_64
--- binutils/gas/config/obj-elf.c.shr 2006-12-05 11:27:59.000000000 -0800
+++ binutils/gas/config/obj-elf.c 2007-01-04 12:24:45.000000000 -0800
@@ -68,6 +68,7 @@ static void obj_elf_symver (int);
static void obj_elf_subsection (int);
static void obj_elf_popsection (int);
static void obj_elf_tls_common (int);
+static void obj_elf_sharable_common (int);
static void obj_elf_lcomm (int);
static void obj_elf_struct (int);
@@ -125,6 +126,8 @@ static const pseudo_typeS elf_pseudo_tab
{"tls_common", obj_elf_tls_common, 0},
+ {"sharable_common", obj_elf_sharable_common, 0},
+
/* End sentinel. */
{NULL, NULL, 0},
};
@@ -369,6 +372,39 @@ obj_elf_tls_common (int ignore ATTRIBUTE
}
static void
+obj_elf_sharable_common (int ignore ATTRIBUTE_UNUSED)
+{
+ static segT sharable_bss_section;
+ asection *saved_com_section_ptr = elf_com_section_ptr;
+ asection *saved_bss_section = bss_section;
+
+ if (sharable_bss_section == NULL)
+ {
+ flagword applicable;
+ segT seg = now_seg;
+ subsegT subseg = now_subseg;
+
+ /* The .sharable_bss section is for local .sharable_common
+ symbols. */
+ sharable_bss_section = subseg_new (".sharable_bss", 0);
+ applicable = bfd_applicable_section_flags (stdoutput);
+ bfd_set_section_flags (stdoutput, sharable_bss_section,
+ applicable & SEC_ALLOC);
+ seg_info (sharable_bss_section)->bss = 1;
+
+ subseg_set (seg, subseg);
+ }
+
+ elf_com_section_ptr = &_bfd_elf_sharable_com_section;
+ bss_section = sharable_bss_section;
+
+ s_comm_internal (0, elf_common_parse);
+
+ elf_com_section_ptr = saved_com_section_ptr;
+ bss_section = saved_bss_section;
+}
+
+static void
obj_elf_lcomm (int ignore ATTRIBUTE_UNUSED)
{
symbolS *symbolP = s_comm_internal (0, s_lcomm_internal);
@@ -582,11 +618,17 @@ obj_elf_change_section (const char *name
.section .lbss,"aw",@progbits
+ "@progbits" is incorrect. Also for sharable bss
+ sections, gcc, as of 2005-07-06, will emit
+
+ .section .sharable_bss,"aw",@progbits
+
"@progbits" is incorrect. */
#ifdef TC_I386
&& (bed->s->arch_size != 64
|| !(ssect->attr & SHF_X86_64_LARGE))
#endif
+ && !(ssect->attr & SHF_GNU_SHARABLE)
&& ssect->type != SHT_INIT_ARRAY
&& ssect->type != SHT_FINI_ARRAY
&& ssect->type != SHT_PREINIT_ARRAY)
--- binutils/include/elf/common.h.shr 2006-10-24 23:49:18.000000000 -0700
+++ binutils/include/elf/common.h 2007-01-04 12:25:50.000000000 -0800
@@ -306,6 +306,7 @@
#define PT_SUNW_EH_FRAME PT_GNU_EH_FRAME /* Solaris uses the same value */
#define PT_GNU_STACK (PT_LOOS + 0x474e551) /* Stack flags */
#define PT_GNU_RELRO (PT_LOOS + 0x474e552) /* Read-only after relocation */
+#define PT_GNU_SHR (PT_LOOS + 0x474e554) /* Sharable segment */
/* Program segment permissions, in program header p_flags field. */
@@ -377,6 +378,8 @@
#define SHF_MASKOS 0x0FF00000 /* New value, Oct 4, 1999 Draft */
#define SHF_MASKPROC 0xF0000000 /* Processor-specific semantics */
+#define SHF_GNU_SHARABLE 0x01000000 /* sharable section */
+
/* Values of note segment descriptor types for core files. */
#define NT_PRSTATUS 1 /* Contains copy of prstatus struct */
@@ -495,6 +498,9 @@
#define SHN_HIRESERVE 0xFFFF /* End range of reserved indices */
#define SHN_BAD ((unsigned) -1) /* Used internally by bfd */
+/* Associated symbol is in common sharable */
+#define SHN_GNU_SHARABLE_COMMON (SHN_LOOS + 10)
+
/* The following constants control how a symbol may be accessed once it has
become part of an executable or shared library. */
--- binutils/ld/emulparams/elf64_ia64.sh.shr 2006-05-30 09:45:32.000000000
-0700
+++ binutils/ld/emulparams/elf64_ia64.sh 2007-01-04 12:24:45.000000000
-0800
@@ -37,3 +37,4 @@ OTHER_READONLY_SECTIONS="${OTHER_READONL
# .dtors. They have to be next to .sbss/.sbss2/.sdata/.sdata2.
SMALL_DATA_CTOR=" "
SMALL_DATA_DTOR=" "
+SHARABLE_SECTIONS=yes
--- binutils/ld/emulparams/elf_i386.sh.shr 2006-05-30 09:45:32.000000000
-0700
+++ binutils/ld/emulparams/elf_i386.sh 2007-01-04 12:24:45.000000000 -0800
@@ -12,3 +12,4 @@ GENERATE_SHLIB_SCRIPT=yes
GENERATE_PIE_SCRIPT=yes
NO_SMALL_DATA=yes
SEPARATE_GOTPLT=12
+SHARABLE_SECTIONS=yes
--- binutils/ld/emulparams/elf_x86_64.sh.shr 2006-10-18 09:24:01.000000000
-0700
+++ binutils/ld/emulparams/elf_x86_64.sh 2007-01-04 12:24:45.000000000
-0800
@@ -14,6 +14,7 @@ GENERATE_PIE_SCRIPT=yes
NO_SMALL_DATA=yes
LARGE_SECTIONS=yes
SEPARATE_GOTPLT=24
+SHARABLE_SECTIONS=yes
if [ "x${host}" = "x${target}" ]; then
case " $EMULATION_LIBPATH " in
--- binutils/ld/emultempl/elf32.em.shr 2006-12-05 11:28:02.000000000 -0800
+++ binutils/ld/emultempl/elf32.em 2007-01-04 12:24:45.000000000 -0800
@@ -55,6 +55,8 @@ Foundation, Inc., 51 Franklin Street - F
#include "elf/common.h"
#include "elf-bfd.h"
+#include "elf-bfd.h"
+
/* Declare functions used by various EXTRA_EM_FILEs. */
static void gld${EMULATION_NAME}_before_parse (void);
static void gld${EMULATION_NAME}_after_open (void);
@@ -1456,6 +1458,12 @@ gld${EMULATION_NAME}_place_orphan (asect
secname = bfd_get_section_name (s->owner, s);
+ /* Orphaned sharable sections won't have correct page
+ requirements. */
+ if (elf_section_flags (s) & SHF_GNU_SHARABLE)
+ einfo ("%F%P: unable to place orphaned sharable section %A (%B)\n",
+ s, s->owner);
+
if (! link_info.relocatable
&& link_info.combreloc
&& (s->flags & SEC_ALLOC))
--- binutils/ld/scripttempl/elf.sc.shr 2006-10-25 17:31:59.000000000 -0700
+++ binutils/ld/scripttempl/elf.sc 2007-01-04 12:24:45.000000000 -0800
@@ -236,6 +236,40 @@ STACK=" .stack ${RELOCATING-0}${
${RELOCATING+_stack = .;}
*(.stack)
}"
+test "${SHARABLE_SECTIONS}" = "yes" && OTHER_READWRITE_SECTIONS="
+ ${OTHER_READWRITE_SECTIONS}
+ /* Sharable data sections. */
+ .sharable_data ${RELOCATING-0} : ${RELOCATING+ALIGN(${MAXPAGESIZE})}
+ {
+ ${RELOCATING+PROVIDE_HIDDEN (__sharable_data_start = .);}
+ *(.sharable_data${RELOCATING+ .sharable_data.* .gnu.linkonce.shrd.*})
+ /* Align here to ensure that the sharable data section ends at the
+ page boundary. */
+ ${RELOCATING+. = ALIGN(. != 0 ? ${MAXPAGESIZE} : 1);}
+ ${RELOCATING+PROVIDE_HIDDEN (__sharable_data_end = .);}
+ }
+"
+test "${SHARABLE_SECTIONS}" = "yes" && OTHER_BSS_SECTIONS="
+ ${OTHER_BSS_SECTIONS}
+ /* Sharable bss sections */
+ .sharable_bss ${RELOCATING-0} : ${RELOCATING+ALIGN(${MAXPAGESIZE})}
+ {
+ ${RELOCATING+PROVIDE_HIDDEN (__sharable_bss_start = .);}
+ *(.dynsharablebss)
+ *(.sharable_bss${RELOCATING+ .sharable_bss.* .gnu.linkonce.shrb.*})
+ *(SHARABLE_COMMON)
+ /* Align here to ensure that the sharable bss section ends at the
+ page boundary. */
+ ${RELOCATING+. = ALIGN(. != 0 ? ${MAXPAGESIZE} : 1);}
+ ${RELOCATING+PROVIDE_HIDDEN (__sharable_bss_end = .);}
+ }
+"
+test "${SHARABLE_SECTIONS}" = "yes" && REL_SHARABLE="
+ .rel.sharable_data ${RELOCATING-0} : { *(.rel.sharable_data${RELOCATING+
.rel.sharable_data.* .rel.gnu.linkonce.shrd.*}) }
+ .rela.sharable_data ${RELOCATING-0} : { *(.rela.sharable_data${RELOCATING+
.rela.sharable_data.* .rela.gnu.linkonce.shrd.*}) }
+ .rel.sharable_bss ${RELOCATING-0} : { *(.rel.sharable_bss${RELOCATING+
.rel.sharable_bss.* .rel.gnu.linkonce.shrb.*}) }
+ .rela.sharable_bss ${RELOCATING-0} : { *(.rela.sharable_bss${RELOCATING+
.rela.sharable_bss.* .rela.gnu.linkonce.shrb.*}) }
+"
# if this is for an embedded system, don't add SIZEOF_HEADERS.
if [ -z "$EMBEDDED" ]; then
@@ -305,6 +339,7 @@ eval $COMBRELOCCAT <<EOF
.rel.got ${RELOCATING-0} : { *(.rel.got) }
.rela.got ${RELOCATING-0} : { *(.rela.got) }
${OTHER_GOT_RELOC_SECTIONS}
+ ${REL_SHARABLE}
${REL_SDATA}
${REL_SBSS}
${REL_SDATA2}
