Always define referenced __start_SECNAME/__stop_SECNAME

Currently, linker will define __start_SECNAME and __stop_SECNAME symbols
only for orphaned sections.

However, during garbage collection, ELF linker marks all sections with
references to __start_SECNAME and __stop_SECNAME symbols as used even
when section SECNAME isn't an orphaned section and linker won't define
__start_SECNAME nor __stop_SECNAME.  And ELF linker stores the first
input section whose name matches __start_SECNAME or __stop_SECNAME in
u.undef.section for garbage collection.  If these symbols are provided
in linker script, u.undef.section is set to the section where they will
defined by linker script, which leads to the incorrect output.

This patch changes linker to always define referenced __start_SECNAME and
__stop_SECNAME if the input section name is the same as the output section
name, which is always true for orphaned sections, and SECNAME is a C
identifier.  Also __start_SECNAME and __stop_SECNAME symbols are marked
as hidden by ELF linker so that __start_SECNAME and __stop_SECNAME symbols
for section SECNAME in different modules are unique.  For garbage
collection, ELF linker stores the first matched input section in the
unused vtable field.

bfd/

	PR ld/20022
	PR ld/21557
	PR ld/21562
	PR ld/21571
	* elf-bfd.h (elf_link_hash_entry): Add start_stop.  Change the
	vtable field to a union.
	(_bfd_elf_is_start_stop): Removed.
	* elf32-i386.c (elf_i386_convert_load_reloc): Also check for
	__start_SECNAME and __stop_SECNAME symbols.
	* elf64-x86-64.c (elf_x86_64_convert_load_reloc): Likewise.
	* elflink.c (_bfd_elf_is_start_stop): Removed.
	(_bfd_elf_gc_mark_rsec): Check start_stop instead of calling
	_bfd_elf_is_start_stop.
	(elf_gc_propagate_vtable_entries_used): Skip __start_SECNAME and
	__stop_SECNAME symbols.  Updated.
	(elf_gc_smash_unused_vtentry_relocs): Likewise.
	(bfd_elf_gc_record_vtinherit): Likewise.
	(bfd_elf_gc_record_vtentry): Likewise.

ld/

	PR ld/20022
	PR ld/21557
	PR ld/21562
	PR ld/21571
	* ld.texinfo: Update __start_SECNAME/__stop_SECNAME symbols.
	* ldlang.c (lang_insert_orphan): Move handling of __start_SECNAME
	and __stop_SECNAME symbols to ...
	(lang_set_startof): Here.  Also define __start_SECNAME and
	__stop_SECNAME for -Ur.
	* emultempl/elf32.em (gld${EMULATION_NAME}_after_open): Mark
	referenced __start_SECNAME and __stop_SECNAME symbols as hidden
	and set start_stop for garbage collection.
	* testsuite/ld-elf/pr21562a.d: New file.
	* testsuite/ld-elf/pr21562a.s: Likewise.
	* testsuite/ld-elf/pr21562a.t: Likewise.
	* testsuite/ld-elf/pr21562b.d: Likewise.
	* testsuite/ld-elf/pr21562b.s: Likewise.
	* testsuite/ld-elf/pr21562b.t: Likewise.
	* testsuite/ld-elf/pr21562c.d: Likewise.
	* testsuite/ld-elf/pr21562c.t: Likewise.
	* testsuite/ld-elf/pr21562d.d: Likewise.
	* testsuite/ld-elf/pr21562d.t: Likewise.
	* testsuite/ld-elf/pr21562e.d: Likewise.
	* testsuite/ld-elf/pr21562f.d: Likewise.
	* testsuite/ld-elf/pr21562g.d: Likewise.
	* testsuite/ld-elf/pr21562h.d: Likewise.
	* testsuite/ld-elf/pr21562i.d: Likewise.
	* testsuite/ld-elf/pr21562j.d: Likewise.
	* testsuite/ld-elf/pr21562k.d: Likewise.
	* testsuite/ld-elf/pr21562l.d: Likewise.
	* testsuite/ld-elf/pr21562m.d: Likewise.
	* testsuite/ld-elf/pr21562n.d: Likewise.
	* testsuite/ld-gc/pr20022.d: Likewise.
	* testsuite/ld-gc/pr20022a.s: Likewise.
	* testsuite/ld-gc/pr20022b.s: Likewise.
	* testsuite/ld-gc/gc.exp: Run PR ld/20022 tests.
	* testsuite/ld-gc/pr19161.d: Also accept local __start_SECNAME
	symbol.
	* testsuite/ld-gc/start.d: Likewise.
	* testsuite/ld-x86-64/lea1a.d: Updated.
	* testsuite/ld-x86-64/lea1b.d: Updated.
	* testsuite/ld-x86-64/lea1d.d: Updated.
	* testsuite/ld-x86-64/lea1e.d: Likewise.
This commit is contained in:
H.J. Lu 2017-06-13 08:53:22 -07:00
parent 6490dc678b
commit cbd0eecf26
39 changed files with 473 additions and 182 deletions

View File

@ -1,3 +1,24 @@
2017-06-13 H.J. Lu <hongjiu.lu@intel.com>
PR ld/20022
PR ld/21557
PR ld/21562
PR ld/21571
* elf-bfd.h (elf_link_hash_entry): Add start_stop. Change the
vtable field to a union.
(_bfd_elf_is_start_stop): Removed.
* elf32-i386.c (elf_i386_convert_load_reloc): Also check for
__start_SECNAME and __stop_SECNAME symbols.
* elf64-x86-64.c (elf_x86_64_convert_load_reloc): Likewise.
* elflink.c (_bfd_elf_is_start_stop): Removed.
(_bfd_elf_gc_mark_rsec): Check start_stop instead of calling
_bfd_elf_is_start_stop.
(elf_gc_propagate_vtable_entries_used): Skip __start_SECNAME and
__stop_SECNAME symbols. Updated.
(elf_gc_smash_unused_vtentry_relocs): Likewise.
(bfd_elf_gc_record_vtinherit): Likewise.
(bfd_elf_gc_record_vtentry): Likewise.
2017-06-13 Nick Clifton <nickc@redhat.com>
PR ld/21524

View File

@ -213,6 +213,9 @@ struct elf_link_hash_entry
/* Symbol is defined by a shared library with non-default visibility
in a read/write section. */
unsigned int protected_def : 1;
/* Symbol is __start_SECNAME or __stop_SECNAME to mark section
SECNAME. */
unsigned int start_stop : 1;
/* String table index in .dynstr if this is a dynamic symbol. */
unsigned long dynstr_index;
@ -243,7 +246,15 @@ struct elf_link_hash_entry
struct bfd_elf_version_tree *vertree;
} verinfo;
struct elf_link_virtual_table_entry *vtable;
union
{
/* For __start_SECNAME and __stop_SECNAME symbols, record the first
input section whose section name is SECNAME. */
asection *start_stop_section;
/* Vtable information. */
struct elf_link_virtual_table_entry *vtable;
} u2;
};
/* Will references to this symbol always reference the symbol
@ -2445,9 +2456,6 @@ extern bfd_boolean bfd_elf_gc_common_finalize_got_offsets
extern bfd_boolean bfd_elf_gc_common_final_link
(bfd *, struct bfd_link_info *);
extern asection *_bfd_elf_is_start_stop
(const struct bfd_link_info *, struct elf_link_hash_entry *);
extern bfd_boolean bfd_elf_reloc_symbol_deleted_p
(bfd_vma, void *);

View File

@ -1787,11 +1787,13 @@ convert_branch:
return TRUE;
/* def_regular is set by an assignment in a linker script in
bfd_elf_record_link_assignment. */
if ((h->def_regular
|| h->root.type == bfd_link_hash_defined
|| h->root.type == bfd_link_hash_defweak)
&& SYMBOL_REFERENCES_LOCAL (link_info, h))
bfd_elf_record_link_assignment. start_stop is set on
__start_SECNAME/__stop_SECNAME which mark section SECNAME. */
if (h->start_stop
|| ((h->def_regular
|| h->root.type == bfd_link_hash_defined
|| h->root.type == bfd_link_hash_defweak)
&& SYMBOL_REFERENCES_LOCAL (link_info, h)))
{
convert_load:
if (opcode == 0x8b)

View File

@ -1920,21 +1920,25 @@ elf_x86_64_convert_load_reloc (bfd *abfd, asection *sec,
}
/* Avoid optimizing GOTPCREL relocations againt _DYNAMIC since
ld.so may use its link-time address. */
else if ((h->def_regular
|| h->root.type == bfd_link_hash_defined
|| h->root.type == bfd_link_hash_defweak)
&& h != htab->elf.hdynamic
&& SYMBOL_REFERENCES_LOCAL (link_info, h))
else if (h->start_stop
|| ((h->def_regular
|| h->root.type == bfd_link_hash_defined
|| h->root.type == bfd_link_hash_defweak)
&& h != htab->elf.hdynamic
&& SYMBOL_REFERENCES_LOCAL (link_info, h)))
{
/* bfd_link_hash_new or bfd_link_hash_undefined is
set by an assignment in a linker script in
bfd_elf_record_link_assignment. */
if (h->def_regular
&& (h->root.type == bfd_link_hash_new
|| h->root.type == bfd_link_hash_undefined
|| ((h->root.type == bfd_link_hash_defined
|| h->root.type == bfd_link_hash_defweak)
&& h->root.u.def.section == bfd_und_section_ptr)))
bfd_elf_record_link_assignment. start_stop is set
on __start_SECNAME/__stop_SECNAME which mark section
SECNAME. */
if (h->start_stop
|| (h->def_regular
&& (h->root.type == bfd_link_hash_new
|| h->root.type == bfd_link_hash_undefined
|| ((h->root.type == bfd_link_hash_defined
|| h->root.type == bfd_link_hash_defweak)
&& h->root.u.def.section == bfd_und_section_ptr))))
{
/* Skip since R_X86_64_32/R_X86_64_32S may overflow. */
if (require_reloc_pc32)

View File

@ -12698,55 +12698,6 @@ elf_gc_mark_debug_section (asection *sec ATTRIBUTE_UNUSED,
return NULL;
}
/* For undefined __start_<name> and __stop_<name> symbols, return the
first input section matching <name>. Return NULL otherwise. */
asection *
_bfd_elf_is_start_stop (const struct bfd_link_info *info,
struct elf_link_hash_entry *h)
{
asection *s;
const char *sec_name;
if (h->root.type != bfd_link_hash_undefined
&& h->root.type != bfd_link_hash_undefweak)
return NULL;
s = h->root.u.undef.section;
if (s != NULL)
{
if (s == (asection *) 0 - 1)
return NULL;
return s;
}
sec_name = NULL;
if (strncmp (h->root.root.string, "__start_", 8) == 0)
sec_name = h->root.root.string + 8;
else if (strncmp (h->root.root.string, "__stop_", 7) == 0)
sec_name = h->root.root.string + 7;
if (sec_name != NULL && *sec_name != '\0')
{
bfd *i;
for (i = info->input_bfds; i != NULL; i = i->link.next)
{
s = bfd_get_section_by_name (i, sec_name);
if (s != NULL)
{
h->root.u.undef.section = s;
break;
}
}
}
if (s == NULL)
h->root.u.undef.section = (asection *) 0 - 1;
return s;
}
/* COOKIE->rel describes a relocation against section SEC, which is
a section we've decided to keep. Return the section that contains
the relocation symbol, or NULL if no section contains it. */
@ -12792,10 +12743,9 @@ _bfd_elf_gc_mark_rsec (struct bfd_link_info *info, asection *sec,
or __stop_XXX symbols. The linker will later define such
symbols for orphan input sections that have a name
representable as a C identifier. */
asection *s = _bfd_elf_is_start_stop (info, h);
if (s != NULL)
if (h->start_stop)
{
asection *s = h->u2.start_stop_section;
*start_stop = !s->gc_mark;
return s;
}
@ -13136,26 +13086,28 @@ static bfd_boolean
elf_gc_propagate_vtable_entries_used (struct elf_link_hash_entry *h, void *okp)
{
/* Those that are not vtables. */
if (h->vtable == NULL || h->vtable->parent == NULL)
if (h->start_stop
|| h->u2.vtable == NULL
|| h->u2.vtable->parent == NULL)
return TRUE;
/* Those vtables that do not have parents, we cannot merge. */
if (h->vtable->parent == (struct elf_link_hash_entry *) -1)
if (h->u2.vtable->parent == (struct elf_link_hash_entry *) -1)
return TRUE;
/* If we've already been done, exit. */
if (h->vtable->used && h->vtable->used[-1])
if (h->u2.vtable->used && h->u2.vtable->used[-1])
return TRUE;
/* Make sure the parent's table is up to date. */
elf_gc_propagate_vtable_entries_used (h->vtable->parent, okp);
elf_gc_propagate_vtable_entries_used (h->u2.vtable->parent, okp);
if (h->vtable->used == NULL)
if (h->u2.vtable->used == NULL)
{
/* None of this table's entries were referenced. Re-use the
parent's table. */
h->vtable->used = h->vtable->parent->vtable->used;
h->vtable->size = h->vtable->parent->vtable->size;
h->u2.vtable->used = h->u2.vtable->parent->u2.vtable->used;
h->u2.vtable->size = h->u2.vtable->parent->u2.vtable->size;
}
else
{
@ -13163,9 +13115,9 @@ elf_gc_propagate_vtable_entries_used (struct elf_link_hash_entry *h, void *okp)
bfd_boolean *cu, *pu;
/* Or the parent's entries into ours. */
cu = h->vtable->used;
cu = h->u2.vtable->used;
cu[-1] = TRUE;
pu = h->vtable->parent->vtable->used;
pu = h->u2.vtable->parent->u2.vtable->used;
if (pu != NULL)
{
const struct elf_backend_data *bed;
@ -13173,7 +13125,7 @@ elf_gc_propagate_vtable_entries_used (struct elf_link_hash_entry *h, void *okp)
bed = get_elf_backend_data (h->root.u.def.section->owner);
log_file_align = bed->s->log_file_align;
n = h->vtable->parent->vtable->size >> log_file_align;
n = h->u2.vtable->parent->u2.vtable->size >> log_file_align;
while (n--)
{
if (*pu)
@ -13198,7 +13150,9 @@ elf_gc_smash_unused_vtentry_relocs (struct elf_link_hash_entry *h, void *okp)
/* Take care of both those symbols that do not describe vtables as
well as those that are not loaded. */
if (h->vtable == NULL || h->vtable->parent == NULL)
if (h->start_stop
|| h->u2.vtable == NULL
|| h->u2.vtable->parent == NULL)
return TRUE;
BFD_ASSERT (h->root.type == bfd_link_hash_defined
@ -13220,11 +13174,11 @@ elf_gc_smash_unused_vtentry_relocs (struct elf_link_hash_entry *h, void *okp)
if (rel->r_offset >= hstart && rel->r_offset < hend)
{
/* If the entry is in use, do nothing. */
if (h->vtable->used
&& (rel->r_offset - hstart) < h->vtable->size)
if (h->u2.vtable->used
&& (rel->r_offset - hstart) < h->u2.vtable->size)
{
bfd_vma entry = (rel->r_offset - hstart) >> log_file_align;
if (h->vtable->used[entry])
if (h->u2.vtable->used[entry])
continue;
}
/* Otherwise, kill it. */
@ -13448,11 +13402,11 @@ bfd_elf_gc_record_vtinherit (bfd *abfd,
return FALSE;
win:
if (!child->vtable)
if (!child->u2.vtable)
{
child->vtable = ((struct elf_link_virtual_table_entry *)
bfd_zalloc (abfd, sizeof (*child->vtable)));
if (!child->vtable)
child->u2.vtable = ((struct elf_link_virtual_table_entry *)
bfd_zalloc (abfd, sizeof (*child->u2.vtable)));
if (!child->u2.vtable)
return FALSE;
}
if (!h)
@ -13462,10 +13416,10 @@ bfd_elf_gc_record_vtinherit (bfd *abfd,
would be bad. It isn't worth paging in the local symbols to be
sure though; that case should simply be handled by the assembler. */
child->vtable->parent = (struct elf_link_hash_entry *) -1;
child->u2.vtable->parent = (struct elf_link_hash_entry *) -1;
}
else
child->vtable->parent = h;
child->u2.vtable->parent = h;
return TRUE;
}
@ -13481,18 +13435,18 @@ bfd_elf_gc_record_vtentry (bfd *abfd ATTRIBUTE_UNUSED,
const struct elf_backend_data *bed = get_elf_backend_data (abfd);
unsigned int log_file_align = bed->s->log_file_align;
if (!h->vtable)
if (!h->u2.vtable)
{
h->vtable = ((struct elf_link_virtual_table_entry *)
bfd_zalloc (abfd, sizeof (*h->vtable)));
if (!h->vtable)
h->u2.vtable = ((struct elf_link_virtual_table_entry *)
bfd_zalloc (abfd, sizeof (*h->u2.vtable)));
if (!h->u2.vtable)
return FALSE;
}
if (addend >= h->vtable->size)
if (addend >= h->u2.vtable->size)
{
size_t size, bytes, file_align;
bfd_boolean *ptr = h->vtable->used;
bfd_boolean *ptr = h->u2.vtable->used;
/* While the symbol is undefined, we have to be prepared to handle
a zero size. */
@ -13523,7 +13477,7 @@ bfd_elf_gc_record_vtentry (bfd *abfd ATTRIBUTE_UNUSED,
{
size_t oldbytes;
oldbytes = (((h->vtable->size >> log_file_align) + 1)
oldbytes = (((h->u2.vtable->size >> log_file_align) + 1)
* sizeof (bfd_boolean));
memset (((char *) ptr) + oldbytes, 0, bytes - oldbytes);
}
@ -13535,11 +13489,11 @@ bfd_elf_gc_record_vtentry (bfd *abfd ATTRIBUTE_UNUSED,
return FALSE;
/* And arrange for that done flag to be at index -1. */
h->vtable->used = ptr + 1;
h->vtable->size = size;
h->u2.vtable->used = ptr + 1;
h->u2.vtable->size = size;
}
h->vtable->used[addend >> log_file_align] = TRUE;
h->u2.vtable->used[addend >> log_file_align] = TRUE;
return TRUE;
}

View File

@ -1,3 +1,49 @@
2017-06-13 H.J. Lu <hongjiu.lu@intel.com>
PR ld/20022
PR ld/21557
PR ld/21562
PR ld/21571
* ld.texinfo: Update __start_SECNAME/__stop_SECNAME symbols.
* ldlang.c (lang_insert_orphan): Move handling of __start_SECNAME
and __stop_SECNAME symbols to ...
(lang_set_startof): Here. Also define __start_SECNAME and
__stop_SECNAME for -Ur.
* emultempl/elf32.em (gld${EMULATION_NAME}_after_open): Mark
referenced __start_SECNAME and __stop_SECNAME symbols as hidden
and set start_stop for garbage collection.
* testsuite/ld-elf/pr21562a.d: New file.
* testsuite/ld-elf/pr21562a.s: Likewise.
* testsuite/ld-elf/pr21562a.t: Likewise.
* testsuite/ld-elf/pr21562b.d: Likewise.
* testsuite/ld-elf/pr21562b.s: Likewise.
* testsuite/ld-elf/pr21562b.t: Likewise.
* testsuite/ld-elf/pr21562c.d: Likewise.
* testsuite/ld-elf/pr21562c.t: Likewise.
* testsuite/ld-elf/pr21562d.d: Likewise.
* testsuite/ld-elf/pr21562d.t: Likewise.
* testsuite/ld-elf/pr21562e.d: Likewise.
* testsuite/ld-elf/pr21562f.d: Likewise.
* testsuite/ld-elf/pr21562g.d: Likewise.
* testsuite/ld-elf/pr21562h.d: Likewise.
* testsuite/ld-elf/pr21562i.d: Likewise.
* testsuite/ld-elf/pr21562j.d: Likewise.
* testsuite/ld-elf/pr21562k.d: Likewise.
* testsuite/ld-elf/pr21562l.d: Likewise.
* testsuite/ld-elf/pr21562m.d: Likewise.
* testsuite/ld-elf/pr21562n.d: Likewise.
* testsuite/ld-gc/pr20022.d: Likewise.
* testsuite/ld-gc/pr20022a.s: Likewise.
* testsuite/ld-gc/pr20022b.s: Likewise.
* testsuite/ld-gc/gc.exp: Run PR ld/20022 tests.
* testsuite/ld-gc/pr19161.d: Also accept local __start_SECNAME
symbol.
* testsuite/ld-gc/start.d: Likewise.
* testsuite/ld-x86-64/lea1a.d: Updated.
* testsuite/ld-x86-64/lea1b.d: Updated.
* testsuite/ld-x86-64/lea1d.d: Updated.
* testsuite/ld-x86-64/lea1e.d: Likewise.
2017-06-13 H.J. Lu <hongjiu.lu@intel.com>
* testsuite/ld-elf/sizeof.d: New file.

View File

@ -1216,6 +1216,9 @@ gld${EMULATION_NAME}_after_open (void)
{
struct bfd_link_needed_list *needed, *l;
struct elf_link_hash_table *htab;
asection *s;
bfd *abfd;
char leading_char;
after_open_default ();
@ -1239,8 +1242,6 @@ gld${EMULATION_NAME}_after_open (void)
if (emit_note_gnu_build_id != NULL)
{
bfd *abfd;
/* Find an ELF input. */
for (abfd = link_info.input_bfds;
abfd != (bfd *) NULL; abfd = abfd->link.next)
@ -1276,11 +1277,66 @@ gld${EMULATION_NAME}_after_open (void)
return;
}
leading_char = bfd_get_symbol_leading_char (link_info.output_bfd);
/* Check for input sections whose names match references to
__start_SECNAME or __stop_SECNAME symbols. Mark the matched
symbols as hidden and set start_stop for garbage collection. */
for (abfd = link_info.input_bfds; abfd; abfd = abfd->link.next)
for (s = abfd->sections; s; s = s->next)
{
const char *name = bfd_get_section_name (abfd, s);
const char *ps;
for (ps = name; *ps != '\0'; ps++)
if (!ISALNUM ((unsigned char) *ps) && *ps != '_')
break;
if (*ps == '\0')
{
struct elf_link_hash_entry *h;
char *symbol = (char *) xmalloc (ps - name
+ sizeof "__start_" + 1);
symbol[0] = leading_char;
sprintf (symbol + (leading_char != 0), "__start_%s", name);
h = elf_link_hash_lookup (elf_hash_table (&link_info),
symbol, FALSE, FALSE, TRUE);
if (h != NULL
&& (h->root.type == bfd_link_hash_undefined
|| h->root.type == bfd_link_hash_undefweak)
&& h->u2.start_stop_section == NULL)
{
h->start_stop = 1;
h->u2.start_stop_section = s;
_bfd_elf_link_hash_hide_symbol (&link_info, h, TRUE);
if (ELF_ST_VISIBILITY (h->other) != STV_INTERNAL)
h->other = ((h->other & ~ELF_ST_VISIBILITY (-1))
| STV_HIDDEN);
}
symbol[0] = leading_char;
sprintf (symbol + (leading_char != 0), "__stop_%s", name);
h = elf_link_hash_lookup (elf_hash_table (&link_info),
symbol, FALSE, FALSE, TRUE);
if (h != NULL
&& (h->root.type == bfd_link_hash_undefined
|| h->root.type == bfd_link_hash_undefweak)
&& h->u2.start_stop_section == NULL)
{
h->start_stop = 1;
h->u2.start_stop_section = s;
_bfd_elf_link_hash_hide_symbol (&link_info, h, TRUE);
if (ELF_ST_VISIBILITY (h->other) != STV_INTERNAL)
h->other = ((h->other & ~ELF_ST_VISIBILITY (-1))
| STV_HIDDEN);
}
}
}
if (!link_info.traditional_format)
{
bfd *abfd, *elfbfd = NULL;
bfd *elfbfd = NULL;
bfd_boolean warn_eh_frame = FALSE;
asection *s;
int seen_type = 0;
for (abfd = link_info.input_bfds; abfd; abfd = abfd->link.next)

View File

@ -4657,6 +4657,14 @@ SECTIONS @{
@end group
@end smallexample
If an output section's name is the same as the input section's name
and is representable as a C identifier, then the linker will
automatically @pxref{PROVIDE} two symbols: __start_SECNAME and
__stop_SECNAME, where SECNAME is the name of the section. These
indicate the start address and end address of the output section
respectively. Note: most section names are not representable as
C identifiers because they contain a @samp{.} character.
@node Output Section Data
@subsection Output Section Data
@cindex data
@ -5841,14 +5849,6 @@ The command line options @samp{--orphan-handling} and @samp{--unique}
(@pxref{Options,,Command Line Options}) can be used to control which
output sections an orphan is placed in.
If an orphaned section's name is representable as a C identifier then
the linker will automatically @pxref{PROVIDE} two symbols:
__start_SECNAME and __stop_SECNAME, where SECNAME is the name of the
section. These indicate the start address and end address of the
orphaned section respectively. Note: most section names are not
representable as C identifiers because they contain a @samp{.}
character.
@node Location Counter
@subsection The Location Counter
@kindex .

View File

@ -1829,8 +1829,6 @@ lang_insert_orphan (asection *s,
lang_statement_list_type *add_child)
{
lang_statement_list_type add;
const char *ps;
lang_assignment_statement_type *start_assign;
lang_output_section_statement_type *os;
lang_output_section_statement_type **os_tail;
@ -1852,29 +1850,6 @@ lang_insert_orphan (asection *s,
os = lang_enter_output_section_statement (secname, address, normal_section,
NULL, NULL, NULL, constraint, 0);
ps = NULL;
start_assign = NULL;
if (config.build_constructors && *os_tail == os)
{
/* If the name of the section is representable in C, then create
symbols to mark the start and the end of the section. */
for (ps = secname; *ps != '\0'; ps++)
if (!ISALNUM ((unsigned char) *ps) && *ps != '_')
break;
if (*ps == '\0')
{
char *symname;
symname = (char *) xmalloc (ps - secname + sizeof "__start_" + 1);
symname[0] = bfd_get_symbol_leading_char (link_info.output_bfd);
sprintf (symname + (symname[0] != 0), "__start_%s", secname);
start_assign
= lang_add_assignment (exp_provide (symname,
exp_nameop (NAME, "."),
FALSE));
}
}
if (add_child == NULL)
add_child = &os->children;
lang_add_section (add_child, s, NULL, os);
@ -1894,27 +1869,6 @@ lang_insert_orphan (asection *s,
lang_leave_output_section_statement (NULL, DEFAULT_MEMORY_REGION, NULL,
NULL);
if (start_assign != NULL)
{
char *symname;
lang_assignment_statement_type *stop_assign;
bfd_vma dot;
symname = (char *) xmalloc (ps - secname + sizeof "__stop_" + 1);
symname[0] = bfd_get_symbol_leading_char (link_info.output_bfd);
sprintf (symname + (symname[0] != 0), "__stop_%s", secname);
stop_assign
= lang_add_assignment (exp_provide (symname,
exp_nameop (NAME, "."),
FALSE));
/* Evaluate the expression to define the symbol if referenced,
before sizing dynamic sections. */
dot = os->bfd_section->vma;
exp_fold_tree (start_assign->exp, os->bfd_section, &dot);
dot += TO_ADDR (s->size);
exp_fold_tree (stop_assign->exp, os->bfd_section, &dot);
}
/* Restore the global list pointer. */
if (after != NULL)
pop_stat_ptr ();
@ -5924,20 +5878,25 @@ section_for_dot (void)
return bfd_abs_section_ptr;
}
/* Fix any .startof. or .sizeof. symbols. When the assemblers see the
operator .startof. (section_name), it produces an undefined symbol
.startof.section_name. Similarly, when it sees
/* Fix any .startof., .sizeof., __start or __stop symbols. When the
assemblers see the operator .startof. (section_name), it produces
an undefined symbol .startof.section_name. Similarly, when it sees
.sizeof. (section_name), it produces an undefined symbol
.sizeof.section_name. For all the output sections, we look for
such symbols, and set them to the correct value. */
.sizeof.section_name. Also for ELF linker, __start_XXX or __stop_XXX
symbols should be resolved to the start and end of section XXX. For
all the output sections, we look for such symbols, and set them to
the correct value. */
static void
lang_set_startof (void)
{
asection *s;
char leading_char;
bfd_boolean is_elf = (bfd_get_flavour (link_info.output_bfd)
== bfd_target_elf_flavour);
bfd_boolean is_elocatable = bfd_link_relocatable (&link_info);
if (bfd_link_relocatable (&link_info))
return;
leading_char = bfd_get_symbol_leading_char (link_info.output_bfd);
for (s = link_info.output_bfd->sections; s != NULL; s = s->next)
{
@ -5948,24 +5907,58 @@ lang_set_startof (void)
secname = bfd_get_section_name (link_info.output_bfd, s);
buf = (char *) xmalloc (10 + strlen (secname));
sprintf (buf, ".startof.%s", secname);
h = bfd_link_hash_lookup (link_info.hash, buf, FALSE, FALSE, TRUE);
if (h != NULL && h->type == bfd_link_hash_undefined)
if (!is_elocatable)
{
sprintf (buf, ".startof.%s", secname);
h = bfd_link_hash_lookup (link_info.hash, buf, FALSE, FALSE,
TRUE);
if (h != NULL && h->type == bfd_link_hash_undefined)
{
h->type = bfd_link_hash_defined;
h->u.def.value = 0;
h->u.def.section = s;
}
sprintf (buf, ".sizeof.%s", secname);
h = bfd_link_hash_lookup (link_info.hash, buf, FALSE, FALSE,
TRUE);
if (h != NULL && h->type == bfd_link_hash_undefined)
{
h->type = bfd_link_hash_defined;
h->u.def.value = TO_ADDR (s->size);
h->u.def.section = bfd_abs_section_ptr;
}
}
buf[0] = leading_char;
sprintf (buf + (buf[0] != 0), "__start_%s", secname);
h = bfd_link_hash_lookup (link_info.hash, buf, FALSE, FALSE,
TRUE);
if (h != NULL
&& (h->type == bfd_link_hash_undefined
|| h->type == bfd_link_hash_undefweak))
{
h->type = bfd_link_hash_defined;
h->u.def.value = 0;
h->u.def.section = s;
if (is_elf)
((struct elf_link_hash_entry *) h)->def_regular = 1;
}
sprintf (buf, ".sizeof.%s", secname);
h = bfd_link_hash_lookup (link_info.hash, buf, FALSE, FALSE, TRUE);
if (h != NULL && h->type == bfd_link_hash_undefined)
buf[0] = leading_char;
sprintf (buf + (buf[0] != 0), "__stop_%s", secname);
h = bfd_link_hash_lookup (link_info.hash, buf, FALSE, FALSE,
TRUE);
if (h != NULL
&& (h->type == bfd_link_hash_undefined
|| h->type == bfd_link_hash_undefweak))
{
h->type = bfd_link_hash_defined;
h->u.def.value = TO_ADDR (s->size);
h->u.def.section = bfd_abs_section_ptr;
h->u.def.section = s;
if (is_elf)
((struct elf_link_hash_entry *) h)->def_regular = 1;
}
free (buf);
}
}

View File

@ -0,0 +1,9 @@
#ld: -shared -z defs --gc-sections
#readelf: -s -S --wide
#target: *-*-linux* *-*-gnu*
#...
\[[ 0-9]+\] scnfoo[ \t]+PROGBITS[ \t]+[0-9a-f]+ +[0-9a-f]+ +0*10[ \t]+.*
#...
+[0-9]+: +[0-9a-f]+ +[0-9a-f]+ +NOTYPE +LOCAL +DEFAULT +[0-9]+ +__start_scnfoo
#pass

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@ -0,0 +1,8 @@
.section scnfoo,"aw",%progbits
.zero 0x10
.globl bar
.data
.type bar, %object
bar:
.dc.a __start_scnfoo

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@ -0,0 +1,3 @@
SECTIONS {
scnfoo : { *(scnfoo) }
}

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@ -0,0 +1,9 @@
#ld: -shared -z defs --gc-sections
#readelf: -s -S --wide
#target: *-*-linux* *-*-gnu*
#...
\[[ 0-9]+\] scnfoo[ \t]+PROGBITS[ \t]+[0-9a-f]+ +[0-9a-f]+ +0*10[ \t]+.*
#...
+[0-9]+: +[0-9a-f]+ +[0-9a-f]+ +NOTYPE +LOCAL +DEFAULT +[0-9]+ +__stop_scnfoo
#pass

View File

@ -0,0 +1,8 @@
.section scnfoo,"aw",%progbits
.zero 0x10
.globl bar
.data
.type bar, %object
bar:
.dc.a __stop_scnfoo

View File

@ -0,0 +1,5 @@
SECTIONS {
PROVIDE (__start_scnfoo = .);
scnfoo : { *(scnfoo) }
PROVIDE (__stop_scnfoo = .);
}

View File

@ -0,0 +1,10 @@
#source: pr21562a.s
#ld: -shared -z defs --gc-sections -T pr21562a.t
#readelf: -s -S --wide
#target: *-*-linux* *-*-gnu*
#...
\[[ 0-9]+\] scnfoo[ \t]+PROGBITS[ \t]+[0-9a-f]+ +[0-9a-f]+ +0*10[ \t]+.*
#...
+[0-9]+: +[0-9a-f]+ +[0-9a-f]+ +NOTYPE +LOCAL +DEFAULT +[0-9]+ +__start_scnfoo
#pass

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@ -0,0 +1,7 @@
SECTIONS {
.foo : {
PROVIDE (__start_scnfoo = .);
*(scnfoo)
PROVIDE (__stop_scnfoo = .);
}
}

View File

@ -0,0 +1,10 @@
#source: pr21562b.s
#ld: -shared -z defs --gc-sections -T pr21562a.t
#readelf: -s -S --wide
#target: *-*-linux* *-*-gnu*
#...
\[[ 0-9]+\] scnfoo[ \t]+PROGBITS[ \t]+[0-9a-f]+ +[0-9a-f]+ +0*10[ \t]+.*
#...
+[0-9]+: +[0-9a-f]+ +[0-9a-f]+ +NOTYPE +LOCAL +DEFAULT +[0-9]+ +__stop_scnfoo
#pass

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@ -0,0 +1,5 @@
SECTIONS {
PROVIDE (__start_scnfoo = .);
.foo : { *(scnfoo) }
PROVIDE (__stop_scnfoo = .);
}

View File

@ -0,0 +1,10 @@
#source: pr21562a.s
#ld: -shared -z defs
#readelf: -s -S --wide
#target: *-*-linux* *-*-gnu*
#...
\[[ 0-9]+\] scnfoo[ \t]+PROGBITS[ \t]+[0-9a-f]+ +[0-9a-f]+ +0*10[ \t]+.*
#...
+[0-9]+: +[0-9a-f]+ +[0-9a-f]+ +NOTYPE +LOCAL +DEFAULT +[0-9]+ +__start_scnfoo
#pass

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@ -0,0 +1,10 @@
#source: pr21562b.s
#ld: -shared -z defs
#readelf: -s -S --wide
#target: *-*-linux* *-*-gnu*
#...
\[[ 0-9]+\] scnfoo[ \t]+PROGBITS[ \t]+[0-9a-f]+ +[0-9a-f]+ +0*10[ \t]+.*
#...
+[0-9]+: +[0-9a-f]+ +[0-9a-f]+ +NOTYPE +LOCAL +DEFAULT +[0-9]+ +__stop_scnfoo
#pass

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@ -0,0 +1,10 @@
#source: pr21562a.s
#ld: -shared -z defs -T pr21562a.t
#readelf: -s -S --wide
#target: *-*-linux* *-*-gnu*
#...
\[[ 0-9]+\] scnfoo[ \t]+PROGBITS[ \t]+[0-9a-f]+ +[0-9a-f]+ +0*10[ \t]+.*
#...
+[0-9]+: +[0-9a-f]+ +[0-9a-f]+ +NOTYPE +LOCAL +DEFAULT +[0-9]+ +__start_scnfoo
#pass

View File

@ -0,0 +1,10 @@
#source: pr21562b.s
#ld: -shared -z defs -T pr21562a.t
#readelf: -s -S --wide
#target: *-*-linux* *-*-gnu*
#...
\[[ 0-9]+\] scnfoo[ \t]+PROGBITS[ \t]+[0-9a-f]+ +[0-9a-f]+ +0*10[ \t]+.*
#...
+[0-9]+: +[0-9a-f]+ +[0-9a-f]+ +NOTYPE +LOCAL +DEFAULT +[0-9]+ +__stop_scnfoo
#pass

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@ -0,0 +1,10 @@
#source: pr21562a.s
#ld: -shared -z defs --gc-sections -T pr21562b.t
#readelf: -s -S --wide
#target: *-*-linux* *-*-gnu*
#...
\[[ 0-9]+\] scnfoo[ \t]+PROGBITS[ \t]+[0-9a-f]+ +[0-9a-f]+ +0*10[ \t]+.*
#...
+[0-9]+: +[0-9a-f]+ +[0-9a-f]+ +NOTYPE +LOCAL +DEFAULT +[0-9]+ +__start_scnfoo
#pass

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@ -0,0 +1,10 @@
#source: pr21562b.s
#ld: -shared -z defs --gc-sections -T pr21562b.t
#readelf: -s -S --wide
#target: *-*-linux* *-*-gnu*
#...
\[[ 0-9]+\] scnfoo[ \t]+PROGBITS[ \t]+[0-9a-f]+ +[0-9a-f]+ +0*10[ \t]+.*
#...
+[0-9]+: +[0-9a-f]+ +[0-9a-f]+ +NOTYPE +LOCAL +DEFAULT +[0-9]+ +__stop_scnfoo
#pass

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@ -0,0 +1,10 @@
#source: pr21562a.s
#ld: -shared -z defs --gc-sections -T pr21562c.t
#readelf: -s -S --wide
#target: *-*-linux* *-*-gnu*
#...
\[[ 0-9]+\] \.foo[ \t]+PROGBITS[ \t]+[0-9a-f]+ +[0-9a-f]+ +0*10[ \t]+.*
#...
+[0-9]+: +[0-9a-f]+ +[0-9a-f]+ +NOTYPE +LOCAL +DEFAULT +[0-9]+ +__start_scnfoo
#pass

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@ -0,0 +1,10 @@
#source: pr21562b.s
#ld: -shared -z defs --gc-sections -T pr21562c.t
#readelf: -s -S --wide
#target: *-*-linux* *-*-gnu*
#...
\[[ 0-9]+\] \.foo[ \t]+PROGBITS[ \t]+[0-9a-f]+ +[0-9a-f]+ +0*10[ \t]+.*
#...
+[0-9]+: +[0-9a-f]+ +[0-9a-f]+ +NOTYPE +LOCAL +DEFAULT +[0-9]+ +__stop_scnfoo
#pass

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@ -0,0 +1,10 @@
#source: pr21562a.s
#ld: -shared -z defs --gc-sections -T pr21562d.t
#readelf: -s -S --wide
#target: *-*-linux* *-*-gnu*
#...
\[[ 0-9]+\] \.foo[ \t]+PROGBITS[ \t]+[0-9a-f]+ +[0-9a-f]+ +0*10[ \t]+.*
#...
+[0-9]+: +[0-9a-f]+ +[0-9a-f]+ +NOTYPE +LOCAL +DEFAULT +[0-9]+ +__start_scnfoo
#pass

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@ -0,0 +1,10 @@
#source: pr21562b.s
#ld: -shared -z defs --gc-sections -T pr21562d.t
#readelf: -s -S --wide
#target: *-*-linux* *-*-gnu*
#...
\[[ 0-9]+\] \.foo[ \t]+PROGBITS[ \t]+[0-9a-f]+ +[0-9a-f]+ +0*10[ \t]+.*
#...
+[0-9]+: +[0-9a-f]+ +[0-9a-f]+ +NOTYPE +LOCAL +DEFAULT +[0-9]+ +__stop_scnfoo
#pass

View File

@ -119,6 +119,12 @@ if { [is_elf_format] && [check_shared_lib_support] } then {
run_dump_test "personality"
}
run_dump_test "pr18223"
if {![ld_assemble_flags $as $gasopt $srcdir/$subdir/pr20022a.s tmpdir/pr20022a.o]
|| ![ld_link $ld tmpdir/pr20022.so "-shared --gc-sections tmpdir/pr20022a.o"] } then {
fail pr20022
} else {
run_dump_test "pr20022"
}
}
if { [is_remote host] || [which $CC] != 0 } {

View File

@ -6,5 +6,5 @@
#xfail: mips64vr-*-* msp430-*-* powerpc*-*-eabivle rl78-*-* rx-*-* sh*-*-*
#...
0*[1-9a-f]+[0-9a-f]*[ ](D)[ ]_*__start_my_section
0*[1-9a-f]+[0-9a-f]*[ ](d|D)[ ]_*__start_my_section
#...

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@ -0,0 +1,11 @@
#source: pr20022b.s
#ld: --gc-sections -e _start tmpdir/pr20022.so
#readelf: -SsW
#target: *-*-linux* *-*-gnu*
#notarget: *-*-*aout *-*-*oldld frv-*-linux* metag-*-linux*
#...
\[[ 0-9]+\] _foo[ \t]+PROGBITS[ \t]+[0-9a-f]+ +[0-9a-f]+ +[0-9a-f]+[ \t]+.*
#...
+[0-9]+: +[0-9a-f]+ +[0-9a-f]+ +NOTYPE +LOCAL +DEFAULT +[0-9]+ +__start__foo
#pass

View File

@ -0,0 +1,8 @@
.data
.globl bar
.type bar,%object
bar:
.dc.a __start__foo
.section _foo,"aw",%progbits
foo:
.ascii "This is bar"

View File

@ -0,0 +1,8 @@
.text
.globl _start
_start:
.dc.a __start__foo
.dc.a bar
.section _foo,"aw",%progbits
foo:
.ascii "This is foo"

View File

@ -5,5 +5,5 @@
#notarget: *-*-*aout *-*-*oldld frv-*-linux* metag-*-linux*
#...
[0-9a-f]+ D +__start__foo
[0-9a-f]+ d +__start__foo
#...

View File

@ -15,5 +15,5 @@ Disassembly of section .text:
[ ]*[a-f0-9]+: 48 8d 05 ([0-9a-f]{2} ){4} * lea -0x[a-f0-9]+\(%rip\),%rax # [a-f0-9]+ <foo>
[ ]*[a-f0-9]+: 4c 8d 1d ([0-9a-f]{2} ){4} * lea 0x[a-f0-9]+\(%rip\),%r11 # [a-f0-9]+ <bar>
[ ]*[a-f0-9]+: 48 8d 05 ([0-9a-f]{2} ){4} * lea 0x[a-f0-9]+\(%rip\),%rax # [a-f0-9]+ <__start_my_section>
[ ]*[a-f0-9]+: 4c 8d 1d ([0-9a-f]{2} ){4} * lea 0x[a-f0-9]+\(%rip\),%r11 # [a-f0-9]+ <__stop_my_section>
[ ]*[a-f0-9]+: 4c 8d 1d ([0-9a-f]{2} ){4} * lea 0x[a-f0-9]+\(%rip\),%r11 # [a-f0-9]+ <.*>
#pass

View File

@ -15,5 +15,5 @@ Disassembly of section .text:
[ ]*[a-f0-9]+: 48 8d 05 ([0-9a-f]{2} ){4} * lea -0x[a-f0-9]+\(%rip\),%rax # [a-f0-9]+ <foo>
[ ]*[a-f0-9]+: 4c 8d 1d ([0-9a-f]{2} ){4} * lea 0x[a-f0-9]+\(%rip\),%r11 # [a-f0-9]+ <bar>
[ ]*[a-f0-9]+: 48 8d 05 ([0-9a-f]{2} ){4} * lea 0x[a-f0-9]+\(%rip\),%rax # [a-f0-9]+ <__start_my_section>
[ ]*[a-f0-9]+: 4c 8d 1d ([0-9a-f]{2} ){4} * lea 0x[a-f0-9]+\(%rip\),%r11 # [a-f0-9]+ <__stop_my_section>
[ ]*[a-f0-9]+: 4c 8d 1d ([0-9a-f]{2} ){4} * lea 0x[a-f0-9]+\(%rip\),%r11 # [a-f0-9]+ <.*>
#pass

View File

@ -15,5 +15,5 @@ Disassembly of section .text:
[ ]*[a-f0-9]+: 48 8d 05 ([0-9a-f]{2} ){4} * lea -0x[a-f0-9]+\(%rip\),%rax # [a-f0-9]+ <foo>
[ ]*[a-f0-9]+: 4c 8d 1d ([0-9a-f]{2} ){4} * lea 0x[a-f0-9]+\(%rip\),%r11 # [a-f0-9]+ <bar>
[ ]*[a-f0-9]+: 48 8d 05 ([0-9a-f]{2} ){4} * lea 0x[a-f0-9]+\(%rip\),%rax # [a-f0-9]+ <__start_my_section>
[ ]*[a-f0-9]+: 4c 8d 1d ([0-9a-f]{2} ){4} * lea 0x[a-f0-9]+\(%rip\),%r11 # [a-f0-9]+ <__stop_my_section>
[ ]*[a-f0-9]+: 4c 8d 1d ([0-9a-f]{2} ){4} * lea 0x[a-f0-9]+\(%rip\),%r11 # [a-f0-9]+ <.*>
#pass

View File

@ -15,5 +15,5 @@ Disassembly of section .text:
[ ]*[a-f0-9]+: 48 8d 05 ([0-9a-f]{2} ){4} * lea -0x[a-f0-9]+\(%rip\),%rax # [a-f0-9]+ <foo>
[ ]*[a-f0-9]+: 4c 8d 1d ([0-9a-f]{2} ){4} * lea 0x[a-f0-9]+\(%rip\),%r11 # [a-f0-9]+ <bar>
[ ]*[a-f0-9]+: 48 8d 05 ([0-9a-f]{2} ){4} * lea 0x[a-f0-9]+\(%rip\),%rax # [a-f0-9]+ <__start_my_section>
[ ]*[a-f0-9]+: 4c 8d 1d ([0-9a-f]{2} ){4} * lea 0x[a-f0-9]+\(%rip\),%r11 # [a-f0-9]+ <__stop_my_section>
[ ]*[a-f0-9]+: 4c 8d 1d ([0-9a-f]{2} ){4} * lea 0x[a-f0-9]+\(%rip\),%r11 # [a-f0-9]+ <.*>
#pass