Copyright 1993, 1994, 1995, 1996, 1997, 1998, 1999, 2000, 2001, 2002,
2003, 2004, 2005, 2006, 2007, 2008 Free Software Foundation, Inc.
Written by Steve Chamberlain and Ian Lance Taylor, Cygnus Support.
This file is part of BFD, the Binary File Descriptor library.
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 3 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston,
MA 02110-1301, USA. */
#ifndef BFDLINK_H
#define BFDLINK_H
enum bfd_link_strip
{
strip_none,
strip_debugger,
strip_some,
strip_all
};
if strip_all is used. */
enum bfd_link_discard
{
discard_sec_merge,
sections. */
discard_none,
discard_l,
discard_all
};
Different hash table structure have different fields and so
support different linking features. */
enum bfd_link_hash_table_type
{
bfd_link_generic_hash_table,
bfd_link_elf_hash_table
};
table. */
enum bfd_link_hash_type
{
bfd_link_hash_new,
bfd_link_hash_undefined,
bfd_link_hash_undefweak,
bfd_link_hash_defined,
bfd_link_hash_defweak,
bfd_link_hash_common,
bfd_link_hash_indirect,
bfd_link_hash_warning
};
enum bfd_link_common_skip_ar_aymbols
{
bfd_link_common_skip_none,
bfd_link_common_skip_text,
bfd_link_common_skip_data,
bfd_link_common_skip_all
};
its elements. */
struct bfd_link_hash_entry
{
struct bfd_hash_entry root;
enum bfd_link_hash_type type;
union
{
struct
{
this field. This field is present in all of the union element
so that we don't need to remove entries from the list when we
change their type. Removing entries would either require the
list to be doubly linked, which would waste more memory, or
require a traversal. When an undefined or common symbol is
created, it should be added to this list, the head of which is in
the link hash table itself. As symbols are defined, they need
not be removed from the list; anything which reads the list must
doublecheck the symbol type.
Weak symbols are not kept on this list.
Defined and defweak symbols use this field as a reference marker.
If the field is not NULL, or this structure is the tail of the
undefined symbol list, the symbol has been referenced. If the
symbol is undefined and becomes defined, this field will
automatically be non-NULL since the symbol will have been on the
undefined symbol list. */
struct bfd_link_hash_entry *next;
bfd *abfd;
bfd *weak;
} undef;
struct
{
struct bfd_link_hash_entry *next;
asection *section;
bfd_vma value;
} def;
struct
{
struct bfd_link_hash_entry *next;
struct bfd_link_hash_entry *link;
const char *warning;
} i;
struct
{
struct bfd_link_hash_entry *next;
symbols: the size, the alignment, and the section in
which the symbol should be placed. We store the size
here, and we allocate a small structure to hold the
section and the alignment. The alignment is stored as a
power of two. We don't store all the information
directly because we don't want to increase the size of
the union; this structure is a major space user in the
linker. */
struct bfd_link_hash_common_entry
{
unsigned int alignment_power;
asection *section;
} *p;
bfd_size_type size;
} c;
} u;
};
bfd_hash_table. */
struct bfd_link_hash_table
{
struct bfd_hash_table table;
next field in the bfd_link_hash_entry structure. */
struct bfd_link_hash_entry *undefs;
struct bfd_link_hash_entry *undefs_tail;
enum bfd_link_hash_table_type type;
};
follows bfd_link_hash_indirect and bfd_link_hash_warning links to
the real symbol. */
extern struct bfd_link_hash_entry *bfd_link_hash_lookup
(struct bfd_link_hash_table *, const char *, bfd_boolean create,
bfd_boolean copy, bfd_boolean follow);
be wrapped. This should only be used for references to an
undefined symbol, not for definitions of a symbol. */
extern struct bfd_link_hash_entry *bfd_wrapped_link_hash_lookup
(bfd *, struct bfd_link_info *, const char *, bfd_boolean,
bfd_boolean, bfd_boolean);
extern void bfd_link_hash_traverse
(struct bfd_link_hash_table *,
bfd_boolean (*) (struct bfd_link_hash_entry *, void *),
void *);
extern void bfd_link_add_undef
(struct bfd_link_hash_table *, struct bfd_link_hash_entry *);
extern void bfd_link_repair_undef_list
(struct bfd_link_hash_table *table);
extern bfd_boolean bfd_generic_link_read_symbols (bfd *);
struct bfd_sym_chain
{
struct bfd_sym_chain *next;
const char *name;
};
There are four possibilities which are enumerated below: */
enum report_method
{
It allows the various stages of the linker to determine whether they
allowed to set the value. */
RM_NOT_YET_SET = 0,
RM_IGNORE,
RM_GENERATE_WARNING,
RM_GENERATE_ERROR
};
struct bfd_elf_dynamic_list;
between BFD and the linker when doing a link. */
struct bfd_link_info
{
unsigned int relocatable: 1;
executable. */
unsigned int emitrelocations: 1;
similar to relocatable but also with globals converted to
statics. */
unsigned int task_link: 1;
unsigned int shared: 1;
unsigned int symbolic: 1;
of an executable, rather than only those used. */
unsigned int export_dynamic: 1;
unsigned int static_link: 1;
is equivalent to the setting of the BFD_TRADITIONAL_FORMAT flag
on the output file, but may be checked when reading the input
files. */
unsigned int traditional_format: 1;
need much more time and therefore must be explicitly selected. */
unsigned int optimize: 1;
unsigned int allow_multiple_definition: 1;
unsigned int allow_undefined_version: 1;
exported symbols. */
unsigned int create_default_symver: 1;
imported symbols. */
unsigned int default_imported_symver: 1;
should be freed and reread. */
unsigned int keep_memory: 1;
callback. */
unsigned int notice_all: 1;
Setting this true may result in a non-sharable text segment. */
unsigned int nocopyreloc: 1;
unsigned int new_dtags: 1;
and sorted so that relocs against the same symbol come together. */
unsigned int combreloc: 1;
should be created. */
unsigned int eh_frame_hdr: 1;
unsigned int strip_discarded: 1;
unsigned int pie: 1;
unsigned int executable : 1;
flags. */
unsigned int execstack: 1;
flags. */
unsigned int noexecstack: 1;
unsigned int relro: 1;
unsigned int warn_shared_textrel: 1;
unsigned int gc_sections: 1;
unsigned int print_gc_sections: 1;
unsigned int emit_hash: 1;
unsigned int emit_gnu_hash: 1;
cause map file generation to use an O(N^2) algorithm and disable
caching ELF symbol buffer. */
unsigned int reduce_memory_overheads: 1;
unsigned int dynamic_data: 1;
--dynamic-list command line options. */
unsigned int dynamic: 1;
char *emit_note_gnu_build_id;
When producing executables the default is GENERATE_ERROR.
When producing shared libraries the default is IGNORE. The
assumption with shared libraries is that the reference will be
resolved at load/execution time. */
enum report_method unresolved_syms_in_objects;
The same defaults apply. */
enum report_method unresolved_syms_in_shared_libs;
enum bfd_link_strip strip;
enum bfd_link_discard discard;
whether to include an object from an archive. */
enum bfd_link_common_skip_ar_aymbols common_skip_ar_aymbols;
skipped (like symbol_leading_char) when looking up symbols in
wrap_hash. Used by PowerPC Linux for 'dot' symbols. */
char wrap_char;
char path_separator;
const struct bfd_link_callbacks *callbacks;
struct bfd_link_hash_table *hash;
strip_some. */
struct bfd_hash_table *keep_hash;
this is NULL, and notice_all is FALSE, then no symbols are
reported back. */
struct bfd_hash_table *notice_hash;
option). If this is NULL, no symbols are being wrapped. */
struct bfd_hash_table *wrap_hash;
bfd *output_bfd;
together via the link_next field. */
bfd *input_bfds;
bfd **input_bfds_tail;
where those symbols should be placed. It must be a section in
the output BFD. It may be NULL, in which case no such symbols
will be created. This is to support CREATE_OBJECT_SYMBOLS in the
linker command language. */
asection *create_object_symbols_section;
sections against garbage collection. */
struct bfd_sym_chain *gc_sym_list;
void *base_file;
loaded. */
const char *init_function;
unloaded. */
const char *fini_function;
is needed. But a backend can have as many relaxation passes as
necessary. During bfd_relax_section call, it is set to the
current pass, starting from 0. */
int relax_pass;
time the relaxation pass is restarted due to a previous
relaxation returning true in *AGAIN. */
int relax_trip;
should be generated/linked against. Set to 1 if this feature
is explicitly requested by the user, -1 if enabled by default. */
int pei386_auto_import;
in pei386 DLLs should be generated. Set to 1 if this feature
is explicitly requested by the user, -1 if enabled by default. */
int pei386_runtime_pseudo_reloc;
unsigned int spare_dynamic_tags;
bfd_vma flags;
bfd_vma flags_1;
bfd_vma relro_start, relro_end;
struct bfd_elf_dynamic_list *dynamic_list;
};
by the BFD linker routines. Except for the info functions, the first
argument to each callback function is the bfd_link_info structure
being used and each function returns a boolean value. If the
function returns FALSE, then the BFD function which called it should
return with a failure indication. */
struct bfd_link_callbacks
{
archive. ABFD is the archive element being added. NAME is the
name of the symbol which caused the archive element to be pulled
in. */
bfd_boolean (*add_archive_element)
(struct bfd_link_info *, bfd *abfd, const char *name);
definitions. NAME is the symbol which is defined multiple times.
OBFD is the old BFD, OSEC is the old section, OVAL is the old
value, NBFD is the new BFD, NSEC is the new section, and NVAL is
the new value. OBFD may be NULL. OSEC and NSEC may be
bfd_com_section or bfd_ind_section. */
bfd_boolean (*multiple_definition)
(struct bfd_link_info *, const char *name,
bfd *obfd, asection *osec, bfd_vma oval,
bfd *nbfd, asection *nsec, bfd_vma nval);
multiple times. NAME is the symbol appearing multiple times.
OBFD is the BFD of the existing symbol; it may be NULL if this is
not known. OTYPE is the type of the existing symbol, which may
be bfd_link_hash_defined, bfd_link_hash_defweak,
bfd_link_hash_common, or bfd_link_hash_indirect. If OTYPE is
bfd_link_hash_common, OSIZE is the size of the existing symbol.
NBFD is the BFD of the new symbol. NTYPE is the type of the new
symbol, one of bfd_link_hash_defined, bfd_link_hash_common, or
bfd_link_hash_indirect. If NTYPE is bfd_link_hash_common, NSIZE
is the size of the new symbol. */
bfd_boolean (*multiple_common)
(struct bfd_link_info *, const char *name,
bfd *obfd, enum bfd_link_hash_type otype, bfd_vma osize,
bfd *nbfd, enum bfd_link_hash_type ntype, bfd_vma nsize);
the link hash table entry for the set itself (e.g.,
__CTOR_LIST__). RELOC is the relocation to use for an entry in
the set when generating a relocatable file, and is also used to
get the size of the entry when generating an executable file.
ABFD, SEC and VALUE identify the value to add to the set. */
bfd_boolean (*add_to_set)
(struct bfd_link_info *, struct bfd_link_hash_entry *entry,
bfd_reloc_code_real_type reloc, bfd *abfd, asection *sec, bfd_vma value);
destructor is found. This is only called by some object file
formats. CONSTRUCTOR is TRUE for a constructor, FALSE for a
destructor. This will use BFD_RELOC_CTOR when generating a
relocatable file. NAME is the name of the symbol found. ABFD,
SECTION and VALUE are the value of the symbol. */
bfd_boolean (*constructor)
(struct bfd_link_info *, bfd_boolean constructor, const char *name,
bfd *abfd, asection *sec, bfd_vma value);
example, this is called when there is a reference to a warning
symbol. WARNING is the warning to be issued. SYMBOL is the name
of the symbol which triggered the warning; it may be NULL if
there is none. ABFD, SECTION and ADDRESS identify the location
which trigerred the warning; either ABFD or SECTION or both may
be NULL if the location is not known. */
bfd_boolean (*warning)
(struct bfd_link_info *, const char *warning, const char *symbol,
bfd *abfd, asection *section, bfd_vma address);
an undefined symbol. NAME is the symbol which is undefined.
ABFD, SECTION and ADDRESS identify the location from which the
reference is made. FATAL indicates whether an undefined symbol is
a fatal error or not. In some cases SECTION may be NULL. */
bfd_boolean (*undefined_symbol)
(struct bfd_link_info *, const char *name, bfd *abfd,
asection *section, bfd_vma address, bfd_boolean fatal);
the link hash table entry for the symbol the reloc is against.
NAME is the name of the local symbol or section the reloc is
against, RELOC_NAME is the name of the relocation, and ADDEND is
any addend that is used. ABFD, SECTION and ADDRESS identify the
location at which the overflow occurs; if this is the result of a
bfd_section_reloc_link_order or bfd_symbol_reloc_link_order, then
ABFD will be NULL. */
bfd_boolean (*reloc_overflow)
(struct bfd_link_info *, struct bfd_link_hash_entry *entry,
const char *name, const char *reloc_name, bfd_vma addend,
bfd *abfd, asection *section, bfd_vma address);
MESSAGE is an appropriate message.
ABFD, SECTION and ADDRESS identify the location at which the
problem occurred; if this is the result of a
bfd_section_reloc_link_order or bfd_symbol_reloc_link_order, then
ABFD will be NULL. */
bfd_boolean (*reloc_dangerous)
(struct bfd_link_info *, const char *message,
bfd *abfd, asection *section, bfd_vma address);
to a symbol which is not being written out. NAME is the name of
the symbol. ABFD, SECTION and ADDRESS identify the location of
the reloc; if this is the result of a
bfd_section_reloc_link_order or bfd_symbol_reloc_link_order, then
ABFD will be NULL. */
bfd_boolean (*unattached_reloc)
(struct bfd_link_info *, const char *name,
bfd *abfd, asection *section, bfd_vma address);
defined or referenced. NAME is the symbol. ABFD, SECTION and
ADDRESS are the value of the symbol. If SECTION is
bfd_und_section, this is a reference. */
bfd_boolean (*notice)
(struct bfd_link_info *, const char *name,
bfd *abfd, asection *section, bfd_vma address);
void (*einfo)
(const char *fmt, ...);
void (*info)
(const char *fmt, ...);
void (*minfo)
(const char *fmt, ...);
override its decision about whether to place two adjacent sections
into the same segment. */
bfd_boolean (*override_segment_assignment)
(struct bfd_link_info *, bfd * abfd,
asection * current_section, asection * previous_section,
bfd_boolean new_segment);
};
include input data in the output file. */
enum bfd_link_order_type
{
bfd_undefined_link_order,
bfd_indirect_link_order,
bfd_data_link_order,
bfd_section_reloc_link_order,
bfd_symbol_reloc_link_order
};
attached to the output section whose contents they are describing. */
struct bfd_link_order
{
struct bfd_link_order *next;
enum bfd_link_order_type type;
bfd_vma offset;
bfd_size_type size;
union
{
struct
{
section->output_section must be the section the
link_order is attached to, section->output_offset must
equal the link_order offset field, and section->size
must equal the link_order size field. Maybe these
restrictions should be relaxed someday. */
asection *section;
} indirect;
struct
{
within output section.
A non-zero value allows filling of the output section
with an arbitrary repeated pattern. */
unsigned int size;
bfd_byte *contents;
} data;
struct
{
bfd_section_reloc_link_order and
bfd_symbol_reloc_link_order. */
struct bfd_link_order_reloc *p;
} reloc;
} u;
};
bfd_symbol_reloc_link_order means to create a reloc against a
section or symbol, respectively. This is used to implement -Ur to
generate relocs for the constructor tables. The
bfd_link_order_reloc structure describes the reloc that BFD should
create. It is similar to a arelent, but I didn't use arelent
because the linker does not know anything about most symbols, and
any asymbol structure it creates will be partially meaningless.
This information could logically be in the bfd_link_order struct,
but I didn't want to waste the space since these types of relocs
are relatively rare. */
struct bfd_link_order_reloc
{
bfd_reloc_code_real_type reloc;
union
{
the reloc should be against. This must be a section in the
output BFD, not any of the input BFDs. */
asection *section;
symbol the reloc should be against. */
const char *name;
} u;
backend is responsible for filling in the contents of the object
file correctly. For some object file formats (e.g., COFF) the
addend must be stored into in the object file, and for some
(e.g., SPARC a.out) it is kept in the reloc. */
bfd_vma addend;
};
extern struct bfd_link_order *bfd_new_link_order (bfd *, asection *);
ELF linker. These structures could be manipulated entirely inside
BFD, but it would be a pain. Instead, the regular linker sets up
these structures, and then passes them into BFD. */
struct bfd_elf_version_expr
{
struct bfd_elf_version_expr *next;
const char *pattern;
const char *symbol;
unsigned int symver : 1;
unsigned int script : 1;
#define BFD_ELF_VERSION_C_TYPE 1
#define BFD_ELF_VERSION_CXX_TYPE 2
#define BFD_ELF_VERSION_JAVA_TYPE 4
unsigned int mask : 3;
};
struct bfd_elf_version_expr_head
{
struct bfd_elf_version_expr *list;
void *htab;
struct bfd_elf_version_expr *remaining;
unsigned int mask;
};
struct bfd_elf_version_deps
{
struct bfd_elf_version_deps *next;
struct bfd_elf_version_tree *version_needed;
};
struct bfd_elf_version_tree
{
struct bfd_elf_version_tree *next;
const char *name;
unsigned int vernum;
struct bfd_elf_version_expr_head globals;
struct bfd_elf_version_expr_head locals;
struct bfd_elf_version_deps *deps;
unsigned int name_indx;
int used;
struct bfd_elf_version_expr *(*match)
(struct bfd_elf_version_expr_head *head,
struct bfd_elf_version_expr *prev, const char *sym);
};
struct bfd_elf_dynamic_list
{
struct bfd_elf_version_expr_head head;
struct bfd_elf_version_expr *(*match)
(struct bfd_elf_version_expr_head *head,
struct bfd_elf_version_expr *prev, const char *sym);
};
#endif
