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When --gc-sections is in effect, a reference from a retained section to __start_SECNAME or __stop_SECNAME causes all input sections named SECNAME to also be retained, if SECNAME is representable as a C identifier and either __start_SECNAME or __stop_SECNAME is synthesized by the linker. Add an option to disable that feature, effectively ignoring any relocation that references a synthesized linker defined __start_ or __stop_ symbol. PR 27451 include/ * bfdlink.h (struct bfd_link_info): Add start_stop_gc. bfd/ * elflink.c (_bfd_elf_gc_mark_rsec): Ignore synthesized linker defined start/stop symbols when start_stop_gc. (bfd_elf_gc_mark_dynamic_ref_symbol): Likewise. (bfd_elf_define_start_stop): Don't modify ldscript_def syms. * linker.c (bfd_generic_define_start_stop): Likewise. ld/ * emultempl/elf.em: Handle -z start-stop-gc and -z nostart-stop-gc. * lexsup.c (elf_static_list_options): Display help for them. Move help for -z stack-size to here from elf_shlib_list_options. Add help for -z start-stop-visibility and -z undefs. * ld.texi: Document -z start-stop-gc and -z nostart-stop-gc. * NEWS: Mention -z start-stop-gc. * testsuite/ld-gc/start2.s, * testsuite/ld-gc/start2.d: New test. * testsuite/ld-gc/gc.exp: Run it.
1028 lines
36 KiB
C
1028 lines
36 KiB
C
/* bfdlink.h -- header file for BFD link routines
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Copyright (C) 1993-2021 Free Software Foundation, Inc.
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Written by Steve Chamberlain and Ian Lance Taylor, Cygnus Support.
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This file is part of BFD, the Binary File Descriptor library.
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 3 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program; if not, write to the Free Software
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Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston,
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MA 02110-1301, USA. */
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#ifndef BFDLINK_H
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#define BFDLINK_H
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/* Which symbols to strip during a link. */
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enum bfd_link_strip
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{
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strip_none, /* Don't strip any symbols. */
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strip_debugger, /* Strip debugging symbols. */
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strip_some, /* keep_hash is the list of symbols to keep. */
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strip_all /* Strip all symbols. */
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};
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/* Which local symbols to discard during a link. This is irrelevant
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if strip_all is used. */
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enum bfd_link_discard
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{
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discard_sec_merge, /* Discard local temporary symbols in SEC_MERGE
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sections. */
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discard_none, /* Don't discard any locals. */
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discard_l, /* Discard local temporary symbols. */
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discard_all /* Discard all locals. */
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};
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enum notice_asneeded_action {
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notice_as_needed,
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notice_not_needed,
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notice_needed
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};
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/* Whether to generate ELF common symbols with the STT_COMMON type
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during a relocatable link. */
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enum bfd_link_elf_stt_common
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{
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unchanged,
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elf_stt_common,
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no_elf_stt_common
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};
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/* Describes the type of hash table entry structure being used.
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Different hash table structure have different fields and so
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support different linking features. */
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enum bfd_link_hash_table_type
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{
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bfd_link_generic_hash_table,
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bfd_link_elf_hash_table
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};
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/* These are the possible types of an entry in the BFD link hash
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table. */
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enum bfd_link_hash_type
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{
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bfd_link_hash_new, /* Symbol is new. */
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bfd_link_hash_undefined, /* Symbol seen before, but undefined. */
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bfd_link_hash_undefweak, /* Symbol is weak and undefined. */
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bfd_link_hash_defined, /* Symbol is defined. */
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bfd_link_hash_defweak, /* Symbol is weak and defined. */
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bfd_link_hash_common, /* Symbol is common. */
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bfd_link_hash_indirect, /* Symbol is an indirect link. */
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bfd_link_hash_warning /* Like indirect, but warn if referenced. */
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};
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enum bfd_link_common_skip_ar_symbols
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{
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bfd_link_common_skip_none,
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bfd_link_common_skip_text,
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bfd_link_common_skip_data,
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bfd_link_common_skip_all
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};
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struct bfd_link_hash_common_entry
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{
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unsigned int alignment_power; /* Alignment. */
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asection *section; /* Symbol section. */
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};
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/* The linking routines use a hash table which uses this structure for
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its elements. */
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struct bfd_link_hash_entry
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{
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/* Base hash table entry structure. */
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struct bfd_hash_entry root;
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/* Type of this entry. */
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ENUM_BITFIELD (bfd_link_hash_type) type : 8;
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/* Symbol is referenced in a normal regular object file,
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as distinct from a LTO IR object file. */
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unsigned int non_ir_ref_regular : 1;
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/* Symbol is referenced in a normal dynamic object file,
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as distinct from a LTO IR object file. */
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unsigned int non_ir_ref_dynamic : 1;
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/* Symbol is a built-in define. These will be overridden by PROVIDE
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in a linker script. */
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unsigned int linker_def : 1;
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/* Symbol defined in a linker script. */
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unsigned int ldscript_def : 1;
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/* Symbol will be converted from absolute to section-relative. Set for
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symbols defined by a script from "dot" (also SEGMENT_START or ORIGIN)
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outside of an output section statement. */
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unsigned int rel_from_abs : 1;
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/* A union of information depending upon the type. */
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union
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{
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/* Nothing is kept for bfd_hash_new. */
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/* bfd_link_hash_undefined, bfd_link_hash_undefweak. */
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struct
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{
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/* Undefined and common symbols are kept in a linked list through
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this field. This field is present in all of the union element
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so that we don't need to remove entries from the list when we
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change their type. Removing entries would either require the
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list to be doubly linked, which would waste more memory, or
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require a traversal. When an undefined or common symbol is
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created, it should be added to this list, the head of which is in
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the link hash table itself. As symbols are defined, they need
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not be removed from the list; anything which reads the list must
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doublecheck the symbol type.
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Weak symbols are not kept on this list.
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Defined and defweak symbols use this field as a reference marker.
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If the field is not NULL, or this structure is the tail of the
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undefined symbol list, the symbol has been referenced. If the
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symbol is undefined and becomes defined, this field will
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automatically be non-NULL since the symbol will have been on the
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undefined symbol list. */
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struct bfd_link_hash_entry *next;
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/* BFD symbol was found in. */
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bfd *abfd;
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} undef;
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/* bfd_link_hash_defined, bfd_link_hash_defweak. */
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struct
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{
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struct bfd_link_hash_entry *next;
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/* Symbol section. */
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asection *section;
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/* Symbol value. */
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bfd_vma value;
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} def;
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/* bfd_link_hash_indirect, bfd_link_hash_warning. */
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struct
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{
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struct bfd_link_hash_entry *next;
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/* Real symbol. */
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struct bfd_link_hash_entry *link;
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/* Warning message (bfd_link_hash_warning only). */
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const char *warning;
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} i;
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/* bfd_link_hash_common. */
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struct
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{
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struct bfd_link_hash_entry *next;
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/* The linker needs to know three things about common
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symbols: the size, the alignment, and the section in
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which the symbol should be placed. We store the size
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here, and we allocate a small structure to hold the
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section and the alignment. The alignment is stored as a
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power of two. We don't store all the information
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directly because we don't want to increase the size of
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the union; this structure is a major space user in the
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linker. */
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struct bfd_link_hash_common_entry *p;
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/* Common symbol size. */
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bfd_size_type size;
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} c;
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} u;
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};
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/* This is the link hash table. It is a derived class of
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bfd_hash_table. */
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struct bfd_link_hash_table
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{
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/* The hash table itself. */
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struct bfd_hash_table table;
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/* A linked list of undefined and common symbols, linked through the
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next field in the bfd_link_hash_entry structure. */
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struct bfd_link_hash_entry *undefs;
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/* Entries are added to the tail of the undefs list. */
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struct bfd_link_hash_entry *undefs_tail;
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/* Function to free the hash table on closing BFD. */
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void (*hash_table_free) (bfd *);
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/* The type of the link hash table. */
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enum bfd_link_hash_table_type type;
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};
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/* Look up an entry in a link hash table. If FOLLOW is TRUE, this
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follows bfd_link_hash_indirect and bfd_link_hash_warning links to
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the real symbol. */
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extern struct bfd_link_hash_entry *bfd_link_hash_lookup
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(struct bfd_link_hash_table *, const char *, bfd_boolean create,
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bfd_boolean copy, bfd_boolean follow);
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/* Look up an entry in the main linker hash table if the symbol might
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be wrapped. This should only be used for references to an
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undefined symbol, not for definitions of a symbol. */
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extern struct bfd_link_hash_entry *bfd_wrapped_link_hash_lookup
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(bfd *, struct bfd_link_info *, const char *, bfd_boolean,
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bfd_boolean, bfd_boolean);
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/* If H is a wrapped symbol, ie. the symbol name starts with "__wrap_"
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and the remainder is found in wrap_hash, return the real symbol. */
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extern struct bfd_link_hash_entry *unwrap_hash_lookup
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(struct bfd_link_info *, bfd *, struct bfd_link_hash_entry *);
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/* Traverse a link hash table. */
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extern void bfd_link_hash_traverse
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(struct bfd_link_hash_table *,
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bfd_boolean (*) (struct bfd_link_hash_entry *, void *),
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void *);
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/* Add an entry to the undefs list. */
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extern void bfd_link_add_undef
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(struct bfd_link_hash_table *, struct bfd_link_hash_entry *);
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/* Remove symbols from the undefs list that don't belong there. */
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extern void bfd_link_repair_undef_list
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(struct bfd_link_hash_table *table);
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/* Read symbols and cache symbol pointer array in outsymbols. */
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extern bfd_boolean bfd_generic_link_read_symbols (bfd *);
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/* Check the relocs in the BFD. Called after all the input
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files have been loaded, and garbage collection has tagged
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any unneeded sections. */
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extern bfd_boolean bfd_link_check_relocs (bfd *,struct bfd_link_info *);
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struct bfd_sym_chain
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{
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struct bfd_sym_chain *next;
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const char *name;
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};
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/* How to handle unresolved symbols.
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There are four possibilities which are enumerated below: */
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enum report_method
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{
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/* This is the initial value when then link_info structure is created.
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It allows the various stages of the linker to determine whether they
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allowed to set the value. */
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RM_NOT_YET_SET = 0,
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RM_IGNORE,
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RM_DIAGNOSE,
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};
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/* How to handle DT_TEXTREL. */
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enum textrel_check_method
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{
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textrel_check_none,
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textrel_check_warning,
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textrel_check_error
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};
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#define bfd_link_textrel_check(info) \
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(info->textrel_check != textrel_check_none)
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typedef enum {with_flags, without_flags} flag_type;
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/* A section flag list. */
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struct flag_info_list
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{
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flag_type with;
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const char *name;
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bfd_boolean valid;
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struct flag_info_list *next;
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};
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/* Section flag info. */
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struct flag_info
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{
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flagword only_with_flags;
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flagword not_with_flags;
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struct flag_info_list *flag_list;
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bfd_boolean flags_initialized;
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};
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struct bfd_elf_dynamic_list;
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struct bfd_elf_version_tree;
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/* Types of output. */
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enum output_type
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{
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type_pde,
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type_pie,
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type_relocatable,
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type_dll,
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};
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#define bfd_link_pde(info) ((info)->type == type_pde)
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#define bfd_link_dll(info) ((info)->type == type_dll)
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#define bfd_link_relocatable(info) ((info)->type == type_relocatable)
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#define bfd_link_pie(info) ((info)->type == type_pie)
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#define bfd_link_executable(info) (bfd_link_pde (info) || bfd_link_pie (info))
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#define bfd_link_pic(info) (bfd_link_dll (info) || bfd_link_pie (info))
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/* This structure holds all the information needed to communicate
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between BFD and the linker when doing a link. */
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struct bfd_link_info
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{
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/* Output type. */
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ENUM_BITFIELD (output_type) type : 2;
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/* TRUE if BFD should pre-bind symbols in a shared object. */
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unsigned int symbolic: 1;
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/* TRUE if executable should not contain copy relocs.
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Setting this true may result in a non-sharable text segment. */
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unsigned int nocopyreloc: 1;
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/* TRUE if BFD should export all symbols in the dynamic symbol table
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of an executable, rather than only those used. */
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unsigned int export_dynamic: 1;
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/* TRUE if a default symbol version should be created and used for
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exported symbols. */
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unsigned int create_default_symver: 1;
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/* TRUE if unreferenced sections should be removed. */
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unsigned int gc_sections: 1;
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/* TRUE if exported symbols should be kept during section gc. */
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unsigned int gc_keep_exported: 1;
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/* TRUE if every symbol should be reported back via the notice
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callback. */
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unsigned int notice_all: 1;
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/* TRUE if the LTO plugin is active. */
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unsigned int lto_plugin_active: 1;
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/* TRUE if all LTO IR symbols have been read. */
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unsigned int lto_all_symbols_read : 1;
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/* TRUE if global symbols in discarded sections should be stripped. */
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unsigned int strip_discarded: 1;
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/* TRUE if all data symbols should be dynamic. */
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unsigned int dynamic_data: 1;
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/* TRUE if section groups should be resolved. */
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unsigned int resolve_section_groups: 1;
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/* Set if output file is big-endian, or if that is unknown, from
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the command line or first input file endianness. */
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unsigned int big_endian : 1;
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/* Which symbols to strip. */
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ENUM_BITFIELD (bfd_link_strip) strip : 2;
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/* Which local symbols to discard. */
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ENUM_BITFIELD (bfd_link_discard) discard : 2;
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/* Whether to generate ELF common symbols with the STT_COMMON type. */
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ENUM_BITFIELD (bfd_link_elf_stt_common) elf_stt_common : 2;
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/* Criteria for skipping symbols when determining
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whether to include an object from an archive. */
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ENUM_BITFIELD (bfd_link_common_skip_ar_symbols) common_skip_ar_symbols : 2;
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/* What to do with unresolved symbols in an object file.
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When producing executables the default is GENERATE_ERROR.
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When producing shared libraries the default is IGNORE. The
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assumption with shared libraries is that the reference will be
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resolved at load/execution time. */
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ENUM_BITFIELD (report_method) unresolved_syms_in_objects : 2;
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/* What to do with unresolved symbols in a shared library.
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The same defaults apply. */
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ENUM_BITFIELD (report_method) unresolved_syms_in_shared_libs : 2;
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|
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/* TRUE if unresolved symbols are to be warned, rather than errored. */
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unsigned int warn_unresolved_syms: 1;
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|
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/* TRUE if shared objects should be linked directly, not shared. */
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unsigned int static_link: 1;
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/* TRUE if symbols should be retained in memory, FALSE if they
|
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should be freed and reread. */
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unsigned int keep_memory: 1;
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|
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/* TRUE if BFD should generate relocation information in the final
|
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executable. */
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unsigned int emitrelocations: 1;
|
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|
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/* TRUE if PT_GNU_RELRO segment should be created. */
|
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unsigned int relro: 1;
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|
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/* TRUE if separate code segment should be created. */
|
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unsigned int separate_code: 1;
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/* Nonzero if .eh_frame_hdr section and PT_GNU_EH_FRAME ELF segment
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should be created. 1 for DWARF2 tables, 2 for compact tables. */
|
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unsigned int eh_frame_hdr_type: 2;
|
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|
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/* What to do with DT_TEXTREL in output. */
|
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ENUM_BITFIELD (textrel_check_method) textrel_check: 2;
|
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|
||
/* TRUE if .hash section should be created. */
|
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unsigned int emit_hash: 1;
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|
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/* TRUE if .gnu.hash section should be created. */
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unsigned int emit_gnu_hash: 1;
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|
||
/* If TRUE reduce memory overheads, at the expense of speed. This will
|
||
cause map file generation to use an O(N^2) algorithm and disable
|
||
caching ELF symbol buffer. */
|
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unsigned int reduce_memory_overheads: 1;
|
||
|
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/* TRUE if the output file should be in a traditional format. This
|
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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;
|
||
|
||
/* TRUE if non-PLT relocs should be merged into one reloc section
|
||
and sorted so that relocs against the same symbol come together. */
|
||
unsigned int combreloc: 1;
|
||
|
||
/* TRUE if a default symbol version should be created and used for
|
||
imported symbols. */
|
||
unsigned int default_imported_symver: 1;
|
||
|
||
/* TRUE if the new ELF dynamic tags are enabled. */
|
||
unsigned int new_dtags: 1;
|
||
|
||
/* FALSE if .eh_frame unwind info should be generated for PLT and other
|
||
linker created sections, TRUE if it should be omitted. */
|
||
unsigned int no_ld_generated_unwind_info: 1;
|
||
|
||
/* TRUE if BFD should generate a "task linked" object file,
|
||
similar to relocatable but also with globals converted to
|
||
statics. */
|
||
unsigned int task_link: 1;
|
||
|
||
/* TRUE if ok to have multiple definitions, without warning. */
|
||
unsigned int allow_multiple_definition: 1;
|
||
|
||
/* TRUE if multiple definition of absolute symbols (eg. from -R) should
|
||
be reported. */
|
||
unsigned int prohibit_multiple_definition_absolute: 1;
|
||
|
||
/* TRUE if multiple definitions should only warn. */
|
||
unsigned int warn_multiple_definition: 1;
|
||
|
||
/* TRUE if ok to have version with no definition. */
|
||
unsigned int allow_undefined_version: 1;
|
||
|
||
/* TRUE if some symbols have to be dynamic, controlled by
|
||
--dynamic-list command line options. */
|
||
unsigned int dynamic: 1;
|
||
|
||
/* TRUE if PT_GNU_STACK segment should be created with PF_R|PF_W|PF_X
|
||
flags. */
|
||
unsigned int execstack: 1;
|
||
|
||
/* TRUE if PT_GNU_STACK segment should be created with PF_R|PF_W
|
||
flags. */
|
||
unsigned int noexecstack: 1;
|
||
|
||
/* TRUE if we want to produced optimized output files. This might
|
||
need much more time and therefore must be explicitly selected. */
|
||
unsigned int optimize: 1;
|
||
|
||
/* TRUE if user should be informed of removed unreferenced sections. */
|
||
unsigned int print_gc_sections: 1;
|
||
|
||
/* TRUE if we should warn alternate ELF machine code. */
|
||
unsigned int warn_alternate_em: 1;
|
||
|
||
/* TRUE if the linker script contained an explicit PHDRS command. */
|
||
unsigned int user_phdrs: 1;
|
||
|
||
/* TRUE if program headers ought to be loaded. */
|
||
unsigned int load_phdrs: 1;
|
||
|
||
/* TRUE if we should check relocations after all input files have
|
||
been opened. */
|
||
unsigned int check_relocs_after_open_input: 1;
|
||
|
||
/* TRUE if generation of .interp/PT_INTERP should be suppressed. */
|
||
unsigned int nointerp: 1;
|
||
|
||
/* TRUE if common symbols should be treated as undefined. */
|
||
unsigned int inhibit_common_definition : 1;
|
||
|
||
/* TRUE if "-Map map" is passed to linker. */
|
||
unsigned int has_map_file : 1;
|
||
|
||
/* TRUE if "--enable-non-contiguous-regions" is passed to the
|
||
linker. */
|
||
unsigned int non_contiguous_regions : 1;
|
||
|
||
/* TRUE if "--enable-non-contiguous-regions-warnings" is passed to
|
||
the linker. */
|
||
unsigned int non_contiguous_regions_warnings : 1;
|
||
|
||
/* TRUE if all symbol names should be unique. */
|
||
unsigned int unique_symbol : 1;
|
||
|
||
/* Char that may appear as the first char of a symbol, but should be
|
||
skipped (like symbol_leading_char) when looking up symbols in
|
||
wrap_hash. Used by PowerPC Linux for 'dot' symbols. */
|
||
char wrap_char;
|
||
|
||
/* Separator between archive and filename in linker script filespecs. */
|
||
char path_separator;
|
||
|
||
/* Compress DWARF debug sections. */
|
||
enum compressed_debug_section_type compress_debug;
|
||
|
||
/* Default stack size. Zero means default (often zero itself), -1
|
||
means explicitly zero-sized. */
|
||
bfd_signed_vma stacksize;
|
||
|
||
/* Enable or disable target specific optimizations.
|
||
|
||
Not all targets have optimizations to enable.
|
||
|
||
Normally these optimizations are disabled by default but some targets
|
||
prefer to enable them by default. So this field is a tri-state variable.
|
||
The values are:
|
||
|
||
zero: Enable the optimizations (either from --relax being specified on
|
||
the command line or the backend's before_allocation emulation function.
|
||
|
||
positive: The user has requested that these optimizations be disabled.
|
||
(Via the --no-relax command line option).
|
||
|
||
negative: The optimizations are disabled. (Set when initializing the
|
||
args_type structure in ldmain.c:main. */
|
||
signed int disable_target_specific_optimizations;
|
||
|
||
/* Function callbacks. */
|
||
const struct bfd_link_callbacks *callbacks;
|
||
|
||
/* Hash table handled by BFD. */
|
||
struct bfd_link_hash_table *hash;
|
||
|
||
/* Hash table of symbols to keep. This is NULL unless strip is
|
||
strip_some. */
|
||
struct bfd_hash_table *keep_hash;
|
||
|
||
/* Hash table of symbols to report back via the notice callback. If
|
||
this is NULL, and notice_all is FALSE, then no symbols are
|
||
reported back. */
|
||
struct bfd_hash_table *notice_hash;
|
||
|
||
/* Hash table of symbols which are being wrapped (the --wrap linker
|
||
option). If this is NULL, no symbols are being wrapped. */
|
||
struct bfd_hash_table *wrap_hash;
|
||
|
||
/* Hash table of symbols which may be left unresolved during
|
||
a link. If this is NULL, no symbols can be left unresolved. */
|
||
struct bfd_hash_table *ignore_hash;
|
||
|
||
/* The output BFD. */
|
||
bfd *output_bfd;
|
||
|
||
/* The import library generated. */
|
||
bfd *out_implib_bfd;
|
||
|
||
/* The list of input BFD's involved in the link. These are chained
|
||
together via the link.next field. */
|
||
bfd *input_bfds;
|
||
bfd **input_bfds_tail;
|
||
|
||
/* If a symbol should be created for each input BFD, this is section
|
||
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;
|
||
|
||
/* List of global symbol names that are starting points for marking
|
||
sections against garbage collection. */
|
||
struct bfd_sym_chain *gc_sym_list;
|
||
|
||
/* If a base output file is wanted, then this points to it */
|
||
void *base_file;
|
||
|
||
/* The function to call when the executable or shared object is
|
||
loaded. */
|
||
const char *init_function;
|
||
|
||
/* The function to call when the executable or shared object is
|
||
unloaded. */
|
||
const char *fini_function;
|
||
|
||
/* Number of relaxation passes. Usually only one relaxation pass
|
||
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;
|
||
|
||
/* Number of relaxation trips. This number is incremented every
|
||
time the relaxation pass is restarted due to a previous
|
||
relaxation returning true in *AGAIN. */
|
||
int relax_trip;
|
||
|
||
/* > 0 to treat protected data defined in the shared library as
|
||
reference external. 0 to treat it as internal. -1 to let
|
||
backend to decide. */
|
||
int extern_protected_data;
|
||
|
||
/* 1 to make undefined weak symbols dynamic when building a dynamic
|
||
object. 0 to resolve undefined weak symbols to zero. -1 to let
|
||
the backend decide. */
|
||
int dynamic_undefined_weak;
|
||
|
||
/* Non-zero if auto-import thunks for DATA items in pei386 DLLs
|
||
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;
|
||
|
||
/* Non-zero if runtime relocs for DATA items with non-zero addends
|
||
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;
|
||
|
||
/* How many spare .dynamic DT_NULL entries should be added? */
|
||
unsigned int spare_dynamic_tags;
|
||
|
||
/* May be used to set DT_FLAGS for ELF. */
|
||
bfd_vma flags;
|
||
|
||
/* May be used to set DT_FLAGS_1 for ELF. */
|
||
bfd_vma flags_1;
|
||
|
||
/* May be used to set DT_GNU_FLAGS_1 for ELF. */
|
||
bfd_vma gnu_flags_1;
|
||
|
||
/* TRUE if references to __start_/__stop_ synthesized symbols do not
|
||
specially retain C identifier named sections. */
|
||
int start_stop_gc;
|
||
|
||
/* May be used to set ELF visibility for __start_* / __stop_. */
|
||
unsigned int start_stop_visibility;
|
||
|
||
/* The maximum page size for ELF. */
|
||
bfd_vma maxpagesize;
|
||
|
||
/* The common page size for ELF. */
|
||
bfd_vma commonpagesize;
|
||
|
||
/* Start and end of RELRO region. */
|
||
bfd_vma relro_start, relro_end;
|
||
|
||
/* List of symbols should be dynamic. */
|
||
struct bfd_elf_dynamic_list *dynamic_list;
|
||
|
||
/* The version information. */
|
||
struct bfd_elf_version_tree *version_info;
|
||
};
|
||
|
||
/* Some forward-definitions used by some callbacks. */
|
||
|
||
struct elf_strtab_hash;
|
||
struct elf_internal_sym;
|
||
|
||
/* This structures holds a set of callback functions. These are called
|
||
by the BFD linker routines. */
|
||
|
||
struct bfd_link_callbacks
|
||
{
|
||
/* A function which is called when an object is added from an
|
||
archive. ABFD is the archive element being added. NAME is the
|
||
name of the symbol which caused the archive element to be pulled
|
||
in. This function may set *SUBSBFD to point to an alternative
|
||
BFD from which symbols should in fact be added in place of the
|
||
original BFD's symbols. Returns TRUE if the object should be
|
||
added, FALSE if it should be skipped. */
|
||
bfd_boolean (*add_archive_element)
|
||
(struct bfd_link_info *, bfd *abfd, const char *name, bfd **subsbfd);
|
||
/* A function which is called when a symbol is found with multiple
|
||
definitions. H is the symbol which is defined multiple times.
|
||
NBFD is the new BFD, NSEC is the new section, and NVAL is the new
|
||
value. NSEC may be bfd_com_section or bfd_ind_section. */
|
||
void (*multiple_definition)
|
||
(struct bfd_link_info *, struct bfd_link_hash_entry *h,
|
||
bfd *nbfd, asection *nsec, bfd_vma nval);
|
||
/* A function which is called when a common symbol is defined
|
||
multiple times. H is the symbol appearing multiple times.
|
||
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. */
|
||
void (*multiple_common)
|
||
(struct bfd_link_info *, struct bfd_link_hash_entry *h,
|
||
bfd *nbfd, enum bfd_link_hash_type ntype, bfd_vma nsize);
|
||
/* A function which is called to add a symbol to a set. ENTRY is
|
||
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. */
|
||
void (*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);
|
||
/* A function which is called when the name of a g++ constructor or
|
||
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. */
|
||
void (*constructor)
|
||
(struct bfd_link_info *, bfd_boolean constructor, const char *name,
|
||
bfd *abfd, asection *sec, bfd_vma value);
|
||
/* A function which is called to issue a linker warning. For
|
||
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. */
|
||
void (*warning)
|
||
(struct bfd_link_info *, const char *warning, const char *symbol,
|
||
bfd *abfd, asection *section, bfd_vma address);
|
||
/* A function which is called when a relocation is attempted against
|
||
an undefined symbol. NAME is the symbol which is undefined.
|
||
ABFD, SECTION and ADDRESS identify the location from which the
|
||
reference is made. IS_FATAL indicates whether an undefined symbol is
|
||
a fatal error or not. In some cases SECTION may be NULL. */
|
||
void (*undefined_symbol)
|
||
(struct bfd_link_info *, const char *name, bfd *abfd,
|
||
asection *section, bfd_vma address, bfd_boolean is_fatal);
|
||
/* A function which is called when a reloc overflow occurs. ENTRY is
|
||
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. */
|
||
void (*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);
|
||
/* A function which is called when a dangerous reloc is performed.
|
||
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. */
|
||
void (*reloc_dangerous)
|
||
(struct bfd_link_info *, const char *message,
|
||
bfd *abfd, asection *section, bfd_vma address);
|
||
/* A function which is called when a reloc is found to be attached
|
||
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. */
|
||
void (*unattached_reloc)
|
||
(struct bfd_link_info *, const char *name,
|
||
bfd *abfd, asection *section, bfd_vma address);
|
||
/* A function which is called when a symbol in notice_hash is
|
||
defined or referenced. H is the symbol, INH the indirect symbol
|
||
if applicable. ABFD, SECTION and ADDRESS are the (new) value of
|
||
the symbol. If SECTION is bfd_und_section, this is a reference.
|
||
FLAGS are the symbol BSF_* flags. */
|
||
bfd_boolean (*notice)
|
||
(struct bfd_link_info *, struct bfd_link_hash_entry *h,
|
||
struct bfd_link_hash_entry *inh,
|
||
bfd *abfd, asection *section, bfd_vma address, flagword flags);
|
||
/* Error or warning link info message. */
|
||
void (*einfo)
|
||
(const char *fmt, ...);
|
||
/* General link info message. */
|
||
void (*info)
|
||
(const char *fmt, ...);
|
||
/* Message to be printed in linker map file. */
|
||
void (*minfo)
|
||
(const char *fmt, ...);
|
||
/* This callback provides a chance for users of the BFD library to
|
||
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);
|
||
/* This callback provides a chance for callers of the BFD to examine the
|
||
ELF (dynamic) string table once it is complete. */
|
||
void (*examine_strtab)
|
||
(struct elf_strtab_hash *symstrtab);
|
||
/* This callback is called just before a symbol is swapped out, so that the
|
||
CTF machinery can look up symbols during construction. The name is
|
||
already an external strtab offset at this point. */
|
||
void (*ctf_new_symbol)
|
||
(int symidx, struct elf_internal_sym *sym);
|
||
/* Likewise, for dynamic symbols. */
|
||
void (*ctf_new_dynsym)
|
||
(int symidx, struct elf_internal_sym *sym);
|
||
/* This callback should emit the CTF section into a non-loadable section in
|
||
the output BFD named .ctf or a name beginning with ".ctf.". */
|
||
void (*emit_ctf)
|
||
(void);
|
||
};
|
||
|
||
/* The linker builds link_order structures which tell the code how to
|
||
include input data in the output file. */
|
||
|
||
/* These are the types of link_order structures. */
|
||
|
||
enum bfd_link_order_type
|
||
{
|
||
bfd_undefined_link_order, /* Undefined. */
|
||
bfd_indirect_link_order, /* Built from a section. */
|
||
bfd_data_link_order, /* Set to explicit data. */
|
||
bfd_section_reloc_link_order, /* Relocate against a section. */
|
||
bfd_symbol_reloc_link_order /* Relocate against a symbol. */
|
||
};
|
||
|
||
/* This is the link_order structure itself. These form a chain
|
||
attached to the output section whose contents they are describing. */
|
||
|
||
struct bfd_link_order
|
||
{
|
||
/* Next link_order in chain. */
|
||
struct bfd_link_order *next;
|
||
/* Type of link_order. */
|
||
enum bfd_link_order_type type;
|
||
/* Offset within output section in bytes. */
|
||
bfd_vma offset;
|
||
/* Size within output section in octets. */
|
||
bfd_size_type size;
|
||
/* Type specific information. */
|
||
union
|
||
{
|
||
struct
|
||
{
|
||
/* Section to include. If this is used, then
|
||
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
|
||
{
|
||
/* Size of contents, or zero when contents should be filled by
|
||
the architecture-dependent fill function.
|
||
A non-zero value allows filling of the output section
|
||
with an arbitrary repeated pattern. */
|
||
unsigned int size;
|
||
/* Data to put into file. */
|
||
bfd_byte *contents;
|
||
} data;
|
||
struct
|
||
{
|
||
/* Description of reloc to generate. Used for
|
||
bfd_section_reloc_link_order and
|
||
bfd_symbol_reloc_link_order. */
|
||
struct bfd_link_order_reloc *p;
|
||
} reloc;
|
||
} u;
|
||
};
|
||
|
||
/* A linker order of type bfd_section_reloc_link_order or
|
||
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
|
||
{
|
||
/* Reloc type. */
|
||
bfd_reloc_code_real_type reloc;
|
||
|
||
union
|
||
{
|
||
/* For type bfd_section_reloc_link_order, this is the section
|
||
the reloc should be against. This must be a section in the
|
||
output BFD, not any of the input BFDs. */
|
||
asection *section;
|
||
/* For type bfd_symbol_reloc_link_order, this is the name of the
|
||
symbol the reloc should be against. */
|
||
const char *name;
|
||
} u;
|
||
|
||
/* Addend to use. The object file should contain zero. The BFD
|
||
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;
|
||
};
|
||
|
||
/* Allocate a new link_order for a section. */
|
||
extern struct bfd_link_order *bfd_new_link_order (bfd *, asection *);
|
||
|
||
struct bfd_section_already_linked;
|
||
|
||
extern bfd_boolean bfd_section_already_linked_table_init (void);
|
||
extern void bfd_section_already_linked_table_free (void);
|
||
extern bfd_boolean _bfd_handle_already_linked
|
||
(struct bfd_section *, struct bfd_section_already_linked *,
|
||
struct bfd_link_info *);
|
||
|
||
extern struct bfd_section *_bfd_nearby_section
|
||
(bfd *, struct bfd_section *, bfd_vma);
|
||
|
||
extern void _bfd_fix_excluded_sec_syms
|
||
(bfd *, struct bfd_link_info *);
|
||
|
||
/* These structures are used to describe version information for the
|
||
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. */
|
||
|
||
/* Glob pattern for a version. */
|
||
|
||
struct bfd_elf_version_expr
|
||
{
|
||
/* Next glob pattern for this version. */
|
||
struct bfd_elf_version_expr *next;
|
||
/* Glob pattern. */
|
||
const char *pattern;
|
||
/* Set if pattern is not a glob. */
|
||
unsigned int literal : 1;
|
||
/* Defined by ".symver". */
|
||
unsigned int symver : 1;
|
||
/* Defined by version script. */
|
||
unsigned int script : 1;
|
||
/* Pattern type. */
|
||
#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
|
||
{
|
||
/* List of all patterns, both wildcards and non-wildcards. */
|
||
struct bfd_elf_version_expr *list;
|
||
/* Hash table for non-wildcards. */
|
||
void *htab;
|
||
/* Remaining patterns. */
|
||
struct bfd_elf_version_expr *remaining;
|
||
/* What kind of pattern types are present in list (bitmask). */
|
||
unsigned int mask;
|
||
};
|
||
|
||
/* Version dependencies. */
|
||
|
||
struct bfd_elf_version_deps
|
||
{
|
||
/* Next dependency for this version. */
|
||
struct bfd_elf_version_deps *next;
|
||
/* The version which this version depends upon. */
|
||
struct bfd_elf_version_tree *version_needed;
|
||
};
|
||
|
||
/* A node in the version tree. */
|
||
|
||
struct bfd_elf_version_tree
|
||
{
|
||
/* Next version. */
|
||
struct bfd_elf_version_tree *next;
|
||
/* Name of this version. */
|
||
const char *name;
|
||
/* Version number. */
|
||
unsigned int vernum;
|
||
/* Regular expressions for global symbols in this version. */
|
||
struct bfd_elf_version_expr_head globals;
|
||
/* Regular expressions for local symbols in this version. */
|
||
struct bfd_elf_version_expr_head locals;
|
||
/* List of versions which this version depends upon. */
|
||
struct bfd_elf_version_deps *deps;
|
||
/* Index of the version name. This is used within BFD. */
|
||
unsigned int name_indx;
|
||
/* Whether this version tree was used. This is used within BFD. */
|
||
int used;
|
||
/* Matching hook. */
|
||
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
|