484 lines
15 KiB
C
484 lines
15 KiB
C
/* plugin-api.h -- External linker plugin API. */
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/* Copyright (C) 2009-2020 Free Software Foundation, Inc.
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Written by Cary Coutant <ccoutant@google.com>.
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This file is part of binutils.
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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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/* This file defines the interface for writing a linker plugin, which is
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described at < http://gcc.gnu.org/wiki/whopr/driver >. */
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#ifndef PLUGIN_API_H
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#define PLUGIN_API_H
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#ifdef HAVE_STDINT_H
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#include <stdint.h>
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#elif defined(HAVE_INTTYPES_H)
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#include <inttypes.h>
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#endif
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#include <sys/types.h>
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#if !defined(HAVE_STDINT_H) && !defined(HAVE_INTTYPES_H) && \
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!defined(UINT64_MAX) && !defined(uint64_t)
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#error cannot find uint64_t type
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#endif
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#ifdef __cplusplus
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extern "C"
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{
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#endif
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/* Status code returned by most API routines. */
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enum ld_plugin_status
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{
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LDPS_OK = 0,
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LDPS_NO_SYMS, /* Attempt to get symbols that haven't been added. */
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LDPS_BAD_HANDLE, /* No claimed object associated with given handle. */
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LDPS_ERR
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/* Additional Error codes TBD. */
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};
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/* The version of the API specification. */
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enum ld_plugin_api_version
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{
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LD_PLUGIN_API_VERSION = 1
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};
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/* The type of output file being generated by the linker. */
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enum ld_plugin_output_file_type
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{
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LDPO_REL,
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LDPO_EXEC,
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LDPO_DYN,
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LDPO_PIE
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};
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/* An input file managed by the plugin library. */
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struct ld_plugin_input_file
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{
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const char *name;
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int fd;
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off_t offset;
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off_t filesize;
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void *handle;
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};
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/* A symbol belonging to an input file managed by the plugin library. */
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struct ld_plugin_symbol
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{
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char *name;
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char *version;
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int def;
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int visibility;
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uint64_t size;
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char *comdat_key;
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int resolution;
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};
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/* An object's section. */
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struct ld_plugin_section
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{
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const void* handle;
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unsigned int shndx;
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};
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/* Whether the symbol is a definition, reference, or common, weak or not. */
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enum ld_plugin_symbol_kind
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{
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LDPK_DEF,
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LDPK_WEAKDEF,
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LDPK_UNDEF,
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LDPK_WEAKUNDEF,
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LDPK_COMMON
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};
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/* The visibility of the symbol. */
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enum ld_plugin_symbol_visibility
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{
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LDPV_DEFAULT,
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LDPV_PROTECTED,
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LDPV_INTERNAL,
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LDPV_HIDDEN
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};
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/* How a symbol is resolved. */
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enum ld_plugin_symbol_resolution
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{
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LDPR_UNKNOWN = 0,
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/* Symbol is still undefined at this point. */
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LDPR_UNDEF,
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/* This is the prevailing definition of the symbol, with references from
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regular object code. */
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LDPR_PREVAILING_DEF,
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/* This is the prevailing definition of the symbol, with no
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references from regular objects. It is only referenced from IR
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code. */
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LDPR_PREVAILING_DEF_IRONLY,
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/* This definition was pre-empted by a definition in a regular
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object file. */
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LDPR_PREEMPTED_REG,
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/* This definition was pre-empted by a definition in another IR file. */
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LDPR_PREEMPTED_IR,
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/* This symbol was resolved by a definition in another IR file. */
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LDPR_RESOLVED_IR,
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/* This symbol was resolved by a definition in a regular object
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linked into the main executable. */
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LDPR_RESOLVED_EXEC,
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/* This symbol was resolved by a definition in a shared object. */
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LDPR_RESOLVED_DYN,
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/* This is the prevailing definition of the symbol, with no
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references from regular objects. It is only referenced from IR
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code, but the symbol is exported and may be referenced from
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a dynamic object (not seen at link time). */
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LDPR_PREVAILING_DEF_IRONLY_EXP
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};
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/* The plugin library's "claim file" handler. */
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typedef
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enum ld_plugin_status
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(*ld_plugin_claim_file_handler) (
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const struct ld_plugin_input_file *file, int *claimed);
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/* The plugin library's "all symbols read" handler. */
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typedef
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enum ld_plugin_status
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(*ld_plugin_all_symbols_read_handler) (void);
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/* The plugin library's cleanup handler. */
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typedef
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enum ld_plugin_status
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(*ld_plugin_cleanup_handler) (void);
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/* The linker's interface for registering the "claim file" handler. */
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typedef
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enum ld_plugin_status
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(*ld_plugin_register_claim_file) (ld_plugin_claim_file_handler handler);
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/* The linker's interface for registering the "all symbols read" handler. */
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typedef
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enum ld_plugin_status
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(*ld_plugin_register_all_symbols_read) (
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ld_plugin_all_symbols_read_handler handler);
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/* The linker's interface for registering the cleanup handler. */
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typedef
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enum ld_plugin_status
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(*ld_plugin_register_cleanup) (ld_plugin_cleanup_handler handler);
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/* The linker's interface for adding symbols from a claimed input file. */
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typedef
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enum ld_plugin_status
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(*ld_plugin_add_symbols) (void *handle, int nsyms,
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const struct ld_plugin_symbol *syms);
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/* The linker's interface for getting the input file information with
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an open (possibly re-opened) file descriptor. */
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typedef
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enum ld_plugin_status
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(*ld_plugin_get_input_file) (const void *handle,
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struct ld_plugin_input_file *file);
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typedef
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enum ld_plugin_status
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(*ld_plugin_get_view) (const void *handle, const void **viewp);
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/* The linker's interface for releasing the input file. */
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typedef
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enum ld_plugin_status
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(*ld_plugin_release_input_file) (const void *handle);
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/* The linker's interface for retrieving symbol resolution information. */
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typedef
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enum ld_plugin_status
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(*ld_plugin_get_symbols) (const void *handle, int nsyms,
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struct ld_plugin_symbol *syms);
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/* The linker's interface for adding a compiled input file. */
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typedef
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enum ld_plugin_status
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(*ld_plugin_add_input_file) (const char *pathname);
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/* The linker's interface for adding a library that should be searched. */
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typedef
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enum ld_plugin_status
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(*ld_plugin_add_input_library) (const char *libname);
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/* The linker's interface for adding a library path that should be searched. */
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typedef
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enum ld_plugin_status
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(*ld_plugin_set_extra_library_path) (const char *path);
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/* The linker's interface for issuing a warning or error message. */
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typedef
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enum ld_plugin_status
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(*ld_plugin_message) (int level, const char *format, ...);
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/* The linker's interface for retrieving the number of sections in an object.
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The handle is obtained in the claim_file handler. This interface should
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only be invoked in the claim_file handler. This function sets *COUNT to
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the number of sections in the object. */
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typedef
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enum ld_plugin_status
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(*ld_plugin_get_input_section_count) (const void* handle, unsigned int *count);
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/* The linker's interface for retrieving the section type of a specific
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section in an object. This interface should only be invoked in the
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claim_file handler. This function sets *TYPE to an ELF SHT_xxx value. */
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typedef
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enum ld_plugin_status
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(*ld_plugin_get_input_section_type) (const struct ld_plugin_section section,
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unsigned int *type);
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/* The linker's interface for retrieving the name of a specific section in
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an object. This interface should only be invoked in the claim_file handler.
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This function sets *SECTION_NAME_PTR to a null-terminated buffer allocated
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by malloc. The plugin must free *SECTION_NAME_PTR. */
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typedef
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enum ld_plugin_status
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(*ld_plugin_get_input_section_name) (const struct ld_plugin_section section,
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char **section_name_ptr);
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/* The linker's interface for retrieving the contents of a specific section
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in an object. This interface should only be invoked in the claim_file
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handler. This function sets *SECTION_CONTENTS to point to a buffer that is
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valid until clam_file handler returns. It sets *LEN to the size of the
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buffer. */
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typedef
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enum ld_plugin_status
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(*ld_plugin_get_input_section_contents) (const struct ld_plugin_section section,
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const unsigned char **section_contents,
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size_t* len);
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/* The linker's interface for specifying the desired order of sections.
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The sections should be specifed using the array SECTION_LIST in the
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order in which they should appear in the final layout. NUM_SECTIONS
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specifies the number of entries in each array. This should be invoked
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in the all_symbols_read handler. */
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typedef
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enum ld_plugin_status
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(*ld_plugin_update_section_order) (const struct ld_plugin_section *section_list,
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unsigned int num_sections);
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/* The linker's interface for specifying that reordering of sections is
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desired so that the linker can prepare for it. This should be invoked
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before update_section_order, preferably in the claim_file handler. */
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typedef
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enum ld_plugin_status
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(*ld_plugin_allow_section_ordering) (void);
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/* The linker's interface for specifying that a subset of sections is
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to be mapped to a unique segment. If the plugin wants to call
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unique_segment_for_sections, it must call this function from a
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claim_file_handler or when it is first loaded. */
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typedef
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enum ld_plugin_status
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(*ld_plugin_allow_unique_segment_for_sections) (void);
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/* The linker's interface for specifying that a specific set of sections
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must be mapped to a unique segment. ELF segments do not have names
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and the NAME is used as the name of the newly created output section
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that is then placed in the unique PT_LOAD segment. FLAGS is used to
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specify if any additional segment flags need to be set. For instance,
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a specific segment flag can be set to identify this segment. Unsetting
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segment flags that would be set by default is not possible. The
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parameter SEGMENT_ALIGNMENT when non-zero will override the default. */
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typedef
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enum ld_plugin_status
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(*ld_plugin_unique_segment_for_sections) (
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const char* segment_name,
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uint64_t segment_flags,
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uint64_t segment_alignment,
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const struct ld_plugin_section * section_list,
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unsigned int num_sections);
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/* The linker's interface for retrieving the section alignment requirement
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of a specific section in an object. This interface should only be invoked in the
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claim_file handler. This function sets *ADDRALIGN to the ELF sh_addralign
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value of the input section. */
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typedef
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enum ld_plugin_status
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(*ld_plugin_get_input_section_alignment) (const struct ld_plugin_section section,
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unsigned int *addralign);
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/* The linker's interface for retrieving the section size of a specific section
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in an object. This interface should only be invoked in the claim_file handler.
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This function sets *SECSIZE to the ELF sh_size
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value of the input section. */
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typedef
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enum ld_plugin_status
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(*ld_plugin_get_input_section_size) (const struct ld_plugin_section section,
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uint64_t *secsize);
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typedef
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enum ld_plugin_status
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(*ld_plugin_new_input_handler) (const struct ld_plugin_input_file *file);
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/* The linker's interface for registering the "new_input" handler. This handler
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will be notified when a new input file has been added after the
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all_symbols_read event, allowing the plugin to, for example, set a unique
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segment for sections in plugin-generated input files. */
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typedef
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enum ld_plugin_status
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(*ld_plugin_register_new_input) (ld_plugin_new_input_handler handler);
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/* The linker's interface for getting the list of wrapped symbols using the
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--wrap option. This sets *NUM_SYMBOLS to number of wrapped symbols and
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*WRAP_SYMBOL_LIST to the list of wrapped symbols. */
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typedef
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enum ld_plugin_status
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(*ld_plugin_get_wrap_symbols) (uint64_t *num_symbols,
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const char ***wrap_symbol_list);
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enum ld_plugin_level
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{
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LDPL_INFO,
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LDPL_WARNING,
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LDPL_ERROR,
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LDPL_FATAL
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};
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/* Values for the tv_tag field of the transfer vector. */
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enum ld_plugin_tag
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{
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LDPT_NULL = 0,
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LDPT_API_VERSION = 1,
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LDPT_GOLD_VERSION = 2,
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LDPT_LINKER_OUTPUT = 3,
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LDPT_OPTION = 4,
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LDPT_REGISTER_CLAIM_FILE_HOOK = 5,
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LDPT_REGISTER_ALL_SYMBOLS_READ_HOOK = 6,
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LDPT_REGISTER_CLEANUP_HOOK = 7,
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LDPT_ADD_SYMBOLS = 8,
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LDPT_GET_SYMBOLS = 9,
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LDPT_ADD_INPUT_FILE = 10,
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LDPT_MESSAGE = 11,
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LDPT_GET_INPUT_FILE = 12,
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LDPT_RELEASE_INPUT_FILE = 13,
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LDPT_ADD_INPUT_LIBRARY = 14,
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LDPT_OUTPUT_NAME = 15,
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LDPT_SET_EXTRA_LIBRARY_PATH = 16,
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LDPT_GNU_LD_VERSION = 17,
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LDPT_GET_VIEW = 18,
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LDPT_GET_INPUT_SECTION_COUNT = 19,
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LDPT_GET_INPUT_SECTION_TYPE = 20,
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LDPT_GET_INPUT_SECTION_NAME = 21,
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LDPT_GET_INPUT_SECTION_CONTENTS = 22,
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LDPT_UPDATE_SECTION_ORDER = 23,
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LDPT_ALLOW_SECTION_ORDERING = 24,
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LDPT_GET_SYMBOLS_V2 = 25,
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LDPT_ALLOW_UNIQUE_SEGMENT_FOR_SECTIONS = 26,
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LDPT_UNIQUE_SEGMENT_FOR_SECTIONS = 27,
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LDPT_GET_SYMBOLS_V3 = 28,
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LDPT_GET_INPUT_SECTION_ALIGNMENT = 29,
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LDPT_GET_INPUT_SECTION_SIZE = 30,
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LDPT_REGISTER_NEW_INPUT_HOOK = 31,
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LDPT_GET_WRAP_SYMBOLS = 32
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};
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/* The plugin transfer vector. */
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struct ld_plugin_tv
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{
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enum ld_plugin_tag tv_tag;
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union
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{
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int tv_val;
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const char *tv_string;
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ld_plugin_register_claim_file tv_register_claim_file;
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ld_plugin_register_all_symbols_read tv_register_all_symbols_read;
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ld_plugin_register_cleanup tv_register_cleanup;
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ld_plugin_add_symbols tv_add_symbols;
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ld_plugin_get_symbols tv_get_symbols;
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ld_plugin_add_input_file tv_add_input_file;
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ld_plugin_message tv_message;
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ld_plugin_get_input_file tv_get_input_file;
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ld_plugin_get_view tv_get_view;
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ld_plugin_release_input_file tv_release_input_file;
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ld_plugin_add_input_library tv_add_input_library;
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ld_plugin_set_extra_library_path tv_set_extra_library_path;
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ld_plugin_get_input_section_count tv_get_input_section_count;
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ld_plugin_get_input_section_type tv_get_input_section_type;
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ld_plugin_get_input_section_name tv_get_input_section_name;
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ld_plugin_get_input_section_contents tv_get_input_section_contents;
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ld_plugin_update_section_order tv_update_section_order;
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ld_plugin_allow_section_ordering tv_allow_section_ordering;
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ld_plugin_allow_unique_segment_for_sections tv_allow_unique_segment_for_sections;
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ld_plugin_unique_segment_for_sections tv_unique_segment_for_sections;
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ld_plugin_get_input_section_alignment tv_get_input_section_alignment;
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ld_plugin_get_input_section_size tv_get_input_section_size;
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ld_plugin_register_new_input tv_register_new_input;
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ld_plugin_get_wrap_symbols tv_get_wrap_symbols;
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} tv_u;
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};
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/* The plugin library's "onload" entry point. */
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typedef
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enum ld_plugin_status
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(*ld_plugin_onload) (struct ld_plugin_tv *tv);
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#ifdef __cplusplus
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}
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#endif
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#endif /* !defined(PLUGIN_API_H) */
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