Files
binutils-gdb/libctf/ctf-impl.h
Nick Alcock 72c83edd92 libctf: add the ctf_link machinery
This is the start of work on the core of the linking mechanism for CTF
sections.  This commit handles the type and string sections.

The linker calls these functions in sequence:

ctf_link_add_ctf: to add each CTF section in the input in turn to a
  newly-created ctf_file_t (which will appear in the output, and which
  itself will become the shared parent that contains types that all
  TUs have in common (in all link modes) and all types that do not
  have conflicting definitions between types (by default).  Input files
  that are themselves products of ld -r are supported, though this is
  not heavily tested yet.

ctf_link: called once all input files are added to merge the types in
  all the input containers into the output container, eliminating
  duplicates.

ctf_link_add_strtab: called once the ELF string table is finalized and
  all its offsets are known, this calls a callback provided by the
  linker which returns the string content and offset of every string in
  the ELF strtab in turn: all these strings which appear in the input
  CTF strtab are eliminated from it in favour of the ELF strtab:
  equally, any strings that only appear in the input strtab will
  reappear in the internal CTF strtab of the output.

ctf_link_shuffle_syms (not yet implemented): called once the ELF symtab
  is finalized, this calls a callback provided by the linker which
  returns information on every symbol in turn as a ctf_link_sym_t.  This
  is then used to shuffle the function info and data object sections in
  the CTF section into symbol table order, eliminating the index
  sections which map those sections to symbol names before that point.
  Currently just returns ECTF_NOTYET.

ctf_link_write: Returns a buffer containing either a serialized
  ctf_file_t (if there are no types with conflicting definitions in the
  object files in the link) or a ctf_archive_t containing a large
  ctf_file_t (the common types) and a bunch of small ones named after
  individual CUs in which conflicting types are found (containing the
  conflicting types, and all types that reference them).  A threshold
  size above which compression takes place is passed as one parameter.
  (Currently, only gzip compression is supported, but I hope to add lzma
  as well.)

Lifetime rules for this are simple: don't close the input CTF files
until you've called ctf_link for the last time.  We do not assume
that symbols or strings passed in by the callback outlast the
call to ctf_link_add_strtab or ctf_link_shuffle_syms.

Right now, the duplicate elimination mechanism is the one already
present as part of the ctf_add_type function, and is not particularly
good: it misses numerous actual duplicates, and the conflicting-types
detection hardly ever reports that types conflict, even when they do
(one of them just tends to get silently dropped): it is also very slow.
This will all be fixed in the next few weeks, but the fix hardly touches
any of this code, and the linker does work without it, just not as
well as it otherwise might.  (And when no CTF section is present,
there is no effect on performance, of course.  So only people using
a trunk GCC with not-yet-committed patches will even notice.  By the
time it gets upstream, things should be better.)

v3: Fix error handling.
v4: check for strdup failure.
v5: fix tabdamage.

include/
	* ctf-api.h (struct ctf_link_sym): New, a symbol in flight to the
	libctf linking machinery.
	(CTF_LINK_SHARE_UNCONFLICTED): New.
	(CTF_LINK_SHARE_DUPLICATED): New.
	(ECTF_LINKADDEDLATE): New, replacing ECTF_UNUSED.
	(ECTF_NOTYET): New, a 'not yet implemented' message.
	(ctf_link_add_ctf): New, add an input file's CTF to the link.
	(ctf_link): New, merge the type and string sections.
	(ctf_link_strtab_string_f): New, callback for feeding strtab info.
	(ctf_link_iter_symbol_f): New, callback for feeding symtab info.
	(ctf_link_add_strtab): New, tell the CTF linker about the ELF
	strtab's strings.
	(ctf_link_shuffle_syms): New, ask the CTF linker to shuffle its
	symbols into symtab order.
	(ctf_link_write): New, ask the CTF linker to write the CTF out.

libctf/
	* ctf-link.c: New file, linking of the string and type sections.
	* Makefile.am (libctf_a_SOURCES): Add it.
	* Makefile.in: Regenerate.

	* ctf-impl.h (ctf_file_t): New fields ctf_link_inputs,
	ctf_link_outputs.
	* ctf-create.c (ctf_update): Update accordingly.
	* ctf-open.c (ctf_file_close): Likewise.
	* ctf-error.c (_ctf_errlist): Updated with new errors.
2019-10-03 17:04:55 +01:00

447 lines
18 KiB
C

/* Implementation header.
Copyright (C) 2019 Free Software Foundation, Inc.
This file is part of libctf.
libctf is free software; you can redistribute it and/or modify it under
the terms of the GNU General Public License as published by the Free
Software Foundation; either version 3, or (at your option) any later
version.
This program is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
See the GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; see the file COPYING. If not see
<http://www.gnu.org/licenses/>. */
#ifndef _CTF_IMPL_H
#define _CTF_IMPL_H
#include "config.h"
#include <errno.h>
#include "ctf-decls.h"
#include <ctf-api.h>
#include <sys/types.h>
#include <stdlib.h>
#include <stdarg.h>
#include <stdio.h>
#include <stdint.h>
#include <limits.h>
#include <ctype.h>
#include <elf.h>
#include <bfd.h>
#ifdef __cplusplus
extern "C"
{
#endif
/* Compiler attributes. */
#if defined (__GNUC__)
/* GCC. We assume that all compilers claiming to be GCC support sufficiently
many GCC attributes that the code below works. If some non-GCC compilers
masquerading as GCC in fact do not implement these attributes, version checks
may be required. */
/* We use the _libctf_*_ pattern to avoid clashes with any future attribute
macros glibc may introduce, which have names of the pattern
__attribute_blah__. */
#define _libctf_printflike_(string_index,first_to_check) \
__attribute__ ((__format__ (__printf__, (string_index), (first_to_check))))
#define _libctf_unlikely_(x) __builtin_expect ((x), 0)
#define _libctf_unused_ __attribute__ ((__unused__))
#define _libctf_malloc_ __attribute__((__malloc__))
#endif
/* libctf in-memory state. */
typedef struct ctf_fixed_hash ctf_hash_t; /* Private to ctf-hash.c. */
typedef struct ctf_dynhash ctf_dynhash_t; /* Private to ctf-hash.c. */
typedef struct ctf_strs
{
const char *cts_strs; /* Base address of string table. */
size_t cts_len; /* Size of string table in bytes. */
} ctf_strs_t;
typedef struct ctf_strs_writable
{
char *cts_strs; /* Base address of string table. */
size_t cts_len; /* Size of string table in bytes. */
} ctf_strs_writable_t;
typedef struct ctf_dmodel
{
const char *ctd_name; /* Data model name. */
int ctd_code; /* Data model code. */
size_t ctd_pointer; /* Size of void * in bytes. */
size_t ctd_char; /* Size of char in bytes. */
size_t ctd_short; /* Size of short in bytes. */
size_t ctd_int; /* Size of int in bytes. */
size_t ctd_long; /* Size of long in bytes. */
} ctf_dmodel_t;
typedef struct ctf_lookup
{
const char *ctl_prefix; /* String prefix for this lookup. */
size_t ctl_len; /* Length of prefix string in bytes. */
ctf_hash_t *ctl_hash; /* Pointer to hash table for lookup. */
} ctf_lookup_t;
typedef struct ctf_fileops
{
uint32_t (*ctfo_get_kind) (uint32_t);
uint32_t (*ctfo_get_root) (uint32_t);
uint32_t (*ctfo_get_vlen) (uint32_t);
ssize_t (*ctfo_get_ctt_size) (const ctf_file_t *, const ctf_type_t *,
ssize_t *, ssize_t *);
ssize_t (*ctfo_get_vbytes) (unsigned short, ssize_t, size_t);
} ctf_fileops_t;
typedef struct ctf_list
{
struct ctf_list *l_prev; /* Previous pointer or tail pointer. */
struct ctf_list *l_next; /* Next pointer or head pointer. */
} ctf_list_t;
typedef enum
{
CTF_PREC_BASE,
CTF_PREC_POINTER,
CTF_PREC_ARRAY,
CTF_PREC_FUNCTION,
CTF_PREC_MAX
} ctf_decl_prec_t;
typedef struct ctf_decl_node
{
ctf_list_t cd_list; /* Linked list pointers. */
ctf_id_t cd_type; /* Type identifier. */
uint32_t cd_kind; /* Type kind. */
uint32_t cd_n; /* Type dimension if array. */
} ctf_decl_node_t;
typedef struct ctf_decl
{
ctf_list_t cd_nodes[CTF_PREC_MAX]; /* Declaration node stacks. */
int cd_order[CTF_PREC_MAX]; /* Storage order of decls. */
ctf_decl_prec_t cd_qualp; /* Qualifier precision. */
ctf_decl_prec_t cd_ordp; /* Ordered precision. */
char *cd_buf; /* Buffer for output. */
int cd_err; /* Saved error value. */
int cd_enomem; /* Nonzero if OOM during printing. */
} ctf_decl_t;
typedef struct ctf_dmdef
{
ctf_list_t dmd_list; /* List forward/back pointers. */
char *dmd_name; /* Name of this member. */
ctf_id_t dmd_type; /* Type of this member (for sou). */
unsigned long dmd_offset; /* Offset of this member in bits (for sou). */
int dmd_value; /* Value of this member (for enum). */
} ctf_dmdef_t;
typedef struct ctf_dtdef
{
ctf_list_t dtd_list; /* List forward/back pointers. */
char *dtd_name; /* Name associated with definition (if any). */
ctf_id_t dtd_type; /* Type identifier for this definition. */
ctf_type_t dtd_data; /* Type node: name left unpopulated. */
union
{
ctf_list_t dtu_members; /* struct, union, or enum */
ctf_arinfo_t dtu_arr; /* array */
ctf_encoding_t dtu_enc; /* integer or float */
ctf_id_t *dtu_argv; /* function */
ctf_slice_t dtu_slice; /* slice */
} dtd_u;
} ctf_dtdef_t;
typedef struct ctf_dvdef
{
ctf_list_t dvd_list; /* List forward/back pointers. */
char *dvd_name; /* Name associated with variable. */
ctf_id_t dvd_type; /* Type of variable. */
unsigned long dvd_snapshots; /* Snapshot count when inserted. */
} ctf_dvdef_t;
typedef struct ctf_bundle
{
ctf_file_t *ctb_file; /* CTF container handle. */
ctf_id_t ctb_type; /* CTF type identifier. */
ctf_dtdef_t *ctb_dtd; /* CTF dynamic type definition (if any). */
} ctf_bundle_t;
/* Atoms associate strings with a list of the CTF items that reference that
string, so that ctf_update() can instantiate all the strings using the
ctf_str_atoms and then reassociate them with the real string later.
Strings can be interned into ctf_str_atom without having refs associated
with them, for values that are returned to callers, etc. Items are only
removed from this table on ctf_close(), but on every ctf_update(), all the
csa_refs in all entries are purged. */
typedef struct ctf_str_atom
{
const char *csa_str; /* Backpointer to string (hash key). */
ctf_list_t csa_refs; /* This string's refs. */
uint32_t csa_offset; /* External strtab offset, if any. */
unsigned long csa_snapshot_id; /* Snapshot ID at time of creation. */
} ctf_str_atom_t;
/* The refs of a single string in the atoms table. */
typedef struct ctf_str_atom_ref
{
ctf_list_t caf_list; /* List forward/back pointers. */
uint32_t *caf_ref; /* A single ref to this string. */
} ctf_str_atom_ref_t;
/* The ctf_file is the structure used to represent a CTF container to library
clients, who see it only as an opaque pointer. Modifications can therefore
be made freely to this structure without regard to client versioning. The
ctf_file_t typedef appears in <ctf-api.h> and declares a forward tag.
NOTE: ctf_update() requires that everything inside of ctf_file either be an
immediate value, a pointer to dynamically allocated data *outside* of the
ctf_file itself, or a pointer to statically allocated data. If you add a
pointer to ctf_file that points to something within the ctf_file itself,
you must make corresponding changes to ctf_update(). */
struct ctf_file
{
const ctf_fileops_t *ctf_fileops; /* Version-specific file operations. */
struct ctf_header *ctf_header; /* The header from this CTF file. */
unsigned char ctf_openflags; /* Flags the file had when opened. */
ctf_sect_t ctf_data; /* CTF data from object file. */
ctf_sect_t ctf_symtab; /* Symbol table from object file. */
ctf_sect_t ctf_strtab; /* String table from object file. */
ctf_dynhash_t *ctf_syn_ext_strtab; /* Maps ext-strtab offsets to names. */
void *ctf_data_mmapped; /* CTF data we mmapped, to free later. */
size_t ctf_data_mmapped_len; /* Length of CTF data we mmapped. */
ctf_hash_t *ctf_structs; /* Hash table of struct types. */
ctf_hash_t *ctf_unions; /* Hash table of union types. */
ctf_hash_t *ctf_enums; /* Hash table of enum types. */
ctf_hash_t *ctf_names; /* Hash table of remaining type names. */
ctf_lookup_t ctf_lookups[5]; /* Pointers to hashes for name lookup. */
ctf_strs_t ctf_str[2]; /* Array of string table base and bounds. */
ctf_dynhash_t *ctf_str_atoms; /* Hash table of ctf_str_atoms_t. */
uint64_t ctf_str_num_refs; /* Number of refs to cts_str_atoms. */
unsigned char *ctf_base; /* CTF file pointer. */
unsigned char *ctf_dynbase; /* Freeable CTF file pointer. */
unsigned char *ctf_buf; /* Uncompressed CTF data buffer. */
size_t ctf_size; /* Size of CTF header + uncompressed data. */
uint32_t *ctf_sxlate; /* Translation table for symtab entries. */
unsigned long ctf_nsyms; /* Number of entries in symtab xlate table. */
uint32_t *ctf_txlate; /* Translation table for type IDs. */
uint32_t *ctf_ptrtab; /* Translation table for pointer-to lookups. */
struct ctf_varent *ctf_vars; /* Sorted variable->type mapping. */
unsigned long ctf_nvars; /* Number of variables in ctf_vars. */
unsigned long ctf_typemax; /* Maximum valid type ID number. */
const ctf_dmodel_t *ctf_dmodel; /* Data model pointer (see above). */
const char *ctf_cuname; /* Compilation unit name (if any). */
char *ctf_dyncuname; /* Dynamically allocated name of CU. */
struct ctf_file *ctf_parent; /* Parent CTF container (if any). */
const char *ctf_parlabel; /* Label in parent container (if any). */
const char *ctf_parname; /* Basename of parent (if any). */
char *ctf_dynparname; /* Dynamically allocated name of parent. */
uint32_t ctf_parmax; /* Highest type ID of a parent type. */
uint32_t ctf_refcnt; /* Reference count (for parent links). */
uint32_t ctf_flags; /* Libctf flags (see below). */
int ctf_errno; /* Error code for most recent error. */
int ctf_version; /* CTF data version. */
ctf_dynhash_t *ctf_dthash; /* Hash of dynamic type definitions. */
ctf_dynhash_t *ctf_dtbyname; /* DTDs, indexed by name. */
ctf_list_t ctf_dtdefs; /* List of dynamic type definitions. */
ctf_dynhash_t *ctf_dvhash; /* Hash of dynamic variable mappings. */
ctf_list_t ctf_dvdefs; /* List of dynamic variable definitions. */
unsigned long ctf_dtnextid; /* Next dynamic type id to assign. */
unsigned long ctf_dtoldid; /* Oldest id that has been committed. */
unsigned long ctf_snapshots; /* ctf_snapshot() plus ctf_update() count. */
unsigned long ctf_snapshot_lu; /* ctf_snapshot() call count at last update. */
ctf_archive_t *ctf_archive; /* Archive this ctf_file_t came from. */
ctf_dynhash_t *ctf_link_inputs; /* Inputs to this link. */
ctf_dynhash_t *ctf_link_outputs; /* Additional outputs from this link. */
char *ctf_tmp_typeslice; /* Storage for slicing up type names. */
size_t ctf_tmp_typeslicelen; /* Size of the typeslice. */
void *ctf_specific; /* Data for ctf_get/setspecific(). */
};
/* An abstraction over both a ctf_file_t and a ctf_archive_t. */
struct ctf_archive_internal
{
int ctfi_is_archive;
ctf_file_t *ctfi_file;
struct ctf_archive *ctfi_archive;
ctf_sect_t ctfi_symsect;
ctf_sect_t ctfi_strsect;
void *ctfi_data;
bfd *ctfi_abfd; /* Optional source of section data. */
void (*ctfi_bfd_close) (struct ctf_archive_internal *);
};
/* Return x rounded up to an alignment boundary.
eg, P2ROUNDUP(0x1234, 0x100) == 0x1300 (0x13*align)
eg, P2ROUNDUP(0x5600, 0x100) == 0x5600 (0x56*align) */
#define P2ROUNDUP(x, align) (-(-(x) & -(align)))
/* * If an offs is not aligned already then round it up and align it. */
#define LCTF_ALIGN_OFFS(offs, align) ((offs + (align - 1)) & ~(align - 1))
#define LCTF_TYPE_ISPARENT(fp, id) ((id) <= fp->ctf_parmax)
#define LCTF_TYPE_ISCHILD(fp, id) ((id) > fp->ctf_parmax)
#define LCTF_TYPE_TO_INDEX(fp, id) ((id) & (fp->ctf_parmax))
#define LCTF_INDEX_TO_TYPE(fp, id, child) (child ? ((id) | (fp->ctf_parmax+1)) : \
(id))
#define LCTF_INDEX_TO_TYPEPTR(fp, i) \
((ctf_type_t *)((uintptr_t)(fp)->ctf_buf + (fp)->ctf_txlate[(i)]))
#define LCTF_INFO_KIND(fp, info) ((fp)->ctf_fileops->ctfo_get_kind(info))
#define LCTF_INFO_ISROOT(fp, info) ((fp)->ctf_fileops->ctfo_get_root(info))
#define LCTF_INFO_VLEN(fp, info) ((fp)->ctf_fileops->ctfo_get_vlen(info))
#define LCTF_VBYTES(fp, kind, size, vlen) \
((fp)->ctf_fileops->ctfo_get_vbytes(kind, size, vlen))
static inline ssize_t ctf_get_ctt_size (const ctf_file_t *fp,
const ctf_type_t *tp,
ssize_t *sizep,
ssize_t *incrementp)
{
return (fp->ctf_fileops->ctfo_get_ctt_size (fp, tp, sizep, incrementp));
}
#define LCTF_CHILD 0x0001 /* CTF container is a child */
#define LCTF_RDWR 0x0002 /* CTF container is writable */
#define LCTF_DIRTY 0x0004 /* CTF container has been modified */
extern const ctf_type_t *ctf_lookup_by_id (ctf_file_t **, ctf_id_t);
typedef unsigned int (*ctf_hash_fun) (const void *ptr);
extern unsigned int ctf_hash_integer (const void *ptr);
extern unsigned int ctf_hash_string (const void *ptr);
typedef int (*ctf_hash_eq_fun) (const void *, const void *);
extern int ctf_hash_eq_integer (const void *, const void *);
extern int ctf_hash_eq_string (const void *, const void *);
typedef void (*ctf_hash_free_fun) (void *);
typedef void (*ctf_hash_iter_f) (void *key, void *value, void *arg);
typedef int (*ctf_hash_iter_remove_f) (void *key, void *value, void *arg);
extern ctf_hash_t *ctf_hash_create (unsigned long, ctf_hash_fun, ctf_hash_eq_fun);
extern int ctf_hash_insert_type (ctf_hash_t *, ctf_file_t *, uint32_t, uint32_t);
extern int ctf_hash_define_type (ctf_hash_t *, ctf_file_t *, uint32_t, uint32_t);
extern ctf_id_t ctf_hash_lookup_type (ctf_hash_t *, ctf_file_t *, const char *);
extern uint32_t ctf_hash_size (const ctf_hash_t *);
extern void ctf_hash_destroy (ctf_hash_t *);
extern ctf_dynhash_t *ctf_dynhash_create (ctf_hash_fun, ctf_hash_eq_fun,
ctf_hash_free_fun, ctf_hash_free_fun);
extern int ctf_dynhash_insert (ctf_dynhash_t *, void *, void *);
extern void ctf_dynhash_remove (ctf_dynhash_t *, const void *);
extern void *ctf_dynhash_lookup (ctf_dynhash_t *, const void *);
extern void ctf_dynhash_destroy (ctf_dynhash_t *);
extern void ctf_dynhash_iter (ctf_dynhash_t *, ctf_hash_iter_f, void *);
extern void ctf_dynhash_iter_remove (ctf_dynhash_t *, ctf_hash_iter_remove_f,
void *);
#define ctf_list_prev(elem) ((void *)(((ctf_list_t *)(elem))->l_prev))
#define ctf_list_next(elem) ((void *)(((ctf_list_t *)(elem))->l_next))
extern void ctf_list_append (ctf_list_t *, void *);
extern void ctf_list_prepend (ctf_list_t *, void *);
extern void ctf_list_delete (ctf_list_t *, void *);
extern int ctf_dtd_insert (ctf_file_t *, ctf_dtdef_t *);
extern void ctf_dtd_delete (ctf_file_t *, ctf_dtdef_t *);
extern ctf_dtdef_t *ctf_dtd_lookup (const ctf_file_t *, ctf_id_t);
extern ctf_dtdef_t *ctf_dynamic_type (const ctf_file_t *, ctf_id_t);
extern int ctf_dvd_insert (ctf_file_t *, ctf_dvdef_t *);
extern void ctf_dvd_delete (ctf_file_t *, ctf_dvdef_t *);
extern ctf_dvdef_t *ctf_dvd_lookup (const ctf_file_t *, const char *);
extern void ctf_decl_init (ctf_decl_t *);
extern void ctf_decl_fini (ctf_decl_t *);
extern void ctf_decl_push (ctf_decl_t *, ctf_file_t *, ctf_id_t);
_libctf_printflike_ (2, 3)
extern void ctf_decl_sprintf (ctf_decl_t *, const char *, ...);
extern char *ctf_decl_buf (ctf_decl_t *cd);
extern const char *ctf_strptr (ctf_file_t *, uint32_t);
extern const char *ctf_strraw (ctf_file_t *, uint32_t);
extern const char *ctf_strraw_explicit (ctf_file_t *, uint32_t,
ctf_strs_t *);
extern int ctf_str_create_atoms (ctf_file_t *);
extern void ctf_str_free_atoms (ctf_file_t *);
extern const char *ctf_str_add (ctf_file_t *, const char *);
extern const char *ctf_str_add_ref (ctf_file_t *, const char *, uint32_t *ref);
extern const char *ctf_str_add_external (ctf_file_t *, const char *, uint32_t offset);
extern void ctf_str_rollback (ctf_file_t *, ctf_snapshot_id_t);
extern void ctf_str_purge_refs (ctf_file_t *);
extern ctf_strs_writable_t ctf_str_write_strtab (ctf_file_t *);
extern struct ctf_archive *ctf_arc_open_internal (const char *, int *);
extern struct ctf_archive *ctf_arc_bufopen (const void *, size_t, int *);
extern void ctf_arc_close_internal (struct ctf_archive *);
extern void *ctf_set_open_errno (int *, int);
extern unsigned long ctf_set_errno (ctf_file_t *, int);
extern ctf_file_t *ctf_simple_open_internal (const char *, size_t, const char *,
size_t, size_t,
const char *, size_t,
ctf_dynhash_t *, int *);
extern ctf_file_t *ctf_bufopen_internal (const ctf_sect_t *, const ctf_sect_t *,
const ctf_sect_t *, ctf_dynhash_t *,
int *);
_libctf_malloc_
extern void *ctf_mmap (size_t length, size_t offset, int fd);
extern void ctf_munmap (void *, size_t);
extern ssize_t ctf_pread (int fd, void *buf, ssize_t count, off_t offset);
_libctf_malloc_
extern void *ctf_alloc (size_t);
extern void ctf_free (void *);
extern void *ctf_realloc (ctf_file_t *, void *, size_t);
_libctf_malloc_
extern char *ctf_strdup (const char *);
extern char *ctf_str_append (char *, const char *);
extern const char *ctf_strerror (int);
extern ctf_id_t ctf_type_resolve_unsliced (ctf_file_t *, ctf_id_t);
extern int ctf_type_kind_unsliced (ctf_file_t *, ctf_id_t);
_libctf_printflike_ (1, 2)
extern void ctf_dprintf (const char *, ...);
extern void libctf_init_debug (void);
extern Elf64_Sym *ctf_sym_to_elf64 (const Elf32_Sym *src, Elf64_Sym *dst);
extern const char *ctf_lookup_symbol_name (ctf_file_t *fp, unsigned long symidx);
/* Variables, all underscore-prepended. */
extern const char _CTF_SECTION[]; /* name of CTF ELF section */
extern const char _CTF_NULLSTR[]; /* empty string */
extern int _libctf_version; /* library client version */
extern int _libctf_debug; /* debugging messages enabled */
#ifdef __cplusplus
}
#endif
#endif /* _CTF_IMPL_H */