binutils-gdb/ld/ldmisc.c
Nick Alcock 1ff6de0312 bfd, ld: add CTF section linking
This is quite complicated because the CTF section's contents depend on
the final contents of the symtab and strtab, because it has two sections
whose contents are shuffled to be in 1:1 correspondence with the symtab,
and an internal strtab that gets deduplicated against the ELF strtab
(with offsets adjusted to point into the ELF strtab instead).  It is
also compressed if large enough, so its size depends on its contents!

So we cannot construct it as early as most sections: we cannot even
*begin* construction until after the symtab and strtab are finalized.
Thankfully there is already one section treated similarly: compressed
debugging sections: the only differences are that compressed debugging
sections have extra handling to deal with their changing name if
compressed (CTF sections are always called ".ctf" for now, though we
have reserved ".ctf.*" against future use), and that compressed
debugging sections have previously-uncompressed content which has to be
stashed away for later compression, while CTF sections have no content
at all until we generate it (very late).

BFD also cannot do the link itself: libctf knows how to do it, and BFD
cannot call libctf directly because libctf already depends on bfd for
file I/O.  So we have to use a pair of callbacks, one, examine_strtab,
which allows a caller to examine the symtab and strtab after
finalization (called from elf_link_swap_symbols_out(), right before the
symtabs are written, and after the strtab has been finalized), and one
which actually does the emission (called emit_ctf simply because it is
grouped with a bunch of section-specific late-emission function calls at
the bottom of bfd_elf_final_link, and a section-specific name seems best
for that).  emit_ctf is actually called *twice*: once from lang_process
if the emulation suggests that this bfd target does not examine the
symtab or strtab, and once via a bfd callback if it does.  (This means
that non-ELF targets still get CTF emitted, even though the late CTF
emission stage is never called for them).

v2: merged with non-ELF support patch: slight commit message
    adjustments.
v3: do not spend time merging CTF, or crash, if the CTF section is
    explicitly discarded.  Do not try to merge or compress CTF unless
    linking.
v4: add CTF_COMPRESSION_THRESHOLD.  Annul the freed input ctf_file_t's
    after writeout: set SEC_IN_MEMORY on the output contents so a future
    bfd enhancement knows it could free it.  Add SEC_LINKER_CREATED |
    SEC_KEEP to avoid having to add .ctf to the linker script.  Drop
    now-unnecessary ldlang.h-level elf-bfd.h include and hackery around
    it.  Adapt to elf32.em->elf.em and elf-generic.em->ldelf*.c
    changes.
v5: fix tabdamage.  Drop #inclusions in .h files: include in .c files,
    .em files, and use struct forwards instead.  Use bfd_section_is_ctf
    inline function rather than SECTION_IS_CTF macro.  Move a few
    comments.

	* Makefile.def (dependencies): all-ld depends on all-libctf.
	* Makefile.in: Regenerated.

include/
	* bfdlink.h (elf_strtab_hash): New forward.
	(elf_sym_strtab): Likewise.
	(struct bfd_link_callbacks <examine_strtab>): New.
	(struct bfd_link_callbacks <emit_ctf>): Likewise.

bfd/
	* elf-bfd.h (bfd_section_is_ctf): New inline function.
	* elf.c (special_sections_c): Add ".ctf".
	(assign_file_positions_for_non_load_sections): Note that
	compressed debugging sections etc are not assigned here.  Treat
	CTF sections like SEC_ELF_COMPRESS sections when is_linker_output:
	sh_offset -1.
	(assign_file_positions_except_relocs): Likewise.
	(find_section_in_list): Note that debugging and CTF sections, as
	well as reloc sections, are assigned later.
	(_bfd_elf_assign_file_positions_for_non_load): CTF sections get
	their size and contents updated.
	(_bfd_elf_set_section_contents): Skip CTF sections: unlike
	compressed sections, they have no uncompressed content to copy at
	this stage.
	* elflink.c (elf_link_swap_symbols_out): Call the examine_strtab
	callback right before the strtab is written out.
	(bfd_elf_final_link): Don't cache the section contents of CTF
	sections: they are not populated yet.  Call the emit_ctf callback
	right at the end, after all the symbols and strings are flushed
	out.

ld/
	* ldlang.h: (struct lang_input_statement_struct): Add the_ctf.
	(struct elf_sym_strtab): Add forward.
	(struct elf_strtab_hash): Likewise.
	(ldlang_ctf_apply_strsym): Declare.
	(ldlang_write_ctf_late): Likewise.
	* ldemul.h (ldemul_emit_ctf_early): New.
	(ldemul_examine_strtab_for_ctf): Likewise.
	(ld_emulation_xfer_type) <emit_ctf_early>: Likewise.
	(ld_emulation_xfer_type) <examine_strtab_for_ctf>: Likewise.
	* ldemul.c (ldemul_emit_ctf_early): New.
	(ldemul_examine_strtab_for_ctf): Likewise.
	* ldlang.c: Include ctf-api.h.
	(CTF_COMPRESSION_THRESHOLD): New.
	(ctf_output): New. Initialized in...
	(ldlang_open_ctf): ... this new function.  Open all the CTF
	sections in the input files: mark them non-loaded and empty
	so as not to copy their contents to the output, but linker-created
	so the section gets created in the target.
	(ldlang_merge_ctf): New, merge types via ctf_link_add_ctf and
	ctf_link.
	(ldlang_ctf_apply_strsym): New, an examine_strtab callback: wrap
	ldemul_examine_strtab_for_ctf.
	(lang_write_ctf): New, write out the CTF section.
	(ldlang_write_ctf_late): New, late call via bfd's emit_ctf hook.
	(lang_process): Call ldlang_open_ctf, ldlang_merge_ctf, and
	lang_write_ctf.
	* ldmain.c (link_callbacks): Add ldlang_ctf_apply_strsym,
	ldlang_write_ctf_late.
	* emultempl/aix.em: Add ctf-api.h.
	* emultempl/armcoff.em: Likewise.
	* emultempl/beos.em: Likewise.
	* emultempl/elf.em: Likewise.
	* emultempl/generic.em: Likewise.
	* emultempl/linux.em: Likewise.
	* emultempl/msp430.em: Likewise.
	* emultempl/pe.em: Likewise.
	* emultempl/pep.em: Likewise.
	* emultempl/ticoff.em: Likewise.
	* emultempl/vanilla.em: Likewise.
	* ldcref.c: Likewise.
	* ldctor.c: Likewise.
	* ldelf.c: Likewise.
	* ldelfgen.c: Likewise.
	* ldemul.c: Likewise.
	* ldexp.c: Likewise.
	* ldfile.c: Likewise.
	* ldgram.c: Likewise.
	* ldlex.l: Likewise.
	* ldmain.c: Likewise.
	* ldmisc.c: Likewise.
	* ldver.c: Likewise.
	* ldwrite.c: Likewise.
	* lexsup.c: Likewise.
	* mri.c: Likewise.
	* pe-dll.c: Likewise.
	* plugin.c: Likewise.

	* ldelfgen.c (ldelf_emit_ctf_early): New.
	(ldelf_examine_strtab_for_ctf): tell libctf about the symtab and
	strtab.
	(struct ctf_strsym_iter_cb_arg): New, state to do so.
	(ldelf_ctf_strtab_iter_cb): New: tell libctf about
	each string in the strtab in turn.
	(ldelf_ctf_symbols_iter_cb): New, tell libctf
	about each symbol in the symtab in turn.
	* ldelfgen.h (struct elf_sym_strtab): Add forward.
	(struct elf_strtab_hash): Likewise.
	(struct ctf_file): Likewise.
	(ldelf_emit_ctf_early): Declare.
	(ldelf_examine_strtab_for_ctf): Likewise.
	* emultempl/elf-generic.em (LDEMUL_EMIT_CTF_EARLY): Set it.
	(LDEMUL_EXAMINE_STRTAB_FOR_CTF): Likewise.
	* emultempl/aix.em (ld_${EMULATION_NAME}_emulation): Add
	emit_ctf_early and examine_strtab_for_ctf, NULL by default.
	* emultempl/armcoff.em (ld_${EMULATION_NAME}_emulation): Likewise.
	* emultempl/beos.em (ld_${EMULATION_NAME}_emulation): Likewise.
	* emultempl/elf.em (ld_${EMULATION_NAME}_emulation): Likewise.
	* emultempl/generic.em (ld_${EMULATION_NAME}_emulation): Likewise.
	* emultempl/linux.em (ld_${EMULATION_NAME}_emulation): Likewise.
	* emultempl/msp430.em (ld_${EMULATION_NAME}_emulation): Likewise.
	* emultempl/pe.em (ld_${EMULATION_NAME}_emulation): Likewise.
	* emultempl/pep.em (ld_${EMULATION_NAME}_emulation): Likewise.
	* emultempl/ticoff.em (ld_${EMULATION_NAME}_emulation): Likewise.
	* emultempl/vanilla.em (ld_vanilla_emulation): Likewise.

	* Makefile.am: Pull in libctf (and zlib, a transitive requirement
	for compressed CTF section emission).  Pass it on to DejaGNU.
	* configure.ac: Add AM_ZLIB.
	* aclocal.m4: Added zlib.m4.
	* Makefile.in: Regenerated.
	* testsuite/ld-bootstrap/bootstrap.exp: Use it when relinking ld.
2019-10-03 17:04:56 +01:00

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/* ldmisc.c
Copyright (C) 1991-2019 Free Software Foundation, Inc.
Written by Steve Chamberlain of Cygnus Support.
This file is part of the GNU Binutils.
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 3 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston,
MA 02110-1301, USA. */
#include "sysdep.h"
#include "bfd.h"
#include "bfdlink.h"
#include "libiberty.h"
#include "ctf-api.h"
#include "safe-ctype.h"
#include "filenames.h"
#include "demangle.h"
#include <stdarg.h>
#include "ld.h"
#include "ldmisc.h"
#include "ldexp.h"
#include "ldlang.h"
#include <ldgram.h>
#include "ldlex.h"
#include "ldmain.h"
#include "ldfile.h"
/*
%% literal %
%C clever filename:linenumber with function
%D like %C, but no function name
%E current bfd error or errno
%F error is fatal
%G like %D, but only function name
%H like %C but in addition emit section+offset
%P print program name
%V hex bfd_vma
%W hex bfd_vma with 0x with no leading zeros taking up 8 spaces
%X no object output, fail return
%d integer, like printf
%ld long, like printf
%lu unsigned long, like printf
%p native (host) void* pointer, like printf
%pA section name from a section
%pB filename from a bfd
%pI filename from a lang_input_statement_type
%pR info about a relent
%pS print script file and linenumber from etree_type.
%pT symbol name
%s arbitrary string, like printf
%u integer, like printf
%v hex bfd_vma, no leading zeros
*/
void
vfinfo (FILE *fp, const char *fmt, va_list ap, bfd_boolean is_warning)
{
bfd_boolean fatal = FALSE;
const char *scan;
int arg_type;
unsigned int arg_count = 0;
unsigned int arg_no;
union vfinfo_args
{
int i;
long l;
void *p;
bfd_vma v;
struct {
bfd *abfd;
asection *sec;
bfd_vma off;
} reladdr;
enum
{
Bad,
Int,
Long,
Ptr,
Vma,
RelAddr
} type;
} args[9];
for (arg_no = 0; arg_no < sizeof (args) / sizeof (args[0]); arg_no++)
args[arg_no].type = Bad;
arg_count = 0;
scan = fmt;
while (*scan != '\0')
{
while (*scan != '%' && *scan != '\0')
scan++;
if (*scan == '%')
{
scan++;
arg_no = arg_count;
if (*scan != '0' && ISDIGIT (*scan) && scan[1] == '$')
{
arg_no = *scan - '1';
scan += 2;
}
arg_type = Bad;
switch (*scan++)
{
case '\0':
--scan;
break;
case 'V':
case 'v':
case 'W':
arg_type = Vma;
break;
case 's':
arg_type = Ptr;
break;
case 'p':
if (*scan == 'A' || *scan == 'B' || *scan == 'I'
|| *scan == 'R' || *scan == 'S' || *scan == 'T')
scan++;
arg_type = Ptr;
break;
case 'C':
case 'D':
case 'G':
case 'H':
arg_type = RelAddr;
break;
case 'd':
case 'u':
arg_type = Int;
break;
case 'l':
if (*scan == 'd' || *scan == 'u')
{
++scan;
arg_type = Long;
}
break;
default:
break;
}
if (arg_type != Bad)
{
if (arg_no >= sizeof (args) / sizeof (args[0]))
abort ();
args[arg_no].type = arg_type;
++arg_count;
}
}
}
for (arg_no = 0; arg_no < arg_count; arg_no++)
{
switch (args[arg_no].type)
{
case Int:
args[arg_no].i = va_arg (ap, int);
break;
case Long:
args[arg_no].l = va_arg (ap, long);
break;
case Ptr:
args[arg_no].p = va_arg (ap, void *);
break;
case Vma:
args[arg_no].v = va_arg (ap, bfd_vma);
break;
case RelAddr:
args[arg_no].reladdr.abfd = va_arg (ap, bfd *);
args[arg_no].reladdr.sec = va_arg (ap, asection *);
args[arg_no].reladdr.off = va_arg (ap, bfd_vma);
break;
default:
abort ();
}
}
arg_count = 0;
while (*fmt != '\0')
{
const char *str = fmt;
while (*fmt != '%' && *fmt != '\0')
fmt++;
if (fmt != str)
if (fwrite (str, 1, fmt - str, fp))
{
/* Ignore. */
}
if (*fmt == '%')
{
fmt++;
arg_no = arg_count;
if (*fmt != '0' && ISDIGIT (*fmt) && fmt[1] == '$')
{
arg_no = *fmt - '1';
fmt += 2;
}
switch (*fmt++)
{
case '\0':
--fmt;
/* Fall through. */
case '%':
/* literal % */
putc ('%', fp);
break;
case 'X':
/* no object output, fail return */
config.make_executable = FALSE;
break;
case 'V':
/* hex bfd_vma */
{
bfd_vma value = args[arg_no].v;
++arg_count;
fprintf_vma (fp, value);
}
break;
case 'v':
/* hex bfd_vma, no leading zeros */
{
char buf[100];
char *p = buf;
bfd_vma value = args[arg_no].v;
++arg_count;
sprintf_vma (p, value);
while (*p == '0')
p++;
if (!*p)
p--;
fputs (p, fp);
}
break;
case 'W':
/* hex bfd_vma with 0x with no leading zeroes taking up
8 spaces. */
{
char buf[100];
bfd_vma value;
char *p;
int len;
value = args[arg_no].v;
++arg_count;
sprintf_vma (buf, value);
for (p = buf; *p == '0'; ++p)
;
if (*p == '\0')
--p;
len = strlen (p);
while (len < 8)
{
putc (' ', fp);
++len;
}
fprintf (fp, "0x%s", p);
}
break;
case 'F':
/* Error is fatal. */
fatal = TRUE;
break;
case 'P':
/* Print program name. */
fprintf (fp, "%s", program_name);
break;
case 'E':
/* current bfd error or errno */
fprintf (fp, "%s", bfd_errmsg (bfd_get_error ()));
break;
case 'C':
case 'D':
case 'G':
case 'H':
/* Clever filename:linenumber with function name if possible.
The arguments are a BFD, a section, and an offset. */
{
static bfd *last_bfd;
static char *last_file;
static char *last_function;
bfd *abfd;
asection *section;
bfd_vma offset;
asymbol **asymbols = NULL;
const char *filename;
const char *functionname;
unsigned int linenumber;
bfd_boolean discard_last;
bfd_boolean done;
abfd = args[arg_no].reladdr.abfd;
section = args[arg_no].reladdr.sec;
offset = args[arg_no].reladdr.off;
++arg_count;
if (abfd != NULL)
{
if (!bfd_generic_link_read_symbols (abfd))
einfo (_("%F%P: %pB: could not read symbols: %E\n"), abfd);
asymbols = bfd_get_outsymbols (abfd);
}
/* The GNU Coding Standard requires that error messages
be of the form:
source-file-name:lineno: message
We do not always have a line number available so if
we cannot find them we print out the section name and
offset instead. */
discard_last = TRUE;
if (abfd != NULL
&& bfd_find_nearest_line (abfd, section, asymbols, offset,
&filename, &functionname,
&linenumber))
{
if (functionname != NULL
&& (fmt[-1] == 'C' || fmt[-1] == 'H'))
{
/* Detect the case where we are printing out a
message for the same function as the last
call to vinfo ("%C"). In this situation do
not print out the ABFD filename or the
function name again. Note - we do still
print out the source filename, as this will
allow programs that parse the linker's output
(eg emacs) to correctly locate multiple
errors in the same source file. */
if (last_bfd == NULL
|| last_function == NULL
|| last_bfd != abfd
|| (last_file == NULL) != (filename == NULL)
|| (filename != NULL
&& filename_cmp (last_file, filename) != 0)
|| strcmp (last_function, functionname) != 0)
{
lfinfo (fp, _("%pB: in function `%pT':\n"),
abfd, functionname);
last_bfd = abfd;
if (last_file != NULL)
free (last_file);
last_file = NULL;
if (filename)
last_file = xstrdup (filename);
if (last_function != NULL)
free (last_function);
last_function = xstrdup (functionname);
}
discard_last = FALSE;
}
else
lfinfo (fp, "%pB:", abfd);
if (filename != NULL)
fprintf (fp, "%s:", filename);
done = fmt[-1] != 'H';
if (functionname != NULL && fmt[-1] == 'G')
lfinfo (fp, "%pT", functionname);
else if (filename != NULL && linenumber != 0)
fprintf (fp, "%u%s", linenumber, done ? "" : ":");
else
done = FALSE;
}
else
{
lfinfo (fp, "%pB:", abfd);
done = FALSE;
}
if (!done)
lfinfo (fp, "(%pA+0x%v)", section, offset);
if (discard_last)
{
last_bfd = NULL;
if (last_file != NULL)
{
free (last_file);
last_file = NULL;
}
if (last_function != NULL)
{
free (last_function);
last_function = NULL;
}
}
}
break;
case 'p':
if (*fmt == 'A')
{
/* section name from a section */
asection *sec;
bfd *abfd;
fmt++;
sec = (asection *) args[arg_no].p;
++arg_count;
fprintf (fp, "%s", sec->name);
abfd = sec->owner;
if (abfd != NULL)
{
const char *group = bfd_group_name (abfd, sec);
if (group != NULL)
fprintf (fp, "[%s]", group);
}
}
else if (*fmt == 'B')
{
/* filename from a bfd */
bfd *abfd = (bfd *) args[arg_no].p;
fmt++;
++arg_count;
if (abfd == NULL)
fprintf (fp, "%s generated", program_name);
else if (abfd->my_archive != NULL
&& !bfd_is_thin_archive (abfd->my_archive))
fprintf (fp, "%s(%s)", abfd->my_archive->filename,
abfd->filename);
else
fprintf (fp, "%s", abfd->filename);
}
else if (*fmt == 'I')
{
/* filename from a lang_input_statement_type */
lang_input_statement_type *i;
fmt++;
i = (lang_input_statement_type *) args[arg_no].p;
++arg_count;
if (i->the_bfd != NULL
&& i->the_bfd->my_archive != NULL
&& !bfd_is_thin_archive (i->the_bfd->my_archive))
fprintf (fp, "(%s)%s", i->the_bfd->my_archive->filename,
i->local_sym_name);
else
fprintf (fp, "%s", i->filename);
}
else if (*fmt == 'R')
{
/* Print all that's interesting about a relent. */
arelent *relent = (arelent *) args[arg_no].p;
fmt++;
++arg_count;
lfinfo (fp, "%s+0x%v (type %s)",
(*(relent->sym_ptr_ptr))->name,
relent->addend,
relent->howto->name);
}
else if (*fmt == 'S')
{
/* Print script file and linenumber. */
etree_type node;
etree_type *tp = (etree_type *) args[arg_no].p;
fmt++;
++arg_count;
if (tp == NULL)
{
tp = &node;
tp->type.filename = ldlex_filename ();
tp->type.lineno = lineno;
}
if (tp->type.filename != NULL)
fprintf (fp, "%s:%u", tp->type.filename, tp->type.lineno);
}
else if (*fmt == 'T')
{
/* Symbol name. */
const char *name = (const char *) args[arg_no].p;
fmt++;
++arg_count;
if (name == NULL || *name == 0)
{
fprintf (fp, _("no symbol"));
break;
}
else if (demangling)
{
char *demangled;
demangled = bfd_demangle (link_info.output_bfd, name,
DMGL_ANSI | DMGL_PARAMS);
if (demangled != NULL)
{
fprintf (fp, "%s", demangled);
free (demangled);
break;
}
}
fprintf (fp, "%s", name);
}
else
{
/* native (host) void* pointer, like printf */
fprintf (fp, "%p", args[arg_no].p);
++arg_count;
}
break;
case 's':
/* arbitrary string, like printf */
fprintf (fp, "%s", (char *) args[arg_no].p);
++arg_count;
break;
case 'd':
/* integer, like printf */
fprintf (fp, "%d", args[arg_no].i);
++arg_count;
break;
case 'u':
/* unsigned integer, like printf */
fprintf (fp, "%u", args[arg_no].i);
++arg_count;
break;
case 'l':
if (*fmt == 'd')
{
fprintf (fp, "%ld", args[arg_no].l);
++arg_count;
++fmt;
break;
}
else if (*fmt == 'u')
{
fprintf (fp, "%lu", args[arg_no].l);
++arg_count;
++fmt;
break;
}
/* Fallthru */
default:
fprintf (fp, "%%%c", fmt[-1]);
break;
}
}
}
if (is_warning && config.fatal_warnings)
config.make_executable = FALSE;
if (fatal)
xexit (1);
}
/* Format info message and print on stdout. */
/* (You would think this should be called just "info", but then you
would be hosed by LynxOS, which defines that name in its libc.) */
void
info_msg (const char *fmt, ...)
{
va_list arg;
va_start (arg, fmt);
vfinfo (stdout, fmt, arg, FALSE);
va_end (arg);
}
/* ('e' for error.) Format info message and print on stderr. */
void
einfo (const char *fmt, ...)
{
va_list arg;
fflush (stdout);
va_start (arg, fmt);
vfinfo (stderr, fmt, arg, TRUE);
va_end (arg);
fflush (stderr);
}
void
info_assert (const char *file, unsigned int line)
{
einfo (_("%F%P: internal error %s %d\n"), file, line);
}
/* ('m' for map) Format info message and print on map. */
void
minfo (const char *fmt, ...)
{
if (config.map_file != NULL)
{
va_list arg;
va_start (arg, fmt);
if (fmt[0] == '%' && fmt[1] == '!' && fmt[2] == 0)
{
/* Stash info about --as-needed shared libraries. Print
later so they don't appear intermingled with archive
library info. */
struct asneeded_minfo *m = xmalloc (sizeof *m);
m->next = NULL;
m->soname = va_arg (arg, const char *);
m->ref = va_arg (arg, bfd *);
m->name = va_arg (arg, const char *);
*asneeded_list_tail = m;
asneeded_list_tail = &m->next;
}
else
vfinfo (config.map_file, fmt, arg, FALSE);
va_end (arg);
}
}
void
lfinfo (FILE *file, const char *fmt, ...)
{
va_list arg;
va_start (arg, fmt);
vfinfo (file, fmt, arg, FALSE);
va_end (arg);
}
/* Functions to print the link map. */
void
print_space (void)
{
fprintf (config.map_file, " ");
}
void
print_nl (void)
{
fprintf (config.map_file, "\n");
}
/* A more or less friendly abort message. In ld.h abort is defined to
call this function. */
void
ld_abort (const char *file, int line, const char *fn)
{
if (fn != NULL)
einfo (_("%P: internal error: aborting at %s:%d in %s\n"),
file, line, fn);
else
einfo (_("%P: internal error: aborting at %s:%d\n"),
file, line);
einfo (_("%F%P: please report this bug\n"));
xexit (1);
}