binutils-gdb/ld/ldmain.c

/* Main program of GNU linker.
   Copyright (C) 1991-2020 Free Software Foundation, Inc.
   Written by Steve Chamberlain steve@cygnus.com

   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 "safe-ctype.h"
#include "libiberty.h"
#include "progress.h"
#include "bfdlink.h"
#include "ctf-api.h"
#include "filenames.h"
#include "elf/common.h"

#include "ld.h"
#include "ldmain.h"
#include "ldmisc.h"
#include "ldwrite.h"
#include "ldexp.h"
#include "ldlang.h"
#include <ldgram.h>
#include "ldlex.h"
#include "ldfile.h"
#include "ldemul.h"
#include "ldctor.h"
#if BFD_SUPPORTS_PLUGINS
#include "plugin.h"
#include "plugin-api.h"
#endif /* BFD_SUPPORTS_PLUGINS */

/* Somewhere above, sys/stat.h got included.  */
#if !defined(S_ISDIR) && defined(S_IFDIR)
#define	S_ISDIR(m) (((m) & S_IFMT) == S_IFDIR)
#endif

#include <string.h>

#ifndef TARGET_SYSTEM_ROOT
#define TARGET_SYSTEM_ROOT ""
#endif

/* EXPORTS */

FILE *saved_script_handle = NULL;
FILE *previous_script_handle = NULL;
bfd_boolean force_make_executable = FALSE;

char *default_target;
const char *output_filename = "a.out";

/* Name this program was invoked by.  */
char *program_name;

/* The prefix for system library directories.  */
const char *ld_sysroot;

/* The canonical representation of ld_sysroot.  */
char *ld_canon_sysroot;
int ld_canon_sysroot_len;

/* Set by -G argument, for targets like MIPS ELF.  */
int g_switch_value = 8;

/* Nonzero means print names of input files as processed.  */
unsigned int trace_files;

/* Nonzero means report actions taken by the linker, and describe the linker script in use.  */
bfd_boolean verbose;

/* Nonzero means version number was printed, so exit successfully
   instead of complaining if no input files are given.  */
bfd_boolean version_printed;

/* TRUE if we should demangle symbol names.  */
bfd_boolean demangling;

args_type command_line;

ld_config_type config;

sort_type sort_section;

static const char *get_sysroot
  (int, char **);
static char *get_emulation
  (int, char **);
static bfd_boolean add_archive_element
  (struct bfd_link_info *, bfd *, const char *, bfd **);
static void multiple_definition
  (struct bfd_link_info *, struct bfd_link_hash_entry *,
   bfd *, asection *, bfd_vma);
static void multiple_common
  (struct bfd_link_info *, struct bfd_link_hash_entry *,
   bfd *, enum bfd_link_hash_type, bfd_vma);
static void add_to_set
  (struct bfd_link_info *, struct bfd_link_hash_entry *,
   bfd_reloc_code_real_type, bfd *, asection *, bfd_vma);
static void constructor_callback
  (struct bfd_link_info *, bfd_boolean, const char *, bfd *,
   asection *, bfd_vma);
static void warning_callback
  (struct bfd_link_info *, const char *, const char *, bfd *,
   asection *, bfd_vma);
static void warning_find_reloc
  (bfd *, asection *, void *);
static void undefined_symbol
  (struct bfd_link_info *, const char *, bfd *, asection *, bfd_vma,
   bfd_boolean);
static void reloc_overflow
  (struct bfd_link_info *, struct bfd_link_hash_entry *, const char *,
   const char *, bfd_vma, bfd *, asection *, bfd_vma);
static void reloc_dangerous
  (struct bfd_link_info *, const char *, bfd *, asection *, bfd_vma);
static void unattached_reloc
  (struct bfd_link_info *, const char *, bfd *, asection *, bfd_vma);
static bfd_boolean notice
  (struct bfd_link_info *, struct bfd_link_hash_entry *,
   struct bfd_link_hash_entry *, bfd *, asection *, bfd_vma, flagword);

static struct bfd_link_callbacks link_callbacks =
{
  add_archive_element,
  multiple_definition,
  multiple_common,
  add_to_set,
  constructor_callback,
  warning_callback,
  undefined_symbol,
  reloc_overflow,
  reloc_dangerous,
  unattached_reloc,
  notice,
  einfo,
  info_msg,
  minfo,
  ldlang_override_segment_assignment,
  ldlang_ctf_apply_strsym,
  ldlang_write_ctf_late
};

static bfd_assert_handler_type default_bfd_assert_handler;
static bfd_error_handler_type default_bfd_error_handler;

struct bfd_link_info link_info;

struct dependency_file
{
  struct dependency_file *next;
  char *name;
};

static struct dependency_file *dependency_files, *dependency_files_tail;

void
track_dependency_files (const char *filename)
{
  struct dependency_file *dep
    = (struct dependency_file *) xmalloc (sizeof (*dep));
  dep->name = xstrdup (filename);
  dep->next = NULL;
  if (dependency_files == NULL)
    dependency_files = dep;
  else
    dependency_files_tail->next = dep;
  dependency_files_tail = dep;
}

static void
write_dependency_file (void)
{
  FILE *out;
  struct dependency_file *dep;

  out = fopen (config.dependency_file, FOPEN_WT);
  if (out == NULL)
    {
      einfo (_("%F%P: cannot open dependency file %s: %E\n"),
	     config.dependency_file);
    }

  fprintf (out, "%s:", output_filename);

  for (dep = dependency_files; dep != NULL; dep = dep->next)
    fprintf (out, " \\\n  %s", dep->name);

  fprintf (out, "\n");
  for (dep = dependency_files; dep != NULL; dep = dep->next)
    fprintf (out, "\n%s:\n", dep->name);

  fclose (out);
}

static void
ld_cleanup (void)
{
  bfd_cache_close_all ();
#if BFD_SUPPORTS_PLUGINS
  plugin_call_cleanup ();
#endif
  if (output_filename && delete_output_file_on_failure)
    unlink_if_ordinary (output_filename);
}

/* Hook to notice BFD assertions.  */

static void
ld_bfd_assert_handler (const char *fmt, const char *bfdver,
		       const char *file, int line)
{
  config.make_executable = FALSE;
  (*default_bfd_assert_handler) (fmt, bfdver, file, line);
}

/* Hook the bfd error/warning handler for --fatal-warnings.  */

static void
ld_bfd_error_handler (const char *fmt, va_list ap)
{
  if (config.fatal_warnings)
    config.make_executable = FALSE;
  (*default_bfd_error_handler) (fmt, ap);
}

int
main (int argc, char **argv)
{
  char *emulation;
  long start_time = get_run_time ();

#if defined (HAVE_SETLOCALE) && defined (HAVE_LC_MESSAGES)
  setlocale (LC_MESSAGES, "");
#endif
#if defined (HAVE_SETLOCALE)
  setlocale (LC_CTYPE, "");
#endif
  bindtextdomain (PACKAGE, LOCALEDIR);
  textdomain (PACKAGE);

#if 0
  /* FIXME: without this hack bfd.mo will be searched in `/usr/share/locale/.../
     LC_MESSAGES/' ignoring the prefix at which it's actually installed! The
     same probably applies to other ld dependencies: libiberty, libopcodes,
     . . . What a drawback in localization it is!  */
  bindtextdomain ("bfd", LOCALEDIR);
#endif /* 0  */

  program_name = argv[0];
  xmalloc_set_program_name (program_name);

  START_PROGRESS (program_name, 0);

  expandargv (&argc, &argv);

  if (bfd_init () != BFD_INIT_MAGIC)
    einfo (_("%F%P: fatal error: libbfd ABI mismatch\n"));

  bfd_set_error_program_name (program_name);

  /* We want to notice and fail on those nasty BFD assertions which are
     likely to signal incorrect output being generated but otherwise may
     leave no trace.  */
  default_bfd_assert_handler = bfd_set_assert_handler (ld_bfd_assert_handler);

  /* Also hook the bfd error/warning handler for --fatal-warnings.  */
  default_bfd_error_handler = bfd_set_error_handler (ld_bfd_error_handler);

  xatexit (ld_cleanup);

  /* Set up the sysroot directory.  */
  ld_sysroot = get_sysroot (argc, argv);
  if (*ld_sysroot)
    ld_canon_sysroot = lrealpath (ld_sysroot);
  if (ld_canon_sysroot)
    {
      ld_canon_sysroot_len = strlen (ld_canon_sysroot);

      /* is_sysrooted_pathname() relies on no trailing dirsep.  */
      if (ld_canon_sysroot_len > 0
	  && IS_DIR_SEPARATOR (ld_canon_sysroot [ld_canon_sysroot_len - 1]))
	ld_canon_sysroot [--ld_canon_sysroot_len] = '\0';
    }
  else
    ld_canon_sysroot_len = -1;

  /* Set the default BFD target based on the configured target.  Doing
     this permits the linker to be configured for a particular target,
     and linked against a shared BFD library which was configured for
     a different target.  The macro TARGET is defined by Makefile.  */
  if (!bfd_set_default_target (TARGET))
    {
      einfo (_("%X%P: can't set BFD default target to `%s': %E\n"), TARGET);
      xexit (1);
    }

#if YYDEBUG
  {
    extern int yydebug;
    yydebug = 1;
  }
#endif

  config.build_constructors = TRUE;
  config.rpath_separator = ':';
  config.split_by_reloc = (unsigned) -1;
  config.split_by_file = (bfd_size_type) -1;
  config.make_executable = TRUE;
  config.magic_demand_paged = TRUE;
  config.text_read_only = TRUE;
  config.print_map_discarded = TRUE;
  link_info.disable_target_specific_optimizations = -1;

  command_line.warn_mismatch = TRUE;
  command_line.warn_search_mismatch = TRUE;
  command_line.check_section_addresses = -1;

  /* We initialize DEMANGLING based on the environment variable
     COLLECT_NO_DEMANGLE.  The gcc collect2 program will demangle the
     output of the linker, unless COLLECT_NO_DEMANGLE is set in the
     environment.  Acting the same way here lets us provide the same
     interface by default.  */
  demangling = getenv ("COLLECT_NO_DEMANGLE") == NULL;

  link_info.allow_undefined_version = TRUE;
  link_info.keep_memory = TRUE;
  link_info.combreloc = TRUE;
  link_info.strip_discarded = TRUE;
  link_info.prohibit_multiple_definition_absolute = FALSE;
  link_info.textrel_check = DEFAULT_LD_TEXTREL_CHECK;
  link_info.emit_hash = DEFAULT_EMIT_SYSV_HASH;
  link_info.emit_gnu_hash = DEFAULT_EMIT_GNU_HASH;
  link_info.callbacks = &link_callbacks;
  link_info.input_bfds_tail = &link_info.input_bfds;
  /* SVR4 linkers seem to set DT_INIT and DT_FINI based on magic _init
     and _fini symbols.  We are compatible.  */
  link_info.init_function = "_init";
  link_info.fini_function = "_fini";
  link_info.relax_pass = 1;
  link_info.extern_protected_data = -1;
  link_info.dynamic_undefined_weak = -1;
  link_info.pei386_auto_import = -1;
  link_info.spare_dynamic_tags = 5;
  link_info.path_separator = ':';
#ifdef DEFAULT_FLAG_COMPRESS_DEBUG
  link_info.compress_debug = COMPRESS_DEBUG_GABI_ZLIB;
#endif
#ifdef DEFAULT_NEW_DTAGS
  link_info.new_dtags = DEFAULT_NEW_DTAGS;
#endif
  link_info.start_stop_visibility = STV_PROTECTED;

  ldfile_add_arch ("");
  emulation = get_emulation (argc, argv);
  ldemul_choose_mode (emulation);
  default_target = ldemul_choose_target (argc, argv);
  lang_init ();
  ldexp_init ();
  ldemul_before_parse ();
  lang_has_input_file = FALSE;
  parse_args (argc, argv);

  if (config.hash_table_size != 0)
    bfd_hash_set_default_size (config.hash_table_size);

#if BFD_SUPPORTS_PLUGINS
  /* Now all the plugin arguments have been gathered, we can load them.  */
  plugin_load_plugins ();
#endif /* BFD_SUPPORTS_PLUGINS */

  ldemul_set_symbols ();

  /* If we have not already opened and parsed a linker script,
     try the default script from command line first.  */
  if (saved_script_handle == NULL
      && command_line.default_script != NULL)
    {
      ldfile_open_script_file (command_line.default_script);
      parser_input = input_script;
      yyparse ();
    }

  /* If we have not already opened and parsed a linker script
     read the emulation's appropriate default script.  */
  if (saved_script_handle == NULL)
    {
      int isfile;
      char *s = ldemul_get_script (&isfile);

      if (isfile)
	ldfile_open_default_command_file (s);
      else
	{
	  lex_string = s;
	  lex_redirect (s, _("built in linker script"), 1);
	}
      parser_input = input_script;
      yyparse ();
      lex_string = NULL;
    }

  if (verbose)
    {
      if (saved_script_handle)
	info_msg (_("using external linker script:"));
      else
	info_msg (_("using internal linker script:"));
      info_msg ("\n==================================================\n");

      if (saved_script_handle)
	{
	  static const int ld_bufsz = 8193;
	  size_t n;
	  char *buf = (char *) xmalloc (ld_bufsz);

	  rewind (saved_script_handle);
	  while ((n = fread (buf, 1, ld_bufsz - 1, saved_script_handle)) > 0)
	    {
	      buf[n] = 0;
	      info_msg ("%s", buf);
	    }
	  rewind (saved_script_handle);
	  free (buf);
	}
      else
	{
	  int isfile;

	  info_msg (ldemul_get_script (&isfile));
	}

      info_msg ("\n==================================================\n");
    }

  if (command_line.force_group_allocation
      || !bfd_link_relocatable (&link_info))
    link_info.resolve_section_groups = TRUE;
  else
    link_info.resolve_section_groups = FALSE;

  if (command_line.print_output_format)
    info_msg ("%s\n", lang_get_output_target ());

  lang_final ();

  /* If the only command line argument has been -v or --version or --verbose
     then ignore any input files provided by linker scripts and exit now.
     We do not want to create an output file when the linker is just invoked
     to provide version information.  */
  if (argc == 2 && version_printed)
    xexit (0);

  if (link_info.inhibit_common_definition && !bfd_link_dll (&link_info))
    einfo (_("%F%P: --no-define-common may not be used without -shared\n"));

  if (!lang_has_input_file)
    {
      if (version_printed || command_line.print_output_format)
	xexit (0);
      einfo (_("%F%P: no input files\n"));
    }

  if (verbose)
    info_msg (_("%P: mode %s\n"), emulation);

  ldemul_after_parse ();

  if (config.map_filename)
    {
      if (strcmp (config.map_filename, "-") == 0)
	{
	  config.map_file = stdout;
	}
      else
	{
	  config.map_file = fopen (config.map_filename, FOPEN_WT);
	  if (config.map_file == (FILE *) NULL)
	    {
	      bfd_set_error (bfd_error_system_call);
	      einfo (_("%F%P: cannot open map file %s: %E\n"),
		     config.map_filename);
	    }
	}
      link_info.has_map_file = TRUE;
    }

  lang_process ();

  /* Print error messages for any missing symbols, for any warning
     symbols, and possibly multiple definitions.  */
  if (bfd_link_relocatable (&link_info))
    link_info.output_bfd->flags &= ~EXEC_P;
  else
    link_info.output_bfd->flags |= EXEC_P;

  if ((link_info.compress_debug & COMPRESS_DEBUG))
    {
      link_info.output_bfd->flags |= BFD_COMPRESS;
      if (link_info.compress_debug == COMPRESS_DEBUG_GABI_ZLIB)
	link_info.output_bfd->flags |= BFD_COMPRESS_GABI;
    }

  ldwrite ();

  if (config.map_file != NULL)
    lang_map ();
  if (command_line.cref)
    output_cref (config.map_file != NULL ? config.map_file : stdout);
  if (nocrossref_list != NULL)
    check_nocrossrefs ();
  if (command_line.print_memory_usage)
    lang_print_memory_usage ();
#if 0
  {
    struct bfd_link_hash_entry *h;

    h = bfd_link_hash_lookup (link_info.hash, "__image_base__", 0,0,1);
    fprintf (stderr, "lookup = %p val %lx\n", h, h ? h->u.def.value : 1);
  }
#endif
  ldexp_finish ();
  lang_finish ();

  if (config.dependency_file != NULL)
    write_dependency_file ();

  /* Even if we're producing relocatable output, some non-fatal errors should
     be reported in the exit status.  (What non-fatal errors, if any, do we
     want to ignore for relocatable output?)  */
  if (!config.make_executable && !force_make_executable)
    {
      if (verbose)
	einfo (_("%P: link errors found, deleting executable `%s'\n"),
	       output_filename);

      /* The file will be removed by ld_cleanup.  */
      xexit (1);
    }
  else
    {
      if (!bfd_close (link_info.output_bfd))
	einfo (_("%F%P: %pB: final close failed: %E\n"), link_info.output_bfd);

      /* If the --force-exe-suffix is enabled, and we're making an
	 executable file and it doesn't end in .exe, copy it to one
	 which does.  */
      if (!bfd_link_relocatable (&link_info)
	  && command_line.force_exe_suffix)
	{
	  int len = strlen (output_filename);

	  if (len < 4
	      || (strcasecmp (output_filename + len - 4, ".exe") != 0
		  && strcasecmp (output_filename + len - 4, ".dll") != 0))
	    {
	      FILE *src;
	      FILE *dst;
	      const int bsize = 4096;
	      char *buf = (char *) xmalloc (bsize);
	      int l;
	      char *dst_name = (char *) xmalloc (len + 5);

	      strcpy (dst_name, output_filename);
	      strcat (dst_name, ".exe");
	      src = fopen (output_filename, FOPEN_RB);
	      dst = fopen (dst_name, FOPEN_WB);

	      if (!src)
		einfo (_("%F%P: unable to open for source of copy `%s'\n"),
		       output_filename);
	      if (!dst)
		einfo (_("%F%P: unable to open for destination of copy `%s'\n"),
		       dst_name);
	      while ((l = fread (buf, 1, bsize, src)) > 0)
		{
		  int done = fwrite (buf, 1, l, dst);

		  if (done != l)
		    einfo (_("%P: error writing file `%s'\n"), dst_name);
		}

	      fclose (src);
	      if (fclose (dst) == EOF)
		einfo (_("%P: error closing file `%s'\n"), dst_name);
	      free (dst_name);
	      free (buf);
	    }
	}
    }

  END_PROGRESS (program_name);

  if (config.stats)
    {
      long run_time = get_run_time () - start_time;

      fflush (stdout);
      fprintf (stderr, _("%s: total time in link: %ld.%06ld\n"),
	       program_name, run_time / 1000000, run_time % 1000000);
      fflush (stderr);
    }

  /* Prevent ld_cleanup from doing anything, after a successful link.  */
  output_filename = NULL;

  xexit (0);
  return 0;
}

/* If the configured sysroot is relocatable, try relocating it based on
   default prefix FROM.  Return the relocated directory if it exists,
   otherwise return null.  */

static char *
get_relative_sysroot (const char *from ATTRIBUTE_UNUSED)
{
#ifdef TARGET_SYSTEM_ROOT_RELOCATABLE
  char *path;
  struct stat s;

  path = make_relative_prefix (program_name, from, TARGET_SYSTEM_ROOT);
  if (path)
    {
      if (stat (path, &s) == 0 && S_ISDIR (s.st_mode))
	return path;
      free (path);
    }
#endif
  return 0;
}

/* Return the sysroot directory.  Return "" if no sysroot is being used.  */

static const char *
get_sysroot (int argc, char **argv)
{
  int i;
  const char *path = NULL;

  for (i = 1; i < argc; i++)
    if (CONST_STRNEQ (argv[i], "--sysroot="))
      path = argv[i] + strlen ("--sysroot=");

  if (!path)
    path = get_relative_sysroot (BINDIR);

  if (!path)
    path = get_relative_sysroot (TOOLBINDIR);

  if (!path)
    path = TARGET_SYSTEM_ROOT;

  if (IS_DIR_SEPARATOR (*path) && path[1] == 0)
    path = "";

  return path;
}

/* We need to find any explicitly given emulation in order to initialize the
   state that's needed by the lex&yacc argument parser (parse_args).  */

static char *
get_emulation (int argc, char **argv)
{
  char *emulation;
  int i;

  emulation = getenv (EMULATION_ENVIRON);
  if (emulation == NULL)
    emulation = DEFAULT_EMULATION;

  for (i = 1; i < argc; i++)
    {
      if (CONST_STRNEQ (argv[i], "-m"))
	{
	  if (argv[i][2] == '\0')
	    {
	      /* -m EMUL */
	      if (i < argc - 1)
		{
		  emulation = argv[i + 1];
		  i++;
		}
	      else
		einfo (_("%F%P: missing argument to -m\n"));
	    }
	  else if (strcmp (argv[i], "-mips1") == 0
		   || strcmp (argv[i], "-mips2") == 0
		   || strcmp (argv[i], "-mips3") == 0
		   || strcmp (argv[i], "-mips4") == 0
		   || strcmp (argv[i], "-mips5") == 0
		   || strcmp (argv[i], "-mips32") == 0
		   || strcmp (argv[i], "-mips32r2") == 0
		   || strcmp (argv[i], "-mips32r6") == 0
		   || strcmp (argv[i], "-mips64") == 0
		   || strcmp (argv[i], "-mips64r2") == 0
		   || strcmp (argv[i], "-mips64r6") == 0)
	    {
	      /* FIXME: The arguments -mips1, -mips2, -mips3, etc. are
		 passed to the linker by some MIPS compilers.  They
		 generally tell the linker to use a slightly different
		 library path.  Perhaps someday these should be
		 implemented as emulations; until then, we just ignore
		 the arguments and hope that nobody ever creates
		 emulations named ips1, ips2 or ips3.  */
	    }
	  else if (strcmp (argv[i], "-m486") == 0)
	    {
	      /* FIXME: The argument -m486 is passed to the linker on
		 some Linux systems.  Hope that nobody creates an
		 emulation named 486.  */
	    }
	  else
	    {
	      /* -mEMUL */
	      emulation = &argv[i][2];
	    }
	}
    }

  return emulation;
}

void
add_ysym (const char *name)
{
  if (link_info.notice_hash == NULL)
    {
      link_info.notice_hash
	= (struct bfd_hash_table *) xmalloc (sizeof (struct bfd_hash_table));
      if (!bfd_hash_table_init_n (link_info.notice_hash,
				  bfd_hash_newfunc,
				  sizeof (struct bfd_hash_entry),
				  61))
	einfo (_("%F%P: bfd_hash_table_init failed: %E\n"));
    }

  if (bfd_hash_lookup (link_info.notice_hash, name, TRUE, TRUE) == NULL)
    einfo (_("%F%P: bfd_hash_lookup failed: %E\n"));
}

void
add_ignoresym (struct bfd_link_info *info, const char *name)
{
  if (info->ignore_hash == NULL)
    {
      info->ignore_hash = xmalloc (sizeof (struct bfd_hash_table));
      if (!bfd_hash_table_init_n (info->ignore_hash,
				  bfd_hash_newfunc,
				  sizeof (struct bfd_hash_entry),
				  61))
	einfo (_("%F%P: bfd_hash_table_init failed: %E\n"));
    }

  if (bfd_hash_lookup (info->ignore_hash, name, TRUE, TRUE) == NULL)
    einfo (_("%F%P: bfd_hash_lookup failed: %E\n"));
}

/* Record a symbol to be wrapped, from the --wrap option.  */

void
add_wrap (const char *name)
{
  if (link_info.wrap_hash == NULL)
    {
      link_info.wrap_hash
	= (struct bfd_hash_table *) xmalloc (sizeof (struct bfd_hash_table));
      if (!bfd_hash_table_init_n (link_info.wrap_hash,
				  bfd_hash_newfunc,
				  sizeof (struct bfd_hash_entry),
				  61))
	einfo (_("%F%P: bfd_hash_table_init failed: %E\n"));
    }

  if (bfd_hash_lookup (link_info.wrap_hash, name, TRUE, TRUE) == NULL)
    einfo (_("%F%P: bfd_hash_lookup failed: %E\n"));
}

/* Handle the -retain-symbols-file option.  */

void
add_keepsyms_file (const char *filename)
{
  FILE *file;
  char *buf;
  size_t bufsize;
  int c;

  if (link_info.strip == strip_some)
    einfo (_("%X%P: error: duplicate retain-symbols-file\n"));

  file = fopen (filename, "r");
  if (file == NULL)
    {
      bfd_set_error (bfd_error_system_call);
      einfo ("%X%P: %s: %E\n", filename);
      return;
    }

  link_info.keep_hash = (struct bfd_hash_table *)
      xmalloc (sizeof (struct bfd_hash_table));
  if (!bfd_hash_table_init (link_info.keep_hash, bfd_hash_newfunc,
			    sizeof (struct bfd_hash_entry)))
    einfo (_("%F%P: bfd_hash_table_init failed: %E\n"));

  bufsize = 100;
  buf = (char *) xmalloc (bufsize);

  c = getc (file);
  while (c != EOF)
    {
      while (ISSPACE (c))
	c = getc (file);

      if (c != EOF)
	{
	  size_t len = 0;

	  while (!ISSPACE (c) && c != EOF)
	    {
	      buf[len] = c;
	      ++len;
	      if (len >= bufsize)
		{
		  bufsize *= 2;
		  buf = (char *) xrealloc (buf, bufsize);
		}
	      c = getc (file);
	    }

	  buf[len] = '\0';

	  if (bfd_hash_lookup (link_info.keep_hash, buf, TRUE, TRUE) == NULL)
	    einfo (_("%F%P: bfd_hash_lookup for insertion failed: %E\n"));
	}
    }

  if (link_info.strip != strip_none)
    einfo (_("%P: `-retain-symbols-file' overrides `-s' and `-S'\n"));

  free (buf);
  link_info.strip = strip_some;
  fclose (file);
}

/* Callbacks from the BFD linker routines.  */

/* This is called when BFD has decided to include an archive member in
   a link.  */

static bfd_boolean
add_archive_element (struct bfd_link_info *info,
		     bfd *abfd,
		     const char *name,
		     bfd **subsbfd ATTRIBUTE_UNUSED)
{
  lang_input_statement_type *input;
  lang_input_statement_type *parent;
  lang_input_statement_type orig_input;

  input = (lang_input_statement_type *)
      xcalloc (1, sizeof (lang_input_statement_type));
  input->header.type = lang_input_statement_enum;
  input->filename = bfd_get_filename (abfd);
  input->local_sym_name = bfd_get_filename (abfd);
  input->the_bfd = abfd;

  /* Save the original data for trace files/tries below, as plugins
     (if enabled) may possibly alter it to point to a replacement
     BFD, but we still want to output the original BFD filename.  */
  orig_input = *input;
#if BFD_SUPPORTS_PLUGINS
  if (link_info.lto_plugin_active)
    {
      /* We must offer this archive member to the plugins to claim.  */
      plugin_maybe_claim (input);
      if (input->flags.claimed)
	{
	  if (no_more_claiming)
	    {
	      /* Don't claim new IR symbols after all IR symbols have
		 been claimed.  */
	      if (verbose)
		info_msg ("%pI: no new IR symbols to claim\n",
			  &orig_input);
	      input->flags.claimed = 0;
	      return FALSE;
	    }
	  input->flags.claim_archive = TRUE;
	  *subsbfd = input->the_bfd;
	}
    }
#endif /* BFD_SUPPORTS_PLUGINS */

  if (link_info.input_bfds_tail == &input->the_bfd->link.next
      || input->the_bfd->link.next != NULL)
    {
      /* We have already loaded this element, and are attempting to
	 load it again.  This can happen when the archive map doesn't
	 match actual symbols defined by the element.  */
      free (input);
      bfd_set_error (bfd_error_malformed_archive);
      return FALSE;
    }

  /* Set the file_chain pointer of archives to the last element loaded
     from the archive.  See ldlang.c:find_rescan_insertion.  */
  parent = bfd_usrdata (abfd->my_archive);
  if (parent != NULL && !parent->flags.reload)
    parent->next = input;

  ldlang_add_file (input);

  if (config.map_file != NULL)
    {
      static bfd_boolean header_printed;
      struct bfd_link_hash_entry *h;
      bfd *from;
      int len;

      h = bfd_link_hash_lookup (info->hash, name, FALSE, FALSE, TRUE);
      if (h == NULL
	  && info->pei386_auto_import
	  && CONST_STRNEQ (name, "__imp_"))
	h = bfd_link_hash_lookup (info->hash, name + 6, FALSE, FALSE, TRUE);

      if (h == NULL)
	from = NULL;
      else
	{
	  switch (h->type)
	    {
	    default:
	      from = NULL;
	      break;

	    case bfd_link_hash_defined:
	    case bfd_link_hash_defweak:
	      from = h->u.def.section->owner;
	      break;

	    case bfd_link_hash_undefined:
	    case bfd_link_hash_undefweak:
	      from = h->u.undef.abfd;
	      break;

	    case bfd_link_hash_common:
	      from = h->u.c.p->section->owner;
	      break;
	    }
	}

      if (!header_printed)
	{
	  minfo (_("Archive member included to satisfy reference by file (symbol)\n\n"));
	  header_printed = TRUE;
	}

      if (abfd->my_archive == NULL
	  || bfd_is_thin_archive (abfd->my_archive))
	{
	  minfo ("%s", bfd_get_filename (abfd));
	  len = strlen (bfd_get_filename (abfd));
	}
      else
	{
	  minfo ("%s(%s)", bfd_get_filename (abfd->my_archive),
		 bfd_get_filename (abfd));
	  len = (strlen (bfd_get_filename (abfd->my_archive))
		 + strlen (bfd_get_filename (abfd))
		 + 2);
	}

      if (len >= 29)
	{
	  print_nl ();
	  len = 0;
	}
      while (len < 30)
	{
	  print_space ();
	  ++len;
	}

      if (from != NULL)
	minfo ("%pB ", from);
      if (h != NULL)
	minfo ("(%pT)\n", h->root.string);
      else
	minfo ("(%s)\n", name);
    }

  if (verbose
      || trace_files > 1
      || (trace_files && bfd_is_thin_archive (orig_input.the_bfd->my_archive)))
    info_msg ("%pI\n", &orig_input);
  return TRUE;
}

/* This is called when BFD has discovered a symbol which is defined
   multiple times.  */

static void
multiple_definition (struct bfd_link_info *info,
		     struct bfd_link_hash_entry *h,
		     bfd *nbfd,
		     asection *nsec,
		     bfd_vma nval)
{
  const char *name;
  bfd *obfd;
  asection *osec;
  bfd_vma oval;

  if (info->allow_multiple_definition)
    return;

  switch (h->type)
    {
    case bfd_link_hash_defined:
      osec = h->u.def.section;
      oval = h->u.def.value;
      obfd = h->u.def.section->owner;
      break;
    case bfd_link_hash_indirect:
      osec = bfd_ind_section_ptr;
      oval = 0;
      obfd = NULL;
      break;
    default:
      abort ();
    }

  /* Ignore a redefinition of an absolute symbol to the
     same value; it's harmless.  */
  if (h->type == bfd_link_hash_defined
      && bfd_is_abs_section (osec)
      && bfd_is_abs_section (nsec)
      && nval == oval)
    return;

  /* If either section has the output_section field set to
     bfd_abs_section_ptr, it means that the section is being
     discarded, and this is not really a multiple definition at all.
     FIXME: It would be cleaner to somehow ignore symbols defined in
     sections which are being discarded.  */
  if (!info->prohibit_multiple_definition_absolute
      && ((osec->output_section != NULL
	   && ! bfd_is_abs_section (osec)
	   && bfd_is_abs_section (osec->output_section))
	  || (nsec->output_section != NULL
	      && !bfd_is_abs_section (nsec)
	      && bfd_is_abs_section (nsec->output_section))))
    return;

  name = h->root.string;
  if (nbfd == NULL)
    {
      nbfd = obfd;
      nsec = osec;
      nval = oval;
      obfd = NULL;
    }
  einfo (_("%X%P: %C: multiple definition of `%pT'"),
	 nbfd, nsec, nval, name);
  if (obfd != NULL)
    einfo (_("; %D: first defined here"), obfd, osec, oval);
  einfo ("\n");

  if (RELAXATION_ENABLED_BY_USER)
    {
      einfo (_("%P: disabling relaxation; it will not work with multiple definitions\n"));
      DISABLE_RELAXATION;
    }
}

/* This is called when there is a definition of a common symbol, or
   when a common symbol is found for a symbol that is already defined,
   or when two common symbols are found.  We only do something if
   -warn-common was used.  */

static void
multiple_common (struct bfd_link_info *info ATTRIBUTE_UNUSED,
		 struct bfd_link_hash_entry *h,
		 bfd *nbfd,
		 enum bfd_link_hash_type ntype,
		 bfd_vma nsize)
{
  const char *name;
  bfd *obfd;
  enum bfd_link_hash_type otype;
  bfd_vma osize;

  if (!config.warn_common)
    return;

  name = h->root.string;
  otype = h->type;
  if (otype == bfd_link_hash_common)
    {
      obfd = h->u.c.p->section->owner;
      osize = h->u.c.size;
    }
  else if (otype == bfd_link_hash_defined
	   || otype == bfd_link_hash_defweak)
    {
      obfd = h->u.def.section->owner;
      osize = 0;
    }
  else
    {
      /* FIXME: It would nice if we could report the BFD which defined
	 an indirect symbol, but we don't have anywhere to store the
	 information.  */
      obfd = NULL;
      osize = 0;
    }

  if (ntype == bfd_link_hash_defined
      || ntype == bfd_link_hash_defweak
      || ntype == bfd_link_hash_indirect)
    {
      ASSERT (otype == bfd_link_hash_common);
      if (obfd != NULL)
	einfo (_("%P: %pB: warning: definition of `%pT' overriding common"
		 " from %pB\n"),
	       nbfd, name, obfd);
      else
	einfo (_("%P: %pB: warning: definition of `%pT' overriding common\n"),
	       nbfd, name);
    }
  else if (otype == bfd_link_hash_defined
	   || otype == bfd_link_hash_defweak
	   || otype == bfd_link_hash_indirect)
    {
      ASSERT (ntype == bfd_link_hash_common);
      if (obfd != NULL)
	einfo (_("%P: %pB: warning: common of `%pT' overridden by definition"
		 " from %pB\n"),
	       nbfd, name, obfd);
      else
	einfo (_("%P: %pB: warning: common of `%pT' overridden by definition\n"),
	       nbfd, name);
    }
  else
    {
      ASSERT (otype == bfd_link_hash_common && ntype == bfd_link_hash_common);
      if (osize > nsize)
	{
	  if (obfd != NULL)
	    einfo (_("%P: %pB: warning: common of `%pT' overridden"
		     " by larger common from %pB\n"),
		   nbfd, name, obfd);
	  else
	    einfo (_("%P: %pB: warning: common of `%pT' overridden"
		     " by larger common\n"),
		   nbfd, name);
	}
      else if (nsize > osize)
	{
	  if (obfd != NULL)
	    einfo (_("%P: %pB: warning: common of `%pT' overriding"
		     " smaller common from %pB\n"),
		   nbfd, name, obfd);
	  else
	    einfo (_("%P: %pB: warning: common of `%pT' overriding"
		     " smaller common\n"),
		   nbfd, name);
	}
      else
	{
	  if (obfd != NULL)
	    einfo (_("%P: %pB and %pB: warning: multiple common of `%pT'\n"),
		   nbfd, obfd, name);
	  else
	    einfo (_("%P: %pB: warning: multiple common of `%pT'\n"),
		   nbfd, name);
	}
    }
}

/* This is called when BFD has discovered a set element.  H is the
   entry in the linker hash table for the set.  SECTION and VALUE
   represent a value which should be added to the set.  */

static void
add_to_set (struct bfd_link_info *info ATTRIBUTE_UNUSED,
	    struct bfd_link_hash_entry *h,
	    bfd_reloc_code_real_type reloc,
	    bfd *abfd,
	    asection *section,
	    bfd_vma value)
{
  if (config.warn_constructors)
    einfo (_("%P: warning: global constructor %s used\n"),
	   h->root.string);

  if (!config.build_constructors)
    return;

  ldctor_add_set_entry (h, reloc, NULL, section, value);

  if (h->type == bfd_link_hash_new)
    {
      h->type = bfd_link_hash_undefined;
      h->u.undef.abfd = abfd;
      /* We don't call bfd_link_add_undef to add this to the list of
	 undefined symbols because we are going to define it
	 ourselves.  */
    }
}

/* This is called when BFD has discovered a constructor.  This is only
   called for some object file formats--those which do not handle
   constructors in some more clever fashion.  This is similar to
   adding an element to a set, but less general.  */

static void
constructor_callback (struct bfd_link_info *info,
		      bfd_boolean constructor,
		      const char *name,
		      bfd *abfd,
		      asection *section,
		      bfd_vma value)
{
  char *s;
  struct bfd_link_hash_entry *h;
  char set_name[1 + sizeof "__CTOR_LIST__"];

  if (config.warn_constructors)
    einfo (_("%P: warning: global constructor %s used\n"), name);

  if (!config.build_constructors)
    return;

  /* Ensure that BFD_RELOC_CTOR exists now, so that we can give a
     useful error message.  */
  if (bfd_reloc_type_lookup (info->output_bfd, BFD_RELOC_CTOR) == NULL
      && (bfd_link_relocatable (info)
	  || bfd_reloc_type_lookup (abfd, BFD_RELOC_CTOR) == NULL))
    einfo (_("%F%P: BFD backend error: BFD_RELOC_CTOR unsupported\n"));

  s = set_name;
  if (bfd_get_symbol_leading_char (abfd) != '\0')
    *s++ = bfd_get_symbol_leading_char (abfd);
  if (constructor)
    strcpy (s, "__CTOR_LIST__");
  else
    strcpy (s, "__DTOR_LIST__");

  h = bfd_link_hash_lookup (info->hash, set_name, TRUE, TRUE, TRUE);
  if (h == (struct bfd_link_hash_entry *) NULL)
    einfo (_("%F%P: bfd_link_hash_lookup failed: %E\n"));
  if (h->type == bfd_link_hash_new)
    {
      h->type = bfd_link_hash_undefined;
      h->u.undef.abfd = abfd;
      /* We don't call bfd_link_add_undef to add this to the list of
	 undefined symbols because we are going to define it
	 ourselves.  */
    }

  ldctor_add_set_entry (h, BFD_RELOC_CTOR, name, section, value);
}

/* A structure used by warning_callback to pass information through
   bfd_map_over_sections.  */

struct warning_callback_info
{
  bfd_boolean found;
  const char *warning;
  const char *symbol;
  asymbol **asymbols;
};

/* Look through the relocs to see if we can find a plausible address
   for SYMBOL in ABFD.  Return TRUE if found.  Otherwise return FALSE.  */

static bfd_boolean
symbol_warning (const char *warning, const char *symbol, bfd *abfd)
{
  struct warning_callback_info cinfo;

  if (!bfd_generic_link_read_symbols (abfd))
    einfo (_("%F%P: %pB: could not read symbols: %E\n"), abfd);

  cinfo.found = FALSE;
  cinfo.warning = warning;
  cinfo.symbol = symbol;
  cinfo.asymbols = bfd_get_outsymbols (abfd);
  bfd_map_over_sections (abfd, warning_find_reloc, &cinfo);
  return cinfo.found;
}

/* This is called when there is a reference to a warning symbol.  */

static void
warning_callback (struct bfd_link_info *info ATTRIBUTE_UNUSED,
		  const char *warning,
		  const char *symbol,
		  bfd *abfd,
		  asection *section,
		  bfd_vma address)
{
  /* This is a hack to support warn_multiple_gp.  FIXME: This should
     have a cleaner interface, but what?  */
  if (!config.warn_multiple_gp
      && strcmp (warning, "using multiple gp values") == 0)
    return;

  if (section != NULL)
    einfo ("%P: %C: %s%s\n", abfd, section, address, _("warning: "), warning);
  else if (abfd == NULL)
    einfo ("%P: %s%s\n", _("warning: "), warning);
  else if (symbol == NULL)
    einfo ("%P: %pB: %s%s\n", abfd, _("warning: "), warning);
  else if (!symbol_warning (warning, symbol, abfd))
    {
      bfd *b;
      /* Search all input files for a reference to SYMBOL.  */
      for (b = info->input_bfds; b; b = b->link.next)
	if (b != abfd && symbol_warning (warning, symbol, b))
	  return;
      einfo ("%P: %pB: %s%s\n", abfd, _("warning: "), warning);
    }
}

/* This is called by warning_callback for each section.  It checks the
   relocs of the section to see if it can find a reference to the
   symbol which triggered the warning.  If it can, it uses the reloc
   to give an error message with a file and line number.  */

static void
warning_find_reloc (bfd *abfd, asection *sec, void *iarg)
{
  struct warning_callback_info *info = (struct warning_callback_info *) iarg;
  long relsize;
  arelent **relpp;
  long relcount;
  arelent **p, **pend;

  if (info->found)
    return;

  relsize = bfd_get_reloc_upper_bound (abfd, sec);
  if (relsize < 0)
    einfo (_("%F%P: %pB: could not read relocs: %E\n"), abfd);
  if (relsize == 0)
    return;

  relpp = (arelent **) xmalloc (relsize);
  relcount = bfd_canonicalize_reloc (abfd, sec, relpp, info->asymbols);
  if (relcount < 0)
    einfo (_("%F%P: %pB: could not read relocs: %E\n"), abfd);

  p = relpp;
  pend = p + relcount;
  for (; p < pend && *p != NULL; p++)
    {
      arelent *q = *p;

      if (q->sym_ptr_ptr != NULL
	  && *q->sym_ptr_ptr != NULL
	  && strcmp (bfd_asymbol_name (*q->sym_ptr_ptr), info->symbol) == 0)
	{
	  /* We found a reloc for the symbol we are looking for.  */
	  einfo ("%P: %C: %s%s\n", abfd, sec, q->address, _("warning: "),
		 info->warning);
	  info->found = TRUE;
	  break;
	}
    }

  free (relpp);
}

/* This is called when an undefined symbol is found.  */

static void
undefined_symbol (struct bfd_link_info *info,
		  const char *name,
		  bfd *abfd,
		  asection *section,
		  bfd_vma address,
		  bfd_boolean error)
{
  static char *error_name;
  static unsigned int error_count;

#define MAX_ERRORS_IN_A_ROW 5

  if (info->ignore_hash != NULL
      && bfd_hash_lookup (info->ignore_hash, name, FALSE, FALSE) != NULL)
    return;

  if (config.warn_once)
    {
      /* Only warn once about a particular undefined symbol.  */
      add_ignoresym (info, name);
    }

  /* We never print more than a reasonable number of errors in a row
     for a single symbol.  */
  if (error_name != NULL
      && strcmp (name, error_name) == 0)
    ++error_count;
  else
    {
      error_count = 0;
      free (error_name);
      error_name = xstrdup (name);
    }

  if (section != NULL)
    {
      if (error_count < MAX_ERRORS_IN_A_ROW)
	{
	  if (error)
	    einfo (_("%X%P: %C: undefined reference to `%pT'\n"),
		   abfd, section, address, name);
	  else
	    einfo (_("%P: %C: warning: undefined reference to `%pT'\n"),
		   abfd, section, address, name);
	}
      else if (error_count == MAX_ERRORS_IN_A_ROW)
	{
	  if (error)
	    einfo (_("%X%P: %D: more undefined references to `%pT' follow\n"),
		   abfd, section, address, name);
	  else
	    einfo (_("%P: %D: warning: more undefined references to `%pT' follow\n"),
		   abfd, section, address, name);
	}
      else if (error)
	einfo ("%X");
    }
  else
    {
      if (error_count < MAX_ERRORS_IN_A_ROW)
	{
	  if (error)
	    einfo (_("%X%P: %pB: undefined reference to `%pT'\n"),
		   abfd, name);
	  else
	    einfo (_("%P: %pB: warning: undefined reference to `%pT'\n"),
		   abfd, name);
	}
      else if (error_count == MAX_ERRORS_IN_A_ROW)
	{
	  if (error)
	    einfo (_("%X%P: %pB: more undefined references to `%pT' follow\n"),
		   abfd, name);
	  else
	    einfo (_("%P: %pB: warning: more undefined references to `%pT' follow\n"),
		   abfd, name);
	}
      else if (error)
	einfo ("%X");
    }
}

/* Counter to limit the number of relocation overflow error messages
   to print.  Errors are printed as it is decremented.  When it's
   called and the counter is zero, a final message is printed
   indicating more relocations were omitted.  When it gets to -1, no
   such errors are printed.  If it's initially set to a value less
   than -1, all such errors will be printed (--verbose does this).  */

int overflow_cutoff_limit = 10;

/* This is called when a reloc overflows.  */

static void
reloc_overflow (struct bfd_link_info *info,
		struct bfd_link_hash_entry *entry,
		const char *name,
		const char *reloc_name,
		bfd_vma addend,
		bfd *abfd,
		asection *section,
		bfd_vma address)
{
  if (overflow_cutoff_limit == -1)
    return;

  einfo ("%X%H:", abfd, section, address);

  if (overflow_cutoff_limit >= 0
      && overflow_cutoff_limit-- == 0)
    {
      einfo (_(" additional relocation overflows omitted from the output\n"));
      return;
    }

  if (entry)
    {
      while (entry->type == bfd_link_hash_indirect
	     || entry->type == bfd_link_hash_warning)
	entry = entry->u.i.link;
      switch (entry->type)
	{
	case bfd_link_hash_undefined:
	case bfd_link_hash_undefweak:
	  einfo (_(" relocation truncated to fit: "
		   "%s against undefined symbol `%pT'"),
		 reloc_name, entry->root.string);
	  break;
	case bfd_link_hash_defined:
	case bfd_link_hash_defweak:
	  einfo (_(" relocation truncated to fit: "
		   "%s against symbol `%pT' defined in %pA section in %pB"),
		 reloc_name, entry->root.string,
		 entry->u.def.section,
		 entry->u.def.section == bfd_abs_section_ptr
		 ? info->output_bfd : entry->u.def.section->owner);
	  break;
	default:
	  abort ();
	  break;
	}
    }
  else
    einfo (_(" relocation truncated to fit: %s against `%pT'"),
	   reloc_name, name);
  if (addend != 0)
    einfo ("+%v", addend);
  einfo ("\n");
}

/* This is called when a dangerous relocation is made.  */

static void
reloc_dangerous (struct bfd_link_info *info ATTRIBUTE_UNUSED,
		 const char *message,
		 bfd *abfd,
		 asection *section,
		 bfd_vma address)
{
  einfo (_("%X%H: dangerous relocation: %s\n"),
	 abfd, section, address, message);
}

/* This is called when a reloc is being generated attached to a symbol
   that is not being output.  */

static void
unattached_reloc (struct bfd_link_info *info ATTRIBUTE_UNUSED,
		  const char *name,
		  bfd *abfd,
		  asection *section,
		  bfd_vma address)
{
  einfo (_("%X%H: reloc refers to symbol `%pT' which is not being output\n"),
	 abfd, section, address, name);
}

/* This is called if link_info.notice_all is set, or when a symbol in
   link_info.notice_hash is found.  Symbols are put in notice_hash
   using the -y option, while notice_all is set if the --cref option
   has been supplied, or if there are any NOCROSSREFS sections in the
   linker script; and if plugins are active, since they need to monitor
   all references from non-IR files.  */

static bfd_boolean
notice (struct bfd_link_info *info,
	struct bfd_link_hash_entry *h,
	struct bfd_link_hash_entry *inh ATTRIBUTE_UNUSED,
	bfd *abfd,
	asection *section,
	bfd_vma value,
	flagword flags ATTRIBUTE_UNUSED)
{
  const char *name;

  if (h == NULL)
    {
      if (command_line.cref || nocrossref_list != NULL)
	return handle_asneeded_cref (abfd, (enum notice_asneeded_action) value);
      return TRUE;
    }

  name = h->root.string;
  if (info->notice_hash != NULL
      && bfd_hash_lookup (info->notice_hash, name, FALSE, FALSE) != NULL)
    {
      if (bfd_is_und_section (section))
	einfo (_("%P: %pB: reference to %s\n"), abfd, name);
      else
	einfo (_("%P: %pB: definition of %s\n"), abfd, name);
    }

  if (command_line.cref || nocrossref_list != NULL)
    add_cref (name, abfd, section, value);

  return TRUE;
}