gcc/

[thirdparty/gcc.git] / gcc / collect2.c

/* Collect static initialization info into data structures that can be
   traversed by C++ initialization and finalization routines.
   Copyright (C) 1992, 1993, 1994, 1995, 1996, 1997, 1998,
   1999, 2000, 2001, 2002, 2003, 2004, 2005, 2007, 2008, 2009
   Free Software Foundation, Inc.
   Contributed by Chris Smith (csmith@convex.com).
   Heavily modified by Michael Meissner (meissner@cygnus.com),
   Per Bothner (bothner@cygnus.com), and John Gilmore (gnu@cygnus.com).

This file is part of GCC.

GCC 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.

GCC 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 GCC; see the file COPYING3.  If not see
<http://www.gnu.org/licenses/>.  */


/* Build tables of static constructors and destructors and run ld.  */

#include "config.h"
#include "system.h"
#include "coretypes.h"
#include "tm.h"
#include <signal.h>
#if ! defined( SIGCHLD ) && defined( SIGCLD )
#  define SIGCHLD SIGCLD
#endif

#ifndef LIBRARY_PATH_ENV
#define LIBRARY_PATH_ENV "LIBRARY_PATH"
#endif

#define COLLECT

#include "collect2.h"
#include "demangle.h"
#include "obstack.h"
#include "intl.h"
#include "version.h"
\f
/* On certain systems, we have code that works by scanning the object file
   directly.  But this code uses system-specific header files and library
   functions, so turn it off in a cross-compiler.  Likewise, the names of
   the utilities are not correct for a cross-compiler; we have to hope that
   cross-versions are in the proper directories.  */

#ifdef CROSS_DIRECTORY_STRUCTURE
#undef OBJECT_FORMAT_COFF
#undef MD_EXEC_PREFIX
#undef REAL_LD_FILE_NAME
#undef REAL_NM_FILE_NAME
#undef REAL_STRIP_FILE_NAME
#endif

/* If we cannot use a special method, use the ordinary one:
   run nm to find what symbols are present.
   In a cross-compiler, this means you need a cross nm,
   but that is not quite as unpleasant as special headers.  */

#if !defined (OBJECT_FORMAT_COFF)
#define OBJECT_FORMAT_NONE
#endif

#ifdef OBJECT_FORMAT_COFF

#include <a.out.h>
#include <ar.h>

#ifdef UMAX
#include <sgs.h>
#endif

/* Many versions of ldfcn.h define these.  */
#ifdef FREAD
#undef FREAD
#undef FWRITE
#endif

#include <ldfcn.h>

/* Some systems have an ISCOFF macro, but others do not.  In some cases
   the macro may be wrong.  MY_ISCOFF is defined in tm.h files for machines
   that either do not have an ISCOFF macro in /usr/include or for those
   where it is wrong.  */

#ifndef MY_ISCOFF
#define MY_ISCOFF(X) ISCOFF (X)
#endif

#endif /* OBJECT_FORMAT_COFF */

#ifdef OBJECT_FORMAT_NONE

/* Default flags to pass to nm.  */
#ifndef NM_FLAGS
#define NM_FLAGS "-n"
#endif

#endif /* OBJECT_FORMAT_NONE */

/* Some systems use __main in a way incompatible with its use in gcc, in these
   cases use the macros NAME__MAIN to give a quoted symbol and SYMBOL__MAIN to
   give the same symbol without quotes for an alternative entry point.  */
#ifndef NAME__MAIN
#define NAME__MAIN "__main"
#endif

/* This must match tree.h.  */
#define DEFAULT_INIT_PRIORITY 65535

#ifndef COLLECT_SHARED_INIT_FUNC
#define COLLECT_SHARED_INIT_FUNC(STREAM, FUNC) \
  fprintf ((STREAM), "void _GLOBAL__DI() {\n\t%s();\n}\n", (FUNC))
#endif
#ifndef COLLECT_SHARED_FINI_FUNC
#define COLLECT_SHARED_FINI_FUNC(STREAM, FUNC) \
  fprintf ((STREAM), "void _GLOBAL__DD() {\n\t%s();\n}\n", (FUNC))
#endif

#ifdef LDD_SUFFIX
#define SCAN_LIBRARIES
#endif

#ifndef SHLIB_SUFFIX
#define SHLIB_SUFFIX ".so"
#endif

#ifdef USE_COLLECT2
int do_collecting = 1;
#else
int do_collecting = 0;
#endif

/* Nonzero if we should suppress the automatic demangling of identifiers
   in linker error messages.  Set from COLLECT_NO_DEMANGLE.  */
int no_demangle;
\f
/* Linked lists of constructor and destructor names.  */

struct id
{
  struct id *next;
  int sequence;
  char name[1];
};

struct head
{
  struct id *first;
  struct id *last;
  int number;
};

/* Enumeration giving which pass this is for scanning the program file.  */

enum pass {
  PASS_FIRST,                           /* without constructors */
  PASS_OBJ,                             /* individual objects */
  PASS_LIB,                             /* looking for shared libraries */
  PASS_SECOND                           /* with constructors linked in */
};

int vflag;                              /* true if -v */
static int rflag;                       /* true if -r */
static int strip_flag;                  /* true if -s */
static const char *demangle_flag;
#ifdef COLLECT_EXPORT_LIST
static int export_flag;                 /* true if -bE */
static int aix64_flag;                  /* true if -b64 */
static int aixrtl_flag;                 /* true if -brtl */
#endif

int debug;                              /* true if -debug */

static int shared_obj;                  /* true if -shared */

static const char *c_file;              /* <xxx>.c for constructor/destructor list.  */
static const char *o_file;              /* <xxx>.o for constructor/destructor list.  */
#ifdef COLLECT_EXPORT_LIST
static const char *export_file;         /* <xxx>.x for AIX export list.  */
#endif
const char *ldout;                      /* File for ld stdout.  */
const char *lderrout;                   /* File for ld stderr.  */
static const char *output_file;         /* Output file for ld.  */
static const char *nm_file_name;        /* pathname of nm */
#ifdef LDD_SUFFIX
static const char *ldd_file_name;       /* pathname of ldd (or equivalent) */
#endif
static const char *strip_file_name;             /* pathname of strip */
const char *c_file_name;                /* pathname of gcc */
static char *initname, *fininame;       /* names of init and fini funcs */

static struct head constructors;        /* list of constructors found */
static struct head destructors;         /* list of destructors found */
#ifdef COLLECT_EXPORT_LIST
static struct head exports;             /* list of exported symbols */
#endif
static struct head frame_tables;        /* list of frame unwind info tables */

static bool at_file_supplied;           /* Whether to use @file arguments */
static char *response_file;             /* Name of any current response file */

struct obstack temporary_obstack;
char * temporary_firstobj;

/* Structure to hold all the directories in which to search for files to
   execute.  */

struct prefix_list
{
  const char *prefix;         /* String to prepend to the path.  */
  struct prefix_list *next;   /* Next in linked list.  */
};

struct path_prefix
{
  struct prefix_list *plist;  /* List of prefixes to try */
  int max_len;                /* Max length of a prefix in PLIST */
  const char *name;           /* Name of this list (used in config stuff) */
};

#ifdef COLLECT_EXPORT_LIST
/* Lists to keep libraries to be scanned for global constructors/destructors.  */
static struct head libs;                    /* list of libraries */
static struct path_prefix cmdline_lib_dirs; /* directories specified with -L */
static struct path_prefix libpath_lib_dirs; /* directories in LIBPATH */
static struct path_prefix *libpaths[3] = {&cmdline_lib_dirs,
                                          &libpath_lib_dirs, NULL};
#endif

/* Special kinds of symbols that a name may denote.  */

typedef enum {
  SYM_REGULAR = 0,  /* nothing special  */

  SYM_CTOR = 1,  /* constructor */
  SYM_DTOR = 2,  /* destructor  */
  SYM_INIT = 3,  /* shared object routine that calls all the ctors  */
  SYM_FINI = 4,  /* shared object routine that calls all the dtors  */
  SYM_DWEH = 5   /* DWARF exception handling table  */
} symkind;

static symkind is_ctor_dtor (const char *);

static void handler (int);
static char *find_a_file (struct path_prefix *, const char *);
static void add_prefix (struct path_prefix *, const char *);
static void prefix_from_env (const char *, struct path_prefix *);
static void prefix_from_string (const char *, struct path_prefix *);
static void do_wait (const char *, struct pex_obj *);
static void fork_execute (const char *, char **);
static void maybe_unlink (const char *);
static void add_to_list (struct head *, const char *);
static int extract_init_priority (const char *);
static void sort_ids (struct head *);
static void write_list (FILE *, const char *, struct id *);
#ifdef COLLECT_EXPORT_LIST
static void dump_list (FILE *, const char *, struct id *);
#endif
#if 0
static void dump_prefix_list (FILE *, const char *, struct prefix_list *);
#endif
static void write_list_with_asm (FILE *, const char *, struct id *);
static void write_c_file (FILE *, const char *);
static void write_c_file_stat (FILE *, const char *);
#ifndef LD_INIT_SWITCH
static void write_c_file_glob (FILE *, const char *);
#endif
static void scan_prog_file (const char *, enum pass);
#ifdef SCAN_LIBRARIES
static void scan_libraries (const char *);
#endif
#if LINK_ELIMINATE_DUPLICATE_LDIRECTORIES
static int is_in_args (const char *, const char **, const char **);
#endif
#ifdef COLLECT_EXPORT_LIST
#if 0
static int is_in_list (const char *, struct id *);
#endif
static void write_aix_file (FILE *, struct id *);
static char *resolve_lib_name (const char *);
#endif
static char *extract_string (const char **);
\f
/* Delete tempfiles and exit function.  */

void
collect_exit (int status)
{
  if (c_file != 0 && c_file[0])
    maybe_unlink (c_file);

  if (o_file != 0 && o_file[0])
    maybe_unlink (o_file);

#ifdef COLLECT_EXPORT_LIST
  if (export_file != 0 && export_file[0])
    maybe_unlink (export_file);
#endif

  if (ldout != 0 && ldout[0])
    {
      dump_file (ldout, stdout);
      maybe_unlink (ldout);
    }

  if (lderrout != 0 && lderrout[0])
    {
      dump_file (lderrout, stderr);
      maybe_unlink (lderrout);
    }

  if (status != 0 && output_file != 0 && output_file[0])
    maybe_unlink (output_file);

  if (response_file)
    maybe_unlink (response_file);

  exit (status);
}

\f
/* Notify user of a non-error.  */
void
notice (const char *cmsgid, ...)
{
  va_list ap;

  va_start (ap, cmsgid);
  vfprintf (stderr, _(cmsgid), ap);
  va_end (ap);
}

/* Die when sys call fails.  */

void
fatal_perror (const char * cmsgid, ...)
{
  int e = errno;
  va_list ap;

  va_start (ap, cmsgid);
  fprintf (stderr, "collect2: ");
  vfprintf (stderr, _(cmsgid), ap);
  fprintf (stderr, ": %s\n", xstrerror (e));
  va_end (ap);

  collect_exit (FATAL_EXIT_CODE);
}

/* Just die.  */

void
fatal (const char * cmsgid, ...)
{
  va_list ap;

  va_start (ap, cmsgid);
  fprintf (stderr, "collect2: ");
  vfprintf (stderr, _(cmsgid), ap);
  fprintf (stderr, "\n");
  va_end (ap);

  collect_exit (FATAL_EXIT_CODE);
}

/* Write error message.  */

void
error (const char * gmsgid, ...)
{
  va_list ap;

  va_start (ap, gmsgid);
  fprintf (stderr, "collect2: ");
  vfprintf (stderr, _(gmsgid), ap);
  fprintf (stderr, "\n");
  va_end(ap);
}

/* In case obstack is linked in, and abort is defined to fancy_abort,
   provide a default entry.  */

void
fancy_abort (const char *file, int line, const char *func)
{
  fatal ("internal gcc abort in %s, at %s:%d", func, file, line);
}
\f
static void
handler (int signo)
{
  if (c_file != 0 && c_file[0])
    maybe_unlink (c_file);

  if (o_file != 0 && o_file[0])
    maybe_unlink (o_file);

  if (ldout != 0 && ldout[0])
    maybe_unlink (ldout);

  if (lderrout != 0 && lderrout[0])
    maybe_unlink (lderrout);

#ifdef COLLECT_EXPORT_LIST
  if (export_file != 0 && export_file[0])
    maybe_unlink (export_file);
#endif

  if (response_file)
    maybe_unlink (response_file);

  signal (signo, SIG_DFL);
  raise (signo);
}

\f
int
file_exists (const char *name)
{
  return access (name, R_OK) == 0;
}

/* Parse a reasonable subset of shell quoting syntax.  */

static char *
extract_string (const char **pp)
{
  const char *p = *pp;
  int backquote = 0;
  int inside = 0;

  for (;;)
    {
      char c = *p;
      if (c == '\0')
        break;
      ++p;
      if (backquote)
        obstack_1grow (&temporary_obstack, c);
      else if (! inside && c == ' ')
        break;
      else if (! inside && c == '\\')
        backquote = 1;
      else if (c == '\'')
        inside = !inside;
      else
        obstack_1grow (&temporary_obstack, c);
    }

  obstack_1grow (&temporary_obstack, '\0');
  *pp = p;
  return XOBFINISH (&temporary_obstack, char *);
}
\f
void
dump_file (const char *name, FILE *to)
{
  FILE *stream = fopen (name, "r");

  if (stream == 0)
    return;
  while (1)
    {
      int c;
      while (c = getc (stream),
             c != EOF && (ISIDNUM (c) || c == '$' || c == '.'))
        obstack_1grow (&temporary_obstack, c);
      if (obstack_object_size (&temporary_obstack) > 0)
        {
          const char *word, *p;
          char *result;
          obstack_1grow (&temporary_obstack, '\0');
          word = XOBFINISH (&temporary_obstack, const char *);

          if (*word == '.')
            ++word, putc ('.', to);
          p = word;
          if (!strncmp (p, USER_LABEL_PREFIX, strlen (USER_LABEL_PREFIX)))
            p += strlen (USER_LABEL_PREFIX);

#ifdef HAVE_LD_DEMANGLE
          result = 0;
#else
          if (no_demangle)
            result = 0;
          else
            result = cplus_demangle (p, DMGL_PARAMS | DMGL_ANSI | DMGL_VERBOSE);
#endif

          if (result)
            {
              int diff;
              fputs (result, to);

              diff = strlen (word) - strlen (result);
              while (diff > 0 && c == ' ')
                --diff, putc (' ', to);
              if (diff < 0 && c == ' ')
                {
                  while (diff < 0 && c == ' ')
                    ++diff, c = getc (stream);
                  if (!ISSPACE (c))
                    {
                      /* Make sure we output at least one space, or
                         the demangled symbol name will run into
                         whatever text follows.  */
                      putc (' ', to);
                    }
                }

              free (result);
            }
          else
            fputs (word, to);

          fflush (to);
          obstack_free (&temporary_obstack, temporary_firstobj);
        }
      if (c == EOF)
        break;
      putc (c, to);
    }
  fclose (stream);
}
\f
/* Return the kind of symbol denoted by name S.  */

static symkind
is_ctor_dtor (const char *s)
{
  struct names { const char *const name; const int len; symkind ret;
    const int two_underscores; };

  const struct names *p;
  int ch;
  const char *orig_s = s;

  static const struct names special[] = {
#ifndef NO_DOLLAR_IN_LABEL
    { "GLOBAL__I$", sizeof ("GLOBAL__I$")-1, SYM_CTOR, 0 },
    { "GLOBAL__D$", sizeof ("GLOBAL__D$")-1, SYM_DTOR, 0 },
#else
#ifndef NO_DOT_IN_LABEL
    { "GLOBAL__I.", sizeof ("GLOBAL__I.")-1, SYM_CTOR, 0 },
    { "GLOBAL__D.", sizeof ("GLOBAL__D.")-1, SYM_DTOR, 0 },
#endif /* NO_DOT_IN_LABEL */
#endif /* NO_DOLLAR_IN_LABEL */
    { "GLOBAL__I_", sizeof ("GLOBAL__I_")-1, SYM_CTOR, 0 },
    { "GLOBAL__D_", sizeof ("GLOBAL__D_")-1, SYM_DTOR, 0 },
    { "GLOBAL__F_", sizeof ("GLOBAL__F_")-1, SYM_DWEH, 0 },
    { "GLOBAL__FI_", sizeof ("GLOBAL__FI_")-1, SYM_INIT, 0 },
    { "GLOBAL__FD_", sizeof ("GLOBAL__FD_")-1, SYM_FINI, 0 },
    { NULL, 0, SYM_REGULAR, 0 }
  };

  while ((ch = *s) == '_')
    ++s;

  if (s == orig_s)
    return SYM_REGULAR;

  for (p = &special[0]; p->len > 0; p++)
    {
      if (ch == p->name[0]
          && (!p->two_underscores || ((s - orig_s) >= 2))
          && strncmp(s, p->name, p->len) == 0)
        {
          return p->ret;
        }
    }
  return SYM_REGULAR;
}
\f
/* We maintain two prefix lists: one from COMPILER_PATH environment variable
   and one from the PATH variable.  */

static struct path_prefix cpath, path;

#ifdef CROSS_DIRECTORY_STRUCTURE
/* This is the name of the target machine.  We use it to form the name
   of the files to execute.  */

static const char *const target_machine = TARGET_MACHINE;
#endif

/* Search for NAME using prefix list PPREFIX.  We only look for executable
   files.

   Return 0 if not found, otherwise return its name, allocated with malloc.  */

static char *
find_a_file (struct path_prefix *pprefix, const char *name)
{
  char *temp;
  struct prefix_list *pl;
  int len = pprefix->max_len + strlen (name) + 1;

  if (debug)
    fprintf (stderr, "Looking for '%s'\n", name);

#ifdef HOST_EXECUTABLE_SUFFIX
  len += strlen (HOST_EXECUTABLE_SUFFIX);
#endif

  temp = XNEWVEC (char, len);

  /* Determine the filename to execute (special case for absolute paths).  */

  if (IS_ABSOLUTE_PATH (name))
    {
      if (access (name, X_OK) == 0)
        {
          strcpy (temp, name);

          if (debug)
            fprintf (stderr, "  - found: absolute path\n");

          return temp;
        }

#ifdef HOST_EXECUTABLE_SUFFIX
        /* Some systems have a suffix for executable files.
           So try appending that.  */
      strcpy (temp, name);
        strcat (temp, HOST_EXECUTABLE_SUFFIX);

        if (access (temp, X_OK) == 0)
          return temp;
#endif

      if (debug)
        fprintf (stderr, "  - failed to locate using absolute path\n");
    }
  else
    for (pl = pprefix->plist; pl; pl = pl->next)
      {
        struct stat st;

        strcpy (temp, pl->prefix);
        strcat (temp, name);

        if (stat (temp, &st) >= 0
            && ! S_ISDIR (st.st_mode)
            && access (temp, X_OK) == 0)
          return temp;

#ifdef HOST_EXECUTABLE_SUFFIX
        /* Some systems have a suffix for executable files.
           So try appending that.  */
        strcat (temp, HOST_EXECUTABLE_SUFFIX);

        if (stat (temp, &st) >= 0
            && ! S_ISDIR (st.st_mode)
            && access (temp, X_OK) == 0)
          return temp;
#endif
      }

  if (debug && pprefix->plist == NULL)
    fprintf (stderr, "  - failed: no entries in prefix list\n");

  free (temp);
  return 0;
}

/* Add an entry for PREFIX to prefix list PPREFIX.  */

static void
add_prefix (struct path_prefix *pprefix, const char *prefix)
{
  struct prefix_list *pl, **prev;
  int len;

  if (pprefix->plist)
    {
      for (pl = pprefix->plist; pl->next; pl = pl->next)
        ;
      prev = &pl->next;
    }
  else
    prev = &pprefix->plist;

  /* Keep track of the longest prefix.  */

  len = strlen (prefix);
  if (len > pprefix->max_len)
    pprefix->max_len = len;

  pl = XNEW (struct prefix_list);
  pl->prefix = xstrdup (prefix);

  if (*prev)
    pl->next = *prev;
  else
    pl->next = (struct prefix_list *) 0;
  *prev = pl;
}
\f
/* Take the value of the environment variable ENV, break it into a path, and
   add of the entries to PPREFIX.  */

static void
prefix_from_env (const char *env, struct path_prefix *pprefix)
{
  const char *p;
  GET_ENVIRONMENT (p, env);

  if (p)
    prefix_from_string (p, pprefix);
}

static void
prefix_from_string (const char *p, struct path_prefix *pprefix)
{
  const char *startp, *endp;
  char *nstore = XNEWVEC (char, strlen (p) + 3);

  if (debug)
    fprintf (stderr, "Convert string '%s' into prefixes, separator = '%c'\n", p, PATH_SEPARATOR);

  startp = endp = p;
  while (1)
    {
      if (*endp == PATH_SEPARATOR || *endp == 0)
        {
          strncpy (nstore, startp, endp-startp);
          if (endp == startp)
            {
              strcpy (nstore, "./");
            }
          else if (! IS_DIR_SEPARATOR (endp[-1]))
            {
              nstore[endp-startp] = DIR_SEPARATOR;
              nstore[endp-startp+1] = 0;
            }
          else
            nstore[endp-startp] = 0;

          if (debug)
            fprintf (stderr, "  - add prefix: %s\n", nstore);

          add_prefix (pprefix, nstore);
          if (*endp == 0)
            break;
          endp = startp = endp + 1;
        }
      else
        endp++;
    }
  free (nstore);
}
\f
/* Main program.  */

int
main (int argc, char **argv)
{
  static const char *const ld_suffix    = "ld";
  static const char *const real_ld_suffix = "real-ld";
  static const char *const collect_ld_suffix = "collect-ld";
  static const char *const nm_suffix    = "nm";
  static const char *const gnm_suffix   = "gnm";
#ifdef LDD_SUFFIX
  static const char *const ldd_suffix   = LDD_SUFFIX;
#endif
  static const char *const strip_suffix = "strip";
  static const char *const gstrip_suffix = "gstrip";

#ifdef CROSS_DIRECTORY_STRUCTURE
  /* If we look for a program in the compiler directories, we just use
     the short name, since these directories are already system-specific.
     But it we look for a program in the system directories, we need to
     qualify the program name with the target machine.  */

  const char *const full_ld_suffix =
    concat(target_machine, "-", ld_suffix, NULL);
  const char *const full_nm_suffix =
    concat (target_machine, "-", nm_suffix, NULL);
  const char *const full_gnm_suffix =
    concat (target_machine, "-", gnm_suffix, NULL);
#ifdef LDD_SUFFIX
  const char *const full_ldd_suffix =
    concat (target_machine, "-", ldd_suffix, NULL);
#endif
  const char *const full_strip_suffix =
    concat (target_machine, "-", strip_suffix, NULL);
  const char *const full_gstrip_suffix =
    concat (target_machine, "-", gstrip_suffix, NULL);
#else
  const char *const full_ld_suffix      = ld_suffix;
  const char *const full_nm_suffix      = nm_suffix;
  const char *const full_gnm_suffix     = gnm_suffix;
#ifdef LDD_SUFFIX
  const char *const full_ldd_suffix     = ldd_suffix;
#endif
  const char *const full_strip_suffix   = strip_suffix;
  const char *const full_gstrip_suffix  = gstrip_suffix;
#endif /* CROSS_DIRECTORY_STRUCTURE */

  const char *arg;
  FILE *outf;
#ifdef COLLECT_EXPORT_LIST
  FILE *exportf;
#endif
  const char *ld_file_name;
  const char *p;
  char **c_argv;
  const char **c_ptr;
  char **ld1_argv;
  const char **ld1;
  char **ld2_argv;
  const char **ld2;
  char **object_lst;
  const char **object;
  int first_file;
  int num_c_args;
  char **old_argv;

  old_argv = argv;
  expandargv (&argc, &argv);
  if (argv != old_argv)
    at_file_supplied = 1;

  num_c_args = argc + 9;

  no_demangle = !! getenv ("COLLECT_NO_DEMANGLE");

  /* Suppress demangling by the real linker, which may be broken.  */
  putenv (xstrdup ("COLLECT_NO_DEMANGLE="));

#if defined (COLLECT2_HOST_INITIALIZATION)
  /* Perform system dependent initialization, if necessary.  */
  COLLECT2_HOST_INITIALIZATION;
#endif

#ifdef SIGCHLD
  /* We *MUST* set SIGCHLD to SIG_DFL so that the wait4() call will
     receive the signal.  A different setting is inheritable */
  signal (SIGCHLD, SIG_DFL);
#endif

  /* Unlock the stdio streams.  */
  unlock_std_streams ();

  gcc_init_libintl ();

  /* Do not invoke xcalloc before this point, since locale needs to be
     set first, in case a diagnostic is issued.  */

  ld1_argv = XCNEWVEC (char *, argc + 4);
  ld1 = CONST_CAST2 (const char **, char **, ld1_argv);
  ld2_argv = XCNEWVEC (char *, argc + 11);
  ld2 = CONST_CAST2 (const char **, char **, ld2_argv);
  object_lst = XCNEWVEC (char *, argc);
  object = CONST_CAST2 (const char **, char **, object_lst);

#ifdef DEBUG
  debug = 1;
#endif

  /* Parse command line early for instances of -debug.  This allows
     the debug flag to be set before functions like find_a_file()
     are called.  */
  {
    int i;

    for (i = 1; argv[i] != NULL; i ++)
      {
        if (! strcmp (argv[i], "-debug"))
          debug = 1;
      }
    vflag = debug;
  }

#ifndef DEFAULT_A_OUT_NAME
  output_file = "a.out";
#else
  output_file = DEFAULT_A_OUT_NAME;
#endif

  obstack_begin (&temporary_obstack, 0);
  temporary_firstobj = (char *) obstack_alloc (&temporary_obstack, 0);

#ifndef HAVE_LD_DEMANGLE
  current_demangling_style = auto_demangling;
#endif
  p = getenv ("COLLECT_GCC_OPTIONS");
  while (p && *p)
    {
      const char *q = extract_string (&p);
      if (*q == '-' && (q[1] == 'm' || q[1] == 'f'))
        num_c_args++;
    }
  obstack_free (&temporary_obstack, temporary_firstobj);

  /* -fno-profile-arcs -fno-test-coverage -fno-branch-probabilities
     -fno-exceptions -w */
  num_c_args += 5;

  c_argv = XCNEWVEC (char *, num_c_args);
  c_ptr = CONST_CAST2 (const char **, char **, c_argv);

  if (argc < 2)
    fatal ("no arguments");

#ifdef SIGQUIT
  if (signal (SIGQUIT, SIG_IGN) != SIG_IGN)
    signal (SIGQUIT, handler);
#endif
  if (signal (SIGINT, SIG_IGN) != SIG_IGN)
    signal (SIGINT, handler);
#ifdef SIGALRM
  if (signal (SIGALRM, SIG_IGN) != SIG_IGN)
    signal (SIGALRM, handler);
#endif
#ifdef SIGHUP
  if (signal (SIGHUP, SIG_IGN) != SIG_IGN)
    signal (SIGHUP, handler);
#endif
  if (signal (SIGSEGV, SIG_IGN) != SIG_IGN)
    signal (SIGSEGV, handler);
#ifdef SIGBUS
  if (signal (SIGBUS, SIG_IGN) != SIG_IGN)
    signal (SIGBUS, handler);
#endif

  /* Extract COMPILER_PATH and PATH into our prefix list.  */
  prefix_from_env ("COMPILER_PATH", &cpath);
  prefix_from_env ("PATH", &path);

  /* Try to discover a valid linker/nm/strip to use.  */

  /* Maybe we know the right file to use (if not cross).  */
  ld_file_name = 0;
#ifdef DEFAULT_LINKER
  if (access (DEFAULT_LINKER, X_OK) == 0)
    ld_file_name = DEFAULT_LINKER;
  if (ld_file_name == 0)
#endif
#ifdef REAL_LD_FILE_NAME
  ld_file_name = find_a_file (&path, REAL_LD_FILE_NAME);
  if (ld_file_name == 0)
#endif
  /* Search the (target-specific) compiler dirs for ld'.  */
  ld_file_name = find_a_file (&cpath, real_ld_suffix);
  /* Likewise for `collect-ld'.  */
  if (ld_file_name == 0)
    ld_file_name = find_a_file (&cpath, collect_ld_suffix);
  /* Search the compiler directories for `ld'.  We have protection against
     recursive calls in find_a_file.  */
  if (ld_file_name == 0)
    ld_file_name = find_a_file (&cpath, ld_suffix);
  /* Search the ordinary system bin directories
     for `ld' (if native linking) or `TARGET-ld' (if cross).  */
  if (ld_file_name == 0)
    ld_file_name = find_a_file (&path, full_ld_suffix);

#ifdef REAL_NM_FILE_NAME
  nm_file_name = find_a_file (&path, REAL_NM_FILE_NAME);
  if (nm_file_name == 0)
#endif
  nm_file_name = find_a_file (&cpath, gnm_suffix);
  if (nm_file_name == 0)
    nm_file_name = find_a_file (&path, full_gnm_suffix);
  if (nm_file_name == 0)
    nm_file_name = find_a_file (&cpath, nm_suffix);
  if (nm_file_name == 0)
    nm_file_name = find_a_file (&path, full_nm_suffix);

#ifdef LDD_SUFFIX
  ldd_file_name = find_a_file (&cpath, ldd_suffix);
  if (ldd_file_name == 0)
    ldd_file_name = find_a_file (&path, full_ldd_suffix);
#endif

#ifdef REAL_STRIP_FILE_NAME
  strip_file_name = find_a_file (&path, REAL_STRIP_FILE_NAME);
  if (strip_file_name == 0)
#endif
  strip_file_name = find_a_file (&cpath, gstrip_suffix);
  if (strip_file_name == 0)
    strip_file_name = find_a_file (&path, full_gstrip_suffix);
  if (strip_file_name == 0)
    strip_file_name = find_a_file (&cpath, strip_suffix);
  if (strip_file_name == 0)
    strip_file_name = find_a_file (&path, full_strip_suffix);

  /* Determine the full path name of the C compiler to use.  */
  c_file_name = getenv ("COLLECT_GCC");
  if (c_file_name == 0)
    {
#ifdef CROSS_DIRECTORY_STRUCTURE
      c_file_name = concat (target_machine, "-gcc", NULL);
#else
      c_file_name = "gcc";
#endif
    }

  p = find_a_file (&cpath, c_file_name);

  /* Here it should be safe to use the system search path since we should have
     already qualified the name of the compiler when it is needed.  */
  if (p == 0)
    p = find_a_file (&path, c_file_name);

  if (p)
    c_file_name = p;

  *ld1++ = *ld2++ = ld_file_name;

  /* Make temp file names.  */
  c_file = make_temp_file (".c");
  o_file = make_temp_file (".o");
#ifdef COLLECT_EXPORT_LIST
  export_file = make_temp_file (".x");
#endif
  ldout = make_temp_file (".ld");
  lderrout = make_temp_file (".le");
  *c_ptr++ = c_file_name;
  *c_ptr++ = "-x";
  *c_ptr++ = "c";
  *c_ptr++ = "-c";
  *c_ptr++ = "-o";
  *c_ptr++ = o_file;

#ifdef COLLECT_EXPORT_LIST
  /* Generate a list of directories from LIBPATH.  */
  prefix_from_env ("LIBPATH", &libpath_lib_dirs);
  /* Add to this list also two standard directories where
     AIX loader always searches for libraries.  */
  add_prefix (&libpath_lib_dirs, "/lib");
  add_prefix (&libpath_lib_dirs, "/usr/lib");
#endif

  /* Get any options that the upper GCC wants to pass to the sub-GCC.

     AIX support needs to know if -shared has been specified before
     parsing commandline arguments.  */

  p = getenv ("COLLECT_GCC_OPTIONS");
  while (p && *p)
    {
      const char *q = extract_string (&p);
      if (*q == '-' && (q[1] == 'm' || q[1] == 'f'))
        *c_ptr++ = xstrdup (q);
      if (strcmp (q, "-EL") == 0 || strcmp (q, "-EB") == 0)
        *c_ptr++ = xstrdup (q);
      if (strcmp (q, "-shared") == 0)
        shared_obj = 1;
      if (*q == '-' && q[1] == 'B')
        {
          *c_ptr++ = xstrdup (q);
          if (q[2] == 0)
            {
              q = extract_string (&p);
              *c_ptr++ = xstrdup (q);
            }
        }
    }
  obstack_free (&temporary_obstack, temporary_firstobj);
  *c_ptr++ = "-fno-profile-arcs";
  *c_ptr++ = "-fno-test-coverage";
  *c_ptr++ = "-fno-branch-probabilities";
  *c_ptr++ = "-fno-exceptions";
  *c_ptr++ = "-w";

  /* !!! When GCC calls collect2,
     it does not know whether it is calling collect2 or ld.
     So collect2 cannot meaningfully understand any options
     except those ld understands.
     If you propose to make GCC pass some other option,
     just imagine what will happen if ld is really ld!!!  */

  /* Parse arguments.  Remember output file spec, pass the rest to ld.  */
  /* After the first file, put in the c++ rt0.  */

  first_file = 1;
#ifdef HAVE_LD_DEMANGLE
  if (!demangle_flag && !no_demangle)
    demangle_flag = "--demangle";
  if (demangle_flag)
    *ld1++ = *ld2++ = demangle_flag;
#endif
  while ((arg = *++argv) != (char *) 0)
    {
      *ld1++ = *ld2++ = arg;

      if (arg[0] == '-')
        {
          switch (arg[1])
            {
#ifdef COLLECT_EXPORT_LIST
            /* We want to disable automatic exports on AIX when user
               explicitly puts an export list in command line */
            case 'b':
              if (arg[2] == 'E' || strncmp (&arg[2], "export", 6) == 0)
                export_flag = 1;
              else if (arg[2] == '6' && arg[3] == '4')
                aix64_flag = 1;
              else if (arg[2] == 'r' && arg[3] == 't' && arg[4] == 'l')
                aixrtl_flag = 1;
              break;
#endif

            case 'd':
              if (!strcmp (arg, "-debug"))
                {
                  /* Already parsed.  */
                  ld1--;
                  ld2--;
                }
              if (!strcmp (arg, "-dynamic-linker") && argv[1])
                {
                  ++argv;
                  *ld1++ = *ld2++ = *argv;
                }
              break;

            case 'l':
              if (first_file)
                {
                  /* place o_file BEFORE this argument! */
                  first_file = 0;
                  ld2--;
                  *ld2++ = o_file;
                  *ld2++ = arg;
                }
#ifdef COLLECT_EXPORT_LIST
              {
                /* Resolving full library name.  */
                const char *s = resolve_lib_name (arg+2);

                /* Saving a full library name.  */
                add_to_list (&libs, s);
              }
#endif
              break;

#ifdef COLLECT_EXPORT_LIST
            /* Saving directories where to search for libraries.  */
            case 'L':
              add_prefix (&cmdline_lib_dirs, arg+2);
              break;
#else
#if LINK_ELIMINATE_DUPLICATE_LDIRECTORIES
            case 'L':
              if (is_in_args (arg, (const char **) ld1_argv, ld1-1))
                --ld1;
              break;
#endif /* LINK_ELIMINATE_DUPLICATE_LDIRECTORIES */
#endif

            case 'o':
              if (arg[2] == '\0')
                output_file = *ld1++ = *ld2++ = *++argv;
              else if (1
#ifdef SWITCHES_NEED_SPACES
                       && ! strchr (SWITCHES_NEED_SPACES, arg[1])
#endif
                       )

                output_file = &arg[2];
              break;

            case 'r':
              if (arg[2] == '\0')
                rflag = 1;
              break;

            case 's':
              if (arg[2] == '\0' && do_collecting)
                {
                  /* We must strip after the nm run, otherwise C++ linking
                     will not work.  Thus we strip in the second ld run, or
                     else with strip if there is no second ld run.  */
                  strip_flag = 1;
                  ld1--;
                }
              break;

            case 'v':
              if (arg[2] == '\0')
                vflag = 1;
              break;

            case '-':
              if (strcmp (arg, "--no-demangle") == 0)
                {
                  demangle_flag = arg;
                  no_demangle = 1;
                  ld1--;
                  ld2--;
                }
              else if (strncmp (arg, "--demangle", 10) == 0)
                {
                  demangle_flag = arg;
                  no_demangle = 0;
#ifndef HAVE_LD_DEMANGLE
                  if (arg[10] == '=')
                    {
                      enum demangling_styles style
                        = cplus_demangle_name_to_style (arg+11);
                      if (style == unknown_demangling)
                        error ("unknown demangling style '%s'", arg+11);
                      else
                        current_demangling_style = style;
                    }
#endif
                  ld1--;
                  ld2--;
                }
              break;
            }
        }
      else if ((p = strrchr (arg, '.')) != (char *) 0
               && (strcmp (p, ".o") == 0 || strcmp (p, ".a") == 0
                   || strcmp (p, ".so") == 0 || strcmp (p, ".lo") == 0
                   || strcmp (p, ".obj") == 0))
        {
          if (first_file)
            {
              first_file = 0;
              if (p[1] == 'o')
                *ld2++ = o_file;
              else
                {
                  /* place o_file BEFORE this argument! */
                  ld2--;
                  *ld2++ = o_file;
                  *ld2++ = arg;
                }
            }
          if (p[1] == 'o' || p[1] == 'l')
            *object++ = arg;
#ifdef COLLECT_EXPORT_LIST
          /* libraries can be specified directly, i.e. without -l flag.  */
          else
            {
              /* Saving a full library name.  */
              add_to_list (&libs, arg);
            }
#endif
        }
    }

#ifdef COLLECT_EXPORT_LIST
  /* This is added only for debugging purposes.  */
  if (debug)
    {
      fprintf (stderr, "List of libraries:\n");
      dump_list (stderr, "\t", libs.first);
    }

  /* The AIX linker will discard static constructors in object files if
     nothing else in the file is referenced, so look at them first.  */
  {
      const char **export_object_lst = (const char **)object_lst;

      while (export_object_lst < object)
        scan_prog_file (*export_object_lst++, PASS_OBJ);
  }
  {
    struct id *list = libs.first;

    for (; list; list = list->next)
      scan_prog_file (list->name, PASS_FIRST);
  }

  if (exports.first)
    {
      char *buf = concat ("-bE:", export_file, NULL);

      *ld1++ = buf;
      *ld2++ = buf;

      exportf = fopen (export_file, "w");
      if (exportf == (FILE *) 0)
        fatal_perror ("fopen %s", export_file);
      write_aix_file (exportf, exports.first);
      if (fclose (exportf))
        fatal_perror ("fclose %s", export_file);
    }
#endif

  *c_ptr++ = c_file;
  *c_ptr = *ld1 = *object = (char *) 0;

  if (vflag)
    {
      notice ("collect2 version %s", version_string);
#ifdef TARGET_VERSION
      TARGET_VERSION;
#endif
      fprintf (stderr, "\n");
    }

  if (debug)
    {
      const char *ptr;
      fprintf (stderr, "ld_file_name        = %s\n",
               (ld_file_name ? ld_file_name : "not found"));
      fprintf (stderr, "c_file_name         = %s\n",
               (c_file_name ? c_file_name : "not found"));
      fprintf (stderr, "nm_file_name        = %s\n",
               (nm_file_name ? nm_file_name : "not found"));
#ifdef LDD_SUFFIX
      fprintf (stderr, "ldd_file_name       = %s\n",
               (ldd_file_name ? ldd_file_name : "not found"));
#endif
      fprintf (stderr, "strip_file_name     = %s\n",
               (strip_file_name ? strip_file_name : "not found"));
      fprintf (stderr, "c_file              = %s\n",
               (c_file ? c_file : "not found"));
      fprintf (stderr, "o_file              = %s\n",
               (o_file ? o_file : "not found"));

      ptr = getenv ("COLLECT_GCC_OPTIONS");
      if (ptr)
        fprintf (stderr, "COLLECT_GCC_OPTIONS = %s\n", ptr);

      ptr = getenv ("COLLECT_GCC");
      if (ptr)
        fprintf (stderr, "COLLECT_GCC         = %s\n", ptr);

      ptr = getenv ("COMPILER_PATH");
      if (ptr)
        fprintf (stderr, "COMPILER_PATH       = %s\n", ptr);

      ptr = getenv (LIBRARY_PATH_ENV);
      if (ptr)
        fprintf (stderr, "%-20s= %s\n", LIBRARY_PATH_ENV, ptr);

      fprintf (stderr, "\n");
    }

  /* Load the program, searching all libraries and attempting to provide
     undefined symbols from repository information.  */

  /* On AIX we do this later.  */
#ifndef COLLECT_EXPORT_LIST
  do_tlink (ld1_argv, object_lst);
#endif

  /* If -r or they will be run via some other method, do not build the
     constructor or destructor list, just return now.  */
  if (rflag
#ifndef COLLECT_EXPORT_LIST
      || ! do_collecting
#endif
      )
    {
#ifdef COLLECT_EXPORT_LIST
      /* Do the link we avoided above if we are exiting.  */
      do_tlink (ld1_argv, object_lst);

      /* But make sure we delete the export file we may have created.  */
      if (export_file != 0 && export_file[0])
        maybe_unlink (export_file);
#endif
      maybe_unlink (c_file);
      maybe_unlink (o_file);
      return 0;
    }

  /* Examine the namelist with nm and search it for static constructors
     and destructors to call.
     Write the constructor and destructor tables to a .s file and reload.  */

  /* On AIX we already scanned for global constructors/destructors.  */
#ifndef COLLECT_EXPORT_LIST
  scan_prog_file (output_file, PASS_FIRST);
#endif

#ifdef SCAN_LIBRARIES
  scan_libraries (output_file);
#endif

  if (debug)
    {
      notice ("%d constructor(s) found\n", constructors.number);
      notice ("%d destructor(s)  found\n", destructors.number);
      notice ("%d frame table(s) found\n", frame_tables.number);
    }

  if (constructors.number == 0 && destructors.number == 0
      && frame_tables.number == 0
#if defined (SCAN_LIBRARIES) || defined (COLLECT_EXPORT_LIST)
      /* If we will be running these functions ourselves, we want to emit
         stubs into the shared library so that we do not have to relink
         dependent programs when we add static objects.  */
      && ! shared_obj
#endif
      )
    {
#ifdef COLLECT_EXPORT_LIST
      /* Do tlink without additional code generation.  */
      do_tlink (ld1_argv, object_lst);
#endif
      /* Strip now if it was requested on the command line.  */
      if (strip_flag)
        {
          char **real_strip_argv = XCNEWVEC (char *, 3);
          const char ** strip_argv = CONST_CAST2 (const char **, char **,
                                                  real_strip_argv);

          strip_argv[0] = strip_file_name;
          strip_argv[1] = output_file;
          strip_argv[2] = (char *) 0;
          fork_execute ("strip", real_strip_argv);
        }

#ifdef COLLECT_EXPORT_LIST
      maybe_unlink (export_file);
#endif
      maybe_unlink (c_file);
      maybe_unlink (o_file);
      return 0;
    }

  /* Sort ctor and dtor lists by priority.  */
  sort_ids (&constructors);
  sort_ids (&destructors);

  maybe_unlink(output_file);
  outf = fopen (c_file, "w");
  if (outf == (FILE *) 0)
    fatal_perror ("fopen %s", c_file);

  write_c_file (outf, c_file);

  if (fclose (outf))
    fatal_perror ("fclose %s", c_file);

  /* Tell the linker that we have initializer and finalizer functions.  */
#ifdef LD_INIT_SWITCH
#ifdef COLLECT_EXPORT_LIST
  *ld2++ = concat (LD_INIT_SWITCH, ":", initname, ":", fininame, NULL);
#else
  *ld2++ = LD_INIT_SWITCH;
  *ld2++ = initname;
  *ld2++ = LD_FINI_SWITCH;
  *ld2++ = fininame;
#endif
#endif

#ifdef COLLECT_EXPORT_LIST
  if (shared_obj)
    {
      /* If we did not add export flag to link arguments before, add it to
         second link phase now.  No new exports should have been added.  */
      if (! exports.first)
        *ld2++ = concat ("-bE:", export_file, NULL);

#ifndef LD_INIT_SWITCH
      add_to_list (&exports, initname);
      add_to_list (&exports, fininame);
      add_to_list (&exports, "_GLOBAL__DI");
      add_to_list (&exports, "_GLOBAL__DD");
#endif
      exportf = fopen (export_file, "w");
      if (exportf == (FILE *) 0)
        fatal_perror ("fopen %s", export_file);
      write_aix_file (exportf, exports.first);
      if (fclose (exportf))
        fatal_perror ("fclose %s", export_file);
    }
#endif

  /* End of arguments to second link phase.  */
  *ld2 = (char*) 0;

  if (debug)
    {
      fprintf (stderr, "\n========== output_file = %s, c_file = %s\n",
               output_file, c_file);
      write_c_file (stderr, "stderr");
      fprintf (stderr, "========== end of c_file\n\n");
#ifdef COLLECT_EXPORT_LIST
      fprintf (stderr, "\n========== export_file = %s\n", export_file);
      write_aix_file (stderr, exports.first);
      fprintf (stderr, "========== end of export_file\n\n");
#endif
    }

  /* Assemble the constructor and destructor tables.
     Link the tables in with the rest of the program.  */

  fork_execute ("gcc",  c_argv);
#ifdef COLLECT_EXPORT_LIST
  /* On AIX we must call tlink because of possible templates resolution.  */
  do_tlink (ld2_argv, object_lst);
#else
  /* Otherwise, simply call ld because tlink is already done.  */
  fork_execute ("ld", ld2_argv);

  /* Let scan_prog_file do any final mods (OSF/rose needs this for
     constructors/destructors in shared libraries.  */
  scan_prog_file (output_file, PASS_SECOND);
#endif

  maybe_unlink (c_file);
  maybe_unlink (o_file);

#ifdef COLLECT_EXPORT_LIST
  maybe_unlink (export_file);
#endif

  return 0;
}

\f
/* Wait for a process to finish, and exit if a nonzero status is found.  */

int
collect_wait (const char *prog, struct pex_obj *pex)
{
  int status;

  if (!pex_get_status (pex, 1, &status))
    fatal_perror ("can't get program status");
  pex_free (pex);

  if (status)
    {
      if (WIFSIGNALED (status))
        {
          int sig = WTERMSIG (status);
          error ("%s terminated with signal %d [%s]%s",
                 prog, sig, strsignal(sig),
                 WCOREDUMP(status) ? ", core dumped" : "");
          collect_exit (FATAL_EXIT_CODE);
        }

      if (WIFEXITED (status))
        return WEXITSTATUS (status);
    }
  return 0;
}

static void
do_wait (const char *prog, struct pex_obj *pex)
{
  int ret = collect_wait (prog, pex);
  if (ret != 0)
    {
      error ("%s returned %d exit status", prog, ret);
      collect_exit (ret);
    }

  if (response_file)
    {
      unlink (response_file);
      response_file = NULL;
    }
}

\f
/* Execute a program, and wait for the reply.  */

struct pex_obj *
collect_execute (const char *prog, char **argv, const char *outname,
                 const char *errname)
{
  struct pex_obj *pex;
  const char *errmsg;
  int err;
  char *response_arg = NULL;
  char *response_argv[3] ATTRIBUTE_UNUSED;

  if (HAVE_GNU_LD && at_file_supplied && argv[0] != NULL)
    {
      /* If using @file arguments, create a temporary file and put the
         contents of argv into it.  Then change argv to an array corresponding
         to a single argument @FILE, where FILE is the temporary filename.  */

      char **current_argv = argv + 1;
      char *argv0 = argv[0];
      int status;
      FILE *f;

      /* Note: we assume argv contains at least one element; this is
         checked above.  */

      response_file = make_temp_file ("");

      f = fopen (response_file, "w");

      if (f == NULL)
        fatal ("could not open response file %s", response_file);

      status = writeargv (current_argv, f);

      if (status)
        fatal ("could not write to response file %s", response_file);

      status = fclose (f);

      if (EOF == status)
        fatal ("could not close response file %s", response_file);

      response_arg = concat ("@", response_file, NULL);
      response_argv[0] = argv0;
      response_argv[1] = response_arg;
      response_argv[2] = NULL;

      argv = response_argv;
    }

  if (vflag || debug)
    {
      char **p_argv;
      const char *str;

      if (argv[0])
        fprintf (stderr, "%s", argv[0]);
      else
        notice ("[cannot find %s]", prog);

      for (p_argv = &argv[1]; (str = *p_argv) != (char *) 0; p_argv++)
        fprintf (stderr, " %s", str);

      fprintf (stderr, "\n");
    }

  fflush (stdout);
  fflush (stderr);

  /* If we cannot find a program we need, complain error.  Do this here
     since we might not end up needing something that we could not find.  */

  if (argv[0] == 0)
    fatal ("cannot find '%s'", prog);

  pex = pex_init (0, "collect2", NULL);
  if (pex == NULL)
    fatal_perror ("pex_init failed");

  errmsg = pex_run (pex, PEX_LAST | PEX_SEARCH, argv[0], argv, outname,
                    errname, &err);
  if (errmsg != NULL)
    {
      if (err != 0)
        {
          errno = err;
          fatal_perror (errmsg);
        }
      else
        fatal (errmsg);
    }

  if (response_arg)
    free (response_arg);

  return pex;
}

static void
fork_execute (const char *prog, char **argv)
{
  struct pex_obj *pex;

  pex = collect_execute (prog, argv, NULL, NULL);
  do_wait (prog, pex);
}
\f
/* Unlink a file unless we are debugging.  */

static void
maybe_unlink (const char *file)
{
  if (!debug)
    unlink_if_ordinary (file);
  else
    notice ("[Leaving %s]\n", file);
}

\f
static long sequence_number = 0;

/* Add a name to a linked list.  */

static void
add_to_list (struct head *head_ptr, const char *name)
{
  struct id *newid
    = (struct id *) xcalloc (sizeof (struct id) + strlen (name), 1);
  struct id *p;
  strcpy (newid->name, name);

  if (head_ptr->first)
    head_ptr->last->next = newid;
  else
    head_ptr->first = newid;

  /* Check for duplicate symbols.  */
  for (p = head_ptr->first;
       strcmp (name, p->name) != 0;
       p = p->next)
    ;
  if (p != newid)
    {
      head_ptr->last->next = 0;
      free (newid);
      return;
    }

  newid->sequence = ++sequence_number;
  head_ptr->last = newid;
  head_ptr->number++;
}

/* Grab the init priority number from an init function name that
   looks like "_GLOBAL_.I.12345.foo".  */

static int
extract_init_priority (const char *name)
{
  int pos = 0, pri;

  while (name[pos] == '_')
    ++pos;
  pos += 10; /* strlen ("GLOBAL__X_") */

  /* Extract init_p number from ctor/dtor name.  */
  pri = atoi (name + pos);
  return pri ? pri : DEFAULT_INIT_PRIORITY;
}

/* Insertion sort the ids from ctor/dtor list HEAD_PTR in descending order.
   ctors will be run from right to left, dtors from left to right.  */

static void
sort_ids (struct head *head_ptr)
{
  /* id holds the current element to insert.  id_next holds the next
     element to insert.  id_ptr iterates through the already sorted elements
     looking for the place to insert id.  */
  struct id *id, *id_next, **id_ptr;

  id = head_ptr->first;

  /* We don't have any sorted elements yet.  */
  head_ptr->first = NULL;

  for (; id; id = id_next)
    {
      id_next = id->next;
      id->sequence = extract_init_priority (id->name);

      for (id_ptr = &(head_ptr->first); ; id_ptr = &((*id_ptr)->next))
        if (*id_ptr == NULL
            /* If the sequence numbers are the same, we put the id from the
               file later on the command line later in the list.  */
            || id->sequence > (*id_ptr)->sequence
            /* Hack: do lexical compare, too.
            || (id->sequence == (*id_ptr)->sequence
                && strcmp (id->name, (*id_ptr)->name) > 0) */
            )
          {
            id->next = *id_ptr;
            *id_ptr = id;
            break;
          }
    }

  /* Now set the sequence numbers properly so write_c_file works.  */
  for (id = head_ptr->first; id; id = id->next)
    id->sequence = ++sequence_number;
}

/* Write: `prefix', the names on list LIST, `suffix'.  */

static void
write_list (FILE *stream, const char *prefix, struct id *list)
{
  while (list)
    {
      fprintf (stream, "%sx%d,\n", prefix, list->sequence);
      list = list->next;
    }
}

#if LINK_ELIMINATE_DUPLICATE_LDIRECTORIES
/* Given a STRING, return nonzero if it occurs in the list in range
   [ARGS_BEGIN,ARGS_END).  */

static int
is_in_args (const char *string, const char **args_begin,
            const char **args_end)
{
  const char **args_pointer;
  for (args_pointer = args_begin; args_pointer != args_end; ++args_pointer)
    if (strcmp (string, *args_pointer) == 0)
      return 1;
  return 0;
}
#endif /* LINK_ELIMINATE_DUPLICATE_LDIRECTORIES */

#ifdef COLLECT_EXPORT_LIST
/* This function is really used only on AIX, but may be useful.  */
#if 0
static int
is_in_list (const char *prefix, struct id *list)
{
  while (list)
    {
      if (!strcmp (prefix, list->name)) return 1;
      list = list->next;
    }
    return 0;
}
#endif
#endif /* COLLECT_EXPORT_LIST */

/* Added for debugging purpose.  */
#ifdef COLLECT_EXPORT_LIST
static void
dump_list (FILE *stream, const char *prefix, struct id *list)
{
  while (list)
    {
      fprintf (stream, "%s%s,\n", prefix, list->name);
      list = list->next;
    }
}
#endif

#if 0
static void
dump_prefix_list (FILE *stream, const char *prefix, struct prefix_list *list)
{
  while (list)
    {
      fprintf (stream, "%s%s,\n", prefix, list->prefix);
      list = list->next;
    }
}
#endif

static void
write_list_with_asm (FILE *stream, const char *prefix, struct id *list)
{
  while (list)
    {
      fprintf (stream, "%sx%d __asm__ (\"%s\");\n",
               prefix, list->sequence, list->name);
      list = list->next;
    }
}

/* Write out the constructor and destructor tables statically (for a shared
   object), along with the functions to execute them.  */

static void
write_c_file_stat (FILE *stream, const char *name ATTRIBUTE_UNUSED)
{
  const char *p, *q;
  char *prefix, *r;
  int frames = (frame_tables.number > 0);

  /* Figure out name of output_file, stripping off .so version.  */
  p = strrchr (output_file, '/');
  if (p == 0)
    p = output_file;
  else
    p++;
  q = p;
  while (q)
    {
      q = strchr (q,'.');
      if (q == 0)
        {
          q = p + strlen (p);
          break;
        }
      else
        {
          if (strncmp (q, SHLIB_SUFFIX, strlen (SHLIB_SUFFIX)) == 0)
            {
              q += strlen (SHLIB_SUFFIX);
              break;
            }
          else
            q++;
        }
    }
  /* q points to null at end of the string (or . of the .so version) */
  prefix = XNEWVEC (char, q - p + 1);
  strncpy (prefix, p, q - p);
  prefix[q - p] = 0;
  for (r = prefix; *r; r++)
    if (!ISALNUM ((unsigned char)*r))
      *r = '_';
  if (debug)
    notice ("\nwrite_c_file - output name is %s, prefix is %s\n",
            output_file, prefix);

  initname = concat ("_GLOBAL__FI_", prefix, NULL);
  fininame = concat ("_GLOBAL__FD_", prefix, NULL);

  free (prefix);

  /* Write the tables as C code.  */

  fprintf (stream, "static int count;\n");
  fprintf (stream, "typedef void entry_pt();\n");
  write_list_with_asm (stream, "extern entry_pt ", constructors.first);

  if (frames)
    {
      write_list_with_asm (stream, "extern void *", frame_tables.first);

      fprintf (stream, "\tstatic void *frame_table[] = {\n");
      write_list (stream, "\t\t&", frame_tables.first);
      fprintf (stream, "\t0\n};\n");

      /* This must match what's in frame.h.  */
      fprintf (stream, "struct object {\n");
      fprintf (stream, "  void *pc_begin;\n");
      fprintf (stream, "  void *pc_end;\n");
      fprintf (stream, "  void *fde_begin;\n");
      fprintf (stream, "  void *fde_array;\n");
      fprintf (stream, "  __SIZE_TYPE__ count;\n");
      fprintf (stream, "  struct object *next;\n");
      fprintf (stream, "};\n");

      fprintf (stream, "extern void __register_frame_info_table (void *, struct object *);\n");
      fprintf (stream, "extern void *__deregister_frame_info (void *);\n");

      fprintf (stream, "static void reg_frame () {\n");
      fprintf (stream, "\tstatic struct object ob;\n");
      fprintf (stream, "\t__register_frame_info_table (frame_table, &ob);\n");
      fprintf (stream, "\t}\n");

      fprintf (stream, "static void dereg_frame () {\n");
      fprintf (stream, "\t__deregister_frame_info (frame_table);\n");
      fprintf (stream, "\t}\n");
    }

  fprintf (stream, "void %s() {\n", initname);
  if (constructors.number > 0 || frames)
    {
      fprintf (stream, "\tstatic entry_pt *ctors[] = {\n");
      write_list (stream, "\t\t", constructors.first);
      if (frames)
        fprintf (stream, "\treg_frame,\n");
      fprintf (stream, "\t};\n");
      fprintf (stream, "\tentry_pt **p;\n");
      fprintf (stream, "\tif (count++ != 0) return;\n");
      fprintf (stream, "\tp = ctors + %d;\n", constructors.number + frames);
      fprintf (stream, "\twhile (p > ctors) (*--p)();\n");
    }
  else
    fprintf (stream, "\t++count;\n");
  fprintf (stream, "}\n");
  write_list_with_asm (stream, "extern entry_pt ", destructors.first);
  fprintf (stream, "void %s() {\n", fininame);
  if (destructors.number > 0 || frames)
    {
      fprintf (stream, "\tstatic entry_pt *dtors[] = {\n");
      write_list (stream, "\t\t", destructors.first);
      if (frames)
        fprintf (stream, "\tdereg_frame,\n");
      fprintf (stream, "\t};\n");
      fprintf (stream, "\tentry_pt **p;\n");
      fprintf (stream, "\tif (--count != 0) return;\n");
      fprintf (stream, "\tp = dtors;\n");
      fprintf (stream, "\twhile (p < dtors + %d) (*p++)();\n",
               destructors.number + frames);
    }
  fprintf (stream, "}\n");

  if (shared_obj)
    {
      COLLECT_SHARED_INIT_FUNC(stream, initname);
      COLLECT_SHARED_FINI_FUNC(stream, fininame);
    }
}

/* Write the constructor/destructor tables.  */

#ifndef LD_INIT_SWITCH
static void
write_c_file_glob (FILE *stream, const char *name ATTRIBUTE_UNUSED)
{
  /* Write the tables as C code.  */

  int frames = (frame_tables.number > 0);

  fprintf (stream, "typedef void entry_pt();\n\n");

  write_list_with_asm (stream, "extern entry_pt ", constructors.first);

  if (frames)
    {
      write_list_with_asm (stream, "extern void *", frame_tables.first);

      fprintf (stream, "\tstatic void *frame_table[] = {\n");
      write_list (stream, "\t\t&", frame_tables.first);
      fprintf (stream, "\t0\n};\n");

      /* This must match what's in frame.h.  */
      fprintf (stream, "struct object {\n");
      fprintf (stream, "  void *pc_begin;\n");
      fprintf (stream, "  void *pc_end;\n");
      fprintf (stream, "  void *fde_begin;\n");
      fprintf (stream, "  void *fde_array;\n");
      fprintf (stream, "  __SIZE_TYPE__ count;\n");
      fprintf (stream, "  struct object *next;\n");
      fprintf (stream, "};\n");

      fprintf (stream, "extern void __register_frame_info_table (void *, struct object *);\n");
      fprintf (stream, "extern void *__deregister_frame_info (void *);\n");

      fprintf (stream, "static void reg_frame () {\n");
      fprintf (stream, "\tstatic struct object ob;\n");
      fprintf (stream, "\t__register_frame_info_table (frame_table, &ob);\n");
      fprintf (stream, "\t}\n");

      fprintf (stream, "static void dereg_frame () {\n");
      fprintf (stream, "\t__deregister_frame_info (frame_table);\n");
      fprintf (stream, "\t}\n");
    }

  fprintf (stream, "\nentry_pt * __CTOR_LIST__[] = {\n");
  fprintf (stream, "\t(entry_pt *) %d,\n", constructors.number + frames);
  write_list (stream, "\t", constructors.first);
  if (frames)
    fprintf (stream, "\treg_frame,\n");
  fprintf (stream, "\t0\n};\n\n");

  write_list_with_asm (stream, "extern entry_pt ", destructors.first);

  fprintf (stream, "\nentry_pt * __DTOR_LIST__[] = {\n");
  fprintf (stream, "\t(entry_pt *) %d,\n", destructors.number + frames);
  write_list (stream, "\t", destructors.first);
  if (frames)
    fprintf (stream, "\tdereg_frame,\n");
  fprintf (stream, "\t0\n};\n\n");

  fprintf (stream, "extern entry_pt %s;\n", NAME__MAIN);
  fprintf (stream, "entry_pt *__main_reference = %s;\n\n", NAME__MAIN);
}
#endif /* ! LD_INIT_SWITCH */

static void
write_c_file (FILE *stream, const char *name)
{
#ifndef LD_INIT_SWITCH
  if (! shared_obj)
    write_c_file_glob (stream, name);
  else
#endif
    write_c_file_stat (stream, name);
}

#ifdef COLLECT_EXPORT_LIST
static void
write_aix_file (FILE *stream, struct id *list)
{
  for (; list; list = list->next)
    {
      fputs (list->name, stream);
      putc ('\n', stream);
    }
}
#endif
\f
#ifdef OBJECT_FORMAT_NONE

/* Generic version to scan the name list of the loaded program for
   the symbols g++ uses for static constructors and destructors.

   The constructor table begins at __CTOR_LIST__ and contains a count
   of the number of pointers (or -1 if the constructors are built in a
   separate section by the linker), followed by the pointers to the
   constructor functions, terminated with a null pointer.  The
   destructor table has the same format, and begins at __DTOR_LIST__.  */

static void
scan_prog_file (const char *prog_name, enum pass which_pass)
{
  void (*int_handler) (int);
#ifdef SIGQUIT
  void (*quit_handler) (int);
#endif
  char *real_nm_argv[4];
  const char **nm_argv = CONST_CAST2 (const char **, char**, real_nm_argv);
  int argc = 0;
  struct pex_obj *pex;
  const char *errmsg;
  int err;
  char *p, buf[1024];
  FILE *inf;

  if (which_pass == PASS_SECOND)
    return;

  /* If we do not have an `nm', complain.  */
  if (nm_file_name == 0)
    fatal ("cannot find 'nm'");

  nm_argv[argc++] = nm_file_name;
  if (NM_FLAGS[0] != '\0')
    nm_argv[argc++] = NM_FLAGS;

  nm_argv[argc++] = prog_name;
  nm_argv[argc++] = (char *) 0;

  /* Trace if needed.  */
  if (vflag)
    {
      const char **p_argv;
      const char *str;

      for (p_argv = &nm_argv[0]; (str = *p_argv) != (char *) 0; p_argv++)
        fprintf (stderr, " %s", str);

      fprintf (stderr, "\n");
    }

  fflush (stdout);
  fflush (stderr);

  pex = pex_init (PEX_USE_PIPES, "collect2", NULL);
  if (pex == NULL)
    fatal_perror ("pex_init failed");

  errmsg = pex_run (pex, 0, nm_file_name, real_nm_argv, NULL, NULL, &err);
  if (errmsg != NULL)
    {
      if (err != 0)
        {
          errno = err;
          fatal_perror (errmsg);
        }
      else
        fatal (errmsg);
    }

  int_handler  = (void (*) (int)) signal (SIGINT,  SIG_IGN);
#ifdef SIGQUIT
  quit_handler = (void (*) (int)) signal (SIGQUIT, SIG_IGN);
#endif

  inf = pex_read_output (pex, 0);
  if (inf == NULL)
    fatal_perror ("can't open nm output");

  if (debug)
    fprintf (stderr, "\nnm output with constructors/destructors.\n");

  /* Read each line of nm output.  */
  while (fgets (buf, sizeof buf, inf) != (char *) 0)
    {
      int ch, ch2;
      char *name, *end;

      /* If it contains a constructor or destructor name, add the name
         to the appropriate list.  */

      for (p = buf; (ch = *p) != '\0' && ch != '\n' && ch != '_'; p++)
        if (ch == ' ' && p[1] == 'U' && p[2] == ' ')
          break;

      if (ch != '_')
        continue;

      name = p;
      /* Find the end of the symbol name.
         Do not include `|', because Encore nm can tack that on the end.  */
      for (end = p; (ch2 = *end) != '\0' && !ISSPACE (ch2) && ch2 != '|';
           end++)
        continue;


      *end = '\0';
      switch (is_ctor_dtor (name))
        {
        case SYM_CTOR:
          if (which_pass != PASS_LIB)
            add_to_list (&constructors, name);
          break;

        case SYM_DTOR:
          if (which_pass != PASS_LIB)
            add_to_list (&destructors, name);
          break;

        case SYM_INIT:
          if (which_pass != PASS_LIB)
            fatal ("init function found in object %s", prog_name);
#ifndef LD_INIT_SWITCH
          add_to_list (&constructors, name);
#endif
          break;

        case SYM_FINI:
          if (which_pass != PASS_LIB)
            fatal ("fini function found in object %s", prog_name);
#ifndef LD_FINI_SWITCH
          add_to_list (&destructors, name);
#endif
          break;

        case SYM_DWEH:
          if (which_pass != PASS_LIB)
            add_to_list (&frame_tables, name);
          break;

        default:                /* not a constructor or destructor */
          continue;
        }

      if (debug)
        fprintf (stderr, "\t%s\n", buf);
    }

  if (debug)
    fprintf (stderr, "\n");

  do_wait (nm_file_name, pex);

  signal (SIGINT,  int_handler);
#ifdef SIGQUIT
  signal (SIGQUIT, quit_handler);
#endif
}

#ifdef LDD_SUFFIX

/* Use the List Dynamic Dependencies program to find shared libraries that
   the output file depends upon and their initialization/finalization
   routines, if any.  */

static void
scan_libraries (const char *prog_name)
{
  static struct head libraries;         /* list of shared libraries found */
  struct id *list;
  void (*int_handler) (int);
#ifdef SIGQUIT
  void (*quit_handler) (int);
#endif
  char *real_ldd_argv[4];
  const char **ldd_argv = (const char **) real_ldd_argv;
  int argc = 0;
  struct pex_obj *pex;
  const char *errmsg;
  int err;
  char buf[1024];
  FILE *inf;

  /* If we do not have an `ldd', complain.  */
  if (ldd_file_name == 0)
    {
      error ("cannot find 'ldd'");
      return;
    }

  ldd_argv[argc++] = ldd_file_name;
  ldd_argv[argc++] = prog_name;
  ldd_argv[argc++] = (char *) 0;

  /* Trace if needed.  */
  if (vflag)
    {
      const char **p_argv;
      const char *str;

      for (p_argv = &ldd_argv[0]; (str = *p_argv) != (char *) 0; p_argv++)
        fprintf (stderr, " %s", str);

      fprintf (stderr, "\n");
    }

  fflush (stdout);
  fflush (stderr);

  pex = pex_init (PEX_USE_PIPES, "collect2", NULL);
  if (pex == NULL)
    fatal_perror ("pex_init failed");

  errmsg = pex_run (pex, 0, ldd_file_name, real_ldd_argv, NULL, NULL, &err);
  if (errmsg != NULL)
    {
      if (err != 0)
        {
          errno = err;
          fatal_perror (errmsg);
        }
      else
        fatal (errmsg);
    }

  int_handler  = (void (*) (int)) signal (SIGINT,  SIG_IGN);
#ifdef SIGQUIT
  quit_handler = (void (*) (int)) signal (SIGQUIT, SIG_IGN);
#endif

  inf = pex_read_output (pex, 0);
  if (inf == NULL)
    fatal_perror ("can't open ldd output");

  if (debug)
    notice ("\nldd output with constructors/destructors.\n");

  /* Read each line of ldd output.  */
  while (fgets (buf, sizeof buf, inf) != (char *) 0)
    {
      int ch2;
      char *name, *end, *p = buf;

      /* Extract names of libraries and add to list.  */
      PARSE_LDD_OUTPUT (p);
      if (p == 0)
        continue;

      name = p;
      if (strncmp (name, "not found", sizeof ("not found") - 1) == 0)
        fatal ("dynamic dependency %s not found", buf);

      /* Find the end of the symbol name.  */
      for (end = p;
           (ch2 = *end) != '\0' && ch2 != '\n' && !ISSPACE (ch2) && ch2 != '|';
           end++)
        continue;
      *end = '\0';

      if (access (name, R_OK) == 0)
        add_to_list (&libraries, name);
      else
        fatal ("unable to open dynamic dependency '%s'", buf);

      if (debug)
        fprintf (stderr, "\t%s\n", buf);
    }
  if (debug)
    fprintf (stderr, "\n");

  do_wait (ldd_file_name, pex);

  signal (SIGINT,  int_handler);
#ifdef SIGQUIT
  signal (SIGQUIT, quit_handler);
#endif

  /* Now iterate through the library list adding their symbols to
     the list.  */
  for (list = libraries.first; list; list = list->next)
    scan_prog_file (list->name, PASS_LIB);
}

#endif /* LDD_SUFFIX */

#endif /* OBJECT_FORMAT_NONE */

\f
/*
 * COFF specific stuff.
 */

#ifdef OBJECT_FORMAT_COFF

#if defined (EXTENDED_COFF)

#   define GCC_SYMBOLS(X)       (SYMHEADER(X).isymMax + SYMHEADER(X).iextMax)
#   define GCC_SYMENT           SYMR
#   define GCC_OK_SYMBOL(X)     ((X).st == stProc || (X).st == stGlobal)
#   define GCC_SYMINC(X)        (1)
#   define GCC_SYMZERO(X)       (SYMHEADER(X).isymMax)
#   define GCC_CHECK_HDR(X)     (PSYMTAB(X) != 0)

#else

#   define GCC_SYMBOLS(X)       (HEADER(ldptr).f_nsyms)
#   define GCC_SYMENT           SYMENT
#   if defined (C_WEAKEXT)
#     define GCC_OK_SYMBOL(X) \
       (((X).n_sclass == C_EXT || (X).n_sclass == C_WEAKEXT) && \
        ((X).n_scnum > N_UNDEF) && \
        (aix64_flag \
         || (((X).n_type & N_TMASK) == (DT_NON << N_BTSHFT) \
             || ((X).n_type & N_TMASK) == (DT_FCN << N_BTSHFT))))
#     define GCC_UNDEF_SYMBOL(X) \
       (((X).n_sclass == C_EXT || (X).n_sclass == C_WEAKEXT) && \
        ((X).n_scnum == N_UNDEF))
#   else
#     define GCC_OK_SYMBOL(X) \
       (((X).n_sclass == C_EXT) && \
        ((X).n_scnum > N_UNDEF) && \
        (aix64_flag \
         || (((X).n_type & N_TMASK) == (DT_NON << N_BTSHFT) \
             || ((X).n_type & N_TMASK) == (DT_FCN << N_BTSHFT))))
#     define GCC_UNDEF_SYMBOL(X) \
       (((X).n_sclass == C_EXT) && ((X).n_scnum == N_UNDEF))
#   endif
#   define GCC_SYMINC(X)        ((X).n_numaux+1)
#   define GCC_SYMZERO(X)       0

/* 0757 = U803XTOCMAGIC (AIX 4.3) and 0767 = U64_TOCMAGIC (AIX V5) */
#ifdef _AIX51
#   define GCC_CHECK_HDR(X) \
     ((HEADER (X).f_magic == U802TOCMAGIC && ! aix64_flag) \
      || (HEADER (X).f_magic == 0767 && aix64_flag))
#else
#   define GCC_CHECK_HDR(X) \
     ((HEADER (X).f_magic == U802TOCMAGIC && ! aix64_flag) \
      || (HEADER (X).f_magic == 0757 && aix64_flag))
#endif

#endif

#ifdef COLLECT_EXPORT_LIST
/* Array of standard AIX libraries which should not
   be scanned for ctors/dtors.  */
static const char *const aix_std_libs[] = {
  "/unix",
  "/lib/libc.a",
  "/lib/libm.a",
  "/lib/libc_r.a",
  "/lib/libm_r.a",
  "/usr/lib/libc.a",
  "/usr/lib/libm.a",
  "/usr/lib/libc_r.a",
  "/usr/lib/libm_r.a",
  "/usr/lib/threads/libc.a",
  "/usr/ccs/lib/libc.a",
  "/usr/ccs/lib/libm.a",
  "/usr/ccs/lib/libc_r.a",
  "/usr/ccs/lib/libm_r.a",
  NULL
};

/* This function checks the filename and returns 1
   if this name matches the location of a standard AIX library.  */
static int ignore_library (const char *);
static int
ignore_library (const char *name)
{
  const char *const *p;

  for (p = &aix_std_libs[0]; *p != NULL; ++p)
    if (strcmp (name, *p) == 0)
      return 1;
  return 0;
}
#endif /* COLLECT_EXPORT_LIST */

#if defined (HAVE_DECL_LDGETNAME) && !HAVE_DECL_LDGETNAME
extern char *ldgetname (LDFILE *, GCC_SYMENT *);
#endif

/* COFF version to scan the name list of the loaded program for
   the symbols g++ uses for static constructors and destructors.

   The constructor table begins at __CTOR_LIST__ and contains a count
   of the number of pointers (or -1 if the constructors are built in a
   separate section by the linker), followed by the pointers to the
   constructor functions, terminated with a null pointer.  The
   destructor table has the same format, and begins at __DTOR_LIST__.  */

static void
scan_prog_file (const char *prog_name, enum pass which_pass)
{
  LDFILE *ldptr = NULL;
  int sym_index, sym_count;
  int is_shared = 0;

  if (which_pass != PASS_FIRST && which_pass != PASS_OBJ)
    return;

#ifdef COLLECT_EXPORT_LIST
  /* We do not need scanning for some standard C libraries.  */
  if (which_pass == PASS_FIRST && ignore_library (prog_name))
    return;

  /* On AIX we have a loop, because there is not much difference
     between an object and an archive. This trick allows us to
     eliminate scan_libraries() function.  */
  do
    {
#endif
      /* Some platforms (e.g. OSF4) declare ldopen as taking a
         non-const char * filename parameter, even though it will not
         modify that string.  So we must cast away const-ness here,
         using CONST_CAST to prevent complaints from -Wcast-qual.  */
      if ((ldptr = ldopen (CONST_CAST (char *, prog_name), ldptr)) != NULL)
        {
          if (! MY_ISCOFF (HEADER (ldptr).f_magic))
            fatal ("%s: not a COFF file", prog_name);

          if (GCC_CHECK_HDR (ldptr))
            {
              sym_count = GCC_SYMBOLS (ldptr);
              sym_index = GCC_SYMZERO (ldptr);

#ifdef COLLECT_EXPORT_LIST
              /* Is current archive member a shared object?  */
              is_shared = HEADER (ldptr).f_flags & F_SHROBJ;
#endif

              while (sym_index < sym_count)
                {
                  GCC_SYMENT symbol;

                  if (ldtbread (ldptr, sym_index, &symbol) <= 0)
                    break;
                  sym_index += GCC_SYMINC (symbol);

                  if (GCC_OK_SYMBOL (symbol))
                    {
                      char *name;

                      if ((name = ldgetname (ldptr, &symbol)) == NULL)
                        continue;               /* Should never happen.  */

#ifdef XCOFF_DEBUGGING_INFO
                      /* All AIX function names have a duplicate entry
                         beginning with a dot.  */
                      if (*name == '.')
                        ++name;
#endif

                      switch (is_ctor_dtor (name))
                        {
                        case SYM_CTOR:
                          if (! is_shared)
                            add_to_list (&constructors, name);
#if defined (COLLECT_EXPORT_LIST) && !defined (LD_INIT_SWITCH)
                          if (which_pass == PASS_OBJ)
                            add_to_list (&exports, name);
#endif
                          break;

                        case SYM_DTOR:
                          if (! is_shared)
                            add_to_list (&destructors, name);
#if defined (COLLECT_EXPORT_LIST) && !defined (LD_INIT_SWITCH)
                          if (which_pass == PASS_OBJ)
                            add_to_list (&exports, name);
#endif
                          break;

#ifdef COLLECT_EXPORT_LIST
                        case SYM_INIT:
#ifndef LD_INIT_SWITCH
                          if (is_shared)
                            add_to_list (&constructors, name);
#endif
                          break;

                        case SYM_FINI:
#ifndef LD_INIT_SWITCH
                          if (is_shared)
                            add_to_list (&destructors, name);
#endif
                          break;
#endif

                        case SYM_DWEH:
                          if (! is_shared)
                            add_to_list (&frame_tables, name);
#if defined (COLLECT_EXPORT_LIST) && !defined (LD_INIT_SWITCH)
                          if (which_pass == PASS_OBJ)
                            add_to_list (&exports, name);
#endif
                          break;

                        default:        /* not a constructor or destructor */
#ifdef COLLECT_EXPORT_LIST
                          /* Explicitly export all global symbols when
                             building a shared object on AIX, but do not
                             re-export symbols from another shared object
                             and do not export symbols if the user
                             provides an explicit export list.  */
                          if (shared_obj && !is_shared
                              && which_pass == PASS_OBJ && !export_flag)
                            add_to_list (&exports, name);
#endif
                          continue;
                        }

                      if (debug)
#if !defined(EXTENDED_COFF)
                        fprintf (stderr, "\tsec=%d class=%d type=%s%o %s\n",
                                 symbol.n_scnum, symbol.n_sclass,
                                 (symbol.n_type ? "0" : ""), symbol.n_type,
                                 name);
#else
                        fprintf (stderr,
                                 "\tiss = %5d, value = %5ld, index = %5d, name = %s\n",
                                 symbol.iss, (long) symbol.value, symbol.index, name);
#endif
                    }
                }
            }
#ifdef COLLECT_EXPORT_LIST
          else
            {
              /* If archive contains both 32-bit and 64-bit objects,
                 we want to skip objects in other mode so mismatch normal.  */
              if (debug)
                fprintf (stderr, "%s : magic=%o aix64=%d mismatch\n",
                         prog_name, HEADER (ldptr).f_magic, aix64_flag);
            }
#endif
        }
      else
        {
          fatal ("%s: cannot open as COFF file", prog_name);
        }
#ifdef COLLECT_EXPORT_LIST
      /* On AIX loop continues while there are more members in archive.  */
    }
  while (ldclose (ldptr) == FAILURE);
#else
  /* Otherwise we simply close ldptr.  */
  (void) ldclose(ldptr);
#endif
}
#endif /* OBJECT_FORMAT_COFF */

#ifdef COLLECT_EXPORT_LIST
/* Given a library name without "lib" prefix, this function
   returns a full library name including a path.  */
static char *
resolve_lib_name (const char *name)
{
  char *lib_buf;
  int i, j, l = 0;
  /* Library extensions for AIX dynamic linking.  */
  const char * const libexts[2] = {"a", "so"};

  for (i = 0; libpaths[i]; i++)
    if (libpaths[i]->max_len > l)
      l = libpaths[i]->max_len;

  lib_buf = XNEWVEC (char, l + strlen(name) + 10);

  for (i = 0; libpaths[i]; i++)
    {
      struct prefix_list *list = libpaths[i]->plist;
      for (; list; list = list->next)
        {
          /* The following lines are needed because path_prefix list
             may contain directories both with trailing '/' and
             without it.  */
          const char *p = "";
          if (list->prefix[strlen(list->prefix)-1] != '/')
            p = "/";
          for (j = 0; j < 2; j++)
            {
              sprintf (lib_buf, "%s%slib%s.%s",
                       list->prefix, p, name,
                       libexts[(j + aixrtl_flag) % 2]);
              if (debug) fprintf (stderr, "searching for: %s\n", lib_buf);
              if (file_exists (lib_buf))
                {
                  if (debug) fprintf (stderr, "found: %s\n", lib_buf);
                  return (lib_buf);
                }
            }
        }
    }
  if (debug)
    fprintf (stderr, "not found\n");
  else
    fatal ("library lib%s not found", name);
  return (NULL);
}
#endif /* COLLECT_EXPORT_LIST */