collect2.c

早期freebsd实现

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

/* Write the constructor/destructor tables. */

static void
write_c_file (stream, name)
     FILE *stream;
     char *name;
{
  /* Write the tables as C code  */

  fprintf (stream, "typedef void entry_pt();\n\n");
    
  write_list_with_asm (stream, "extern entry_pt ", constructors.first);
    
  fprintf (stream, "\nentry_pt * __CTOR_LIST__[] = {\n");
  fprintf (stream, "\t(entry_pt *) %d,\n", constructors.number);
  write_list (stream, "\t", constructors.first);
  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);
  write_list (stream, "\t", destructors.first);
  fprintf (stream, "\t0\n};\n\n");

  fprintf (stream, "extern entry_pt __main;\n");
  fprintf (stream, "entry_pt *__main_reference = __main;\n\n");
}


#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 (prog_name, which_pass)
     char *prog_name;
     enum pass which_pass;
{
  void (*int_handler) ();
  void (*quit_handler) ();
  char *nm_argv[4];
  int pid;
  int argc = 0;
  int pipe_fd[2];
  char *p, buf[1024];
  FILE *inf;

  if (which_pass != PASS_FIRST)
    return;

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

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

  if (pipe (pipe_fd) < 0)
    fatal_perror ("pipe");

  inf = fdopen (pipe_fd[0], "r");
  if (inf == (FILE *)0)
    fatal_perror ("fdopen");

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

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

      fprintf (stderr, "\n");
    }

  fflush (stdout);
  fflush (stderr);

  /* Spawn child nm on pipe */
  pid = vfork ();
  if (pid == -1)
    fatal_perror ("vfork");

  if (pid == 0)			/* child context */
    {
      /* setup stdout */
      if (dup2 (pipe_fd[1], 1) < 0)
	fatal_perror ("dup2 (%d, 1)", pipe_fd[1]);

      if (close (pipe_fd[0]) < 0)
	fatal_perror ("close (%d)", pipe_fd[0]);

      if (close (pipe_fd[1]) < 0)
	fatal_perror ("close (%d)", pipe_fd[1]);

      execv (nm_file_name, nm_argv);
      fatal_perror ("executing %s", nm_file_name);
    }

  /* Parent context from here on.  */
  int_handler  = (void (*) ())signal (SIGINT,  SIG_IGN);
  quit_handler = (void (*) ())signal (SIGQUIT, SIG_IGN);

  if (close (pipe_fd[1]) < 0)
    fatal_perror ("close (%d)", pipe_fd[1]);

  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 == '\0' || ch == '\n')
	continue;
  
      name = p;
      /* Find the end of the symbol name.
	 Don't 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 1:
	  add_to_list (&constructors, name);
	  break;

	case 2:
	  add_to_list (&destructors, name);
	  break;

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

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

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

  if (fclose (inf) != 0)
    fatal_perror ("fclose of pipe");

  do_wait (nm_file_name);

  signal (SIGINT,  int_handler);
  signal (SIGQUIT, quit_handler);
}

#endif /* OBJECT_FORMAT_NONE */


/*
 * 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).sc == scText)
#   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
#   define GCC_OK_SYMBOL(X) \
     (((X).n_sclass == C_EXT) && \
        (((X).n_type & N_TMASK) == (DT_NON << N_BTSHFT) || \
         ((X).n_type & N_TMASK) == (DT_FCN << N_BTSHFT)))
#   define GCC_SYMINC(X)	((X).n_numaux+1)
#   define GCC_SYMZERO(X)	0
#   define GCC_CHECK_HDR(X)	(1)
#endif

extern char *ldgetname ();

/* 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 (prog_name, which_pass)
     char *prog_name;
     enum pass which_pass;
{
  LDFILE *ldptr = NULL;
  int sym_index, sym_count;

  if (which_pass != PASS_FIRST)
    return;

  if ((ldptr = ldopen (prog_name, ldptr)) == NULL)
    fatal ("%s: can't open as COFF file", prog_name);
      
  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);
      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 _AIX
	      /* All AIX function names begin with a dot. */
	      if (*name++ != '.')
		continue;
#endif

	      switch (is_ctor_dtor (name))
		{
		case 1:
		  add_to_list (&constructors, name);
		  break;

		case 2:
		  add_to_list (&destructors, name);
		  break;

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

#if !defined(EXTENDED_COFF)
	      if (debug)
		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
	      if (debug)
		fprintf (stderr, "\tiss = %5d, value = %5d, index = %5d, name = %s\n",
			 symbol.iss, symbol.value, symbol.index, name);
#endif
	    }
	}
    }

  (void) ldclose(ldptr);
}

#endif /* OBJECT_FORMAT_COFF */


/*
 * OSF/rose specific stuff.
 */

#ifdef OBJECT_FORMAT_ROSE

/* Union of the various load commands */

typedef union load_union
{
  ldc_header_t			hdr;	/* common header */
  load_cmd_map_command_t	map;	/* map indexing other load cmds */
  interpreter_command_t		iprtr;	/* interpreter pathname */
  strings_command_t		str;	/* load commands strings section */
  region_command_t		region;	/* region load command */
  reloc_command_t		reloc;	/* relocation section */
  package_command_t		pkg;	/* package load command */
  symbols_command_t		sym;	/* symbol sections */
  entry_command_t		ent;	/* program start section */
  gen_info_command_t		info;	/* object information */
  func_table_command_t		func;	/* function constructors/destructors */
} load_union_t;

/* Structure to point to load command and data section in memory.  */

typedef struct load_all
{
  load_union_t *load;			/* load command */
  char *section;			/* pointer to section */
} load_all_t;

/* Structure to contain information about a file mapped into memory.  */

struct file_info
{
  char *start;				/* start of map */
  char *name;				/* filename */
  long	size;				/* size of the file */
  long  rounded_size;			/* size rounded to page boundary */
  int	fd;				/* file descriptor */
  int	rw;				/* != 0 if opened read/write */
  int	use_mmap;			/* != 0 if mmap'ed */
};

extern int decode_mach_o_hdr ();

extern int encode_mach_o_hdr ();

static void bad_header ();

static void print_header ();

static void print_load_command ();

static void add_func_table ();

static struct file_info	*read_file ();

static void end_file ();


/* OSF/rose specific 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 (prog_name, which_pass)
     char *prog_name;
     enum pass which_pass;
{
  char *obj;
  mo_header_t hdr;
  load_all_t *load_array;
  load_all_t *load_end;
  load_all_t *load_cmd;
  int symbol_load_cmds;
  off_t offset;
  int i;
  int num_syms;
  int status;
  char *str_sect;
  struct file_info *obj_file;
  int prog_fd;
  mo_lcid_t cmd_strings	  = -1;
  symbol_info_t *main_sym = 0;
  int rw		  = (which_pass != PASS_FIRST);

  prog_fd = open (prog_name, (rw) ? O_RDWR : O_RDONLY);
  if (prog_fd < 0)
    fatal_perror ("can't read %s", prog_name);

  obj_file = read_file (prog_name, prog_fd, rw);
  obj = obj_file->start;

  status = decode_mach_o_hdr (obj, MO_SIZEOF_RAW_HDR, MOH_HEADER_VERSION, &hdr);
  if (status != MO_HDR_CONV_SUCCESS)
    bad_header (status);


  /* Do some basic sanity checks.  Note we explicitly use the big endian magic number,
     since the hardware will automatically swap bytes for us on loading little endian
     integers.  */

#ifndef CROSS_COMPILE
  if (hdr.moh_magic != MOH_MAGIC_MSB
      || hdr.moh_header_version != MOH_HEADER_VERSION
      || hdr.moh_byte_order != OUR_BYTE_ORDER
      || hdr.moh_data_rep_id != OUR_DATA_REP_ID
      || hdr.moh_cpu_type != OUR_CPU_TYPE
      || hdr.moh_cpu_subtype != OUR_CPU_SUBTYPE
      || hdr.moh_vendor_type != OUR_VENDOR_TYPE)
    {
      fatal ("incompatibilities between object file & expected values");
    }
#endif

  if (debug)
    print_header (&hdr);

  offset = hdr.moh_first_cmd_off;
  load_end = load_array
    = (load_all_t *) xcalloc (sizeof (load_all_t), hdr.moh_n_load_cmds + 2);

  /* Build array of load commands, calculating the offsets */
  for (i = 0; i < hdr.moh_n_load_cmds; i++)
    {
      load_union_t *load_hdr;		/* load command header */

      load_cmd = load_end++;
      load_hdr = (load_union_t *) (obj + offset);

      /* If modifying the program file, copy the header.  */
      if (rw)
	{
	  load_union_t *ptr = (load_union_t *) xmalloc (load_hdr->hdr.ldci_cmd_size);
	  bcopy ((generic *)load_hdr, (generic *)ptr, load_hdr->hdr.ldci_cmd_size);
	  load_hdr = ptr;

	  /* null out old command map, because we will rewrite at the end.  */
	  if (ptr->hdr.ldci_cmd_type == LDC_CMD_MAP)
	    {
	      cmd_strings = ptr->map.lcm_ld_cmd_strings;
	      ptr->hdr.ldci_cmd_type = LDC_UNDEFINED;
	    }
	}

      load_cmd->load = load_hdr;
      if (load_hdr->hdr.ldci_section_off > 0)
	load_cmd->section = obj + load_hdr->hdr.ldci_section_off;

      if (debug)
	print_load_command (load_hdr, offset, i);

      offset += load_hdr->hdr.ldci_cmd_size;
    }

  /* If the last command is the load command map and is not undefined,
     decrement the count of load commands.  */
  if (rw && load_end[-1].load->hdr.ldci_cmd_type == LDC_UNDEFINED)
    {
      load_end--;
      hdr.moh_n_load_cmds--;
    }

  /* Go through and process each symbol table section.  */
  symbol_load_cmds = 0;
  for (load_cmd = load_array; load_cmd < load_end; load_cmd++)
    {
      load_union_t *load_hdr = load_cmd->load;

      if (load_hdr->hdr.ldci_cmd_type == LDC_SYMBOLS)
	{
	  symbol_load_cmds++;

	  if (debug)
	    {
	      char *kind = "unknown";

	      switch (load_hdr->sym.symc_kind)
		{
		case SYMC_IMPORTS:	   kind = "imports"; break;
		case SYMC_DEFINED_SYMBOLS: kind = "defined"; break;