dbxread.c

早期freebsd实现

{
  register struct header_file *f = &header_files[real_filenum];

  if (index >= f->length)
    {
      f->length *= 2;
      f->vector = (struct type **)
	xrealloc (f->vector, f->length * sizeof (struct type *));
      bzero (&f->vector[f->length / 2],
	     f->length * sizeof (struct type *) / 2);
    }
  return &f->vector[index];
}
#endif

static void
record_minimal_symbol (name, address, type, objfile)
     char *name;
     CORE_ADDR address;
     int type;
     struct objfile *objfile;
{
  enum minimal_symbol_type ms_type;

  switch (type &~ N_EXT) {
    case N_TEXT:  ms_type = mst_text; break;
    case N_DATA:  ms_type = mst_data; break;
    case N_BSS:   ms_type = mst_bss;  break;
    case N_ABS:   ms_type = mst_abs;  break;
#ifdef N_SETV
    case N_SETV:  ms_type = mst_data; break;
#endif
    default:      ms_type = mst_unknown; break;
  }

  prim_record_minimal_symbol (obsavestring (name, strlen (name), &objfile -> symbol_obstack),
			     address, ms_type);
}

/* Scan and build partial symbols for a symbol file.
   We have been initialized by a call to dbx_symfile_init, which 
   put all the relevant info into a "struct dbx_symfile_info",
   hung off the objfile structure.

   SECTION_OFFSETS contains offsets relative to which the symbols in the
   various sections are (depending where the sections were actually loaded).
   MAINLINE is true if we are reading the main symbol
   table (as opposed to a shared lib or dynamically loaded file).  */

static void
dbx_symfile_read (objfile, section_offsets, mainline)
     struct objfile *objfile;
     struct section_offsets *section_offsets;
     int mainline;	/* FIXME comments above */
{
  bfd *sym_bfd;
  int val;

  sym_bfd = objfile->obfd;
  val = bfd_seek (objfile->obfd, DBX_SYMTAB_OFFSET (objfile), L_SET);
  if (val < 0)
    perror_with_name (objfile->name);

  /* If we are reinitializing, or if we have never loaded syms yet, init */
  if (mainline || objfile->global_psymbols.size == 0 || objfile->static_psymbols.size == 0)
    init_psymbol_list (objfile);

#ifdef GDB_TARGET_IS_HPPA
  symbol_size = obj_dbx_symbol_entry_size (sym_bfd);
#else
  symbol_size = DBX_SYMBOL_SIZE (objfile);
#endif
  symbol_table_offset = DBX_SYMTAB_OFFSET (objfile);

  pending_blocks = 0;
  make_cleanup (really_free_pendings, 0);

  init_minimal_symbol_collection ();
  make_cleanup (discard_minimal_symbols, 0);

  /* Now that the symbol table data of the executable file are all in core,
     process them and define symbols accordingly.  */

  read_dbx_symtab (section_offsets, objfile,
		   bfd_section_vma  (sym_bfd, DBX_TEXT_SECT (objfile)),
		   bfd_section_size (sym_bfd, DBX_TEXT_SECT (objfile)));

  /* Install any minimal symbols that have been collected as the current
     minimal symbols for this objfile. */

  install_minimal_symbols (objfile);

  if (!have_partial_symbols ()) {
    wrap_here ("");
    printf_filtered ("(no debugging symbols found)...");
    wrap_here ("");
  }
}

/* Initialize anything that needs initializing when a completely new
   symbol file is specified (not just adding some symbols from another
   file, e.g. a shared library).  */

static void
dbx_new_init (ignore)
     struct objfile *ignore;
{
  stabsread_new_init ();
  buildsym_new_init ();
  init_header_files ();
}


/* dbx_symfile_init ()
   is the dbx-specific initialization routine for reading symbols.
   It is passed a struct objfile which contains, among other things,
   the BFD for the file whose symbols are being read, and a slot for a pointer
   to "private data" which we fill with goodies.

   We read the string table into malloc'd space and stash a pointer to it.

   Since BFD doesn't know how to read debug symbols in a format-independent
   way (and may never do so...), we have to do it ourselves.  We will never
   be called unless this is an a.out (or very similar) file. 
   FIXME, there should be a cleaner peephole into the BFD environment here.  */

static void
dbx_symfile_init (objfile)
     struct objfile *objfile;
{
  int val;
  bfd *sym_bfd = objfile->obfd;
  char *name = bfd_get_filename (sym_bfd);
  unsigned char size_temp[4];

  /* Allocate struct to keep track of the symfile */
  objfile->sym_private = (PTR)
    xmmalloc (objfile -> md, sizeof (struct dbx_symfile_info));

  /* FIXME POKING INSIDE BFD DATA STRUCTURES */
#ifdef GDB_TARGET_IS_HPPA
#define STRING_TABLE_OFFSET  (sym_bfd->origin + obj_dbx_str_filepos (sym_bfd))
#define SYMBOL_TABLE_OFFSET  (sym_bfd->origin + obj_dbx_sym_filepos (sym_bfd))
#define HP_STRING_TABLE_OFFSET  (sym_bfd->origin + obj_hp_str_filepos (sym_bfd))
#define HP_SYMBOL_TABLE_OFFSET  (sym_bfd->origin + obj_hp_sym_filepos (sym_bfd))
#else
#define	STRING_TABLE_OFFSET	(sym_bfd->origin + obj_str_filepos (sym_bfd))
#define	SYMBOL_TABLE_OFFSET	(sym_bfd->origin + obj_sym_filepos (sym_bfd))
#endif
  /* FIXME POKING INSIDE BFD DATA STRUCTURES */

  DBX_SYMFILE_INFO (objfile)->stab_section_info = NULL;
  DBX_TEXT_SECT (objfile) = bfd_get_section_by_name (sym_bfd, ".text");
  if (!DBX_TEXT_SECT (objfile))
    error ("Can't find .text section in symbol file");

#ifdef GDB_TARGET_IS_HPPA
  HP_SYMCOUNT (objfile) = obj_hp_sym_count (sym_bfd);
  DBX_SYMCOUNT (objfile) = obj_dbx_sym_count (sym_bfd);
#else
  DBX_SYMBOL_SIZE (objfile) = obj_symbol_entry_size (sym_bfd);
  DBX_SYMCOUNT (objfile) = bfd_get_symcount (sym_bfd);
#endif
  DBX_SYMTAB_OFFSET (objfile) = SYMBOL_TABLE_OFFSET;

  /* Read the string table and stash it away in the psymbol_obstack.  It is
     only needed as long as we need to expand psymbols into full symbols,
     so when we blow away the psymbol the string table goes away as well.
     Note that gdb used to use the results of attempting to malloc the
     string table, based on the size it read, as a form of sanity check
     for botched byte swapping, on the theory that a byte swapped string
     table size would be so totally bogus that the malloc would fail.  Now
     that we put in on the psymbol_obstack, we can't do this since gdb gets
     a fatal error (out of virtual memory) if the size is bogus.  We can
     however at least check to see if the size is zero or some negative
     value. */

#ifdef GDB_TARGET_IS_HPPA
  DBX_STRINGTAB_SIZE (objfile) = obj_dbx_stringtab_size (sym_bfd);
  HP_STRINGTAB_SIZE (objfile) = obj_hp_stringtab_size (sym_bfd);
#else
  val = bfd_seek (sym_bfd, STRING_TABLE_OFFSET, L_SET);
  if (val < 0)
    perror_with_name (name);

  val = bfd_read ((PTR)size_temp, sizeof (long), 1, sym_bfd);
  if (val < 0)
    perror_with_name (name);

  DBX_STRINGTAB_SIZE (objfile) = bfd_h_get_32 (sym_bfd, size_temp);
#endif

  if (DBX_STRINGTAB_SIZE (objfile) <= 0)
    error ("ridiculous string table size (%d bytes).",
	   DBX_STRINGTAB_SIZE (objfile));

  DBX_STRINGTAB (objfile) =
    (char *) obstack_alloc (&objfile -> psymbol_obstack,
			    DBX_STRINGTAB_SIZE (objfile));
#ifdef GDB_TARGET_IS_HPPA
  if (HP_STRINGTAB_SIZE (objfile) <= 0)
    error ("ridiculous string table size (%d bytes).",
	   HP_STRINGTAB_SIZE (objfile));

  HP_STRINGTAB (objfile) =
    (char *) obstack_alloc (&objfile -> psymbol_obstack,
			    HP_STRINGTAB_SIZE (objfile));
#endif

  /* Now read in the string table in one big gulp.  */

  val = bfd_seek (sym_bfd, STRING_TABLE_OFFSET, L_SET);
  if (val < 0)
    perror_with_name (name);
  val = bfd_read (DBX_STRINGTAB (objfile), DBX_STRINGTAB_SIZE (objfile), 1,
		  sym_bfd);
  if (val != DBX_STRINGTAB_SIZE (objfile))
    perror_with_name (name);
#ifdef GDB_TARGET_IS_HPPA
  val = bfd_seek (sym_bfd, HP_STRING_TABLE_OFFSET, L_SET);
  if (val < 0)
    perror_with_name (name);
  val = bfd_read (HP_STRINGTAB (objfile), HP_STRINGTAB_SIZE (objfile), 1,
		  sym_bfd);
  if (val != HP_STRINGTAB_SIZE (objfile))
    perror_with_name (name);
#endif
#ifdef GDB_TARGET_IS_HPPA
  HP_SYMTAB_OFFSET (objfile) = HP_SYMBOL_TABLE_OFFSET;
#endif
}

/* Perform any local cleanups required when we are done with a particular
   objfile.  I.E, we are in the process of discarding all symbol information
   for an objfile, freeing up all memory held for it, and unlinking the
   objfile struct from the global list of known objfiles. */

static void
dbx_symfile_finish (objfile)
     struct objfile *objfile;
{
  if (objfile->sym_private != NULL)
    {
      mfree (objfile -> md, objfile->sym_private);
    }
  free_header_files ();
}


/* Buffer for reading the symbol table entries.  */
static struct internal_nlist symbuf[4096];
static int symbuf_idx;
static int symbuf_end;

/* Name of last function encountered.  Used in Solaris to approximate
   object file boundaries.  */
static char *last_function_name;

/* The address in memory of the string table of the object file we are
   reading (which might not be the "main" object file, but might be a
   shared library or some other dynamically loaded thing).  This is set
   by read_dbx_symtab when building psymtabs, and by read_ofile_symtab 
   when building symtabs, and is used only by next_symbol_text.  */
static char *stringtab_global;

/* Refill the symbol table input buffer
   and set the variables that control fetching entries from it.
   Reports an error if no data available.
   This function can read past the end of the symbol table
   (into the string table) but this does no harm.  */

static void
fill_symbuf (sym_bfd)
     bfd *sym_bfd;
{
  int nbytes = bfd_read ((PTR)symbuf, sizeof (symbuf), 1, sym_bfd);
  if (nbytes < 0)
    perror_with_name (bfd_get_filename (sym_bfd));
  else if (nbytes == 0)
    error ("Premature end of file reading symbol table");
  symbuf_end = nbytes / symbol_size;
  symbuf_idx = 0;
}
#ifdef GDB_TARGET_IS_HPPA
/* same as above for the HP symbol table */

static struct symbol_dictionary_record hp_symbuf[4096];
static int hp_symbuf_idx;
static int hp_symbuf_end;

static int
fill_hp_symbuf (sym_bfd)
     bfd *sym_bfd;
{
  int nbytes = bfd_read ((PTR)hp_symbuf, sizeof (hp_symbuf), 1, sym_bfd);
  if (nbytes <= 0)
    error ("error or end of file reading symbol table");
  hp_symbuf_end = nbytes / sizeof (struct symbol_dictionary_record);
  hp_symbuf_idx = 0;
  return 1;
}
#endif

#define SWAP_SYMBOL(symp, abfd) \
  { \
    (symp)->n_strx = bfd_h_get_32(abfd,			\
				(unsigned char *)&(symp)->n_strx);	\
    (symp)->n_desc = bfd_h_get_16 (abfd,			\
				(unsigned char *)&(symp)->n_desc);  	\
    (symp)->n_value = bfd_h_get_32 (abfd,			\
				(unsigned char *)&(symp)->n_value); 	\
  }

/* Invariant: The symbol pointed to by symbuf_idx is the first one
   that hasn't been swapped.  Swap the symbol at the same time
   that symbuf_idx is incremented.  */

/* dbx allows the text of a symbol name to be continued into the
   next symbol name!  When such a continuation is encountered
   (a \ at the end of the text of a name)
   call this function to get the continuation.  */

static char *
dbx_next_symbol_text ()
{
  if (symbuf_idx == symbuf_end)
    fill_symbuf (symfile_bfd);
  symnum++;
  SWAP_SYMBOL(&symbuf[symbuf_idx], symfile_bfd);
  return symbuf[symbuf_idx++].n_strx + stringtab_global
	  + file_string_table_offset;
}

/* Initializes storage for all of the partial symbols that will be
   created by read_dbx_symtab and subsidiaries.  */

static void
init_psymbol_list (objfile)
     struct objfile *objfile;
{
  /* Free any previously allocated psymbol lists.  */
  if (objfile -> global_psymbols.list)
    mfree (objfile -> md, (PTR)objfile -> global_psymbols.list);
  if (objfile -> static_psymbols.list)
    mfree (objfile -> md, (PTR)objfile -> static_psymbols.list);

  /* Current best guess is that there are approximately a twentieth
     of the total symbols (in a debugging file) are global or static
     oriented symbols */
#ifdef GDB_TARGET_IS_HPPA
  objfile -> global_psymbols.size = (DBX_SYMCOUNT (objfile) + 
				     HP_SYMCOUNT (objfile)) / 10;
  objfile -> static_psymbols.size = (DBX_SYMCOUNT (objfile) +
				     HP_SYMCOUNT (objfile)) / 10;
#else
  objfile -> global_psymbols.size = DBX_SYMCOUNT (objfile) / 10;
  objfile -> static_psymbols.size = DBX_SYMCOUNT (objfile) / 10;
#endif
  objfile -> global_psymbols.next = objfile -> global_psymbols.list = (struct partial_symbol *)
    xmmalloc (objfile -> md, objfile -> global_psymbols.size * sizeof (struct partial_symbol));
  objfile -> static_psymbols.next = objfile -> static_psymbols.list = (struct partial_symbol *)
    xmmalloc (objfile -> md, objfile -> static_psymbols.size * sizeof (struct partial_symbol));
}

/* Initialize the list of bincls to contain none and have some
   allocated.  */

static void
init_bincl_list (number, objfile)
     int number;
     struct objfile *objfile;
{
  bincls_allocated = number;
  next_bincl = bincl_list = (struct header_file_location *)
    xmmalloc (objfile -> md, bincls_allocated * sizeof(struct header_file_location));
}

/* Add a bincl to the list.  */

static void
add_bincl_to_list (pst, name, instance)
     struct partial_symtab *pst;
     char *name;
     int instance;
{
  if (next_bincl >= bincl_list + bincls_allocated)
    {
      int offset = next_bincl - bincl_list;
      bincls_allocated *= 2;
      bincl_list = (struct header_file_location *)
	xmrealloc (pst->objfile->md, (char *)bincl_list,
		  bincls_allocated * sizeof (struct header_file_location));
      next_bincl = bincl_list + offset;
    }
  next_bincl->pst = pst;
  next_bincl->instance = instance;
  next_bincl++->name = name;
}