dwarfread.c

早期freebsd实现

	Decode the language attribute for a compilation unit DIE and
	remember what the language was.  We use this at various times
	when processing DIE's for a given compilation unit.

RETURNS

	No return value.

 */

static void
set_cu_language (dip)
     struct dieinfo *dip;
{
  switch (dip -> at_language)
    {
      case LANG_C89:
      case LANG_C:
        cu_language = language_c;
	break;
      case LANG_C_PLUS_PLUS:
	cu_language = language_cplus;
	break;
      case LANG_ADA83:
      case LANG_COBOL74:
      case LANG_COBOL85:
      case LANG_FORTRAN77:
      case LANG_FORTRAN90:
      case LANG_PASCAL83:
      case LANG_MODULA2:
      default:
	cu_language = language_unknown;
	break;
    }
}

/*

GLOBAL FUNCTION

	dwarf_build_psymtabs -- build partial symtabs from DWARF debug info

SYNOPSIS

	void dwarf_build_psymtabs (struct objfile *objfile,
	     struct section_offsets *section_offsets,
	     int mainline, file_ptr dbfoff, unsigned int dbfsize,
	     file_ptr lnoffset, unsigned int lnsize)

DESCRIPTION

	This function is called upon to build partial symtabs from files
	containing DIE's (Dwarf Information Entries) and DWARF line numbers.

	It is passed a bfd* containing the DIES
	and line number information, the corresponding filename for that
	file, a base address for relocating the symbols, a flag indicating
	whether or not this debugging information is from a "main symbol
	table" rather than a shared library or dynamically linked file,
	and file offset/size pairs for the DIE information and line number
	information.

RETURNS

	No return value.

 */

void
dwarf_build_psymtabs (objfile, section_offsets, mainline, dbfoff, dbfsize,
		      lnoffset, lnsize)
     struct objfile *objfile;
     struct section_offsets *section_offsets;
     int mainline;
     file_ptr dbfoff;
     unsigned int dbfsize;
     file_ptr lnoffset;
     unsigned int lnsize;
{
  bfd *abfd = objfile->obfd;
  struct cleanup *back_to;
  
  current_objfile = objfile;
  dbsize = dbfsize;
  dbbase = xmalloc (dbsize);
  dbroff = 0;
  if ((bfd_seek (abfd, dbfoff, L_SET) != 0) ||
      (bfd_read (dbbase, dbsize, 1, abfd) != dbsize))
    {
      free (dbbase);
      error ("can't read DWARF data from '%s'", bfd_get_filename (abfd));
    }
  back_to = make_cleanup (free, dbbase);
  
  /* If we are reinitializing, or if we have never loaded syms yet, init.
     Since we have no idea how many DIES we are looking at, we just guess
     some arbitrary value. */
  
  if (mainline || objfile -> global_psymbols.size == 0 ||
      objfile -> static_psymbols.size == 0)
    {
      init_psymbol_list (objfile, 1024);
    }
  
  /* Save the relocation factor where everybody can see it.  */

  base_section_offsets = section_offsets;
  baseaddr = ANOFFSET (section_offsets, 0);

  /* Follow the compilation unit sibling chain, building a partial symbol
     table entry for each one.  Save enough information about each compilation
     unit to locate the full DWARF information later. */
  
  scan_compilation_units (dbbase, dbbase + dbsize, dbfoff, lnoffset, objfile);
  
  do_cleanups (back_to);
  current_objfile = NULL;
}


/*

LOCAL FUNCTION

	record_minimal_symbol -- add entry to gdb's minimal symbol table

SYNOPSIS

	static void record_minimal_symbol (char *name, CORE_ADDR address,
					  enum minimal_symbol_type ms_type,
					  struct objfile *objfile)

DESCRIPTION

	Given a pointer to the name of a symbol that should be added to the
	minimal symbol table, and the address associated with that
	symbol, records this information for later use in building the
	minimal symbol table.

 */

static void
record_minimal_symbol (name, address, ms_type, objfile)
     char *name;
     CORE_ADDR address;
     enum minimal_symbol_type ms_type;
     struct objfile *objfile;
{
  name = obsavestring (name, strlen (name), &objfile -> symbol_obstack);
  prim_record_minimal_symbol (name, address, ms_type);
}

/*

LOCAL FUNCTION

	dwarfwarn -- issue a DWARF related warning

DESCRIPTION

	Issue warnings about DWARF related things that aren't serious enough
	to warrant aborting with an error, but should not be ignored either.
	This includes things like detectable corruption in DIE's, missing
	DIE's, unimplemented features, etc.

	In general, running across tags or attributes that we don't recognize
	is not considered to be a problem and we should not issue warnings
	about such.

NOTES

	We mostly follow the example of the error() routine, but without
	returning to command level.  It is arguable about whether warnings
	should be issued at all, and if so, where they should go (stdout or
	stderr).

	We assume that curdie is valid and contains at least the basic
	information for the DIE where the problem was noticed.
*/

static void
dwarfwarn (va_alist)
     va_dcl
{
  va_list ap;
  char *fmt;
  
  va_start (ap);
  fmt = va_arg (ap, char *);
  warning_setup ();
  fprintf (stderr, "warning: DWARF ref 0x%x: ", curdie -> die_ref);
  if (curdie -> at_name)
    {
      fprintf (stderr, "'%s': ", curdie -> at_name);
    }
  vfprintf (stderr, fmt, ap);
  fprintf (stderr, "\n");
  fflush (stderr);
  va_end (ap);
}

/*

LOCAL FUNCTION

	read_lexical_block_scope -- process all dies in a lexical block

SYNOPSIS

	static void read_lexical_block_scope (struct dieinfo *dip,
		char *thisdie, char *enddie)

DESCRIPTION

	Process all the DIES contained within a lexical block scope.
	Start a new scope, process the dies, and then close the scope.

 */

static void
read_lexical_block_scope (dip, thisdie, enddie, objfile)
     struct dieinfo *dip;
     char *thisdie;
     char *enddie;
     struct objfile *objfile;
{
  register struct context_stack *new;

  push_context (0, dip -> at_low_pc);
  process_dies (thisdie + dip -> die_length, enddie, objfile);
  new = pop_context ();
  if (local_symbols != NULL)
    {
      finish_block (0, &local_symbols, new -> old_blocks, new -> start_addr,
		    dip -> at_high_pc, objfile);
    }
  local_symbols = new -> locals;
}

/*

LOCAL FUNCTION

	lookup_utype -- look up a user defined type from die reference

SYNOPSIS

	static type *lookup_utype (DIE_REF die_ref)

DESCRIPTION

	Given a DIE reference, lookup the user defined type associated with
	that DIE, if it has been registered already.  If not registered, then
	return NULL.  Alloc_utype() can be called to register an empty
	type for this reference, which will be filled in later when the
	actual referenced DIE is processed.
 */

static struct type *
lookup_utype (die_ref)
     DIE_REF die_ref;
{
  struct type *type = NULL;
  int utypeidx;
  
  utypeidx = (die_ref - dbroff) / 4;
  if ((utypeidx < 0) || (utypeidx >= numutypes))
    {
      dwarfwarn ("reference to DIE (0x%x) outside compilation unit", die_ref);
    }
  else
    {
      type = *(utypes + utypeidx);
    }
  return (type);
}


/*

LOCAL FUNCTION

	alloc_utype  -- add a user defined type for die reference

SYNOPSIS

	static type *alloc_utype (DIE_REF die_ref, struct type *utypep)

DESCRIPTION

	Given a die reference DIE_REF, and a possible pointer to a user
	defined type UTYPEP, register that this reference has a user
	defined type and either use the specified type in UTYPEP or
	make a new empty type that will be filled in later.

	We should only be called after calling lookup_utype() to verify that
	there is not currently a type registered for DIE_REF.
 */

static struct type *
alloc_utype (die_ref, utypep)
     DIE_REF die_ref;
     struct type *utypep;
{
  struct type **typep;
  int utypeidx;
  
  utypeidx = (die_ref - dbroff) / 4;
  typep = utypes + utypeidx;
  if ((utypeidx < 0) || (utypeidx >= numutypes))
    {
      utypep = lookup_fundamental_type (current_objfile, FT_INTEGER);
      dwarfwarn ("reference to DIE (0x%x) outside compilation unit", die_ref);
    }
  else if (*typep != NULL)
    {
      utypep = *typep;
      SQUAWK (("internal error: dup user type allocation"));
    }
  else
    {
      if (utypep == NULL)
	{
	  utypep = alloc_type (current_objfile);
	}
      *typep = utypep;
    }
  return (utypep);
}

/*

LOCAL FUNCTION

	decode_die_type -- return a type for a specified die

SYNOPSIS

	static struct type *decode_die_type (struct dieinfo *dip)

DESCRIPTION

	Given a pointer to a die information structure DIP, decode the
	type of the die and return a pointer to the decoded type.  All
	dies without specific types default to type int.
 */

static struct type *
decode_die_type (dip)
     struct dieinfo *dip;
{
  struct type *type = NULL;
  
  if (dip -> at_fund_type != 0)
    {
      type = decode_fund_type (dip -> at_fund_type);
    }
  else if (dip -> at_mod_fund_type != NULL)
    {
      type = decode_mod_fund_type (dip -> at_mod_fund_type);
    }
  else if (dip -> at_user_def_type)
    {
      if ((type = lookup_utype (dip -> at_user_def_type)) == NULL)
	{
	  type = alloc_utype (dip -> at_user_def_type, NULL);
	}
    }
  else if (dip -> at_mod_u_d_type)
    {
      type = decode_mod_u_d_type (dip -> at_mod_u_d_type);
    }
  else
    {
      type = lookup_fundamental_type (current_objfile, FT_INTEGER);
    }
  return (type);
}

/*

LOCAL FUNCTION

	struct_type -- compute and return the type for a struct or union

SYNOPSIS

	static struct type *struct_type (struct dieinfo *dip, char *thisdie,
	    char *enddie, struct objfile *objfile)

DESCRIPTION

	Given pointer to a die information structure for a die which
	defines a union or structure (and MUST define one or the other),
	and pointers to the raw die data that define the range of dies which
	define the members, compute and return the user defined type for the
	structure or union.
 */

static struct type *
struct_type (dip, thisdie, enddie, objfile)
     struct dieinfo *dip;
     char *thisdie;
     char *enddie;
     struct objfile *objfile;
{
  struct type *type;
  struct nextfield {
    struct nextfield *next;
    struct field field;
  };
  struct nextfield *list = NULL;
  struct nextfield *new;
  int nfields = 0;
  int n;
  char *tpart1;
  struct dieinfo mbr;
  char *nextdie;
  int anonymous_size;
  
  if ((type = lookup_utype (dip -> die_ref)) == NULL)
    {
      /* No forward references created an empty type, so install one now */
      type = alloc_utype (dip -> die_ref, NULL);
    }
  INIT_CPLUS_SPECIFIC(type);
  switch (dip -> die_tag)
    {
      case TAG_class_type:
        TYPE_CODE (type) = TYPE_CODE_CLASS;
	tpart1 = "class";
	break;
      case TAG_structure_type:
        TYPE_CODE (type) = TYPE_CODE_STRUCT;
	tpart1 = "struct";
	break;
      case TAG_union_type:
	TYPE_CODE (type) = TYPE_CODE_UNION;
	tpart1 = "union";
	break;
      default:
	/* Should never happen */
	TYPE_CODE (type) = TYPE_CODE_UNDEF;
	tpart1 = "???";
	SQUAWK (("missing class, structure, or union tag"));
	break;
    }
  /* Some compilers try to be helpful by inventing "fake" names for
     anonymous enums, structures, and unions, like "~0fake" or ".0fake".
     Thanks, but no thanks... */
  if (dip -> at_name != NULL
      && *dip -> at_name != '~'
      && *dip -> at_name != '.')
    {
      TYPE_NAME (type) = obconcat (&objfile -> type_obstack,
				   tpart1, " ", dip -> at_name);
    }
  /* Use whatever size is known.  Zero is a valid size.  We might however
     wish to check has_at_byte_size to make sure that some byte size was
     given explicitly, but DWARF doesn't specify that explicit sizes of
     zero have to present, so complaining about missing sizes should 
     probably not be the default. */
  TYPE_LENGTH (type) = dip -> at_byte_size;
  thisdie += dip -> die_length;
  while (thisdie < enddie)