dbxout.c

gcc库的原代码,对编程有很大帮助.

		  CHARS (IDENTIFIER_LENGTH (name) + 2);
		  need_prefix = 0;
		}
	    }

	  dbxout_type (TREE_TYPE (fndecl), 0, destructor);

	  dbxout_type_method_1 (fndecl, debug_name);
	}
      if (!need_prefix)
	{
          putc (';', asmfile);
	  CHARS (1);
	}
    }
}

/* Emit a "range" type specification, which has the form:
   "r<index type>;<lower bound>;<upper bound>;".
   TYPE is an INTEGER_TYPE. */

static void
dbxout_range_type (type)
     tree type;
{
  fprintf (asmfile, "r");
  if (TREE_TYPE (type))
    dbxout_type (TREE_TYPE (type), 0, 0);
  else if (TREE_CODE (type) != INTEGER_TYPE)
    dbxout_type (type, 0, 0); /* E.g. Pascal's ARRAY [BOOLEAN] of INTEGER */
  else
    {
      /* This used to say `r1' and we used to take care
	 to make sure that `int' was type number 1.  */
      fprintf (asmfile, "%d", TYPE_SYMTAB_ADDRESS (integer_type_node));
    }
  if (TREE_CODE (TYPE_MIN_VALUE (type)) == INTEGER_CST)
    fprintf (asmfile, ";%d", 
	     TREE_INT_CST_LOW (TYPE_MIN_VALUE (type)));
  else
    fprintf (asmfile, ";0");
  if (TREE_CODE (TYPE_MAX_VALUE (type)) == INTEGER_CST)
    fprintf (asmfile, ";%d;", 
	     TREE_INT_CST_LOW (TYPE_MAX_VALUE (type)));
  else
    fprintf (asmfile, ";-1;");
}

/* Output a reference to a type.  If the type has not yet been
   described in the dbx output, output its definition now.
   For a type already defined, just refer to its definition
   using the type number.

   If FULL is nonzero, and the type has been described only with
   a forward-reference, output the definition now.
   If FULL is zero in this case, just refer to the forward-reference
   using the number previously allocated.

   If SHOW_ARG_TYPES is nonzero, we output a description of the argument
   types for a METHOD_TYPE.  */

static void
dbxout_type (type, full, show_arg_types)
     tree type;
     int full;
     int show_arg_types;
{
  register tree tem;
  static int anonymous_type_number = 0;

  /* If there was an input error and we don't really have a type,
     avoid crashing and write something that is at least valid
     by assuming `int'.  */
  if (type == error_mark_node)
    type = integer_type_node;
  else
    {
      type = TYPE_MAIN_VARIANT (type);
      if (TYPE_NAME (type)
	  && TREE_CODE (TYPE_NAME (type)) == TYPE_DECL
	  && TYPE_DECL_SUPPRESS_DEBUG (TYPE_NAME (type)))
	full = 0;
    }

  if (TYPE_SYMTAB_ADDRESS (type) == 0)
    {
      /* Type has no dbx number assigned.  Assign next available number.  */
      TYPE_SYMTAB_ADDRESS (type) = next_type_number++;

      /* Make sure type vector is long enough to record about this type.  */

      if (next_type_number == typevec_len)
	{
	  typevec =
	    (enum typestatus *) xrealloc (typevec,
					  typevec_len * 2 * sizeof typevec[0]);
	  bzero ((char *) (typevec + typevec_len),
		 typevec_len * sizeof typevec[0]);
	  typevec_len *= 2;
	}
    }

  /* Output the number of this type, to refer to it.  */
  fprintf (asmfile, "%d", TYPE_SYMTAB_ADDRESS (type));
  CHARS (3);

#ifdef DBX_TYPE_DEFINED
  if (DBX_TYPE_DEFINED (type))
    return;
#endif

  /* If this type's definition has been output or is now being output,
     that is all.  */

  switch (typevec[TYPE_SYMTAB_ADDRESS (type)])
    {
    case TYPE_UNSEEN:
      break;
    case TYPE_XREF:
      /* If we have already had a cross reference,
	 and either that's all we want or that's the best we could do,
	 don't repeat the cross reference.
	 Sun dbx crashes if we do.  */
      if (! full || TYPE_SIZE (type) == 0
	  /* No way in DBX fmt to describe a variable size.  */
	  || TREE_CODE (TYPE_SIZE (type)) != INTEGER_CST)
	return;
      break;
    case TYPE_DEFINED:
      return;
    }

#ifdef DBX_NO_XREFS
  /* For systems where dbx output does not allow the `=xsNAME:' syntax,
     leave the type-number completely undefined rather than output
     a cross-reference.  If we have already used GNU debug info extensions,
     then it is OK to output a cross reference.  This is necessary to get
     proper C++ debug output.  */
  if ((TREE_CODE (type) == RECORD_TYPE || TREE_CODE (type) == UNION_TYPE
       || TREE_CODE (type) == QUAL_UNION_TYPE
       || TREE_CODE (type) == ENUMERAL_TYPE)
      && ! use_gnu_debug_info_extensions)
    /* We must use the same test here as we use twice below when deciding
       whether to emit a cross-reference.  */
    if ((TYPE_NAME (type) != 0
	 && ! (TREE_CODE (TYPE_NAME (type)) == TYPE_DECL
	       && DECL_IGNORED_P (TYPE_NAME (type)))
	 && !full)
	|| TYPE_SIZE (type) == 0
	/* No way in DBX fmt to describe a variable size.  */
	|| TREE_CODE (TYPE_SIZE (type)) != INTEGER_CST)
      {
	typevec[TYPE_SYMTAB_ADDRESS (type)] = TYPE_XREF;
	return;
      }
#endif

  /* Output a definition now.  */

  fprintf (asmfile, "=");
  CHARS (1);

  /* Mark it as defined, so that if it is self-referent
     we will not get into an infinite recursion of definitions.  */

  typevec[TYPE_SYMTAB_ADDRESS (type)] = TYPE_DEFINED;

  switch (TREE_CODE (type))
    {
    case VOID_TYPE:
    case LANG_TYPE:
      /* For a void type, just define it as itself; ie, "5=5".
	 This makes us consider it defined
	 without saying what it is.  The debugger will make it
	 a void type when the reference is seen, and nothing will
	 ever override that default.  */
      fprintf (asmfile, "%d", TYPE_SYMTAB_ADDRESS (type));
      CHARS (3);
      break;

    case INTEGER_TYPE:
      if (type == char_type_node && ! TREE_UNSIGNED (type))
	/* Output the type `char' as a subrange of itself!
	   I don't understand this definition, just copied it
	   from the output of pcc.
	   This used to use `r2' explicitly and we used to
	   take care to make sure that `char' was type number 2.  */
	fprintf (asmfile, "r%d;0;127;", TYPE_SYMTAB_ADDRESS (type));
      else if (use_gnu_debug_info_extensions
	       && (TYPE_PRECISION (type) > TYPE_PRECISION (integer_type_node)
		   || TYPE_PRECISION (type) > HOST_BITS_PER_WIDE_INT))
	{
	  /* This used to say `r1' and we used to take care
	     to make sure that `int' was type number 1.  */
	  fprintf (asmfile, "r%d;", TYPE_SYMTAB_ADDRESS (integer_type_node));
	  print_int_cst_octal (TYPE_MIN_VALUE (type));
	  fprintf (asmfile, ";");
	  print_int_cst_octal (TYPE_MAX_VALUE (type));
	  fprintf (asmfile, ";");
	}
      else /* Output other integer types as subranges of `int'.  */
	dbxout_range_type (type);
      CHARS (25);
      break;

    case REAL_TYPE:
      /* This used to say `r1' and we used to take care
	 to make sure that `int' was type number 1.  */
      fprintf (asmfile, "r%d;%d;0;", TYPE_SYMTAB_ADDRESS (integer_type_node),
	       int_size_in_bytes (type));
      CHARS (16);
      break;

    case CHAR_TYPE:
      if (use_gnu_debug_info_extensions)
	fprintf (asmfile, "@s%d;-20;",
		 BITS_PER_UNIT * int_size_in_bytes (type));
      else
	/* Output the type `char' as a subrange of itself.
	   That is what pcc seems to do.  */
      fprintf (asmfile, "r%d;0;%d;", TYPE_SYMTAB_ADDRESS (char_type_node),
	       TREE_UNSIGNED (type) ? 255 : 127);
      CHARS (9);
      break;

    case BOOLEAN_TYPE:
      if (use_gnu_debug_info_extensions)
	fprintf (asmfile, "@s%d;-16;",
		 BITS_PER_UNIT * int_size_in_bytes (type));
      else /* Define as enumeral type (False, True) */
	fprintf (asmfile, "eFalse:0,True:1,;");
      CHARS (17);
      break;

    case FILE_TYPE:
      putc ('d', asmfile);
      CHARS (1);
      dbxout_type (TREE_TYPE (type), 0, 0);
      break;

    case COMPLEX_TYPE:
      /* Differs from the REAL_TYPE by its new data type number */

      if (TREE_CODE (TREE_TYPE (type)) == REAL_TYPE)
	{
	  fprintf (asmfile, "r%d;%d;0;",
		   TYPE_SYMTAB_ADDRESS (type),
		   int_size_in_bytes (TREE_TYPE (type)));
	  CHARS (15);		/* The number is probably incorrect here.  */
	}
      else
	{
	  /* Output a complex integer type as a structure,
	     pending some other way to do it.  */
	  fprintf (asmfile, "s%d", int_size_in_bytes (type));

	  fprintf (asmfile, "real:");
	  CHARS (10);
	  dbxout_type (TREE_TYPE (type), 0, 0);
	  fprintf (asmfile, ",%d,%d;",
		   0, TYPE_PRECISION (TREE_TYPE (type)));
	  CHARS (8);
	  fprintf (asmfile, "imag:");
	  CHARS (5);
	  dbxout_type (TREE_TYPE (type), 0, 0);
	  fprintf (asmfile, ",%d,%d;;",
		   TYPE_PRECISION (TREE_TYPE (type)),
		   TYPE_PRECISION (TREE_TYPE (type)));
	  CHARS (9);
	}
      break;

    case SET_TYPE:
      if (use_gnu_debug_info_extensions)
	{
	  have_used_extensions = 1;
	  fprintf (asmfile, "@s%d;",
		   BITS_PER_UNIT * int_size_in_bytes (type));
	  /* Check if a bitstring type, which in Chill is
	     different from a [power]set. */
	  if (TYPE_STRING_FLAG (type))
	    fprintf (asmfile, "@S;");
	}
      putc ('S', asmfile);
      CHARS (1);
      dbxout_type (TYPE_DOMAIN (type), 0, 0);
      break;

    case ARRAY_TYPE:
      /* Output "a" followed by a range type definition
	 for the index type of the array
	 followed by a reference to the target-type.
	 ar1;0;N;M for a C array of type M and size N+1.  */
      /* Check if a character string type, which in Chill is
	 different from an array of characters. */
      if (TYPE_STRING_FLAG (type) && use_gnu_debug_info_extensions)
	{
	  have_used_extensions = 1;
	  fprintf (asmfile, "@S;");
	}
      tem = TYPE_DOMAIN (type);
      if (tem == NULL)
	fprintf (asmfile, "ar%d;0;-1;",
		 TYPE_SYMTAB_ADDRESS (integer_type_node));
      else
	{
	  fprintf (asmfile, "a");
	  dbxout_range_type (tem);
	}
      CHARS (17);
      dbxout_type (TREE_TYPE (type), 0, 0);
      break;

    case RECORD_TYPE:
    case UNION_TYPE:
    case QUAL_UNION_TYPE:
      {
	int i, n_baseclasses = 0;

	if (TYPE_BINFO (type) != 0 && TYPE_BINFO_BASETYPES (type) != 0)
	  n_baseclasses = TREE_VEC_LENGTH (TYPE_BINFO_BASETYPES (type));

	/* Output a structure type.  We must use the same test here as we
	   use in the DBX_NO_XREFS case above.  */
	if ((TYPE_NAME (type) != 0
	     && ! (TREE_CODE (TYPE_NAME (type)) == TYPE_DECL
		   && DECL_IGNORED_P (TYPE_NAME (type)))
	     && !full)
	    || TYPE_SIZE (type) == 0
	    /* No way in DBX fmt to describe a variable size.  */
	    || TREE_CODE (TYPE_SIZE (type)) != INTEGER_CST)
	  {
	    /* If the type is just a cross reference, output one
	       and mark the type as partially described.
	       If it later becomes defined, we will output
	       its real definition.
	       If the type has a name, don't nest its definition within
	       another type's definition; instead, output an xref
	       and let the definition come when the name is defined.  */
	    fprintf (asmfile, (TREE_CODE (type) == RECORD_TYPE) ? "xs" : "xu");
	    CHARS (3);
#if 0 /* This assertion is legitimately false in C++.  */
	    /* We shouldn't be outputting a reference to a type before its
	       definition unless the type has a tag name.
	       A typedef name without a tag name should be impossible.  */
	    if (TREE_CODE (TYPE_NAME (type)) != IDENTIFIER_NODE)
	      abort ();
#endif
	    if (TYPE_NAME (type) != 0)
	      dbxout_type_name (type);
	    else
	      fprintf (asmfile, "$$%d", anonymous_type_number++);
	    fprintf (asmfile, ":");
	    typevec[TYPE_SYMTAB_ADDRESS (type)] = TYPE_XREF;
	    break;
	  }

	/* Identify record or union, and print its size.  */
	fprintf (asmfile, (TREE_CODE (type) == RECORD_TYPE) ? "s%d" : "u%d",
		 int_size_in_bytes (type));

	if (use_gnu_debug_info_extensions)
	  {
	    if (n_baseclasses)
	      {
		have_used_extensions = 1;
		fprintf (asmfile, "!%d,", n_baseclasses);
		CHARS (8);
	      }
	  }
	for (i = 0; i < n_baseclasses; i++)
	  {
	    tree child = TREE_VEC_ELT (BINFO_BASETYPES (TYPE_BINFO (type)), i);
	    if (use_gnu_debug_info_extensions)
	      {
		have_used_extensions = 1;
		putc (TREE_VIA_VIRTUAL (child) ? '1'
		      : '0',
		      asmfile);
		putc (TREE_VIA_PUBLIC (child) ? '2'
		      : '0',
		      asmfile);
		fprintf (asmfile, "%d,",
			 TREE_INT_CST_LOW (BINFO_OFFSET (child)) * BITS_PER_UNIT);
		CHARS (15);
		dbxout_type (BINFO_TYPE (child), 0, 0);
		putc (';', asmfile);
	      }
	    else
	      {
		/* Print out the base class information with fields
		   which have the same names at the types they hold.  */
		dbxout_type_name (BINFO_TYPE (child));
		putc (':', asmfile);
		dbxout_type (BINFO_TYPE (child), full, 0);
		fprintf (asmfile, ",%d,%d;",
			 TREE_INT_CST_LOW (BINFO_OFFSET (child)) * BITS_PER_UNIT,
			 TREE_INT_CST_LOW (DECL_SIZE (TYPE_NAME (BINFO_TYPE (child)))) * BITS_PER_UNIT);
		CHARS (20);
	      }
	  }
      }

      CHARS (11);

      /* Write out the field declarations.  */
      dbxout_type_fields (type);
      if (use_gnu_debug_info_extensions && TYPE_METHODS (type) != NULL_TREE)
	{
	  have_used_extensions = 1;
	  dbxout_type_methods (type);
	}
      putc (';', asmfile);

      if (use_gnu_debug_info_extensions && TREE_CODE (type) == RECORD_TYPE
	  /* Avoid the ~ if we don't really need it--it confuses dbx.  */
	  && TYPE_VFIELD (type))
	{
	  have_used_extensions = 1;

	  /* Tell GDB+ that it may keep reading.  */
	  putc ('~', asmfile);

	  /* We need to write out info about what field this class
	     uses as its "main" vtable pointer field, because if this
	     field is inherited from a base class, GDB cannot necessarily
	     figure out which field it's using in time.  */
	  if (TYPE_VFIELD (type))
	    {
	      putc ('%', asmfile);
	      dbxout_type (DECL_FCONTEXT (TYPE_VFIELD (type)), 0, 0);
	    }