Create dwarf2/attribute.[ch]

[deliverable/binutils-gdb.git] / gdb / dwarf2 / attribute.h

/* DWARF attributes

   Copyright (C) 1994-2020 Free Software Foundation, Inc.

   Adapted by Gary Funck (gary@intrepid.com), Intrepid Technology,
   Inc.  with support from Florida State University (under contract
   with the Ada Joint Program Office), and Silicon Graphics, Inc.
   Initial contribution by Brent Benson, Harris Computer Systems, Inc.,
   based on Fred Fish's (Cygnus Support) implementation of DWARF 1
   support.

   This file is part of GDB.

   This program 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 of the License, or
   (at your option) any later version.

   This program 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 this program.  If not, see <http://www.gnu.org/licenses/>.  */

#ifndef GDB_DWARF2_ATTRIBUTE_H
#define GDB_DWARF2_ATTRIBUTE_H

#include "dwarf2.h"

/* Blocks are a bunch of untyped bytes.  */
struct dwarf_block
{
  size_t size;

  /* Valid only if SIZE is not zero.  */
  const gdb_byte *data;
};

/* Attributes have a name and a value.  */
struct attribute
{
  ENUM_BITFIELD(dwarf_attribute) name : 16;
  ENUM_BITFIELD(dwarf_form) form : 15;

  /* Has DW_STRING already been updated by dwarf2_canonicalize_name?  This
     field should be in u.str (existing only for DW_STRING) but it is kept
     here for better struct attribute alignment.  */
  unsigned int string_is_canonical : 1;

  union
    {
      const char *str;
      struct dwarf_block *blk;
      ULONGEST unsnd;
      LONGEST snd;
      CORE_ADDR addr;
      ULONGEST signature;
    }
  u;
};

/* Get at parts of an attribute structure.  */

#define DW_STRING(attr)    ((attr)->u.str)
#define DW_STRING_IS_CANONICAL(attr) ((attr)->string_is_canonical)
#define DW_UNSND(attr)     ((attr)->u.unsnd)
#define DW_BLOCK(attr)     ((attr)->u.blk)
#define DW_SND(attr)       ((attr)->u.snd)
#define DW_ADDR(attr)	   ((attr)->u.addr)
#define DW_SIGNATURE(attr) ((attr)->u.signature)

/* Read the given attribute value as an address, taking the attribute's
   form into account.  */

extern CORE_ADDR attr_value_as_address (struct attribute *attr);

/* Check if the attribute's form is a DW_FORM_block*
   if so return true else false.  */

extern int attr_form_is_block (const struct attribute *attr);

/* Return non-zero if ATTR's value is a section offset --- classes
   lineptr, loclistptr, macptr or rangelistptr --- or zero, otherwise.
   You may use DW_UNSND (attr) to retrieve such offsets.

   Section 7.5.4, "Attribute Encodings", explains that no attribute
   may have a value that belongs to more than one of these classes; it
   would be ambiguous if we did, because we use the same forms for all
   of them.  */

extern int attr_form_is_section_offset (const struct attribute *attr);

/* Return non-zero if ATTR's value falls in the 'constant' class, or
   zero otherwise.  When this function returns true, you can apply
   dwarf2_get_attr_constant_value to it.

   However, note that for some attributes you must check
   attr_form_is_section_offset before using this test.  DW_FORM_data4
   and DW_FORM_data8 are members of both the constant class, and of
   the classes that contain offsets into other debug sections
   (lineptr, loclistptr, macptr or rangelistptr).  The DWARF spec says
   that, if an attribute's can be either a constant or one of the
   section offset classes, DW_FORM_data4 and DW_FORM_data8 should be
   taken as section offsets, not constants.

   DW_FORM_data16 is not considered as dwarf2_get_attr_constant_value
   cannot handle that.  */

extern int attr_form_is_constant (const struct attribute *attr);

/* DW_ADDR is always stored already as sect_offset; despite for the forms
   besides DW_FORM_ref_addr it is stored as cu_offset in the DWARF file.  */

extern int attr_form_is_ref (const struct attribute *attr);

#endif /* GDB_DWARF2_ATTRIBUTE_H */