gdb/dwarf2/attribute.h

   1 /* DWARF attributes
   2
   3    Copyright (C) 1994-2020 Free Software Foundation, Inc.
   4
   5    Adapted by Gary Funck (gary@intrepid.com), Intrepid Technology,
   6    Inc.  with support from Florida State University (under contract
   7    with the Ada Joint Program Office), and Silicon Graphics, Inc.
   8    Initial contribution by Brent Benson, Harris Computer Systems, Inc.,
   9    based on Fred Fish's (Cygnus Support) implementation of DWARF 1
  10    support.
  11
  12    This file is part of GDB.
  13
  14    This program is free software; you can redistribute it and/or modify
  15    it under the terms of the GNU General Public License as published by
  16    the Free Software Foundation; either version 3 of the License, or
  17    (at your option) any later version.
  18
  19    This program is distributed in the hope that it will be useful,
  20    but WITHOUT ANY WARRANTY; without even the implied warranty of
  21    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  22    GNU General Public License for more details.
  23
  24    You should have received a copy of the GNU General Public License
  25    along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
  26
  27 #ifndef GDB_DWARF2_ATTRIBUTE_H
  28 #define GDB_DWARF2_ATTRIBUTE_H
  29
  30 #include "dwarf2.h"
  31 #include "gdbtypes.h"
  32
  33 /* Blocks are a bunch of untyped bytes.  */
  34 struct dwarf_block
  35 {
  36   size_t size;
  37
  38   /* Valid only if SIZE is not zero.  */
  39   const gdb_byte *data;
  40 };
  41
  42 /* Attributes have a name and a value.  */
  43 struct attribute
  44 {
  45   /* Read the given attribute value as an address, taking the
  46      attribute's form into account.  */
  47   CORE_ADDR value_as_address () const;
  48
  49   /* If the attribute has a string form, return the string value;
  50      otherwise return NULL.  */
  51   const char *value_as_string () const;
  52
  53   /* Return non-zero if ATTR's value is a section offset --- classes
  54      lineptr, loclistptr, macptr or rangelistptr --- or zero, otherwise.
  55      You may use DW_UNSND (attr) to retrieve such offsets.
  56
  57      Section 7.5.4, "Attribute Encodings", explains that no attribute
  58      may have a value that belongs to more than one of these classes; it
  59      would be ambiguous if we did, because we use the same forms for all
  60      of them.  */
  61
  62   bool form_is_section_offset () const;
  63
  64   /* Return non-zero if ATTR's value falls in the 'constant' class, or
  65      zero otherwise.  When this function returns true, you can apply
  66      the constant_value method to it.
  67
  68      However, note that for some attributes you must check
  69      attr_form_is_section_offset before using this test.  DW_FORM_data4
  70      and DW_FORM_data8 are members of both the constant class, and of
  71      the classes that contain offsets into other debug sections
  72      (lineptr, loclistptr, macptr or rangelistptr).  The DWARF spec says
  73      that, if an attribute's can be either a constant or one of the
  74      section offset classes, DW_FORM_data4 and DW_FORM_data8 should be
  75      taken as section offsets, not constants.
  76
  77      DW_FORM_data16 is not considered as constant_value cannot handle
  78      that.  */
  79
  80   bool form_is_constant () const;
  81
  82   /* DW_ADDR is always stored already as sect_offset; despite for the forms
  83      besides DW_FORM_ref_addr it is stored as cu_offset in the DWARF file.  */
  84
  85   bool form_is_ref () const;
  86
  87   /* Check if the attribute's form is a DW_FORM_block*
  88      if so return true else false.  */
  89
  90   bool form_is_block () const;
  91
  92   /* Return DIE offset of this attribute.  Return 0 with complaint if
  93      the attribute is not of the required kind.  */
  94
  95   sect_offset get_ref_die_offset () const;
  96
  97   /* Return the constant value held by this attribute.  Return
  98      DEFAULT_VALUE if the value held by the attribute is not
  99      constant.  */
 100
 101   LONGEST constant_value (int default_value) const;
 102
 103
 104   ENUM_BITFIELD(dwarf_attribute) name : 16;
 105   ENUM_BITFIELD(dwarf_form) form : 15;
 106
 107   /* Has DW_STRING already been updated by dwarf2_canonicalize_name?  This
 108      field should be in u.str (existing only for DW_STRING) but it is kept
 109      here for better struct attribute alignment.  */
 110   unsigned int string_is_canonical : 1;
 111
 112   union
 113     {
 114       const char *str;
 115       struct dwarf_block *blk;
 116       ULONGEST unsnd;
 117       LONGEST snd;
 118       CORE_ADDR addr;
 119       ULONGEST signature;
 120     }
 121   u;
 122 };
 123
 124 /* Get at parts of an attribute structure.  */
 125
 126 #define DW_STRING(attr)    ((attr)->u.str)
 127 #define DW_STRING_IS_CANONICAL(attr) ((attr)->string_is_canonical)
 128 #define DW_UNSND(attr)     ((attr)->u.unsnd)
 129 #define DW_BLOCK(attr)     ((attr)->u.blk)
 130 #define DW_SND(attr)       ((attr)->u.snd)
 131 #define DW_ADDR(attr)      ((attr)->u.addr)
 132 #define DW_SIGNATURE(attr) ((attr)->u.signature)
 133
 134 #endif /* GDB_DWARF2_ATTRIBUTE_H */