1/* Enumerate the PC ranges covered by a DIE.
2   Copyright (C) 2005, 2007 Red Hat, Inc.
3   This file is part of Red Hat elfutils.
4
5   Red Hat elfutils is free software; you can redistribute it and/or modify
6   it under the terms of the GNU General Public License as published by the
7   Free Software Foundation; version 2 of the License.
8
9   Red Hat elfutils is distributed in the hope that it will be useful, but
10   WITHOUT ANY WARRANTY; without even the implied warranty of
11   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
12   General Public License for more details.
13
14   You should have received a copy of the GNU General Public License along
15   with Red Hat elfutils; if not, write to the Free Software Foundation,
16   Inc., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301 USA.
17
18   In addition, as a special exception, Red Hat, Inc. gives You the
19   additional right to link the code of Red Hat elfutils with code licensed
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25   those well defined interfaces identified in the file named EXCEPTION
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36   covered by this exception.  If you modify this file, you may extend this
37   exception to your version of the file, but you are not obligated to do
38   so.  If you do not wish to provide this exception without modification,
39   you must delete this exception statement from your version and license
40   this file solely under the GPL without exception.
41
42   Red Hat elfutils is an included package of the Open Invention Network.
43   An included package of the Open Invention Network is a package for which
44   Open Invention Network licensees cross-license their patents.  No patent
45   license is granted, either expressly or impliedly, by designation as an
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48   <http://www.openinventionnetwork.com>.  */
49
50#ifdef HAVE_CONFIG_H
51# include <config.h>
52#endif
53
54#include "libdwP.h"
55#include <dwarf.h>
56#include <assert.h>
57
58
59ptrdiff_t
60dwarf_ranges (Dwarf_Die *die, ptrdiff_t offset, Dwarf_Addr *basep,
61	      Dwarf_Addr *startp, Dwarf_Addr *endp)
62{
63  if (die == NULL)
64    return -1;
65
66  if (offset == 0
67      /* Usually there is a single contiguous range.  */
68      && INTUSE(dwarf_highpc) (die, endp) == 0
69      && INTUSE(dwarf_lowpc) (die, startp) == 0)
70    /* A offset into .debug_ranges will never be 1, it must be at least a
71       multiple of 4.  So we can return 1 as a special case value to mark
72       there are no ranges to look for on the next call.  */
73    return 1;
74
75  if (offset == 1)
76    return 0;
77
78  /* We have to look for a noncontiguous range.  */
79
80  const Elf_Data *d = die->cu->dbg->sectiondata[IDX_debug_ranges];
81  if (d == NULL)
82    {
83      __libdw_seterrno (DWARF_E_NO_DEBUG_RANGES);
84      return -1;
85    }
86
87  if (offset == 0)
88    {
89      Dwarf_Attribute attr_mem;
90      Dwarf_Attribute *attr = INTUSE(dwarf_attr) (die, DW_AT_ranges,
91						  &attr_mem);
92      if (attr == NULL)
93	return -1;
94
95      /* Must have the form data4 or data8 which act as an offset.  */
96      Dwarf_Word start_offset;
97      if (INTUSE(dwarf_formudata) (attr, &start_offset) != 0)
98	return -1;
99
100      offset = start_offset;
101      assert ((Dwarf_Word) offset == start_offset);
102
103      /* Fetch the CU's base address.  */
104      Dwarf_Die cudie = CUDIE (attr->cu);
105
106      /* Find the base address of the compilation unit.  It will
107	 normally be specified by DW_AT_low_pc.  In DWARF-3 draft 4,
108	 the base address could be overridden by DW_AT_entry_pc.  It's
109	 been removed, but GCC emits DW_AT_entry_pc and not DW_AT_lowpc
110	 for compilation units with discontinuous ranges.  */
111      if (unlikely (INTUSE(dwarf_lowpc) (&cudie, basep) != 0)
112	  && INTUSE(dwarf_formaddr) (INTUSE(dwarf_attr) (&cudie,
113							 DW_AT_entry_pc,
114							 &attr_mem),
115				     basep) != 0)
116	{
117	  if (INTUSE(dwarf_errno) () == 0)
118	    {
119	    invalid:
120	      __libdw_seterrno (DWARF_E_INVALID_DWARF);
121	    }
122	  return -1;
123	}
124    }
125  else if (offset < 0 || (size_t) offset >= d->d_size)
126    {
127      __libdw_seterrno (DWARF_E_INVALID_OFFSET);
128      return -1l;
129    }
130
131  unsigned char *readp = d->d_buf + offset;
132
133 next:
134  if ((unsigned char *) d->d_buf + d->d_size - readp
135      < die->cu->address_size * 2)
136    goto invalid;
137
138  Dwarf_Addr begin;
139  Dwarf_Addr end;
140  if (die->cu->address_size == 8)
141    {
142      begin = read_8ubyte_unaligned_inc (die->cu->dbg, readp);
143      end = read_8ubyte_unaligned_inc (die->cu->dbg, readp);
144      if (begin == (uint64_t) -1l) /* Base address entry.  */
145	{
146	  *basep = end;
147	  goto next;
148	}
149    }
150  else
151    {
152      begin = read_4ubyte_unaligned_inc (die->cu->dbg, readp);
153      end = read_4ubyte_unaligned_inc (die->cu->dbg, readp);
154      if (begin == (uint32_t) -1) /* Base address entry.  */
155	{
156	  *basep = end;
157	  goto next;
158	}
159    }
160
161  if (begin == 0 && end == 0) /* End of list entry.  */
162    return 0;
163
164  /* We have an address range entry.  */
165  *startp = *basep + begin;
166  *endp = *basep + end;
167  return readp - (unsigned char *) d->d_buf;
168}
169INTDEF (dwarf_ranges)
170