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      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
     20    under any Open Source Initiative certified open source license
     21    (http://www.opensource.org/licenses/index.php) which requires the
     22    distribution of source code with any binary distribution and to
     23    distribute linked combinations of the two.  Non-GPL Code permitted under
     24    this exception must only link to the code of Red Hat elfutils through
     25    those well defined interfaces identified in the file named EXCEPTION
     26    found in the source code files (the "Approved Interfaces").  The files
     27    of Non-GPL Code may instantiate templates or use macros or inline
     28    functions from the Approved Interfaces without causing the resulting
     29    work to be covered by the GNU General Public License.  Only Red Hat,
     30    Inc. may make changes or additions to the list of Approved Interfaces.
     31    Red Hat's grant of this exception is conditioned upon your not adding
     32    any new exceptions.  If you wish to add a new Approved Interface or
     33    exception, please contact Red Hat.  You must obey the GNU General Public
     34    License in all respects for all of the Red Hat elfutils code and other
     35    code used in conjunction with Red Hat elfutils except the Non-GPL Code
     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
     46    included package.  Should you wish to participate in the Open Invention
     47    Network licensing program, please visit www.openinventionnetwork.com
     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 
     59 ptrdiff_t
     60 dwarf_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 }
    169 INTDEF (dwarf_ranges)
    170