LCOV - code coverage report
Current view: top level - libdw - dwarf_ranges.c (source / functions) Hit Total Coverage
Test: lcov.out Lines: 42 49 85.7 %
Date: 2017-01-05 09:15:16 Functions: 2 2 100.0 %
Legend: Lines: hit not hit

          Line data    Source code
       1             : /* Enumerate the PC ranges covered by a DIE.
       2             :    Copyright (C) 2005, 2007, 2009 Red Hat, Inc.
       3             :    This file is part of elfutils.
       4             : 
       5             :    This file is free software; you can redistribute it and/or modify
       6             :    it under the terms of either
       7             : 
       8             :      * the GNU Lesser General Public License as published by the Free
       9             :        Software Foundation; either version 3 of the License, or (at
      10             :        your option) any later version
      11             : 
      12             :    or
      13             : 
      14             :      * the GNU General Public License as published by the Free
      15             :        Software Foundation; either version 2 of the License, or (at
      16             :        your option) any later version
      17             : 
      18             :    or both in parallel, as here.
      19             : 
      20             :    elfutils is distributed in the hope that it will be useful, but
      21             :    WITHOUT ANY WARRANTY; without even the implied warranty of
      22             :    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
      23             :    General Public License for more details.
      24             : 
      25             :    You should have received copies of the GNU General Public License and
      26             :    the GNU Lesser General Public License along with this program.  If
      27             :    not, see <http://www.gnu.org/licenses/>.  */
      28             : 
      29             : #ifdef HAVE_CONFIG_H
      30             : # include <config.h>
      31             : #endif
      32             : 
      33             : #include "libdwP.h"
      34             : #include <dwarf.h>
      35             : #include <assert.h>
      36             : 
      37             : /* Read up begin/end pair and increment read pointer.
      38             :     - If it's normal range record, set up `*beginp' and `*endp' and return 0.
      39             :     - If it's base address selection record, set up `*basep' and return 1.
      40             :     - If it's end of rangelist, don't set anything and return 2
      41             :     - If an error occurs, don't set anything and return -1.  */
      42             : internal_function int
      43         123 : __libdw_read_begin_end_pair_inc (Dwarf *dbg, int sec_index,
      44             :                                  unsigned char **addrp, int width,
      45             :                                  Dwarf_Addr *beginp, Dwarf_Addr *endp,
      46             :                                  Dwarf_Addr *basep)
      47             : {
      48         123 :   Dwarf_Addr escape = (width == 8 ? (Elf64_Addr) -1
      49         123 :                        : (Elf64_Addr) (Elf32_Addr) -1);
      50             :   Dwarf_Addr begin;
      51             :   Dwarf_Addr end;
      52             : 
      53         123 :   unsigned char *addr = *addrp;
      54         123 :   bool begin_relocated = READ_AND_RELOCATE (__libdw_relocate_address, begin);
      55         123 :   bool end_relocated = READ_AND_RELOCATE (__libdw_relocate_address, end);
      56         123 :   *addrp = addr;
      57             : 
      58             :   /* Unrelocated escape for begin means base address selection.  */
      59         123 :   if (begin == escape && !begin_relocated)
      60             :     {
      61           1 :       if (unlikely (end == escape))
      62             :         {
      63           0 :           __libdw_seterrno (DWARF_E_INVALID_DWARF);
      64           0 :           return -1;
      65             :         }
      66             : 
      67           1 :       if (basep != NULL)
      68           1 :         *basep = end;
      69             :       return 1;
      70             :     }
      71             : 
      72             :   /* Unrelocated pair of zeroes means end of range list.  */
      73         122 :   if (begin == 0 && end == 0 && !begin_relocated && !end_relocated)
      74             :     return 2;
      75             : 
      76             :   /* Don't check for begin_relocated == end_relocated.  Serve the data
      77             :      to the client even though it may be buggy.  */
      78         114 :   *beginp = begin;
      79         114 :   *endp = end;
      80             : 
      81         114 :   return 0;
      82             : }
      83             : 
      84             : ptrdiff_t
      85        1877 : dwarf_ranges (Dwarf_Die *die, ptrdiff_t offset, Dwarf_Addr *basep,
      86             :               Dwarf_Addr *startp, Dwarf_Addr *endp)
      87             : {
      88        1877 :   if (die == NULL)
      89             :     return -1;
      90             : 
      91        1877 :   if (offset == 0
      92             :       /* Usually there is a single contiguous range.  */
      93        1431 :       && INTUSE(dwarf_highpc) (die, endp) == 0
      94         786 :       && INTUSE(dwarf_lowpc) (die, startp) == 0)
      95             :     /* A offset into .debug_ranges will never be 1, it must be at least a
      96             :        multiple of 4.  So we can return 1 as a special case value to mark
      97             :        there are no ranges to look for on the next call.  */
      98             :     return 1;
      99             : 
     100        1091 :   if (offset == 1)
     101             :     return 0;
     102             : 
     103             :   /* We have to look for a noncontiguous range.  */
     104             : 
     105         653 :   const Elf_Data *d = die->cu->dbg->sectiondata[IDX_debug_ranges];
     106         653 :   if (d == NULL && offset != 0)
     107             :     {
     108           0 :       __libdw_seterrno (DWARF_E_NO_DEBUG_RANGES);
     109           0 :       return -1;
     110             :     }
     111             : 
     112             :   unsigned char *readp;
     113             :   unsigned char *readendp;
     114         653 :   if (offset == 0)
     115             :     {
     116             :       Dwarf_Attribute attr_mem;
     117         645 :       Dwarf_Attribute *attr = INTUSE(dwarf_attr) (die, DW_AT_ranges,
     118             :                                                   &attr_mem);
     119         645 :       if (attr == NULL)
     120             :         /* No PC attributes in this DIE at all, so an empty range list.  */
     121         638 :         return 0;
     122             : 
     123             :       Dwarf_Word start_offset;
     124           7 :       if ((readp = __libdw_formptr (attr, IDX_debug_ranges,
     125             :                                     DWARF_E_NO_DEBUG_RANGES,
     126             :                                     &readendp, &start_offset)) == NULL)
     127             :         return -1;
     128             : 
     129           7 :       offset = start_offset;
     130             :       assert ((Dwarf_Word) offset == start_offset);
     131             : 
     132             :       /* Fetch the CU's base address.  */
     133          14 :       Dwarf_Die cudie = CUDIE (attr->cu);
     134             : 
     135             :       /* Find the base address of the compilation unit.  It will
     136             :          normally be specified by DW_AT_low_pc.  In DWARF-3 draft 4,
     137             :          the base address could be overridden by DW_AT_entry_pc.  It's
     138             :          been removed, but GCC emits DW_AT_entry_pc and not DW_AT_lowpc
     139             :          for compilation units with discontinuous ranges.  */
     140           7 :       if (unlikely (INTUSE(dwarf_lowpc) (&cudie, basep) != 0)
     141           1 :           && INTUSE(dwarf_formaddr) (INTUSE(dwarf_attr) (&cudie,
     142             :                                                          DW_AT_entry_pc,
     143             :                                                          &attr_mem),
     144             :                                      basep) != 0)
     145           1 :         *basep = (Dwarf_Addr) -1;
     146             :     }
     147             :   else
     148             :     {
     149           8 :       if (__libdw_offset_in_section (die->cu->dbg,
     150             :                                      IDX_debug_ranges, offset, 1))
     151             :         return -1l;
     152             : 
     153           8 :       readp = d->d_buf + offset;
     154           8 :       readendp = d->d_buf + d->d_size;
     155             :     }
     156             : 
     157             :  next:
     158          16 :   if (readendp - readp < die->cu->address_size * 2)
     159             :     goto invalid;
     160             : 
     161             :   Dwarf_Addr begin;
     162             :   Dwarf_Addr end;
     163             : 
     164          16 :   switch (__libdw_read_begin_end_pair_inc (die->cu->dbg, IDX_debug_ranges,
     165             :                                            &readp, die->cu->address_size,
     166             :                                            &begin, &end, basep))
     167             :     {
     168             :     case 0:
     169             :       break;
     170             :     case 1:
     171             :       goto next;
     172             :     case 2:
     173             :       return 0;
     174             :     default:
     175           0 :       return -1l;
     176             :     }
     177             : 
     178             :   /* We have an address range entry.  Check that we have a base.  */
     179          14 :   if (*basep == (Dwarf_Addr) -1)
     180             :     {
     181           0 :       if (INTUSE(dwarf_errno) () == 0)
     182             :         {
     183             :         invalid:
     184           0 :           __libdw_seterrno (DWARF_E_INVALID_DWARF);
     185             :         }
     186             :       return -1;
     187             :     }
     188             : 
     189          14 :   *startp = *basep + begin;
     190          14 :   *endp = *basep + end;
     191          14 :   return readp - (unsigned char *) d->d_buf;
     192             : }
     193             : INTDEF (dwarf_ranges)

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