[Bug gdb/28004] DW_AT_ranges with form DW_FORM_sec_offset problem

["vries at gcc dot gnu.org" <sourceware-bugzilla@sourceware.org>]

https://sourceware.org/bugzilla/show_bug.cgi?id=28004

--- Comment #3 from Tom de Vries <vries at gcc dot gnu.org> ---
If I just start gdb with the shared lib, and print the address map I get a very
reasonable:
...
(gdb) p /x map.transitions[0]
$16 = {addr = 0x0, value = 0x0}
(gdb) p /x map.transitions[1]
$17 = {addr = 0x99040, value = 0x1b236d0}
(gdb) p /x map.transitions[2]
$19 = {addr = 0x990bb, value = 0x0}
(gdb) p /x map.transitions[3]
$20 = {addr = 0x990bc, value = 0x1b236d0}
...
with 0x99040 being the start of the text segment:
...
Disassembly of section .text:

0000000000099040 <_ZNSi8ignoreXXEl.cold>:
   99040:       48 83 e8 01             sub    $0x1,%rax
   ...
   990bb:       90                      nop

00000000000990bc <_ZNSt13basic_istreamIwSt11char_traitsIwEE8ignoreXXEl.cold>:
...

But with the reproducer, I get:
...
(gdb) p /x map.transitions[0]
$30 = {addr = 0x0, value = 0x0}
(gdb) p /x map.transitions[1]
$31 = {addr = 0x0, value = 0x2deab60}
(gdb) p /x map.transitions[2]
$32 = {addr = 0x1d, value = 0x2591ce0}
(gdb) p /x map.transitions[3]
$33 = {addr = 0x4ef, value = 0x267bf00}
(gdb) p /x map.transitions[4]
$34 = {addr = 0xf72, value = 0x26c8ee0}
(gdb) p /x map.transitions[5]
$35 = {addr = 0x15eb, value = 0x0}
(gdb) p /x map.transitions[7]
$36 = {addr = 0x990bb, value = 0x0}
(gdb) p /x map.transitions[8]
$37 = {addr = 0x990bc, value = 0x1aced00}
...

Seems to be caused by this bit in dwarf2_rnglists_process:
...
      /* A not-uncommon case of bad debug info.                                 
         Don't pollute the addrmap with bad data.  */
      if (range_beginning + baseaddr == 0
          && !per_objfile->per_bfd->has_section_at_zero)
        {
          complaint (_(".debug_rnglists entry has start address of zero"
                       " [in module %s]"), objfile_name (objfile));
          continue;
        }
...

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