[Bug symtab/34464] GCC binaries in -fPIE -ffunction-sections --gc-sections have DWARF subprograms overlapping main, breaking function resolution

https://sourceware.org/bugzilla/show_bug.cgi?id=3D34464

--- Comment #5 from Tom Tromey <tromey at sourceware dot org> ---
(In reply to nyanpasu64 from comment #3)

> Bug 13415 references a gdb comment saying that gdb/dwarf2/read.c
> #lnp_state_machine::check_line_address already checks for GC'd functions =
at
> 0, -1, or -2. Apparently this check isn't working here?

I suspect the reason is that this ELF has a section at zero:

$ readelf -WS sys-ftpd.elf
...
  [ 1] .text             PROGBITS        0000000000000000 010000 032af0 00 =
 AX=20
0   0 64


This means that a symbol with PC=3D0 might be valid, so gdb's DWARF reader
skips the GC function stuff in this case.  E.g.

  if ((bfd_section_flags (sectp) & (SEC_LOAD | SEC_ALLOC))
      && bfd_section_vma (sectp) =3D=3D 0)
    this->has_section_at_zero =3D true;

Though I see that lnp_state_machine::check_line_address doesn't actually
check this flag... but other things do.

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