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Re: [rfc] Detect dwarf address size mismatch
On Tue, Jul 17, 2007 at 03:01:04PM +0200, Mark Kettenis wrote:
>
> > @@ -6792,6 +6793,15 @@ dwarf_decode_lines (struct line_header *
> > _("mangled .debug_line section"));
> > return;
> > }
> > + /* Make sure that we parsed the extended op correctly. If e.g.
> > + we expected a different address size than the producer used,
> > + we may have read the wrong number of bytes. */
> > + if (line_ptr != extended_end)
> > + {
> > + complaint (&symfile_complaints,
> > + _("mangled .debug_line section"));
> > + return;
> > + }
> > break;
> > case DW_LNS_copy:
> > if (lh->num_file_names < file)
>
> The complaint "mangled .debug_line section" seems a bit unhelpful to
> me, especially since there are now two identical messages for what
> appears to be somewhat different conditions. Any chance of changing
> it something more distinguishable?
It was my mistake, not yours, that you didn't notice it before. It
used to say "bad address size", but Jim suggested I check all extended
ops instead of just DW_LNE_set_address. So the more specific complaint
is no longer accurate.
How about changing the first one to "unrecognized extended opcode in
.debug_line", and the second one to "mangled extended opcode in
.debug_line"?
I thought about making the unrecognized opcode case more lenient, and
using break instead of return, since we can advance line_ptr the right
amount. But I think we can't skip unrecognized line opcodes the way
we can skip unrecognized attributes; if the opcode changes the PC,
then the next advance_pc opcode will start from the wrong place, et cetera.
--
Daniel Jacobowitz
CodeSourcery