Re: RFC: Change in dwarf2dbg using sizeof_offset

[Kai Tietz <Kai dot Tietz at onevision dot com>]

Hello Alan,

Alan Modra <amodra@bigpond.net.au> wrote on 30.07.2008 10:29:23:

> On Tue, Jul 29, 2008 at 12:27:30PM +0200, Kai Tietz wrote:
> > Hi,
> > 
> > has I noticed uses dwarf2dbg.c for TC_DWARF2_EMIT_OFFSET in some 
places 
> > the sizeof 4 bytes instead of sizeof_offset. This is a major problem 
for 
> > the w64 target, because section relative relocation have to be 64-bit 
> > wide, and there is no useful 32-bit relocation, which could handle 
this. I 
> > would suggest to change those dw2 types, like DW_AT_stmt_list and the 
> > arange to use sizeof_offset instead.
> > Is this already a bug, or is this a major change? I saw already 
comments 
> > about this issue in source code, too.
> 
> I don't think either of these are bugs, but it is a little strange
> that we don't use the 64-bit offsets for 64-bit targets since that
> means we can't have a .debug_info section larger than 4G.
> 
> Now, if you change the DW_AT_stmt_list TC_DWARF2_EMIT_OFFSET then of
> course you need to change out_debug_abbrev to emit the correct DW_FORM
> for it.  That change should be painless, I think.
> 
> If you change the .debug_aranges TC_DWARF2_EMIT_OFFSET, then you need
> to also output a 64-bit dwarf section length (0xffffffff followed by a
> 64-bit length) for .debug_aranges, to notify consumers that the
> section is 64-bit dwarf.  The current 32-bit section length used in
> .debug_aranges says that .debug_aranges is always 32-bit dwarf, even
> on a 64-bit target.
> 
> Does anyone see a reason why we shouldn't make these changes?

At the moment I do not warn about .secrel32 in 64-bit and do not disabled 
it, because gcc tests for secrel32 to enable dw2 for mingw at the moment.

ChangeLog for gas

2008-07-30  Kai Tietz  <kai.tietz@onevision.com>

        * config/tc-i386.c (md_pseudo_table): Add secrel64 symbol.
        (pe_directive_secrel): Make use of argument to verify secrel size.
        * dwarf2dbg.c (out_debug_aranges): Adjust to use 64-bit frame and 
sizeof_offset.
        (out_debug_abbrev): DW_AT_stmt_list use 64-bit dw2 frame.
        (out_debug_info): Use sizeof_offset for TC_DWARF2_EMIT_OFFSET.

Is this patch ok for mainline?

Regards,
 i.A. Kai Tietz



|  (\_/)  This is Bunny. Copy and paste Bunny
| (='.'=) into your signature to help him gain
| (")_(") world domination.

Attachment: gas_secrel64.txt
Description: Text document