Adding new dwarf encoding formats for complex integers

Adding new dwarf encoding formats for complex integers

[Doug Kwan (關振德)]

Hi,

    I am working on the gcc LTO project and I found that gcc does not
generate sufficient debugging information for complex integer types.
Currently gcc uses encoding DW_ATE_lo_user ( 0x80) for complex integer
types but that 1) clashes with an HP extension and 2) does not
distinguish between complex signed integer and complex unsigned
integer types.  I'm thinking about adding DW_ATE_GNU_complex_signed
(0x87) and DW_ATE_GNU_complex_unsigned (0x88) encoding formats.

  Is there anything I need to do in addition to changing gcc? Are
there people I should talk to? And what documentation should be
updated? Currently gdb (I checked 6.7) does not support complex
integer properly. So it needs to be changed anyway.

-Doug

Re: Adding new dwarf encoding formats for complex integers

[Daniel Jacobowitz]

On Fri, Dec 14, 2007 at 02:30:36PM -0800, Doug Kwan (關振德) wrote:
>   Is there anything I need to do in addition to changing gcc? Are
> there people I should talk to? And what documentation should be
> updated? Currently gdb (I checked 6.7) does not support complex
> integer properly. So it needs to be changed anyway.

The DWARF standard has its own mailing list and working group.  I
recommend contacting them first, to see if there's interest in a
general definition.

If you just want to add it to the GNU tools, then lo_user seems like
the best place to put it - it's a vendor extension - so I don't
see the problem.

-- 
Daniel Jacobowitz
CodeSourcery

Re: Adding new dwarf encoding formats for complex integers

[Doug Kwan (關振德)]

The new encoding format I am proposing fall between DW_ATE_lo_user and
DW_ATE_hi_user. So they are vendor extensions.  Currently gcc uses
DW_ATE_lo_user, which collides with an HP vendor extension.

-Doug

2007/12/14, Daniel Jacobowitz <drow@false.org>:
> On Fri, Dec 14, 2007 at 02:30:36PM -0800, Doug Kwan (關振德) wrote:
> >   Is there anything I need to do in addition to changing gcc? Are
> > there people I should talk to? And what documentation should be
> > updated? Currently gdb (I checked 6.7) does not support complex
> > integer properly. So it needs to be changed anyway.
>
> The DWARF standard has its own mailing list and working group.  I
> recommend contacting them first, to see if there's interest in a
> general definition.
>
> If you just want to add it to the GNU tools, then lo_user seems like
> the best place to put it - it's a vendor extension - so I don't
> see the problem.
>
> --
> Daniel Jacobowitz
> CodeSourcery
>

Re: Adding new dwarf encoding formats for complex integers

[Daniel Jacobowitz]

On Fri, Dec 14, 2007 at 02:47:02PM -0800, Doug Kwan (關振德) wrote:
> The new encoding format I am proposing fall between DW_ATE_lo_user and
> DW_ATE_hi_user. So they are vendor extensions.  Currently gcc uses
> DW_ATE_lo_user, which collides with an HP vendor extension.

If we already have one vendor extension, why switch?  The vendor
extensions conflict with other vendors... that's by definition.

-- 
Daniel Jacobowitz
CodeSourcery