Re: Skipping over trampolines/stubs

[Jonas Maebe <jonas.maebe@elis.ugent.be>]

On 01 Apr 2009, at 22:19, Daniel Jacobowitz wrote:

> On Wed, Apr 01, 2009 at 10:15:33PM +0200, Jonas Maebe wrote:
>> Which brings me to the next point: how does one go about  
>> "allocating" a
>> new DW_AT_calling_convention value in the DW_CC_lo_user ..  
>> DW_CC_hi_user
>> range? At first sight, there is only one such value currently in  
>> public
>> use (DW_CC_GNU_renesas_sh). Can I just take 0x41 for
>> DW_CC_BORLAND_fastcall_i386? And should I then submit this constant  
>> for
>> inclusion in binutils first?
>
> I don't know - might want to raise this on the DWARF discussion list
> (see dwarfstd.org).

In case anyone else would ever wonder about this, below is the first  
answer I received (since the archives for the dwarf-discuss list are  
limited to subscribers). It appears that it's entirely up to binutils/ 
gdb maintainers in this case.


Jonas

	From: 	roland at redhat.com
	Subject: Re: [Dwarf-Discuss] Reserving a new DW_AT_calling_convention  
value
	Date: 	Wed 1 Apr 2009 23:26:58 GMT+02:00
	To: 	jonas.maebe@elis.ugent.be
	Cc: 	dwarf-discuss@lists.dwarfstd.org

> I would like to use a new DW_AT_calling_convention attribute value in
> the range DW_CC_lo_user .. DW_CC_hi_user. As far as I can tell, the
> only one currently in (public) use is DW_CC_GNU_renesas_sh (= 0x40).
> My question is: how does one go about reserving/obtaining such a
> number? Do you just take the next one that appears to be available and
> submit patches using this value to binutils (for elf/dwarf.h) and gdb?
> (and possibly dwarflib, and maybe others)

In the lo_user..hi_user range, it is up to each "vendor" to decide the
conventions for using that range.  The different implementors  
("vendors")
try to stay aware of each other's uses, but "vendor-specific extensions"
means exactly that there is not any shared formal management of that  
space.

The DWARF committee decides on the common uses in the <lo_user range.
It's entirely reasonable to propose new values in the common range.

For ELF and DWARF "vendor" stuff in the GNU and Linux world, the  
convention
is consensus of the binutils, elfutils, and (when relevant) GCC  
maintainers.
If you propose your patches for binutils/gdb and gcc in the normal  
ways on
those mailing lists, that will do it.


Thanks,
Roland