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Re: change #9754: 5 x slowdown for perl -d

From:
Dave Mitchell
Date:
January 20, 2003 11:10
Subject:
Re: change #9754: 5 x slowdown for perl -d
Message ID:
20030120190701.B28899@fdgroup.com
On Mon, Jan 20, 2003 at 06:51:02PM +0000, Dave Mitchell wrote:
> I think I now know what's happening (at least mostly).
> 
> perl5db.pl uses the magic typeglob PL_DBline (aka DB::dbline) to
> set breakpoints.
> 
> The magic for this typeglob calls Perl_magic_setdbline, which
> sets op_private of the COP associated with the breakpoint to 1 or 0
> as appropriate.
> 
> Im not sure where the value 2 comes into play, though.

Further thoughts - I'm guessing that the 0x2 was just HINT_STRICT_REFS
leaking from PL_hints and that the debugging only uses 1 bit of
op_private.

If this is the case, we could steal the unused 0x10 bit of HINTS and
use that to do the signalling, by appropriately modifying pp_dbstate() and
Perl_magic_setdbline().

How does that sound as a plan?

-- 
"Strange women lying in ponds distributing swords is no basis for a system
of government. Supreme executive power derives from a mandate from the
masses, not from some farcical aquatic ceremony."
Dennis - Monty Python and the Holy Grail.

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