Re: Reducing debug info for C++ ctors/dtors

[Jason Molenda <jason-gcclist@molenda.com>]

On Mon, Jul 11, 2005 at 08:56:36PM -0400, Daniel Jacobowitz wrote:

> > However, it is good enough to have
> > 
> >         .stabs "Base1:Tt(0,41)=s4x:(0,9),0,32;getx::(0,44)=#(0,41), 
> > (0,9),(0,43)=*(0,41),(0,36);:_ZN5Base14getxEv;2A.;;",128,0,1,0

> Eh, no.  You have just lost any information about what constructors
> were declared in the class.  

Yeah, Devang didn't present what we're doing here on the debug side
too well.  We're giving up a bit of information from within gdb --
it won't know what constructors and destructors a class has defined
-- for a large savings in debug info (this can be over 20% of an
application's debug info when lots of templates are in heavy use).

Because the FUN stabs are still present, gdb knows about the
constructors; it can step into them, it can set breakpoints on them.

For most developers, this isn't a worthwhile tradeoff, but for a
certain class of appliations the stabs debug info is enormous and
this helps to ameloriate that by giving up a small bit of gdb
functionality.  This won't be enabled by default even within Apple,
but it is a useful option to have available.


Jason