Put scope blocks on a diet

Jan Hubicka hubicka@ucw.cz
Tue Dec 18 11:50:00 GMT 2007


> On Nov 29, 2007, Jan Hubicka <jh@suse.cz> wrote:
> 
> > We however know we can fit all the relevant information into debug
> > section of tramp3d object file and that is a lot smaller than the
> > footprints of our in-memory representation.
> 
> True.  The dwarf representation is designed to be compact, not
> efficient.  We can make that trade-off too, but I'm not sure users
> will be delighted if GCC gets even slower just in order to keep debug
> information represented internally in a more compact way.  In the end,
> any speedups out of the smaller memory working set might be lost to
> inefficiency in the internal representation.

What makes you believe that more compact representation needs necesarily
be slower?  If we just avoid keeping around all the copies of DECLs,
then we should save both memory and compilation time, since they ought
to be rather easy to be looked up in dwarf2out via ABSTRACT_ORIGIN
pointer.

Honza
> 
> -- 
> Alexandre Oliva         http://www.lsd.ic.unicamp.br/~oliva/
> FSF Latin America Board Member         http://www.fsfla.org/
> Red Hat Compiler Engineer   aoliva@{redhat.com, gcc.gnu.org}
> Free Software Evangelist  oliva@{lsd.ic.unicamp.br, gnu.org}



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