Re: GCC 4.1: Buildable on GHz machines only?

[Andrew Haley <aph at redhat dot com>]

Ian Lance Taylor writes:
 > Andrew Haley <aph@redhat.com> writes:
 > 
 > >  > >> OK, I know nothing about libtool so this might not be possible, but
 > >  > >> IMO the easiest way of making a dramatic difference is to cease to
 > >  > >> compile every file twice, once with PIC and once without.  There would
 > >  > >> be a small performance regression for statically linked Java apps, but
 > >  > >> in practice Java is very hard to use with static linkage.
 > >  > >
 > >  > > Try putting
 > >  > >
 > >  > > enable_shared=no
 > >  > >
 > >  > > in configure.ac somewhere before AC_PROG_LIBTOOL.
 > >  > 
 > >  > I think you rather want AC_DISABLE_STATIC.
 > > 
 > > Won't that disable static libraries?  I don't want to do that.
 > 
 > Sorry, my misunderstanding.
 > 
 > I don't know of a way to tell libtool to not do duplicate compiles.
 > You can use -prefer-pic, but at least from looking at the script it
 > will still compile twice, albeit with -fPIC both times.
 > 
 > Incidentally, at least on my system I don't think this will make a
 > dramatic difference.  The incredibly slow parts of building libjava
 > all seem to have to do with building the .a and .so files, both of
 > which tend to cause my system to start swapping.

IME the biggest thing there is the libtool shell script.  

 > While it would obviously help to not build the objects twice, that
 > doesn't seem to be the major time sink, at least not for me.

That's not the problem I have: the link is slow, but it's not the
dominant thing.  Maybe it depends how much RAM you have?  I have 1 Gbyte.

Andrew.