ghc image size

Simon Marlow
Wed, 19 Dec 2001 09:32:55 -0000

> Mike Gunter <> writes:
> > Why is executable size a barrier?  1.64 megabytes (that's=20
> the size of
> > the executable I built with GHC most recently) of disk=20
> space costs less
> > than half a cent.
> I don't like this argument.  Can I go to a computer store, pay a cent,
> and get a hard disk with space 1.64 megabytes or more?  Until then, I
> can't believe that 1.64 megabytes of disk space costs less than half a
> cent.
> When a compiler does not perform as good as other compilers (e.g., in
> terms of generated code size), it is important to ask: Why does it
> happen? Is there anything we can do to improve it?  Being critical is
> the first step towards progress.  (Of course these questions should be
> asked in a constructive rather than whining way.)  Why would anyone
> optimize code for time --- a second of electricity and labour cost
> less than a cent...

Of course, we're always looking for ways to reduce the size of binaries.
But the situation might not be as bad as you think;  firstly, don't
forget to strip the binary if you're worried about disk space, since the
symbol table in a GHC-generated binary can be quite large (it doesn't
affect the runtime or anything else, though).

The subject of shared libraries has come up several times in the past -
take a look through the archives for some of the previous discussions.
The upshot is that shared libraries wouldn't really buy much unless you
really need to save the disk space: in all other considerations, static
linking comes out better.  Unfortunately GHC-compiled libraries are very
tightly coupled, which means it's unlikely you'd be able to swap out a
shared library for a newer version unless it was compiled with *exactly*
the same compiler and set of libraries as the old version.