[MLton] Embedded MLton
fluet at tti-c.org
Tue Aug 19 17:04:58 PDT 2008
On Sun, 20 Jul 2008, Wesley W. Terpstra wrote:
> What options can I use to convince MLton to output small executables?
> Ideally I'd like to get hello-world to below 100k. With static linking of
> all but libc/m it is currently 260k.
You can try adjusting the various inlining and code-duplication
threshholds. But, that often as much hurts code size, because there is a
win in trimming unused code paths after inlining.
Also, in a hello-world program, the majority executable will come from the
libraries (libmlton and libgmp), not from the individual program. For
example, on amd64-linux (with libgmp shared):
[fluet at shadow temp]$ cat z.sml
val () = print "Hello world!\n"
[fluet at shadow temp]$ mlton -keep o z.sml
[fluet at shadow temp]$ size z.0.o z.1.o z
text data bss dec hex filename
2465 6136 2 8603 219b z.0.o
33411 19 0 33430 8296 z.1.o
122157 7296 10208 139661 2218d z
So approx 66% comes from libmlton.a. The garbage collector probably
contributes the most from libmlton.a to the executable.
> I already tried removing all unused symbols from libgmp.a and libmlton.a.
> The benefit was not spectacular, only 40k. libgmp.a already includes each
> function in a separate file so static linking drops all the unneeded
> methods. Similarly, most of the basis wrapper functions are dropped.
Right. You are left with the garbage collector. There are some features
that you might be willing to disable for an embedded system (for example,
the hash-consing collection is rarely used), but you would need to build a
customized libmlton.a for that.
More information about the MLton