ocaml 4.01.0 → 4.02.1, binary size became larger

Question

On Ubuntu 14.04, 32 bit:

➥ cat test.ml
let () = print_endline "hello";

➥ opam switch list | grep " C "
4.01.0  C 4.01.0  Official 4.01.0 release

➥ ocamlopt test.ml 
➥ ls -l a.out
-rwxrwxr-x 1 shorrty shorrty 158569 Oct.  30 13:29 a.out

➥ opam switch 4.02.0
➥ eval `opam config env`

➥ ocamlopt test.ml 
➥ ls -l a.out
-rwxrwxr-x 1 shorrty shorrty 171122 Oct.  30 13:30 a.out

➥ opam switch 4.02.1
➥ eval `opam config env`

➥ ocamlopt test.ml 
➥ ls -l a.out
-rwxrwxr-x 1 shorrty shorrty 171196 Oct.  30 14:08 a.out

Executable size became bigger and bigger: 158569 → 171122 → 171196.

In a more complex applications I get an even greater increase in the size of the file.

Any ideas how to fix?

Update #1:

Tried strip:

➥ strip -V | head -n 1
GNU strip (GNU Binutils for Ubuntu) 2.24

➥ ls -l
-rwxrwxr-x 1 shorrty shorrty 158569 Oct.  30 15:22 a.4.01.0.out
-rwxrwxr-x 1 shorrty shorrty 117368 Oct.  30 15:26 a.4.01.0.out.stripped
-rwxrwxr-x 1 shorrty shorrty 171122 Oct.  30 15:03 a.4.02.0.out
-rwxrwxr-x 1 shorrty shorrty 127580 Oct.  30 15:26 a.4.02.0.out.stripped
-rwxrwxr-x 1 shorrty shorrty 171196 Oct.  30 15:21 a.4.02.1.out
-rwxrwxr-x 1 shorrty shorrty 127612 Oct.  30 15:26 a.4.02.1.out.stripped
-rwxrwxr-x 1 shorrty shorrty 158569 Oct.  30 15:21 a.out

It continues to grow: 117368 → 127580 → 127612

Update #2:

Tried option -compact, didn't work:

➥ opam switch 4.01.0 && eval `opam config env`

➥ ocamlopt test.ml && ls -l a.out
-rwxrwxr-x 1 shorrty shorrty 158569 Oct.  30 22:02 a.out

➥ ocamlopt -compact test.ml && ls -l a.out
-rwxrwxr-x 1 shorrty shorrty 158569 Oct.  30 22:03 a.out

➥ opam switch 4.02.1 && eval `opam config env`

➥ ocamlopt test.ml && ls -l a.out
-rwxrwxr-x 1 shorrty shorrty 171196 Oct.  30 22:05 a.out

➥ ocamlopt -compact test.ml && ls -l a.out
-rwxrwxr-x 1 shorrty shorrty 171196 Oct.  30 22:05 a.out

Tried option -inline, didn't work too:

➥ opam switch 4.01.0 && eval `opam config env`

➥ ocamlopt -inline 0 test.ml && ls -l a.out
-rwxrwxr-x 1 shorrty shorrty 158569 Oct.  30 22:07 a.out

➥ ocamlopt -inline 1 test.ml && ls -l a.out
-rwxrwxr-x 1 shorrty shorrty 158569 Oct.  30 22:07 a.out

➥ opam switch 4.02.1 && eval `opam config env`

➥ ocamlopt -inline 0 test.ml && ls -l a.out
-rwxrwxr-x 1 shorrty shorrty 171196 Oct.  30 22:08 a.out

➥ ocamlopt -inline 1 test.ml && ls -l a.out
-rwxrwxr-x 1 shorrty shorrty 171196 Oct.  30 22:09 a.out

Answer 1

Your code didn't change, but it calls the pervasives module which changed between 4.01 and 4.02.

Notably, the part about formats was changed to use GADT-based formats instead of strings. This notably made to_string, of_string and concatenation (quite) heavier.

See this discussion for more details.