I'm trying to compile OCaml for arm64/aarch64.  I'm currently
trying the trunk branch from:

https://github.com/ocaml/ocaml

which should be identical to SVN.  It requires a trivial patch which
is attached.

I'm using qemu as an arm64 userspace emulator, with Fedora Rawhide:

http://rwmj.wordpress.com/2013/12/22/how-to-run-aarch64-binaries-on-an-x86-64-host-using-qemu-userspace-emulation/#content

Anyway, it hangs, consistently as soon as it tries to run any
ocamlopt-compiled program.  During the compile, the first hang is
here:

../../ocamlcomp.sh -c -w +33..39 -warn-error A -g -nolabels unix.mli

[which runs the just-compiled ocamlc.opt], but even a trivial test
program hangs:

$ echo 'print_endline "hello, world"' > test.ml
$ ./boot/ocamlrun ./ocamlopt -I stdlib stdlib.cmxa test.ml -o test
$ ./test
[hangs here]

Disassembly shows this really is an aarch64 native binary.

Unfortunately because of the technique I'm using (qemu-arm64) I cannot
use gdb or strace to look at where it is hanging, although I am
reasonably sure that it's not hanging *because* of qemu -- at least,
I've been able to compile and run masses of software using gcc under
the same conditions.

Has anyone seen this or have any other ideas?

Am I using the right branch for arm64 work?

Rich.

-- 
Richard Jones
Red Hat