Bootstrap on OpenBSD?

[hosewiejacke]

I'd like to try MLton on OpenBSD.

However, in order to compile mlton I need a compiled mlton :)
Sourceforge has only binaries for Darwin and Linux.

Any idea how to proceed?

[AlexanderAA]

A working but unfinished MLton port for OpenBSD 5.9 can be found here: https://github.com/extensibl/ports

The mlton-bootstrap README in the above repository contains notes on how to bootstrap the older version of MLton. However, the port is not completed exactly because there were difficulties bootstrapping MLton in offline mode with just MLton sources available.

[hosewiejacke]

Thanks! I'm not sure I have the skills to finish the port, though.
Do you know if it's possible to cross compile it on Linux?

[AlexanderAA]

I would suggest to try and get it done the right way from the start, both OpenBSD and MLton are many commits ahead, so it might just work.

There are some instructions in the MLton documentation and wiki.

Cross-compilation notes for the older version of MLton are here, as well as the resulting files, needed to bootstrap the compiler on OpenBSD: https://github.com/extensibl/ports/blob/master/mlton-bootstrap/bootstrap/

[MatthewFluet]

It should be possible to either actually cross-compile on Linux (i.e., produce OpenBSD binaries on a Linux machine) or to indirectly cross-compile on Linux (i.e., use the Linux machine to produce the bootstrap files that will then be compiled on the OpenBSD machine).

See http://mlton.org/PortingMLton for some details, especially the Bootstrap section.

[hosewiejacke]

Thanks for comming back to this issue. ### cross compiling In order to use `-target` I need a GCC version that can cross compile[0]. I think that's where I gave up. ### bootstrapping That's what I tried along the lines: - install mlton on OSX - vim /usr/local/bin/mlton * add `-keep g` to `doit "$lib"` - download mlton source - cd into mlton source code - vim bin/mlton-script * add `-keep g` to `doit "$lib"` - make CC=clang - scp source to OpenBSD - vim runtime/util/die.c * include stdlib.h, stdio.h, errno.h, stdarg.h, string.h - cd runtime/util * clang -c die.c - `clang -std=gnu11 -fno-common -pedantic -Wall -Wextra -Wformat=2 \ -Wswitch-default -Wswitch-enum -Wuninitialized -Winit-self \ -Wstrict-aliasing=2 -Wfloat-equal -Wundef -Wshadow -Wpointer-arith \ -Wbad-function-cast -Wcast-qual -Wwrite-strings -Waggregate-return \ -Wstrict-prototypes -Wold-style-definition -Wmissing-prototypes \ -Wmissing-declarations -Wmissing-field-initializers -Wmissing-noreturn \ -Wmissing-format-attribute -Wredundant-decls -Wnested-externs \ -fvisibility=hidden -m64 -I. -Iplatform -Wdisabled-optimization -O2 \ -fomit-frame-pointer -c -o build/lib/mlton/mlton-compile \ -Lbuild/lib/mlton/targets/self -L/usr/local/lib \ mlton/mlton-compile.135.c -lmlton -lgmp -lgdtoa -lm \ -Ibuild/lib/mlton/include -I build/lib/mlton/targets/self/include` That failed, too. I don't remember the error message, though. [0] http://www.mlton.org/CrossCompiling

[MatthewFluet]

One problem with keeping the generated .c files on MacOS with -target self is that you may have embedded libc constants from MacOSX that don't make sense on OpenBSD. You really need to build the runtime system and the constants file on the OpenBSD system.

[hosewiejacke]

One problem with keeping the generated .c files on MacOS with `-target self` is that you may have embedded libc constants from MacOSX that don't make sense on OpenBSD.

Thanks, I didn't think about that.

You really need to build the runtime system and the constants file on the OpenBSD system.

Can you elaborate a little bit on this? From reading [0] a had the impression `mlton -keep g && scp` is the way to go:

Building and maintaining cross-compiling gcc's is complex. You may find it simpler to use mlton -keep g to generate the files on the host, then copy the files to the target, and then use gcc or mlton on the target to compile the files.

[0] http://mlton.org/CrossCompiling

[MatthewFluet]

The essential steps (albeit, cribbed together from different pages) is

1. Use bin/add-cross to build the runtime and constants on a target machine and pull those files back to the host machine. Although the script is named add-cross, you don't actually need gcc cross-compiling tools to do this.
2. Use bin/save-bootstrap-source to build the bootstrap .c files on the host machine, but using -target amd64-openbsd; this will use the constants gathered on the target machine.
3. Now copy the bootstrap .c files over to the target machine to compile and link with gcc.

Essentially, this is the Bootstrap section of http://mlton.org/PortingMLton, but with the additional initial step of running bin/add-cross (which was mentioned in the previous Running the regressions with a cross compiler section of that page)

[hosewiejacke]

Thanks for your patience with a noob! Unfourtunately, I didn't try these steps yet. (Time, you know...) Feel free to close the issue for now. I hope to add a comment if I check out your suggestions.

[hosewiejacke]

bin/add-cross fails in line 160 with

.../mlton/build/bin/mlton: No such file or directory

If I replace the path with /usr/bin/mlton it says

invalid target: amd64-pc-openbsd

Is it correct that there should be a binary in .../mlton/build/bin?

PS: The tar archive, that gets copied to the target, doesn't include the Makefile.config. I copied it by hand to make ./bin/mmake happy.

[MatthewFluet]

I think that bin/add-cross assumes that you have already done make all on the local machine; that will create the binary in mlton/build/bin.

Yes, Makefile.config should be included in the archive sent to the remote machine.

[hosewiejacke]

After `make all` the binary is there. But even though `make` says Build of MLton succeeded. the `./bin/add-cross amd64-pc-openbsd amd64 openbsd <target>` complains with invalid target: amd64-pc-openbsd . PS: If I nag to much, just tell me.

[MatthewFluet]

Can you tell where in add-cross that complaint is coming from?

[hosewiejacke]

Line 160: "$src/build/bin/mlton" -target $crossTarget ...

[MatthewFluet]

Then something went wrong earlier in the script with either building the runtime on the target system or copying files from the target system back to the host system. On the host, you should have a ./build/lib/mlton/targets/amd64-pc-openbsd directory that is populated with at least arch, os, sizes, and some lib*.a files.

[MatthewFluet]

Maybe no longer of interest, but #380 has streamlined bootstrapping MLton on new platforms. With it, I was able to bootstrap on amd64-openbsd; the resulting amd64-openbsd binary release file is at: https://downloads.sourceforge.net/project/mlton/mlton/experimental/20200523/mlton-20200523.150430-gb1b624ad3-1.amd64-openbsd.tgz

[barracuda156]

@MatthewFluet I consider using OpenBSD as a second system on my PowerPC hardware, if that works, I will be interested to build mlton there too. (Not sure if OpenBSD has it presently though.)