dkml-compiler

POSIX Bourne shell scripts to compile the DKML distribution of OCaml.

There is also a dkml-base-compiler.opam that always compiles the latest DKML supported compiler. However the dkml-compiler repository supports will support more than one version of OCaml; you can get other versions by adding the diskuv-opam-repository to your Opam switch.

The diskuv-opam-repository is also necessary if you want to use a DKML version of the OCaml 4.x compiler on a non-Windows machine. The central Opam repository only introduced the DKML distribution in OCaml 5.x generally and OCaml 4.12 for Windows specifically.

Packages that rely on dkml-compiler

• dkml-component-ocamlcompiler
• dkml-component-ocamlrun
• dkml-component-opam
• dkml-runtime-apps

Directory Structure

Build Directories

Path	Description
dl/*.tar.gz	Opam extra-source downloads
dl/ocaml	Unpatched OCaml source from dl/ocaml.tar.gz
dl/ocaml/flexdll	Unpatched flexdll source from dl/flexdll.tar.gz
dkmldir/.dkmlroot	Properties file with the version of DKML based on the Opam version
dkmldir/vendor/dkml-compiler/src	A copy of the toplevel src/
dkmldir/vendor/drc	Source from dl/dkml-runtime-common.tar.gz

Opam Directories

Path	Description
$(opam var prefix)/src-ocaml	OCaml source patched for the host ABI
$(opam var prefix)/bin	OCaml host ABI binaries. Ex. ocamlopt
$(opam var prefix)/lib/ocaml	OCaml host ABI libraries. Ex. unix.cmxa
$(opam var prefix)/share/dkml-base-compiler/mlcross/<ABI>/src-ocaml	OCaml source patched for the target ABI
$(opam var prefix)/share/dkml-base-compiler/mlcross/<ABI>/bin	OCaml target ABI binaries. Ex. ocamlopt
$(opam var prefix)/share/dkml-base-compiler/mlcross/<ABI>/lib/ocaml	OCaml target ABI libraries. Ex. unix.cmxa

All ABI names are compatible with dkml-c-probe. The target ABI folders will not be present if DKML does not support cross-compiling on the host ABI. Currently only macOS has a target ABI.

There is another Opam package conf-dkml-cross-toolchain that can take the "mlcross" Opam directory structure and add it to findlib so that ocamlfind -toolchain <ABI> and dune build -x <ABI> work.

Developing

First run with-dkml make local-install on DkML on Windows, or make local-install on other platforms, to install the compiler in a local opam switch using an in-place build.

As a useful side-effect, the in-place build recreates the build directories that dkml-base-compiler.opam assembles. Even if the make local-install fails to build a working OCaml compiler, you still have all the directories ready for local development.

More developer documentation is in DEVELOPING.md.

Patching

In what follows, VER is a placeholder for the OCaml major version (ex. 4) and for the OCaml major+minor version in underscore formatting (ex. 4_12). The major version patches are applied first, and then the major+minor version patches are applied.

The patches are all available in src/p/.

• The OCaml source patched for the host ABI uses ocaml-common-VER-*.patch in lexographical order and ocaml-host-VER-*.patch in lexographical order.
• The OCaml source patched for the target ABI uses ocaml-common-VER-*.patch in lexographical order and ocaml-target-VER-*.patch in lexographical order.

It is important to realize that patches are applied in a particular order, and to structure the patches so they are more or less independent of each other.

When you make a patch, you should consult the Opam directory structure table and do a git log in the OCaml source patched ... directories. You must also run ./dk user.reindex in a Unix shell or PowerShell.

Optimization

If we have a prebuilt ocamlc.opt for an architecture ... possibly and likely for an old version of OCaml, it is used to save some initial bootstrapping time during ocaml install dkml-base-compiler.

Note that the prebuilt ocamlc.opt is optional. If it doesn't exist, then some extra time is spent during opam install. This optionality allows for:

1. Let's dkml-base-compiler build in CI.
2. Then ocamlc.opt can be saved forever as a CI release artifact.
3. Then ocamlc.opt can be used for all new compiler builds by modifying the download links in dkml-base-compiler.opam.

Status