Re: [Caml-list] Can't build a target with C stubs using ocamlbuild

[Gabriel Scherer <gabriel.scherer@gmail.com>]

(Replying in-list as other people may be interested)

On Fri, Jun 5, 2015 at 7:09 PM, Christiano F. Haesbaert
<haesbaert@haesbaert.org> wrote:
> What is the common workflow to test such diff ?
>
> Is there a way to pin the compiler in opam ?

My personal workflow is to use my script
  https://github.com/gasche/opam-compiler-conf
which creates an opam switch from a compiler directory, using the
compiler version and git branch name to choose the switch name.

Steps are:
- install the opam-compiler-conf script in your $PATH *outside* opam
(otherwise you will need to install it in all switches, pain)
- clone the compiler somewhere (and go to the branch you want to test)
- apply the patch you want to test
- opam compiler-conf configure (instead of "./configure" as suggested by README)
- make world.opt
- opam compiler-conf install (instead of "make install" as suggested by README)

This will create a switch with the compiler you installed named, for
example, 4.02.2+local-git-4.02 (more generally
$OCAMLVER+local-git-$BRANCHNAME). You can install opam packages and
test them as in any switch.

Then, if you modify the compiler again and make world.opt again, you can use
- make install
  from the compiler directory to install the compiler without
reinstalling the OPAM packages (if the binary interface didn't change
and recompilation is not needed)
or
- opam compiler-conf reinstall
  to also recompile all the OPAM packages of the script

(Another common way to get a switch: pull-request made against
github/ocaml/ocaml automatically create a corresponding switch.)

On Fri, Jun 5, 2015 at 7:09 PM, Christiano F. Haesbaert
<haesbaert@haesbaert.org> wrote:
> Thanks, off list,
>
> What is the common workflow to test such diff ?
>
> Is there a way to pin the compiler in opam ?
>
> On 5 June 2015 at 18:47, Gabriel Scherer <gabriel.scherer@gmail.com> wrote:
>> I reported and proposed a fix at
>>   http://caml.inria.fr/mantis/view.php?id=6893
>>
>> On Fri, Jun 5, 2015 at 4:24 PM, Gabriel Scherer
>> <gabriel.scherer@gmail.com> wrote:
>>> This seems to be an ocamlbuild bug that should be reported on the bugtracker:
>>>   http://caml.inria.fr/mantis/
>>>
>>> On Fri, Jun 5, 2015 at 3:55 PM, Christiano F. Haesbaert
>>> <haesbaert@haesbaert.org> wrote:
>>>> Just one more question, now with the real code, I was able to move
>>>> everything to myocamlbuild, but I'm getting a warning:
>>>> File "_tags", line 10, characters 12-28:
>>>> Warning: the tag "linkdep(stubs.o)" is not used in any flag
>>>> declaration, so it will have no effect; it may be a typo. Otherwise
>>>> use `mark_tag_used` in your myocamlbuild.ml to disable this warning.
>>>>
>>>> ## build.sh ##
>>>> ocamlbuild -use-ocamlfind all.otarget $@
>>>>
>>>> ## _tags line ##
>>>> <*.native>: linkdep(stubs.o)
>>>>
>>>> ## myocamlbuild.ml ##
>>>> open Ocamlbuild_plugin;;
>>>> dispatch begin function
>>>>   | After_rules ->
>>>>     pflag ["ocaml";"compile";] "ppopt" (fun s -> S [A"-ppopt"; A s]);
>>>>     pflag ["ocaml";"ocamldep";] "ppopt" (fun s -> S [A"-ppopt"; A s]);
>>>>     pdep ["link"] "linkdep" (fun param -> [param])
>>>>   | _ -> ()
>>>> end;;
>>>>
>>>> It seems to be the same case as
>>>> http://stackoverflow.com/questions/25585813/mark-tag-used-warning-with-ocaml-4-02-0
>>>>
>>>> Should I just use mark_tag_used ? It seems something else is wrong
>>>> since the tag is actually used.
>>>>
>>>>
>>>> On 5 June 2015 at 12:47, Christiano F. Haesbaert
>>>> <haesbaert@haesbaert.org> wrote:
>>>>> On 5 June 2015 at 12:38, Jeremy Yallop <yallop@gmail.com> wrote:
>>>>>> On 5 June 2015 at 11:29, Christiano F. Haesbaert
>>>>>> <haesbaert@haesbaert.org> wrote:
>>>>>>> ### toto_c.c ###
>>>>>>> ### toto_c.ml ###
>>>>>>
>>>>>> Both of these files will be compiled to object files called
>>>>>> 'toto_c.o'.  Renaming one of them (e.g. toto_c.c to toto_c_stubs.c)
>>>>>> should fix the problem.
>>>>>
>>>>> Hooray, great, that did the trick, thanks a lot :D.
>>>>
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