Get wasm_of_ocaml up-to-date with js_of_ocaml

[vouillon]

We have a branch jsoo-tip which contains the changes we make to the Js_of_ocaml code in compiler/lib, and a branch jsoo-merge which contains some changes to the compiler/lib/wasm code to adapt to API changes in Js_of_ocaml.

• Make sure that we have a simple process to merge these two branches. The following almost works, but needs some adjustments (we possibly need to modify the branch jsoo-merge to make it simpler):

  git merge jsoo-tip -X theirs -X find-renames=100%
  git reset README.md && git checkout README.md
  git reset lib/js_of_ocaml/json.ml && git checkout lib/js_of_ocaml/json.ml
  git reset compiler/tests-toplevel/dune && git checkout compiler/tests-toplevel/dune
  (cd compiler/tests-compiler && dune exec -- gen-rules/gen.exe > dune.inc && git add dune.inc)
  git add .github/workflows/build.yml .github/workflows/changelog.yml
  

• Get the commits in branch jsoo-tip merged into js_of_ocaml. One of the commit conflicts with the double translation PR; we need to understand what to do about it.
  • Effects: keep track of CPS calls and distinguish CPS calls and trampolined calls ocsigen/js_of_ocaml#1648
  • Make number representations compatible with Wasm ocsigen/js_of_ocaml#1649
  • Stop exposing numbers as floats in the Js_of_ocaml library ocsigen/js_of_ocaml#1650
  • Make the tests for uncaught exceptions more portable ocsigen/js_of_ocaml#1652
  • Dom_html.html_entities: move error handling to the ML side ocsigen/js_of_ocaml#1653
  • Small changes in the internal APIs for Wasm ocsigen/js_of_ocaml#1654
  • Target-specific code ocsigen/js_of_ocaml#1655
  • Update typing of typed arrays to support Wasm, and test Typed_array.Bytes ocsigen/js_of_ocaml#1656
  • Build_info/Unit_info: conversion to and from string maps ocsigen/js_of_ocaml#1657
  • Runtime: implement Json output for Wasm ocsigen/js_of_ocaml#1660
  • Generate: explicit initialization ocsigen/js_of_ocaml#1662
• Merge branch jsoo-merge into wasm_of_ocaml. See Merge recent updates from js_of_ocaml #57.
  • Integrate ocsigen/js_of_ocaml#1497 #64
  • Integrate "added 'ellipse' method to canvasRenderingContext2D" (ocsigen/js_of_ocaml#1555) #65
  • Merge various recent compiler/lib/ updates from js_of_ocaml #67
  • Rename cps_calls into trampolined_calls for clarity #68
  • Sourcemap API changes from js_of_ocaml #69
  • Integrate latest changes to number representation from js_of_ocaml #70
  • Integrate changes to Document.constant_equal #71
  • Integrate "Target-specific code" (ocsigen/js_of_ocaml#1655) #85
• Check the changes made in the js_of_ocaml runtime since the code bases have diverged and update the wasm runtime accordingly. (Note that Add Typed_array.Bytes module ocsigen/js_of_ocaml#1609 makes use of primitives which are not implemented in Wasm. Edit: done)
  • We may have to modify what was done in Document non-trivial function Code.constant_equal, and fix related bugs ocsigen/js_of_ocaml#1659 regarding String _ and NativeString _.
• Actually merge the js_of_ocaml main branch into wasm_of_ocaml.
  • PR: Get wasm_of_ocaml up-to-date with js_of_ocaml by merging js_of_ocaml master #86
• Merge wasm_of_ocaml main back into js_of_ocaml master.
  • PR: to be opened

[OlivierNicole]

Currently after applying the process above, there are only two tests failing with OCaml 5.2.0:

• compiler/tests-full/stdlib.cma.expected.js. This is not very surprising, as changes were made to it in both JSOO and WSOO. It seems to me that the simplest way to handle this would be to promote it after the actual merge;
• compiler/tests-jsoo/test_marshal.ml. This is once again the compression problems that started with OCaml 5.1. I don’t have a good view of what happens here and it seems to depend on the machine, but it does not seem WSOO-specific.

[vouillon]

Regarding compiler/tests-full/stdlib.cma.expected.js, we should keep the version from jsoo-tip. I think that the file is not up to date in jsoo-tip and that the commit "Distinguish float arrays' should be amended to fix that.

By the way, the commit "Source_map_io API changes" should also be amended with these changes:

diff --git a/compiler/lib/source_map_io.unsupported.ml b/compiler/lib/source_map
_io.unsupported.ml
index dbdb35816c..2d4ecf1cc6 100644
--- a/compiler/lib/source_map_io.unsupported.ml
+++ b/compiler/lib/source_map_io.unsupported.ml
@@ -23,6 +23,8 @@ let to_string _ = fail ()
 
 let of_string _ = fail ()
 
-let to_file _ _ = fail ()
+let of_file_no_mappings _ = fail ()
+
+let to_file ?mappings:_ _ ~file:_ = fail ()
 
 let enabled = false

[OlivierNicole]

Regarding compiler/tests-full/stdlib.cma.expected.js, we should keep the version from jsoo-tip. I think that the file is not up to date in jsoo-tip and that the commit "Distinguish float arrays' should be amended to fix that.

Done, it works!

By the way, the commit "Source_map_io API changes" should also be amended with these changes:

diff --git a/compiler/lib/source_map_io.unsupported.ml b/compiler/lib/source_map
_io.unsupported.ml
index dbdb35816c..2d4ecf1cc6 100644
--- a/compiler/lib/source_map_io.unsupported.ml
+++ b/compiler/lib/source_map_io.unsupported.ml
@@ -23,6 +23,8 @@ let to_string _ = fail ()
 
 let of_string _ = fail ()
 
-let to_file _ _ = fail ()
+let of_file_no_mappings _ = fail ()
+
+let to_file ?mappings:_ _ ~file:_ = fail ()
 
 let enabled = false

Done.

[vouillon]

The marshaling test pass for me when producing JavaScript.

It fails with dune runtest --profile wasm (after implementing two missing primitives). I think that's because Marshal.header_size has changed in OCaml 5.1.0, so we need to adjust somehow the global $caml_marshal_header_size in runtime/wasm/marshal.wat depending on the OCaml version.

[OlivierNicole]

The marshaling test pass for me when producing JavaScript.

Not for me. This is completely obscure to me.

[OlivierNicole]

Status report: I rebased jsoo-tip onto JSOO master. Since then, test compiler/tests-toplevel/test_toplevel.js has been failing with --profile dev after merging jsoo-tip into jsoo-merge. I haven’t yet found the reason but maybe related to ocsigen/js_of_ocaml#1634?

I have also pushed missing primitives to jsoo-merge, as well as cherry-picked ocsigen/js_of_ocaml#1639. Primitives for the new BLAKE2B digests are still missing, as well as caml_zstd_initialize.

[hhugo]

ocsigen/js_of_ocaml#1634 adds a new test that checks that toplevel built with separate compilation works correctly.
Is it possible that such setup has never worked with the wasm backend ?

[OlivierNicole]

Hm, what is strange is that it is test_toplevel.js (so, the whole-compilation one IIUC) that has an uncaught exception, and it is with JS and not Wasm.

[OlivierNicole]

The bulk of the changes needed on the Js_of_ocaml side has been submitted as PRs there, there shouldn’t be many more except to fix problems.

[vouillon]

Hm, what is strange is that it is test_toplevel.js (so, the whole-compilation one IIUC) that has an uncaught exception, and it is with JS and not Wasm.

There is this error:

Error: The external function "caml_float_of_int" is not available

So, it seems Generate.init is not called (it defines caml_float_of_int as an alias to %identity).

This issue is already in branch jsoo-tip, by the way.

[vouillon]

So, it seems Generate.init is not called (it defines caml_float_of_int as an alias to %identity).

We can add it in Driver.from_string or in lib-dynlink/js_of_ocaml_compiler_dynlink.ml. Not sure which is best...

Oh, and the merged file test_toplevel/dune seems to miss some changes. Maybe we need to cherry-pick 390e6a2 on branch jsoo-merge?

[hhugo]

We can add it in Driver.from_string or in lib-dynlink/js_of_ocaml_compiler_dynlink.ml. Not sure which is best...

Maybe in Js_of_ocaml_compiler_dynlink.ml is best