Support new locations of unix, str and dynlink

Signed-off-by: David Allsopp <david.allsopp@metastack.com>

CHANGES.md

@@ -1,3 +1,8 @@
+2.9.4 (unreleased)
+------------------
+
+- Support new locations of unix, str, dynlink in OCaml >= 5.0 (#5582, @dra27)
+
 2.9.3 (26/01/2022)
 ------------------
 

boot/duneboot.ml

@@ -572,6 +572,8 @@ module Config : sig
   val ocaml_config : unit -> string StringMap.t Fiber.t
 
   val output_complete_obj_arg : string
+
+  val unix_library_flags : string list
 end = struct
   let ocaml_version = Scanf.sscanf Sys.ocaml_version "%d.%d" (fun a b -> (a, b))
 
@@ -650,6 +652,12 @@ end = struct
       "-custom"
     else
       "-output-complete-exe"
+
+  let unix_library_flags =
+    if ocaml_version >= (5, 0) then
+      [ "-I"; "+unix" ]
+    else
+      []
 end
 
 let insert_header fn ~header =
@@ -1031,7 +1039,7 @@ let resolve_externals external_libraries =
     let convert = function
       | "threads.posix" ->
         ("threads" ^ Config.ocaml_archive_ext, [ "-I"; "+threads" ])
-      | "unix" -> ("unix" ^ Config.ocaml_archive_ext, [])
+      | "unix" -> ("unix" ^ Config.ocaml_archive_ext, Config.unix_library_flags)
       | s -> fatal "unhandled external library %s" s
     in
     let externals = List.map ~f:convert external_libraries in

bootstrap.ml

@@ -91,14 +91,18 @@ let () =
       (compiler, Some "--secondary")
   in
   exit_if_non_zero
-    (runf "%s %s -w -24 -g -o %s -I boot unix.cma %s" compiler
+    (runf "%s %s -w -24 -g -o %s -I boot %sunix.cma %s" compiler
        (* Make sure to produce a self-contained binary as dlls tend to cause
           issues *)
        (if v < (4, 10, 1) then
          "-custom"
        else
          "-output-complete-exe")
        prog
+       (if v >= (5, 0, 0) then
+         "-I +unix "
+       else
+         "")
        (List.map modules ~f:(fun m -> m ^ ".ml") |> String.concat ~sep:" "));
   let args = Array.to_list (Array.sub Sys.argv 1 (Array.length Sys.argv - 1)) in
   let args =

src/dune_rules/findlib/meta.ml

@@ -198,6 +198,12 @@ let builtins ~stdlib_dir ~version:ocaml_version =
     ; entries = [ version; main_modules [ name ] ]
     }
   in
+  let sandbox_if_necessary dir =
+    if Ocaml_version.has_sandboxed_otherlibs ocaml_version then
+      "+" ^ dir
+    else
+      "+"
+  in
   let compiler_libs =
     let sub name ?kind ?exists_if_ext deps =
       Package
@@ -220,8 +226,8 @@ let builtins ~stdlib_dir ~version:ocaml_version =
     }
   in
   let stdlib = dummy "stdlib" in
-  let str = simple "str" [] ~dir:"+" in
-  let unix = simple ~labels:true "unix" [] ~dir:"+" in
+  let str = simple "str" [] ~dir:(sandbox_if_necessary "str") in
+  let unix = simple ~labels:true "unix" [] ~dir:(sandbox_if_necessary "unix") in
   let bigarray =
     if
       Ocaml_version.stdlib_includes_bigarray ocaml_version
@@ -231,7 +237,7 @@ let builtins ~stdlib_dir ~version:ocaml_version =
     else
       simple "bigarray" [ "unix" ] ~dir:"+"
   in
-  let dynlink = simple "dynlink" [] ~dir:"+" in
+  let dynlink = simple "dynlink" [] ~dir:(sandbox_if_necessary "dynlink") in
   let bytes = dummy "bytes" in
   let result = dummy "result" in
   let uchar = dummy "uchar" in

src/dune_rules/ocaml_version.ml

@@ -49,3 +49,7 @@ let custom_or_output_complete_exe version =
 let ocamlopt_always_calls_library_linker version = version < (4, 12, 0)
 
 let has_sys_opaque_identity version = version >= (4, 3, 0)
+
+let has_bigarray_library version = version < (5, 0, 0)
+
+let has_sandboxed_otherlibs version = version >= (5, 0, 0)

src/dune_rules/ocaml_version.mli

@@ -68,3 +68,10 @@ val ocamlopt_always_calls_library_linker : t -> bool
 
 (** Whether [Sys.opaque_identity] is in the standard library *)
 val has_sys_opaque_identity : t -> bool
+
+(** Whether [bigarray] {e library} exists *)
+val has_bigarray_library : t -> bool
+
+(** Whether [dynlink], [str] and [unix] are in subdirectories of the standard
+    library *)
+val has_sandboxed_otherlibs : t -> bool

src/ocaml-config/ocaml_config.ml

@@ -513,7 +513,14 @@ let make vars =
     let cmt_magic_number = get vars "cmt_magic_number" in
     let windows_unicode = get_bool vars "windows_unicode" in
     let natdynlink_supported =
-      Sys.file_exists (Filename.concat standard_library "dynlink.cmxa")
+      let lib = "dynlink.cmxa" in
+      let lib =
+        if version >= (5, 0, 0) then
+          Filename.concat "dynlink" lib
+        else
+          lib
+      in
+      Sys.file_exists (Filename.concat standard_library lib)
     in
     let file =
       let stdlib = Path.external_ (Path.External.of_string standard_library) in