Compiler: fix link of packed modules

compiler/lib/ocaml_compiler.ml

@@ -228,6 +228,21 @@ module Cmo_format = struct
   let requires (t : t) = List.map t.cu_required_compunits ~f:(fun (Compunit u) -> u)
   [@@if ocaml_version >= (5, 2, 0)]
 
+  let provides (t : t) =
+    List.filter_map t.cu_reloc ~f:(fun ((reloc : Cmo_format.reloc_info), _) ->
+        match reloc with
+        | Reloc_setglobal i -> Some (Ident.name i)
+        | Reloc_getglobal _ | Reloc_literal _ | Reloc_primitive _ -> None)
+  [@@if ocaml_version < (5, 2, 0)]
+
+  let provides (t : t) =
+    List.filter_map t.cu_reloc ~f:(fun ((reloc : Cmo_format.reloc_info), _) ->
+        match reloc with
+        | Reloc_setcompunit (Compunit u) -> Some u
+        | Reloc_getcompunit _ | Reloc_getpredef _ | Reloc_literal _ | Reloc_primitive _ ->
+            None)
+  [@@if ocaml_version >= (5, 2, 0)]
+
   let primitives (t : t) = t.cu_primitives
 
   let imports (t : t) = t.cu_imports

compiler/lib/ocaml_compiler.mli

@@ -66,6 +66,8 @@ module Cmo_format : sig
 
   val requires : t -> string list
 
+  val provides : t -> string list
+
   val primitives : t -> string list
 
   val force_link : t -> bool

compiler/lib/unit_info.ml

@@ -48,7 +48,8 @@ let of_primitives l =
 
 let of_cmo (cmo : Cmo_format.compilation_unit) =
   let open Ocaml_compiler in
-  let provides = StringSet.singleton (Cmo_format.name cmo) in
+  (* A packed librariy register global for packed modules. *)
+  let provides = StringSet.of_list (Cmo_format.name cmo :: Cmo_format.provides cmo) in
   let requires = StringSet.of_list (Cmo_format.requires cmo) in
   let requires = StringSet.diff requires provides in
   let effects_without_cps =