Runtime: allow dynlink of precompiled js with separate compilation

compiler/tests-dynlink-js/dune

@@ -2,7 +2,9 @@
  (name main)
  (modules main)
  (libraries js_of_ocaml)
- (modes byte))
+ (link_flags
+  (:standard -linkall))
+ (modes js byte))
 
 (rule
  (target main.js)
@@ -19,15 +21,44 @@
  (action
   (run %{bin:js_of_ocaml} %{dep:./plugin.cmo})))
 
+(rule
+ (target plugin2.cma)
+ (action
+  (run
+   %{bin:ocamlc}
+   -a
+   %{dep:./plugin2a.ml}
+   %{dep:./plugin2b.ml}
+   -o
+   plugin2.cma)))
+
+(rule
+ (target plugin2.js)
+ (action
+  (run %{bin:js_of_ocaml} %{dep:./plugin2.cma})))
+
 (rule
  (target main.out)
- (deps plugin.js)
+ (deps plugin.js plugin2.js)
  (action
   (with-outputs-to
    %{target}
    (run %{bin:node} %{dep:./main.js}))))
 
+(rule
+ (target main.out2)
+ (deps plugin.js plugin2.js)
+ (action
+  (with-outputs-to
+   %{target}
+   (run %{bin:node} %{dep:./main.bc.js}))))
+
 (rule
  (alias runtest)
  (action
   (diff main.out.expected main.out)))
+
+(rule
+ (alias runtest)
+ (action
+  (diff main.out.expected main.out2)))

compiler/tests-dynlink-js/main.ml

@@ -5,3 +5,5 @@ let require s =
   Js.Unsafe.fun_call (Js.Unsafe.js_expr "require") [| Js.Unsafe.inject (Js.string s) |]
 
 let () = require "./plugin.js"
+
+let () = require "./plugin2.js"

runtime/stdlib.js

@@ -150,11 +150,15 @@ var caml_global_data = [0];
 //Requires: caml_jsstring_of_string
 function caml_build_symbols(symb) {
   var r = {};
+  var max = -1;
   if (symb) {
     for (var i = 1; i < symb.length; i++) {
-      r[caml_jsstring_of_string(symb[i][1])] = symb[i][2];
+      var idx = symb[i][2];
+      max = Math.max(max, idx);
+      r[caml_jsstring_of_string(symb[i][1])] = idx;
     }
   }
+  r.next_idx = max + 1;
   return r;
 }
 
@@ -173,7 +177,10 @@ function caml_register_global(n, v, name_opt) {
       var nid = caml_global_data.symidx[name];
       if (nid >= 0) n = nid;
       else {
-        caml_failwith("caml_register_global: cannot locate " + name);
+        // The unit is unknown, this can happen when dynlinking a precompiled js,
+        // let's allocate a fresh idx.
+        var n = caml_global_data.symidx.next_idx++;
+        caml_global_data.symidx[name] = n;
       }
     }
   }