flambda-backend: Enable Domain module fully on runtime5 (#2464)

Author: mshinwell

asmcomp/amd64/emit.mlp

@@ -932,7 +932,7 @@ let emit_instr env fallthrough i =
     I.movzx (res8 i 0) (res i 0)
   | Lop (Idls_get) ->
     if Config.runtime5
-    then  I.mov (domain_field Domainstate.Domain_dls_root) (res i 0)
+    then I.mov (domain_field Domainstate.Domain_dls_root) (res i 0)
     else Misc.fatal_error "Idls_get not implemented in runtime4."
   | Lreloadretaddr ->
       ()

middle_end/semantics_of_primitives.ml

@@ -160,7 +160,7 @@ let for_primitive (prim : Clambda_primitives.primitive) =
   | Pget_header _ -> No_effects, No_coeffects
   | Pdls_get ->
       (* only read *)
-      No_effects, No_coeffects
+      No_effects, Has_coeffects
 
 type return_type =
   | Float

runtime4/domain.c

@@ -175,3 +175,40 @@ CAMLprim value caml_ml_condition_broadcast(value wrapper)
 
   return (*caml_hook_condition_broadcast)(wrapper);
 }
+
+/* Dummy implementations to enable [Stdlib.Domain] to link. */
+
+CAMLprim value caml_recommended_domain_count(void)
+{
+  caml_failwith("Domains not supported on runtime4");
+}
+
+CAMLprim value caml_ml_domain_cpu_relax(void)
+{
+  caml_failwith("Domains not supported on runtime4");
+}
+
+CAMLprim value caml_init_domain_self(void)
+{
+  caml_failwith("Domains not supported on runtime4");
+}
+
+CAMLprim value caml_domain_spawn(void)
+{
+  caml_failwith("Domains not supported on runtime4");
+}
+
+CAMLprim value caml_ml_domain_id(void)
+{
+  caml_failwith("Domains not supported on runtime4");
+}
+
+CAMLprim value caml_domain_dls_set(void)
+{
+  caml_failwith("Domains not supported on runtime4");
+}
+
+CAMLprim value caml_domain_dls_get(void)
+{
+  caml_failwith("Domains not supported on runtime4");
+}