Add a way to grab a code ref from an SC; will be needed for the new f…

…ixup handling code.

src/HLL/World.pm

@@ -102,6 +102,11 @@ class HLL::World {
         $past
     }
 
+    # Gets a code ref from the SC.
+    method get_slot_past_for_code_ref_at($idx) {
+        PAST::Op.new( :pirop('nqp_get_sc_code_ref Psi'), $!handle, $idx );
+    }
+
     # Utility sub to wrap PAST with slot setting.
     method set_slot_past($slot, $past_to_set) {
         return PAST::Op.new( :pirop('nqp_set_sc_object vsiP'),
@@ -147,9 +152,11 @@ class HLL::World {
 
     # Adds a code reference to the root set of code refs.
     method add_root_code_ref($code_ref, $past_block) {
-        pir::nqp_add_code_ref_to_sc__vPiP($!sc, $!num_code_refs, $code_ref);
+        my $code_ref_idx := $!num_code_refs;
         $!num_code_refs := $!num_code_refs + 1;
         $!code_ref_blocks.push($past_block);
+        pir::nqp_add_code_ref_to_sc__vPiP($!sc, $!num_code_refs, $code_ref);
+        $code_ref_idx
     }
 
     # Checks if we are in pre-compilation mode.

src/ops/nqp.ops

@@ -1447,6 +1447,27 @@ inline op nqp_get_sc_object(out PMC, in STR, in INT) :base_core {
             $2);
 }
 
+
+/*
+
+=item nqp_get_sc_code_ref()
+
+Fetches the code ref from the serialization context keyed by handle and index.
+
+=cut
+
+*/
+inline op nqp_get_sc_code_ref(out PMC, in STR, in INT) :base_core {
+    PMC *sc = SC_get_sc(interp, $2);
+    if (!PMC_IS_NULL(sc))
+        $1 = SC_get_code(interp, sc, $3);
+    else
+        Parrot_ex_throw_from_c_args(interp, NULL, EXCEPTION_INVALID_OPERATION,
+            "Cannot fetch code ref from non-existent serialization context %Ss",
+            $2);
+}
+
+
 /*
 
 =item nqp_get_sc()