[GC] Fix order of operations in TypeRefiningGUFA: Restrictions must propagate (#7462)

We must first find global restrictions, then propagate, so that the
restrictions propagate.

Author: kripken

src/passes/TypeRefining.cpp

@@ -190,9 +190,6 @@ struct TypeRefining : public Pass {
       }
     }
 
-    // Propagate to supertypes, so no field is less refined than its super.
-    propagator.propagateToSuperTypes(finalInfos);
-
     // Take into account possible problems. This pass only refines struct
     // fields, and when we refine in a way that exceeds the wasm type system
     // then we fix that up with a cast (see below). However, we cannot use casts
@@ -225,6 +222,9 @@ struct TypeRefining : public Pass {
         }
       }
     }
+
+    // Propagate to supertypes, so no field is less refined than its super.
+    propagator.propagateToSuperTypes(finalInfos);
   }
 
   void useFinalInfos(Module* module, Propagator& propagator) {

test/lit/passes/type-refining-gufa.wast

@@ -383,3 +383,45 @@
   ;; GUFA:      (global $C (ref $struct) (struct.new_default $struct))
   (global $C (ref $struct) (struct.new_default $struct))
 )
+
+;; As above, but $struct has a supertype. We must propagate restrictions on it
+;; to its supertype. After doing so, we can refine the field to (ref func) in
+;; both, but no further, because of the restriction of global.get $A, which has
+;; that type.
+(module
+  (rec
+    ;; NRML:      (rec
+    ;; NRML-NEXT:  (type $super (sub (struct (field (ref func)))))
+    ;; GUFA:      (rec
+    ;; GUFA-NEXT:  (type $super (sub (struct (field (ref func)))))
+    (type $super (sub (struct (field funcref))))
+    ;; NRML:       (type $struct (sub $super (struct (field (ref func)))))
+    ;; GUFA:       (type $struct (sub $super (struct (field (ref func)))))
+    (type $struct (sub $super (struct (field funcref))))
+  )
+
+  ;; NRML:       (type $func (func))
+  ;; GUFA:       (type $func (func))
+  (type $func (func))
+
+  ;; NRML:      (global $A (ref func) (ref.func $func))
+  ;; GUFA:      (global $A (ref func) (ref.func $func))
+  (global $A (ref func) (ref.func $func))
+
+  ;; NRML:      (global $B (ref $struct) (struct.new $struct
+  ;; NRML-NEXT:  (global.get $A)
+  ;; NRML-NEXT: ))
+  ;; GUFA:      (global $B (ref $struct) (struct.new $struct
+  ;; GUFA-NEXT:  (global.get $A)
+  ;; GUFA-NEXT: ))
+  (global $B (ref $struct) (struct.new $struct
+    (global.get $A)
+  ))
+
+  ;; NRML:      (func $func (type $func)
+  ;; NRML-NEXT: )
+  ;; GUFA:      (func $func (type $func)
+  ;; GUFA-NEXT: )
+  (func $func (type $func)
+  )
+)