Directize: Refine results (WebAssembly#7974)

If the actual target is of a subtype, its results may be more refined.

Author: kripken

src/passes/Directize.cpp

@@ -189,9 +189,15 @@ struct FunctionDirectizer : public WalkerPass<PostWalker<FunctionDirectizer>> {
 
     // Everything looks good!
     auto name = std::get<CallUtils::Known>(info).target;
-    replaceCurrent(
-      Builder(*getModule())
-        .makeCall(name, operands, original->type, original->isReturn));
+    auto results = getModule()->getFunction(name)->getResults();
+    replaceCurrent(Builder(*getModule())
+                     .makeCall(name, operands, results, original->isReturn));
+
+    // When we call a function of a subtype of the call_indirect's call type, we
+    // may be refining results.
+    if (results != original->type) {
+      changedTypes = true;
+    }
   }
 };
 

test/lit/passes/directize-gc.wast

@@ -112,3 +112,40 @@
  )
 )
 
+;; call_indirect using the supertype. The direct call has a more refined type,
+;; which we must update the IR to.
+(module
+ (rec
+  ;; CHECK:      (rec
+  ;; CHECK-NEXT:  (type $super (sub (func (result (ref any)))))
+  (type $super (sub (func (result (ref any)))))
+  ;; CHECK:       (type $sub (sub $super (func (result (ref none)))))
+  (type $sub (sub $super (func (result (ref none)))))
+ )
+
+ ;; CHECK:      (table $table 42 funcref)
+ (table $table 42 funcref)
+ ;; CHECK:      (elem $elem (i32.const 0) $sub)
+ (elem $elem (i32.const 0) $sub)
+
+ ;; CHECK:      (func $super (type $super) (result (ref any))
+ ;; CHECK-NEXT:  (block $show-type (result (ref none))
+ ;; CHECK-NEXT:   (call $sub)
+ ;; CHECK-NEXT:  )
+ ;; CHECK-NEXT: )
+ (func $super (type $super) (result (ref any))
+  (block $show-type (result (ref any))
+   (call_indirect $table (type $super)
+    (i32.const 0)
+   )
+  )
+ )
+
+ ;; CHECK:      (func $sub (type $sub) (result (ref none))
+ ;; CHECK-NEXT:  (unreachable)
+ ;; CHECK-NEXT: )
+ (func $sub (type $sub) (result (ref none))
+  (unreachable)
+ )
+)
+