Fix checking of ref.func index declarations (#1894)

The validation was overly strict for ref.func index uses. In the spec,
the ref index just needs to appear in

  "the set of function indices occurring in the module, except in its
   functions or start function."

which includes uses in the global and export sections.

Fixes issue #1893

1 files changed, 8 insertions, 1 deletions

diff --git a/src/shared-validator.cc b/src/shared-validator.cc
index 5d9de4fe..086ca68e 100644
--- a/src/shared-validator.cc
+++ b/src/shared-validator.cc
@@ -211,6 +211,7 @@ Result SharedValidator::OnExport(const Location& loc,
   switch (kind) {
     case ExternalKind::Func:
       result |= CheckFuncIndex(item_var);
+      declared_funcs_.insert(item_var.index());
       break;
 
     case ExternalKind::Table:
@@ -951,7 +952,13 @@ Result SharedValidator::OnRefFunc(const Location& loc, Var func_var) {
   Result result = CheckInstr(Opcode::RefFunc, loc);
   result |= CheckFuncIndex(func_var);
   if (Succeeded(result)) {
-    check_declared_funcs_.push_back(func_var);
+    // References in initializer expressions are considered declarations, as
+    // opposed to references in function bodies that are considered usages.
+    if (in_init_expr_) {
+      declared_funcs_.insert(func_var.index());
+    } else {
+      check_declared_funcs_.push_back(func_var);
+    }
     Index func_type = GetFunctionTypeIndex(func_var.index());
     result |= typechecker_.OnRefFuncExpr(func_type);
   }