Enable ref.func global initializers (#1380)

* Fix comment referencing an outdated instruction name

* cranelift-wasm: Enable `ref.func` global initializers

cranelift/wasm/src/sections_translator.rs

@@ -224,6 +224,9 @@ pub fn parse_global_section(
                 GlobalInit::V128Const(V128Imm::from(value.bytes().to_vec().as_slice()))
             }
             Operator::RefNull => GlobalInit::RefNullConst,
+            Operator::RefFunc { function_index } => {
+                GlobalInit::RefFunc(FuncIndex::from_u32(function_index))
+            }
             Operator::GlobalGet { global_index } => {
                 GlobalInit::GetGlobal(GlobalIndex::from_u32(global_index))
             }

cranelift/wasm/src/translation_utils.rs

@@ -81,10 +81,12 @@ pub enum GlobalInit {
     F64Const(u64),
     /// A `vconst`.
     V128Const(V128Imm),
-    /// A `get_global` of another global.
+    /// A `global.get` of another global.
     GetGlobal(GlobalIndex),
     /// A `ref.null`.
     RefNullConst,
+    /// A `ref.func <index>`.
+    RefFunc(FuncIndex),
     ///< The global is imported from, and thus initialized by, a different module.
     Import,
 }

cranelift/wasmtests/ref-func-0.wat

@@ -0,0 +1,12 @@
+(module
+  (func $imported (import "env" "f") (param i32) (result i32))
+  (func $local (result anyref anyref funcref funcref)
+    global.get 0
+    global.get 1
+    global.get 2
+    global.get 3)
+
+  (global (export "anyref-imported") anyref (ref.func $imported))
+  (global (export "anyref-local") anyref (ref.func $local))
+  (global (export "funcref-imported") funcref (ref.func $imported))
+  (global (export "funcref-local") funcref (ref.func $local)))