Support scoped anyref variable declarations (#958)

Author: jayphelps

NOTICE

@@ -17,6 +17,7 @@ under the licensing terms detailed in LICENSE:
 * Bowen Wang <[email protected]>
 * Emil Laine <[email protected]>
 * Stephen Paul Weber <[email protected]>
+* Jay Phelps <[email protected]>
 
 Portions of this software are derived from third-party works licensed under
 the following terms:

src/flow.ts

@@ -324,6 +324,7 @@ export class Flow {
       case NativeType.F32: { temps = parentFunction.tempF32s; break; }
       case NativeType.F64: { temps = parentFunction.tempF64s; break; }
       case NativeType.V128: { temps = parentFunction.tempV128s; break; }
+      case NativeType.Anyref: { temps = parentFunction.tempAnyrefs; break; }
       default: throw new Error("concrete type expected");
     }
     var local: Local;
@@ -395,6 +396,10 @@ export class Flow {
         temps = parentFunction.tempV128s || (parentFunction.tempV128s = []);
         break;
       }
+      case NativeType.Anyref: {
+        temps = parentFunction.tempAnyrefs || (parentFunction.tempAnyrefs = []);
+        break;
+      }
       default: throw new Error("concrete type expected");
     }
     assert(local.index >= 0);

src/module.ts

@@ -1423,6 +1423,10 @@ export class Module {
             // TODO
             return 0;
           }
+          // Not possible to clone an anyref as it is opaque
+          case NativeType.Anyref: {
+            return 0;
+          }
           default: {
             throw new Error("concrete type expected");
           }

src/program.ts

@@ -2900,6 +2900,7 @@ export class Function extends TypedElement {
   tempF32s: Local[] | null = null;
   tempF64s: Local[] | null = null;
   tempV128s: Local[] | null = null;
+  tempAnyrefs: Local[] | null = null;
 
   // used by flows to keep track of break labels
   nextBreakId: i32 = 0;

tests/compiler/features/reference-types.ts

@@ -3,7 +3,10 @@
 export declare function external(a: anyref): anyref;
 
 export function internal(a: anyref): anyref {
-  return a;
+  const b = external(a);
+  let c = external(b);
+  var d = external(c);
+  return d;
 }
 
 // can use reflection to work with anyref values

tests/compiler/features/reference-types.untouched.wat

@@ -30,7 +30,7 @@
   if
    i32.const 0
    i32.const 24
-   i32.const 16
+   i32.const 19
    i32.const 0
    call $~lib/builtins/abort
    unreachable
@@ -45,7 +45,19 @@
   call $~lib/bindings/console/log
  )
  (func $features/reference-types/internal (; 6 ;) (type $FUNCSIG$aa) (param $0 anyref) (result anyref)
+  (local $1 anyref)
+  (local $2 anyref)
+  (local $3 anyref)
   local.get $0
+  call $features/reference-types/external
+  local.set $1
+  local.get $1
+  call $features/reference-types/external
+  local.set $2
+  local.get $2
+  call $features/reference-types/external
+  local.set $3
+  local.get $3
  )
  (func $start (; 7 ;) (type $FUNCSIG$v)
   call $start:features/reference-types