Update reference types (#3084)

Align with the current state of the reference types proposal:
* Remove `nullref`
* Remove `externref` and `funcref` subtyping
* A `Literal` of a nullable reference type can now represent `null` (previously was type `nullref`)
* Update the tests and temporarily comment out those tests relying on subtyping

Author: dcodeIO

scripts/gen-s-parser.py

@@ -50,7 +50,6 @@
     ("v128.pop",       "makePop(Type::v128)"),
     ("funcref.pop",    "makePop(Type::funcref)"),
     ("externref.pop",  "makePop(Type::externref)"),
-    ("nullref.pop",    "makePop(Type::nullref)"),
     ("exnref.pop",     "makePop(Type::exnref)"),
     ("i32.load",       "makeLoad(s, Type::i32, /*isAtomic=*/false)"),
     ("i64.load",       "makeLoad(s, Type::i64, /*isAtomic=*/false)"),

src/asmjs/asm_v_wasm.cpp

@@ -56,7 +56,6 @@ AsmType wasmToAsmType(Type type) {
       assert(false && "v128 not implemented yet");
     case Type::funcref:
     case Type::externref:
-    case Type::nullref:
     case Type::exnref:
       assert(false && "reference types are not supported by asm2wasm");
     case Type::none:
@@ -84,8 +83,6 @@ char getSig(Type type) {
       return 'F';
     case Type::externref:
       return 'X';
-    case Type::nullref:
-      return 'N';
     case Type::exnref:
       return 'E';
     case Type::none:

src/binaryen-c.cpp

@@ -69,12 +69,12 @@ BinaryenLiteral toBinaryenLiteral(Literal x) {
       memcpy(&ret.v128, x.getv128Ptr(), 16);
       break;
     case Type::funcref:
-      ret.func = x.getFunc().c_str();
-      break;
-    case Type::nullref:
+      ret.func = x.isNull() ? nullptr : x.getFunc().c_str();
       break;
     case Type::externref:
     case Type::exnref:
+      assert(x.isNull());
+      break;
     case Type::none:
     case Type::unreachable:
       WASM_UNREACHABLE("unexpected type");
@@ -95,11 +95,10 @@ Literal fromBinaryenLiteral(BinaryenLiteral x) {
     case Type::v128:
       return Literal(x.v128);
     case Type::funcref:
-      return Literal::makeFuncref(x.func);
-    case Type::nullref:
-      return Literal::makeNullref();
+      return Literal::makeFunc(x.func);
     case Type::externref:
     case Type::exnref:
+      return Literal::makeNull(Type(x.type));
     case Type::none:
     case Type::unreachable:
       WASM_UNREACHABLE("unexpected type");
@@ -133,7 +132,6 @@ BinaryenType BinaryenTypeFloat64(void) { return Type::f64; }
 BinaryenType BinaryenTypeVec128(void) { return Type::v128; }
 BinaryenType BinaryenTypeFuncref(void) { return Type::funcref; }
 BinaryenType BinaryenTypeExternref(void) { return Type::externref; }
-BinaryenType BinaryenTypeNullref(void) { return Type::nullref; }
 BinaryenType BinaryenTypeExnref(void) { return Type::exnref; }
 BinaryenType BinaryenTypeUnreachable(void) { return Type::unreachable; }
 BinaryenType BinaryenTypeAuto(void) { return uintptr_t(-1); }
@@ -1264,8 +1262,11 @@ BinaryenExpressionRef BinaryenPop(BinaryenModuleRef module, BinaryenType type) {
     Builder(*(Module*)module).makePop(Type(type)));
 }
 
-BinaryenExpressionRef BinaryenRefNull(BinaryenModuleRef module) {
-  return static_cast<Expression*>(Builder(*(Module*)module).makeRefNull());
+BinaryenExpressionRef BinaryenRefNull(BinaryenModuleRef module,
+                                      BinaryenType type) {
+  Type type_(type);
+  assert(type_.isNullable());
+  return static_cast<Expression*>(Builder(*(Module*)module).makeRefNull(type_));
 }
 
 BinaryenExpressionRef BinaryenRefIsNull(BinaryenModuleRef module,

src/binaryen-c.h

@@ -100,7 +100,6 @@ BINARYEN_API BinaryenType BinaryenTypeFloat64(void);
 BINARYEN_API BinaryenType BinaryenTypeVec128(void);
 BINARYEN_API BinaryenType BinaryenTypeFuncref(void);
 BINARYEN_API BinaryenType BinaryenTypeExternref(void);
-BINARYEN_API BinaryenType BinaryenTypeNullref(void);
 BINARYEN_API BinaryenType BinaryenTypeExnref(void);
 BINARYEN_API BinaryenType BinaryenTypeUnreachable(void);
 // Not a real type. Used as the last parameter to BinaryenBlock to let
@@ -826,7 +825,8 @@ BinaryenMemoryFill(BinaryenModuleRef module,
                    BinaryenExpressionRef dest,
                    BinaryenExpressionRef value,
                    BinaryenExpressionRef size);
-BINARYEN_API BinaryenExpressionRef BinaryenRefNull(BinaryenModuleRef module);
+BINARYEN_API BinaryenExpressionRef BinaryenRefNull(BinaryenModuleRef module,
+                                                   BinaryenType type);
 BINARYEN_API BinaryenExpressionRef
 BinaryenRefIsNull(BinaryenModuleRef module, BinaryenExpressionRef value);
 BINARYEN_API BinaryenExpressionRef BinaryenRefFunc(BinaryenModuleRef module,

src/gen-s-parser.inc

@@ -2560,17 +2560,9 @@ switch (op[0]) {
       default: goto parse_error;
     }
   }
-  case 'n': {
-    switch (op[1]) {
-      case 'o':
-        if (strcmp(op, "nop") == 0) { return makeNop(); }
-        goto parse_error;
-      case 'u':
-        if (strcmp(op, "nullref.pop") == 0) { return makePop(Type::nullref); }
-        goto parse_error;
-      default: goto parse_error;
-    }
-  }
+  case 'n':
+    if (strcmp(op, "nop") == 0) { return makeNop(); }
+    goto parse_error;
   case 'r': {
     switch (op[2]) {
       case 'f': {

src/ir/ExpressionManipulator.cpp

@@ -227,7 +227,9 @@ flexibleCopy(Expression* original, Module& wasm, CustomCopier custom) {
         builder.makeHost(curr->op, curr->nameOperand, std::move(operands));
       return ret;
     }
-    Expression* visitRefNull(RefNull* curr) { return builder.makeRefNull(); }
+    Expression* visitRefNull(RefNull* curr) {
+      return builder.makeRefNull(curr->type);
+    }
     Expression* visitRefIsNull(RefIsNull* curr) {
       return builder.makeRefIsNull(copy(curr->value));
     }

src/ir/abstract.h

@@ -103,7 +103,6 @@ inline UnaryOp getUnary(Type type, Op op) {
     }
     case Type::funcref:
     case Type::externref:
-    case Type::nullref:
     case Type::exnref:
     case Type::none:
     case Type::unreachable: {
@@ -268,7 +267,6 @@ inline BinaryOp getBinary(Type type, Op op) {
     }
     case Type::funcref:
     case Type::externref:
-    case Type::nullref:
     case Type::exnref:
     case Type::none:
     case Type::unreachable: {

src/ir/manipulation.h

@@ -40,9 +40,10 @@ template<typename InputType> inline Nop* nop(InputType* target) {
   return ret;
 }
 
-template<typename InputType> inline RefNull* refNull(InputType* target) {
+template<typename InputType>
+inline RefNull* refNull(InputType* target, Type type) {
   auto* ret = convert<InputType, RefNull>(target);
-  ret->finalize();
+  ret->finalize(type);
   return ret;
 }
 

src/ir/properties.h

@@ -93,10 +93,10 @@ inline bool isConstantExpression(const Expression* curr) {
 inline Literal getSingleLiteral(const Expression* curr) {
   if (auto* c = curr->dynCast<Const>()) {
     return c->value;
-  } else if (curr->is<RefNull>()) {
-    return Literal(Type::nullref);
-  } else if (auto* c = curr->dynCast<RefFunc>()) {
-    return Literal(c->func);
+  } else if (auto* n = curr->dynCast<RefNull>()) {
+    return Literal(n->type);
+  } else if (auto* r = curr->dynCast<RefFunc>()) {
+    return Literal(r->func);
   } else {
     WASM_UNREACHABLE("non-constant expression");
   }

src/js/binaryen.js-post.js

@@ -35,7 +35,6 @@ function initializeConstants() {
     ['v128', 'Vec128'],
     ['funcref', 'Funcref'],
     ['externref', 'Externref'],
-    ['nullref', 'Nullref'],
     ['exnref', 'Exnref'],
     ['unreachable', 'Unreachable'],
     ['auto', 'Auto']
@@ -2058,21 +2057,15 @@ function wrapModule(module, self = {}) {
     }
   };
 
-  self['nullref'] = {
-    'pop'() {
-      return Module['_BinaryenPop'](module, Module['nullref']);
-    }
-  };
-
   self['exnref'] = {
     'pop'() {
       return Module['_BinaryenPop'](module, Module['exnref']);
     }
   };
 
   self['ref'] = {
-    'null'() {
-      return Module['_BinaryenRefNull'](module);
+    'null'(type) {
+      return Module['_BinaryenRefNull'](module, type);
     },
     'is_null'(value) {
       return Module['_BinaryenRefIsNull'](module, value);