Merge pull request #522 from takikawa/default_value

[js-api][test] Refine DefaultValue for new reference types

Author: rossberg

document/core/appendix/embedding.rst

@@ -630,11 +630,12 @@ Globals
    \end{array}
 
 
-.. index:: reference, reference type
+.. index:: reference, reference type, value type, value
 .. _embed-ref-type:
+.. _embed-val-default:
 
-References
-~~~~~~~~~~
+Values
+~~~~~~
 
 :math:`\F{ref\_type}(\store, \reff) : \reftype`
 ...............................................
@@ -656,6 +657,20 @@ References
    In such cases, this function may return a less precise supertype.
 
 
+:math:`\F{val\_default}(\valtype) : \val`
+...............................................
+
+1. If :math:`\default_{valtype}` is not defined, then return :math:`\ERROR`.
+
+1. Else, return the :ref:`value <syntax-val>` :math:`\default_{valtype}`.
+
+.. math::
+   \begin{array}{lclll}
+   \F{val\_default}(t) &=& v && (\iff \default_t = v) \\
+   \F{val\_default}(t) &=& \ERROR && (\iff \default_t = \epsilon) \\
+   \end{array}
+
+
 .. index:: value type, external type, subtyping
 .. _embed-match-valtype:
 .. _embed-match-externtype:

document/js-api/index.bs

@@ -115,6 +115,7 @@ urlPrefix: https://webassembly.github.io/spec/core/; spec: WebAssembly; type: df
     text: global_read; url: appendix/embedding.html#embed-global-read
     text: global_write; url: appendix/embedding.html#embed-global-write
     text: ref_type; url: appendix/embedding.html#embed-ref-type
+    text: val_default; url: appendix/embedding.html#embed-val-default
     text: match_valtype; url: appendix/embedding.html#embed-match-valtype
     text: error; url: appendix/embedding.html#embed-error
     text: store; url: exec/runtime.html#syntax-store
@@ -764,6 +765,7 @@ Each {{Table}} object has a \[[Table]] internal slot, which is a [=table address
     1. If |maximum| is not empty and |maximum| < |initial|, throw a {{RangeError}} exception.
     1. If |value| is missing,
         1. Let |ref| be [=DefaultValue=](|elementType|).
+        1. Assert: |ref| is not [=error=].
     1. Otherwise,
         1. Let |ref| be [=?=] [=ToWebAssemblyValue=](|value|, |elementType|).
     1. Let |type| be the [=table type=] {[=table type|min=] |initial|, [=table type|max=] |maximum|} |elementType|.
@@ -781,6 +783,7 @@ Each {{Table}} object has a \[[Table]] internal slot, which is a [=table address
     1. Let (<var ignore>limits</var>, |elementType|) be [=table_type=](|tableaddr|).
     1. If |value| is missing,
         1. Let |ref| be [=DefaultValue=](|elementType|).
+        1. If |ref| is [=error=], throw a {{TypeError}} exception.
     1. Otherwise,
         1. Let |ref| be [=?=] [=ToWebAssemblyValue=](|value|, |elementType|).
     1. Let |result| be [=table_grow=](|store|, |tableaddr|, |delta|, |ref|).
@@ -814,6 +817,7 @@ Each {{Table}} object has a \[[Table]] internal slot, which is a [=table address
     1. Let (<var ignore>limits</var>, |elementType|) be [=table_type=](|tableaddr|).
     1. If |value| is missing,
         1. Let |ref| be [=DefaultValue=](|elementType|).
+        1. If |ref| is [=error=], throw a {{TypeError}} exception.
     1. Otherwise,
         1. Let |ref| be [=?=] [=ToWebAssemblyValue=](|value|, |elementType|).
     1. Let |store| be the [=surrounding agent=]'s [=associated store=].
@@ -890,13 +894,8 @@ which can be simultaneously referenced by multiple {{Instance}} objects. Each
 
 <div algorithm>
     The algorithm <dfn>DefaultValue</dfn>(|valuetype|) performs the following steps:
-    1. If |valuetype| equals [=i32=], return [=i32.const=] 0.
-    1. If |valuetype| equals [=i64=], return [=i64.const=] 0.
-    1. If |valuetype| equals [=f32=], return [=f32.const=] 0.
-    1. If |valuetype| equals [=f64=], return [=f64.const=] 0.
-    1. If |valuetype| equals [=funcref=], return [=ref.null=] [=funcref=].
     1. If |valuetype| equals [=externref=], return [=ToWebAssemblyValue=](undefined, |valuetype|).
-    1. Assert: This step is not reached.
+    1. Return [=val_default=](|valuetype|).
 </div>
 
 <div algorithm>
@@ -907,6 +906,7 @@ which can be simultaneously referenced by multiple {{Instance}} objects. Each
         1. Throw a {{TypeError}} exception.
     1. If |v| is missing,
         1. Let |value| be [=DefaultValue=](|valuetype|).
+        1. Assert: |value| is not [=error=].
     1. Otherwise,
         1. Let |value| be [=ToWebAssemblyValue=](|v|, |valuetype|).
     1. If |mutable| is true, let |globaltype| be [=var=] |valuetype|; otherwise, let |globaltype| be [=const=] |valuetype|.

test/js-api/gc/default-value.tentative.any.js

@@ -0,0 +1,43 @@
+// META: global=window,dedicatedworker,jsshell
+// META: script=/wasm/jsapi/wasm-module-builder.js
+
+let exports = {};
+setup(() => {
+  const builder = new WasmModuleBuilder();
+
+  builder.addTable(wasmRefType(kWasmAnyRef), 10, 20, [...wasmI32Const(42), ...GCInstr(kExprRefI31)])
+    .exportAs("tableAnyNonNullable");
+  builder.addTable(wasmRefNullType(kWasmAnyRef), 10, 20)
+    .exportAs("tableAnyNullable");
+
+  const buffer = builder.toBuffer();
+  const module = new WebAssembly.Module(buffer);
+  const instance = new WebAssembly.Instance(module, {});
+  exports = instance.exports;
+});
+
+test(() => {
+  exports.tableAnyNullable.grow(5);
+  for (let i = 0; i < 5; i++)
+    assert_equals(exports.tableAnyNullable.get(10 + i), null);
+}, "grow (nullable anyref)");
+
+test(() => {
+  assert_throws_js(TypeError, () => { exports.tableAnyNonNullable.grow(5); });
+  exports.tableAnyNonNullable.grow(5, "foo");
+  for (let i = 0; i < 5; i++)
+    assert_equals(exports.tableAnyNonNullable.get(10 + i), "foo");
+}, "grow (non-nullable anyref)");
+
+test(() => {
+  for (let i = 0; i < exports.tableAnyNullable.length; i++) {
+    exports.tableAnyNullable.set(i);
+    assert_equals(exports.tableAnyNullable.get(i), null);
+  }
+}, "set (nullable anyref)");
+
+test(() => {
+  for (let i = 0; i < exports.tableAnyNonNullable.length; i++) {
+    assert_throws_js(TypeError, () => { exports.tableAnyNonNullable.set(i); });
+  }
+}, "set (non-nullable anyref)");

test/js-api/gc/i31.tentative.any.js

@@ -11,7 +11,7 @@ setup(() => {
   builder
     .addFunction("makeI31", makeSig_r_x(i31Ref, kWasmI32))
     .addBody([kExprLocalGet, 0,
-              ...GCInstr(kExprI31New)])
+              ...GCInstr(kExprRefI31)])
     .exportFunc();
 
   builder
@@ -33,7 +33,7 @@ setup(() => {
     .exportFunc();
 
   builder
-    .addGlobal(i31NullableRef, true, [...wasmI32Const(0), ...GCInstr(kExprI31New)])
+    .addGlobal(i31NullableRef, true, [...wasmI32Const(0), ...GCInstr(kExprRefI31)])
   builder
     .addExportOfKind("i31Global", kExternalGlobal, 0);
 

test/js-api/wasm-module-builder.js

@@ -456,7 +456,7 @@ let kExprBrOnCast = 0x18;
 let kExprBrOnCastFail = 0x19;
 let kExprExternInternalize = 0x1a;
 let kExprExternExternalize = 0x1b;
-let kExprI31New = 0x1c;
+let kExprRefI31 = 0x1c;
 let kExprI31GetS = 0x1d;
 let kExprI31GetU = 0x1e;
 
@@ -1199,6 +1199,10 @@ class WasmModuleBuilder {
       binary.emit_section(kTableSectionCode, section => {
         section.emit_u32v(wasm.tables.length);
         for (let table of wasm.tables) {
+          if (table.has_init) {
+            section.emit_u8(0x40);  // "has initializer"
+            section.emit_u8(0x00);  // Reserved byte.
+          }
           section.emit_type(table.type);
           section.emit_u8(table.has_max);
           section.emit_u32v(table.initial_size);