Bug 1285438 - Baldr: remove magic empty string export logic (r=bbouvier)

MozReview-Commit-ID: 5FgMIQiBozj

--HG--
extra : rebase_source : 86b0b12e7618f950c576b5e77d47cd0abf613d0b

js/src/asmjs/WasmInstance.cpp

@@ -384,48 +384,34 @@ NewExportedFunction(JSContext* cx, Handle<WasmInstanceObject*> instanceObj, uint
 static bool
 CreateExportObject(JSContext* cx,
                    HandleWasmInstanceObject instanceObj,
-                   HandleObject memoryObj,
+                   HandleWasmMemoryObject memoryObj,
                    const ExportMap& exportMap,
-                   const ExportVector& exports,
+                   const Metadata& metadata,
                    MutableHandleObject exportObj)
 {
     MOZ_ASSERT(exportMap.fieldNames.length() == exportMap.fieldsToExports.length());
 
-    for (size_t fieldIndex = 0; fieldIndex < exportMap.fieldNames.length(); fieldIndex++) {
-        const char* fieldName = exportMap.fieldNames[fieldIndex].get();
-        if (!*fieldName) {
-            MOZ_ASSERT(!exportObj);
-            uint32_t exportIndex = exportMap.fieldsToExports[fieldIndex];
-            if (exportIndex == MemoryExport) {
-                MOZ_ASSERT(memoryObj);
-                exportObj.set(memoryObj);
-            } else {
-                exportObj.set(NewExportedFunction(cx, instanceObj, exportIndex));
-                if (!exportObj)
-                    return false;
-            }
-            break;
-        }
+    if (metadata.isAsmJS() &&
+        exportMap.fieldNames.length() == 1 &&
+        strlen(exportMap.fieldNames[0].get()) == 0)
+    {
+        exportObj.set(NewExportedFunction(cx, instanceObj, 0));
+        return !!exportObj;
     }
 
+    exportObj.set(JS_NewPlainObject(cx));
+    if (!exportObj)
+        return false;
+
     Rooted<ValueVector> vals(cx, ValueVector(cx));
-    for (size_t exportIndex = 0; exportIndex < exports.length(); exportIndex++) {
+    for (size_t exportIndex = 0; exportIndex < metadata.exports.length(); exportIndex++) {
         JSFunction* fun = NewExportedFunction(cx, instanceObj, exportIndex);
         if (!fun || !vals.append(ObjectValue(*fun)))
             return false;
     }
 
-    if (!exportObj) {
-        exportObj.set(JS_NewPlainObject(cx));
-        if (!exportObj)
-            return false;
-    }
-
     for (size_t fieldIndex = 0; fieldIndex < exportMap.fieldNames.length(); fieldIndex++) {
         const char* fieldName = exportMap.fieldNames[fieldIndex].get();
-        if (!*fieldName)
-            continue;
-
         JSAtom* atom = AtomizeUTF8Chars(cx, fieldName, strlen(fieldName));
         if (!atom)
             return false;
@@ -433,10 +419,14 @@ CreateExportObject(JSContext* cx,
         RootedId id(cx, AtomToId(atom));
         RootedValue val(cx);
         uint32_t exportIndex = exportMap.fieldsToExports[fieldIndex];
-        if (exportIndex == MemoryExport)
-            val = ObjectValue(*memoryObj);
-        else
+        if (exportIndex == MemoryExport) {
+            if (metadata.assumptions.newFormat)
+                val = ObjectValue(*memoryObj);
+            else
+                val = ObjectValue(memoryObj->buffer());
+        } else {
             val = vals[exportIndex];
+        }
 
         if (!JS_DefinePropertyById(cx, exportObj, id, val, JSPROP_ENUMERATE))
             return false;
@@ -499,14 +489,8 @@ Instance::create(JSContext* cx,
 
     // Create the export object.
 
-    RootedObject memoryObj(cx);
-    if (metadata.assumptions.newFormat)
-        memoryObj = memory;
-    else
-        memoryObj = memory ? &memory->buffer() : nullptr;
-
     RootedObject exportObj(cx);
-    if (!CreateExportObject(cx, instanceObj, memoryObj, exportMap, metadata.exports, &exportObj))
+    if (!CreateExportObject(cx, instanceObj, memory, exportMap, metadata, &exportObj))
         return false;
 
     // Attach the export object to the instance object.

js/src/jit-test/lib/wasm.js

@@ -4,7 +4,10 @@ if (!wasmIsSupported())
 load(libdir + "asserts.js");
 
 function wasmEvalText(str, imports) {
-    return Wasm.instantiateModule(wasmTextToBinary(str), imports).exports;
+    var exports = Wasm.instantiateModule(wasmTextToBinary(str), imports).exports;
+    if (Object.keys(exports).length == 1 && exports[""])
+        return exports[""];
+    return exports;
 }
 
 function mismatchError(actual, expect) {

js/src/jit-test/tests/wasm/basic.js

@@ -10,12 +10,6 @@ assertEq(Object.getOwnPropertyNames(o).length, 0);
 var o = wasmEvalText('(module (func))');
 assertEq(Object.getOwnPropertyNames(o).length, 0);
 
-var o = wasmEvalText('(module (func) (export "" 0))');
-assertEq(typeof o, "function");
-assertEq(o.name, "wasm-function[0]");
-assertEq(o.length, 0);
-assertEq(o(), undefined);
-
 var o = wasmEvalText('(module (func) (export "a" 0))');
 var names = Object.getOwnPropertyNames(o);
 assertEq(names.length, 1);
@@ -30,21 +24,6 @@ assertEq(desc.enumerable, true);
 assertEq(desc.configurable, true);
 assertEq(desc.value(), undefined);
 
-var o = wasmEvalText('(module (func) (func) (export "" 0) (export "a" 1))');
-assertEq(typeof o, "function");
-assertEq(o.name, "wasm-function[0]");
-assertEq(o.length, 0);
-assertEq(o(), undefined);
-var desc = Object.getOwnPropertyDescriptor(o, 'a');
-assertEq(typeof desc.value, "function");
-assertEq(desc.value.name, "wasm-function[1]");
-assertEq(desc.value.length, 0);
-assertEq(desc.value(), undefined);
-assertEq(desc.writable, true);
-assertEq(desc.enumerable, true);
-assertEq(desc.configurable, true);
-assertEq(desc.value(), undefined);
-
 wasmEvalText('(module (func) (func) (export "a" 0))');
 wasmEvalText('(module (func) (func) (export "a" 1))');
 wasmEvalText('(module (func $a) (func $b) (export "a" $a) (export "b" $b))');

js/src/jit-test/tests/wasm/import-export.js

@@ -151,6 +151,12 @@ assertEq(Object.keys(e).join(), "bar,foo");
 assertEq(e.foo(), undefined);
 assertEq(e.bar.buffer.byteLength, 64*1024);
 
+var code = textToBinary('(module (memory 1 1) (export "" memory))');
+var e = new Instance(new Module(code)).exports;
+assertEq(Object.keys(e).length, 1);
+assertEq(String(Object.keys(e)), "");
+assertEq(e[""] instanceof Memory, true);
+
 // Re-exports:
 
 var code = textToBinary('(module (import "a" "b" (memory 1 1)) (export "foo" memory) (export "bar" memory))');

js/src/jit-test/tests/wasm/spec.js

@@ -215,7 +215,7 @@ function exec(e) {
 
     if (exprName === "module") {
         let moduleText = e.toString();
-        module = wasmEvalText(moduleText, imports);
+        module = Wasm.instantiateModule(wasmTextToBinary(moduleText), imports).exports;
         return;
     }
 
@@ -231,9 +231,6 @@ function exec(e) {
 
         if (typeof module[name] === "function") {
             fn = module[name];
-        } else if (name === "") {
-            fn = module;
-            assert(typeof fn === "function", "Default exported function not found: " + e);
         } else {
             assert(false, "Exported function not found: " + e);
         }