Bug 1441765 - Guard WebAssembly.Global on EARLY_BETA_OR_EARLIER. r=luke

--HG--
extra : rebase_source : d02e3cddbce369e0e098bb9ad2fd641677697cd0
extra : histedit_source : 86ea4d95421f7b5aa057ed49c0c5729dc26d996e

js/src/moz.build

@@ -652,11 +652,13 @@ if CONFIG['NIGHTLY_BUILD']:
     DEFINES['ENABLE_WASM_SATURATING_TRUNC_OPS'] = True
     DEFINES['ENABLE_WASM_SIGNEXTEND_OPS'] = True
     DEFINES['ENABLE_WASM_THREAD_OPS'] = True
-    # An experiment we want to run on Nightly: Can we change the JS
-    # representation of an exported global from the global's value
-    # to an instance of WebAssembly.Global without breaking existing
-    # wasm content?
-    DEFINES['ENABLE_WASM_GLOBAL'] = True
+
+# An experiment we want to run on Nightly and early Beta: Can we change the JS
+# representation of an exported global from the global's value to an instance
+# of WebAssembly.Global without breaking existing wasm content?
+#
+# Additionally guarded by EARLY_BETA_OR_EARLIER in the code.
+DEFINES['ENABLE_WASM_GLOBAL'] = True
 
 if CONFIG['JS_BUILD_BINAST']:
     # Using SOURCES as UNIFIED_SOURCES causes mysterious bugs on 32-bit platforms.

js/src/wasm/WasmJS.cpp

@@ -253,7 +253,7 @@ GetImports(JSContext* cx,
             MOZ_ASSERT(global.importIndex() == globalIndex - 1);
             MOZ_ASSERT(!global.isMutable());
 
-#ifdef ENABLE_WASM_GLOBAL
+#if defined(ENABLE_WASM_GLOBAL) && defined(EARLY_BETA_OR_EARLIER)
             if (v.isObject() && v.toObject().is<WasmGlobalObject>())
                 v.set(v.toObject().as<WasmGlobalObject>().value());
 #endif
@@ -1935,7 +1935,7 @@ WasmTableObject::table() const
 // ============================================================================
 // WebAssembly.global class and methods
 
-#ifdef ENABLE_WASM_GLOBAL
+#if defined(ENABLE_WASM_GLOBAL) && defined(EARLY_BETA_OR_EARLIER)
 
 const ClassOps WasmGlobalObject::classOps_ =
 {
@@ -2128,7 +2128,7 @@ WasmGlobalObject::value() const
     return getReservedSlot(VALUE_SLOT);
 }
 
-#endif // ENABLE_WASM_GLOBAL
+#endif // ENABLE_WASM_GLOBAL && EARLY_BETA_OR_EARLIER
 
 // ============================================================================
 // WebAssembly class and static methods
@@ -2968,7 +2968,7 @@ js::InitWebAssemblyClass(JSContext* cx, HandleObject obj)
         return nullptr;
 
     RootedObject moduleProto(cx), instanceProto(cx), memoryProto(cx), tableProto(cx);
-#ifdef ENABLE_WASM_GLOBAL
+#if defined(ENABLE_WASM_GLOBAL) && defined(EARLY_BETA_OR_EARLIER)
     RootedObject globalProto(cx);
 #endif
     if (!InitConstructor<WasmModuleObject>(cx, wasm, "Module", &moduleProto))
@@ -2979,7 +2979,7 @@ js::InitWebAssemblyClass(JSContext* cx, HandleObject obj)
         return nullptr;
     if (!InitConstructor<WasmTableObject>(cx, wasm, "Table", &tableProto))
         return nullptr;
-#ifdef ENABLE_WASM_GLOBAL
+#if defined(ENABLE_WASM_GLOBAL) && defined(EARLY_BETA_OR_EARLIER)
     if (!InitConstructor<WasmGlobalObject>(cx, wasm, "Global", &globalProto))
         return nullptr;
 #endif
@@ -3002,7 +3002,7 @@ js::InitWebAssemblyClass(JSContext* cx, HandleObject obj)
     global->setPrototype(JSProto_WasmInstance, ObjectValue(*instanceProto));
     global->setPrototype(JSProto_WasmMemory, ObjectValue(*memoryProto));
     global->setPrototype(JSProto_WasmTable, ObjectValue(*tableProto));
-#ifdef ENABLE_WASM_GLOBAL
+#if defined(ENABLE_WASM_GLOBAL) && defined(EARLY_BETA_OR_EARLIER)
     global->setPrototype(JSProto_WasmGlobal, ObjectValue(*globalProto));
 #endif
     global->setConstructor(JSProto_WebAssembly, ObjectValue(*wasm));

js/src/wasm/WasmJS.h

@@ -285,7 +285,7 @@ class WasmTableObject : public NativeObject
     wasm::Table& table() const;
 };
 
-#ifdef ENABLE_WASM_GLOBAL
+#if defined(ENABLE_WASM_GLOBAL) && defined(EARLY_BETA_OR_EARLIER)
 
 // The class of WebAssembly.Global.  A WasmGlobalObject holds either the value
 // of an immutable wasm global or the cell of a mutable wasm global.
@@ -319,7 +319,7 @@ class WasmGlobalObject : public NativeObject
     Value value() const;
 };
 
-#endif // ENABLE_WASM_GLOBAL
+#endif // ENABLE_WASM_GLOBAL && EARLY_BETA_OR_EARLIER
 
 } // namespace js
 

js/src/wasm/WasmModule.cpp

@@ -1016,7 +1016,7 @@ GetGlobalExport(JSContext* cx, const GlobalDescVector& globals, uint32_t globalI
 
     ToJSValue(val, jsval);
 
-#ifdef ENABLE_WASM_GLOBAL
+#if defined(ENABLE_WASM_GLOBAL) && defined(EARLY_BETA_OR_EARLIER)
     Rooted<WasmGlobalObject*> go(cx, WasmGlobalObject::create(cx, ValType::I32, false, jsval));
     if (!go)
         return false;