Changeset 211070 in webkit for trunk/Source/JavaScriptCore/jsc.cpp

Timestamp:

Jan 23, 2017, 4:15:21 PM (8 years ago)

Author:

[email protected]

Message:

​https://bugs.webkit.org/show_bug.cgi?id=167247
JSC: operationSpreadGeneric uses the wrong global object for the builtin function and slow_path_spread consults the wrong global object to prove if the iterator protocol is unobservable
<rdar://problem/30121809>

Reviewed by Filip Pizlo.

JSTests:

• stress/spread-consults-correct-global-object.js: Added.

(assert):
(spread):

• stress/spread-correct-global-object-on-exception.js: Added.

(assert):
(spread):
(const.objectText.let.o.Symbol.iterator):
(catch):

Source/JavaScriptCore:

There were two bugs in the different tiers with respect to how
spread handled global objects.

The first was in the LLInt/baseline inside slow_path_spread:

We consulted the lexical global object instead of the thing we're
spreading's global object to determine if the array iterator protocol
is unobservable. This is wrong if the incoming array is from a different
global object. We must consult the incoming array's global object
to determine if it can be spread using the fast path.

The second was in operationSpreadGeneric in the DFG/FTL:

We were always using the incoming array's global object, even
when going down the slow path. This is wrong because we were
fetching the builtin iteration function helper from the incoming
array's global object, which meant that if the iterator function
were to throw an exception, it could leak objects from a different
global object. We should be executing the iterator function with
the lexical global object.

• dfg/DFGOperations.cpp:
• jsc.cpp:

(GlobalObject::finishCreation):
(functionGlobalObjectForObject):

• runtime/CommonSlowPaths.cpp:

(JSC::SLOW_PATH_DECL):

• runtime/JSArray.h:
• runtime/JSArrayInlines.h:

(JSC::JSArray::isIteratorProtocolFastAndNonObservable):

File:

• trunk/Source/JavaScriptCore/jsc.cpp (modified) (3 diffs)

trunk/Source/JavaScriptCore/jsc.cpp

@@ -1012 +1012 @@
 static EncodedJSValue JSC_HOST_CALL functionIsRope(ExecState*);
 static EncodedJSValue JSC_HOST_CALL functionCallerSourceOrigin(ExecState*);
+static EncodedJSValue JSC_HOST_CALL functionGlobalObjectForObject(ExecState*);
 
 struct Script {
@@ -1235 +1236 @@
         addFunction(vm, "isRope", functionIsRope, 1);
         addFunction(vm, "callerSourceOrigin", functionCallerSourceOrigin, 0);
+
+        addFunction(vm, "globalObjectForObject", functionGlobalObjectForObject, 1);
 
         addFunction(vm, "is32BitPlatform", functionIs32BitPlatform, 0);
@@ -2154 +2157 @@
         return JSValue::encode(jsNull());
     return JSValue::encode(jsString(state, sourceOrigin.string()));
+}
+
+EncodedJSValue JSC_HOST_CALL functionGlobalObjectForObject(ExecState* exec)
+{
+    JSValue value = exec->argument(0);
+    RELEASE_ASSERT(value.isObject());
+    JSGlobalObject* globalObject = jsCast<JSObject*>(value)->globalObject();
+    RELEASE_ASSERT(globalObject);
+    return JSValue::encode(globalObject);
 }