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<dt>Revision</dt> <dd><a href="http://trac.webkit.org/projects/webkit/changeset/211070">211070</a></dd>
<dt>Author</dt> <dd>sbarati@apple.com</dd>
<dt>Date</dt> <dd>2017-01-23 16:15:21 -0800 (Mon, 23 Jan 2017)</dd>
</dl>
<h3>Log Message</h3>
<pre>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):</pre>
<h3>Modified Paths</h3>
<ul>
<li><a href="#trunkJSTestsChangeLog">trunk/JSTests/ChangeLog</a></li>
<li><a href="#trunkSourceJavaScriptCoreChangeLog">trunk/Source/JavaScriptCore/ChangeLog</a></li>
<li><a href="#trunkSourceJavaScriptCoredfgDFGOperationscpp">trunk/Source/JavaScriptCore/dfg/DFGOperations.cpp</a></li>
<li><a href="#trunkSourceJavaScriptCorejsccpp">trunk/Source/JavaScriptCore/jsc.cpp</a></li>
<li><a href="#trunkSourceJavaScriptCoreruntimeCommonSlowPathscpp">trunk/Source/JavaScriptCore/runtime/CommonSlowPaths.cpp</a></li>
<li><a href="#trunkSourceJavaScriptCoreruntimeJSArrayh">trunk/Source/JavaScriptCore/runtime/JSArray.h</a></li>
<li><a href="#trunkSourceJavaScriptCoreruntimeJSArrayInlinesh">trunk/Source/JavaScriptCore/runtime/JSArrayInlines.h</a></li>
</ul>
<h3>Added Paths</h3>
<ul>
<li><a href="#trunkJSTestsstressspreadconsultscorrectglobalobjectjs">trunk/JSTests/stress/spread-consults-correct-global-object.js</a></li>
<li><a href="#trunkJSTestsstressspreadcorrectglobalobjectonexceptionjs">trunk/JSTests/stress/spread-correct-global-object-on-exception.js</a></li>
</ul>
</div>
<div id="patch">
<h3>Diff</h3>
<a id="trunkJSTestsChangeLog"></a>
<div class="modfile"><h4>Modified: trunk/JSTests/ChangeLog (211069 => 211070)</h4>
<pre class="diff"><span>
<span class="info">--- trunk/JSTests/ChangeLog 2017-01-24 00:01:13 UTC (rev 211069)
+++ trunk/JSTests/ChangeLog 2017-01-24 00:15:21 UTC (rev 211070)
</span><span class="lines">@@ -1,3 +1,20 @@
</span><ins>+2017-01-23 Saam Barati <sbarati@apple.com>
+
+ 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.
+
+ * 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):
+
</ins><span class="cx"> 2017-01-21 Yusuke Suzuki <utatane.tea@gmail.com>
</span><span class="cx">
</span><span class="cx"> dynamic import is ambiguous with import declaration at module code
</span></span></pre></div>
<a id="trunkJSTestsstressspreadconsultscorrectglobalobjectjs"></a>
<div class="addfile"><h4>Added: trunk/JSTests/stress/spread-consults-correct-global-object.js (0 => 211070)</h4>
<pre class="diff"><span>
<span class="info">--- trunk/JSTests/stress/spread-consults-correct-global-object.js (rev 0)
+++ trunk/JSTests/stress/spread-consults-correct-global-object.js 2017-01-24 00:15:21 UTC (rev 211070)
</span><span class="lines">@@ -0,0 +1,18 @@
</span><ins>+function assert(b) {
+ if (!b)
+ throw new Error("Bad assertion");
+}
+function spread(a) {
+ return [...a];
+}
+noInline(spread);
+
+const foo = {};
+
+let secondGlobalObject = createGlobalObject();
+secondGlobalObject.Array.prototype[0] = foo;
+let x = secondGlobalObject.Function("return [, 20];")();
+let result = spread(x);
+assert(result.length === 2);
+assert(result[0] === foo);
+assert(result[1] === 20);
</ins></span></pre></div>
<a id="trunkJSTestsstressspreadcorrectglobalobjectonexceptionjs"></a>
<div class="addfile"><h4>Added: trunk/JSTests/stress/spread-correct-global-object-on-exception.js (0 => 211070)</h4>
<pre class="diff"><span>
<span class="info">--- trunk/JSTests/stress/spread-correct-global-object-on-exception.js (rev 0)
+++ trunk/JSTests/stress/spread-correct-global-object-on-exception.js 2017-01-24 00:15:21 UTC (rev 211070)
</span><span class="lines">@@ -0,0 +1,43 @@
</span><ins>+function assert(b) {
+ if (!b)
+ throw new Error("Bad assertion");
+}
+function spread(a) {
+ return [...a];
+}
+noInline(spread);
+
+const objectText = `
+ let o = {
+ [Symbol.iterator]() {
+ return {
+ next() {
+ return {done: true};
+ }
+ };
+ }
+ };
+ o;
+`;
+
+let o = eval(objectText);
+for (let i = 0; i < 1000; i++) {
+ if (i % 23 === 0)
+ o = eval(objectText);
+ spread(o);
+}
+
+let myGlobalObject = globalObjectForObject(new Object);
+
+let secondGlobalObject = createGlobalObject();
+let o2 = secondGlobalObject.Function("return {};")();
+
+let error = null;
+try {
+ spread(o2);
+} catch(e) {
+ error = e;
+}
+
+assert(error);
+assert(globalObjectForObject(error) === myGlobalObject);
</ins></span></pre></div>
<a id="trunkSourceJavaScriptCoreChangeLog"></a>
<div class="modfile"><h4>Modified: trunk/Source/JavaScriptCore/ChangeLog (211069 => 211070)</h4>
<pre class="diff"><span>
<span class="info">--- trunk/Source/JavaScriptCore/ChangeLog 2017-01-24 00:01:13 UTC (rev 211069)
+++ trunk/Source/JavaScriptCore/ChangeLog 2017-01-24 00:15:21 UTC (rev 211070)
</span><span class="lines">@@ -1,3 +1,42 @@
</span><ins>+2017-01-23 Saam Barati <sbarati@apple.com>
+
+ 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.
+
+ 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):
+
</ins><span class="cx"> 2017-01-22 Filip Pizlo <fpizlo@apple.com>
</span><span class="cx">
</span><span class="cx"> Land the stochastic space-time scheduler disabled
</span></span></pre></div>
<a id="trunkSourceJavaScriptCoredfgDFGOperationscpp"></a>
<div class="modfile"><h4>Modified: trunk/Source/JavaScriptCore/dfg/DFGOperations.cpp (211069 => 211070)</h4>
<pre class="diff"><span>
<span class="info">--- trunk/Source/JavaScriptCore/dfg/DFGOperations.cpp 2017-01-24 00:01:13 UTC (rev 211069)
+++ trunk/Source/JavaScriptCore/dfg/DFGOperations.cpp 2017-01-24 00:15:21 UTC (rev 211070)
</span><span class="lines">@@ -47,6 +47,7 @@
</span><span class="cx"> #include "Interpreter.h"
</span><span class="cx"> #include "JIT.h"
</span><span class="cx"> #include "JITExceptions.h"
</span><ins>+#include "JSArrayInlines.h"
</ins><span class="cx"> #include "JSCInlines.h"
</span><span class="cx"> #include "JSFixedArray.h"
</span><span class="cx"> #include "JSGenericTypedArrayViewConstructorInlines.h"
</span><span class="lines">@@ -1984,19 +1985,18 @@
</span><span class="cx">
</span><span class="cx"> auto throwScope = DECLARE_THROW_SCOPE(vm);
</span><span class="cx">
</span><del>- JSGlobalObject* globalObject = iterable->structure(vm)->globalObject();
- if (!globalObject)
- globalObject = exec->lexicalGlobalObject();
-
- if (isJSArray(iterable) && globalObject->isArrayIteratorProtocolFastAndNonObservable()) {
</del><ins>+ if (isJSArray(iterable)) {
</ins><span class="cx"> JSArray* array = jsCast<JSArray*>(iterable);
</span><del>- throwScope.release();
- return JSFixedArray::createFromArray(exec, vm, array);
</del><ins>+ if (array->isIteratorProtocolFastAndNonObservable()) {
+ throwScope.release();
+ return JSFixedArray::createFromArray(exec, vm, array);
+ }
</ins><span class="cx"> }
</span><span class="cx">
</span><span class="cx"> // FIXME: we can probably make this path faster by having our caller JS code call directly into
</span><span class="cx"> // the iteration protocol builtin: https://bugs.webkit.org/show_bug.cgi?id=164520
</span><span class="cx">
</span><ins>+ JSGlobalObject* globalObject = exec->lexicalGlobalObject();
</ins><span class="cx"> JSArray* array;
</span><span class="cx"> {
</span><span class="cx"> JSFunction* iterationFunction = globalObject->iteratorProtocolFunction();
</span><span class="lines">@@ -2022,7 +2022,7 @@
</span><span class="cx">
</span><span class="cx"> ASSERT(isJSArray(cell));
</span><span class="cx"> JSArray* array = jsCast<JSArray*>(cell);
</span><del>- ASSERT(array->globalObject()->isArrayIteratorProtocolFastAndNonObservable());
</del><ins>+ ASSERT(array->isIteratorProtocolFastAndNonObservable());
</ins><span class="cx">
</span><span class="cx"> return JSFixedArray::createFromArray(exec, vm, array);
</span><span class="cx"> }
</span></span></pre></div>
<a id="trunkSourceJavaScriptCorejsccpp"></a>
<div class="modfile"><h4>Modified: trunk/Source/JavaScriptCore/jsc.cpp (211069 => 211070)</h4>
<pre class="diff"><span>
<span class="info">--- trunk/Source/JavaScriptCore/jsc.cpp 2017-01-24 00:01:13 UTC (rev 211069)
+++ trunk/Source/JavaScriptCore/jsc.cpp 2017-01-24 00:15:21 UTC (rev 211070)
</span><span class="lines">@@ -1011,6 +1011,7 @@
</span><span class="cx"> static EncodedJSValue JSC_HOST_CALL functionSetRandomSeed(ExecState*);
</span><span class="cx"> static EncodedJSValue JSC_HOST_CALL functionIsRope(ExecState*);
</span><span class="cx"> static EncodedJSValue JSC_HOST_CALL functionCallerSourceOrigin(ExecState*);
</span><ins>+static EncodedJSValue JSC_HOST_CALL functionGlobalObjectForObject(ExecState*);
</ins><span class="cx">
</span><span class="cx"> struct Script {
</span><span class="cx"> enum class StrictMode {
</span><span class="lines">@@ -1235,6 +1236,8 @@
</span><span class="cx"> addFunction(vm, "isRope", functionIsRope, 1);
</span><span class="cx"> addFunction(vm, "callerSourceOrigin", functionCallerSourceOrigin, 0);
</span><span class="cx">
</span><ins>+ addFunction(vm, "globalObjectForObject", functionGlobalObjectForObject, 1);
+
</ins><span class="cx"> addFunction(vm, "is32BitPlatform", functionIs32BitPlatform, 0);
</span><span class="cx">
</span><span class="cx"> addFunction(vm, "loadModule", functionLoadModule, 1);
</span><span class="lines">@@ -2155,6 +2158,15 @@
</span><span class="cx"> return JSValue::encode(jsString(state, sourceOrigin.string()));
</span><span class="cx"> }
</span><span class="cx">
</span><ins>+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);
+}
+
</ins><span class="cx"> EncodedJSValue JSC_HOST_CALL functionReadline(ExecState* exec)
</span><span class="cx"> {
</span><span class="cx"> Vector<char, 256> line;
</span></span></pre></div>
<a id="trunkSourceJavaScriptCoreruntimeCommonSlowPathscpp"></a>
<div class="modfile"><h4>Modified: trunk/Source/JavaScriptCore/runtime/CommonSlowPaths.cpp (211069 => 211070)</h4>
<pre class="diff"><span>
<span class="info">--- trunk/Source/JavaScriptCore/runtime/CommonSlowPaths.cpp 2017-01-24 00:01:13 UTC (rev 211069)
+++ trunk/Source/JavaScriptCore/runtime/CommonSlowPaths.cpp 2017-01-24 00:15:21 UTC (rev 211070)
</span><span class="lines">@@ -43,6 +43,7 @@
</span><span class="cx"> #include "Interpreter.h"
</span><span class="cx"> #include "IteratorOperations.h"
</span><span class="cx"> #include "JIT.h"
</span><ins>+#include "JSArrayInlines.h"
</ins><span class="cx"> #include "JSCInlines.h"
</span><span class="cx"> #include "JSCJSValue.h"
</span><span class="cx"> #include "JSFixedArray.h"
</span><span class="lines">@@ -1034,16 +1035,18 @@
</span><span class="cx">
</span><span class="cx"> JSValue iterable = OP_C(2).jsValue();
</span><span class="cx">
</span><del>- JSGlobalObject* globalObject = exec->lexicalGlobalObject();
-
- if (iterable.isCell() && isJSArray(iterable.asCell()) && globalObject->isArrayIteratorProtocolFastAndNonObservable()) {
- // JSFixedArray::createFromArray does not consult the prototype chain,
- // so we must be sure that not consulting the prototype chain would
- // produce the same value during iteration.
</del><ins>+ if (iterable.isCell() && isJSArray(iterable.asCell())) {
</ins><span class="cx"> JSArray* array = jsCast<JSArray*>(iterable);
</span><del>- RETURN(JSFixedArray::createFromArray(exec, vm, array));
</del><ins>+ if (array->isIteratorProtocolFastAndNonObservable()) {
+ // JSFixedArray::createFromArray does not consult the prototype chain,
+ // so we must be sure that not consulting the prototype chain would
+ // produce the same value during iteration.
+ RETURN(JSFixedArray::createFromArray(exec, vm, array));
+ }
</ins><span class="cx"> }
</span><span class="cx">
</span><ins>+ JSGlobalObject* globalObject = exec->lexicalGlobalObject();
+
</ins><span class="cx"> JSArray* array;
</span><span class="cx"> {
</span><span class="cx"> JSFunction* iterationFunction = globalObject->iteratorProtocolFunction();
</span></span></pre></div>
<a id="trunkSourceJavaScriptCoreruntimeJSArrayh"></a>
<div class="modfile"><h4>Modified: trunk/Source/JavaScriptCore/runtime/JSArray.h (211069 => 211070)</h4>
<pre class="diff"><span>
<span class="info">--- trunk/Source/JavaScriptCore/runtime/JSArray.h 2017-01-24 00:01:13 UTC (rev 211069)
+++ trunk/Source/JavaScriptCore/runtime/JSArray.h 2017-01-24 00:15:21 UTC (rev 211070)
</span><span class="lines">@@ -150,6 +150,8 @@
</span><span class="cx"> JS_EXPORT_PRIVATE void fillArgList(ExecState*, MarkedArgumentBuffer&);
</span><span class="cx"> JS_EXPORT_PRIVATE void copyToArguments(ExecState*, VirtualRegister firstElementDest, unsigned offset, unsigned length);
</span><span class="cx">
</span><ins>+ bool isIteratorProtocolFastAndNonObservable();
+
</ins><span class="cx"> static Structure* createStructure(VM& vm, JSGlobalObject* globalObject, JSValue prototype, IndexingType indexingType)
</span><span class="cx"> {
</span><span class="cx"> return Structure::create(vm, globalObject, prototype, TypeInfo(ArrayType, StructureFlags), info(), indexingType);
</span></span></pre></div>
<a id="trunkSourceJavaScriptCoreruntimeJSArrayInlinesh"></a>
<div class="modfile"><h4>Modified: trunk/Source/JavaScriptCore/runtime/JSArrayInlines.h (211069 => 211070)</h4>
<pre class="diff"><span>
<span class="info">--- trunk/Source/JavaScriptCore/runtime/JSArrayInlines.h 2017-01-24 00:01:13 UTC (rev 211069)
+++ trunk/Source/JavaScriptCore/runtime/JSArrayInlines.h 2017-01-24 00:15:21 UTC (rev 211070)
</span><span class="lines">@@ -93,4 +93,9 @@
</span><span class="cx"> return lengthValue.toLength(exec);
</span><span class="cx"> }
</span><span class="cx">
</span><ins>+ALWAYS_INLINE bool JSArray::isIteratorProtocolFastAndNonObservable()
+{
+ return globalObject()->isArrayIteratorProtocolFastAndNonObservable();
+}
+
</ins><span class="cx"> } // namespace JSC
</span></span></pre>
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