Title: [200729] branches/safari-601-branch/Source/_javascript_Core
Revision
200729
Author
matthew_han...@apple.com
Date
2016-05-11 18:31:47 -0700 (Wed, 11 May 2016)

Log Message

Merge r196524. rdar://problem/26228552

Modified Paths

Diff

Modified: branches/safari-601-branch/Source/_javascript_Core/ChangeLog (200728 => 200729)


--- branches/safari-601-branch/Source/_javascript_Core/ChangeLog	2016-05-12 01:31:45 UTC (rev 200728)
+++ branches/safari-601-branch/Source/_javascript_Core/ChangeLog	2016-05-12 01:31:47 UTC (rev 200729)
@@ -1,3 +1,23 @@
+2016-05-11  Matthew Hanson  <matthew_han...@apple.com>
+
+        Merge r196524. rdar://problem/26228552
+
+    2016-02-12  Filip Pizlo  <fpi...@apple.com>
+
+            JSObject::putByIndexBeyondVectorLengthWithoutAttributes needs to go to the sparse map based on MAX_STORAGE_VECTOR_INDEX
+            https://bugs.webkit.org/show_bug.cgi?id=154201
+            rdar://problem/24291387
+
+            Reviewed by Saam Barati.
+
+            I decided against adding a test for this, because it runs for a very long time.
+
+            * runtime/JSObject.cpp:
+            (JSC::JSObject::putByIndexBeyondVectorLengthWithoutAttributes): Fix the bug.
+            * runtime/StringPrototype.cpp:
+            (JSC::stringProtoFuncSplit): Fix a related bug: if this code creates an array that would have
+                hit the above bug, then it would probably manifest as a spin or as swapping.
+
 2016-03-24  Matthew Hanson  <matthew_han...@apple.com>
 
         Merge r198592. rdar://problem/25332806

Modified: branches/safari-601-branch/Source/_javascript_Core/runtime/JSObject.cpp (200728 => 200729)


--- branches/safari-601-branch/Source/_javascript_Core/runtime/JSObject.cpp	2016-05-12 01:31:45 UTC (rev 200728)
+++ branches/safari-601-branch/Source/_javascript_Core/runtime/JSObject.cpp	2016-05-12 01:31:47 UTC (rev 200729)
@@ -1932,7 +1932,7 @@
     
     VM& vm = exec->vm();
     
-    if (i >= MAX_ARRAY_INDEX - 1
+    if (i > MAX_STORAGE_VECTOR_INDEX
         || (i >= MIN_SPARSE_ARRAY_INDEX
             && !isDenseEnoughForVector(i, countElements<indexingShape>(butterfly())))
         || indexIsSufficientlyBeyondLengthForSparseMap(i, m_butterfly->vectorLength())) {

Modified: branches/safari-601-branch/Source/_javascript_Core/runtime/StringPrototype.cpp (200728 => 200729)


--- branches/safari-601-branch/Source/_javascript_Core/runtime/StringPrototype.cpp	2016-05-12 01:31:45 UTC (rev 200728)
+++ branches/safari-601-branch/Source/_javascript_Core/runtime/StringPrototype.cpp	2016-05-12 01:31:47 UTC (rev 200729)
@@ -1182,8 +1182,23 @@
 
             // 3. Increment lengthA by 1.
             // 4. If lengthA == lim, return A.
-            if (++resultLength == limit)
+            ++resultLength;
+            if (resultLength == limit)
                 return JSValue::encode(result);
+            if (resultLength >= MAX_STORAGE_VECTOR_INDEX) {
+                // Let's consider what's best for users here. We're about to increase the length of
+                // the split array beyond the maximum length that we can support efficiently. This
+                // will cause us to use a HashMap for the new entries after this point. That's going
+                // to result in a very long running time of this function and very large memory
+                // usage. In my experiments, JSC will sit spinning for minutes after getting here and
+                // it was using >4GB of memory and eventually grew to 8GB. It kept running without
+                // finishing until I killed it. That's probably not what the user wanted. The user,
+                // or the program that the user is running, probably made a mistake by calling this
+                // method in such a way that it resulted in such an obnoxious array. Therefore, to
+                // protect ourselves, we bail at this point.
+                throwOutOfMemoryError(exec);
+                return JSValue::encode(jsUndefined());
+            }
 
             // 5. Let p = e.
             // 8. Let q = p.
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