[builtins] Fix handling of read-only length in Array.prototype.pop

Bug: v8:10484
Change-Id: I977c5974d33472f5af20d7646ad4cf2c58049632
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2182452
Commit-Queue: Igor Sheludko <ishell@chromium.org>
Reviewed-by: Toon Verwaest <verwaest@chromium.org>
Cr-Commit-Position: refs/heads/master@{#67612}

src/builtins/builtins-array.cc

@@ -2,6 +2,7 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
+#include "src/base/logging.h"
 #include "src/builtins/builtins-utils-inl.h"
 #include "src/builtins/builtins.h"
 #include "src/codegen/code-factory.h"
@@ -471,6 +472,15 @@ BUILTIN(ArrayPop) {
     uint32_t new_length = len - 1;
     ASSIGN_RETURN_FAILURE_ON_EXCEPTION(
         isolate, result, JSReceiver::GetElement(isolate, array, new_length));
+
+    // The length could have become read-only during the last GetElement() call,
+    // so check again.
+    if (JSArray::HasReadOnlyLength(array)) {
+      THROW_NEW_ERROR_RETURN_FAILURE(
+          isolate, NewTypeError(MessageTemplate::kStrictReadOnlyProperty,
+                                isolate->factory()->length_string(),
+                                Object::TypeOf(isolate, array), array));
+    }
     JSArray::SetLength(array, new_length);
   }
 

test/mjsunit/regress/regress-v8-10484-1.js

+// Copyright 2020 the V8 project authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+var ar;
+Object.defineProperty(Array.prototype, 3,
+    { get() { Object.freeze(ar); } });
+
+function foo() {
+  ar = [1, 2, 3];
+  ar.length = 4;
+  ar.pop();
+}
+
+assertThrows(foo, TypeError);
+assertThrows(foo, TypeError);
+assertThrows(foo, TypeError);
+assertThrows(foo, TypeError);

test/mjsunit/regress/regress-v8-10484-2.js

+// Copyright 2020 the V8 project authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+var ar;
+Object.defineProperty(Array.prototype, 3,
+    {
+      get() {
+        Object.defineProperty(
+            ar, "length",
+            { value: 3, writable: false, configurable: false });
+      }
+    });
+
+function foo() {
+  ar = [1, 2, 3];
+  ar.length = 4;
+  ar.pop();
+}
+
+assertThrows(foo, TypeError);
+assertThrows(foo, TypeError);
+assertThrows(foo, TypeError);
+assertThrows(foo, TypeError);