Péter Gál 5e483633f3
Fix prototype chain traversing (#4458)
After the introduction of the Proxy builtin object there was
a possibility to traverse the prototype chain with an invalid object.
The prototype was freed before it's data/properties were queried resulting
in accessing invalid information.

By forcing the allocator to always do a gc (`--mem-stres-test=on` build option)
it was possible to trigger the issue without complicated tests.

New internal method:
* `ecma_op_object_get_prototype_of` which always returns the prototype
  of an object and the return value must be freed (if it is valid).

Updated prototype chain traversing in:
* `jerry_object_get_property_names`
* `ecma_builtin_object_prototype_lookup_getter_setter`
* `ecma_op_function_has_instance`
* `ecma_op_function_get_super_constructor`
* `ecma_op_object_is_prototype_of`
* `ecma_op_object_enumerate`

Removed method `ecma_proxy_object_prototype_to_cp`

JerryScript-DCO-1.0-Signed-off-by: Peter Gal pgal.usz@partner.samsung.com
2021-01-15 20:54:09 +01:00
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