Assert in Object.getPrototypeOf function

[kkristof]

Hi, I'm currently working on the Object.create built-in function and I've found that the following code cause below causes assertion.
The test:

var obj = Object.create(null);
Object.getPrototypeOf (obj);

The assertion:

ICE: Assertion 'object_p != NULL' failed at /home/kristof/work/jerryscript/jerry-core/ecma/base/ecma-helpers-value.cpp(ecma_make_object_value):267.
Error: ERR_FAILED_INTERNAL_ASSERTION

Backtrace:

#0  0x00000000004d9ae5 in syscall_2_asm () at /home/kristof/work/jerryscript/jerry-libc/target/linux/jerry-asm.S:32
#1  0x000000000040099a in syscall_2 (syscall_no=62, arg1=6944, arg2=6) at /home/kristof/work/jerryscript/jerry-libc/target/linux/jerry-libc-target.c:96
#2  0x0000000000400b3b in abort () at /home/kristof/work/jerryscript/jerry-libc/target/linux/jerry-libc-target.c:175
#3  0x000000000045c10b in jerry_fatal (code=ERR_FAILED_INTERNAL_ASSERTION) at /home/kristof/work/jerryscript/jerry-core/jrt/jrt-fatals.cpp:70
#4  0x000000000045c15a in jerry_assert_fail (assertion=0x4f2ce7 "object_p != NULL", file=0x4f2c78 "/home/kristof/work/jerryscript/jerry-core/ecma/base/ecma-helpers-value.cpp", 
    function=0x4dccf0 <_ZZ22ecma_make_object_valuePK13ecma_object_tE8__func__.25845> "ecma_make_object_value", line=267) at /home/kristof/work/jerryscript/jerry-core/jrt/jrt-fatals.cpp:97
#5  0x000000000048a97f in ecma_make_object_value (object_p=0x0) at /home/kristof/work/jerryscript/jerry-core/ecma/base/ecma-helpers-value.cpp:267
#6  0x00000000004223ec in ecma_builtin_object_object_get_prototype_of (this_arg=1807, arg=2855) at /home/kristof/work/jerryscript/jerry-core/ecma/builtin-objects/ecma-builtin-object.cpp:133
...

[kkristof]

Note that, on the current master this isn't reproducible because the only way to create any object with the prototype of null is using the Object.create.

cc @bzsolt @galpeter

[galpeter]

The problem seems to be that the ecma_get_object_prototype return a null pointer and we call the ecma_make_object_value on it. Probably we should check and if such case occurs return a simple null value instead.