YJIT: Fix gen_expandarray treating argument as VALUE #6603
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The expandarray instruction interpreters its arguments as rb_num_t. YJIT was treating the num argument as a VALUE previously and when it has a certain bit pattern, it can look like a GC pointer. The argument is not a pointer, so YJIT crashed when trying to mark those pointers. This bug existed previously, but our test suite didn't expose it until f55212b. TestArgf#test_to_io has a line like: a1, a2, a3, a4, a5, a6, a7, a8 = array Which maps to an expandarray with an argument of 8. Qnil happened to be defined as 8, which masked the issue. Fix it by not using the argument as a VALUE.
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The expandarray instruction interpreters its arguments as rb_num_t. YJIT was treating the num argument as a VALUE previously and when it has a certain bit pattern, it can look like a GC pointer. The argument is not a pointer, so YJIT crashed when trying to mark those pointers.
This bug existed previously, but our test suite didn't expose it until f55212b. TestArgf#test_to_io has a line like:
Which maps to an expandarray with an argument of 8. Qnil happened to be defined as 8, which masked the issue.
Fix it by not using the argument as a VALUE.