Summary: unaligned stack in throw_NullPointerException_at_call_entry().
Reviewed-by: twisti, never, kvn

Summary: Adjust the assert and code in eliminate_card_mark() method for case when stored value is NULL.
Reviewed-by: iveresov, never

Summary: LLVM-GCC (__llvm__) should use the same _get_previous_fp implementation as __clang__ (as is the case for os::current_stack_pointer).
Reviewed-by: twisti, never, dcubed

Reviewed-by: jcoomes