Hi Ian,

    I noticed that you move the Bits class template  from arm.cc to
reloc.h recently.  I found that the minimum number of bits is 0 in
various methods, this is mostly likely my bug.  If bits == 0,
expressions like "1U << (bits - 1)" are undefined.  If changed lower
bound from 0 to 1 in all assertions in the Bits class template.  In
addition, I also change some related code in arm.cc.  This is tested
on both x86_64 and ARM.

-Doug


2012-02-02  Doug Kwan  <dougkwan@google.com>

        * arm.cc (Arm_relocate_functions::abs8,
        Arm_relocate_functions::abs16): Use
        Bits::has_signed_unsigned_overflow32.
        (Arm_relocate_functions::thm_abs8): Correct range of
        overflow check.
        * reloc.h (Bits class): Change minimum number of bits from 0 to 1
        in assertions.